Remote distal arteriovenous fistula to improve infrapopliteal bypass patency

The results of the use of prosthetic materials for femorocrural bypass surgery have been less than optimal. The creation of a distal anastomotic arteriovenous fistula to augment blood flow and velocity through the graft is well known. However, it may create turbulence at the anastomosis and steal blood flow away from the distal artery. A canine model was developed to evaluate the effect of fistula size on graft/arterial hemodynamics. In 16 patients we have constructed a distal arteriovenous fistula, which is remote from the distal anastomosis, and we studied the effect of such fistulas on bypass patency and distal arterial hemodynamics. Patients selected for this procedure had multiple previously failed reconstructions and limb-threatening ischemia and did not have usable autogenous vein. Femorotibial bypass graft reconstructions were performed with polytetrafluoroethylene followed by the creation of a side-to-side arteriovenous fistula 5 to 15 cm below the distal anastomosis in the same artery and accompanying veins. We have achieved a 1-year patency of 67% with a 75% limb salvage rate. We also serially measured blood flow and velocity within the bypass, the arteriovenous fistula, and the distal outflow vessel using duplex scanning after surgery. Mean estimated blood flow through the bypass during the immediate postoperative period was 264 ml/min, the arteriovenous fistula was 157 ml/min, and the distal artery was 19 ml/min. Unlike an arteriovenous fistula created at the distal anastomosis, a remote distal arteriovenous fistula not only increases graft blood flow but also augments native arterial blood flow between the distal anastomosis and fistula and thus may improve distal limb perfusion.     

Adjunctive techniques to improve patency of distal prosthetic bypass grafts: polytetrafluoroethylene with remote arteriovenous fistulae versus vein cuffs

PURPOSE: The long-term patency for infrapopliteal bypass grafting with prosthetic material is less than optimal. Our experience demonstrates a 40% patency at 2 years for these grafts. Several adjuvant techniques have been developed to improve patency rates, two of which are a remote distal arteriovenous fistula and the creation of a distal vein cuff. This study summarizes our experience with these two techniques. METHODS: Between 1987 and 1998, 107 bypass graftings were performed to the below-knee popliteal or tibial vessels with the use of polytetrafluoroethylene. One group (48 bypass grafts) had polytetrafluoroethylene with adjuvant distal arteriovenous fistula (DAVF), and a second group (59 bypass grafts) was reconstructed with a distal vein cuff (DVC). The type of bypass grafting that was performed was based on surgeon experience and preference. Indications and demographics were similar in the two groups. All patients underwent the operation for limb-threatening ischemia, including gangrene (DAVF, 23%; DVC, 9%), ulceration (DAVF, 27%; DVC, 51%), and rest pain (DAVF, 50%; DVC, 40%). RESULTS: The primary patency rate was 48% and 38% at 3 years for DAVF and DVC, respectively. Secondary patency was 48% and 47% at 3 years, with limb salvage rates of 76% and 92% for DAVF and DVC, respectively (P <.05). Attempted thrombectomy without continuation of patency was undertaken in two patients with a failed DAVF. Attempts at restoration after thrombosis were made in eight patients with failed DVCs. Five patients underwent thrombectomy, of which four procedures were successful. Three patients had thrombolytic therapy, and two of these remained patent. CONCLUSION: Adjuvant techniques, including DAVF and DVC, produce acceptable long-term patency and limb salvage rates in bypass grafts performed to the below-knee popliteal and tibial vessels. This study suggests that DVCs may offer improved limb salvage rates and a greater opportunity for revision when bypass graft failure occurs.     

Failure of arteriovenous fistulas at distal tibial bypass anastomotic sites

Arteriovenous fistula formation has been advocated to increase the outflow for tibial and peroneal distal bypass grafts. Between January, 1981 and September, 1981, twenty-seven patients underwent thirty femoral to distal tibial or peroneal artery bypass procedures with creation of an arteriovenous fistula at the site of the distal anastomosis. Limb salvage was the primary indication for surgery in 97% of this severely ischemic group, with a mean ankle pressure index of 0.32. Despite high flow rates averaging 260 cc/minute and an initial patency rate of 97%, there were only two fistulas patent in intact limbs at the conclusion of the initial eight month follow-up period with one additional occlusion at 16 months. Limb salvage to the present (July 1983) was achieved in only six cases. In the patients with limb salvage, three bypass grafts remain patent despite fistula occlusion, two patients have occlusion of both graft and fistula but no rest pain, and a single patient has maintained both graft and fistula patency for 23 months. Creation of an arteriovenous fistula at the distal anastomotic site of tibial bypass procedures augments graft flow in the immediate post-op period; but, has very low long term patency rates and is not beneficial to graft patency or effectiveness.     

Long-term results of thrombectomy for late occlusions of aortofemoral bypass

Sixty-two first episodes of aortofemoral (eight patients) or aortobifemoral (42 patients) bypass thrombosis were operated upon in 50 patients between 1980 and 1985. There were 47 men and three women whose mean age was 58 years. Retrograde thrombectomy through the distal anastomosis was achieved in all cases by using either a balloon catheter or Vollmar rings. If thrombectomy was impossible, revascularization was ensured by an extraanatomic bypass or complete replacement of the graft. Angioplasty, repeat distal anastomosis or femoropopliteal bypass of the native runoff artery were done in 55 (89%) operations. The cause of thrombosis was elucidated in 45 cases. Suture line stenosis and atheromatous stenosis of the native runoff artery were the two most common causes. Three patients died and two required above-knee amputation in the immediate postoperative period. Contralateral embolism occurred in two patients undergoing retrograde thrombectomy. Mean follow-up was 47 months. Thrombectomy was possible in 51 of 62 prosthetic thromboses (Group I). Thirty-nine of these grafts have remained patent. Twelve instances of repeat thrombosis occurred, requiring either repeat thrombectomy or a new bypass. Primary patency in group I was 97.8%, 81.2%, and 71.3% at one, three, and five years, respectively. Thrombectomy was impossible in 11 graft thromboses (Group II). A new bypass was performed in all 11 cases. Primary patency in Group II was 100%, 75% and 50% at one, three, and five years, respectively. Retrograde thrombectomy combined with treatment of native runoff artery anomalies can restore long-term patency when thrombosis occurs late after aortofemoral bypass and is associated with low mortality and morbidity.Presented at the Annual Meeting of the Société de Chirurgie Vasculaire de Langue Française, May 18–19, 1990, Nancy, France.     

Temporary arteriovenous fistula for venous reconstruction using synthetic graft: a clinical and experimental investigation

This report discusses venous reconstructive surgery combined with a temporary distal arteriovenous fistula creation for ilio-femoral vein obstruction. One patient who had long standing, high degree edema of the left lower extremity due to postphlebitic syndrome and four patients who had acute occlusion of the iliac vein were treated by means of extra-anatomical femoro-femoral vein bypass grafting combined with temporary distal femoro-saphenous arteriovenous (a-v) fistula creation. An expanded polytetrafluoroethylene (EPTFE) graft was selected for this procedure instead of a cross-over saphenous vein. The surgically created a-v fistula was effective in keeping the implanted grafts patent for a long time in three out of the five patients. In animal experiments, the bilateral iliac veins of mongrel dogs were replaced with several kinds of synthetic graft. Femoro-femoral a-v fistulae were made only on the left side. In 26 animals, 84.6% of the synthetic grafts on the a-v fistula side were patent, whereas only 11.5% of the grafts on the control side were patent. This investigation clearly demonstrates that the increased blood flow velocity through the created distal a-v fistula preserved the patency of synthetic vein grafts.     

Revascularization of the leg using polytetrafluoroethylene: Cumulative patency in patients with claudication and limb salvage

Of 196 polytetrafluoroethylene bypass grafts in the leg, 113 were placed in the femoropopliteal and 83 in the femorotibial or femoroperoneal position. Claudication was the indication for 31 percent of the grafts, and 67 percent were done for limb salvage. Cumulative patency rates calculated by the life-table method for the femoropopliteal grafts were 66 percent at 1 year, 53 percent at 2 years, and 49 percent at 3 years. Corresponding patency rates for the femorotibial or peroneal grafts were 48, 44, and 36 percent, respectively. An analysis of factors influencing graft patency indicated that the best results were obtained with femoropopliteal grafts done for claudication in the presence of good distal runoff and grafts placed in limbs without previously failed grafts. Graft occlusion was most likely in distal bypasses for limb salvage and limbs with previously failed grafts. It is concluded that alternatives to PTFE bypass should be considered in those patients at greatest risk for graft occlusion. In patients who lack a satisfactory saphenous vein but who must have a bypass graft, polytetrafluoroethylene is an acceptable arterial substitute; however, thrombectomy or revision will be required to maintain patency in a high proportion of cases.     

Descending thoracic aorta as an inflow source for late occlusive failures following aortoiliac reconstruction

From November 1984 to March 1990, 10 descending thoracic aorta-to-femoral artery bypass procedures were performed after failure of one or several aortoiliofemoral reconstructions. All patients were men, mean age 60 years. Indications included noninfected false aneurysm of an infrarenal end-to-side aortoprosthetic anastomosis in one case; one occlusion of an axillofemoral bypass; degradation of an aortobifemoral prosthetic graft; two occlusions of aortofemoral bypass; and five occlusions of aortobiiliac or aortobifemoral bypasses. Eight bifurcated grafts, one aortoprosthetic tube graft, and one aortopopliteal tube graft were inserted. One patient died 23 days postoperatively of multiple organ failure. Three patients underwent a successful secondary lower limb reconstruction procedure (prosthetic limb thrombectomy, embolectomy, femoral bifurcation angioplasty in one case each). Mean survival time was 14 months (range 3–48 months). Two patients were lost to follow-up, and one died of myocardial infarction six months postoperatively with a patent bypass. Graft thrombosis occurred in two patients. One was treated by thrombectomy at five months, the other was treated by in-situ thrombolysis at 15 months. Both of these patients had patent grafts at 12 and 21 months, respectively. The four other patients had patent grafts at 48 months. Primary patency was 55.5% (5/9 survivors) and secondary patency was 100% (9/9). This is a relatively simple method for constructing an extraanatomic aortofemoral or aortobifemoral bypass in late failures of aortoiliofemoral reconstructive surgery without having to re-enter the abdomen.Presented at the Annual Meeting of the Société de Chirurgie Vasculaire de Langue Française, May 18–19, 1990, Nancy, France.     

Closure of a surgically created arteriovenous fistula with a covered stent-graft in a patient with venous ambulatory hypertension--a case report

The purpose of this paper is to report the use of a covered stent-graft in the endovascular treatment of a surgically created arteriovenous fistula. A 37-year-old woman with symptomatic venous ambulatory hypertension underwent a left common femoral vein-to-right common iliac vein bypass using 10 mm ringed polytetrafluoroethylene (PTFE) with creation of an arteriovenous (AV) fistula from the superficial femoral artery to the PTFE graft. At 1 year postoperatively, recurrent symptoms thought to be due to the arteriovenous fistula were treated by placement of an 8 mm x 10 cm Viabahn covered stent-graft. Placement was via crossover technique from the right common femoral artery using a 9 French sheath. At 2 months' follow-up symptoms had resolved, the AV fistula was occluded, and venous bypass remained patent. Focal arteriovenous fistulas of the proximal superficial femoral artery can be treated safely with a covered stent-graft via an endovascular approach.     

Inferior vena cava bypass: experimental evaluation of externally supported grafts and initial clinical application

Inferior vena caval obstruction is an unusual but important clinical problem for which adequate treatment previously has not been available. Recently, a polytetrafluoroethylene (PTFE) graft with external rigid spiral supports was developed that appeared particularly applicable to the venous system. In 18 dogs a 15 cm length of Impraflex was placed from the proximal right common iliac vein to the inferior vena cava (IVC) at the level of the renal veins after IVC and right iliac vein interruption. End-to-end and end-to-side iliac vein anastomoses were alternated, with and without distal femoral arteriovenous (AV) fistulas (AVFs). At 2 months, with a distal AV fistula, 11 of 12 (92%) grafts were patent, angiograms demonstrated no evidence of intraluminal clot, and there was no hind limb edema. Following AVF ligation 2 months after graft insertion, 10 grafts remained patent, but five developed some intraluminal thrombus and one of them progressed to complete occlusion. Four months after fistula ligation (6 months after graft insertion) 9 of 12 grafts (75%) remained patent. All six grafts without distal AVF were occluded within 1 week. This procedure was performed on one severely symptomatic patient who had IVC occlusion, and currently the patient shows marked improvement. Thus IVC bypass is possible when an externally supported PTFE prosthesis is complemented by a temporary AVF.     

Haemodynamics of the adjunctive arteriovenous fistula in femorodistal bypass grafting: an experimental study

The results of femorotibial bypass for limb salvage vary a great deal. One of the reasons for this might be the discrepancy between potential inflow and run-off into the foot. An arteriovenous fistula at the distal graft anastomosis may improve results but the best anatomical arrangement for the fistula is unknown. Ileofemoral grafts were performed in dogs after the hind limb was rendered ischaemic. The distal end of the graft was anastomosed proximal to, superimposed upon, or distal to an arteriovenous fistula between the femoral artery and its accompanying femoral vein. The effect of the fistula on graft/run-off haemodynamics was then measured. The adjunctive arteriovenous fistula increased inflow by a mean of 900 per cent and reduced systemic pressure by 10 per cent. Peripheral resistance was reduced by 85 per cent. Distal arterial run-off was maximized with respect to total graft flow when the graft was placed distal to the fistula (P less than 0.05). The venous steal of flow and perfusion pressure produced by the fistula was minimized with the same configuration compared to the two other arrangements (P less than 0.01 and P less than 0.05). Placement of the graft distal to the adjunctive arteriovenous fistula maximized distal arterial flow and pressure, and significantly increased graft flow.     

Patency and limb salvage after distal prosthetic bypass associated with vein cuff and arteriovenous fistula.

OBJECTIVE: To assess the usefulness of vein cuff with or without arteriovenous fistula interposition as adjuvant techniques for improving patency and limb salvage in patients undergoing femorodistal bypass surgery using prosthetic grafts. METHOD: We undertook a retrospective study of 65 consecutive patients treated over a 5-year period with 67 prosthetic femorodistal bypasses with vein cuff, in whom an arteriovenous fistula was constructed at the distal anastomosis in 35. Patients were followed for a median time period of 23 months. RESULTS: Primary patency rates were 68, 53 and 44% at 1, 2 and 3 years, respectively. The corresponding figures for secondary patency, limb survival and patients' survival were 73, 64 and 58% for 1 year, 78, 76 and 73% for 2 years and 72, 66 and 63% for 3 years. None of the criteria analyzed influenced patency or limb salvage on prosthetic bypasses using adjuvant techniques. No statistical differences were found between patency and limb salvage rates in patients for whom the vein cuff was constructed with or without an arteriovenous fistula. But patients who managed with a supplementary arteriovenous fistula had significantly fewer distal residual arteries in the limb (p=0.001). CONCLUSION: Although results in patients treated with adjunctive techniques differed little from those in patients treated with direct prosthetic bypasses procedures, those who eventually had an adjunctive procedure had inferior runoff. This indicates that an arteriovenous fistula might be a valuable supplement in patients with poor runoff who have distal revascularisation using a prosthetic graft.     

Results of prosthetic-vein composite graft with remote popliteal arteriovenous fistula in infragenicular bypass

OBJECTIVE: The purpose of this study is to report the results of a novel procedure for femoral-distal bypass grafting using a composite graft with an adjunctive remote popliteal fistula distal to the prosthetic portion of the graft. This reconstruction was developed for use in limb salvage in the absence of satisfactory autogenous vein. METHOD: Data were collected prospectively on all patients undergoing this procedure from January 1, 1993 to December 31, 1999. Graft patency was determined from follow-up duplex scanning. Patient survival was determined by clinic follow-up. RESULTS: A total of 43 procedures were performed in 38 patients. In 34 patients, 72 previous arterial operations had been previously performed on the ipsilateral limbs. There were 20 men and 18 women with a mean age of 72 years. The indication for surgery was limb salvage in all, with rest pain in 30, and tissue loss in 13. The outflow artery was the below-knee popliteal artery in 10 and a tibial artery in the remainder. Operative mortality was 6.8%. Mean follow up was 26.9 months. The primary patency was 54% at 12 months. Six reconstructions were revised for a primary assisted patency of 60% at 16 months. Secondary patency was 69% at 16 months. Patient survival was 62% at 2 years and 26% at 5 years. CONCLUSIONS: The technique of composite grafting with remote popliteal arteriovenous fistula may be a useful alternative in infragenicular bypass when a satisfactory autogenous vein is not available.     

Infrapopliteal prosthetic graft patency by use of the distal adjunctive arteriovenous fistula

From November 1979 through December 1989, 210 distal arteriovenous fistulas were constructed as adjuncts to tibial and peroneal vascular reconstructive procedures in 203 patients threatened with limb loss. Two-year cumulative patency rates were calculated by grouping patients on the basis of changing indications in sequential time periods: group 1 (n = 61): 1979 to 1983, 18%; group 2 (n = 80): 1983 to 1986, 33%; group 3 (n = 69): 1986 to 1989, 44%. Although the therapeutic results observed in these groups are not statistically comparable, they show a perceptible trend. Postoperative arteriography showed that flow is prograde in the distal vessels beyond the distal arteriovenous fistula. Graft surveillance by duplex ultrasonography also confirmed that flow in the distal arteries is prograde and that "steal" does not occur. Peak systolic velocity (174 +/- 38 cm/sec) and mean velocity (92 +/- 23) flow rates are increased in grafts with patent distal arteriovenous fistulas compared to those bypasses with closed distal arteriovenous fistulas (p less than 0.01). There were no differences in the flow measurements for the arteries beyond the distal anastomoses and distal arteriovenous fistulas, confirming the prograde nature of the distal flow. In 22 patients analysis of graft and fistula patency by duplex sonography showed that one fourth of all grafts were patent without fistulas at 1 and 2 years after operation. Alternatively, 68% of patent grafts at 1 year had patent fistulas and 58% had patent fistulas at 2 years. We conclude that the distal arteriovenous fistula will increase graft flow and simultaneously prevent distal arterial overload without causing "steal." This technique should be considered whenever a prosthetic graft is necessary for crural reconstruction and only in selected instances of revascularization with autologous veins.     

Combined percutaneous transluminal angioplasty and extraanatomic bypass for symptomatic unilateral iliac artery occlusion with contralateral iliac artery stenosis

We have reviewed our experience with percutaneous transluminal angioplasty of contralateral iliac stenosis and extraanatomic bypass of the occluded iliac artery. Twenty-two men and nine women with a mean age of 65 years (range 46 to 84) presented with symptomatic iliac occlusive disease. Twenty-four (77%) had disabling claudication, four (13%) rest pain, and three (10%) ischemic tissue loss. Six (19%) had undergone previous vascular reconstructive procedures. All had an occluded iliac artery on the symptomatic side and greater than 50% stenosis of the contralateral iliac artery. Percutaneous transluminal angioplasty of the iliac stenosis was done prior to extraanatomic bypass, using polytetrafluoroethylene. There were six late deaths after discharge. The only significant complication was a femoral artery thrombosis which was corrected when the bypass graft was performed. Cumulative primary graft patency was 89% at one year and 81% at three years. The crossover graft occluded in six patients, five within 48 months of surgery, and one after nine years. One of these occluded grafts was salvaged by thrombectomy, for a secondary patency rate of 85% at three years. Two patients required aortobifemoral bypass, one an iliobifemoral bypass and one an ilioprofunda bypass. One patient operated upon for rest pain came to below-knee amputation. Mean resting ankle/brachial systolic pressure index increased significantly on the side of the iliac occlusion from 0.35 ±0.21 to 0.70 ± 0.20 (p < 0.05, paired t test) after the combined procedure. There was no significant difference in the mean resting ankle/brachial systolic pressure index on the contralateral side (0.60 ± 0.22 to 0.65 ± 0.27, ns). Combined iliac percutaneous transluminal angioplasty and femorofemoral bypass is a safe alternative to aortobifemoral bypass for selected patients with aortoiliac arterial occlusive disease. Presented at the Royal Australasian College of Surgeons, General Scientific Meeting, May 1989, Melbourne, Australia.     

Polytetrafluoroethylene Femorotibial Bypass Grafting: 5-year Patency and Limb Salvage

For a femorotibial bypass graft the material of choice is autologous vein. The question remains whether prosthetic material is a reasonable alternative for limb salvage, if autologous vein is not available. From 1991 to 1998, 83 consecutive femorotibial bypass procedures were performed in 70 patients. Thin-walled, ringed 6-mm polytetrafluoroethylene (PTFE) was used, as autologous vein was not available. The indication for the femorotibial bypass was critical ischemia due to atherosclerotic occlusive disease in all cases. Three patients died in the hospital or within 30 days of the operation, resulting in a perioperative mortality rate of 3.6%. After 5 years, 33 patients had died (40%) and 3 patients were lost to follow-up (3.6%). Primary patency was 64.2% after 6 weeks and 18% ± 5% after 5 years. Secondary patency was 74.1% after 6 weeks and 22.3% ± 6% after 5 years. When we compared primary and secondary patency for distal anastomosis, there was no difference between the three crural arteries. The limb salvage rate was 61.9% ± 7% after 5 years. From these results we conclude that, with a limb salvage of 61.9%, PTFE is an acceptable alternative for a femorotibial bypass graft in patients with critical ischemia, if autologous vein is not available.     

Reconstruction of the vena cava and of its primary tributaries: a preliminary report

Encouraged by results from our research laboratory and from recent clinical reports, we performed reconstructions of the vena cava and/or its major tributaries on 16 patients (11 males and five females). Ages ranged from 8 to 81 years (median, 38 years). Eight patients had superior vena cava syndrome (benign, six; malignant, two). Two other patients had membranous occlusion of the inferior vena cava; four had iliocaval venous thrombosis; one had excision of the iliac veins for pelvic neurilemmoma; and one had inferior vena cava injury during orthotopic liver transplantation. The superior vena cava was reconstructed with spiral saphenous vein grafts in five patients and with expanded polytetrafluoroethylene in three. One spiral saphenous vein graft and one expanded polytetrafluoroethylene graft required revision; seven of the eight grafts were patent at follow-up, but one bifurcated spiral saphenous vein graft occluded at 3 months. The inferior vena cava and its tributaries were reconstructed with expanded polytetrafluoroethylene in five patients, spiral saphenous vein graft in two, and Dacron in one. At follow-up four of the expanded polytetrafluoroethylene grafts were patent. In contrast, one of the spiral saphenous vein grafts was occluded, and results of imaging studies of the other were inconclusive. Three of the five expanded polytetrafluoroethylene grafts had a concomitant temporary arteriovenous fistula at the groin; two had documented patency at follow-up. At the present time, spiral saphenous vein graft is our first choice for superior vena cava replacement. However, expanded polytetrafluoroethylene grafts are good alternatives and in the abdomen appear to perform better than spiral saphenous vein graft. These clinical results encourage us to perform further caval grafting in selected patients.     

Questionable value of adjuvant arteriovenous fistula in pedal bypass at high risk for early failure

Results of an adjuvant arteriovenous fistula (AVF) in pedal bypass surgery in the presence of poor status of the recipient artery, severely impaired intraoperative runoff, or revision for early failure and flow restitution were analyzed in a retrospective study. From January 1998 to December 2006, 24 adjuvant AVFs were constructed in autologous vein or composite pedal bypasses with low intraoperative bypass flow, poor status of the pedal artery, or during successful early bypass revision to prevent graft failure. All infrainguinal bypass operations were registered in a computerized database and prospectively followed. Pedal bypasses with adjunctive AVF were reviewed for fistula function, graft patency, limb salvage, and patient survival. Primary and secondary bypass patency rates at 1 year were 59% and 77%, respectively, with an AVF patency of 36%. Four legs were amputated despite a patent bypass with patent AVF on three occasions. The corresponding limb salvage rate was 65% at 1 year. Patient survival was 50% at 3 years. Adjuvant AVF constructed in grafts considered at high risk for early failure in pedal vein graft or composite bypass does not seem to prevent future graft failure. In patent bypasses the fistula has a significant tendency for spontaneous occlusion. It may be considered in the use of prosthetic composite pedal grafts in selected cases.     

Durability of the in situ saphenous vein arterial bypass: a comparison of primary and secondary patency

The use of the saphenous vein in situ is associated with unique problems that decrease primary graft patency (patency uninterrupted by revision). During the past 5 years, we have performed 192 in situ saphenous vein bypasses in 182 patients, including 61 to the popliteal artery, 128 to infrapopliteal arteries, and three to isolated popliteal artery segments. The operative indications were critical limb ischemia in 178 cases (93%), popliteal aneurysm in eight cases (4%), and disabling claudication in six cases (3%). A progressive decline in primary patency occurred after operation. The primary patency rate at 36 months was only 48% for femoropopliteal bypasses and was 58% for femorotibial bypasses. In contrast, the secondary patency rate (patency maintained by thrombectomy, thrombolysis, or revision) at 36 months was 89% and 80% for femoropopliteal and femorotibial bypasses, respectively. The improved secondary patency was due to postoperative surveillance of graft hemodynamics and the success of graft revision. Problems unique to the in situ technique (incomplete valve incision, residual arteriovenous fistula, graft torsion and entrapment) accounted for 58% of early (less than 30 days) graft revisions and 52% of late revisions. The use of Doppler spectral analysis at operation and duplex scanning after operation can locate unsuspected technical errors and identify grafts with low flow at increased risk for failure. The primary patency of the in situ bypass mandates objective assessment of valve incision sites at operation and a protocol of postoperative surveillance to identify grafts that require revision. Early surgical intervention of hemodynamically abnormal but patent in situ bypasses is rewarded by excellent secondary patency.     

Treatment of angioaccess-induced ischemia by revascularization.

Upper extremity ischemia related to the construction of a chronic angioaccess is a serious and occasionally devastating complication. Fourteen patients with end-stage renal disease (mean age 58 +/- 18 years, 13 with diabetes, 10 female) had ischemia after construction of an angioaccess. Twelve patients had a polytetrafluoroethylene brachioaxillary bridge arteriovenous fistula (BAVF), one patient had a radiocephalic arteriovenous fistula (AVF) and one patient had a brachiocephalic AVF. All patients had severe ischemia and five of them had established gangrenous changes. Symptoms appeared immediately after construction of the access in 10 patients. The remaining four patients had late onset of ischemia. The technique used for revascularization in all of these patients consisted of ligating the artery just distal to the takeoff of the AVF or BAVF and establishing an arterial bypass from a point proximal to the AVF or BAVF inflow to a point distal to the ligature. Bypass grafts consisted of saphenous vein in 13 cases and polytetrafluoroethylene in one case. Thirteen patients had a complete recovery, including healing of gangrenous lesions. One patient with severe gangrene of the hand at the time of revascularization required forearm amputation 13 months later because of progressive occlusive arterial disease. All AVFs were patent at 1 year. The 1-year patency rate for the BAVFs was 81.7%. All arterial bypasses were patent at 1 year. It is concluded that this technique offers consistent and durable hemodynamic and clinical improvement in arms affected by access-induced ischemia, with minimal morbidity, and does not affect the longevity of the angioaccess.     

Radial artery flow-through graft: a new conduit for limb salvage

OBJECTIVE: Patients with severe peripheral occlusive disease may present especially challenging problems because of previous bypass surgery, location of ulcers, or extremely poor runoff. We used the radial artery with its overlying skin flap as a bypass conduit, called the radial artery flow-through (RAFT) graft in 10 such patients. METHODS: From November 1999 to January 2002, 10 patients had limb-threatening ischemia at presentation. All had severe inframalleolar vascular occlusive disease. Four patients had undergone previous conventional bypass procedures. Two grafts remained patent, but distal ulcers failed to heal. Eight patients were men. Seven patients had diabetes mellitus. All patients but one had nonhealing ulcers. In most cases, a composite femoral-tibial bypass graft was constructed by sewing the RAFT graft end-to-end to either the greater saphenous vein or, in one patient, to a polytetrafluoroethylene graft. In all cases, the radial venous comitans were sewn to a nearby superficial vein. In 5 patients the skin paddle was positioned to cover the ulcer; in the remaining patients the skin paddle was used to close the foot incision over the distal anastamosis. Postoperative graft surveillance was performed with Duplex scanning or contrast medium-enhanced angiography. RESULTS: Thromboses developed in 2 grafts during follow-up. In 1 of these patients below-knee amputation was performed. Another patient required below-knee amputation because of continuing infection in the foot despite a patent RAFT graft. In 1 patient thrombosis developed in the vein graft, but the RAFT graft extension remained patent. All other RAFT grafts were patent in their entirety at 15 (+/-6) months. CONCLUSIONS: The RAFT graft is a new option for treating limb-threatening ischemia. The skin paddle may be useful in selected patients for wound coverage.