Isolated popliteal segment v tibial bypass. Comparison of hemodynamic and clinical results

Importance Of The Arteriographic Anatomy Of The Descending Genicular Artery And Sural Arteries In Patients With Atherosclerotic Occlusion Of The Popliteal Artery

Bypasses to the descending genicular artery (DGA) or the medial sural artery (MSA) have been performed with acceptable rates of midterm success. The arteriographic appearance of the DGA, the MSA, and the lateral sural artery (LSA) was described and the applicability of bypass to these vessels was investigated. The arteriograms of 45 patients who had occlusion of the below-knee popliteal artery were analyzed to determine the presence, dominance, and extension of collaterals for each perigeniculate branch, which were used to assess the applicability of a perigeniculate bypass. A dominant perigeniculate artery was found in 26 arteriograms and corresponded to 13 DGAs, 9 MSAs, and 4 LSAs. Of 14 applicable perigeniculate bypasses, 2 would be an obligatory bypass and 12 would be an alternative to a conventional infrapopliteal bypass. Although rarely an obligatory solution, a bypass to a perigeniculate branch artery represents a valuable alternative.

Bypass to the genicular arteries for revascularisation of the lower limb

OBJECTIVE

To describe an initial experience with infrainguinal bypass grafts inserted distally in a genicular artery.

DESIGN

Retrospective case series study.

SUBJECTS AND METHODS

Eleven patients with Grade III chronic limb ischaemia in whom arteriography showed femoropopliteal occlusive disease and at least one genicular branch suitable for receiving a bypass. Bypass grafts were done to the descending genicular artery (n=4) or the medial sural artery (n=6) using segments of autologous veins; one bypass was not completed.

RESULTS

Primary graft patency and foot salvage rates were 73% at 1 month and 24 months of follow-up. Patient survival rate was 100% and 90%, respectively. Major amputation was required in two of three patients following early graft failure. Of the eight patients who had a patent graft, the Doppler ankle-brachial systolic pressure index showed no change in one patient, an increase of 0.13-0.66 in six patients, and was not measured in one patient. The former patient underwent a below-knee amputation whereas the other seven patients showed complete healing of their skin ulcers and sites of minor amputation.

CONCLUSION

The genicular bypass is a useful alternative that may extend the limits of infrainguinal arterial reconstruction with autologous tissue and the potential for long-term patient benefit.

MR angiography in the evaluation of atherosclerotic peripheral vascular disease

Magnetic resonance (MR) angiography of lower extremity occlusive vascular disease has evolved into a feasible diagnostic imaging option. The previous emphasis on time-of-flight techniques was associated with lengthy acquisition times and artifactual signal losses. Those limitations presented an obstacle to widespread clinical implementation. However, the emergence of rapid imaging sequences combined with gadolinium chelate enhancement offers time-efficient alternatives that can yield a truer representation of the vascular anatomic structure. The technology is now poised to serve as a routine screening study, provided that radiologists understand all factors needed to generate clinically relevant MR angiograms. This article is intended to provide a useful resource directed toward achieving that understanding.

Arterial reconstruction of vessels in the foot and ankle

OBJECTIVE

This study demonstrated that arterial reconstruction of vessels of the foot and ankle can preserve the majority of ischemic extremities with extensive tibial and peroneal occlusive disease and patent pedal arteries.

SUMMARY BACKGROUND DATA

There are successful reports of bypass procedures to the ankle and foot, but despite this, these procedures have not gained widespread acceptance among surgeons performing infra-inguinal revascularization. Primary amputation is often offered for such patients. For this reason, the authors have reviewed their experience with bypasses to the foot and ankle.

METHODS

A retrospective review was done of 75 arterial bypasses (5 bilateral), done since 1985, to the ankle and foot in 70 patients (38 males and 32 females). Fifty-four (77%) of the patients were diabetic. The age ranged from 55 to 95 years. Twenty-six (37%) were older than 80 years. The patients were selected for operative intervention because of severe tibioperoneal occlusive disease with ischemic rest pain or gangrene of the foot. Digital subtraction arteriography facilitated visualization of distal vessels. Operative principles included regional anesthesia, autogenous graft material, short bypass, non-traumatic vessel occlusion, selective operative arteriography, tension free ankle and foot skin closure, and concomitant conservative debridement of infected devitalized tissue. Incomplete pedal arch did not influence decision for operation. Indications for operation were: gangrene, 42 (56%); non-healing ulcer, 21 (28%); and rest pain, 12 (16%). Graft material was in situ greater saphenous vein, 40 (53%); translocated greater saphenous vein, 19 (25%); reversed greater saphenous vein, 11 (15%); and arm vein, lesser saphenous vein or vein patch, 5 (7%). Donor artery was popliteal, 30 (41%); common femoral, 26 (35%); and superficial femoral, 17 (23%). Recipient vessel was dorsalis pedis, 43 (57%); posterior tibial, 18 (24%); distal anterior tibial, 9 (12%); and distal peroneal, plantar or tibial endarterectomy, 5 (7%).

RESULTS

There were four (5.7%) deaths and three (4.2%) graft failures within 30 days. Early graft failure led to transmetatarsal amputation (1), below knee amputation (1), and conversion of graft to femoral (1), popliteal bypass graft with limb salvage (1). In one patient, significant tissue necrosis with infection necessitated a below knee amputation within 30 days, despite a patent graft. Long-term follow-up revealed 10 graft failures, 4 major amputations, 3 graft revisions, and 15 deaths. Cumulative primary and secondary patency was 79.0% and 81.6% at 36 months. Limb salvage was 87.5% at 36 months.

CONCLUSIONS

These results support an aggressive approach to limb salvage in patients with threatened limb loss, unreconstructable tibio-peroneal occlusive disease, and patent pedal arteries. Bypasses to the ankle and foot will maintain a functional extremity in the majority of these patients.

Can intraoperative prebypass arteriography substitute for the preoperative arteriogram?

Preoperative contrast arteriography is presently considered a requirement when planning infrainguinal arterial reconstructions in patients with limb-threatening ischemia. We reviewed the clinical data from 22 infrainguinal bypasses done in 20 patients to see if appropriate decisions concerning operability and the nature of the operation could be made from the physical examination and noninvasive data supplemented by a limited intraoperative on-table prebypass arteriogram. The presence of a normal femoral pulse with either a normal thigh pulse volume tracing or a normal high-thigh index assured adequate inflow to the groin level. The presence of an arterial Doppler signal at the ankle level, heard with a hand held Doppler, confirmed the presence of patent outflow vessels for the distal anastomosis. The exact site of the distal anastomosis could be determined with the on-table prebypass arteriogram. In patients with limb-threatening ischemia due to occlusive disease limited to the infrainguinal arterial tree, an appropriate operative bypass may be performed without the aid of the preoperative arteriogram.

Preferential use of EPTFE for above-knee femoropopliteal bypass grafts

We have used polytetrafluoroethylene preferentially for bypasses to the above-knee popliteal artery since 1979. Since this approach has recently been challenged, we reviewed our experience with 138 grafts in 128 patients. The majority (74%) of patients were male with a mean age of 63.2 years. Risk factors included: smoking (85%), hypertension (55%), diabetes mellitus (45%), and coronary artery disease (41%). The indications for operation were disabling claudication (18%), rest pain (42%), gangrene/tissue loss (33%), and miscellaneous (7%). Perioperative (30 day) mortality was 3% and morbidity (excluding amputation or graft failure) was 5%. Patients were followed for up to eight years with a mean follow-up of 22.1 months. Grafts which remained patent, but did not prevent major amputation, were classified as "failed". Primary patency was 75% at one year and 54% at five years. Limb salvage was 88% at one year and 70% at five years. Risk factors, indication for operation and arteriographic runoff had no statistically significant impact on short- or long-term patency. However, bypass grafts to isolated popliteal segments had a significantly (p = 0.025) increased perioperative failure rate compared to all other grafts. Our data support the continued use of polytetrafluoroethylene for above-knee femoropopliteal bypass except perhaps in patients who require grafting to an isolated popliteal segment where higher early failure rates were seen.

Late failure of reversed vein bypass grafts

Late failure of reversed vein bypass grafts is preceded by the appearance of stenotic lesions, which progress to total occlusion. These lesions appear either as intrinsic graft lesions or as new arteriosclerotic lesions in contiguous arteries. The present study summarizes the University of Pennsylvania experience with these lesions in 521 vein grafts inserted from 1979 to 1985. The grafts were grouped according to the site of the distal anastomosis; 231 above-knee popliteal (FP AK), 171 below-knee popliteal (FP BK), and 119 tibial (FT). The overall incidence of stenotic lesions was essentially identical with the three grafts (21%), but the relative incidence of intrinsic graft to arterial lesions was higher with the more distal grafts. The most common graft lesions developed adjacent to the proximal anastomosis, which is the narrowest part of a reversed vein graft. The popliteal artery was the most common site of outflow stenosis. There was negligible incidence of tibial lesions. The most common inflow arterial lesion was located in the common femoral and iliac arteries. The superficial femoral artery (SFA) was a rare site of inflow stenosis, even though it was at risk because 96 grafts originated from the SFA or popliteal artery. Sixty-seven per cent of the graft and 52% of the arterial lesions were treated successfully by percutaneous transluminal angioplasty; the rest had minor surgical revisions. This resulted in a 19%, 10%, and 9% improvement in 5-year patency for the FT, FP BK, and FP AK bypasses. These results justify an aggressive policy of graft surveillance to identify and treat stenotic graft lesions before graft occlusion.

Maximizing the use of autogenous vein using the in situ (valve incision) technique

Bypass grafting to vessels beyond the popliteal bifurcation is an established method for treating severe limb ischaemia. Failure rate is high, however, especially when prosthetic vascular substitutes have to be used. When left in situ, saphenous vein can be used down to much smaller diameters than would be possible with reversed vein. With this method, vein utilization of around 90% can be achieved with respective increases in patency and limb salvage. Our early results with 26 in situ grafts are presented. In two cases the presence of a suitable tributary of the saphenous vein allowed a 'bifurcated' or 'femorotibial' graft to be performed. All patients (17 males, nine females) were admitted with limb threatening ischaemia. Mean ankle pressure index was 0.29 (s.d. = 0.09), range 0.18-0.53. Average graft intra-operative flow rate measured 96 ml/min. Twenty grafts remain patent while six grafts have failed. In three of these failures, performed early in the series, the graft could not be made to function at the time of surgery. The mean postoperative ankle pressure index was 0.87 (s.d. = 0.19). Cumulative patency rate at 24 months is 74%. This rises to 83% if the three 'on table' failures are excluded. Five amputations were required; four as a result of graft failure and one despite a functioning graft. Four grafts clotted within 24 h but have remained patent following immediate thrombectomy. One patient required ligation of an arteriovenous fistula on the third postoperative day.

Nonreversed and in situ vein grafts. Clinical and experimental observations

The in situ saphenous vein (ISSV) graft has shown promise in distal bypass. Although improved patency has been attributed to preservation of vasa vasorum, there is no direct evidence to support this hypothesis. Femorodistal bypass was done in 33 patients using ISSV grafts (21) or nonreversed saphenous vein (NRSV) grafts (12) during an 18-month period. The NRSV were completely removed from the vein bed but were otherwise prepared in an identical fashion to the ISSV. Immediate complications including incomplete valvulotomy (one), intimal laceration (one), persistent AV communication (two), and extrinsic graft compression (one) were identified and corrected. Two grafts of 2.5 mm diameter occluded acutely. There were no deaths. Of 30 patients discharged with a patent graft, there was one late occlusion (ISSV) at 10 months. No difference in patency between ISSV and NRSV grafts was noted during follow-up extending to 24 months. Overall limb salvage was 94%. In a canine model, 60 vein segments were interposed in the carotid artery using in situ, reversed, and nonreversed techniques. Ultrastructural studies 1, 2, 3, and 6 months after implantation reveal no differences in in situ and nonreversed grafts. New vasa vasorum were identified in NRSV within 1 month. Both ISSV and NRSV grafts demonstrate excellent patency and maintenance of smooth muscle cell architecture. Factors including reduced size disparity at the proximal and distal anastomoses, physiologic distension under arterial pressure, careful handling, and meticulous technique appear to be more important than the theoretic advantages of preserving vasa vasorum.