Successful conservative therapy of severe limb-threatening ischemia: the value of nonsympathectomy.

Fourteen patients with severely ischemic extremities but relatively minor degrees of pedal gangrene or ulceration were managed without surgery. Contraindications to direct arterial reconstruction included significant intercurrent illness or generally poor surgical risk, the need for reoperative or difficult distal reconstruction, or the favorable characteristics of the actual lesion. Management consisted of bed rest, simple saline soaks, occasional gentle debridement, and antibiotics when indicated. Seven patients had complete resolution of their lesions for 3 to 48 months, and seven had improvement or stabilization for 3 to 18 months. Only three of the 14 patients have eventually required surgery with limb salvage in one. Revascularization remains the method of choice for managing most severely ischemic extremities. However, the conservative approach described represents an alternative to early amputation, attempts at revascularization, or lumbar sympathectomy in some patients with advanced ischemia. Studies of sympathectomy and pharmacologic agents as effective treatment for ischemic ulcers or gangrene should include control groups treated with the conservative measures outlined herein.

Staging of arterial complications of cervical rib: guidelines for surgical management.

Subclavian artery compression by a cervical rib is an uncommon but potentially disabling condition. A series of 12 patients with 15 arterial lesions is reviewed and a staging system proposed to provide guidelines for managing patients with this condition. Stage I lesions have only arterial stenosis and minor poststenotic dilatation and are managed by thoracic outlet decompression, usually consisting of cervical rib resection. Stage II lesions have intrinsic arterial damage usually with subclavian aneurysm formation and require rib resection, aneurysmectomy, and arterial reconstruction. Stage III lesions present with distal thromboembolic complications and require thrombectomy or embolectomy in addition to thoracic outlet decompression and arterial reconstruction. The anatomic and pathophysiologic bases of the syndrome are reviewed and clinical and angiographic examples of each stage are presented.

Comparison of axillounifemoral and axillobifemoral bypass operations.

Routine use of axillobifemoral (ABF) bypass has been advocated because this operation is thought to achieve better patency than the axillounifemoral (AUF) procedure. In 5 years we performed 34 AUF and 22 ABF bypass operations for limb salvage in high-risk patients using 6 mm polytetrafluoroethylene grafts. Five-year cumulative life table patency rates for AUF bypasses were 71% with reoperation (secondary patency) and 44% without reoperation (primary patency). These values were not significantly different (p greater than 0.5) from those for ABF bypasses (77% and 50%, respectively). Five-year limb salvage results (AUF 73%; ABF 89%) were also not significantly different (p greater than 0.1). Correlation of arterial outflow characteristics with graft patency revealed that 78% of the patients who never had graft occlusion had occluded superficial femoral arteries (SFA) demonstrated at the first operation, while 79% of the patients who experienced graft closure had comparable SFA occlusions. Our aggressive approach to graft thrombosis included angiographic study of the inflow arterial system. This revealed that 16% of the failed grafts were associated with hemodynamically significant stenosis of the donor subclavian artery. Our results indicate that AUF bypass is the procedure of choice for unilateral limb ischemia in high-risk patients who require an axillary source and that patency of the SFA does not affect outcome. These results also emphasize the need to obtain angiographic evaluation of the inflow system.

Limb salvage in octogenarians and nonagenarians.

Although advanced age has often been a relative contraindication to attempts at limb salvage, we have not regarded it as an important deterrent to arterial reconstruction. Our 6-year experience with 168 consecutive patients over 80 years of age who underwent arterial reconstruction or percutaneous transluminal angioplasty represented 18% of all patients treated with limb-threatening ischemia during this period. The average age was 84 years, with 14 patients over 90 years of age. Sixty-eight patients were men (41%) and 100 were women (59%). Indications for treatment in 189 limbs were restricted to limb salvage. One hundred eighty-two operative procedures were performed consisting of 84 femoropopliteal, 72 femorotibial, 12 axillofemoral, 11 femorofemoral, two axillopopliteal and one iliofemoral bypass. Percutaneous transluminal angioplasty was performed in 12 iliac and 14 femoral or popliteal arteries as an alternative (seven) or adjunct (19) to vascular reconstruction. The 30-day procedural mortality rate was 6%. The cumulative life table survival rate of all patients who underwent an attempt at limb salvage was 78% at 1 year, 65% at 2 years, and 54% at 3 years. Cumulative life table limb salvage rates were 84% at 1 year, 74% at 2 years, and 71% at 3 years. Overall graft patency for 182 arterial reconstructive operations was 80% at 1 year and 62% at 3 years. Of patients in whom limb salvage was attempted, 65% lived more than 1 year and 51% more than 2 years with a functional limb. Of patients who died within 5 years of treatment, 76% did so with their previously threatened limb intact. These data support an aggressive approach to arterial reconstruction in elderly patients and indicate that advanced age alone should not be considered a contraindication to attempts at limb salvage.

Intrathecal perfusion of an oxygenated perfluorocarbon prevents paraplegia after aortic occlusion.

A canine model was used to evaluate the effects of continuous intrathecal perfusion of an oxygenated perfluorocarbon emulsion on systemic and cerebral hemodynamics and neurologic outcome after 70 minutes of normothermic aortic occlusion. Twelve mongrel dogs were instrumented to monitor proximal and distal arterial blood pressure, cerebrospinal fluid pressure, spinal cord perfusion pressure, and somatosensory evoked potentials. The intrathecal perfusion apparatus consisted of two perfusing catheters, placed in the intrathecal space through a laminectomy, and a draining catheter percutaneously inserted in the cisterna cerebellomedullaris. The aorta was cross-clamped just distal to the left subclavian artery for 70 minutes. Animals were randomized into two groups: group 1 (n = 6) animals were treated with intrathecal perfusion of saline solution, whereas group 2 (n = 6) animals received oxygenated Fluosol-DA 20%. Data were acquired at baseline, during the cross-clamp period, and after reperfusion. Normothermic Fluosol or saline solution was infused at a rate of 15 mL/min beginning 15 minutes before cross-clamping and continued throughout the ischemic interval. There was no difference in proximal arterial blood pressure (97.2 versus 95.4 mm Hg; p > 0.05) or distal arterial blood pressure (14.6 versus 15.0; p > 0.05) between the two groups throughout the cross-clamp interval. Cerebrospinal fluid pressure rose significantly in both groups with the onset of intrathecal perfusion of either saline solution or Fluosol (7 +/- 1 versus 24 +/- 5 and 8 +/- 1 versus 40 +/- 4 mm Hg, respectively; p < 0.05). The rise in cerebrospinal fluid pressure was sustained throughout the perfusion interval in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Infrapopliteal bypasses to heavily calcified rock-like arteries. Management and results.

Of the 355 consecutive infrapopliteal bypasses for limb salvage performed over a 5 year period at our institution, 116 (Group I) were to noncalcified vessels, 203 (Group II) were to vessels of varying degrees of calcification (mild to moderate), and 36 (Group III) were to heavily and circumferentially calcified arteries. A new intraoperative fracture technique was used to overcome the rigidity of the arterial wall in the latter group. Three year cumulative patency rates for Groups I, II, and III were 45 percent, 58 percent, and 47 percent, respectively. Comparable limb salvage rates for Groups I, II, and III were 66 percent, 73 percent, and 75 percent. No significant difference in patency or limb salvage results could be elicited between the three groups by the log-rank test. These findings suggest that arterial calcification is an invalid predictor of failure in small vessel bypasses. Even circumferentially calcified arteries, which are generally thought to be surgically unapproachable, should not be a deterrent to limb salvage attempts.

Reduction of the extent of ischemic skeletal muscle necrosis by perfusion with oxygenated perfluorocarbon.

Oxygenated perfluorocarbon emulsion has been shown to preserve feline cerebral function after ischemia. The postulated protective effects of perfluorocarbons include improvement of blood rheology and prevention of neutrophil adherence by nonchemical inhibition of surface receptors. In this study, we used a well-described gracilis muscle model to investigate whether oxygenated perfluorocarbon can minimize skeletal muscle necrosis by mitigating the degree of leuko-sequestration. In eight adult mongrel dogs, both gracilis muscles were weighed and then subjected to 6 hours of normothermic ischemia followed by 48 hours of normothermic reperfusion. However, one randomly selected side (experimental side) was infused with oxygen (O2) Fluosol-DA 20% (4.4 +/- 0.2 mL O2/100 mL) intra-arterially at 12 mL/min for 40 minutes immediately after ischemia. Muscle biopsy specimens were obtained before ischemia and after 1 hour and 48 hours of reperfusion to estimate myeloperoxidase (MPO) activity, a marker of neutrophil infiltration. After 48 hours, both gracilis muscles were harvested and weighed in all animals. Muscle necrosis was measured by serial transections, nitroblue tetrazolium staining, and computerized planimetry. The transmuscular oxygen tension (pO2) of the gracilis muscle on the experimental side increased from 2 to 4 mm Hg during ischemia to 315 +/- 50 mm Hg during O2 Fluosol-DA 20% infusion. The percentage of muscle necrosis on the control side was 48.08% +/- 8.46%, compared with 27.62% +/- 6.96% on the experimental side (p less than 0.001). MPO activity was significantly higher at 48 hours of reperfusion compared with pre-ischemic and 1-hour reperfusion values (5.46 +/- 1.52 U/mg tissue protein versus 0.06 +/- 0.01 U/mg tissue protein and 0.16 +/- 0.06 U/mg tissue protein, respectively, in the control group; 1.78 +/- 0.60 U/mg tissue protein versus 0.16 +/- 0.08 U/mg tissue protein and 0.27 +/- 0.10 U/mg tissue protein, respectively, in the experimental group, p less than 0.05). However, MPO activity at 48 hours of reperfusion in the experimental group was significantly lower than in the control group (p less than 0.05). There was no difference in the percentage of weight gain between the control and the experimental groups (38.31% +/- 9.36% and 28.34% +/- 7.35%, respectively, p greater than 0.05). These data show that perfluorocarbons minimize the extent of skeletal muscle necrosis in this canine model. Based on our data on MPO activity, we believe t hat the protective effect of perfluorocarbons is in part due to th e decreased leuko-sequestration in the muscle during the the periods of ischemia and reperfusion.(ABSTRACT TRUNCATED AT 400 WORDS)

Noninvasive predictors of patency for infrapopliteal PTFE bypasses with combined arteriovenous fistula and vein interposition technique.

BACKGROUND: Despite recent increased indications for infrapopliteal prosthetic bypass grafts with complementary arteriovenous fistulas, objective documentation of improved perfusion to the foot is lacking. In addition, the value of post operative noninvasive testing in the prediction of bypass success remains unclear. PATIENTS AND METHODS: Over a 3-year period, 41 patients with limb-threatening ischemia were treated with 41 infrapopliteal 6-mm polytetrafluoroethylene (PTFE) bypasses with a complementary arteriovenous fistula at our institution. Twenty-four patients were men and 17 were women, with an average age 71.3 +/- 8.6 years. Thirty-one patients (76%) had undergone at least 1 previous failed ipsilateral arterial bypass. Preoperative and early postoperative (less than 1 month) pulse-volume recordings of transmetatarsal amplitude (TMA) were available for analysis in 28 patients. Postoperative duplex evaluations of graft velocity, fistula patency, and prograde distal arterial flow were performed in 26 of the original 41 patients. These data were correlated to early graft failure in an attempt to identify specific noninvasive predictors. RESULTS: Cumulative primary patency rates of the original 41 patients were 79.0%, 69.2%, and 63.8% at 1, 2, and 3 years, respectively. The early postoperative TMA values ranged from 3 to 50 mm with a mean of 21.6 +/- 14.8 mm (P < 0.001). Twenty-one patients (75%) had patent grafts on follow-up of 2 to 37 months (mean 18.6). The early postoperative TMA in this group of patients was 26.5 +/- 12.4 mm compared with 3.3 +/- 2.8 mm in the 6 patients whose grafts failed within 6 months (P < 0.001). A TMA of < 5 mm was 83% sensitive and 95% specific for the prediction of early graft failure. Of the graft examined by duplex ultrasonography, 21 (81%) remained patent during the follow-up period. The midgraft peak systolic velocity (PSV) of these grafts was 109 +/- 8.0 cm/s compared with 74.2 +/- 15.3 cm/s for the 5 initially patent bypasses that subsequently failed at any time during the follow-up period (P < 0.05). PSV of < 70 cm/s was 60% sensitive and 86% specific in predicting early graft failure. The combination of early postoperative TMA < 5 mm and early midgraft PSV < 70 cm/s was 100% sensitive and 100% specific for the prediction of early graft failure. CONCLUSIONS: These data show that infrapopliteal PTFE arterial bypasses with complementary arteriovenous fistulas significantly improve arterial perfusion at the level of the foot in the majority of patients. Also, both the postoperative TMA and midgraft PSV appear to be reliable predictors of graft outcome. Further experience with the noninvasive surveillance of these bypasses may become as rewarding as it is in standard vein bypasses.

Evaluation of graft patency utilizing the ankle-brachial pressure index and ankle pulse volume recording amplitude.

To determine femoropopliteal graft patency, the ankle-brachial pulse index and the ankle pulse volume recording amplitude were measured. Fourteen healthy volunteer subjects were tested on two occasions over 24 hours (ankle-brachial pressure index 1.14+:-0.16, change 0.03+:-0.05; ankle pulse volume recording amplitude 25+:-7 mm, change 5+:-4 mm). In the second control group, hemodynamic function in the unoperated limb was studied before and after surgery in 40 patients undergoing infrainguinal bypass on the contralateral side (preoperative ankle-brachial pressure index 0.66+:-0.3, change 0.02+:-0.12; preoperative ankle pulse volume recording amplitude 8+:-7 mm, change 1+:-3 mm). After 119 patent femoropopliteal bypasses ankle-brachial pressure index and ankle pulse volume recording amplitude increased by 0.41+:-0.26 and 11+:8 mm, respectively.

Outflow resistance measurement during infrainguinal arterial reconstructions: a reliable predictor of limb salvage.

Criteria for abandoning infrainguinal arterial reconstructions in favor of major amputations should include reliable predictors not only of graft patency, but more importantly, of limb salvage. To evaluate the efficacy of intraoperative outflow resistance measurements in predicting limb salvage after infrainguinal bypasses, we have reviewed 134 such operations (64 femoropopliteal and 70 femorodistal bypasses) performed for critical ischemia. Outflow resistance measurements were divided into quartiles for femoropopliteal bypasses (Group A 0.17 mm Hg/ml/min or less, Group B 0.18 to 0.24 mm Hg/ml/min, Group C 0.25 to 0.4 mm Hg/ml/min, and Group D greater than 0.4 mm Hg/ml/min) and femorodistal bypasses (Group A 0.4 mm Hg/ml/min or less, Group B 0.4 to 0.58 mm Hg/ml/min or less, Group C 0.6 to 1 mm Hg/ml/min, and Group D 1 mm Hg/ml/min or greater). One year limb salvage rates for patients who underwent femoropopliteal bypass were 95 percent, 92 percent, 87 percent, and 67 percent from the lowest to the highest quartile (difference not statistically significant), and for those who had femorodistal bypass, they were 51 percent, 75 percent, 48 percent, and 0, respectively (p less than 0.05). Interestingly, 12 month graft patency and limb salvage rates for patients who underwent femorodistal bypass with outflow resistances between 0.59 and 1 mm Hg/ml/min did not correlate well (22 percent and 48 percent, respectively), whereas for those with outflow resistance greater than 1 mm Hg/ml/min, they were 22 percent and 22 percent, respectively. Thus, measurement of intraoperative outflow resistance is a very accurate predictor of limb salvage after infrainguinal bypass operations.

Inadequacy of the noninvasive hemodynamic evaluation of percutaneous transluminal angioplasty.

The role of noninvasive hemodynamic tests in the evaluation of percutaneous transluminal angioplasty success or failure was studied. The ankle-brachial pressure index and pulse volume recording amplitude were measured before and after 37 iliac and 46 femoropopliteal angiographically successful percutaneous transluminal angioplasties. Immediate evidence of hemodynamic improvement was seen in 53 percent of angiographically successful dilatations using the ankle-brachial pressure index and in 60 percent using the pulse volume recording amplitude alone. A better correlation was seen when improvement was noted on either test but was still only 71 percent. Twelve primary iliac percutaneous transluminal angioplasties were considered to be successful immediately by angiography, yet no hemodynamic improvement was recorded. Nine primary iliac percutaneous transluminal angioplasties, however, had continued clinical success and limb viability. Twelve angiographically successful femoropopliteal percutaneous transluminal angioplasties also showed no improvement in hemodynamic values, yet three have continued clinical evidence of patency. Thus, although noninvasive hemodynamic tests are important and must be carried out, they are only one of many ways to assess the effectiveness of angioplasty.

Acute mesenteric ischemia after cardiopulmonary bypass.

Three thousand sixty-six patients underwent cardiopulmonary bypass at the Maimonides Medical Center over a 5-year period from January 1, 1987, to January 1, 1992. Of these patients, 1,890 (62%) were less than 70 years of age, 969 (32%) ranged from 70 to 79 years of age, and 207 (7%) were 80 years of age or older. The overall 30-day mortality rate was 8%. Eleven patients developed acute mesenteric ischemia from 24 hours to 12 days postoperatively. At the time of diagnosis, the majority of patients presented with late classical signs and symptoms of acute mesenteric ischemia including abdominal distension, respiratory distress, hypotension, oliguria, and sepsis. All patients underwent immediate laparotomy. Extensive bowel necrosis was found in all, and resection was possible in eight patients. All patients died as a result of this complication. Using the exact trend test, we found a statistically significant increase in the incidence of deaths due to acute mesenteric ischemia after cardiopulmonary bypass in older compared with younger patients. This fatal complication after cardiopulmonary bypass occurs more often than previously believed and is a relatively common cause of death in the elderly.

The relationship between timing of repair of disruptions and subsequent aneurysm formation in laser-assisted microvascular anastomoses.

In this study we investigated the effects of duration of bleeding after laser-assisted microvascular anastomoses and the amount of laser energy used to control bleeding on aneurysm formation. Eighty femoral arteries were exposed in 40 Sprague-Dawley rats anesthetized with chloral hydrate. The arteries were transected and then anastomosed end-to-end with three nylon stay sutures followed by irradiation of the vessels with energy from a CO2 laser. The laser power was kept at 90 mW, and each of three segments between stay sutures was exposed for 6 seconds to continuous laser energy. If anastomotic disruption (defined as bleeding after completion of the anastomosis) occurred, it was controlled with pressure over the disrupted site for 10, 25, or 40 seconds. Disruptions were required with exposure to additional laser energy for either 6 (group 1) or 12 seconds (group 2). The anastomoses were inspected at 21 days postoperatively to assess patency and aneurysm formation. Twenty-six of 80 vessels (32%) were anastomosed without the occurrence of disruptions: these 26 vessels had a 100 per cent patency rate and did not develop aneurysms. In group 1, the incidence of redisruption following a primary disruption was the same irrespective of duration of bleeding (4/8, 3/6, and 3/6 for 10-, 25-, and 40-seconds bleeding time, respectively P = NS). Similarly, there was no difference in the incidence of aneurysm formation in this group (0/8, 2/6, and 2/6 for 10, 25, and 40", respectively, P = NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Do cytokines play a role in skeletal muscle ischemia and reperfusion?

Cytokines, interleukin-1 (IL-1) and tumor necrosis factor (TNF) are known to mediate host cell response to sepsis, trauma, and myocardial ischemia. We have previously found increased levels of IL-1 in the venous effluent during the reperfusion phase of skeletal muscle ischemia in a canine model. This study was done to evaluate whether TNF also played a role in skeletal muscle ischemia-reperfusion injury since IL-1 and TNF have inter-related functions. In twelve adult mongrel dogs (28-32 kg) one gracilis muscle was subjected to six hours of normothermic ischemia followed by normothermic reperfusion. The contralateral side served as a control and remained normally perfused throughout the experiment. Gracilis venous samples were collected at pre-ischemia and one hour of reperfusion. Systemic (arterial) blood samples were taken simultaneously with the venous samples at one hour of reperfusion. At the end of the experiment the muscles were harvested and amount of necrosis quantitated by serial transections, nitroblue tetrazolium staining and computerized planimetry. Muscle necrosis on the experimental side was found to be 48.86 +/- 5.37%. Sera were analyzed for TNF activity using a bioassay. TNF levels in the gracilis venous effluent at one hour of reperfusion were not significantly different from the simultaneous systemic (arterial) levels (27.15 +/- 5.05 pg/ml vs 18.23 +/- 4.27 pg/ml). Pre-ischemic levels of TNF were 96.50 +/- 20.12 pg/ml, which was significantly higher than either venous or arterial levels obtained after one hour of reperfusion (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of adjunctive arteriovenous fistula on prosthetic graft patency: a controlled study in a canine model.

Bilateral 6 mm PTFE grafts were placed from the external iliac artery to the femoral artery with ligation of the intervening segment of the iliofemoral artery in 14 dogs. An arteriovenous fistula was constructed at the distal anastomosis on one randomly selected side in each animal while the contralateral graft served as a control. Graft follow-up ranged between 8 and 12 months in all animals. Serial arteriography was performed to confirm graft and fistula patency and demonstrated persistence of antegrade flow into the arterial tree distal to all patent bypasses. Femoral intraarterial pressures distal to patent grafts were identical on both sides in each animal throughout the study. Cumulative life-table patency rates showed higher patency for the arteriovenous fistula bypasses than the control grafts at all time intervals: 71% vs. 57% at 3 months, 48% vs. 25% at 6 months, and 40% vs. 22% at 12 months, respectively. This is the first controlled study that provides experimental evidence suggesting that these bypasses may produce increased patency of prosthetic arterial grafts and lends support to their use in a clinical, prospective, randomized study.

Photoplethysmographic evaluation of external compressive therapy for chronic venous ulceration.

The photoplethysmograph (PPG) was utilized to evaluate the role of external compression in the treatment of chronic venous insufficiency with ulceration (CVIU). Thirty patients with long standing CVIU were evaluated using a PPG probe placed just above the medial malleolus. Venous recovery time (VRT) was calculated after 5 active dorsiflexions. Patients were then retested after an Unna boot had been applied and again, after this had been supplemented by a tight elastoplast wrap. VRT in 10 normal control subjects was greater than 12 seconds (12-30 seconds, mean 19+/-5 seconds). VRT was less than 12 seconds in all tested patients (0-11 seconds, mean 5+/-2 seconds). When an Unna boot was applied, VRT increased to 7+/-2 seconds in 20 patients. An Unna boot and elastoplast wrap increased VRT to 10+/-3 in 25 patients (p less than 0.01).

Does iloprost mediate thromboxane activity and polymorphonuclear leukocyte sequestration in ischemic skeletal muscle?

Thromboxane is known to alter the endothelial cytoskeleton, thereby causing increased endothelial permeability and polymorphonuclear leukocyte (PMN) sequestration in the lungs. We investigated whether iloprost (a stable prostacyclin analog) can decrease thromboxane activity and consequently PMN sequestration because of its anti-platelet aggregation effect. This premise was investigated in a canine isolated gracilis muscle model using 18 animals. Six animals (group I) had the gracilis muscle subjected to 6 hours of complete ischemia followed by 48 hours of reperfusion. Group II (n = 6) received intravenous infusion of iloprost (0.45 micrograms/kg/hr) throughout the experiment (1 hour preischemia, 6 hours of ischemia and 1 hour of reperfusion) and boluses of 0.45 micrograms/kg 10 minutes before ischemia and reperfusion. Group III (n = 6) underwent a similar ischemic interval, but were given iloprost bolus of 0.45 micrograms/kg followed by intravenous infusion of 0.45 micrograms/kg/hr during 48 hours of reperfusion. Gracilis venous samples were obtained at preischemia (PI) and 1 hour of reperfusion (all 3 groups) and at 48 hours of reperfusion (groups I and III) to measure thromboxane (TXB2) levels. Muscle biopsies were taken at the same time to measure myeloperoxidase (MPO) activity, a marker of PMN infiltration. In group I, TXB2 level increased from a pre-ischemic value of 2983 +/- 1083 pg/ml to 9483 +/- 2218 pg/ml at 1 hour of reperfusion (p < 0.05) and then decreased to 2386 +/- 1533 pg/ml at 48 hours of reperfusion (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Six year experience with expanded polytetrafluoroethylene arterial grafts for limb salvage.

We have used 822 polytetrafluoroethylene (PTFE) grafts in arterial reconstructions for limb salvage over the last 6 years at Montefiore Medical Center-Albert Einstein College of Medicine, Four hundred and twenty-seven femoropopliteal reconstructions with PTFE had a 6 year cumulative life table patency rate of 55% with follow-up of 76 grafts for more than 3 years and 28 grafts for more than 4 years. Seventy-nine bypasses to the isolated popliteal segment had a 6 year cumulative patency rate of 72%. There were 207 bypasses performed to the tibial, peroneal or dorsalis pedis arteries. Life table patency rates were 55% at 1 year, 40% at 2 years and 37% at 4 years. Ninety-two PTFE femorofemoral and 62 axillofemoral bypasses had 5 1/2 year cumulative life table patency rates of 83% and 75%, respectively. Axillopopliteal PTFE bypasses can salvage otherwise doomed limbs. Thirty-four such grafts had 74% 1 year and 45% 5 year patency rates. The overall infection rate in all 822 PTFE grafts was only 0.5%. Thus, PTFE is a promising vascular prosthetic material which facilitates otherwise difficult or impossible limb salvage procedures.

Diagnosis and management of failing lower extremity arterial reconstructions prior to graft occlusion.

In 191 instances, infrainguinal graft occlusion was presumed because of a rethreatened foot, diminished pulses and/or decreased ankle pressure. Routine urgent arteriography revealed 38 instances where the graft was patent (22 vein, 16 PTFE). Ten of these grafts were to the femoral artery, 18 to the popliteal artery and 10 were to infrapopliteal arteries. The deterioration despite a patent graft was due to development of inflow stenosis (15), vein graft lesions (13) or distal disease progression (10). All were treated successfully by percutaneous transluminal angioplasty (30) or simple local operative revisions (8). Cumulative life table patency rates 2 years after reintervention were 89% for failing reconstructions to the femoral artery, 94% for those to the popliteal artery and 89% for infrapopliteal procedures. Comparable rates for limb salvage were 90%, 100% and 100%, respectively. These findings underscore the importance of urgent angiography in suspected lower extremity graft failure. Defects may be detected before real graft occlusion occurs and appropriate interventional treatment can provide important additional periods of limb salvage.

Five year experience with axillopopliteal bypasses for limb salvage.

Over the last 5 years, we have performed 34 axillopopliteal bypasses to salvage threatened limbs of patients in whom standard anatomic or extra-anatomic bypasses had either failed or were not feasible. The indications for these axillopopliteal bypasses, all of which were performed with 6 mm polytetrafluoroethylene grafts, were: (1) severe atherosclerotic disease of the common, superficial and deep femoral arteries which precluded use of these vessels for inflow or outflow for a standard vascular procedure (15 cases); (2) failed aortofemoral bypass with sufficient fibrosis or disease progression in the profunda femoris artery to prevent its use in a reoperation (7 cases); (3) insufficient hemodynamic improvement and failure to heal a foot lesion after an axillofemoral bypass (9 cases); and (4) sepsis in the groin from a previously infected bypass (3 cases). Graft patency was determined by objective measures. Cumulative life table graft patency rates were 77% at 1 year, 51% at 3 years, and 45% at 5 years. Although these rates are not as good as those for our axillofemoral bypasses (75% at 5 years), 22 limbs revascularized by axillopopliteal bypasses were salvaged with function for 1 year and 9 were salvaged with function for 2 years or longer in situations in which no option other than amputation was available. This justifies the continuing use of axillopopliteal bypass in an effort to salvage those limbs imminently threatened with amputation and in which no standard reconstruction is feasible because of disease or infection.