Reliability of intraoperative flow measurements to determine early graft patency with simultaneous introduction of a new method for distal coronary artery run-off capacity

Intraoperative measurements of blood flow were made in 44 patients in whom a total of 112 venous bypass grafts were inserted. Blood flow through the graft was measured by a standard electromagnetic device as well as by a new method, consisting of a roller pump run-off system. At an average of 5 months after operation all patients underwent control coronaro-angiography. Overall patency-rate was 86.6%. Using the standard method mean flow in the patent grafts was 78 ml/min and 39 ml/min in the occluded grafts. Using the new run-off method mean flow in the patent grafts was 142 ml/min and 78 ml/min in the occluded grafts. It is concluded that measuring distal coronary artery run-off capacity provides a reliable index for predicting patency rate. For several reasons roller-pump run-off measurement has advantages over the generally used electromagnetic measurements.     

Collateral back pressure—Is it a valid predictor of infrainguinal bypass graft patency?

While it is generally thought that collateral back pressure (CBP) is a reliable predictor of graft patency, this correlation has not yet been validated. We have used a new, simple technique to measure CBP without direct puncture of the recipient artery. After the distal anastomosis is completed, the graft is filled with saline and clamped proximally. A transducer connected needle is then inserted into the distal portion of the graft for CBP measurements (mm Hg). These were obtained in 84 grafts (43 femoropopliteals [FP] and 41 femorodistals [FD]). Outflow resistance (OR) measurements (mm Hg/ml/min) were also obtained in 70 (36 FP; 34 FD) of these grafts by a previously described technique. The mean CBP for FP and FD bypasses was 41 +/- 17 and 26 +/- 19 mm Hg, respectively (P less than 0.001). Although early graft patency (3 months) (13 occluded, 71 patent) did not correlate with angiographic findings of popliteal runoff or integrity of pedal arch, it did significantly relate to CBP. Mean CBP for occluded grafts was 22 +/- 17 mm Hg and for patent grafts it was 36 +/- 19 mm Hg (P less than 0.01). Similarly, mean OR was significantly related to patency, 1.29 +/- 0.23 mm Hg/ml/min for occluded grafts and 0.36 +/- 0.23 mm Hg/ml/min for patent grafts (P less than 0.0001). Moreover, only OR was a significant predictor of infrapopliteal graft patency (P less than 0.01). OR was found to be a better predictor of graft patency than CBP by stepwise logistic regression analysis (P less than 0.0001). We conclude that CBP is a more reliable predictor of graft outcome than angiographic criteria.(ABSTRACT TRUNCATED AT 250 WORDS)     

Anastomotic arteriovenous fistulae--are they worth it?

An adjuvant distal arteriovenous fistula (ADAVF) has been claimed to increase arterial bypass graft flow and patency when run-off is poor but others have suggested that a patent fistula does not improve in distal limb perfusion. In 10 dogs, hind limbs were rendered ischaemic by proximal arterial ligations and then revascularised with vein grafts. In each dog an ADAVF was constructed on the left graft while the right was used as a control. Flow and pressure were measured in each graft and distal artery and the effect of temporary occlusion and release of the fistula noted. These measurements were repeated at re-operation 3 months later. Mean flow through control grafts was 83 +/- 8.57 (S.E.M.) ml/min, increasing to 146 +/- 22.89 (S.E.M.) ml/min with papaverine (P less than 0.001, Student's t test), and was unchanged at 3 months. Mean flow in grafts with a distal A-V fistula was 250 +/- 41.68 (S.E.M.) ml/min with no change after papaverine, and an increase to 730 +/- 110.5 (S.E.M.) ml/min at 3 months (P less than 0.001, Student's t test). However, arterial flow distal to the fistula was invariably retrograde at initial operation (20 +/- 3.0 S.E.M. ml/min), and this retrograde flow increased to 180 +/- 33.2 (S.E.M.) ml/min at 3 months (P less than 0.001, Student's t test). Distal arterial pressure at initial operation fell from 88.8 +/- 3.35 (S.E.M.) mmHg to 10.8 +/- 1.01 (S.E.M.) mmHg with the fistula open. We conclude that in this animal model an adjuvant distal arteriovenous fistula may improve bypass graft flow, but is unlikely to benefit distal limb perfusion.     

The role of intra-operative Prostavasin application during crural bypass surgery

INTRODUCTION: The aim of this study was to evaluate the role of intra-operative Prostavasin application during crural bypass surgery. 68 Patients, who underwent infrainguinal autologous vein bypass surgery, were prospectively analyzed. RESULTS: Intra-operative flow measurements and Prostavasin administration were performed in all patients. The mean flow was 105 ml / min (minimal flow 18 ml / min, maximal flow 321 ml / min). The means of maximal and minimal flow were 329 und 30 ml / min, respectively. The mean of the calculated Pulsatility index was 3.1. The mean flow volume increased after administration of Prostavasin in all patients with a mean increase of 103 %. The Pulsatility index decreased by 39 %. Primary and secondary patency rates after 1 year were 70.3 % und 73.1 %, respectively. The differentiated analyses of the region of the distal anastomoses (popliteal / crural) showed a statistically significant bigger increase of Q after Prostavasin application for infrainguinal popliteal bypasses compared to patients with crural reconstructions (p = 0.05). In addition, the decrease of the Pulsatility index was significantly higher in popliteal grafts (p = 0.03). Patients with early bypass graft failure showed a significantly smaller decrease of PI after Prostavasin application compared to the other patients. CONCLUSION: The profit of intra-operative arterial Prostavasin application is first of all an immediate one. The injection of Prostavasin leads to an instant vessel dilatation. This allows the surgeon to get an impression of the flow capacity of the bypass. The Pulsatility index as an indicator for resistance is an important factor for bypass patency.     

Distal in situ saphenous vein grafts for limb salvage. Increased operative blood flow and postoperative patency

Early failure remains a major obstacle to successful distal bypass surgery using vein grafts for limb salvage. Thirty distal bypass graft procedures were performed for limb salvage using the in situ technique. Grafts were anastomosed to the distal popliteal artery in 13 patients and to the infrapopliteal artery in 17 patients. Sixteen patients had inadequate saphenous veins for reversed vein grafts. The mean blood flow measured through these grafts (n = 20) was 164 +/- 22 ml/min and increased to 278 +/- 31 ml/min after administration of 30 mg of papaverine. All grafts were patent at the time of hospital discharge and patients were followed for 1 to 28 months. Life table analysis of the 30 procedures shows a patency of 100 percent at 18 months follow-up. One graft subsequently failed at 22 months. Long-term limb salvage was achieved in 100 percent of the patients in this series. The excellent blood flow through these grafts suggests that the in situ vein graft technique may be more favorable for arterial reconstruction than the reversed vein graft technique. Our preliminary data confirm the observations of Leather et al [3,4], that the rates of vein utilization and graft patency are higher with the in situ technique.     

Augmentation of coronary bypass graft flow induced by dipyridamole and its relation to bypass graft patency

To evaluate the effect of dipyridamole on coronary bypass graft flow, 10 mg of dipyridamole was injected intravenously, during the measurement of graft flow, at the time of surgery. Its concentration in serum was measured and compared with that after oral administration. In 50 individual vein grafts performed on 35 patients, graft flow increased from 65 +/- 37 to 96 +/- 55 ml/min (p less than 0.001) after the dipyridamole injection and the arterial pressure decreased slightly. In 40 grafts whose graft flow was increased by more than 10 ml/min by dipyridamole, the patency rate (at 5 weeks) was 98 per cent, whereas that of the 10 other grafts, which responded poorly, was only 50 per cent (p less than 0.01). The serum concentration of dipyridamole, 3 minutes after intravenous injection, was 1.46 +/- 0.68 micrograms/ml, while the level of orally administered dipyridamole, in 3 groups of patients who were given 50 mg, 75 mg and 100 mg, three times a day, respectively, was steady, being 0.68 +/- 0.20 micrograms/ml, 1.43 +/- 0.41 micrograms/ml and 1.73 +/- 0.50 micrograms/ml, 2 hours following ingestion. We concluded that intravenous dipyridamole increases the graft flow and that a better patency is obtained in those grafts in which the graft flow is increased by more than 10 ml/min. It is also expected that routine doses of oral dipyridamole possibly increase the graft flow after coronary bypass surgery.     

Diabetic gangrene in peripheral vascular occlusion. Saving the extremity by popliteo-pedal venous bypass]

23 patients with diabetic gangrene and complete occlusion of all 3 tibial arteries were treated by 26 popliteopedal vein bypass grafts. All 6 early graft failures resulted in major amputations. The cumulative graft patency rate was 76% after 6 years. One patient needed lower-leg amputation despite a functioning graft. All other limbs were saved (mean follow-up period: 24.8 months). It is concluded that despite a palpable popliteal pulse an angiographic examination should be performed, when the infectious lesion cannot be controlled by local treatment and pedal pulses are absent.     

Sequential grafts for limb salvage in the presence of widespread occlusive vascular disease. A review of twenty patients.

Twenty patients with widespread occlusive vascular disease received sequential bypass grafts for lower-limb salvage. In 16 patients an isolated common femoral or profunda segment was perfused by a proximal graft and run-off was augmented by femoropopliteal bypass. In 4 a femoropopliteal bypass constituted the proximal component perfusing an isolated popliteal segment, run-off being increased by a popliteal-to-tibial graft. Dacron, expanded polytetrafluoroethylene (PTFE) (Gore-Tex), and autogenous vein grafts were used. The mean period of follow-up was 10.6 +/- 7 months and 70% of the limbs were salvaged. Thirteen graft systems remain currently patent, 4 have thrombosed, 2 patients died with patent grafts, and 1 required amputation despite graft patency.     

Late results of two hundred seventeen femoropopliteal bypasses to isolated popliteal artery segments

A 10-year-experience of 217 femoropopliteal bypasses to isolated popliteal artery segments in 207 patients is reported. Thirty-three femoropopliteal bypasses (15%) were performed with reversed saphenous vein and 184 (85%) with polytetrafluoroethylene grafts. Operative indications were gangrene in 121 (56%), nonhealing ulceration in 40 (18%), ischemic rest pain in 51 (24%), and claudication in 5 (2%) cases. The 5-year primary graft patency rate of these bypasses was 59% (reversed saphenous vein, 74%; polytetrafluoroethylene, 55%; p less than 0.05), the secondary 5-year graft patency rate was 61% (reversed saphenous vein, 79%; polytetrafluoroethylene, 56%; p less than 0.05), and the 5-year limb salvage rate was 78% (reversed saphenous vein, 78%; polytetrafluoroethylene, 78%). The 30-day operative mortality rate was 10%, and the 5-year patient survival rate was 38%. Eleven patients (5%) required lower extremity amputation because of progressive gangrene or extensive infection despite a patent bypass to an isolated popliteal artery segment. We conclude that femoropopliteal bypasses to isolated popliteal artery segments (1) have acceptable 5-year graft patency and limb salvage rates; (2) should be performed with reversed saphenous vein grafts when possible; (3) may be performed with polytetrafluoroethylene grafts if necessary, with a resulting limb salvage rate equal to that of reversed saphenous vein grafts; and (4) require sequential extension to an infrapopliteal artery in up to 20% of patients. In addition, the presence of an isolated popliteal artery segment is associated with a high operative mortality rate and limited life expectancy because of coronary artery disease.     

Similarity between internal thoracic artery and gastroepiploic artery graft: pharmacological point of view

The pharmacological responses of internal thoracic artery (ITA), gastroepiploic artery (GEA) and saphenous vein (SV) obtained from patients receiving coronary artery bypass grafting (CABG) were assessed by isometric contraction records. The concentration-response curves for ergonovine and serotonin showed the leftward shift in SV compared with ITA and GEA. The 50% effective dose values of SV for ergonovine and serotonin were significantly less than those of ITA and GEA. The concentration-response curves for phenylephrine were similar among three kinds of grafts. There were no significant differences in the 50% effective dose values for phenylephrine among them. The effect of 0.4% papaverine chloride on the free graft flow was assessed in 15 patients receiving CABG with mean body surface area of 1.62 +/- 0.12 M2. The free flow of ITA graft was 71 +/- 32 ml/min before intraluminal papaverine injection, and that increased to 112 +/- 41 ml/min after injection. The free flow of GEA graft was 82 +/- 39 ml/min before injection, and that also increased to 128 +/- 40 ml/min after injection. The patency rates at the mean 2.2 months after grafting were 98% in ITA, 93% in GEA, and 88% in SV. In conclusion, both GEA graft and ITA graft can be expected as an excellent conduit in myocardial revascularization.     

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.     

The contribution of valves to saphenous vein graft resistance

Saphenous vein resistance influences graft flow rates and may affect graft patency in lower limb revascularization. To quantitate specifically the contribution of saphenous vein valves to this resistance, 10 human saphenous veins (mean length 68 cm, diameter 0.42 mm, and 5.2 valves per vein) were perfused with water under carefully controlled pressure gradients designed to simulate different peripheral resistances in the outflow bed. The Reynolds number was maintained at 350 to 600, within the physiologic range for in vivo grafts. Veins were perfused under both venous (10 mm Hg) and arterial (100 mm Hg) mean pressures to determine the effects of distension on the overall resistance of the conduit. The valves were bisected according to Leather's techniques and flow was measured in both directions, antegrade (simulating "reversed" grafts) and retrograde (simulating "in situ" grafts). Data (mean +/- standard error) were normalized to the baseline flow for each vein with intact valves and expressed as a percentage change. Data were analyzed by means of Student's t test (p less than 0.05). Baseline antegrade flow with intact valves averaged 71.0 +/- 3.0 ml/min at pressure gradients (delta P) of 10 mm Hg and 95.0 +/- 2.6 ml/min for delta P = 20 mm Hg. After valve incision, antegrade flow (reversed) increased an average of 29% at both pressure gradients. Retrograde flow (in situ) through the bisected valves was only 19% greater than baseline antegrade flow and was significantly less than antegrade flow through bisected valves. The difference is explained by theoretic considerations of stenosis area and orifice shape. The increases in flow did not correlate with vein length or diameter, nor did flow change with different distension pressures.(ABSTRACT TRUNCATED AT 250 WORDS)     

Femoro-popliteal versus femoro-distal bypass grafting for limb salvage in patients with an "isolated" popliteal segment

In a prospective, multicentre trial, 59 patients with an ischaemic limb and an "isolated" popliteal segment on angiography were randomised to undergo infrainguinal bypass grafting to either the popliteal segment or to a reconstituted distal vessel lower in the calf. Limb salvage was attained with 88% of the femoro-popliteal grafts and 80% of the femoro-distal grafts. There was no difference in the one year graft patency rate between the femoro-popliteal group (79%) and the femoro-distal group (70%). Mean postoperative increase in ankle/brachial pressure index was similar in the two groups despite the presence of occluded or significantly diseased vessels distal to the popliteal anastomoses. Technical difficulties were encountered in 8% of the popliteal group and 24% of the distal group. Femoro-distal bypass grafting confers no apparent benefit over femoral bypass grafting into a patent popliteal segment, even though the popliteal run-off is impaired or occluded.     

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.     

A twelve-year experience with the popliteal-to-distal artery bypass: the significance and management of proximal disease.

The value of the popliteal-to-distal artery bypass in limb salvage is well documented. However, the influence of progression of disease in the superficial femoral artery or proximal popliteal artery, and the role of percutaneous transluminal angioplasty of these vessels before bypass have not been adequately assessed. To evaluate these and other factors, we reviewed our experience with 153 nonsequential popliteal-to-distal artery bypasses performed over a 12-year period. Limb salvage was the indication for all procedures, and 87% of the patients were diabetic. The 5-year primary and secondary graft patency rates were 55% and 60%, respectively, and the limb salvage rate was 73%. Preoperative arteriograms were evaluated for stenosis in the superficial femoral artery or popliteal artery proximal to the graft. Fifty-six grafts with a proximal stenosis 20% or less were identified and had primary graft patency of 77% at 2 years, similar to the 70% patency for the 20 grafts placed distal to a 21% to 35% stenosis. The 18 grafts placed distal to a stenosis greater than 35% had 53% 2-year primary graft patency (p = 0.25). Percutaneous transluminal angioplasty of a superficial femoral artery or popliteal artery stenosis (24% to 85% luminal narrowing) in 19 limbs resulted in 68% 2-year graft patency, not significantly lower than grafts with 35% or less proximal stenosis (75%, p = 0.25). Other factors associated with significant decreases in graft patency included a vein graft diameter less than 3.0 mm, a dorsalis pedis outflow site, and poor quality outflow. Thus the popliteal-to-distal bypass is a durable procedure.(ABSTRACT TRUNCATED AT 250 WORDS)     

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 ‘femorobitibial’ 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 in 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.     

In situ saphenous vein for lower extremity revascularization.

BACKGROUND. During a 6-year period, 349 in situ saphenous vein bypass grafts were performed for limb salvage by three surgeons. METHODS. Outflow anastomoses were constructed to the infrageniculate popliteal (25%), posterior tibial (20%), peroneal (20%), anterior tibial (19%), and dorsal pedal arteries (7%). Mean patient age was 70 1/2 years. RESULTS. The 30-day mortality rate was 3.2%, and 19% died during the ensuing 68-month interval. At 1, 24, and 60 months primary graft patency was 89%, 77%, and 74%, secondary graft patency was 91%, 80%, and 78%, and cumulative limb survival was 94%, 88%, and 84%, respectively. Cumulative patency rates at 60 months depending on outflow site were as follows: popliteal (85%), anterior tibial (80%), posterior tibial (70%), dorsal pedal (68%), and peroneal (60%). Patency at the peroneal position was significantly inferior to that of other infrapopliteal sites combined (p less than 0.05). Cumulative limb survival at 60 months, according to outflow site, was as follows: popliteal (95%), anterior tibial (85%), posterior tibial (78%), dorsal pedal (73%), and peroneal (67%). There was no significant difference in limb salvage among infrapopliteal outflow sites. However, patency rates and limb salvage were significantly better for the popliteal outflow site than the infrapopliteal outflow sites (p less than 0.01). CONCLUSIONS. (1) A 5-year graft patency rate of 78% and a limb salvage rate of 84% are achievable, (2) peroneal bypass is associated with a lower rate for graft patency but not limb salvage, and (3) popliteal bypass has the best graft patency and limb salvage rates.     

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.     

Revascularization of femoropopliteal artery occlusion in Werner's syndrome. Report of a case and review of surgical literature in cardiovascular lesions

A patient with Werner's syndrome suffering from a chronic ulcer on the right ankle joint underwent femoropopliteal bypass and patch angioplasty combined with endarterectomy of the distal popliteal artery. Postoperative angiography showed satisfactory graft patency and distal run-off, and the ulcer improved. Femoropopliteal occlusive disease in Werner's syndrome tends to have poor run-off and the internal diameter of the popliteal artery with diffuse arteriosclerotic lesion is often too small to facilitate distal anastomosis. Therefore, a conventional bypass procedure is not always effective and an aggressive attitude is essential to obtain sufficient ankle blood pressure and improve the leg ulcer in Werner' syndrome.     

Isolated popliteal arteries: results of surgical treatment and causes of failure

Isolated popliteal artery is defined as an obstruction of a superficial femoral artery with a patent popliteal segment followed by an obstructed distal popliteal artery or a patent leg artery less than 5 cm long. PURPOSE: The aim of this retrospective study was to report the results of surgical treatment and the causes of failures. PATIENTS AND METHODS: From 1988 to 1996, 31 patients with isolated popliteal artery were operated on with femoropopliteal bypass. The age of the patients ranged from 45 to 92 years, (mean: 79 years); all had critical ischemia that threatened limb viability. All underwent preoperative arteriography and diagnosis was confirmed by intraoperative arteriography. RESULTS: In the postoperative course, there were 22 patent bypasses (68%) with minor amputation in five patients, and nine thromboses that required a major amputation in seven patients, a trans-metatarsal amputation in one, and a medical treatment in one. With a mean 37-month follow-up, seven thromboses required a major amputation in five patients, a new bypass in one and a medical treatment in one. The death rate was 34% at two years. The actuarial patency rates of the bypasses were 51% at one year, 38% at two years and 25% at five years. The limb salvage rate was identical. The patency rates were 65% at one, two and five years for venous bypasses and 38%, 13% and 0% respectively for PTFE bypasses. Statistical analysis showed two causes of failure: the absence of a run-off branch and the use of PTFE prostheses. No other statistically significant cause of failure was demonstrated among those analysed. Favourable anatomic conditions for a bypass to a leg artery were not predictive of failure of a femoro-popliteal bypass on the isolated arterial segment. CONCLUSION: Bypass to isolated popliteal artery is indicated in patients whose limb viability is jeopardized. Results may be considered as satisfactory especially if there is a run-off branch and if a venous graft is available for the bypass.