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Is the iliac artery a suitable inflow conduit for iliofemoral occlusive disease: An analysis of 514 aortoiliac reconstructions
Is the iliac artery a suitable inflow conduit for iliofemoral occlusive disease: An analysis of 514 aortoiliac reconstructions R. Clement Darling H I , M_D, R o b e r t P. Leather, M D , Benjamin B. Chang, M D , W'dliam E. Lloyd, M D , and Dhiraj M. Shah, M D , Albany, N.Y. Purpose: The aorta is the conventional inflow source for reconstructions in patients with aortoiliofemoral occlusive disease. In patients with unilateral iliae or femoral disease, femoral-to-femoral bypasses have been used but with less favorable patency rates. The purpose of this study is to evaluate the performance of the unobstructed iliac artery as an inflow source for ipsilateral, contralateral, or bilateral reconstructions in iliofemoral occlusive disease. Methods: Over the past 6 years 322 reconstructions have been performed with the iliac artery as the donor vessel. Patients were evaluated for proximal hemodynamically significant lesions by augmented pullout pressures during aortography. Patients who had balloon angioplasty were excluded. Results: Results were compared with 192 patients who underwent conventional aortodistal bypass operation for occlusive disease during the same period. Both groups were similar in risk factors, age, sex, and indications for operation. For the iliae group the operative mortality rate was 1.6%, and the 30-day patency rate was 97%, similar to those in the aortic group (3.6% and 95%, respectively). Cumulative patency rates at 5 years by life-table analysis were 82% for iliac artery inflow and 77% for aortic inflow reconstructions. Conclusions: Our experience suggests that an unobstructed lilac artery is a reasonable inflow source for reconstructions in iliofemoral occlusive disease. The long-term patency rate is comparable to aortodistal bypasses and superior to other extraanatomie bypasses: (J VASC SURG 1993;17:15-22.) Although the treatment of symptomatic lower extremity ischemia resulting from aortoiliac or bilateral iliac artery occlusive disease is widely accepted to be aortofemoral bypass grafting, the optimum arterial reconstruction for unilateral iliac occlusive disease is less certain. 1'2 Anatomic procedures such as aortobifemoral or aortounifemoral bypasses and aortofemoral endarterectomies have had satisfactory patency rates, and in patients who are good risks they have had acceptable mortality and morbidity rates. 3-s However, the hemodynamic stress of cross-clamping the aorta combined with the physiologic derangement caused by transperitoneal exposure of the aorta has brought about the investigation of less extensive procedures .6,7 The purpose of this study is to evaluate the performance of the hemodynamically unobstructed From the Vasoalar Surgery Section, Albany Medical College, Albany. Presented at the Forty-sixthAnnual Meeting of the Societyof Vascular Surgery, Chicago,Ill., June 8-9, 1992. Reprint requests: Dhiraj M. Shah,MD, AlbanyMedicalCollege, A-61-VA, 47 New ScotlandAve., Albany,NY 12208. 24/6/42732 0741-5214/93/$1.00 + .10.
iliac artery as an inflow source for ipsilateral, contralateral, or bilateral reconstruction in iliofemoral occlusive disease. P A T I E N T S I N T H E STUDY AND METHODS A retrospective review was conducted of all patients undergoing lower extremity revascularization with the aorta and the iliac arteries as inflow sources at the Albany Medical Center and the Samuel S. Stratton Veterans Affairs Medical Center between January 1986 and March 1992. Patient charts were reviewed, and follow-up was obtained with use of the vascular registry, office charts, and review of the vascular laboratory reports. Operative mortality rates, early graft failure, and complications were determined for each procedure. Late graft patency was determined clinically as well as by pulse volume recordings and duplex imaging. Angiography was performed for suspected failing grafts or for patients whose symptoms worsened. All patients underwent preoperative angiograplay. Aortic and iliac augmented peak systolic pullout pressures were obtained. Balloon angioplasty was 15
16
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D a r l i n g et al.
Table I. Inflow sources
Bypass Endarterectomy
Table III. Operative indication
Common iliac
External iliac
Internal iliac
136 54
67 62
3 0
Table II. Risk factors
Diabetes Smokers Hypertension Sex (males) Age (range) (mean)
Aorta based N = 192
Iliac based N = 322
13% 60% 65% 60% 31-85 62.62
21% 55% 60% 54% 17-91 64.51
performed at the discretion of the attending surgeon and radiologist. These patients were excluded from this study group. Patients with significant aortofemoral or hemodynamically significant bilateral iliac disease had aortofemoral bypasses. 5,7,8 Those patients with an unobstructed iliac artery, without significant (less than 10 torr) pressure differential, had an iliac-based procedure. When preoperative pressure measurement was inconclusive because of significant distal disease, pressure measurement was repeated after the bypass was completed. These patients fell into one of two groups. Iliac bypass with a prosthetic material or iliofemoral endarterectomy.6,8,9 Decision for endarterectomy was based on operator's judgement depending on the anatomic and logistic suitability. All operations were performed by use of the extraperitoneal route as previously described. 1,~° Late follow-up consisted of sequential pulse volume recordings, with segmental pressures or duplex imaging or both. Late failures were defined by either graft occlusion or restenosis requiring further operative procedures. The life-table analysis was used to analyze this patient group. Chi-square analysis was used for comparison of mortality rates, and life-table analysis and comparison were performed with Wilcoxon analysis with the BMDP Software analytical package. 11 The follow-up period ranged from 1 month to 70 months, with a mean of 21 months. Twenty-three of 322 patients (7%) were lost to follow-up after 30 days. Patency was determined by objective criteria with use of vascular laboratory testing.
Indications
Aorta based N = 192
Iliac based N = 322
Claudication Tissue loss Rest pain Other
39% 21% 34% 6%
34% 26% 32% 8%
Table IV. Morbidity in surviving patients Complications
Aorta based
Iliac based
Occlusion Cardiac Respiratory Hemorrhage Other Vascular infection
10 6 2 2 0 0
10 5 0 2 3 0
RESULTS Over the past 6 years, 830 aorta-based bypasses have been performed, 192 of these opcrations were aortobifemoral grafts for occlusive disease. During the same period 322 arterial reconstructions have been performed with use of the iliac artery as the donor vessel; 180 originated from the common iliac artery, 139 from the external iliac artery, and three from the internal iliac artery. Subgroups of iliac bypass and iliac endarterectomy are listed in Table I. Risk factors, demographics, and indications for operation were similar in both groups (Tables II and III). The 30-day mortality rate for the group having aortofemoral bypass was 3.6% as compared with 1.6% for the patients with iliac-based inflow (p = 0.22). Most deaths were caused by cardiovascular complications (Table IV). All of our patients undergoing aortic surgery were admitted overnight to the intensive care unit and were intubated with full hemodynamic monitoring. Fewer than 15% of our patients undergoing iliacbased procedures required admission to the critical care unit. The 30-day primary patency rates for aortobifemoral grafts was 95% as compared with 97% for the iliac-based bypass group (p = 0.23). Ten of 322 bypasses failed and ultimately required aortobifemoral bypasses. Cumulative patency rates at i and 5 years were 91% and 77%, respectively, for the group undergoing aortobifemoral bypass, which was comparable to the latency rates found in our iliac-based reconstruction, 90% and 82%, (p = 0.76 and 0.60), respectively. The life-table analysis is represented in Tables V and VI, and tabulation of the
Volume 17 Number 1 January 1993
The iliac artery as an inflow source
17
Table V. Life-table analysis of patency Aorta-based bypasses Follow-up
A t risk
Occluded
Interval patency
< 30 days 1-6 m o 7-12 m o 13-i8 m o 19-24 m o 25-30 mo 31-36 m o 32-42 m o 43-48 m o 4%52 m o 53-60 m o
192 175 127 93 75 64 49 36 29 20 12
10 4 2 0 2 1 2 2 0 0 0
0.97 0.98 1.00 0.97 0.98 0.95 0.94 1.00 1.00 1.00
Cumulative patency 0.95 0.92 0.91 0.91 0.88 0.86 0.82
0.77 0.77 0.77 0.77
Table VI. Life-table analysis of patency Iliac artery as inflow Follow-up
A t risk
Occluded
Interval patency
Cumulative patency
< 30 days 1-6 m o 7-12 m o 13-18 m o 19-24 mo 25-30 m o 31-36 mo 37-42 m o 43-48 m o 49-52 m o 53-60 m o
322 307 255 215 176 137 105 71 52 33 20
10 8 10 4 3 0 3 0 1 0 0
0.97 0.96 0.98 0.98 1.00 0.97 1.00 0.98 1.00 1.00
0.97 0.94 0.90 0.88 0.87 0.87 0.84 0.84 0.82 0.82 0.82
two types ofiliac reconstructions is outlined in Tables VII and VIII. Ten of 322 patients required conversion of the iliae-based reconstruction to an aortic procedure. All of these were performed successfully for limb salvage without morbidity or deaths. DISCUSSION Unilateral iliac artery occlusion offers the surgeon several options for surgical reconstruction. These options include complete bypass of the aortoiliac segment or limited endarterectomy)'s'9'~2~4 Both have good results, but the mortality rate is significant (2% to 5%) even in patients who arc good risks undergoing aortic surgery. Taking this into consideration, many authors have advocated the use of extraanatomic (axillofcmoral and femorofemoral) bypasses for elderly patients or patients who are poor risks, with variable results. 7'isis Making use of the iliac artery as an inflow source is appealing for numerous reasons. In planning an optimal procedure one would strive to preserve the maximum native circulation, keep the bypasses as
short as possible, and if prostheses are used, protect them with fascia or muscle. It is also imperative, as in all vascular procedures, that the inflow to these bypasses be hemodynamicallysound and the outflow be optimal. Selected patients had augmented pullout pressures during angiography. Many patients had pressures measured after completion of the bypass and Doppler flow determination to ensure adequate inflow. The 30-day, 1-year, and 5-year cumulative patency rates of our total and subgroups are comparable to our result with aortobifemoral grafts. We have not been able to duplicate the good results of extraanatomic bypasses as demonstratedby Brief et al.,t9 Mannick and Maini, 2° and Fahal et al.21 who have 5-year patency rates of 83% to 91%. Our results with iliofemoral endarterectomy corroborate those of Inahara and Pineda. 1 We think that endarterectomy is an excellent and durable procedure and offers the advantages of an autogenous arterial repair with possibly less susceptibility to infection and false aneurysm formation. No infections occurred in either group in this series. However,
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Darling et al.
Table VII. Life-table analysis of patency Iliac endarterectomy Follow-up
A t risk
Occluded
Interval patency
Cumulative patency
< 30 days 1-6 mo 7-12 m o 13-18 m o 19-24 mo 25-30 m o 31-36 m o 32-42 m o 43-48 m o 49-52 mo 53-60 m o
116 114 93 79 64 54 41 28 19 12 8
0 2 3 2 0 0 1 0 0 0 0
0.98 0.97 0.97 1.00 1.00 0.97 1.00 1.00 1.00 1.00
100 0.98 0.95 0.92 0.92 0.92 0.89 0.89 0.89 0.89 0.89
Table VIII. Life-table analysis of patency Iliac bypass Follow-up
A t risk
Occluded
Interval patency
Cumulative patency
< 30 days 1-6 m o 7-12 m o 13-18 m o 19-24 m o 25-30 mo 31-36 mo 37-42 m o 43-48 mo 49-52 mo 53-60 m o
206 193 162 136 112 83 64 43 33 21 12
10 6 7 2 3 2 0 0 1 0 0
0.95 0.97 0.95 0.98 0.97 0.97 1.00 1.00 0.96 1.00 1.00
0.95 0.92 0.88 0.86 0.84 0.81 0.81 0.81 0.78 0.78 0.78
endarterectomy is a technically more demanding procedure that requires impeccable attention to detail, especially with regard to the termination of the endarterectomy. Our results with iliofemoral bypass with a 5-year patency rate of 82% are comparable to 77%, 4-year patency as seen by Couch et al.22, Piotrowski et al.,23 and Kalman et al.24 whose earlier study reestablished the concept of iliac-based inflow bypasses. They similarly concluded that if the patients have suitable arterial anatomy it is a viable alternative for patients who are good risks as well as those who are poor risks. The common femoral and the deep femoral arteries were used with equal frequency. The superficial femoral artery was patent in 145 (45%) of our patients in the iliofemoral group and 72 (38%) in the aortobifemoral group. However, in these subgroups no significant differences occurred in cumulative patency according to runoff. We agree with Kalman et al.24 that an aggressive approach to optimizing deep femoral outflow by extending the distal anas-
tomosis across the deep femoral orifice improved our long-term patency of these bypasses. In addition, we are not hesitant to add a distal bypass procedure if we think that the deep femoral outflow is inadequate to meet patients' clinical needs. Seven patients had a combined procedure in the aortobifemoral group, and 16 patients had distal bypasses performed during the admission in the iliac-based inflow groups. (These groups were too small for statistical analysis.) All distal bypasses were done for indication of massive tissue loss on the basis of clinical judgement. In summary, patients with a hemodynamically unobstructed iliac artery, with symptomatic iliofemoral disease, who otherwise might undergo a more extensive aortic-based procedure; or patients who are poorer risks and are offered a potentially less durable extraanatomic bypass, could benefit from an iliacbased inflow bypass. The long-term patency rate from this series is comparable to aortofemoral reconstruction and, in our experience, superior to extraanatomic procedures.
Volume 17 Number 1 January 1993
REFERENCES 1. Inahara T, Pineda JD. Extraperitoneal endarterectomy for unilateral iliofemoral occlusive disease. Surgery 1974;75: 771-5. 2. Perler BA, Burdick JF, Williams MG. Femoro-femoral or ilofemoral bypass for unilateral inflow reconstruction. Am J Surg 1991;16i:426-30. 3. Brewster DC, Darling RC. Optimal methods of aortoiliac reconstruction. Surgery 1978;84:739-48. 4. Malone JM, Moore WS, Goldstone J. The natural history of bilateral aortofemoral bypass grafts for ischemia of the lower extremities. Arch Surg 1975;110:1300-6. 5. Crawford ES, Bomberger RA, Glaeser DH, Saleh SA, Russel WL. Aortoiliac occlusive disease: factors influencing survival and function following reconstructive operation over a twenty-five-year period. Surgery 1981;90:1055-67. 6. Inahara T. Evaluation of endarterectomy for aortoiliac and aortoiliofemoral occlusive disease. Arch Surg 1975;110: 1458-64. 7. LoGerfo FW, Johnson WC, Corson JD, et al. A comparison of the late patency rates of axillobilateral femoral and axillounilateral femoral grafts. Surgery 1977;81:33-40. 8. Flanigan DP, Pratt DG, Goodreau JJ, Burnham SJ, Yao JST, Bergan Jl. Hemodynamic and angiographic guidelines in selection of patients for femorofemoral bypass. Arch Surg 1978;113:1257-62. 9. Nevelsteen A, Suy R, Daenen W, Boel A, Stalpaert G. Aortofemoralgrafting: factors influencing late results. Surgery 1988;88:642-53. 10. Helsby R, Moossa AR. Aorto-iliacreconstruction with special reference to the extraperitoneal approach. Br J Surg 1975; 62:596-600. 11. Benedetti J, Yuen K, Young L. Life tables and survivor functions. In: Dixon WJ, ed. BMDP statistical software manual. Berkeley, CA: University of California Press, 1990. 12. Duncan WC, Linton RR, Darling RC. Aortoiliofemoral atherosclerotic occlusive disease: comparative results of endarterectomy and Dacron bypass grafts. Surgery 1971;70:97484.
The iliac artery as an inflow source
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13. Inahara T. Eversion endarterectomy for aortoiliofemoral occlusive disease. A 16-year experience. Am J Surg 1979;138: 196-204. 14. Vitale GF, Inahara T. Extraperitoneal endarterectomy for iliofemoral occlusive disease. J VAsc SURG 1990;12:40815. 15. Ray LI, O'Connor JB, Davis CC, et al. Axillofemoral bypass: a critical reappraisal of its role in the management of aortoiliac occlusive disease. Am J Surg 1979;138:117-28. 16. Parsonnet V, Alpert J, Brief DK. Femorofemoral and axillofemoral grafts-compromise or preference. Surgery 1970; 67:26-33. 17. Harris JP, Flinn WR, Rudo ND, Bergan JJ, Yao JST. Assessment of donor limb hemodynamics in femorofemoral bypass for claudication. Surgery 1981;90:764-73. 18. Kalman PG, Hosang M, Johnston KW, et al. Unilateral iliac disease: the role of iliofemoral bypass. J VASCSURG 1987;6: 139-43. 19. Brief DK, Brener BJ, Alpert J, Parsonnet V. Crossover femorofemoral grafts followed up five years and more. Arch Surg 1975;110:1294-9. 20. Maunick JA, Maini BS. Femorofemoral grafting: indications and late results. Am J Surg 1978;136:190-2. 21. Fahal AH, McDonald AM, Marston A. Femorofemoral bypass in unilateral iliac artery occhlsion. Br J Surg 1989;76: 22-5. 22. Couch NP, Clowes AW, Whittemore AD, Lombara JA, Henderson BA, Mannick JA. The lilac-origin arterial graft: a useful alternative for iliac occlusive disease. Surgery 1985;97: 83-7. 23. Piotrowski J, Pearch WH, Jones DN, et al. Aortobifemoral bypass: operation of choice for tmilateral iliac occlusion? J VASCSURG 1988;8:211-8. 24. Kalman PG, Hosana M, Johnson RW, et al. Unilateral iliac disease: the role of iliofemoral bypass. J VAsc StrinG 1987;6: 139-43.
Submitted June 12, 1992; accepted Sept. 20, 1992.
DISCUSSION Dr. Bruce Brener (Millburn, N.J.). This report describes the results of endarterectomies and bypasses originating at the iliac artery. These operations have really not received enough attention in the literature. I would like to focus my remarks on a comparison between the femorofemoral and the iliofemoral and leave the discussion of aorta-based procedures and endarterectomies to the other discussants. I think there are three reasons why the iliofemoral is a better operation and three reasons why the femorofemoral is a better operation. The main advantage o f the iliofemoral operation is that the graft does not involve the asymptomatic side, and with the femorofemoral operation the donor artery is exposed to
potential injury and infection. We have inserted approximately 228 femorofemoral bypasses over the last 25 years, and we had to remove five because o f infection, but fortunately none o f the donor sides were involved, so my first question is: Was the donor artery injured or involved in any patient undergoing femorofemoral bypass in your series? The second advantage of the iliofemoral procedure is the ease with which a distal bypass can be performed, since the grafts are in line with the natural vessels. With the femorofemoral operation the graft makes a tangential approach to the femoral vessels and invites the possibility of a kink at the proximal anastomosis of the distal graft. And the third possible advantage of the iliofemoral
20
Darling e~ al.
bypass is the superior patency rate. It is interesting that there have been six recent reports on iliofemoral bypass and the patencies have ranged from 48% to 93%. The variation suggests to me that these differences are related to patient selection, but unforrtmately no prospective study has ever been carried out that compares iliofemoral and femorofemoral bypasses in patients who could undergo either operation. I think until this is done we will not know if there is an intrinsically better patency rate. My second question is: Do you think the differences in patency in your two series, the iliofemoral and the femorofemoral, were based on selection or the intrinsic superiority of the iliofemoral graft? I think the femorofemoral procedure has three advantages. The first and most obvious is that the iliofemoral bypass can not be done in a patient with a common iliac occlusion and that is probably the best indication, at least in our series, for the femorofemoral procedure. The common iliac artery, although patent, may be severely calcified, and I think that is a disadvantage of the iliofemoral operation, so my third question is: Do you evaluate the extent of the common iliac calcification before operation? Do you avoid the procedure in patients with heavily calcified arteries? And if not, do you have any special techniques for dealing with these treacherous arteries? The third advantage of the femorofemoral bypass, I think, is that it can be performed with the patient under local anesthesia, and although the authors may claim that the iliofemoral bypass has the same morbidity and mortality rate as the femorofemoral, I do not think that this claim would hold up if patients at high risk had both operations. Intuitively the iliofemoral bypass seems like a little bigger operation, certainty less than an aortofemoral bypass, where the aorta has to be cross-clamped. I have two brief final questions: Does endarterectomy or angioplasty of the distal aorta or common iliac artery adversely affect the patency of iliofemoral reconstruction? And finally, is there a difference in patency if the donor artery is the common iliac or the external iliac? Dr. R. Clement Darling I I I . Thank you very much, Dr. Brener, for your kind comments. To answer your first question, as of yet none of the 322 reconstructions have become infected or had to be removed because the artery was injured or infected. The difference in patency rates for the iliofemoral grafts as opposed to the femorofemoral grafts, I believe, is twofold. You mentioned two things. Hemodynamically the iliofemoral bypass is a much sounder operation and it is a much sounder conduit. The subcutaneous route of the femorofemoral graft, plus the exposure of both groins, which has potential for increased infection, are two negatives for the femorofemoral graft. Also, and probably more significant, is the retrograde flow that is mandated by a femorofemoral graft. Many studies have shown that there is turbulence and disruption in the flow as well as inertial losses in energy through the
Journal of VASCULAR SURGERY
femorofemoral graft or an axillofemoral graft, so the iliofemoral bypass is a sounder graft, and this may influence the patency rate. To answer the third question about calcification of the vessels, I do not know of a good preoperative method for evaluation of calcification of an artery. And I do not believe that calcification should ever be contraindication for a vascular operation. There are few ways you can gain access to a calcified vessel. One is if you manipulate it and find the break point in the calcium, that is probably a good place to either start or end an endarterectomy or bypass as well as to place a clamp. Second, an area where there is less calcification tends to be around the branch points of arteries. If you cannot place a clamp easily, you can always gain access to the artery through a branch and place an intravascular balloon to occlude the artery. However, it is imperative to ensure that the calcified artery is hemodynamically sound by investigating it during operation before and after completion of the bypass. Dr. David Brewster (Boston, Mass.). I certainly agree that in selected circumstances, unilateral iliac procedures can be a useful and appropriate reconstructive option for some patients with inflow disease. However, the question is the frequency of such utility. I was quite surprised at the preponderance of iliac-based procedures in the authors' series of aortoiliac reconstruction. Our own use of such methods has been much more limited. In our experience, aortoiliac disease is generally a bilateral process with obliterative lesions centered around the aortic bifurcation. Even in patients with symptoms largely confined to one side, we continue to think the best corrective procedure in the patient who is a good risk is an aortobifemoral graft. This provides the most definitive revascularization with essentially equivalent mortality risk, avoids potential compromise of more distally based grafts by progressive distal aortic or iliac origin disease, and obviates the possible need for later operation on the contralateral side. Do the authors have any data regarding the development of symptomatic disease on the unoperated iliac system? Second, do you think that the relatively short mean follow-up of 16 months in your series is a limitation on your conclusion that iliofemoral grafts offer long-term results equivalent to aortofemoral bypass? We have restricted use of iliofemoral grafts to those patients who are older or at higher risk and who have unilateral external iliac disease in which the common iliac artery is relatively free of disease and suitable for proximal anastomosis. This has been a relatively small subset of patients in our experience. If the common iliac artery is diseased, we have generally preferred a femorofemoral bypass. Whether ifiofemoral or femorofemoral grafts yield better long-term results is still controversial, as mentioned by Dr. Brener, with several recent studies reaching conflicting conclusions.
Volttrne 17 Number 1 January 1993
We currently rarely use iliac endarterectomy. If iliac disease is extensive, bypass has proved technically easier and has given better long-term results in our hands. If iliac disease is more focal, percutaneous transluminal angioplasty has usually provided beneficial results equivalent to more localized endarterectomy. In summary, this valuable report certainly reemphasizes the value of this particular option, that is, iliac-based procedures, in the management of aortoiliac disease. Dr. Toshio Inahara (Portland, Or.). Unilateral iliofemoral occlusive disease is a fascinating entity, if it can be called that, because it offers options for at least six methods of arterial reconstruction, five of which are bypasses and one endarterectomy. All of these various procedures are well documented, effective, and provide acceptable-to-excellent patency results. The author has alluded to all of these techniques. Because I am a proponent of endarterectomy, I will confine my comments to endarterectomy as it applies to iliofemoral occlusive disease. There are three techniques of endarterectomy that can be applied to this vessel. First is a fifll-length open endarterectomy with vein patch angioplasty. With this technique, Taylor and Porter reported a 100% 6-year cumulative patency rate. Second, the closed endarterectomy uses the Wiley or Cannon endarterectomy loops. With this technique, van den Dugen recently reported an 83% 5-year cumulative patency rate. Third, by the eversion technique, also an open endarterectomy, the entire segment from the origin of the common iliac to the common femoral bifurcation is endarterectornized. This technique has given us a 90% 5-year cumulative patency rate. These results are nearly identical to those reported by the author. It appears that endarterectomy by various techniques achieves similar 5-year patency rates. With these results wc would agree that endarterectomized iliofemoral vessels serve as stable inflow vessels. I have a few questions. Referring to Table I in the manuscript, the extent of the endarterectomy was not clear because our practice is to endarterectomize the entire segment from the aortic to the femoral bifurcation. Were bypass grafts placed from the endarterectomized iliac artery to the femoral vessels? Were there any endarterectomy failures, and if so, what if any, secondary procedures were used? Dr. Martin Harrington (New York, N.Y.). We reported a similar series but with a smaller number of patients of iliofemoral bypasses at the Eastern Vascular Society meeting last month. Although we found that iliofemoral bypass had a superior patency to femorofemoral bypass overall, when patients with no prior procedure a n d no acute ischemia were excluded, we were not able to demonstrate a statistically significant difference between femorofemoral and iliofemoral bypass. Femorofemoral bypass remains a useful procedure when one does not wish to enter the abdomen or retroperitoneum.
The iliac artery as an inflow source
21
Our patency for iliofemoral bypass was adversely affected by a number of factors in univariate analysis, including endarterectomy of the recipient or donor vessels, the site of the distal anastomosis, a prior vascular procedure on the limb, acute ischemia, or acute occluded superficial femoral artery. Did any of these factors affect your results? This is a very large series ofiliofemoral bypasses, At our institution, iliac balloon angioplasty is now a more common procedure than iliofemoral bypass. Are many iliac balloon angioplasties done at your institution, or do you favor surgery and avoid iliac balloon angioplasty? Dr. Martin Levinson (Fairfield, Conn.). Nineteen years ago I presented the Medical College of Virginia experience at the ISCVS meeting, and compared aortofemoral bifurcation grafts with unilateral aortofemoral and iliofemoral grafts. At that time, because of the influence of Dr. David Hume, we were approaching the iliofemoral bypasses through a retroperitoneal approach, and most of our unilateral bypasses were on patients who had external iliac artery occlusions. Not infrequently, what was thought to be a good donor common iliac artery by arteriography actually appeared very sclerotic and with poor pulsation once exposed through a "hockey stick" retroperitoneal incision. At times, we had to struggle to extend our exposure back to the aorta. The patency rates of our unilateral grafts were not as good as our bifurcations, and we thought this was due to a poor choice of inflow artery strongly influenced by a limiting operative incision and no preoperative hemodynamic assessment of the donor vessel. I would like to ask the authors how many times they felt compromised by trying to use the common iliac artery and not the proximal aorta, or how often they had to modify their retroperitoneal incision. In addition, we had a significant number of patients who later had contralateral leg arterial surgery. H o w often did this happen in your series? Dr. Darling. Thank you very much, Drs. Brewster, Inahara, Harrington, and Levinson, for your comments. I will try to answer them as succinctly as possible. Starting with Dr. Brewster, I agree the follow-up is relatively limited, although we have at least 20 patients whose bypasses are more than 6 years old. The longevity of these bypasses is going to have to be reevaluated, and we have to follow these patients closely. As far as progression of disease, which many people have alluded to, and the retroperitoneal approach, which I will answer at the same time, I do not think that the left retroperitoneal approach has any limitations on reaching the aorta, supraceliac, even the thoracic aorta, if you need to go that high. You can extend your incision and get as proximal as you need to on the aorta so I do not think that is going to limit you as far as your proximal inflow. One has to be very honest with oneself when one does any of these operations. The reason our endarterectomies seem to do so well is that if we are not satisfied with the end point or we do not think we can do an excellent procedure with a durable outcome, we will convert to a bypass or an
22
Journal of VASCULAR SURGERY
Darling et al.
aortofemoral bypass. We have to approach each patient individually, and the operative plan should consist of a series of faUback positions, and surgeons must be truthful with what they think is going to be the best operation for the patient. We have not found proximal progression of disease to be a factor. Only 10 of the 322 patients were converted to aortobifemoral bypasses in the series. Only approximately 6% of the patients had contralateral iliofemoral or~ aortofemoral-mostly iliofemoral-bypasses. Thus we do not believe this to be a contraindication. We believe in treating patients' symptoms and disease and not the potential for progression. Percutaneous transluminal angioplasty is used extensively in our institution. We work very well with our interventional radiologists, and if they think they can safely and effectively do a common iliac or external iliac angioplasty, whether it be one or multiple, they will perform it. However, since atherosclerosis is a systemic disease, usually disease exists in the common or external iliac arteries as well as in the groin, and instead of doing multiple angioplasties,
if we can solve it in a straightforward surgical manner, we will opt for the surgical approach. As far as Dr. Inahara's questions, we did use the common and external iliac arteries, and in three cases we used the internal iliac artery as the inflow source. We go to the best distal vessel we can find, as long as it has a hemodynamically sound inflow source. If there was not a lot of disease in the common iliac artery, we would start our endarterectomy or our bypass off the external iliac vessel. And that, again, has to be a clinical decision. So if we started the endarterectomy on the external iliac, that is what we listed it as. Some endarterectomies failed. If these patients were symptomatic, an appropriate bypass was performed. And as far as Dr. Harrington's questions, we always try to optimize the outflow. The limitations of any of these bypasses, I believe, is the outflow vessels. Again, one has to assess them clinically and through angiogram. Angioplasty has not replaced this bypass. It has just supplemented our experience with these operations and more distal procedures.
BOUND VOLUMES AVAILABLE TO SUBSCRIBERS Bound volumes of the JOURNAL OF VASCULAR SURGERY for 1993 are available to subscribers only. They may be purchased from the publisher at a cost of $69.00 for domestic, $89.83 for Canadian, and $85.00 for international subscribers for Vol. 17 (January to June) and Vol. 18 (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 Dr., St. Louis, MO 63146-3318, USA. In the United States call toll free (800)325-4177, ext. 4351. In 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.
iliac artery as an inflow source for ipsilateral, contralateral, or bilateral reconstruction in iliofemoral occlusive disease. P A T I E N T S I N T H E STUDY AND METHODS A retrospective review was conducted of all patients undergoing lower extremity revascularization with the aorta and the iliac arteries as inflow sources at the Albany Medical Center and the Samuel S. Stratton Veterans Affairs Medical Center between January 1986 and March 1992. Patient charts were reviewed, and follow-up was obtained with use of the vascular registry, office charts, and review of the vascular laboratory reports. Operative mortality rates, early graft failure, and complications were determined for each procedure. Late graft patency was determined clinically as well as by pulse volume recordings and duplex imaging. Angiography was performed for suspected failing grafts or for patients whose symptoms worsened. All patients underwent preoperative angiograplay. Aortic and iliac augmented peak systolic pullout pressures were obtained. Balloon angioplasty was 15
16
Journal of VASCULAR SURGERY
D a r l i n g et al.
Table I. Inflow sources
Bypass Endarterectomy
Table III. Operative indication
Common iliac
External iliac
Internal iliac
136 54
67 62
3 0
Table II. Risk factors
Diabetes Smokers Hypertension Sex (males) Age (range) (mean)
Aorta based N = 192
Iliac based N = 322
13% 60% 65% 60% 31-85 62.62
21% 55% 60% 54% 17-91 64.51
performed at the discretion of the attending surgeon and radiologist. These patients were excluded from this study group. Patients with significant aortofemoral or hemodynamically significant bilateral iliac disease had aortofemoral bypasses. 5,7,8 Those patients with an unobstructed iliac artery, without significant (less than 10 torr) pressure differential, had an iliac-based procedure. When preoperative pressure measurement was inconclusive because of significant distal disease, pressure measurement was repeated after the bypass was completed. These patients fell into one of two groups. Iliac bypass with a prosthetic material or iliofemoral endarterectomy.6,8,9 Decision for endarterectomy was based on operator's judgement depending on the anatomic and logistic suitability. All operations were performed by use of the extraperitoneal route as previously described. 1,~° Late follow-up consisted of sequential pulse volume recordings, with segmental pressures or duplex imaging or both. Late failures were defined by either graft occlusion or restenosis requiring further operative procedures. The life-table analysis was used to analyze this patient group. Chi-square analysis was used for comparison of mortality rates, and life-table analysis and comparison were performed with Wilcoxon analysis with the BMDP Software analytical package. 11 The follow-up period ranged from 1 month to 70 months, with a mean of 21 months. Twenty-three of 322 patients (7%) were lost to follow-up after 30 days. Patency was determined by objective criteria with use of vascular laboratory testing.
Indications
Aorta based N = 192
Iliac based N = 322
Claudication Tissue loss Rest pain Other
39% 21% 34% 6%
34% 26% 32% 8%
Table IV. Morbidity in surviving patients Complications
Aorta based
Iliac based
Occlusion Cardiac Respiratory Hemorrhage Other Vascular infection
10 6 2 2 0 0
10 5 0 2 3 0
RESULTS Over the past 6 years, 830 aorta-based bypasses have been performed, 192 of these opcrations were aortobifemoral grafts for occlusive disease. During the same period 322 arterial reconstructions have been performed with use of the iliac artery as the donor vessel; 180 originated from the common iliac artery, 139 from the external iliac artery, and three from the internal iliac artery. Subgroups of iliac bypass and iliac endarterectomy are listed in Table I. Risk factors, demographics, and indications for operation were similar in both groups (Tables II and III). The 30-day mortality rate for the group having aortofemoral bypass was 3.6% as compared with 1.6% for the patients with iliac-based inflow (p = 0.22). Most deaths were caused by cardiovascular complications (Table IV). All of our patients undergoing aortic surgery were admitted overnight to the intensive care unit and were intubated with full hemodynamic monitoring. Fewer than 15% of our patients undergoing iliacbased procedures required admission to the critical care unit. The 30-day primary patency rates for aortobifemoral grafts was 95% as compared with 97% for the iliac-based bypass group (p = 0.23). Ten of 322 bypasses failed and ultimately required aortobifemoral bypasses. Cumulative patency rates at i and 5 years were 91% and 77%, respectively, for the group undergoing aortobifemoral bypass, which was comparable to the latency rates found in our iliac-based reconstruction, 90% and 82%, (p = 0.76 and 0.60), respectively. The life-table analysis is represented in Tables V and VI, and tabulation of the
Volume 17 Number 1 January 1993
The iliac artery as an inflow source
17
Table V. Life-table analysis of patency Aorta-based bypasses Follow-up
A t risk
Occluded
Interval patency
< 30 days 1-6 m o 7-12 m o 13-i8 m o 19-24 m o 25-30 mo 31-36 m o 32-42 m o 43-48 m o 4%52 m o 53-60 m o
192 175 127 93 75 64 49 36 29 20 12
10 4 2 0 2 1 2 2 0 0 0
0.97 0.98 1.00 0.97 0.98 0.95 0.94 1.00 1.00 1.00
Cumulative patency 0.95 0.92 0.91 0.91 0.88 0.86 0.82
0.77 0.77 0.77 0.77
Table VI. Life-table analysis of patency Iliac artery as inflow Follow-up
A t risk
Occluded
Interval patency
Cumulative patency
< 30 days 1-6 m o 7-12 m o 13-18 m o 19-24 mo 25-30 m o 31-36 mo 37-42 m o 43-48 m o 49-52 m o 53-60 m o
322 307 255 215 176 137 105 71 52 33 20
10 8 10 4 3 0 3 0 1 0 0
0.97 0.96 0.98 0.98 1.00 0.97 1.00 0.98 1.00 1.00
0.97 0.94 0.90 0.88 0.87 0.87 0.84 0.84 0.82 0.82 0.82
two types ofiliac reconstructions is outlined in Tables VII and VIII. Ten of 322 patients required conversion of the iliae-based reconstruction to an aortic procedure. All of these were performed successfully for limb salvage without morbidity or deaths. DISCUSSION Unilateral iliac artery occlusion offers the surgeon several options for surgical reconstruction. These options include complete bypass of the aortoiliac segment or limited endarterectomy)'s'9'~2~4 Both have good results, but the mortality rate is significant (2% to 5%) even in patients who arc good risks undergoing aortic surgery. Taking this into consideration, many authors have advocated the use of extraanatomic (axillofcmoral and femorofemoral) bypasses for elderly patients or patients who are poor risks, with variable results. 7'isis Making use of the iliac artery as an inflow source is appealing for numerous reasons. In planning an optimal procedure one would strive to preserve the maximum native circulation, keep the bypasses as
short as possible, and if prostheses are used, protect them with fascia or muscle. It is also imperative, as in all vascular procedures, that the inflow to these bypasses be hemodynamicallysound and the outflow be optimal. Selected patients had augmented pullout pressures during angiography. Many patients had pressures measured after completion of the bypass and Doppler flow determination to ensure adequate inflow. The 30-day, 1-year, and 5-year cumulative patency rates of our total and subgroups are comparable to our result with aortobifemoral grafts. We have not been able to duplicate the good results of extraanatomic bypasses as demonstratedby Brief et al.,t9 Mannick and Maini, 2° and Fahal et al.21 who have 5-year patency rates of 83% to 91%. Our results with iliofemoral endarterectomy corroborate those of Inahara and Pineda. 1 We think that endarterectomy is an excellent and durable procedure and offers the advantages of an autogenous arterial repair with possibly less susceptibility to infection and false aneurysm formation. No infections occurred in either group in this series. However,
18
lournal of VASCULAR SURGERY
Darling et al.
Table VII. Life-table analysis of patency Iliac endarterectomy Follow-up
A t risk
Occluded
Interval patency
Cumulative patency
< 30 days 1-6 mo 7-12 m o 13-18 m o 19-24 mo 25-30 m o 31-36 m o 32-42 m o 43-48 m o 49-52 mo 53-60 m o
116 114 93 79 64 54 41 28 19 12 8
0 2 3 2 0 0 1 0 0 0 0
0.98 0.97 0.97 1.00 1.00 0.97 1.00 1.00 1.00 1.00
100 0.98 0.95 0.92 0.92 0.92 0.89 0.89 0.89 0.89 0.89
Table VIII. Life-table analysis of patency Iliac bypass Follow-up
A t risk
Occluded
Interval patency
Cumulative patency
< 30 days 1-6 m o 7-12 m o 13-18 m o 19-24 m o 25-30 mo 31-36 mo 37-42 m o 43-48 mo 49-52 mo 53-60 m o
206 193 162 136 112 83 64 43 33 21 12
10 6 7 2 3 2 0 0 1 0 0
0.95 0.97 0.95 0.98 0.97 0.97 1.00 1.00 0.96 1.00 1.00
0.95 0.92 0.88 0.86 0.84 0.81 0.81 0.81 0.78 0.78 0.78
endarterectomy is a technically more demanding procedure that requires impeccable attention to detail, especially with regard to the termination of the endarterectomy. Our results with iliofemoral bypass with a 5-year patency rate of 82% are comparable to 77%, 4-year patency as seen by Couch et al.22, Piotrowski et al.,23 and Kalman et al.24 whose earlier study reestablished the concept of iliac-based inflow bypasses. They similarly concluded that if the patients have suitable arterial anatomy it is a viable alternative for patients who are good risks as well as those who are poor risks. The common femoral and the deep femoral arteries were used with equal frequency. The superficial femoral artery was patent in 145 (45%) of our patients in the iliofemoral group and 72 (38%) in the aortobifemoral group. However, in these subgroups no significant differences occurred in cumulative patency according to runoff. We agree with Kalman et al.24 that an aggressive approach to optimizing deep femoral outflow by extending the distal anas-
tomosis across the deep femoral orifice improved our long-term patency of these bypasses. In addition, we are not hesitant to add a distal bypass procedure if we think that the deep femoral outflow is inadequate to meet patients' clinical needs. Seven patients had a combined procedure in the aortobifemoral group, and 16 patients had distal bypasses performed during the admission in the iliac-based inflow groups. (These groups were too small for statistical analysis.) All distal bypasses were done for indication of massive tissue loss on the basis of clinical judgement. In summary, patients with a hemodynamically unobstructed iliac artery, with symptomatic iliofemoral disease, who otherwise might undergo a more extensive aortic-based procedure; or patients who are poorer risks and are offered a potentially less durable extraanatomic bypass, could benefit from an iliacbased inflow bypass. The long-term patency rate from this series is comparable to aortofemoral reconstruction and, in our experience, superior to extraanatomic procedures.
Volume 17 Number 1 January 1993
REFERENCES 1. Inahara T, Pineda JD. Extraperitoneal endarterectomy for unilateral iliofemoral occlusive disease. Surgery 1974;75: 771-5. 2. Perler BA, Burdick JF, Williams MG. Femoro-femoral or ilofemoral bypass for unilateral inflow reconstruction. Am J Surg 1991;16i:426-30. 3. Brewster DC, Darling RC. Optimal methods of aortoiliac reconstruction. Surgery 1978;84:739-48. 4. Malone JM, Moore WS, Goldstone J. The natural history of bilateral aortofemoral bypass grafts for ischemia of the lower extremities. Arch Surg 1975;110:1300-6. 5. Crawford ES, Bomberger RA, Glaeser DH, Saleh SA, Russel WL. Aortoiliac occlusive disease: factors influencing survival and function following reconstructive operation over a twenty-five-year period. Surgery 1981;90:1055-67. 6. Inahara T. Evaluation of endarterectomy for aortoiliac and aortoiliofemoral occlusive disease. Arch Surg 1975;110: 1458-64. 7. LoGerfo FW, Johnson WC, Corson JD, et al. A comparison of the late patency rates of axillobilateral femoral and axillounilateral femoral grafts. Surgery 1977;81:33-40. 8. Flanigan DP, Pratt DG, Goodreau JJ, Burnham SJ, Yao JST, Bergan Jl. Hemodynamic and angiographic guidelines in selection of patients for femorofemoral bypass. Arch Surg 1978;113:1257-62. 9. Nevelsteen A, Suy R, Daenen W, Boel A, Stalpaert G. Aortofemoralgrafting: factors influencing late results. Surgery 1988;88:642-53. 10. Helsby R, Moossa AR. Aorto-iliacreconstruction with special reference to the extraperitoneal approach. Br J Surg 1975; 62:596-600. 11. Benedetti J, Yuen K, Young L. Life tables and survivor functions. In: Dixon WJ, ed. BMDP statistical software manual. Berkeley, CA: University of California Press, 1990. 12. Duncan WC, Linton RR, Darling RC. Aortoiliofemoral atherosclerotic occlusive disease: comparative results of endarterectomy and Dacron bypass grafts. Surgery 1971;70:97484.
The iliac artery as an inflow source
19
13. Inahara T. Eversion endarterectomy for aortoiliofemoral occlusive disease. A 16-year experience. Am J Surg 1979;138: 196-204. 14. Vitale GF, Inahara T. Extraperitoneal endarterectomy for iliofemoral occlusive disease. J VAsc SURG 1990;12:40815. 15. Ray LI, O'Connor JB, Davis CC, et al. Axillofemoral bypass: a critical reappraisal of its role in the management of aortoiliac occlusive disease. Am J Surg 1979;138:117-28. 16. Parsonnet V, Alpert J, Brief DK. Femorofemoral and axillofemoral grafts-compromise or preference. Surgery 1970; 67:26-33. 17. Harris JP, Flinn WR, Rudo ND, Bergan JJ, Yao JST. Assessment of donor limb hemodynamics in femorofemoral bypass for claudication. Surgery 1981;90:764-73. 18. Kalman PG, Hosang M, Johnston KW, et al. Unilateral iliac disease: the role of iliofemoral bypass. J VASCSURG 1987;6: 139-43. 19. Brief DK, Brener BJ, Alpert J, Parsonnet V. Crossover femorofemoral grafts followed up five years and more. Arch Surg 1975;110:1294-9. 20. Maunick JA, Maini BS. Femorofemoral grafting: indications and late results. Am J Surg 1978;136:190-2. 21. Fahal AH, McDonald AM, Marston A. Femorofemoral bypass in unilateral iliac artery occhlsion. Br J Surg 1989;76: 22-5. 22. Couch NP, Clowes AW, Whittemore AD, Lombara JA, Henderson BA, Mannick JA. The lilac-origin arterial graft: a useful alternative for iliac occlusive disease. Surgery 1985;97: 83-7. 23. Piotrowski J, Pearch WH, Jones DN, et al. Aortobifemoral bypass: operation of choice for tmilateral iliac occlusion? J VASCSURG 1988;8:211-8. 24. Kalman PG, Hosana M, Johnson RW, et al. Unilateral iliac disease: the role of iliofemoral bypass. J VAsc StrinG 1987;6: 139-43.
Submitted June 12, 1992; accepted Sept. 20, 1992.
DISCUSSION Dr. Bruce Brener (Millburn, N.J.). This report describes the results of endarterectomies and bypasses originating at the iliac artery. These operations have really not received enough attention in the literature. I would like to focus my remarks on a comparison between the femorofemoral and the iliofemoral and leave the discussion of aorta-based procedures and endarterectomies to the other discussants. I think there are three reasons why the iliofemoral is a better operation and three reasons why the femorofemoral is a better operation. The main advantage o f the iliofemoral operation is that the graft does not involve the asymptomatic side, and with the femorofemoral operation the donor artery is exposed to
potential injury and infection. We have inserted approximately 228 femorofemoral bypasses over the last 25 years, and we had to remove five because o f infection, but fortunately none o f the donor sides were involved, so my first question is: Was the donor artery injured or involved in any patient undergoing femorofemoral bypass in your series? The second advantage of the iliofemoral procedure is the ease with which a distal bypass can be performed, since the grafts are in line with the natural vessels. With the femorofemoral operation the graft makes a tangential approach to the femoral vessels and invites the possibility of a kink at the proximal anastomosis of the distal graft. And the third possible advantage of the iliofemoral
20
Darling e~ al.
bypass is the superior patency rate. It is interesting that there have been six recent reports on iliofemoral bypass and the patencies have ranged from 48% to 93%. The variation suggests to me that these differences are related to patient selection, but unforrtmately no prospective study has ever been carried out that compares iliofemoral and femorofemoral bypasses in patients who could undergo either operation. I think until this is done we will not know if there is an intrinsically better patency rate. My second question is: Do you think the differences in patency in your two series, the iliofemoral and the femorofemoral, were based on selection or the intrinsic superiority of the iliofemoral graft? I think the femorofemoral procedure has three advantages. The first and most obvious is that the iliofemoral bypass can not be done in a patient with a common iliac occlusion and that is probably the best indication, at least in our series, for the femorofemoral procedure. The common iliac artery, although patent, may be severely calcified, and I think that is a disadvantage of the iliofemoral operation, so my third question is: Do you evaluate the extent of the common iliac calcification before operation? Do you avoid the procedure in patients with heavily calcified arteries? And if not, do you have any special techniques for dealing with these treacherous arteries? The third advantage of the femorofemoral bypass, I think, is that it can be performed with the patient under local anesthesia, and although the authors may claim that the iliofemoral bypass has the same morbidity and mortality rate as the femorofemoral, I do not think that this claim would hold up if patients at high risk had both operations. Intuitively the iliofemoral bypass seems like a little bigger operation, certainty less than an aortofemoral bypass, where the aorta has to be cross-clamped. I have two brief final questions: Does endarterectomy or angioplasty of the distal aorta or common iliac artery adversely affect the patency of iliofemoral reconstruction? And finally, is there a difference in patency if the donor artery is the common iliac or the external iliac? Dr. R. Clement Darling I I I . Thank you very much, Dr. Brener, for your kind comments. To answer your first question, as of yet none of the 322 reconstructions have become infected or had to be removed because the artery was injured or infected. The difference in patency rates for the iliofemoral grafts as opposed to the femorofemoral grafts, I believe, is twofold. You mentioned two things. Hemodynamically the iliofemoral bypass is a much sounder operation and it is a much sounder conduit. The subcutaneous route of the femorofemoral graft, plus the exposure of both groins, which has potential for increased infection, are two negatives for the femorofemoral graft. Also, and probably more significant, is the retrograde flow that is mandated by a femorofemoral graft. Many studies have shown that there is turbulence and disruption in the flow as well as inertial losses in energy through the
Journal of VASCULAR SURGERY
femorofemoral graft or an axillofemoral graft, so the iliofemoral bypass is a sounder graft, and this may influence the patency rate. To answer the third question about calcification of the vessels, I do not know of a good preoperative method for evaluation of calcification of an artery. And I do not believe that calcification should ever be contraindication for a vascular operation. There are few ways you can gain access to a calcified vessel. One is if you manipulate it and find the break point in the calcium, that is probably a good place to either start or end an endarterectomy or bypass as well as to place a clamp. Second, an area where there is less calcification tends to be around the branch points of arteries. If you cannot place a clamp easily, you can always gain access to the artery through a branch and place an intravascular balloon to occlude the artery. However, it is imperative to ensure that the calcified artery is hemodynamically sound by investigating it during operation before and after completion of the bypass. Dr. David Brewster (Boston, Mass.). I certainly agree that in selected circumstances, unilateral iliac procedures can be a useful and appropriate reconstructive option for some patients with inflow disease. However, the question is the frequency of such utility. I was quite surprised at the preponderance of iliac-based procedures in the authors' series of aortoiliac reconstruction. Our own use of such methods has been much more limited. In our experience, aortoiliac disease is generally a bilateral process with obliterative lesions centered around the aortic bifurcation. Even in patients with symptoms largely confined to one side, we continue to think the best corrective procedure in the patient who is a good risk is an aortobifemoral graft. This provides the most definitive revascularization with essentially equivalent mortality risk, avoids potential compromise of more distally based grafts by progressive distal aortic or iliac origin disease, and obviates the possible need for later operation on the contralateral side. Do the authors have any data regarding the development of symptomatic disease on the unoperated iliac system? Second, do you think that the relatively short mean follow-up of 16 months in your series is a limitation on your conclusion that iliofemoral grafts offer long-term results equivalent to aortofemoral bypass? We have restricted use of iliofemoral grafts to those patients who are older or at higher risk and who have unilateral external iliac disease in which the common iliac artery is relatively free of disease and suitable for proximal anastomosis. This has been a relatively small subset of patients in our experience. If the common iliac artery is diseased, we have generally preferred a femorofemoral bypass. Whether ifiofemoral or femorofemoral grafts yield better long-term results is still controversial, as mentioned by Dr. Brener, with several recent studies reaching conflicting conclusions.
Volttrne 17 Number 1 January 1993
We currently rarely use iliac endarterectomy. If iliac disease is extensive, bypass has proved technically easier and has given better long-term results in our hands. If iliac disease is more focal, percutaneous transluminal angioplasty has usually provided beneficial results equivalent to more localized endarterectomy. In summary, this valuable report certainly reemphasizes the value of this particular option, that is, iliac-based procedures, in the management of aortoiliac disease. Dr. Toshio Inahara (Portland, Or.). Unilateral iliofemoral occlusive disease is a fascinating entity, if it can be called that, because it offers options for at least six methods of arterial reconstruction, five of which are bypasses and one endarterectomy. All of these various procedures are well documented, effective, and provide acceptable-to-excellent patency results. The author has alluded to all of these techniques. Because I am a proponent of endarterectomy, I will confine my comments to endarterectomy as it applies to iliofemoral occlusive disease. There are three techniques of endarterectomy that can be applied to this vessel. First is a fifll-length open endarterectomy with vein patch angioplasty. With this technique, Taylor and Porter reported a 100% 6-year cumulative patency rate. Second, the closed endarterectomy uses the Wiley or Cannon endarterectomy loops. With this technique, van den Dugen recently reported an 83% 5-year cumulative patency rate. Third, by the eversion technique, also an open endarterectomy, the entire segment from the origin of the common iliac to the common femoral bifurcation is endarterectornized. This technique has given us a 90% 5-year cumulative patency rate. These results are nearly identical to those reported by the author. It appears that endarterectomy by various techniques achieves similar 5-year patency rates. With these results wc would agree that endarterectomized iliofemoral vessels serve as stable inflow vessels. I have a few questions. Referring to Table I in the manuscript, the extent of the endarterectomy was not clear because our practice is to endarterectomize the entire segment from the aortic to the femoral bifurcation. Were bypass grafts placed from the endarterectomized iliac artery to the femoral vessels? Were there any endarterectomy failures, and if so, what if any, secondary procedures were used? Dr. Martin Harrington (New York, N.Y.). We reported a similar series but with a smaller number of patients of iliofemoral bypasses at the Eastern Vascular Society meeting last month. Although we found that iliofemoral bypass had a superior patency to femorofemoral bypass overall, when patients with no prior procedure a n d no acute ischemia were excluded, we were not able to demonstrate a statistically significant difference between femorofemoral and iliofemoral bypass. Femorofemoral bypass remains a useful procedure when one does not wish to enter the abdomen or retroperitoneum.
The iliac artery as an inflow source
21
Our patency for iliofemoral bypass was adversely affected by a number of factors in univariate analysis, including endarterectomy of the recipient or donor vessels, the site of the distal anastomosis, a prior vascular procedure on the limb, acute ischemia, or acute occluded superficial femoral artery. Did any of these factors affect your results? This is a very large series ofiliofemoral bypasses, At our institution, iliac balloon angioplasty is now a more common procedure than iliofemoral bypass. Are many iliac balloon angioplasties done at your institution, or do you favor surgery and avoid iliac balloon angioplasty? Dr. Martin Levinson (Fairfield, Conn.). Nineteen years ago I presented the Medical College of Virginia experience at the ISCVS meeting, and compared aortofemoral bifurcation grafts with unilateral aortofemoral and iliofemoral grafts. At that time, because of the influence of Dr. David Hume, we were approaching the iliofemoral bypasses through a retroperitoneal approach, and most of our unilateral bypasses were on patients who had external iliac artery occlusions. Not infrequently, what was thought to be a good donor common iliac artery by arteriography actually appeared very sclerotic and with poor pulsation once exposed through a "hockey stick" retroperitoneal incision. At times, we had to struggle to extend our exposure back to the aorta. The patency rates of our unilateral grafts were not as good as our bifurcations, and we thought this was due to a poor choice of inflow artery strongly influenced by a limiting operative incision and no preoperative hemodynamic assessment of the donor vessel. I would like to ask the authors how many times they felt compromised by trying to use the common iliac artery and not the proximal aorta, or how often they had to modify their retroperitoneal incision. In addition, we had a significant number of patients who later had contralateral leg arterial surgery. H o w often did this happen in your series? Dr. Darling. Thank you very much, Drs. Brewster, Inahara, Harrington, and Levinson, for your comments. I will try to answer them as succinctly as possible. Starting with Dr. Brewster, I agree the follow-up is relatively limited, although we have at least 20 patients whose bypasses are more than 6 years old. The longevity of these bypasses is going to have to be reevaluated, and we have to follow these patients closely. As far as progression of disease, which many people have alluded to, and the retroperitoneal approach, which I will answer at the same time, I do not think that the left retroperitoneal approach has any limitations on reaching the aorta, supraceliac, even the thoracic aorta, if you need to go that high. You can extend your incision and get as proximal as you need to on the aorta so I do not think that is going to limit you as far as your proximal inflow. One has to be very honest with oneself when one does any of these operations. The reason our endarterectomies seem to do so well is that if we are not satisfied with the end point or we do not think we can do an excellent procedure with a durable outcome, we will convert to a bypass or an
22
Journal of VASCULAR SURGERY
Darling et al.
aortofemoral bypass. We have to approach each patient individually, and the operative plan should consist of a series of faUback positions, and surgeons must be truthful with what they think is going to be the best operation for the patient. We have not found proximal progression of disease to be a factor. Only 10 of the 322 patients were converted to aortobifemoral bypasses in the series. Only approximately 6% of the patients had contralateral iliofemoral or~ aortofemoral-mostly iliofemoral-bypasses. Thus we do not believe this to be a contraindication. We believe in treating patients' symptoms and disease and not the potential for progression. Percutaneous transluminal angioplasty is used extensively in our institution. We work very well with our interventional radiologists, and if they think they can safely and effectively do a common iliac or external iliac angioplasty, whether it be one or multiple, they will perform it. However, since atherosclerosis is a systemic disease, usually disease exists in the common or external iliac arteries as well as in the groin, and instead of doing multiple angioplasties,
if we can solve it in a straightforward surgical manner, we will opt for the surgical approach. As far as Dr. Inahara's questions, we did use the common and external iliac arteries, and in three cases we used the internal iliac artery as the inflow source. We go to the best distal vessel we can find, as long as it has a hemodynamically sound inflow source. If there was not a lot of disease in the common iliac artery, we would start our endarterectomy or our bypass off the external iliac vessel. And that, again, has to be a clinical decision. So if we started the endarterectomy on the external iliac, that is what we listed it as. Some endarterectomies failed. If these patients were symptomatic, an appropriate bypass was performed. And as far as Dr. Harrington's questions, we always try to optimize the outflow. The limitations of any of these bypasses, I believe, is the outflow vessels. Again, one has to assess them clinically and through angiogram. Angioplasty has not replaced this bypass. It has just supplemented our experience with these operations and more distal procedures.
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