Long term results of 66 femoral-to-femoral by-pass grafts: a 9-year follow-up

Over an 8-year period, 66 femoral-to-femoral grafts were performed for unilateral iliac artery disease. The grafts were inserted retropubically with an operative mortality of 4.5 per cent. The minimum follow-up has been 12 months and cumulative patency 80 per cent at 6 years. Sixteen patients had critical ischaemia (preoperative Doppler ankle pressure less than 40 mmHg) and 50 patients had severe ischaemia (preoperative ankle pressure greater than 40 mmHg). The graft significantly improved initial ankle pressures and this improvement was maintained at late follow-up (average 45 months). There was no evidence of a detrimental effect on the donor limb. Long term patency was adversely affected if there was preoperative critical ischaemia, a woven Dacron prosthesis was used or the patient continued to smoke.     

Is arterial reconstruction to the ankle worthwhile in the absence of autologous vein?

Autologous vein from either the arm or the leg is the preferred conduit for femoro-crural grafting. Limb salvage rates using prosthetic grafts have been sufficiently disappointing for many surgeons to consider primary amputation in the absence of suitable vein. We have attempted to improve prosthetic graft patency by the creation of a compliant, wide diameter vein collar at the distal anastomosis. Thirty patients with critical ischaemia (i.e.: rest pain with distal tissue loss or doppler ankle pressure less than 40 mmHg2.3) have undergone grafting to a crural vessel in the lower third of the calf using 6 mm externally supported PTFE (IMPRA) with a vein collar (17% of all lower calf grafts, 9% of all femoro-distal procedures). Five of the grafts occluded in the peri-operative period, resulting in major amputations. Another 4 grafts occluded within 12 months of operation resulting in amputation. A further 7 grafts have occluded but not required amputation. Fourteen (47%) grafts remain patent at a mean follow-up of 13.9 months (range 1-49) with a mean graft patency of 10 months. The aim of salvage surgery is to maintain independence until death supervenes. In this series 6 (20%) patients have died during follow-up and the best possible result in the 30 patients would have been a total of 417 "amputation avoided" months. In fact 300 "amputation avoided" months were achieved. Moreover, 21 legs (70%) have avoided amputation during the patient's lifetime, or at the most recent follow-up. These results suggest that femorocrural grafting using PTFE with a vein collar is worthwhile and preferable to primary amputation in the elderly patient.     

Popliteal artery puncture in the assessment of patients with severe leg ischemia.

Two-plane angiography and direct segmental pressure measurements in the femoral and popliteal arteries and indirectly on the arm and ankle were performed in 101 limbs seeking to establish a relationship between angiographic assessment of the patency of the popliteal artery and the trifurcation vessels and the popliteal ankle pressure difference. When the tiberoperoneal trunk or the trifurcation vessels were occluded or more than 50% of the lumen was stenosed, the pressure difference exceeded 10 mmHg in 30/40 limbs (75%). When three, two, or only one of the tibial vessels were patent, the pressure difference exceeded 10 mmHg in 2/58 limbs (3%). One month following above knee femoropopliteal bypass (48 limbs), patients with a popliteal-ankle difference less than 10 mmHg obtained a significantly higher ankle pressure index (PI 0.86, range 0.56-1.20) (p less than 0.01) than those with a pressure difference exceeding 10 mmHg (PI 0.66, range 0.40-0.91). The clinical state 6 months following femoropopliteal bypass did not demonstrate that patients with a low popliteal-ankle difference fared better than patients with a higher pressure difference; however, the PI appeared significantly lower in the latter group compared to the former. The graft material was correlated to the popliteal-ankle pressure difference. It appeared that prosthetic grafts failed within 6 months when the difference exceeded 10 mmHg in 10/12 limbs (83%), but autologous vein grafts only failed in 2/10 limbs (20%). Finally, it was possible to predict the postoperative ankle pressure index significantly from data derived from the pressure measurements.     

Distal femoropopliteal bypass using a composite graft of PTFE and non-reversed saphenous vein

The results of femoropopliteal bypass to the infragenicular popliteal artery, in the absence of suitable saphenous vein have, in the main, been disappointing. We present a new type of composite graft, for use when the distal anastomosis is below the knee, which avoids the potential problems of prosthetic graft alone. The graft consists of a proximal segment of 6 mm expanded PTFE (Gore-Tex; or Impra), anastomosed to transposed non-reversed autologous saphenous vein. Forty-two patients were studied following unilateral, below knee composite femoropopliteal graft surgery for severe claudication or critical ischaemia. Pressure indices were calculated along with intraoperative flow rate, and all patients were followed up at regular intervals to assess graft patency. During the study period three patients died and graft occlusion occurred in a further eight. Analysis of the cumulative patency curve revealed that the majority of occlusions occurred in the first 3 months. The patency at 12 and 18 months was encouraging with values of 84% and 79% respectively. Comparison of pressure indices revealed a significant increase following surgery (P less than 0.001). The postoperative pressure index appeared to predict the grafts likely to occlude and the intraoperative flow rates mirrored a similar trend. Grafts which occluded had a significantly lower pressure index and flow rate (P less than 0.01, P less than 0.002, respectively). Our results suggest that for infragenicular femoropopliteal bypass grafting where full length in-situ vein graft is not possible; a composite graft using PTFE with non-reversed vein is a good alternative.     

Delayed distal blood pressure rise after partial arterial reconstruction for combined aorto-iliac and superficial femoral artery occlusive disease

The blood pressure in the ankle and great toe was measured with cuff and strain-gauge technique in 39 patients after insertion of aorto-femoral bifurcation graft. In 40 limbs with patent superficial femoral artery (complete reconstruction) the distal blood pressure remained unchanged from the tenth postoperative day to follow-up after 12 to 26 months. In 30 limbs with occluded superficial femoral artery (partial reconstruction) the ankle/arm pressure index rose from 0.54 to 0.61 between the tenth day and late follow-up. The blood pressure in the great toe had increased by 8 mmHg on the tenth postoperative day and by additionally 17 mmHg during the next 12 to 26 months. The delayed pressure rise after partial arterial reconstruction presumably reflected development of collateral vessels from the deep femoral artery system. The clinical significance of the findings is discussed.     

Popliteal-to-distal bypass grafts for critical leg ischaemia

BACKGROUND: To assess the value of revascularization to crural and pedal arteries using the popliteal artery as inflow source. METHODS: Experimental design: Retrospective study with a mean follow-up period of 15.2 months (range, 0-46). Setting: Academic referral center. Patients: 62 patients with critical leg ischaemia and popliteal artery suitable as inflow source for infrapopliteal arterial revascularisation. Interventions: 66 popliteal-to-distal bypass procedures, of which 18 popliteal-crural bypass grafts and 48 popliteal-pedal bypass grafts. Main outcome measures: Bypass graft patency, leg salvage, survival and success defined as patients alive with leg. RESULTS: At 1-month, 1-year, and 2-year follow-up, the primary patency rates were 87%, 58%, and 55%, secondary patency rates were 95%, 70%, and 67%, leg salvage rates were 97%, 88%, and 88%, while 88%, 70%, and 66% of patients were alive with legs at the same intervals. At 2-year follow-up the survival rate was 72%. Above-knee popliteal-to-distal bypasses achieved better primary patency (p=0.02) and corrected primary patency rates (p=0.01) than below-knee popliteal-to-distal bypasses. Diabetes and uraemia affected the survival and patients alive with leg rates. CONCLUSIONS: Popliteal-to-distal bypass surgery is worthwhile for the management of severe, isolated infrapopliteal atherosclerotic disease. Diabetic and uraemic patients are at high risk for both leg and life loss after revascularisation. Grafts originating from the above-knee popliteal artery may achieve better patency rates than those originating from the below-knee popliteal artery.     

Preliminary results with endoluminal femoropopliteal thrupass

BACKGROUND AND AIMS: Results of endovascular procedures to the superficial femoral artery and popliteal artery are not as good as at the iliac level. The purpose of this study is to evaluate the long-term results of a new endoluminal stent-graft for the management of lesions of the femoropopliteal segment. MATERIAL AND METHODS: Fifteen patients underwent endoluminal treatment of femoropopliteal lesions with a PTFE covered stent-graft. Nine patients had critical leg ischaemia, two patients had acute leg ischaemia, two patients were claudicants, one patient had a ruptured popliteal artery aneurysm, and one had a large adjuvant therapeutic arteriovenous fistula. RESULTS: The procedure was successfully carried out in all patients. Thrombosis occurred in two stent-grafts 4.5 months and 12.5 months after the procedure. One of them was successfully thrombolysed. During the two-year follow-up, a haemodynamically significant decrease in ankle/brachial index was observed in two patients. Ankle/brachial index was the same or higher than the immediately postoperative value in six patients. Primary patency rates at 1 month, 1 year and 2 year follow-up were 100%, 93% and 84%, respectively. Assisted primary patency rates at the same intervals were 100%, 93% and 93%, respectively. No patient had limb loss during the follow-up period. CONCLUSIONS: Endoluminal femoropopliteal bypass using PTFE covered stent-graft can be successfully performed with good two-year results.     

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.     

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.     

DUPLEX SCAN SURVEILLANCE OF INFRA-INGUINAL BYPASS GRAFTS: THE CASE FOR SELECTIVITY

A consecutive series of 270 non-reversed infra-inguinal saphenous vein bypass grafts performed by the same surgeon between January 1986 and January 1991 was reviewed. The series included 250 in situ and 20 translocated non-reversed grafts. The aims were to calculate the number of duplex scans that would have been required for surveillance, to determine the value of a non-selective prolonged scanning regimen and to identify subgroups requiring more (or less) intensive surveillance. Indications were for critical ischaemia in 194 patients, popliteal aneurysms in seven patients and incapacitating claudication in 69 patients. Patients were reviewed at 1 month and then at approximate 6 month intervals for symptoms and with resting and post-exercise ankle pressures. Primary patency of grafts placed to a popliteal distal anastomosis for critical ischaemia was 85% (s.e.m. 9.1%) at 3 years while secondary patency was 94% (s.e.m. 8.1%) at 4 years. Primary patency of grafts placed to a tibial artery or isolated popliteal segment was 68% (s.e.m. 8.4%) at 2 years while secondary patency was 76% (s.e.m. 9.9%) at 2.5 years. The difference in secondary patency between popliteal and tibial grafts was highly significant (P= 0.003). Tibial grafts required significantly more secondary early intervention than popliteal grafts. If recommended protocols for serial duplex scan (DS) surveillance had been followed, a minimum of 960 scans would have been required. If the tibial bypass group only had been monitored, 702 of these scans would have been avoided with a maximum loss of one popliteal graft and no limbs. This study suggests that non-selective DS surveillance in ambulant asymptomatic patients with a popliteal distal anastomosis may not be justified. Both early and intensive surveillance of tibial grafts appear justified.     

Duplex scan surveillance of infra-inguinal bypass grafts: the case for selectivity.

A consecutive series of 270 non-reversed infra-inguinal saphenous vein bypass grafts performed by the same surgeon between January 1986 and January 1991 was reviewed. The series included 250 in situ and 20 translocated non-reversed grafts. The aims were to calculate the number of duplex scans that would have been required for surveillance, to determine the value of a non-selective prolonged scanning regimen and to identify subgroups requiring more (or less) intensive surveillance. Indications were for critical ischaemia in 194 patients, popliteal aneurysms in seven patients and incapacitating claudication in 69 patients. Patients were reviewed at 1 month and then at approximate 6 month intervals for symptoms and with resting and post-exercise ankle pressures. Primary patency of grafts placed to a popliteal distal anastomosis for critical ischaemia was 85% (s.e.m. 9.1%) at 3 years while secondary patency was 94% (s.e.m. 8.1%) at 4 years. Primary patency of grafts placed to a tibial artery or isolated popliteal segment was 68% (s.e.m. 8.4%) at 2 years while secondary patency was 76% (s.e.m. 9.9%) at 2.5 years. The difference in secondary patency between popliteal and tibial grafts was highly significant (P = 0.003). Tibial grafts required significantly more secondary early intervention than popliteal grafts. If recommended protocols for serial duplex scan (DS) surveillance had been followed, a minimum of 960 scans would have been required. If the tibial bypass group only had been monitored, 702 of these scans would have been avoided with a maximum loss of one popliteal graft and no limbs.(ABSTRACT TRUNCATED AT 250 WORDS)     

Intra-operative haemodynamic findings and their prognostic significance in femoropopliteal reversed saphenous vein graft bypass operations.

Post-reconstructive graft blood flow (basal flow') was measured by means of an electromagnetic flowmeter in 72 consecutive femoropopliteal reversed saphenous vein grafts performed for occlusive atherosclerosis causing leg ischaemia. In the last 48 operations, post-reconstructive pre- and post-graft intra-arterial pressures were recorded, and graft blood flow after papavarine-induced vasodilation ('maximal flow') was measured. Mean 'basal flow' was 132 ml/min, mean 'maximal flow' 285 ml/min and mean flow increment after papavarin 136%. Mean 'basal flow', mean 'maximal flow' and mean flow increment after papavarine were higher in the claudication group than in the gangrene group, and higher in cases having good angiographic run-off than in those having poor. Mean common femoral and popliteal pressures were 85 and 80 mmHg, with no differences between different groups. Mean post-reconstructive graft pressure gradient was 5.1 mm. Mean peripheral resistance was 769 milliprus, being higher in the gangrene group and in cases having poor run-off. The prognostic significance of these findings was evaluated by analysing patency in all patients living 3 months ('early') and 1 year ('late') after operation. Cases having a 'basal flow' less than 60 ml/min, a 'maximal flow' less than 200 ml/min or a flow increment after papavarine less than 100% had significantly poorer 'early' patency (p less than 0.01) and 'late' patency (p less than 0.05). Femoral and popliteal pressures, graft pressure gradients and peripheral resistance did not influence patency significantly.     

Relationship of femorodistal bypass patency to clinical outcome. Iloprost Bypass International Study Group.

OBJECTIVE: To investigate the relationship between bypass patency, limb survival and clinical symptoms after femorodistal bypass procedures. DESIGN: Multicentre, prospectively planned 12-month postoperative follow-up. PATIENTS AND METHODS: Five hundred and seventeen patients undergoing femorodistal bypass surgery for severe ischaemia. Clinical symptoms, bypass patency were recorded at regular intervals up to 12 months postoperatively. RESULTS: Complete follow-up data was obtained on 498 patients (96%). Fifty-six (17%) of the 341 patients with patent bypasses had either rest pain or ulcers or had undergone major amputation at 12 months. Of the 167 patients with an occluded bypass, 22 patients (13%) had improved clinical symptoms and a total of 59 patients (35%) had avoided major amputation at 12 months. The clinical outcome for patients classified preoperatively as Fontaine stage IV was significantly worse than for those in stage III preoperatively despite similar bypass patency rates. CONCLUSIONS: There is a fair correlation between technical and clinical outcome after femorodistal bypass surgery at 12 months, but there are significant numbers of patients with occluded bypasses who have a good clinical outcome and of patients with patent bypasses who have a poor clinical outcome. The reporting of symptoms in addition to bypass patency would aid the interpretation of surgical results.     

Femoro-femoral arterial bypass is an effective and durable treatment for symptomatic unilateral iliac artery occlusion

AIMS: This study was designed to determine the effectiveness of femoro-femoral arterial bypass (FFB) operation at hospital discharge and 1 year after operation, and to determine the role of long saphenous vein (LSV) as a conduit. METHODS AND RESULTS: A retrospective review was undertaken of 161 consecutive patients (median age, 66 years; range, 44-97 years) who had femoro-femoral grafts during the 12 years from July 1987 to March 1999. The indication for operation was claudication in 66 patients and critical ischaemia in 95. A synthetic graft was used in 123 patients and LSV in 38. Six patients with LSV had a previously infected synthetic graft and 2 a previously occluded synthetic graft. In-hospital operative mortality was 13 (8.1%). One year postoperatively, known mortality was 29, fifteen patients were lost to follow-up putting 1-year mortality at 18.0-27.3%. Eight of these had LSV as the conduit. At discharge from hospital, the median improvement in the ankle brachial pressure index was 0.3 (range, 0-1.0) overall, and 0.32 for patients with LSV (range 0-1.0). Among the 117 known survivors at 1 year, secondary graft patency was 107 confirmed by Doppler or duplex (91.5%) overall, and 25 (89.3%) for LSV; 100 (85.5%) maintained symptomatic improvement, 11 (9.4%) were experiencing no benefit and 6 (5.1%) were worse, of whom 2 had undergone amputation. In patients in whom LSV was used, 22 (78.8%) remained symptomatically improved, 3 (10.7%) experienced no benefit, 3 deteriorated and one had an amputation. CONCLUSIONS: One year following FFB, at least 18.0% of patients were dead. Among possible survivors to 1-year, graft patency was at least 78.8% and at least 75.8% remained clinically improved. FFB is effective in the treatment of unilateral iliac artery occlusion. LSV is as effective as a synthetic conduit.     

Comparison of infrainguinal graft surveillance techniques

One hundred seventy-seven patients with infrainguinal bypass grafts were followed by use of standard graft surveillance techniques to learn more about the natural history of hemodynamic abnormalities in the patient with no symptoms. A decrease in the ankle/brachial pressure ratio of 10% or more was considered an abnormal evaluation. Results of the duplex scan were interpreted as abnormal when the peak systolic flow velocity was greater than 120 cm/sec or less than 40 cm/sec. There were 18 graft thromboses (10%) during the period of observation, and nine of these grafts were successfully revised or replaced. Recurrent symptoms prompted graft revision in 20 additional patients, and 18 of these reoperations were successful. Twenty-nine of the 38 reoperations occurred within the first 18 months of the study. The primary cumulative patency rate was 86% at 1 year and 66% at 5 years. The secondary cumulative patency rate was 91% at 1 year and 80% at 5 years. Sudden graft occlusion occurred in five patients after a normal ankle/brachial index. Most of 90 patients with abnormal ankle/brachial indexes reverted to normal at the next visit. Nineteen of the 26 that did not, had significant graft problems, but only eight patients had operable conditions, and five of the eight already had occluded grafts. No patient with a normal ankle/brachial index and duplex scan results had graft occlusion before their next surveillance visit. If the duplex scan outcome was abnormal but the ankle/branchial index normal the incidence of sudden graft occlusion was 4%. In contrast, if the duplex scan outcome was abnormal and the ankle/brachial index is reduced, then the risk of graft occlusion is 66%.(ABSTRACT TRUNCATED AT 250 WORDS)     

Dual function of the distal arteriovenous fistula for maintenance of arterial and venous prosthetic graft patency in the lower extremity

Venous hypertension, severe swelling, and tissue necrosis occurred in a limb previously subjected to distal arterial bypass plus adjunctive arteriovenous fistula. Occlusion of the popliteal vein had not been recognized during the early treatment period. Subsequent to identification of this mechanism, limb salvage was achieved with an interposition graft of the popliteal vein using externally supported PTFE. The prereconstruction venous pressure gradient of 29 cm H2O was virtually abolished immediately after reestablishing venous outflow. The distal arteriovenous fistula, initially established to maintain prosthetic arterial graft patency, now serves, in this case, a dual function by additionally maintaining prosthetic venous graft patency. An intact deep venous system is critical for achieving successful arterial reconstruction and to avoid the complications associated with an occluded outflow tract in the face of augmented inflow.     

The distribution of atherosclerosis in the lower limbs.

Sixty-seven consecutive aortograms in non-diabetic patients were studied to establish the distribution of atherosclerosis in the arteries of 134 lower limbs. Prolonged filming and multiple exposures of the feet showed ankle vessels in 131 of the limbs (98%) and a pedal arch or collaterals in 126 (93%). In 51% of the limbs at least one of the calf arteries was occluded and only 24% had two patent arteries at ankle level. The pedal arch was complete in only 16%. The patency rate of the pedal arch was similar in all three symptom groups (p greater than 0.05). Two separate analyses were performed. The first was based on symptoms. Critical ischaemia was present in 18 limbs (13%), claudication in 69 limbs (52%) and 47 limbs were symptomless (35%). The second analysis was based on the sites of major occlusion. Occlusions were already present in 81% of the symptomless limbs, predominantly in the distal vessels. In limbs with claudication or critical ischaemia there were more occlusions above the knee (77 and 89%, respectively) than in limbs without symptoms (36%) (chi 2 = 27.60, p less than 0.001). Occlusion of the popliteal artery was significantly more frequent in the patients with symptoms of critical ischaemia (50%) than in either of the other two groups (chi 2 = 15.61, p less than 0.001). Atherosclerosis appears to develop in the small vessels of the calf and foot at an early stage. The extent of this involvement may influence the progression of symptoms and the outcome of treatment.(ABSTRACT TRUNCATED AT 250 WORDS)     

Percutaneous transluminal angioplasty of iliac and femoral arteries in severe lower-limb ischaemia

Percutaneous transluminal angioplasty was performed 92 times in 86 patients with severe lower-limb ischaemia (40% occlusion), giving rise to rest pain and/or gangrene. The patients were thereafter observed for periods up to 5 years. Criteria for success were appearance of normal groin pulse (iliac angioplasty) or persistent greater than or equal to 0.15 rise in arm/ankle blood pressure index (femoropopliteal angioplasty). The respective technical success rates were 82% and 64%. The complication rate was 10.9%, including 5.4% distal embolization. Patency rates were higher in iliac than in femoropopliteal lesions, in stenotic than occluded vessels, and also when the lesion was shorter than 5 cm and if there was good run-off. Limb salvage exceeded patency by 10% in the iliac procedures and by 15% in the femoropopliteal. Percutaneous transluminal angioplasty is recommended for selected cases of severe lower-limb ischaemia, and should always be considered for limb salvage. Reocclusion does not necessarily imply clinical failure. Technical failures should be included in calculated patency rates in order to document the method's limitations.     

The effect of vein diameter on patency of in situ grafts

In an attempt to evaluate the effect of vein diameter on early patency and long-term durability of in situ lower limb bypasses, we evaluated 195 femoral-distal, popliteal, and/or tibial bypasses constructed in 189 patients (153 men, 36 women), consisting of tibial bypasses in 116 (60%), and popliteal in 79 (40%). The operative angiograms were reviewed and the vein diameter was measured to the nearest 0.5 mm. Postoperative follow-up consisted of visits every three months where graft patency was assessed by physical examination and measurement of graft flow velocity and ankle-brachial indices. Conduits less than 3 mm had a higher rate of occlusion in the 0-30 day interval, but following that period performed satisfactorily. No conduit less than 2 mm was successfully utilized, because of inability to incise valves without injury in these tiny conduits. Following the perioperative period, conduit diameter does not affect the long-term durability of in situ bypass grafts.     

Extraperitoneal unilateral iliac artery bypass for chronic lower limb ischaemia

Extraperitoneal unilateral iliac artery bypass was used to treat chronic lower limb ischaemia in 105 patients (110 operations). This represented 20% of all operations for aorto-iliac disease. Unilateral iliac bypass was the preferred primary procedure for 99 operations, and was used to correct complications in one limb of a prior aortic bifurcation graft in the other 11. Ipsilateral femoropopliteal vein grafts were also performed in 45 legs (43%), prior to the iliac bypass in 18, as a synchronous operation in nine, and at a later date in 18 legs. This was a much higher proportion of combined operations than for patients by aortic bifurcation grafts (12%). Only 5 patients later required further proximal surgery, one for a blocked graft and four for contralateral iliac disease. The cumulative patency rate in surviving patients was 91% at 3 years. For the claudicants and for iliofemoral bypass operations, only one graft occluded, within 5 years, and no grafts occluded for operations where the superficial femoral artery was patent. The cumulative patency rates at 3 years were 85% for patients with critical ischaemia, 82% for ilioprofunda bypass operations, and 88% for operations where the superficial femoral artery was occluded. The cumulative foot-salvage rate in surviving patients initially treated for critical ischaemia was 77% at 3 years. The cumulative survival rate was 90% at 3 years. Extraperitoneal unilateral iliac bypass is now preferred as the primary operation for patients with apparent unilateral iliac disease causing severe ischaemia, if balloon dilatation is not appropriate or has failed.