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Infected femorodistal bypass: Is graft removal mandatory?
Infected femorodistal bypass: Is graft removal mandatory? K e n n e t h J. Cherry, Jr., M D , Christopher F. Roland, M D , Peter C. Pairolero, M D , J o h n W. Hallett, Jr., M D , N. Bradly Meland, M D , James M. Naessens, M P H , Peter Gloviczld, M D , and Thomas C. Bower, M D , Rochester, Minn. Infected lower extremity bypass grafts have been associated with high rates of limb loss. Traditionally treatment has included graft excision. To compare aggressive local treatment, without graft removal, with more conventional graft excision, we reviewed 38 consecutive patients with 39 infected lower extremity bypasses treated during the last 10 years. The grafts used were prosthetic in 33 cases, vein in 4, and composite in 2. Median fiallow-up was 2.7 years. Twenty-eight infected grafts were treated with either complete (14) or partial (14) graft removal. Nine new grafts were placed. Recurrent infection developed in five cases, and two patients died of complications of graft infection. Ten of 20 limbs at risk were lost. Eleven patients with patent bypasses (4 vein, 2 composite, 5 prosthetic) were treated without graft excision. Treatment of five patients in this group included muscle transposition. Five patients were treated with incision and drainage of abscesses, and one had excision of a persistent sinus tract. One patient underwent major amputation 6.3 years after treatment of graft infection. Limb salvage was significantly higher (p = 0.012, log-rank test) than in patients treated with graft excision. One patient died, and no recurrent infections developed; these were not significant differences oampared with those having graft excision. We conclude that aggressive local treatment of infected lower extremity bypass grafts, including drainage, debridement, and muscle ta:ansposition may treat infection in selected patients without the need for graft removal a~ad with rates of limb salvage superior to those obtained with excisional therapy. (J VAsc SURG 1992;15:295-305.)
Infection involving arterial bypass grafts in the lower extremities is a major and feared complication of vascular reconstruction. Whereas the incidence of graft infection after femorodistal bypass is only 2% to 3%, ~-3the resulting mortality rat e ranges from 4% to 27%, with amputation rates as high as 62.5%. 2,4-6 Excision of the infected arterial graft, with or without reconstruction, has been considered conventional therapy. It has long been recognized, however, that not all infected bypasses need to be removed. 1,7 Recent reports have described the treatment of infected lower extremity arterial grafts with aggressive local tissue debridement, administration of local and systemic antibiotics, and coverage by muscle From the Section of Vascular Surgery, Section of Plastic and ReconstructiveSurgery,and the Sectionof Biostatistics,Mayo Clinic and Mayo Foundation, Rochester. Presented at the Forty-fifthAnnual Meeting of the Societyfor Vascular Surgery, Boston,Mass., june 4-5, 1991. Reprint requests: Kenneth J. Cherry, ~r., MD, Mayo Clinic, Rochester, MN 55905.
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transposition, s-ll Many of these infected bypass grafts have been successfully treated without excision. The present study was undertaken to review our experience with infected femorodistal bypasses and to compare aggressive local treatment, without graft removal, with more conventional graft excision. PATIENTS AND METHODS Between July 1, i979, and July 1, 2990, we treated 38 patients with 39 infected lower extremity bypass grafts. Twenty-five were men, and 13 were women. Their ages ranged from 33 to 89 years (mean, 65 years). One man was treated for infected grafts of both lower extremities. Twenty-three of the infected grafts were originally implanted at this institution; 16 were placed at other hospitals before referral. Information was obtained by retrospective chart review and direct contact with patients or their physicians. Follow-up was complete to death or time of data collection in 30 patients (79 %). Eight patients were lost to follow-up from 1 month to 6 years after 295
296 Cherry et al.
definitive treatment of their graft infection. Median follow-up for those last known alive is 2.7 years. Graft infection was defined by clinical criteria, including exposed purulent graft, sinus tract or abscess involving the graft, infected pseudoaneurysm, or cellulitis at the graft site. All graft infections fell into group III, IV, or V in the classification system from the Montefiore Medical Center. 12 Wound or skin infections not involving the graft were excluded. Late graft patency was determined by pulse examination, anlde-brachial pressure index, arteriography, or operative findings. Patient survival and limb salvage were analyzed with Kaplan-Meier curves, although smaller sample sizes tended to result in greater standard errors. The potential association of clinical variables with a "poor result" (i.e., amputation, reinfection after treatment, or death related to graft infection) was assessed by use of the log-rank test for nominal variables and Cox regression model for ordinal and continuous variables. Patients with previous major amputation were excluded from this analysis. An insufficient number of events existed to develop a valid multivariant model. Chi-square analysis or Fisher's Exact Test (when the number of events was small) were used to compare clinical factors in patients treated with and without graft excision. Only the first graft of the patient with two graft infections was used in analyzing possible associations. Ap value less than 0.05 was considered statistically significant. All tests were two tailed. RESULTS The indication for femorodistal bypass grafting was claudication in 15 cases (38.5%) and limbthreatening ischemia in 19 (48.7%). Four patients (10.3%) had aneurysmal disease, and one (2.6%) underwent bypass at the time of excision of a soft tissue sarcoma. Twenty-seven of the infected grafts (69.2%) were expanded polytetrafluoroethylene (PTFE), six grafts (15.4%) were Dacron, four grafts (10.3%) were autologous saphen0us vein, and two grafts (5.1%) were composites of PTFE and vein. The type of graft material used at the time of the original procedure and the level of the proximal and distal anastomoses are detailed in Table I. Twelve patients had undergone previous aortofemoral bypass, and three patients underwent concomitant aortofemoral and femorodistal bypass. Three patients had proximal femorofemoral bypass, and one each had proximal iliofemoral or axiUofemoral bypass. Thirty-two of the 39 original bypass operations were performed in the presence of presumed systemic
lournal of VASCULAR SURGERY
or local risk factors for infection, most commonly previous groin operation or diabetes (Table II). Seven patients had documented infection at distant sites in the perioperative period (three urinary tract infections, one respiratory infection, and three soft tissue infections). Superficial wound infections developed in 11 patients after the initial procedure (6 proximal, 4 distal, and 1 both proximal and distal). The median time from placement of the femorodistal bypass to the initial symptom of graft infection was 48 days (range, 2 days to 8.8 years). Median time from graft placement to definitive treatment of the graft infection was 130 days (range, 20 days to 8.9 years). Nineteen grafts (49%) were occluded at the time they presented with infection. A localized collection of purulent material adjacent to the graft was the most common manifestation of infection, being present 51% of the time. Infected sinus tracts, ceUulitis involving the graft, and systemic sepsis were also relatively common (Table III). In 14 patients the diagnosis of graft infection was made on clinical grounds in the presence of cellulitis, infected sinus tracts, abscesses, or other signs of local infection. The remaining 25 patients underwent a total of 38 diagnostic procedures, most commonly CT scanning, ultrasonography, or white blood cell scans labeled with indium 111 (Table IV). In addition, 15 patients underwent angiography before definitive treatment of their graft infection. Graft infection was localized to the area of the proximal anastomosis in 17 cases (43.6%) and to the area of the distal anastomosis in 11 (28.2%). Seven patients (17.9%) had infection involving the entire graft. Two patients (5.1%) had isolated areas of infection involving a portion of the graft distant from both anastomotic sites, and two were infected at both anastomoses with an intervening uninvolved segment. Microbiologic cultures, obtained at the time of operation or by preoperative aspiration of localized collections, were positive in 35 of 39 cases (Table V). Eight patients had mixed bacteriology. Staphylococcus aureus was the most common pathogen (12 cases, 30.8%). Definitive treatment of the graft infections was divided into three groups: (1) excision of all or part of the infected graft without vascular reconstruction; (2) excision of the infected graft with vascular reconstruction; and (3) local treatment of the infected femorodistal bypass without graft excision, including drainage of localized collections, debridement of devitalized tissue, and, in some cases, rotation of muscle flaps for coverage.
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Infected femorodistal bypass and gra~ removal 297
Table I. Graft material and anastomotic sites Level of proximal anastomosis
Level of distal anastomosis
Material
No. ofgrafts
Prox bypassgraft
CFA
SFA
AIG"
BIG"
PTFE Dacron Composite Reversed vein Nonreversed vein In situ vein Total
27 6 2 2 1 _!1 39
15 4 0 0 0 _!1 20
11 1 2 1 0 0 15
1 1 0 1 1 0 4
9 4 0 1 0 _00 14
13 2 1 1 1 _!l 19
Tibial/peroneal 5 0 1 0 0 0 6
CFA, Comrnon femoral artery; SFA, superficial femoral artery; AKP, above-knee popliteal artery; BKP, below-knee popliteal artery.
G r o u p 1: Graft excision w i t h o u t vascular reconstruction (N = 19) Nineteen infected femorodistal bypass grafts were treated by partial (7) or total (12) graft excision without vascular reconstruction. Most anastomoses were at the common femoral level, whether to native artery or to graft in the groin area (Table I). After graft excision, those anastomoses were closed primarily or patched with vein or autogenous artery. When the proximal anastomosis was to the superficial femoral artery, that artery was ligated. Patent distal anastomotic sites were either patched or closed primarily. One patient also underwent transposition of the rectus femoris to cover the area of the graft excision. All of the grafts were prosthetic (4 Dacron, 15 PTFE), and 17 were occluded when they presented with infection. Infection of occluded grafts developed in seven patients in limbs previously amputated; these infections were significant rather than incidental and prompted hospitalization. Three of these patients presented with nonsalvageablc extremities, and four were judged to have nonreconstructible vessels. One patient underwent excision of a patent infected graft and above-knee amputation at the same: operation. Six of the remaining 11 limbs at risk within this treatment group required major amputations after excision of the infected graft. One of these amputations occurred in the other patient with a patent graft who suffered recurrent infection and subsequent death related to graft infection. G r o u p 2: Graft excision and arterial reconstruction (N = 9) Nine infected prosthetic femorodistal bypass grafts were treated by partial (7) or total (2) graft excision and femorodistal arterial reconstruction (Table VI). Seven of the grafts were patent; the two occluded grafts were associated with distal ischemia. In contrast to patients in group 1, all of these patients were thought to have salvageable extremities and
Table II. Local and systemic risk factors for graft infection
Previous groin operation Diabetes Obesity Concomitant minor amputation Malignancy Emergency operation Steroid use Groin irradiation
No. of,~rafts
(%)
25 15 5 5 3 3 2 1
(64.1) (38.5) (12.8) (12.8) (7.7) (7.7) (5.1) (2.6)
Table III. Presenting signs of infection
No. ofgrafts Abscess adjacent to graft 20 Infected sinus tract 15 Cellulitis 11 Systemic sepsis 8 Hemorrhage 4 Pseudoaneurysm 4 Graft exposure 4 Poor tissue incorporation 2 Acute arterial ischemia and graft thrombosis 1 Septic emboli 1
(%) (51.3) (38.5) (28.2) (20.5) (10.3) (10.3) (10.3) (5.1) (2.6) (2.6)
reconstructible vessels. Reconstruction was performed by extraanatomic routes (6) or with autogenous material (3). In one patient the rectus femoris was transposed to cover the new proximal anastomosis; this patient was the only infection related death within this group. The revision in this patient was an autogenous reconstruction. The patient, whose cultures grew Candida tropicalis, Klebdella oxytoca, and Staphylococcus epidermidis, developed recurrent infection of the native arteries with massive hemorrhage leading to amputation and death. There were three other recurrent graft infections, two of which were treated successfully. S. aureus infection developed in one man in both of his groin wounds after extraanatomic bypass grafting. These wounds
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TaMe IV. Tests initiated in diagnosis of graft infection (25 patients) Test
Positive Result
Negative Result
Equivocal Result
Total
9 5 4 2 0 0 1
2 2 1 1 1 1 0
6 1 2 0 0 0 0
i7 8 7 3 1 1 I
CT scan Indium WBC scan Ultrasonography Percutaneous aspiration MRI Gallium scan Sinogram
WBC, White blood cell; MRI, magnetic resonance imaging.
Table V. Bacteriology of femorodistal graft infection
Staphylococcus aureus Gram-negative bacilli (not pseudomonas organisms) Group D streptococci Coagulase-negative staphylococci Pseudomonas organisms Fungal pathogens Anaerobic pathogens Non-group D streptococci Others No growth
No. of cases
(%)
12 11
(30.8) (28.2)
5 4 3 3 3 2 3 4
(12.8) (10.3) (7.7) (7.7) (7.7) (5.1) (7.7) (10.3)
Eight patients (20.5%) had mukiple organisms.
were treated successfully with debridement and appropriate antibiotic coverage. S. epidermidis reinfection of the remaining PTFE graft in the groin developed in another patient. This was successfully removed. The third patient developed a recurrent S. aureus infection of an obturator bypass, which required amputation. In only four patients was treatment with excision and arterial reconstruction entirely successful, that is, with no incidence of reinfection, amputation, or loss of life. Group 3: Nonexcision of grafts (N = 11) Eleven patients with infected fcmorodistal bypasses were treated without excision of the infected graft (Table VII). Within this group were five prosthetic, four vein, and two composite (proximal PTFE, distal vein) grafts. All grafts were patent. Six of these patients had abscesses adjacent to the graft; primary treatment consisted of incision and drainage and local debridement of devitalized tissues. In addition, two patients were treated with open packing of the wound, and two had the proximal sartorius muscle transposed to cover the area of the graft infection. Two patients with infected sinus tracts were treated primarily with debridement; one
subsequently underwent a rectus femoris transposition. Two patients with signs of systemic sepsis and localized cellulitis were treated with debridement and either rectus femoris transposition (1) or open packing (i). The remaining patient in this group had an infected pseudoaneurysm and sinus tract; treatment consisted of pseudoaneurysm repair with an interposition Dacron graft between his Dacron aortofemoral bypass graft and his Dacron femoropopliteal bypass graft, wound and sinus tract debridement, and rectus femoris transposition. His cultures revealed no growth. One of the patients treated without graft excision died 3 months after operation of pulmonary complications. The graft was patent at the time of death. One sartorius muscle flap became necrotic but was debrided and successfully replaced with a rectus femoris flap. Two grafts developed late occlusions ( > 5 years after treatment of graft infection). One of these resulted in above-knee amputation. Neither had evidence of infection. The other eight grafts have been patent to latest follow-up, without signs of recurrent infection. Overall, treatment of the 39 infected femorodistal bypasses resulted in 3 related deaths, 11 amputations (32 limbs at risk), and 5 reinfections, as delineated by the summary of results by treatment group in Table VIII. The likelihood of developing any of these "poor outcomes" was increased in the presence of infection with coagulase-negative staphylococcus (p = 0.033) or fungal pathogens (p = 0.007) and in those patients in whom reconstruction with vein grafts after excision of the infected graft was part of their treatment (p = 0.024). Poor outcome was not associated with the primary use of a vein as the arterial conduit. Poor outcomes were less likely in patients whose original grafts were placed at this institution (p = 0.0362) and in those treated without graft excision (p = 0.007). In contrast, a number of variables were not associated with an adverse outcome (p > 0.05). These variables included gender,
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Infected femorodistal bypass and graft removal 2 9 9
TaMe VI. Patients treated with graft excision and femorodistal reconstruction Type of graft
Type and location of infection
Portion of graft resected
PTFE
Abscess, distal anastomosis
Distal graft
PTFE
Abscess, hemorrhage, proximal anastomosis Sinus tract, cellulitis, proximal anastomosis Systemic sepsis, sinus tract, distal anastomosis
Proximal graft
Dacron PTFE PTFE
Infected pseudoaneurysm, proximal anastomosis Abscess, proximal anastomosis
PTFE PTFE PTFE PTFE
Proximal graft Distal graft Proximal graft Proximal graft
Infected pseudoaneurysm, proximal anastomosis Hemorrhage, exposed graft, proximal anastomosis
Proximal graft
Abscess, sinus tract, distal anastomosis
Entire graft
Entire graft
Method of reconstruction
Result
Femorodorsal pedal bypass (saphenous vein) Obturator bypass (Dacron) to retained distal graft Obturator bypass (Dacron) to retained distal graft Anterior tibial bypass (PTFE), via lateral tunnel, from proximal retained graft Axillopopliteal bypass (PTFE)
Recurrent infection in retained PTFE graft at 13 mo Doing well at 48 mo
Obturator bypass (PTFE) to retained distal graft Obturator bypass (PTFE) to retained distal graft Femoropopliteal bypass (saphenous vein), rectus femoris transposition Femorofemoral bypass (endartereetomized SFA) and femoropopliteal bypass (saphenous vein)
Doing well at 26 mo
Reinfection, graft occlusion, MZA at 19 mo Occlusion, AKA at 2 days Doing well at 42 mo
Doing well at 3 mo Reinfection, AICA, death at 25 days Reinfection at 30 days, treated with debridement, now doing well at 4 mo
Table VII. Patients treated without graft excision Type ofgraft
Type and location of infection
Treatment
PTFE
Systemic sepsis and cellulitis, proximal anastomosis
Multiple debridements, rectus femoris transposition
Vein
Infected sinus tract, proximal graft (not anastomotic) Abscess, distal anastomosis Abscess, proximal anastomosis
Debridement, rectus femoris transposition Incision and drainage Incision, drainage, debridement, sartorius muscle transposition Incision and drainage, packing Incision and drainage
PTFE Composite (prox PTFE distal vein) PTFE Vein
Abscess, distal anastomosis Abscess, distal anastomosis
Vein PTFE
Infected sinus tract, mid graft Systemic sepsis, cellulitis, distal anastomosis Abscess, distal anastomosis
Debridement Incision and drainage, packing
Composite (prox PTFE, distal vein)
Abscess, proximal anastomosis
Dacron
Infected pseudoaneurysm, sinus tract
Debridement, antibiotic irrigation, sartorius muscle transposition Repair, debridement, rectus femoris transposition
Vein
diabetes, previous groin operations, indication for the original operation, perioperative wound or distant infections, concomitant aortofemoral grafting, graft material, location of anastomoses, graft patency, presentation of infection (abscess versus cellulitis versus sinus tract), location of infection, and infection with S. a u r e u s or gram-negative bacilli. The results for the three different treatment groups, delineated by graft material, are presented in Table IX, and
Incision and drainage
Result Death from postoperative respiratory insufficiency at 3 mo (graft patent) Death from unrelated cause at 11 mo Doing well at 32 mo Necrosis of sartorius, salvage with rectus femoris transposition, doing well at 25 mo Doing well at 48 mo Death from unrelated cause at 21 mo Doing well at 32 mo Doing well at 5 mo Death from unrelated cause at 62 mo Occluded at 62 mo Occlusion, AICA at 76 mo
Kaplan-Meier probability curves of limb salvage and survival free of amputation and reinfection are presented in Figs. 1 and 2. Patients treated without graft excision had a significantly higher limb salvage rate (p = 0.012, log-rank test) than did those treated with partial or total graft excision. Differences in mortality and reinfection rates, when considered alone, were not significant. Patients treated without graft excision
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Table V I I I . Summary o f results by treatment group Treatment ofgraft infection
Group 1 Graft excisionwithout reconstruction Group 2 Graft excisionand femorodistalreconstruction Group 3 Local treatment without graft excision Total
Deaths related to graft infection
No. ofgrafts
Reinfection
Amputation
19
1
7
1
9
4
3
1
11 39
0 5
1 11
_1 3
Table IX. Results o f femorodistal graft infection, related to graft material and treatment No. ofgrafls and results of treatment Group 1 (graft excision)
Group 2 (graft excision and revascularization)
Vein
0
0
Composite (PTFE + vein)
0
0
Graft material
Dacron
PTFE
4 No reinfection,limb loss, or death from graft infection
i5 7 amputations 1 death
1 1 reinfection I amputation
8 3 reinfections 2 amputations 1 death
were more likely to have had their grafts placed at this institution (p -- 0.002), to have patent grafts (p = 0.00I), and to have vein grafts (p = 0.012). Although the time from graft placement to treatment o f graft infection tended to be shorter in this group, (median, 55 days versus 216 days), it did not reach statistical significance (p = 0.156 rank sum test). Numerous other variables o f demographics, presentation, and microbiology were not significantly different between the patients treated with and without graft excision.
DISCUSSION It seems paradoxic that nonexcisional therapy o f infected femorodistal grafts would yield a better limb salvage rate and similar reinfection and mortality rates as traditional excisional treatment, with or without reconstruction. Certainly the small number o f patients in this study and the variations o f
Group 3 (no graft excision)
4 No reinfection,limb loss, or death from graft infection 2 No reinfection,limb loss, or death from graft infection; 1 occlusion at 62 months, viable limb 1 No reinfection,limb loss or death from graft infection; i late occlusion (at 76 months); amputation; no evidenceof infection 4 i death at 3 months without evidence of graft infection
treatment offered make definitive conclusions impossible. The study was retrospective, and was undertaken because of the clinical impression that t h o s e patients whose infected grafts were not excised but were treated locally (albeit by a variety o f methods) seemed to have a better rate o f limb salvage. That impression was borne out. However, the groups were dissimilar in significant ways. The three groups o f patients reported on were so congregated in an attempt to bring some order to the comparison. At first we compared simply two groups, those having traditional excisional therapy and those not. H o w ever, the high number o f amputations in those patients having graft excision without reconstruction would have unfairly impugned conventional excision and reconstruction if the two groups were studied together. Many o f these patients, who were classified as group 1, presented with previous amputations or with nonviable (3) or nonreconstructible (4) extrem-
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Infectedfemorodistal bypassand gra3~ removal 301 1.0 Group 3
0.8 0.6
2
0.4
Group 2
_--I
Group 1
0.2
0 0 Group 1 Graft excision without r(K;onstruction Group 2 Gra# excision with f~rnorodislai reconstruction Group, 3 NO graft excision
I
I
I
I
I
I
I
I
I
I
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
Years n = 10
4
4
3
3
n=
9
4
4
3
1
n = 11
10
8
7
4
2
4
3 CG- 13G~5~6-1B
Fig. 1. Kaplan Meier analysis of probability of limb salvage delineated by treatment group.
ities. The higher percentage of patients presenting with occlusion in this group (89.5%) as contrasted with the percentage of patients presenting with occlusion in group 2 (22.2%) and group 3 (0%) is striking evidence of the differences in the groups, the challenges posed, and in the expected outcomes. Further division of the groups into those with patent, stenotic, or occluded grafts would have been interesting. The small number of patients in these subsets and the different variables would have made these data uninterpretable. Our definition of reconstruction was restricted to that of redo of the primarily placed femoropopliteal or femorotibial graft. Profundaplasties were used in two patients in group 1 in fieu of redo femorodistal grafts with beneficial results. The patients in group 3 were treated for graft infection at a median interval of 55 days from graft placement, whereas the other two groups were treated at a median interval of 216 days. Although this difference was not statistically significant, we felt that it was of major clinical significance. Ehrenfeld (personal communication) has shown that early prosthetic groin infections can be well treated with meticulous local care and that there is steady advancement of granulation tissue over the infected prostheses. It may be that early infections are more easily handled by aggressive local measures than are late infections, which are well established in nonincorpo-
rated material. Timing of intervention may thus be a factor in determining the best treatment option. All patients with infected saphenous vein and composite grafts underwent nonexcisional treatment even when the prosthetic portion was involved in the infection. A sharp difference of opinion existed within our group concerning the merits of the two basic forms of therapy: resection or aggressive local treatment for infected prosthetic grafts. Nonexcisional therapy was probably offered more commonly to those patients with early infections. These patients were more often our own, perhaps making early detection and treatment more likely. Femorodistal grafts are probably more likely to be patent at the time of early intervention than at a later date, and that patency would contribute to an improved salvage rate, as seen in the patients in group 3. That the limb salvage rate is better in the group of patients treated without excision than in those treated traditionally is at first surprising, but on reflection a number of possible reasons emerge. (1) Patients admitted with occluded infected grafts are already relatively ischemic, tmlikely to undergo immediate revascularization in the face of infection, and therefore probably at higher risk for amputation. (2) The distal anastomotic site chosen at the initial grafting procedure is presumably the most advantageous. Repeat revascularization as treatment for graft infection must necessarily be done at sites removed
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Cherry et al.
1.0 Group 3
0.8
._z, "• = .O
0.6
2
0.4
Group 1 Group 2
n
0.2 0
0 Group 1 Graft excision without reconstruction Group 2 Graft excision with femorodistal reconstruction Group 3 No graft excision
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
Years n = 10
4
4
3
3
n=
9
3
2
2
1
n = 11
10
8
7
4
2
1
4
3 ~ - 1300,.~00-~H9
Fig. 2. Kaplan Meier analysis of probability of survival free of recurrent infection or limb loss delineated by treatment group. from infection. The sites chosen for anastomoses are not as likely in these situations to be as anatomically or hemodynamically advantageous. (3) The use initially of prosthetic material implies an absent vein or one of poor quality. Prosthetic anastomoses to more distal sites remote from infection are not likely to have high patency rates. It is encouraging that the mortality rate did not increase with nonresectional treatment, which suggests that such therapy may be safely offered as a first option. If hemorrhage is a presenting symptom, and the graft is judged to be infected and not simply exposed and desiccated, excision is mandatory. In cases of overwhelming sepsis, excision may also be necessary. Less dramatic presenting symptoms, however, may allow a trial of aggressive local treatment rather than graft excision. The group from Montefiore Medical Center had excellent results treating infected, patent, nonbleeding grafts with aggressive local debridement. 9,12 Kwaan et al.8 reported excellent results using povidone-iodine suction irrigation systems. Transposition of muscle flaps has been reported by Mixter et al. 1° to work in 96% of cases. Our experience with infected aortofemoral grafts suggests that only 60% of these grafts so treated may be expected to heal. 13 On the other hand, rotational muscle flaps used in seven patients in the present series had only two failures, one of which was
salvaged with another muscle flap. The introduction of well-vascularized muscle into infected wounds reduces healing time and bacterial counts. These flaps may be better suited to femorodistal grafts than to aortofemoral grafts simply because the infected areas may be entirely encompassed and treated in the former and not in the latter. The wounds were prepared for the muscle by aggressive local care, especially debridement. When the wound appeared healthy and able to accept and support a muscle flap, transposition was carried out. This series lends support to all of these plans of nonresectional management. We have insufficient evidence to state that nonexdsional therapy is the treatment of choice for infected femorodistal bypass grafts. The study is retrospective, and there was no protocol for therapy. Decisions for treatment were made on clinical grounds by the individual staff surgeons and reflect the different preferences of each. We do, however, have strongly suggestive evidence that in the absence of hemorrhage and overwhelming sepsis, aggressive local management with drainage of localized collections, debridement of devitalized tissue, and drainage, packing, and/or rotational muscle flap coverage may provide superior limb salvage with the same reinfection and mortality rates as more conventional excisional therapy, with or without reconstruction.
Volume 15 Number 2 February 1992
Such nonresectional therapy represents a reasonable first step in the m a n a g e m e n t o f infected femorodistal grafts and provides a realistic expectation o f resolution o f the graft infection and salvage o f the limb w i t h o u t ~.e need for graft removal. REFERENCES i. SzilagyiDE, Smith RF, EUiott JP, Vrandecic MP. Infection in arterial reconstruction with synthetic grafts. Ann Surg 1972; 176:321..33. 2. Edwards WH Jr, Martin RS III, Jenkins JM, Edwards WH St, Mulherin JL Jr. Primary graft infections. J VAsc SURG 1987;6:235-9. 3. Johnson JA, Cogbill TH, Strutt PJ, Gundersen AL. Wound complications after infrainguinat bypass. Classification, predisposing factors, and management. Arch Surg 1988;123: 859-62. 4. Ehrenfeld WK, Wilbur BG, Olcott CN IV, Stoney RJ. Autogenous tissue reconstruction in the management of infected prosthetic grafts. Surgery 1979;85:82-92. 5. SeegerIM, Wheeler JR, Gregory RT, Snyder SO, Gayle RG. Autogenous graft replacement of infected prosthetic grafts in the femoral position. Surgery 1983;93:39-45. 6. LiekwegWG Jr, GreenfieldLL Vascular prosthetic infections: collected experience and results of treatment. Surgery 1977; 81:335-42.
Infected femorodistal bypass and graft removal 303
7. Carter SC, Cohen A, Whelan TJ. Clinical experience with management of the infected Dacron graft. Ann Surg I963; 158:249-55. 8. Kwaan JHM, Connolly JE. Successfulmanagement of prosthetic graft infection with continuous povidone-iodine irrigation. Arch Surg 1981;116:716-20. 9. Calligaro ICD, Veith FJ, Gupta SK, et al. A modified method for management of prosthetic graft infections involving an anastomosis to the common femoral artery. I VASC SURG 1990;11:485-92. 10. Mixter RC, Turnipseed WD, Smith DI Jr, Archer CW, Rao VK, Dibbell DG. Rotational muscle flaps: a new technique for covering infected vascular grafts. J VAsc SURG1989;9:472-8. 11. Meland NB, Arnold PG, Pairolero PC. Infected vascular prostheses: management with muscle transposition. (Submitted for publication). 12. Samson Rid, Veith FJ, Janko GS, Gupta SK, Scher LA. A modified classification and approach to the management of infections involving peripheral arterial prosthetic grafts. J VASCSFRG 1988;8:147-53. 13. Cherry 1<1Jr, Crepps IT Jr, Pairolero PC, et al. Abdominal aortic graft infections: management and tong-term outcome. Presented at the Thirteenth Annual Meeting of the Midwestern Vascular Surgical Society; September 29, 1989; Chicago, Ill. Submitted lmle 10, 1991; accepted Sept. 16, 1991.
DISCUSSION Dr. Jer~ T Goldstone (San Francisco, Calif.). According to the Random House Dictionary of the English language, "dogma" is defined as a specific tenet or doctrine authoritatively laid down, as by a church; or, a prescribed doctrine; or a settled or established opinion, belief, or principle. In this presentation, the authors have challenged the dogma that all infected prosthetic arterial grafts must be removed. Thirty-eight patients with 39 infected infrainguinal bypass grafts were the cohort for this presentation. The patients were divided into three groups based on whether or not the infected graft was excised and whether or not concominant femorodistal reconstruction was used. Overall, there was a 12.8% reinfection rate, a 32.2% rate of amputation of limbs at risk, and a 7.7% mortality rate. These results compare very favorably with those published by other experts dealing with similar patients. The surprising information presented today by Dr. Cherry was that although the reinfection and mortality rates between groups I, II, and III were the same, the limb salvage rate in the patients in whom the infected grafts were not excised was far better (90.9%) than in either of the other two groups where amputation rates were 54.5% and 33.3%. This has led the authors to conclude that nonresectional therapy represents a reasonable first step in the management of infected femoral distal grafts and provides a
realistic expectation for resolution of the graft infection and salvage of the limb without the need for graft removal. The most important question to be asked is whether the data support the conclusions. Certainly, as the authors point out, there is neither a sufficient number of patients nor sufficient evidence to state conclusively that nonexcisional therapy is the treatment of choice for infected femorodistal bypass grafts. I have several other comments, concerns, and questions to which I would like the authors to respond. The treatment groups were not similar. In group I, 17 of the 19 grafts were occluded. Seven of these were in limbs with previous amputation but 11 other limbs were at least potentially reconstructible, and yet, no reconstructions were attempted. Why not? In group II, 7 of the 9 grafts were patent, and in group III, all of the grafts were patent. As Dr. Cherry has pointed out, no standard treatment protocol existed for these infections. Treatment decisions were made on clinical grounds by individual surgeons based on their own preferences. It was of particular interest to me that 6 of the 11 grafts in the nonexcisional treatment group were surrounded by an abscess, and these apparently did well with incision, drainage, and local treatment. In the statistical analysis, bad outcomes were significantly related to infections with S. epidermidis and the
304
Cherry et al.
presence of saphenous vein as the infected graft. I would have predicted that these two factors would be associated with a more favorable outcome since S. epidermidis is relatively less virulent than many of the other organisms cultured from the graft infections in this series, and since autogenous tissue, that is vein, is known to have better healing potential in the presence of infection than do prosthetics. Do the authors have an explanation for this? The median time from graft implantation to treatment of the subsequent infection was 55 days for the nonexcised grafts and 216 days for the grafts that were excised. Although this difference of 161 days was not statistically significant, it seems to me to be clinically significant, suggesting that if nonexcisional therapy is appropriate, it may be so for early rather than late graft infections. Similarly, patients who received their initial grafting operation at the Mayo Clinic were more likely to have their graft infections treated by nonexcisional therapy. Does this represent treatment bias favoring their own patients, or is there some other explanation for this trend? The authors claim that one of the reasons for the high amputation rate in the reconstructed patients is that the original grafts were performed at the most advantageous distal anastomotic site, and therefore to treat the ischemia less advantageous anastomotic sites needed to be selected. Based on my own experience, I disagree. Many of the patients that we see at our tertiary referral center have had their distal anastomoses made at the most convenient rather than the most advantageous location. These comments and concerns notwithstanding, I concur with the authors' conclusions that nonresectional therapy, as described in their presentation, represents a reasonable first step in the management of infected femoral distal grafts. It certainly will work in some patients. In stating this however, it must be emphasized that the authors followed sound surgical principles in the treatment of these patients, namely drainage of localized collections, debridement of devitalized tissues, and increase in local blood supply by the use of rotational muscle flaps. Readers of this article should be warned, however, that although rotational muscle flaps are attractive and may be helpful, they are not a panacea. They failed in two of seven patients (28.6%) in the present series, and we have had several failures in our own experience. Finally, nonexcisional treatment of prosthetic graft infections should be applied very cautiously if at all to infections elsewhere, particularly those involving an aortic prosthesis. Dr. Kenneth Cherry. You are right, they were indeed different groups, and I tried to make that dear. The first group, the group treated without excision, had infected, occluded, prosthetic grafts. Many of these patients had nonviable or nonreconstructible extremities on presentation, but some of those limbs that were not reconstructed were thought to be viable. Obviously that proved not to be true for all. In some the infection was so widespread that to reconstruct it in that situation would probably have risked the patient's life more than it would have given him a chance of salvaging the limb.
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Yes, I think that the differences in presentation are indeed responsible for the surgeons' selection of treatment, just as in the examples we talked about. Certainly with a patent saphenous vein graft, I think everyone felt that they could make the effort to save that and have a realistic expectation that it would work. The controversy was over what to do with patent infected prosthetic grafts. As to the question about why infections with S. epidermidis had a poor outcome, we can only surmise that these are indolent slow infections and that the graft infections may have presented at a later more advanced stage. The vein associated with poor outcome is that vein used in treating the infection as an autogenous reconstruction, not vein used initially. There were three of these used and it simply did not work well. We think that is because these veins were of poor quality, which is why the prosthetics had been chosen in the first place. We agree with you that earlier infections are better treated by aggressive local therapy than are late infections. We think that is one of the reasons our own patients may have done better in that they perhaps were diagnosed earlier. We also agree that the muscle flaps are not a panacea and the area must undergo aggressive debridement and standard surgical treatment to ready the area to receive the musde flap. We, too, have found that it does not work as well for aortic grafts, and we think it is simply because the extent of the aortic graft cannot be well encompassed by a rotational muscle flap. Dr. Frank Veith (New York, N.Y.). We have had a 19-year experience with graft-saving treatment for infected lower extremity prosthetic grafts and have developed a new classification system to facilitate this nonexcisional treatment. On the basis of this experience, now twice published in the JOURNALOF VASCULAR SURGERY, we concur with the authors' conclusions. In our series of more than 45 infected prosthetic peripheral grafts, all or a portion of the graft could be salvaged successfully in 75% of cases if anastomotic breakdown had not occurred. Our follow-up with these successes now extends to 19 years. However, 25% of our efforts ended in failure, either anastomotic breakdown with bleeding or failure of the wound to heal. We have been unable to predict these failures at the outset, and I would like to ask the authors if they have criteria other than anastomotic breakdown for determining when graft-saving treatment, such as they and we have advocated, will not work. Dr. John Connolly (Irvine, Calif.). As Dr. Cherry mentioned, Dr. Kwaan and I over 10 years ago published a paper in which we showed that infected prosthetic grafts in the groin could be managed by early conservative treatment in some selected patients. These cases were groin infections in patent aortofemoral grafts where infection is even more potentially disastrous, as you know, than in the leg. However, the modallties that we used successfully in that small series of cases are similarly applied to the leg.
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Infected femorodistal bypassand graft removal 305
I have found over the years that a patent infected saphenous vein bypass in the lower extremity that gets infected, can be successfully treated by open drainage and proper antibiotics, because we are dealing with autogenous tissue. Prosthetic graft infection, however, is much more difficult to handle. If it is an infected femoropopliteal bypass or femorodistal bypass, and is occluded, we would remove the graft and reconstruct later. If it is a patent functioning graft where the viability of the foot is dependent on the bypass we would try drainage, debridement, appropriate antibiotics, continuous povodoneiodine administration. Secondary closure or muscle rotation would be performed only after the wound is sterile. If we cannot sterilize the wound, we would then remove the graft. When we reported our series over 10 years ago, the only things that were new in it were the use of continuous povodone iodine and muscle rotation. I would like to ask the authors if they have used povodone-iodine and if they thought it could improve their results. Obviously conservative management is not a panacea, but is something that I think is worth trying in desperate cases where the graft is infected and the leg is dependent on it and it will be necessary to revascularize if the graft is taken OUt.
The other thing that I would like to stress is to remember that if you do successfully treat such a patient, infection can occur even years later, and therefore we instruct the patient carefully to return to us at the first sign of fever, redness, or malaise that might lead us to believe that recurrent infection is occurring. Dr. William Turnipseed (Madison, Wis.). I strongly
support the idea that a fimctional and patent graft with structurally intact anastomoses in many cases can be saved. Our experience has been that if you cannot completely excise the pseudosheath around the graft that it becomes a locus for bacterial hiding, and that is one of the causes for failure. Are there circumstances where you might consider a modification of your technique and cut out segments of the graft to put in a clean piece and then cover it? We have concluded from our experience that if you can preserve the collateral system through the deep femoral artery or through the hypogastric vessels when you remove a functional graft, many of these limbs although ischemic will in fact survive. Do you have any commentary on that? Dr. Cherry. I will answer Dr. Veith's questions first. First of all, we appreciate his comments, and his work helped prompt this study. I do not think that we do know how to predict which ones will fail, Dr. Veith. Whether those predictors of poor outcome that we found in this small group of patients will hold up in a larger group or not I just do not know. To answer Dr. Connolly's questions, yes, some of the patients did have povodone-iodine irrigation and we do not hesitate to use that if it looks as if it would help. Just as you said, treatment of the patent infected prosthetic graft is more of a dilemma than the autogenous graft. We agree with Dr. Turnipseed that the pseudosheath does need to be excised, that you do have to have a clean bed for muscular flaps to work. Some partial excisions were done. We included those in the excisional group. We also agree that the hypogastric and deep circulations can salvage a leg that otherwise might be lost.
B O U N D VOLUMES AVAILABLE TO SUBSCRIBERS Bound volumes of the Jo~3vav~ OF VASCULARSURGERY for 1992 are available to subscribers only. They may be purchased from the publisher at a cost of $65.00 for domestic, $85.55 for Canadian, and $81.00 for international subscribers for Vol. 15 (January to June) and VoL 16 (July to December). Price includes shipping charges. Each bound volume contains a subject and author index, and all advertising is removed. Copies are shipped within 60 days after publication of the last issue in the volume. The binding is durable buckram with the journal name, volume number, and year stamped in gold on the spine. Payment must accompany all orders. Contact Subscription Services, Mosby-Year Book, Inc., 11830 Westline Industrial Drive, St. Louis, MO 63146-3318, USA. In the United States call toll free: (800)325-4177, ext. 4351. I n Missouri or foreign countries call: (314)453-4351. Subscriptions must be in force to qualify. Bound volumes are not available in place of a regular JOURNALsubscription.
Infection involving arterial bypass grafts in the lower extremities is a major and feared complication of vascular reconstruction. Whereas the incidence of graft infection after femorodistal bypass is only 2% to 3%, ~-3the resulting mortality rat e ranges from 4% to 27%, with amputation rates as high as 62.5%. 2,4-6 Excision of the infected arterial graft, with or without reconstruction, has been considered conventional therapy. It has long been recognized, however, that not all infected bypasses need to be removed. 1,7 Recent reports have described the treatment of infected lower extremity arterial grafts with aggressive local tissue debridement, administration of local and systemic antibiotics, and coverage by muscle From the Section of Vascular Surgery, Section of Plastic and ReconstructiveSurgery,and the Sectionof Biostatistics,Mayo Clinic and Mayo Foundation, Rochester. Presented at the Forty-fifthAnnual Meeting of the Societyfor Vascular Surgery, Boston,Mass., june 4-5, 1991. Reprint requests: Kenneth J. Cherry, ~r., MD, Mayo Clinic, Rochester, MN 55905.
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transposition, s-ll Many of these infected bypass grafts have been successfully treated without excision. The present study was undertaken to review our experience with infected femorodistal bypasses and to compare aggressive local treatment, without graft removal, with more conventional graft excision. PATIENTS AND METHODS Between July 1, i979, and July 1, 2990, we treated 38 patients with 39 infected lower extremity bypass grafts. Twenty-five were men, and 13 were women. Their ages ranged from 33 to 89 years (mean, 65 years). One man was treated for infected grafts of both lower extremities. Twenty-three of the infected grafts were originally implanted at this institution; 16 were placed at other hospitals before referral. Information was obtained by retrospective chart review and direct contact with patients or their physicians. Follow-up was complete to death or time of data collection in 30 patients (79 %). Eight patients were lost to follow-up from 1 month to 6 years after 295
296 Cherry et al.
definitive treatment of their graft infection. Median follow-up for those last known alive is 2.7 years. Graft infection was defined by clinical criteria, including exposed purulent graft, sinus tract or abscess involving the graft, infected pseudoaneurysm, or cellulitis at the graft site. All graft infections fell into group III, IV, or V in the classification system from the Montefiore Medical Center. 12 Wound or skin infections not involving the graft were excluded. Late graft patency was determined by pulse examination, anlde-brachial pressure index, arteriography, or operative findings. Patient survival and limb salvage were analyzed with Kaplan-Meier curves, although smaller sample sizes tended to result in greater standard errors. The potential association of clinical variables with a "poor result" (i.e., amputation, reinfection after treatment, or death related to graft infection) was assessed by use of the log-rank test for nominal variables and Cox regression model for ordinal and continuous variables. Patients with previous major amputation were excluded from this analysis. An insufficient number of events existed to develop a valid multivariant model. Chi-square analysis or Fisher's Exact Test (when the number of events was small) were used to compare clinical factors in patients treated with and without graft excision. Only the first graft of the patient with two graft infections was used in analyzing possible associations. Ap value less than 0.05 was considered statistically significant. All tests were two tailed. RESULTS The indication for femorodistal bypass grafting was claudication in 15 cases (38.5%) and limbthreatening ischemia in 19 (48.7%). Four patients (10.3%) had aneurysmal disease, and one (2.6%) underwent bypass at the time of excision of a soft tissue sarcoma. Twenty-seven of the infected grafts (69.2%) were expanded polytetrafluoroethylene (PTFE), six grafts (15.4%) were Dacron, four grafts (10.3%) were autologous saphen0us vein, and two grafts (5.1%) were composites of PTFE and vein. The type of graft material used at the time of the original procedure and the level of the proximal and distal anastomoses are detailed in Table I. Twelve patients had undergone previous aortofemoral bypass, and three patients underwent concomitant aortofemoral and femorodistal bypass. Three patients had proximal femorofemoral bypass, and one each had proximal iliofemoral or axiUofemoral bypass. Thirty-two of the 39 original bypass operations were performed in the presence of presumed systemic
lournal of VASCULAR SURGERY
or local risk factors for infection, most commonly previous groin operation or diabetes (Table II). Seven patients had documented infection at distant sites in the perioperative period (three urinary tract infections, one respiratory infection, and three soft tissue infections). Superficial wound infections developed in 11 patients after the initial procedure (6 proximal, 4 distal, and 1 both proximal and distal). The median time from placement of the femorodistal bypass to the initial symptom of graft infection was 48 days (range, 2 days to 8.8 years). Median time from graft placement to definitive treatment of the graft infection was 130 days (range, 20 days to 8.9 years). Nineteen grafts (49%) were occluded at the time they presented with infection. A localized collection of purulent material adjacent to the graft was the most common manifestation of infection, being present 51% of the time. Infected sinus tracts, ceUulitis involving the graft, and systemic sepsis were also relatively common (Table III). In 14 patients the diagnosis of graft infection was made on clinical grounds in the presence of cellulitis, infected sinus tracts, abscesses, or other signs of local infection. The remaining 25 patients underwent a total of 38 diagnostic procedures, most commonly CT scanning, ultrasonography, or white blood cell scans labeled with indium 111 (Table IV). In addition, 15 patients underwent angiography before definitive treatment of their graft infection. Graft infection was localized to the area of the proximal anastomosis in 17 cases (43.6%) and to the area of the distal anastomosis in 11 (28.2%). Seven patients (17.9%) had infection involving the entire graft. Two patients (5.1%) had isolated areas of infection involving a portion of the graft distant from both anastomotic sites, and two were infected at both anastomoses with an intervening uninvolved segment. Microbiologic cultures, obtained at the time of operation or by preoperative aspiration of localized collections, were positive in 35 of 39 cases (Table V). Eight patients had mixed bacteriology. Staphylococcus aureus was the most common pathogen (12 cases, 30.8%). Definitive treatment of the graft infections was divided into three groups: (1) excision of all or part of the infected graft without vascular reconstruction; (2) excision of the infected graft with vascular reconstruction; and (3) local treatment of the infected femorodistal bypass without graft excision, including drainage of localized collections, debridement of devitalized tissue, and, in some cases, rotation of muscle flaps for coverage.
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Infected femorodistal bypass and gra~ removal 297
Table I. Graft material and anastomotic sites Level of proximal anastomosis
Level of distal anastomosis
Material
No. ofgrafts
Prox bypassgraft
CFA
SFA
AIG"
BIG"
PTFE Dacron Composite Reversed vein Nonreversed vein In situ vein Total
27 6 2 2 1 _!1 39
15 4 0 0 0 _!1 20
11 1 2 1 0 0 15
1 1 0 1 1 0 4
9 4 0 1 0 _00 14
13 2 1 1 1 _!l 19
Tibial/peroneal 5 0 1 0 0 0 6
CFA, Comrnon femoral artery; SFA, superficial femoral artery; AKP, above-knee popliteal artery; BKP, below-knee popliteal artery.
G r o u p 1: Graft excision w i t h o u t vascular reconstruction (N = 19) Nineteen infected femorodistal bypass grafts were treated by partial (7) or total (12) graft excision without vascular reconstruction. Most anastomoses were at the common femoral level, whether to native artery or to graft in the groin area (Table I). After graft excision, those anastomoses were closed primarily or patched with vein or autogenous artery. When the proximal anastomosis was to the superficial femoral artery, that artery was ligated. Patent distal anastomotic sites were either patched or closed primarily. One patient also underwent transposition of the rectus femoris to cover the area of the graft excision. All of the grafts were prosthetic (4 Dacron, 15 PTFE), and 17 were occluded when they presented with infection. Infection of occluded grafts developed in seven patients in limbs previously amputated; these infections were significant rather than incidental and prompted hospitalization. Three of these patients presented with nonsalvageablc extremities, and four were judged to have nonreconstructible vessels. One patient underwent excision of a patent infected graft and above-knee amputation at the same: operation. Six of the remaining 11 limbs at risk within this treatment group required major amputations after excision of the infected graft. One of these amputations occurred in the other patient with a patent graft who suffered recurrent infection and subsequent death related to graft infection. G r o u p 2: Graft excision and arterial reconstruction (N = 9) Nine infected prosthetic femorodistal bypass grafts were treated by partial (7) or total (2) graft excision and femorodistal arterial reconstruction (Table VI). Seven of the grafts were patent; the two occluded grafts were associated with distal ischemia. In contrast to patients in group 1, all of these patients were thought to have salvageable extremities and
Table II. Local and systemic risk factors for graft infection
Previous groin operation Diabetes Obesity Concomitant minor amputation Malignancy Emergency operation Steroid use Groin irradiation
No. of,~rafts
(%)
25 15 5 5 3 3 2 1
(64.1) (38.5) (12.8) (12.8) (7.7) (7.7) (5.1) (2.6)
Table III. Presenting signs of infection
No. ofgrafts Abscess adjacent to graft 20 Infected sinus tract 15 Cellulitis 11 Systemic sepsis 8 Hemorrhage 4 Pseudoaneurysm 4 Graft exposure 4 Poor tissue incorporation 2 Acute arterial ischemia and graft thrombosis 1 Septic emboli 1
(%) (51.3) (38.5) (28.2) (20.5) (10.3) (10.3) (10.3) (5.1) (2.6) (2.6)
reconstructible vessels. Reconstruction was performed by extraanatomic routes (6) or with autogenous material (3). In one patient the rectus femoris was transposed to cover the new proximal anastomosis; this patient was the only infection related death within this group. The revision in this patient was an autogenous reconstruction. The patient, whose cultures grew Candida tropicalis, Klebdella oxytoca, and Staphylococcus epidermidis, developed recurrent infection of the native arteries with massive hemorrhage leading to amputation and death. There were three other recurrent graft infections, two of which were treated successfully. S. aureus infection developed in one man in both of his groin wounds after extraanatomic bypass grafting. These wounds
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Cherry et al.
TaMe IV. Tests initiated in diagnosis of graft infection (25 patients) Test
Positive Result
Negative Result
Equivocal Result
Total
9 5 4 2 0 0 1
2 2 1 1 1 1 0
6 1 2 0 0 0 0
i7 8 7 3 1 1 I
CT scan Indium WBC scan Ultrasonography Percutaneous aspiration MRI Gallium scan Sinogram
WBC, White blood cell; MRI, magnetic resonance imaging.
Table V. Bacteriology of femorodistal graft infection
Staphylococcus aureus Gram-negative bacilli (not pseudomonas organisms) Group D streptococci Coagulase-negative staphylococci Pseudomonas organisms Fungal pathogens Anaerobic pathogens Non-group D streptococci Others No growth
No. of cases
(%)
12 11
(30.8) (28.2)
5 4 3 3 3 2 3 4
(12.8) (10.3) (7.7) (7.7) (7.7) (5.1) (7.7) (10.3)
Eight patients (20.5%) had mukiple organisms.
were treated successfully with debridement and appropriate antibiotic coverage. S. epidermidis reinfection of the remaining PTFE graft in the groin developed in another patient. This was successfully removed. The third patient developed a recurrent S. aureus infection of an obturator bypass, which required amputation. In only four patients was treatment with excision and arterial reconstruction entirely successful, that is, with no incidence of reinfection, amputation, or loss of life. Group 3: Nonexcision of grafts (N = 11) Eleven patients with infected fcmorodistal bypasses were treated without excision of the infected graft (Table VII). Within this group were five prosthetic, four vein, and two composite (proximal PTFE, distal vein) grafts. All grafts were patent. Six of these patients had abscesses adjacent to the graft; primary treatment consisted of incision and drainage and local debridement of devitalized tissues. In addition, two patients were treated with open packing of the wound, and two had the proximal sartorius muscle transposed to cover the area of the graft infection. Two patients with infected sinus tracts were treated primarily with debridement; one
subsequently underwent a rectus femoris transposition. Two patients with signs of systemic sepsis and localized cellulitis were treated with debridement and either rectus femoris transposition (1) or open packing (i). The remaining patient in this group had an infected pseudoaneurysm and sinus tract; treatment consisted of pseudoaneurysm repair with an interposition Dacron graft between his Dacron aortofemoral bypass graft and his Dacron femoropopliteal bypass graft, wound and sinus tract debridement, and rectus femoris transposition. His cultures revealed no growth. One of the patients treated without graft excision died 3 months after operation of pulmonary complications. The graft was patent at the time of death. One sartorius muscle flap became necrotic but was debrided and successfully replaced with a rectus femoris flap. Two grafts developed late occlusions ( > 5 years after treatment of graft infection). One of these resulted in above-knee amputation. Neither had evidence of infection. The other eight grafts have been patent to latest follow-up, without signs of recurrent infection. Overall, treatment of the 39 infected femorodistal bypasses resulted in 3 related deaths, 11 amputations (32 limbs at risk), and 5 reinfections, as delineated by the summary of results by treatment group in Table VIII. The likelihood of developing any of these "poor outcomes" was increased in the presence of infection with coagulase-negative staphylococcus (p = 0.033) or fungal pathogens (p = 0.007) and in those patients in whom reconstruction with vein grafts after excision of the infected graft was part of their treatment (p = 0.024). Poor outcome was not associated with the primary use of a vein as the arterial conduit. Poor outcomes were less likely in patients whose original grafts were placed at this institution (p = 0.0362) and in those treated without graft excision (p = 0.007). In contrast, a number of variables were not associated with an adverse outcome (p > 0.05). These variables included gender,
Volume 15 Number 2 February 1992
Infected femorodistal bypass and graft removal 2 9 9
TaMe VI. Patients treated with graft excision and femorodistal reconstruction Type of graft
Type and location of infection
Portion of graft resected
PTFE
Abscess, distal anastomosis
Distal graft
PTFE
Abscess, hemorrhage, proximal anastomosis Sinus tract, cellulitis, proximal anastomosis Systemic sepsis, sinus tract, distal anastomosis
Proximal graft
Dacron PTFE PTFE
Infected pseudoaneurysm, proximal anastomosis Abscess, proximal anastomosis
PTFE PTFE PTFE PTFE
Proximal graft Distal graft Proximal graft Proximal graft
Infected pseudoaneurysm, proximal anastomosis Hemorrhage, exposed graft, proximal anastomosis
Proximal graft
Abscess, sinus tract, distal anastomosis
Entire graft
Entire graft
Method of reconstruction
Result
Femorodorsal pedal bypass (saphenous vein) Obturator bypass (Dacron) to retained distal graft Obturator bypass (Dacron) to retained distal graft Anterior tibial bypass (PTFE), via lateral tunnel, from proximal retained graft Axillopopliteal bypass (PTFE)
Recurrent infection in retained PTFE graft at 13 mo Doing well at 48 mo
Obturator bypass (PTFE) to retained distal graft Obturator bypass (PTFE) to retained distal graft Femoropopliteal bypass (saphenous vein), rectus femoris transposition Femorofemoral bypass (endartereetomized SFA) and femoropopliteal bypass (saphenous vein)
Doing well at 26 mo
Reinfection, graft occlusion, MZA at 19 mo Occlusion, AKA at 2 days Doing well at 42 mo
Doing well at 3 mo Reinfection, AICA, death at 25 days Reinfection at 30 days, treated with debridement, now doing well at 4 mo
Table VII. Patients treated without graft excision Type ofgraft
Type and location of infection
Treatment
PTFE
Systemic sepsis and cellulitis, proximal anastomosis
Multiple debridements, rectus femoris transposition
Vein
Infected sinus tract, proximal graft (not anastomotic) Abscess, distal anastomosis Abscess, proximal anastomosis
Debridement, rectus femoris transposition Incision and drainage Incision, drainage, debridement, sartorius muscle transposition Incision and drainage, packing Incision and drainage
PTFE Composite (prox PTFE distal vein) PTFE Vein
Abscess, distal anastomosis Abscess, distal anastomosis
Vein PTFE
Infected sinus tract, mid graft Systemic sepsis, cellulitis, distal anastomosis Abscess, distal anastomosis
Debridement Incision and drainage, packing
Composite (prox PTFE, distal vein)
Abscess, proximal anastomosis
Dacron
Infected pseudoaneurysm, sinus tract
Debridement, antibiotic irrigation, sartorius muscle transposition Repair, debridement, rectus femoris transposition
Vein
diabetes, previous groin operations, indication for the original operation, perioperative wound or distant infections, concomitant aortofemoral grafting, graft material, location of anastomoses, graft patency, presentation of infection (abscess versus cellulitis versus sinus tract), location of infection, and infection with S. a u r e u s or gram-negative bacilli. The results for the three different treatment groups, delineated by graft material, are presented in Table IX, and
Incision and drainage
Result Death from postoperative respiratory insufficiency at 3 mo (graft patent) Death from unrelated cause at 11 mo Doing well at 32 mo Necrosis of sartorius, salvage with rectus femoris transposition, doing well at 25 mo Doing well at 48 mo Death from unrelated cause at 21 mo Doing well at 32 mo Doing well at 5 mo Death from unrelated cause at 62 mo Occluded at 62 mo Occlusion, AICA at 76 mo
Kaplan-Meier probability curves of limb salvage and survival free of amputation and reinfection are presented in Figs. 1 and 2. Patients treated without graft excision had a significantly higher limb salvage rate (p = 0.012, log-rank test) than did those treated with partial or total graft excision. Differences in mortality and reinfection rates, when considered alone, were not significant. Patients treated without graft excision
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Cherry et al.
Table V I I I . Summary o f results by treatment group Treatment ofgraft infection
Group 1 Graft excisionwithout reconstruction Group 2 Graft excisionand femorodistalreconstruction Group 3 Local treatment without graft excision Total
Deaths related to graft infection
No. ofgrafts
Reinfection
Amputation
19
1
7
1
9
4
3
1
11 39
0 5
1 11
_1 3
Table IX. Results o f femorodistal graft infection, related to graft material and treatment No. ofgrafls and results of treatment Group 1 (graft excision)
Group 2 (graft excision and revascularization)
Vein
0
0
Composite (PTFE + vein)
0
0
Graft material
Dacron
PTFE
4 No reinfection,limb loss, or death from graft infection
i5 7 amputations 1 death
1 1 reinfection I amputation
8 3 reinfections 2 amputations 1 death
were more likely to have had their grafts placed at this institution (p -- 0.002), to have patent grafts (p = 0.00I), and to have vein grafts (p = 0.012). Although the time from graft placement to treatment o f graft infection tended to be shorter in this group, (median, 55 days versus 216 days), it did not reach statistical significance (p = 0.156 rank sum test). Numerous other variables o f demographics, presentation, and microbiology were not significantly different between the patients treated with and without graft excision.
DISCUSSION It seems paradoxic that nonexcisional therapy o f infected femorodistal grafts would yield a better limb salvage rate and similar reinfection and mortality rates as traditional excisional treatment, with or without reconstruction. Certainly the small number o f patients in this study and the variations o f
Group 3 (no graft excision)
4 No reinfection,limb loss, or death from graft infection 2 No reinfection,limb loss, or death from graft infection; 1 occlusion at 62 months, viable limb 1 No reinfection,limb loss or death from graft infection; i late occlusion (at 76 months); amputation; no evidenceof infection 4 i death at 3 months without evidence of graft infection
treatment offered make definitive conclusions impossible. The study was retrospective, and was undertaken because of the clinical impression that t h o s e patients whose infected grafts were not excised but were treated locally (albeit by a variety o f methods) seemed to have a better rate o f limb salvage. That impression was borne out. However, the groups were dissimilar in significant ways. The three groups o f patients reported on were so congregated in an attempt to bring some order to the comparison. At first we compared simply two groups, those having traditional excisional therapy and those not. H o w ever, the high number o f amputations in those patients having graft excision without reconstruction would have unfairly impugned conventional excision and reconstruction if the two groups were studied together. Many o f these patients, who were classified as group 1, presented with previous amputations or with nonviable (3) or nonreconstructible (4) extrem-
Volume 15 Number 2 February 1992
Infectedfemorodistal bypassand gra3~ removal 301 1.0 Group 3
0.8 0.6
2
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_--I
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0 0 Group 1 Graft excision without r(K;onstruction Group 2 Gra# excision with f~rnorodislai reconstruction Group, 3 NO graft excision
I
I
I
I
I
I
I
I
I
I
0.5
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1.5
2.0
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4
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3
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9
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1
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10
8
7
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4
3 CG- 13G~5~6-1B
Fig. 1. Kaplan Meier analysis of probability of limb salvage delineated by treatment group.
ities. The higher percentage of patients presenting with occlusion in this group (89.5%) as contrasted with the percentage of patients presenting with occlusion in group 2 (22.2%) and group 3 (0%) is striking evidence of the differences in the groups, the challenges posed, and in the expected outcomes. Further division of the groups into those with patent, stenotic, or occluded grafts would have been interesting. The small number of patients in these subsets and the different variables would have made these data uninterpretable. Our definition of reconstruction was restricted to that of redo of the primarily placed femoropopliteal or femorotibial graft. Profundaplasties were used in two patients in group 1 in fieu of redo femorodistal grafts with beneficial results. The patients in group 3 were treated for graft infection at a median interval of 55 days from graft placement, whereas the other two groups were treated at a median interval of 216 days. Although this difference was not statistically significant, we felt that it was of major clinical significance. Ehrenfeld (personal communication) has shown that early prosthetic groin infections can be well treated with meticulous local care and that there is steady advancement of granulation tissue over the infected prostheses. It may be that early infections are more easily handled by aggressive local measures than are late infections, which are well established in nonincorpo-
rated material. Timing of intervention may thus be a factor in determining the best treatment option. All patients with infected saphenous vein and composite grafts underwent nonexcisional treatment even when the prosthetic portion was involved in the infection. A sharp difference of opinion existed within our group concerning the merits of the two basic forms of therapy: resection or aggressive local treatment for infected prosthetic grafts. Nonexcisional therapy was probably offered more commonly to those patients with early infections. These patients were more often our own, perhaps making early detection and treatment more likely. Femorodistal grafts are probably more likely to be patent at the time of early intervention than at a later date, and that patency would contribute to an improved salvage rate, as seen in the patients in group 3. That the limb salvage rate is better in the group of patients treated without excision than in those treated traditionally is at first surprising, but on reflection a number of possible reasons emerge. (1) Patients admitted with occluded infected grafts are already relatively ischemic, tmlikely to undergo immediate revascularization in the face of infection, and therefore probably at higher risk for amputation. (2) The distal anastomotic site chosen at the initial grafting procedure is presumably the most advantageous. Repeat revascularization as treatment for graft infection must necessarily be done at sites removed
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Cherry et al.
1.0 Group 3
0.8
._z, "• = .O
0.6
2
0.4
Group 1 Group 2
n
0.2 0
0 Group 1 Graft excision without reconstruction Group 2 Graft excision with femorodistal reconstruction Group 3 No graft excision
0.5
1.0
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Years n = 10
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10
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3 ~ - 1300,.~00-~H9
Fig. 2. Kaplan Meier analysis of probability of survival free of recurrent infection or limb loss delineated by treatment group. from infection. The sites chosen for anastomoses are not as likely in these situations to be as anatomically or hemodynamically advantageous. (3) The use initially of prosthetic material implies an absent vein or one of poor quality. Prosthetic anastomoses to more distal sites remote from infection are not likely to have high patency rates. It is encouraging that the mortality rate did not increase with nonresectional treatment, which suggests that such therapy may be safely offered as a first option. If hemorrhage is a presenting symptom, and the graft is judged to be infected and not simply exposed and desiccated, excision is mandatory. In cases of overwhelming sepsis, excision may also be necessary. Less dramatic presenting symptoms, however, may allow a trial of aggressive local treatment rather than graft excision. The group from Montefiore Medical Center had excellent results treating infected, patent, nonbleeding grafts with aggressive local debridement. 9,12 Kwaan et al.8 reported excellent results using povidone-iodine suction irrigation systems. Transposition of muscle flaps has been reported by Mixter et al. 1° to work in 96% of cases. Our experience with infected aortofemoral grafts suggests that only 60% of these grafts so treated may be expected to heal. 13 On the other hand, rotational muscle flaps used in seven patients in the present series had only two failures, one of which was
salvaged with another muscle flap. The introduction of well-vascularized muscle into infected wounds reduces healing time and bacterial counts. These flaps may be better suited to femorodistal grafts than to aortofemoral grafts simply because the infected areas may be entirely encompassed and treated in the former and not in the latter. The wounds were prepared for the muscle by aggressive local care, especially debridement. When the wound appeared healthy and able to accept and support a muscle flap, transposition was carried out. This series lends support to all of these plans of nonresectional management. We have insufficient evidence to state that nonexdsional therapy is the treatment of choice for infected femorodistal bypass grafts. The study is retrospective, and there was no protocol for therapy. Decisions for treatment were made on clinical grounds by the individual staff surgeons and reflect the different preferences of each. We do, however, have strongly suggestive evidence that in the absence of hemorrhage and overwhelming sepsis, aggressive local management with drainage of localized collections, debridement of devitalized tissue, and drainage, packing, and/or rotational muscle flap coverage may provide superior limb salvage with the same reinfection and mortality rates as more conventional excisional therapy, with or without reconstruction.
Volume 15 Number 2 February 1992
Such nonresectional therapy represents a reasonable first step in the m a n a g e m e n t o f infected femorodistal grafts and provides a realistic expectation o f resolution o f the graft infection and salvage o f the limb w i t h o u t ~.e need for graft removal. REFERENCES i. SzilagyiDE, Smith RF, EUiott JP, Vrandecic MP. Infection in arterial reconstruction with synthetic grafts. Ann Surg 1972; 176:321..33. 2. Edwards WH Jr, Martin RS III, Jenkins JM, Edwards WH St, Mulherin JL Jr. Primary graft infections. J VAsc SURG 1987;6:235-9. 3. Johnson JA, Cogbill TH, Strutt PJ, Gundersen AL. Wound complications after infrainguinat bypass. Classification, predisposing factors, and management. Arch Surg 1988;123: 859-62. 4. Ehrenfeld WK, Wilbur BG, Olcott CN IV, Stoney RJ. Autogenous tissue reconstruction in the management of infected prosthetic grafts. Surgery 1979;85:82-92. 5. SeegerIM, Wheeler JR, Gregory RT, Snyder SO, Gayle RG. Autogenous graft replacement of infected prosthetic grafts in the femoral position. Surgery 1983;93:39-45. 6. LiekwegWG Jr, GreenfieldLL Vascular prosthetic infections: collected experience and results of treatment. Surgery 1977; 81:335-42.
Infected femorodistal bypass and graft removal 303
7. Carter SC, Cohen A, Whelan TJ. Clinical experience with management of the infected Dacron graft. Ann Surg I963; 158:249-55. 8. Kwaan JHM, Connolly JE. Successfulmanagement of prosthetic graft infection with continuous povidone-iodine irrigation. Arch Surg 1981;116:716-20. 9. Calligaro ICD, Veith FJ, Gupta SK, et al. A modified method for management of prosthetic graft infections involving an anastomosis to the common femoral artery. I VASC SURG 1990;11:485-92. 10. Mixter RC, Turnipseed WD, Smith DI Jr, Archer CW, Rao VK, Dibbell DG. Rotational muscle flaps: a new technique for covering infected vascular grafts. J VAsc SURG1989;9:472-8. 11. Meland NB, Arnold PG, Pairolero PC. Infected vascular prostheses: management with muscle transposition. (Submitted for publication). 12. Samson Rid, Veith FJ, Janko GS, Gupta SK, Scher LA. A modified classification and approach to the management of infections involving peripheral arterial prosthetic grafts. J VASCSFRG 1988;8:147-53. 13. Cherry 1<1Jr, Crepps IT Jr, Pairolero PC, et al. Abdominal aortic graft infections: management and tong-term outcome. Presented at the Thirteenth Annual Meeting of the Midwestern Vascular Surgical Society; September 29, 1989; Chicago, Ill. Submitted lmle 10, 1991; accepted Sept. 16, 1991.
DISCUSSION Dr. Jer~ T Goldstone (San Francisco, Calif.). According to the Random House Dictionary of the English language, "dogma" is defined as a specific tenet or doctrine authoritatively laid down, as by a church; or, a prescribed doctrine; or a settled or established opinion, belief, or principle. In this presentation, the authors have challenged the dogma that all infected prosthetic arterial grafts must be removed. Thirty-eight patients with 39 infected infrainguinal bypass grafts were the cohort for this presentation. The patients were divided into three groups based on whether or not the infected graft was excised and whether or not concominant femorodistal reconstruction was used. Overall, there was a 12.8% reinfection rate, a 32.2% rate of amputation of limbs at risk, and a 7.7% mortality rate. These results compare very favorably with those published by other experts dealing with similar patients. The surprising information presented today by Dr. Cherry was that although the reinfection and mortality rates between groups I, II, and III were the same, the limb salvage rate in the patients in whom the infected grafts were not excised was far better (90.9%) than in either of the other two groups where amputation rates were 54.5% and 33.3%. This has led the authors to conclude that nonresectional therapy represents a reasonable first step in the management of infected femoral distal grafts and provides a
realistic expectation for resolution of the graft infection and salvage of the limb without the need for graft removal. The most important question to be asked is whether the data support the conclusions. Certainly, as the authors point out, there is neither a sufficient number of patients nor sufficient evidence to state conclusively that nonexcisional therapy is the treatment of choice for infected femorodistal bypass grafts. I have several other comments, concerns, and questions to which I would like the authors to respond. The treatment groups were not similar. In group I, 17 of the 19 grafts were occluded. Seven of these were in limbs with previous amputation but 11 other limbs were at least potentially reconstructible, and yet, no reconstructions were attempted. Why not? In group II, 7 of the 9 grafts were patent, and in group III, all of the grafts were patent. As Dr. Cherry has pointed out, no standard treatment protocol existed for these infections. Treatment decisions were made on clinical grounds by individual surgeons based on their own preferences. It was of particular interest to me that 6 of the 11 grafts in the nonexcisional treatment group were surrounded by an abscess, and these apparently did well with incision, drainage, and local treatment. In the statistical analysis, bad outcomes were significantly related to infections with S. epidermidis and the
304
Cherry et al.
presence of saphenous vein as the infected graft. I would have predicted that these two factors would be associated with a more favorable outcome since S. epidermidis is relatively less virulent than many of the other organisms cultured from the graft infections in this series, and since autogenous tissue, that is vein, is known to have better healing potential in the presence of infection than do prosthetics. Do the authors have an explanation for this? The median time from graft implantation to treatment of the subsequent infection was 55 days for the nonexcised grafts and 216 days for the grafts that were excised. Although this difference of 161 days was not statistically significant, it seems to me to be clinically significant, suggesting that if nonexcisional therapy is appropriate, it may be so for early rather than late graft infections. Similarly, patients who received their initial grafting operation at the Mayo Clinic were more likely to have their graft infections treated by nonexcisional therapy. Does this represent treatment bias favoring their own patients, or is there some other explanation for this trend? The authors claim that one of the reasons for the high amputation rate in the reconstructed patients is that the original grafts were performed at the most advantageous distal anastomotic site, and therefore to treat the ischemia less advantageous anastomotic sites needed to be selected. Based on my own experience, I disagree. Many of the patients that we see at our tertiary referral center have had their distal anastomoses made at the most convenient rather than the most advantageous location. These comments and concerns notwithstanding, I concur with the authors' conclusions that nonresectional therapy, as described in their presentation, represents a reasonable first step in the management of infected femoral distal grafts. It certainly will work in some patients. In stating this however, it must be emphasized that the authors followed sound surgical principles in the treatment of these patients, namely drainage of localized collections, debridement of devitalized tissues, and increase in local blood supply by the use of rotational muscle flaps. Readers of this article should be warned, however, that although rotational muscle flaps are attractive and may be helpful, they are not a panacea. They failed in two of seven patients (28.6%) in the present series, and we have had several failures in our own experience. Finally, nonexcisional treatment of prosthetic graft infections should be applied very cautiously if at all to infections elsewhere, particularly those involving an aortic prosthesis. Dr. Kenneth Cherry. You are right, they were indeed different groups, and I tried to make that dear. The first group, the group treated without excision, had infected, occluded, prosthetic grafts. Many of these patients had nonviable or nonreconstructible extremities on presentation, but some of those limbs that were not reconstructed were thought to be viable. Obviously that proved not to be true for all. In some the infection was so widespread that to reconstruct it in that situation would probably have risked the patient's life more than it would have given him a chance of salvaging the limb.
Journal of VASCULAR SURGERY
Yes, I think that the differences in presentation are indeed responsible for the surgeons' selection of treatment, just as in the examples we talked about. Certainly with a patent saphenous vein graft, I think everyone felt that they could make the effort to save that and have a realistic expectation that it would work. The controversy was over what to do with patent infected prosthetic grafts. As to the question about why infections with S. epidermidis had a poor outcome, we can only surmise that these are indolent slow infections and that the graft infections may have presented at a later more advanced stage. The vein associated with poor outcome is that vein used in treating the infection as an autogenous reconstruction, not vein used initially. There were three of these used and it simply did not work well. We think that is because these veins were of poor quality, which is why the prosthetics had been chosen in the first place. We agree with you that earlier infections are better treated by aggressive local therapy than are late infections. We think that is one of the reasons our own patients may have done better in that they perhaps were diagnosed earlier. We also agree that the muscle flaps are not a panacea and the area must undergo aggressive debridement and standard surgical treatment to ready the area to receive the musde flap. We, too, have found that it does not work as well for aortic grafts, and we think it is simply because the extent of the aortic graft cannot be well encompassed by a rotational muscle flap. Dr. Frank Veith (New York, N.Y.). We have had a 19-year experience with graft-saving treatment for infected lower extremity prosthetic grafts and have developed a new classification system to facilitate this nonexcisional treatment. On the basis of this experience, now twice published in the JOURNALOF VASCULAR SURGERY, we concur with the authors' conclusions. In our series of more than 45 infected prosthetic peripheral grafts, all or a portion of the graft could be salvaged successfully in 75% of cases if anastomotic breakdown had not occurred. Our follow-up with these successes now extends to 19 years. However, 25% of our efforts ended in failure, either anastomotic breakdown with bleeding or failure of the wound to heal. We have been unable to predict these failures at the outset, and I would like to ask the authors if they have criteria other than anastomotic breakdown for determining when graft-saving treatment, such as they and we have advocated, will not work. Dr. John Connolly (Irvine, Calif.). As Dr. Cherry mentioned, Dr. Kwaan and I over 10 years ago published a paper in which we showed that infected prosthetic grafts in the groin could be managed by early conservative treatment in some selected patients. These cases were groin infections in patent aortofemoral grafts where infection is even more potentially disastrous, as you know, than in the leg. However, the modallties that we used successfully in that small series of cases are similarly applied to the leg.
V o l ~ e ig Number 2 February 1992
Infected femorodistal bypassand graft removal 305
I have found over the years that a patent infected saphenous vein bypass in the lower extremity that gets infected, can be successfully treated by open drainage and proper antibiotics, because we are dealing with autogenous tissue. Prosthetic graft infection, however, is much more difficult to handle. If it is an infected femoropopliteal bypass or femorodistal bypass, and is occluded, we would remove the graft and reconstruct later. If it is a patent functioning graft where the viability of the foot is dependent on the bypass we would try drainage, debridement, appropriate antibiotics, continuous povodoneiodine administration. Secondary closure or muscle rotation would be performed only after the wound is sterile. If we cannot sterilize the wound, we would then remove the graft. When we reported our series over 10 years ago, the only things that were new in it were the use of continuous povodone iodine and muscle rotation. I would like to ask the authors if they have used povodone-iodine and if they thought it could improve their results. Obviously conservative management is not a panacea, but is something that I think is worth trying in desperate cases where the graft is infected and the leg is dependent on it and it will be necessary to revascularize if the graft is taken OUt.
The other thing that I would like to stress is to remember that if you do successfully treat such a patient, infection can occur even years later, and therefore we instruct the patient carefully to return to us at the first sign of fever, redness, or malaise that might lead us to believe that recurrent infection is occurring. Dr. William Turnipseed (Madison, Wis.). I strongly
support the idea that a fimctional and patent graft with structurally intact anastomoses in many cases can be saved. Our experience has been that if you cannot completely excise the pseudosheath around the graft that it becomes a locus for bacterial hiding, and that is one of the causes for failure. Are there circumstances where you might consider a modification of your technique and cut out segments of the graft to put in a clean piece and then cover it? We have concluded from our experience that if you can preserve the collateral system through the deep femoral artery or through the hypogastric vessels when you remove a functional graft, many of these limbs although ischemic will in fact survive. Do you have any commentary on that? Dr. Cherry. I will answer Dr. Veith's questions first. First of all, we appreciate his comments, and his work helped prompt this study. I do not think that we do know how to predict which ones will fail, Dr. Veith. Whether those predictors of poor outcome that we found in this small group of patients will hold up in a larger group or not I just do not know. To answer Dr. Connolly's questions, yes, some of the patients did have povodone-iodine irrigation and we do not hesitate to use that if it looks as if it would help. Just as you said, treatment of the patent infected prosthetic graft is more of a dilemma than the autogenous graft. We agree with Dr. Turnipseed that the pseudosheath does need to be excised, that you do have to have a clean bed for muscular flaps to work. Some partial excisions were done. We included those in the excisional group. We also agree that the hypogastric and deep circulations can salvage a leg that otherwise might be lost.
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