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Management of primary aortic graft infection by extra-anatomic bypass reconstruction
Eur J Vasc Surg 7, 301-307 (1993)
Management of Primary Aortic Graft Infection by Extra-anatomic Bypass Reconstruction* Thomas Lehnert, Hans-Peter Gruber, Norbert Maeder and Jens-Rainer Allenberg Department of Surgery, University of Heidelberg, Germany In this retrospective study, 21 patients requiring treatment for primary infection of an aortic prosthesis between 1981 and 1991 were identified from a prospective register. Ten of the 21 patients had had additional peripheral reconstructive vascular surgery before the diagnosis qt'aortic graft infection. The median interval between aortic graft insertion and diagnosis of graft infection was 16 months (range 1-84). Infected grafts were removed and an extra-anatomic bypass constructed in all patients. All but three patients had axillodistal reconstruction. Six patients had simultaneous operations, whilst the other 15 patients had a staged procedure with extra-anatomic reconstruction preceding graft removal. Two patients died before discharge from the hospital (9.5%). No patient required extremity amputation in the perioperative period. By life-table analysis patient survival (including perioperative deaths) was 80 % at I year, 55 % at 3 years and 40 % at 5 years. Primary graft patency was 62 % at 1 year, 51% at 3 years and 40% at 5 years. Limb salvage rate was 89% at 1 year, 63% at 3 years and 63% at 5 years. The median length of follow-up was 24 months. Extra-anatomic reconstruction in patients with aortic graft infection can be performed with low perioperative mortality. Limb salvage rates following extra-anatomic reconstruction are determined not only by the mode of reconstruction, but also by the primary disease. Key Words: Aorta; Graft replacement; Infection; Extra-anatomic bypass.
Introduction Infection of vascular prostheses represents the most troublesome postoperative complication in reconstructive vascular surgery. In patients with aortic prostheses primary graft infection is a life threatening complication. Early reports have recorded a mortality of more than 40%.1-3 A literature review of the past decade indicates that mortality of these patients still may exceed 20% (Table 1) and primary amputation rates may be as high as 31%. Several recent reports have indicated that orthotopic reconstruction, following removal of an infected aortic graft may be preferable to the standard extra-anatomic reconstruction. 11,12 Considering this new approach for our own treatment policy prompted us to review our depart-
ment's experience with the treatment of primary infected aortic prostheses.
Methods
In a retrospective study we examined 21 patients treated at the Department of Surgery, University of Heidelberg, Germany, for primary infection of aortic grafts during the 11 year period 1981-1991. Patients were identified from a prospective register of all patients undergoing arterial surgery. Patients with primary aortic infection, mycotic aneurysm, aortoenteric fistula or graft-enteric fistula were excluded from the study. Clinical data were extracted from hospital records which were available for all 21 patients. Mortality included all hospital deaths before discharge of the patient. Follow-up information was also obtained from hospital records and by contacting the patients * Presented at the 8th Annual Meeting of the German Society for and/or their local physicians. Follow-up information Vascular Surgery, Dresden, Germany, May 1992. could be obtained for all patients. Postoperative surPlease address all correspondence to: PD Dr Thomas Lehnert, Department of Surgery, University of Heidelberg, Im Neuen- vival, primary graft patency and limb salvage rates were calculated by the life-table method. 13 heimer Feld 110, D-6900 Heidelberg, Germany. 0950-821X/93/070301+07 $08.00/0© 1993Grune & Stratton Ltd.
302
T. Lehnert e t al.
Table 1. P r i m a r y aortic g r a f t i n f e c t i o n p e r i o p e r a t i v e m o r t a l i t y
Author
Reference
Number of cases
Year
Mortality (%)
Comment
Szilagyi
(1)
1972
17
7 (41%)
Bunt
(2)
1983
105
29 (28%)
review
Trout
(3)
1984
37
16 (43%)
review
Fulenwider
(4)
1983
11
0 (0%)
O'Hara
(5)
1986
51
7 (14%)
30 days
Reilly
(6)
1987
58
8 (14%)
30 days
Edwards
(7)
1988
16
3 (19%)
Yeager
(8)
1990
23
5 (22%)
Ricotta
(9)
1991
24
5 (21%)
(10)
1992
7
2 (29%)
1992
21
2 (10%)
Olah Present series
Results The m e a n age of the 21 patients (three w o m e n a n d 18 m e n ) w a s 62 (_+9) y e a r s at the time graft infection was diagnosed.
the diagnosis of graft infection w a s 16 m o n t h s (range 1-84). In s e v e n patients (33%) graft infection w a s d i a g n o s e d w i t h i n 6 m o n t h s of the p r i m a r y o p e r a t i o n a n d in three p a t i e n t s (14%) the time interval b e t w e e n the p r i m a r y o p e r a t i o n a n d diagnosis of graft infection e x c e e d e d 5 years (Fig. 1). 100
Primary aortic grafting Sixteen of the 21 patients w e r e initially treated at this d e p a r t m e n t , while five patients (24%) h a d their prim a r y o p e r a t i o n at o t h e r hospitals. P r i m a r y aortic surg e r y w a s p e r f o r m e d for aortoiliac occlusive disease in 17 patients a n d for a n infrarenal aortic a n e u r y s m in four patients. Peripheral i s c h a e m i a w a s classified according to Fontaine as stage I (n = 2), stage lib (n = 6), stage III (n = 6) a n d stage IV (n = 7). Aortodistal bifurcation grafts w e r e placed in 15 patients. Six patients h a d unilateral a o r t o f e m o r a l reconstruction w i t h p e r i p h e r a l a n a s t o m o s e s at the level of the c o m m o n (n = 4) or d e e p f e m o r a l (n = 2) artery. All unilateral reconstructions w e r e p e r f o r m e d for occlusive disease. In 19 patients the distal a n a s t o m o s i s w a s at the femoral or popliteal level (90%) a n d only two patients h a d aortic grafts w i t h the distal a n a s t o m o s e s to the iliac arteries.
Time to infection The m e d i a n time interval b e t w e e n initial s u r g e r y a n d Eur J Vasc Surg Vol 7, May 1993
/ -
20
8015
r~
60 © ..~
40
E
20
0
/ I
P) 10
E
Z 5
1
1
I
I
2
i
I
3
i
t
4
i
I
5
i
I
6
i
7
0
Years Fig. 1. Time interval between primary aortic graft replacement and diagnosis of graft infection.
Causes of graft infection Precise d e t e r m i n a t i o n of the cause of graft infection w a s difficult, if not impossible in m o s t patients. In the p r e s e n t series graft infection m a y h a v e b e e n related to p r e v i o u s vascular s u r g e r y involving the site of the distal a n a s t o m o s i s of s u b s e q u e n t aortic reconstruc-
Bypass of Infected Aortic Grafts
tion in four patients. Five patients had perioperative complications during the initial surgery and six patients had had additional vascular surgery involving the site of the distal anastomosis of the aortic graft prior to the diagnosis of infection (Table 2). Three Table 2. Possible causes of graft infection
Possible cause
Total
Vascular operations before aortic grafting
4
Perioperative complications of aortic grafting
5
Haematoma requiring evacuation
2
Bypass thrombectomy
1
Small bowel perforation
1
Inguinal lymphocele
1
303
Table 3. Microbiological studies
Total Gram-positive bacteria Staphylococcus epidermidis
7
Corynebacteria
6
Staphylococcus aureus
5
Enterococcus
4
Haemolytic streptococcus
3
Acinetobacter
1
Citrobacter
1
Peptostreptococcus spp.
1
Gram-negative bacteria Pseudomonas spp.
3
Subsequent vascular operations
6
Escherichia coli
2
Later infectious complications
3
Bacteroides
1
Ischaemic colitis
1
Proteus spp.
1
Diverticulitis/abscess formation
1
Serratia spp.
1
Inguinal lymph node abscess
1
Candida spp.
4
3
Negative
2
Missing
4
'Unexplained'
patients had later complications not directly involving the vascular graft and in three patients no clinical event was noted that could have served to explain the graft infection.
Microbiologic studies Cultures taken from the site of infection revealed the presence of Gram-positive bacteria and in the majority of these cases staphylococci were demonstrable (Table 3). In four patients candida species were found and in one this was the only organism demonstrable. Sterile cultures were obtained in two patients. It should be noted, however, that due to the retrospective nature of this analysis, bacteriological studies were not performed according to a standardised protocol and the information is almost certainly incomplete. 14
taneously, because graft infection was complicated by bleeding (n = 3) or septicaemia (n = 3) requiring immediate surgical treatment. In the other 15 patients the extra-anatomic bypass was inserted first, followed approximately 1 week later by removal of the infected graft material. The rationale for the staged procedure was to reduce operative stress, ensure adequate perfusion and possibly reduce the risk of infection of the extra-anatomic graft. All reconstructions were extra-anatomic and in all but three patients a n axillo-distal bypass was inserted. Three patients had other procedures: thoracofemoral bypass because of bilateral subclavian artery stenoses, femorofemoral crossover bypass for unilateral graft infection and lateral transosseous iliacopopliteal bypass for localised infection involving only the distal portion of the aortic graft. Whenever possible the aortic stump and the site of the infected graft were covered with omentum.
Vascular reconstruction and bypass explanation Perioperative complications and causes of death All patients had the infected graft material removed. In six patients reconstruction was performed simul-
The most serious perioperative complication of graft Eur J Vasc Surg Vol 7, May 1993
T. Lehnert et al.
304
removal was injury to the ureters which was recorded in three patients. In two patients injury was diagnosed intraoperatively and treated by suture and temporary stenting. In one patient the ureteral lesion was diagnosed only postoperatively and this injury was treated by temporary stenting alone. This patient had a very stormy time, but eventually recovered. Twelve months later, however, she presented with reinfection of the extra-anatomic graft (see below). Other complications included bleeding (n = 2), ileus (n = 1), persistent/recurrent groin infection (n = 5), retroperitoneal abscess (n = 1), small bowel perforation (n = 1) and ischaemia of the sigmoid colon (n = 1). Two patients died perioperatively. One patient had a reticulum cell sarcoma which was not diagnosed until the time of graft removal. This patient died of cachexia. The patient with colonic ischaemia had a left hemicolectomy for perforation of the sigmoid colon and eventually died of multiple organ failure.
Follow-up All patients were followed for a median interval of 24 months. Life-table analysis of primary extra-anatomic bypass patency rates is given in Fig. 2. Nine out of 17
100 80
e-
(2)
(1)
40 20 I
0
1
I
2
I
3 Years
I
4
I
5
6
Fig. 3. Life-table analysis of limb salvage rates following extraanatomic bypass reconstruction for primary aortic graft infection. Patients at risk are in parenthesis. Vertical bars indicate standard deviation.
primary aortic graft was inserted for aortoiliac occlusive disease. No patient with aneurysmal disease required amputation. Nine patients died during follow-up in addition to two perioperative deaths (eight out of 17 patients with occlusive disease and three out of four patients with aneurysmal disease). Three year survival determined by life-table analysis was 55% (Fig. 4). Causes of death were cardiopul100
80
80
8
I
(4)
~D
100
60
60 -
,fi 60
8P~ (11)
(11)
¢~ 40
40
(3)
(2)
(1)
(1)
20 I
I
]
1
2
3
q
I
I
I
4 5 6 7 Years Fig. 2. Life-table analysis of primary bypass patency following extra-anatomic reconstruction for primary aortic graft infection. Patients at risk are in parenthesis. Vertical bars indicate standard deviation.
patients with occlusive disease required subsequent bypass thrombectomy 0.5-32 months after extra-anatomic reconstruction compared to one of four patients with aneurysmal disease, 4 months postoperatively. Secondary extremity amputations were necessary in five patients 3-27 months after revascularisation (median 12 months; Fig. 3). In all these patients the Eur J Vasc Surg Vol 7, May 1993
(4)
(2)
(1)
(1)
20 I
I
t
I
I
I
I
1
2
3
4 Years
5
6
7
8
Fig. 4. Life-table analysis of postoperative survival following extraanatomic bypass reconstruction for primary aortic graft infection. Fwo postoperative deaths are included. Patients at risk are in parenthesis. Vertical bars indicate standard deviation.
monary insufficiency (n = 3), upper gastrointestinal bleeding (n = 1), unknown (n = 3) and cachexia (n = 2). One patient with occlusive disease had reinfection of the extra-anatomic bypass 12 months later. This patient died postoperatively following removal of the infected extra-anatomic graft and insertion of a new extra-anatomic bypass. The cause of death was myocardial insufficiency at a time when the infection was controlled. In terms of survival, limb salvage or pri-
Bypass of Infected Aortic Grafts
mary graft patency, no valid comparison of simultaneous versus staged operations was possible because treatment was not randomised and the numbers were small, however, no obvious differences were noted between the two groups.
Discussion
Graft infection may only become apparent several years after aortic bypass grafting. The true incidence of graft infection following prosthetic replacement of the aorta is therefore ill defined. A survey of the more recent literature comprising over 4000 patients indicates that approximately 0.3% of all aortoiliac procedures are performed for aortic graft infection. It appears that the risk of infection increases with distal placement of the peripheral anastomosis. If the distal anastomosis is placed at the femoral artery level, the incidence of infection may be four times higher than with iliac anastomosis. 1,5,1s-is Causes for graft infection are similarly difficult to establish. Experimental studies have demonstrated the ability of intestinal bacteria to translocate to intraperitoneal prosthetic material. 19 Diligent microbiological studies of macroscopically non-infected graft material removed for graft thrombosis or anastomotic aneurysm have revealed the presence of microorganisms in 79% of cases. 2° Other studies have demonstrated the presence of bacteria in thrombotic material of aortic aneurysms in up to 31% of patients 2~-24 and microorganisms were demonstrable in 47% of diseased arterial vessels in the absence of overt infection. 25 In the present series more than half of the patients had repeated operations in the same vascular region or infectious complications during previous procedures. Others have also noted that patients with aortic graft infection were more likely to have had repeated vascular surgery in the same region or required reoperation for local complications particularly in the groin during the first aortic operation. 7, 9, 26,27 Aortic graft infection is particularly dangerous if there is bleeding from the proximal anastomosis or generalised sepsis. In addition, graft occlusion may result in distal ischaemia. The reported mortality of primary aortic graft infection may exceed 40% (Table 1) with primary amputation rates of up to 43% depending on the type of reconstruction. 6 Individual reports have indicated good results of local irrigation treatment using povidone-iodine 28'29 or antibiotics.3° However, reinfection with a fatal o u t -
305
come has been described 3° and follow-up of asymptomatic patients is only limited. It is also possible that such cases with an unfavourable outcome have n o t been reported in the literature. To date it would seem that this form of treatment should be reserved for patients w h o are unfit to sustain major surgery. The standard procedure for aortic graft infection includes removal of the infected prosthesis, local debridement and extra-anatomic reconstruction. 31 Graft removal and vascular reconstruction may be performed simultaneously or as a staged procedure. Some authors prefer to remove the infected prosthesis first and then perform vascular reconstruction at a later stage. 5'26 Others prefer to perform the extraanatomic reconstruction under antibiotic cover prior to removal of the infected graft at a second operation approximately 1 week later. 1,3, 6-9, 31 Whenever possible the aortic stump and the infected area should be covered with omentum. There was no obvious difference between our staged (n = 15) and simultaneous (n = 6) procedures in terms of postoperative mortality or morbidity. One patient with simultaneous bypass excision and extra-anatomic regrafting developed reinfection of the new bypass. No graft reinfection was recorded in patients with staged procedures. Other reports confirm that insertion of an extra-anatomic bypass prior to removal of the infected aortic graft carries little risk of reinfection 3"7 and lower amputation rates and mortality have been reported after staged operations than after simultaneous procedures. 6 Although to date the superiority of staged operations has not been proven by a strictly prospective and randomised study, we would concur that, where possible, a staged procedure with revascularisation followed by removal of infected graft material is likely to yield the best results. The limb salvage rate following extra-anatomic reconstruction for aortic sepsis has been previously reported as 75% at 3 years 3s and was 63% in our series. Long-term extremity preservation, however, will be determined not only by the method of reconstruction, but also by the primary disease. In the majority of patients in our series the primary operation was performed for aortoiliac occlusive disease. Progressive arterial occlusive disease rather than poor extra-anatomic bypass function may be critical for long-term limb preservation. All five extremity amputations in this series were necessary in patients in which the primary aortic graft was placed for arterial occlusive disease. In contrast, extremities could be preserved in all patients with aneurysmal disease following extra-anatomic reconstruction. Similarly, more than half of the patients with occlusive disease required bypass thrombectomy during follow-up, as Eur J VascSurg Vol 7, May 1993
306
T. Lehnert et aL
compared to only one of four patients with aneurysmal disease. These findings support previous observations indicating a higher risk of extra-anatomic bypass thrombosis in patients with occlusive disease. 38 Recently, several reports have indicated favourable results for in situ (orthotopic) aortic reconstruction. The rationale for in situ replacement is to avoid aortic stump blow out as well as ascending thrombosis of the aorta, and possibly to improve extremity perfusion. In situ replacement of the aorta has been employed for patients with primary aortic infection, mycotic aneurysm of the aorta and aorto(graft)enteric f i s t u l a e . 11'12"32-35 A review of the literature revealed that the mortality of in situ reconstruction for aortoenteric graft infection was 56% in 66 patients studied between 1958-1981. 36 In a more recent review covering the period 1980-1989, the perioperative mortality was 37% in 82 patients. 33 Experience with in situ aortic replacement for primary infection of aortic grafts (without concomitant aortoenteric fistula) is very limited. 37 The perioperative mortality of 11 patients with suspected primary aortic graft infection w h o received an in situ aortic graft replacement was reported as only 9%. However, infection of the excised graft was only proven in one patient, who subsequently died. In the other 10 patients, neither blood cultures nor specimens from the infected area revealed any bacterial growth and these patients may have had a perigraft reaction rather than infection. The true significance of this report is even more difficult to establish since the same group has previously reported data from the same time period with significant complications during follow-up which were not referred to in the more recent report (see below). 11 The risk of aortic stump blow out is, by definition, excluded after in situ reconstruction. However, disruption of the proximal anastomosis with fatal haemorrhage has been reported in over 10% of patients with in situ replacement of infected aortic grafts. 11 This may be caused by persistent infection in the retroperitoneal space maintained by the presence of prosthetic graft material. It is possible that fatal bleeding complications from the proximal anastomosis following in situ repair of primary aortic graft infection will be more frequent than aortic stump rupture after extra-anatomic reconstruction. A multi-staged procedure has been used as an alternative approach, in which initial arterial reconstruction was achieved by extra-anatomic bypass. 4'39 At a later stage when the retroperitoneal infection has definitely healed this may be replaced by an aortic in situ graft. As a planned approach this has however Eur J Vasc Surg Vol 7, May 1993
been found to be impractical for the majority of patients. 10 The role of in situ aortic replacement in patients with primary aortic graft infection has yet to be defined particularly with regard to long-term complication rates. It would seem that to date there is not sufficient evidence to abandon extra-anatomic bypass reconstruction for patients with infected aortic grafts.
References 1 SZILAGYIDE, SMITHRF, ELLIOTTJP, VRANDECICMP. Infection in arterial reconstruction with synthetic grafts. Ann Surg 1972; 176: 321-333. 2 BUNTTJ. Synthetic vascular graft infections. I. Graft infections. Surgery 1983; 93: 733-746. 3 TROUTHH, KOZLOFFL, GIORDANOJM. Priority of revascularization in patients with graft enteric fistulas, infected arteries, or infected arterial prosthesis. Ann Surg 1984; 199: 669-683. 4 FULENWlOERJT, SMITH RB, JOHNSONRW, JOHNSONRC, SALAM AA, PERDUE GD. Reoperative abdominal arterial surgery--a ten-year experience. Surgery 1983; 93: 20-27. 5 0 ' H A R A PJ, HERTZER NR, BEVEN EG, KRAIEWSKILP. Surgical management of infected abdominal aortic grafts: a review of 25year experience. J Vasc Surg 1986; 3: 725-731. 6 REILLYLM, STONEYRJ, GOLDSTONEJ, EHRENFELDWK. Improved management of aortic graft infection: the influence of operation sequence and staging. J Vasc Surg 1987; 5: 421-431. 7 EDWARDSMJ, RICHARDSONJD,KLAMERTW.Management of aortic prosthetic infections. Am J Surg 1988; 155: 327-330. 8 YEAGERRA, MONETAGL, TAYLORLM, HARRISEJ, McCONNELL MB, PORTER JM. Improving survival and limb salvage in patients with aortic graft infection. Am J Surg 1990; 159: 466469. 9 RICOTTAJJ, FAGGIOLIGL, STELLAA, CURLGR, PEER R, UPSONJ, D'ADDATO M, ANAIN J, GUTIERREZI. Total excision and extraanatomic bypass for aortic graft infection. Am J Surg 1991; 162: 145-149. 10 OLAH A, VOGT M, LASKEA, CARRELLT, BAUERE, TURINA M. Axillo-femoral bypass and simultaneous removal of the aortofemoral vascular infection site: is the procedure safe? Eur J Vasc Surg 1992; 6: 252-254. 11 WALKERWE, COOLEYDA, DUNCANJM, HALLMANGL, OTT DA, REUL GJ. The management of aortoduodenal fistula by in situ replacement of the infected abdominal aortic graft. Ann Surg 1987; 205: 727-732. 12 CHANFY, CRAWFORDES, COSELLIJS, SAFIHJ, WILLIAMSTW. In situ prosthetic graft replacement for mycotic aneurysm of the aorta. Ann Thorac Surg 1989; 47: 193-203. 13 CUTLER SJ, EDERER F. Maximum utilization of the life table method in analyzing survival. J Chron Dis 1958; 8: 699-712. 14 BERGAMINITM, BANDYKDF, GOVOSTIOSD, VETSCHR, TOWNEJB. Identification of Staphylococcus epidermidis vascular graft infections: a comparison of culture techniques. J Vasc Surg 1989; 9: 665-670. 15 GOLDSTONEJ, MOORE WS. Infection in vascular prosthesis: clinical manifestations and surgical management. Am J Surg 1974; 128: 225-233. 16 LORENTZENJE, NIELSENON, ARENDRUPH, KIMOSEHH, BILLES, ANDERSENJ, JENSENCH, JACOBSENF, RODEROC. Vascular graft infection: an analysis of sixty-two graft infections in 2411 consecutively implanted synthetic vascular grafts. Surgery 1985; 98: 81-86. 17 EDWARDSWH, MARTIN RS, JENKINSJM, EDWARDSWH, MULHERIN JL. Primary graft infections. J Vasc Surg 1987; 6: 235-239. 18 JOHNSTONKW. Multicenter prospective study of nonruptured
Bypass of Infected Aortic Grafts
19 20 21 22
23 24
25
26 27 28
abdominal aortic aneurysm. Part II. Variables predicting morbidity and mortality. J Vasc Surg 1989; 9: 437-447. MORA EM, CARDONA MA, SIMMONS RL. Enteric bacteria and ingested inert particles translocate to intraperitoneal prosthetic materials. Arch Surg 1991; 126: 157-163. KAEBNICK HW, BANDYK DF, BERGAMINI TW, TOWNE JB. The microbiology of explanted vascular prostheses. Surgery 1987; 102: 756-762. McAuLEY CE, STEED DL, WEBSTER MW. Bacterial presence in aortic thrombus at elective aneurysm resection: is it clinically significant? Am J Surg 1984; 147: 322-324. ERNST CB, CAMPBELL HC, DAUGHERTY ME, SACHATELLO CR, GRIFFEN WO. Incidence a n d significance of intra-operative bacterial cultures during abdominal aortic aneurysmectomy. Ann Surg 1977; 185: 626-633. ILGENFRITZFM, JORDAN FT. Microbiological monitoring of aortic aneurysm wall and contents during aneurysmectomy. Arch Surg 1988; 123: 506-508. BRANDIMARTEC, SANTINI C, VENDITTIM, BArOCCHIP, SERRAP, GALLO P, D'AMATI G, RIZZO L, SPEZIALEF, FIORANI P. Clinical significance of intraoperative cultures of aneurysm walls and contents in elective abdominal aortic aneurysmectomy. Eur J Epidemiol 1989; 5: 521-525. MACBETH GA, RUBIN JR, MCINTYRE KE, GOLDSTONEJ, MALONE MA. The relevance of arterial wall microbiology to the treatment of prosthetic graft infections: graft infection vs. arterial infection. J Vasc Surg 1984; 1: 750-756. TURNIPSEEDWD, BERKOFFHA, DETMER DE, ACHER CW, BELZER FO. Arterial graft infections. Delayed vs. immediate vascular reconstruction. Arch Surg 1983; 118: 410-414. MARTIN-PAREDERO V, BUSUTTIL RW, DIXON SM, BAKER JD, MACHLEDER H, MOORE WS. Fate of aortic graft removal. Am J Surg 1983; 146: 194-197. KNIGHTCD, FARNELLMB, HOLLIER LH. Treatment of aortic graft
29 30 31 32 33 34 35 36 37 38 39
307
infection with Povidone-Iodine irrigation. Mayo Clin Proc 1983; 58: 472-475. KWAAN JHM, CONNOLLY JE. Successful management of prosthetic graft infection with continuous povidone-iodine irrigation. Arch Surg 1981; 116: 716-720. QUICK CRG, VASALLODJ, COLIN JF, HEDDLE RM. Conservative treatment of major aorticgraft infection. Eur J Vasc Surg 1990; 4: 63-67. CALLIGARO KD, VErrH FJ. Diagnosis and management of infected prosthetic arotic grafts. Surgery 1991; 110: 805-813. BAHNINI A, RUOTOLO C, KOSKASF, KIEFFER E. In situ fresh allograft replacement of an infected aortic prosthetic graft: eighteen m o n t h s ' follow-up. J Vasc Surg 1991; 14: 98-102. ROBINSON JA, JOHANSENK. Aortic sepsis: is there a role for in situ graft reconstruction? J Vasc Surg 1991; 13: 677-684. VOLLMARJF, KOGEL H. Aortoenteric fistulas as a post-operative complication. J Cardiovasc Surg (Torino) 1987; 28: 479-484. REDDYDJ, SHEPARDAD, EVANSJR, WRIGHT DJ, SMITH RE, ERNST CB. Management of infected aortoiliac aneurysms. Arch Surg 1991; 126: 873-879. BUNT TJ. Synthetic vascular graft infections. II. Graft-enteric erosions and graft-enteric fistulas. Surgery 1983; 94: 1-9. JACOBSMJHM, REUL GJ, GREGORICl, COOLLYDA. In situ replacem e n t and extra-anatomic bypass for the treatment of infected abdominal aortic grafts. Eur ]Vasc Surg 1991; 5: 83-86. QUINONES-BALDRICHWJ, HERNANDEZJJ, MOORE WS. Long-term results following surgical management of aortic graft infection. Arch Surg 1991; 126: 507-511. REILLY LM, EHRENFELD WK, STONEYRJ. Delayed aortic prosthetic reconstruction after removal of an infected graft. Am J Surg 1984; 148: 234-239.
Accepted 12 October 1992
Eur J Vasc Surg Vol 7, May 1993
Management of Primary Aortic Graft Infection by Extra-anatomic Bypass Reconstruction* Thomas Lehnert, Hans-Peter Gruber, Norbert Maeder and Jens-Rainer Allenberg Department of Surgery, University of Heidelberg, Germany In this retrospective study, 21 patients requiring treatment for primary infection of an aortic prosthesis between 1981 and 1991 were identified from a prospective register. Ten of the 21 patients had had additional peripheral reconstructive vascular surgery before the diagnosis qt'aortic graft infection. The median interval between aortic graft insertion and diagnosis of graft infection was 16 months (range 1-84). Infected grafts were removed and an extra-anatomic bypass constructed in all patients. All but three patients had axillodistal reconstruction. Six patients had simultaneous operations, whilst the other 15 patients had a staged procedure with extra-anatomic reconstruction preceding graft removal. Two patients died before discharge from the hospital (9.5%). No patient required extremity amputation in the perioperative period. By life-table analysis patient survival (including perioperative deaths) was 80 % at I year, 55 % at 3 years and 40 % at 5 years. Primary graft patency was 62 % at 1 year, 51% at 3 years and 40% at 5 years. Limb salvage rate was 89% at 1 year, 63% at 3 years and 63% at 5 years. The median length of follow-up was 24 months. Extra-anatomic reconstruction in patients with aortic graft infection can be performed with low perioperative mortality. Limb salvage rates following extra-anatomic reconstruction are determined not only by the mode of reconstruction, but also by the primary disease. Key Words: Aorta; Graft replacement; Infection; Extra-anatomic bypass.
Introduction Infection of vascular prostheses represents the most troublesome postoperative complication in reconstructive vascular surgery. In patients with aortic prostheses primary graft infection is a life threatening complication. Early reports have recorded a mortality of more than 40%.1-3 A literature review of the past decade indicates that mortality of these patients still may exceed 20% (Table 1) and primary amputation rates may be as high as 31%. Several recent reports have indicated that orthotopic reconstruction, following removal of an infected aortic graft may be preferable to the standard extra-anatomic reconstruction. 11,12 Considering this new approach for our own treatment policy prompted us to review our depart-
ment's experience with the treatment of primary infected aortic prostheses.
Methods
In a retrospective study we examined 21 patients treated at the Department of Surgery, University of Heidelberg, Germany, for primary infection of aortic grafts during the 11 year period 1981-1991. Patients were identified from a prospective register of all patients undergoing arterial surgery. Patients with primary aortic infection, mycotic aneurysm, aortoenteric fistula or graft-enteric fistula were excluded from the study. Clinical data were extracted from hospital records which were available for all 21 patients. Mortality included all hospital deaths before discharge of the patient. Follow-up information was also obtained from hospital records and by contacting the patients * Presented at the 8th Annual Meeting of the German Society for and/or their local physicians. Follow-up information Vascular Surgery, Dresden, Germany, May 1992. could be obtained for all patients. Postoperative surPlease address all correspondence to: PD Dr Thomas Lehnert, Department of Surgery, University of Heidelberg, Im Neuen- vival, primary graft patency and limb salvage rates were calculated by the life-table method. 13 heimer Feld 110, D-6900 Heidelberg, Germany. 0950-821X/93/070301+07 $08.00/0© 1993Grune & Stratton Ltd.
302
T. Lehnert e t al.
Table 1. P r i m a r y aortic g r a f t i n f e c t i o n p e r i o p e r a t i v e m o r t a l i t y
Author
Reference
Number of cases
Year
Mortality (%)
Comment
Szilagyi
(1)
1972
17
7 (41%)
Bunt
(2)
1983
105
29 (28%)
review
Trout
(3)
1984
37
16 (43%)
review
Fulenwider
(4)
1983
11
0 (0%)
O'Hara
(5)
1986
51
7 (14%)
30 days
Reilly
(6)
1987
58
8 (14%)
30 days
Edwards
(7)
1988
16
3 (19%)
Yeager
(8)
1990
23
5 (22%)
Ricotta
(9)
1991
24
5 (21%)
(10)
1992
7
2 (29%)
1992
21
2 (10%)
Olah Present series
Results The m e a n age of the 21 patients (three w o m e n a n d 18 m e n ) w a s 62 (_+9) y e a r s at the time graft infection was diagnosed.
the diagnosis of graft infection w a s 16 m o n t h s (range 1-84). In s e v e n patients (33%) graft infection w a s d i a g n o s e d w i t h i n 6 m o n t h s of the p r i m a r y o p e r a t i o n a n d in three p a t i e n t s (14%) the time interval b e t w e e n the p r i m a r y o p e r a t i o n a n d diagnosis of graft infection e x c e e d e d 5 years (Fig. 1). 100
Primary aortic grafting Sixteen of the 21 patients w e r e initially treated at this d e p a r t m e n t , while five patients (24%) h a d their prim a r y o p e r a t i o n at o t h e r hospitals. P r i m a r y aortic surg e r y w a s p e r f o r m e d for aortoiliac occlusive disease in 17 patients a n d for a n infrarenal aortic a n e u r y s m in four patients. Peripheral i s c h a e m i a w a s classified according to Fontaine as stage I (n = 2), stage lib (n = 6), stage III (n = 6) a n d stage IV (n = 7). Aortodistal bifurcation grafts w e r e placed in 15 patients. Six patients h a d unilateral a o r t o f e m o r a l reconstruction w i t h p e r i p h e r a l a n a s t o m o s e s at the level of the c o m m o n (n = 4) or d e e p f e m o r a l (n = 2) artery. All unilateral reconstructions w e r e p e r f o r m e d for occlusive disease. In 19 patients the distal a n a s t o m o s i s w a s at the femoral or popliteal level (90%) a n d only two patients h a d aortic grafts w i t h the distal a n a s t o m o s e s to the iliac arteries.
Time to infection The m e d i a n time interval b e t w e e n initial s u r g e r y a n d Eur J Vasc Surg Vol 7, May 1993
/ -
20
8015
r~
60 © ..~
40
E
20
0
/ I
P) 10
E
Z 5
1
1
I
I
2
i
I
3
i
t
4
i
I
5
i
I
6
i
7
0
Years Fig. 1. Time interval between primary aortic graft replacement and diagnosis of graft infection.
Causes of graft infection Precise d e t e r m i n a t i o n of the cause of graft infection w a s difficult, if not impossible in m o s t patients. In the p r e s e n t series graft infection m a y h a v e b e e n related to p r e v i o u s vascular s u r g e r y involving the site of the distal a n a s t o m o s i s of s u b s e q u e n t aortic reconstruc-
Bypass of Infected Aortic Grafts
tion in four patients. Five patients had perioperative complications during the initial surgery and six patients had had additional vascular surgery involving the site of the distal anastomosis of the aortic graft prior to the diagnosis of infection (Table 2). Three Table 2. Possible causes of graft infection
Possible cause
Total
Vascular operations before aortic grafting
4
Perioperative complications of aortic grafting
5
Haematoma requiring evacuation
2
Bypass thrombectomy
1
Small bowel perforation
1
Inguinal lymphocele
1
303
Table 3. Microbiological studies
Total Gram-positive bacteria Staphylococcus epidermidis
7
Corynebacteria
6
Staphylococcus aureus
5
Enterococcus
4
Haemolytic streptococcus
3
Acinetobacter
1
Citrobacter
1
Peptostreptococcus spp.
1
Gram-negative bacteria Pseudomonas spp.
3
Subsequent vascular operations
6
Escherichia coli
2
Later infectious complications
3
Bacteroides
1
Ischaemic colitis
1
Proteus spp.
1
Diverticulitis/abscess formation
1
Serratia spp.
1
Inguinal lymph node abscess
1
Candida spp.
4
3
Negative
2
Missing
4
'Unexplained'
patients had later complications not directly involving the vascular graft and in three patients no clinical event was noted that could have served to explain the graft infection.
Microbiologic studies Cultures taken from the site of infection revealed the presence of Gram-positive bacteria and in the majority of these cases staphylococci were demonstrable (Table 3). In four patients candida species were found and in one this was the only organism demonstrable. Sterile cultures were obtained in two patients. It should be noted, however, that due to the retrospective nature of this analysis, bacteriological studies were not performed according to a standardised protocol and the information is almost certainly incomplete. 14
taneously, because graft infection was complicated by bleeding (n = 3) or septicaemia (n = 3) requiring immediate surgical treatment. In the other 15 patients the extra-anatomic bypass was inserted first, followed approximately 1 week later by removal of the infected graft material. The rationale for the staged procedure was to reduce operative stress, ensure adequate perfusion and possibly reduce the risk of infection of the extra-anatomic graft. All reconstructions were extra-anatomic and in all but three patients a n axillo-distal bypass was inserted. Three patients had other procedures: thoracofemoral bypass because of bilateral subclavian artery stenoses, femorofemoral crossover bypass for unilateral graft infection and lateral transosseous iliacopopliteal bypass for localised infection involving only the distal portion of the aortic graft. Whenever possible the aortic stump and the site of the infected graft were covered with omentum.
Vascular reconstruction and bypass explanation Perioperative complications and causes of death All patients had the infected graft material removed. In six patients reconstruction was performed simul-
The most serious perioperative complication of graft Eur J Vasc Surg Vol 7, May 1993
T. Lehnert et al.
304
removal was injury to the ureters which was recorded in three patients. In two patients injury was diagnosed intraoperatively and treated by suture and temporary stenting. In one patient the ureteral lesion was diagnosed only postoperatively and this injury was treated by temporary stenting alone. This patient had a very stormy time, but eventually recovered. Twelve months later, however, she presented with reinfection of the extra-anatomic graft (see below). Other complications included bleeding (n = 2), ileus (n = 1), persistent/recurrent groin infection (n = 5), retroperitoneal abscess (n = 1), small bowel perforation (n = 1) and ischaemia of the sigmoid colon (n = 1). Two patients died perioperatively. One patient had a reticulum cell sarcoma which was not diagnosed until the time of graft removal. This patient died of cachexia. The patient with colonic ischaemia had a left hemicolectomy for perforation of the sigmoid colon and eventually died of multiple organ failure.
Follow-up All patients were followed for a median interval of 24 months. Life-table analysis of primary extra-anatomic bypass patency rates is given in Fig. 2. Nine out of 17
100 80
e-
(2)
(1)
40 20 I
0
1
I
2
I
3 Years
I
4
I
5
6
Fig. 3. Life-table analysis of limb salvage rates following extraanatomic bypass reconstruction for primary aortic graft infection. Patients at risk are in parenthesis. Vertical bars indicate standard deviation.
primary aortic graft was inserted for aortoiliac occlusive disease. No patient with aneurysmal disease required amputation. Nine patients died during follow-up in addition to two perioperative deaths (eight out of 17 patients with occlusive disease and three out of four patients with aneurysmal disease). Three year survival determined by life-table analysis was 55% (Fig. 4). Causes of death were cardiopul100
80
80
8
I
(4)
~D
100
60
60 -
,fi 60
8P~ (11)
(11)
¢~ 40
40
(3)
(2)
(1)
(1)
20 I
I
]
1
2
3
q
I
I
I
4 5 6 7 Years Fig. 2. Life-table analysis of primary bypass patency following extra-anatomic reconstruction for primary aortic graft infection. Patients at risk are in parenthesis. Vertical bars indicate standard deviation.
patients with occlusive disease required subsequent bypass thrombectomy 0.5-32 months after extra-anatomic reconstruction compared to one of four patients with aneurysmal disease, 4 months postoperatively. Secondary extremity amputations were necessary in five patients 3-27 months after revascularisation (median 12 months; Fig. 3). In all these patients the Eur J Vasc Surg Vol 7, May 1993
(4)
(2)
(1)
(1)
20 I
I
t
I
I
I
I
1
2
3
4 Years
5
6
7
8
Fig. 4. Life-table analysis of postoperative survival following extraanatomic bypass reconstruction for primary aortic graft infection. Fwo postoperative deaths are included. Patients at risk are in parenthesis. Vertical bars indicate standard deviation.
monary insufficiency (n = 3), upper gastrointestinal bleeding (n = 1), unknown (n = 3) and cachexia (n = 2). One patient with occlusive disease had reinfection of the extra-anatomic bypass 12 months later. This patient died postoperatively following removal of the infected extra-anatomic graft and insertion of a new extra-anatomic bypass. The cause of death was myocardial insufficiency at a time when the infection was controlled. In terms of survival, limb salvage or pri-
Bypass of Infected Aortic Grafts
mary graft patency, no valid comparison of simultaneous versus staged operations was possible because treatment was not randomised and the numbers were small, however, no obvious differences were noted between the two groups.
Discussion
Graft infection may only become apparent several years after aortic bypass grafting. The true incidence of graft infection following prosthetic replacement of the aorta is therefore ill defined. A survey of the more recent literature comprising over 4000 patients indicates that approximately 0.3% of all aortoiliac procedures are performed for aortic graft infection. It appears that the risk of infection increases with distal placement of the peripheral anastomosis. If the distal anastomosis is placed at the femoral artery level, the incidence of infection may be four times higher than with iliac anastomosis. 1,5,1s-is Causes for graft infection are similarly difficult to establish. Experimental studies have demonstrated the ability of intestinal bacteria to translocate to intraperitoneal prosthetic material. 19 Diligent microbiological studies of macroscopically non-infected graft material removed for graft thrombosis or anastomotic aneurysm have revealed the presence of microorganisms in 79% of cases. 2° Other studies have demonstrated the presence of bacteria in thrombotic material of aortic aneurysms in up to 31% of patients 2~-24 and microorganisms were demonstrable in 47% of diseased arterial vessels in the absence of overt infection. 25 In the present series more than half of the patients had repeated operations in the same vascular region or infectious complications during previous procedures. Others have also noted that patients with aortic graft infection were more likely to have had repeated vascular surgery in the same region or required reoperation for local complications particularly in the groin during the first aortic operation. 7, 9, 26,27 Aortic graft infection is particularly dangerous if there is bleeding from the proximal anastomosis or generalised sepsis. In addition, graft occlusion may result in distal ischaemia. The reported mortality of primary aortic graft infection may exceed 40% (Table 1) with primary amputation rates of up to 43% depending on the type of reconstruction. 6 Individual reports have indicated good results of local irrigation treatment using povidone-iodine 28'29 or antibiotics.3° However, reinfection with a fatal o u t -
305
come has been described 3° and follow-up of asymptomatic patients is only limited. It is also possible that such cases with an unfavourable outcome have n o t been reported in the literature. To date it would seem that this form of treatment should be reserved for patients w h o are unfit to sustain major surgery. The standard procedure for aortic graft infection includes removal of the infected prosthesis, local debridement and extra-anatomic reconstruction. 31 Graft removal and vascular reconstruction may be performed simultaneously or as a staged procedure. Some authors prefer to remove the infected prosthesis first and then perform vascular reconstruction at a later stage. 5'26 Others prefer to perform the extraanatomic reconstruction under antibiotic cover prior to removal of the infected graft at a second operation approximately 1 week later. 1,3, 6-9, 31 Whenever possible the aortic stump and the infected area should be covered with omentum. There was no obvious difference between our staged (n = 15) and simultaneous (n = 6) procedures in terms of postoperative mortality or morbidity. One patient with simultaneous bypass excision and extra-anatomic regrafting developed reinfection of the new bypass. No graft reinfection was recorded in patients with staged procedures. Other reports confirm that insertion of an extra-anatomic bypass prior to removal of the infected aortic graft carries little risk of reinfection 3"7 and lower amputation rates and mortality have been reported after staged operations than after simultaneous procedures. 6 Although to date the superiority of staged operations has not been proven by a strictly prospective and randomised study, we would concur that, where possible, a staged procedure with revascularisation followed by removal of infected graft material is likely to yield the best results. The limb salvage rate following extra-anatomic reconstruction for aortic sepsis has been previously reported as 75% at 3 years 3s and was 63% in our series. Long-term extremity preservation, however, will be determined not only by the method of reconstruction, but also by the primary disease. In the majority of patients in our series the primary operation was performed for aortoiliac occlusive disease. Progressive arterial occlusive disease rather than poor extra-anatomic bypass function may be critical for long-term limb preservation. All five extremity amputations in this series were necessary in patients in which the primary aortic graft was placed for arterial occlusive disease. In contrast, extremities could be preserved in all patients with aneurysmal disease following extra-anatomic reconstruction. Similarly, more than half of the patients with occlusive disease required bypass thrombectomy during follow-up, as Eur J VascSurg Vol 7, May 1993
306
T. Lehnert et aL
compared to only one of four patients with aneurysmal disease. These findings support previous observations indicating a higher risk of extra-anatomic bypass thrombosis in patients with occlusive disease. 38 Recently, several reports have indicated favourable results for in situ (orthotopic) aortic reconstruction. The rationale for in situ replacement is to avoid aortic stump blow out as well as ascending thrombosis of the aorta, and possibly to improve extremity perfusion. In situ replacement of the aorta has been employed for patients with primary aortic infection, mycotic aneurysm of the aorta and aorto(graft)enteric f i s t u l a e . 11'12"32-35 A review of the literature revealed that the mortality of in situ reconstruction for aortoenteric graft infection was 56% in 66 patients studied between 1958-1981. 36 In a more recent review covering the period 1980-1989, the perioperative mortality was 37% in 82 patients. 33 Experience with in situ aortic replacement for primary infection of aortic grafts (without concomitant aortoenteric fistula) is very limited. 37 The perioperative mortality of 11 patients with suspected primary aortic graft infection w h o received an in situ aortic graft replacement was reported as only 9%. However, infection of the excised graft was only proven in one patient, who subsequently died. In the other 10 patients, neither blood cultures nor specimens from the infected area revealed any bacterial growth and these patients may have had a perigraft reaction rather than infection. The true significance of this report is even more difficult to establish since the same group has previously reported data from the same time period with significant complications during follow-up which were not referred to in the more recent report (see below). 11 The risk of aortic stump blow out is, by definition, excluded after in situ reconstruction. However, disruption of the proximal anastomosis with fatal haemorrhage has been reported in over 10% of patients with in situ replacement of infected aortic grafts. 11 This may be caused by persistent infection in the retroperitoneal space maintained by the presence of prosthetic graft material. It is possible that fatal bleeding complications from the proximal anastomosis following in situ repair of primary aortic graft infection will be more frequent than aortic stump rupture after extra-anatomic reconstruction. A multi-staged procedure has been used as an alternative approach, in which initial arterial reconstruction was achieved by extra-anatomic bypass. 4'39 At a later stage when the retroperitoneal infection has definitely healed this may be replaced by an aortic in situ graft. As a planned approach this has however Eur J Vasc Surg Vol 7, May 1993
been found to be impractical for the majority of patients. 10 The role of in situ aortic replacement in patients with primary aortic graft infection has yet to be defined particularly with regard to long-term complication rates. It would seem that to date there is not sufficient evidence to abandon extra-anatomic bypass reconstruction for patients with infected aortic grafts.
References 1 SZILAGYIDE, SMITHRF, ELLIOTTJP, VRANDECICMP. Infection in arterial reconstruction with synthetic grafts. Ann Surg 1972; 176: 321-333. 2 BUNTTJ. Synthetic vascular graft infections. I. Graft infections. Surgery 1983; 93: 733-746. 3 TROUTHH, KOZLOFFL, GIORDANOJM. Priority of revascularization in patients with graft enteric fistulas, infected arteries, or infected arterial prosthesis. Ann Surg 1984; 199: 669-683. 4 FULENWlOERJT, SMITH RB, JOHNSONRW, JOHNSONRC, SALAM AA, PERDUE GD. Reoperative abdominal arterial surgery--a ten-year experience. Surgery 1983; 93: 20-27. 5 0 ' H A R A PJ, HERTZER NR, BEVEN EG, KRAIEWSKILP. Surgical management of infected abdominal aortic grafts: a review of 25year experience. J Vasc Surg 1986; 3: 725-731. 6 REILLYLM, STONEYRJ, GOLDSTONEJ, EHRENFELDWK. Improved management of aortic graft infection: the influence of operation sequence and staging. J Vasc Surg 1987; 5: 421-431. 7 EDWARDSMJ, RICHARDSONJD,KLAMERTW.Management of aortic prosthetic infections. Am J Surg 1988; 155: 327-330. 8 YEAGERRA, MONETAGL, TAYLORLM, HARRISEJ, McCONNELL MB, PORTER JM. Improving survival and limb salvage in patients with aortic graft infection. Am J Surg 1990; 159: 466469. 9 RICOTTAJJ, FAGGIOLIGL, STELLAA, CURLGR, PEER R, UPSONJ, D'ADDATO M, ANAIN J, GUTIERREZI. Total excision and extraanatomic bypass for aortic graft infection. Am J Surg 1991; 162: 145-149. 10 OLAH A, VOGT M, LASKEA, CARRELLT, BAUERE, TURINA M. Axillo-femoral bypass and simultaneous removal of the aortofemoral vascular infection site: is the procedure safe? Eur J Vasc Surg 1992; 6: 252-254. 11 WALKERWE, COOLEYDA, DUNCANJM, HALLMANGL, OTT DA, REUL GJ. The management of aortoduodenal fistula by in situ replacement of the infected abdominal aortic graft. Ann Surg 1987; 205: 727-732. 12 CHANFY, CRAWFORDES, COSELLIJS, SAFIHJ, WILLIAMSTW. In situ prosthetic graft replacement for mycotic aneurysm of the aorta. Ann Thorac Surg 1989; 47: 193-203. 13 CUTLER SJ, EDERER F. Maximum utilization of the life table method in analyzing survival. J Chron Dis 1958; 8: 699-712. 14 BERGAMINITM, BANDYKDF, GOVOSTIOSD, VETSCHR, TOWNEJB. Identification of Staphylococcus epidermidis vascular graft infections: a comparison of culture techniques. J Vasc Surg 1989; 9: 665-670. 15 GOLDSTONEJ, MOORE WS. Infection in vascular prosthesis: clinical manifestations and surgical management. Am J Surg 1974; 128: 225-233. 16 LORENTZENJE, NIELSENON, ARENDRUPH, KIMOSEHH, BILLES, ANDERSENJ, JENSENCH, JACOBSENF, RODEROC. Vascular graft infection: an analysis of sixty-two graft infections in 2411 consecutively implanted synthetic vascular grafts. Surgery 1985; 98: 81-86. 17 EDWARDSWH, MARTIN RS, JENKINSJM, EDWARDSWH, MULHERIN JL. Primary graft infections. J Vasc Surg 1987; 6: 235-239. 18 JOHNSTONKW. Multicenter prospective study of nonruptured
Bypass of Infected Aortic Grafts
19 20 21 22
23 24
25
26 27 28
abdominal aortic aneurysm. Part II. Variables predicting morbidity and mortality. J Vasc Surg 1989; 9: 437-447. MORA EM, CARDONA MA, SIMMONS RL. Enteric bacteria and ingested inert particles translocate to intraperitoneal prosthetic materials. Arch Surg 1991; 126: 157-163. KAEBNICK HW, BANDYK DF, BERGAMINI TW, TOWNE JB. The microbiology of explanted vascular prostheses. Surgery 1987; 102: 756-762. McAuLEY CE, STEED DL, WEBSTER MW. Bacterial presence in aortic thrombus at elective aneurysm resection: is it clinically significant? Am J Surg 1984; 147: 322-324. ERNST CB, CAMPBELL HC, DAUGHERTY ME, SACHATELLO CR, GRIFFEN WO. Incidence a n d significance of intra-operative bacterial cultures during abdominal aortic aneurysmectomy. Ann Surg 1977; 185: 626-633. ILGENFRITZFM, JORDAN FT. Microbiological monitoring of aortic aneurysm wall and contents during aneurysmectomy. Arch Surg 1988; 123: 506-508. BRANDIMARTEC, SANTINI C, VENDITTIM, BArOCCHIP, SERRAP, GALLO P, D'AMATI G, RIZZO L, SPEZIALEF, FIORANI P. Clinical significance of intraoperative cultures of aneurysm walls and contents in elective abdominal aortic aneurysmectomy. Eur J Epidemiol 1989; 5: 521-525. MACBETH GA, RUBIN JR, MCINTYRE KE, GOLDSTONEJ, MALONE MA. The relevance of arterial wall microbiology to the treatment of prosthetic graft infections: graft infection vs. arterial infection. J Vasc Surg 1984; 1: 750-756. TURNIPSEEDWD, BERKOFFHA, DETMER DE, ACHER CW, BELZER FO. Arterial graft infections. Delayed vs. immediate vascular reconstruction. Arch Surg 1983; 118: 410-414. MARTIN-PAREDERO V, BUSUTTIL RW, DIXON SM, BAKER JD, MACHLEDER H, MOORE WS. Fate of aortic graft removal. Am J Surg 1983; 146: 194-197. KNIGHTCD, FARNELLMB, HOLLIER LH. Treatment of aortic graft
29 30 31 32 33 34 35 36 37 38 39
307
infection with Povidone-Iodine irrigation. Mayo Clin Proc 1983; 58: 472-475. KWAAN JHM, CONNOLLY JE. Successful management of prosthetic graft infection with continuous povidone-iodine irrigation. Arch Surg 1981; 116: 716-720. QUICK CRG, VASALLODJ, COLIN JF, HEDDLE RM. Conservative treatment of major aorticgraft infection. Eur J Vasc Surg 1990; 4: 63-67. CALLIGARO KD, VErrH FJ. Diagnosis and management of infected prosthetic arotic grafts. Surgery 1991; 110: 805-813. BAHNINI A, RUOTOLO C, KOSKASF, KIEFFER E. In situ fresh allograft replacement of an infected aortic prosthetic graft: eighteen m o n t h s ' follow-up. J Vasc Surg 1991; 14: 98-102. ROBINSON JA, JOHANSENK. Aortic sepsis: is there a role for in situ graft reconstruction? J Vasc Surg 1991; 13: 677-684. VOLLMARJF, KOGEL H. Aortoenteric fistulas as a post-operative complication. J Cardiovasc Surg (Torino) 1987; 28: 479-484. REDDYDJ, SHEPARDAD, EVANSJR, WRIGHT DJ, SMITH RE, ERNST CB. Management of infected aortoiliac aneurysms. Arch Surg 1991; 126: 873-879. BUNT TJ. Synthetic vascular graft infections. II. Graft-enteric erosions and graft-enteric fistulas. Surgery 1983; 94: 1-9. JACOBSMJHM, REUL GJ, GREGORICl, COOLLYDA. In situ replacem e n t and extra-anatomic bypass for the treatment of infected abdominal aortic grafts. Eur ]Vasc Surg 1991; 5: 83-86. QUINONES-BALDRICHWJ, HERNANDEZJJ, MOORE WS. Long-term results following surgical management of aortic graft infection. Arch Surg 1991; 126: 507-511. REILLY LM, EHRENFELD WK, STONEYRJ. Delayed aortic prosthetic reconstruction after removal of an infected graft. Am J Surg 1984; 148: 234-239.
Accepted 12 October 1992
Eur J Vasc Surg Vol 7, May 1993