Below-knee Femoropopliteal Bypass Research Articles

Early results of endovascular treatment using percutaneous vacuum-assisted thromboaspiration in acute lower limb ischemia

Introduction. Open balloon thrombectomy and embolectomy remain the preferred initial option in the management of acute lower limb ischemia (ALI), but various endovascular techniques have become accessible and are growing in popularity. The aim of the study was to assess our early experience with percutaneous vacuum-assisted thromboaspiration using the Penumbra/Indigo® system for non-traumatic ALI. Material and methods. The study group comprised 13 patients with ALI who received treatment between September 2022 and June 2023; with 7 (53.8%) being males. The median age was 71 years (25%-75%IQR 62.5-77.5). ALI cases were classified according to the Rutherford scale: grade I – 2 (15.3%), grade IIA – 7 (53.8%), and grade IIB – 4 (30.7%). In 10 (76.9%) cases, ischemia was classified as “acute-on-chronic.” The occluded native vascular segment, determined through preoperative computer tomography angiography (n=4; 30.7%), duplex scanning (n=5; 38.4%), or both examinations (n=4; 30.7%), were as follows: superficial femoral artery (n=7) and popliteal artery (n=2). In two patients, thrombosis of the below-knee femoropopliteal bypass with autogenous vein was identified, while two others presented with femoral artery stent thrombosis. An embolic etiology of ALI was observed in 4 (30.7%) cases, and thrombotic etiology in 9 (69.2%) cases. Endovascular access was established via the ipsilateral common femoral artery (n=10), crossover (n=2), or brachial artery (n=1). Thromboaspiration was carried out using dedicated CAT6™ and CAT8™ catheters. Results. The technical success rate of vacuum-assisted thromboaspiration was 92.3%. Subsequent angiography revealed accompanying occlusive-stenotic lesions in all instances, necessitating transluminal angioplasty, and in 8 (61.5%) patients, additional stenting was required. Catheter-directed thrombolysis was utilized as an adjunct in one patient. There were 2 (15.3%) instances of distal embolization, both addressed within the same surgical session. Survival and limb salvage rates at the 30th-day follow-up stood at 100%. Conclusions. Utilizing the Penumbra/Indigo® system, percutaneous vacuum-assisted thromboaspiration appears to be a safe and effective minimally invasive technique for treating ALI. This method allows for the concurrent correction of coexisting chronic peripheral arterial lesions.

Changes in deep femoral artery topography during open revascularization of the lower limbs

To study topographic changes of femoral triangle arteries during open revascularization of the lower limbs. A retrospective study included 30 men aged 59.6±3 years with atherosclerotic femoropopliteal occlusion and chronic lower limb ischemia IIb-III stage according to the Pokrovsky-Fontaine classification. All patients underwent open reconstructive interventions. Ten patients underwent above-knee femoropopliteal replacement with a synthetic prosthesis, 10 patients - above-knee femoropopliteal bypass with a synthetic prosthesis, 7 patients - above-knee femoropopliteal bypass with autologous vein, 3 patients - below-knee femoropopliteal bypass with autologous vein. Control group consisted of 30 healthy mean aged 60±2 years. Ultrasound was carried out using the Esaote My Lab Alfa scanner (3-12 MHz linear transducer and 3-5 MHz convex transducer). In healthy volunteers, deep femoral artery always arose from common femoral artery under the angle ≤30° in all cases (20° - 93.3% of cases, 30° - 6.7% of cases). In patients with previous surgical treatment, angle of deep femoral artery varied from 35 to 80°. After femoropopliteal bypass grafting with autologous vein, angle of deep femoral artery varied from 35 to 45° (35° - 8 patients, 40° - 1 patient, 45° - 1 patient). After femoropopliteal bypass grafting with a synthetic prosthesis, angle of deep femoral artery increased up to 40-50° (40° - 2 patients, 50° - 8 patients). In case of previous femoropopliteal replacement with a synthetic prosthesis, angle of deep femoral artery increased up to 70-80° (70° - 7 patients, 75° - 2 patients, 80° - 1 patient). Normally, angle of deep femoral artery does not exceed 30°. Open reconstructive surgery on femoropopliteal arteries increases this value from 30° to 80°. Minimal changes are observed after femoropopliteal bypass grafting with autologous vein.

Autologous saphenous vein and heparin-bonded expanded polytetrafluoroethylene as graft materials for below-the-knee femoro-popliteal bypass in patients with critical limb ischemia: A propensity score-matched analysis

ObjectiveTo compare the outcomes of heparin bonded expanded polytetrafluoroethylene (HePTFE) and autologous saphenous vein (ASV) in patients undergoing below-knee (BK) femoro-popliteal bypass for critical limb ischemia (CLI). DesignRetrospective single-centre matched case–control study. MethodsFrom 2003 to 2019, 275 consecutive BK bypasses for CLI were performed, 109 with the ASV and 166 with a HePTFE graft. All the baseline characteristics that were reliably measured and were potentially relevant in the decision-making process were included as confounders in a logistic regression model and the factors that were significantly different between the two groups then used to perform a propensity matching analysis. Propensity score-based matching was performed in a 1:1 ratio to compare outcomes. Arterial hypertension, hyperlipemia, the need for tibial anastomosis at the distal level and the run-off status were the covariates included in the matching. Follow-up outcomes were estimated by Kaplan–Meier methods and compared with log rank test. ResultsAfter propensity matching, 101 HePTFE bypasses were matched with 101 ASV bypasses. The median duration of follow-up was 37 months (range 1–192). The 5-year survival rate was 67.5% (standard error (SE) 0.05) in the HePTFe group and 64.5% (SE 0.06) in the ASV group (p = 0.8, log rank 0.04). Primary patency rates were 38% (SE 0.06) in the HePTFE group and 41% (SE 0.06) in the ASV group (p = 0.7, log rank 0.3). Also assisted primary patency and secondary patency rates did not differ in the two groups. Amputation-free survival was 53% (SE 0.05) in the HePTFE group and 58% (SE 0.06) in the ASF group (p = 0.6, log rank 0.2). ConclusionsHePTFE provided 5-year similar results to those obtained with use of the ASV in equivalent patients with CLI undergoing below-knee or tibial bypass.

Long-term outcomes of Omniflow II biosynthetic vascular graft in lower extremity arterial revascularization.

This study aims to evaluate the patency rates and long-term outcomes of femoro-popliteal bypass procedures with Omniflow II biosynthetic vascular grafts in patients with occlusive vascular disease. This retrospective, observational, clinical study included a total of 93 patients (61 males, 32 females; mean age 56.9±7.4 years; range, 43 to 83 years) who underwent femoro-popliteal bypass in which Omniflow II biosynthetic vascular grafts were used due to peripheral arterial disease. The patients were divided into two groups: 62 patients undergoing femoro-popliteal above-knee bypass and 31 patients undergoing the femoro-popliteal belowknee bypass. We evaluated preoperative clinical characteristics, postoperative graft patency rates, and other clinical results. The mean follow-up was 44.9±18.8 months in the femoropopliteal above-knee bypass group and 47.3±22.3 months in the femoro-popliteal below-knee bypass group (p=0.302). The cumulative primary graft patency rates of the femoro-popliteal above-knee bypass and femoro-popliteal below-knee bypass groups at three, four, and five years were 98%, 95% and 78% and 86%, 75% and 45%, respectively (log-rank; p=0.312). The cumulative assisted graft patency rates of the femoro-popliteal above-knee bypass and femoro-popliteal below-knee bypass groups at five years were 87.9% and 65.3%, respectively (log-rank; p=0.530). The Omniflow II biosynthetic vascular graft is suitable for above- and below-knee femoro-popliteal bypass procedures. These grafts may be prefered due to high patency rates, low incidence of aneursym formations, and infections.

Retrospective Evaluation of the First 150 Patients with Vascular Surgery in A New Cardiovascular Surgery Clinic

Objective: This study aimed to retrospectively evaluate the data of patients undergoing peripheral arterial vascular surgeries and to present our approach to peripheral arterial disease (PAD) in our clinic, which was put into service as of September 2014. Methods: Data on 151 patients undergoing peripheral arterial vascular surgery between September 2014-December 2016 were retrospectively evaluated. Of the patients, 45 (29.80%) underwent emergency surgery and 106 (70.19%) underwent elective surgery. Of emergency surgeries, 31 (68.88%) patients had acute embolism. Among elective surgeries, femoropopliteal bypass was the most common procedure in 52 patients. While above-knee femoropopliteal bypass was performed in 40 (76.92%) patients, vena saphena magna (VSM) could be used as a graft in 31 patients. VSM could be used in 9 of 12 patients undergoing below-knee femoropopliteal bypass. Results: Of 151 patients, 14 (9.27%) were admitted for revision during the postoperative period. Among 52 patients undergoing femoropopliteal bypass, 7 were re-operated (4 underwent above-knee and 3 underwent below-knee femoropopliteal bypass). While the polytetrafluoroethylene graft was used in all of these patients, none of the patients with VSM graft required revision. The patient with Shamblin type-III tumor, who was operated due to glomus caroticum, developed graft occlusion and was re-operated; however, hemiplegia was developed postoperatively. Mortality occurred in 4 patients (2 with abdominal aortic aneurysm rupture and 2 with penetrating injury). All of them had hypovolemic shock prior to the surgery. Conclusion: There is a need for an experienced team for PAD and the treatment method to be applied should be patient-based.

Graft type for femoro-popliteal bypass surgery.

Graft type for femoro-popliteal bypass surgery.

IP229 Proposal of a Multicentric-Based Score for Graft Patency in Below-knee Femoropopliteal Bypass With Heparin-Bonded ePTFE Graft in Patients With Critical Limb Ischemia

IP229 Proposal of a Multicentric-Based Score for Graft Patency in Below-knee Femoropopliteal Bypass With Heparin-Bonded ePTFE Graft in Patients With Critical Limb Ischemia

Heparin-bonded expanded polytetrafluoroethylene femoropopliteal bypass grafts outperform expanded polytetrafluoroethylene grafts without heparin in a long-term comparison

Expanded polytetrafluoroethylene (ePTFE) grafts have become an acceptable prosthetic alternative to autologous vein for infrainguinal arterial reconstructions. Recently, heparin bonding to the graft's luminal surface has been used as an adjunctive method of improving graft patency. We retrospectively evaluated a prospective experience with heparin-bonded ePTFE (HePTFE) vs the results of a prior experience with standard ePTFE (SePTFE) to compare patency rates in above-knee (AK) and below-knee (BK) femoropopliteal bypass through the 5-year follow-up. Prosthetic femoropopliteal bypasses performed by our four-surgeon group were constructed using 6-mm SePTFE grafts before August 2007. Subsequently, all such bypasses were constructed using 6-mm HePTFE (Propaten graft; W. L. Gore & Associates, Flagstaff, Ariz). The surgical technique used in all cases throughout the study was similar irrespective of surgeon or graft material. Loss of primary patency was defined by graft thrombosis; duplex scan confirmed graft failure. Descriptive estimation of patency rates was carried out using standard Kaplan-Meier methods. Cox proportional hazards regression was used to analyze relationships between predictors and time to loss of patency. There were 192 AK (87 Propaten, 105 SePTFE) and 60 BK (42 Propaten, 18 SePTFE) grafts. Overall primary patency for Propaten was statistically better than SePTFE at years 1 (93.6% vs 84.2%), 2 (79.7% vs 73.8%), 3 (79.7% vs 69.5%), 4 (74.5% vs 59.9%) and 5 (74.5% vs 56.2%; log-rank test, P= .036). Five-year primary patency was superior for Propaten AK grafts (85.2% vs 59.3%; log-rank test, P= .028) and for Propaten BK grafts (59.6% vs 0.0/undeterminable; log-rank test, P= .016). Variables significantly associated with loss of patency for Propaten and SePTFE were claudication (hazard ratio [HR], 0.41), age (HR, 0.95), isolated popliteal artery (HR, 3.1-4.4), and ankle-brachial index after the procedure (HR, 0.10). Controlling for conduit effect, clopidogrel use did not significantly affect patency (P= .076). No grafts were associated with heparin-induced thrombocytopenia. These data show that the Propaten HePTFE graft offered significantly better long-term patency over the SePTFE graft, suggesting Propaten as the prosthetic graft of choice for bypasses to the femoropopliteal artery when autologous vein is unavailable or inappropriate.

Morbidity of femoropopliteal bypass surgery

A systemic review of published reports on the incidence of early (<30 days) adverse events occurring after above- or below-knee femoropopliteal bypass surgery was conducted to provide contemporary outcomes data for comparative reporting. A total of 38 articles were included describing 6,374 femoropopliteal bypasses in 6,007 patients. Fifty-two percent were male and the mean age was 64.6 years (range, 40 to 93 years). The various studied types of complications were reported in 10 to 34 of 38 articles and definitions were often missing. The overall 30-day morbidity rate was 36.8%. The wound infection rate was 7.8% (range, 0.0 to 17.4%) accompanied with dermal necrosis in 0.4%. Graft infection was described in 2.4% (range, 0.0 to 5.3%) of cases. Postoperative bleeding was seen in 7.4% (range, 0.0 to 26%), of which 2.5% required return to surgery. Occlusions were reported in 12.0% (range, 0.0 to 59%). Lymphedema occurred in 2.9% (range, 0.0 to 9.6%) of cases and surgical site seroma formation occurred in 2.0% (range, 1.0% to 3.0%). Overall 30-day mortality rate was 2.3% (range 0.0 to 4.3%). Pooled data comparing vein grafts and prosthetic grafts revealed no significant difference (P = .10; risk ratio = 0.82; 95% confidence interval, 0.66−1.03; I2 = 0%) in the incidence of complications. This review confirmed the morbidity of femoropopliteal bypass surgery is inconsistently reported and definitions are lacking. Because one-third of patients can be expected to experience an adverse event after femoropopliteal bypass grafting, standards on defining and reporting complications are necessary if comparative outcome standards are developed.

Analysis of risk factors for occlusions of a synthetic femoropopliteal bypass graft.

Femoropopliteal bypass is a revascularization technique of lower extremities with excellent outcome. The great saphenous vein is the best graft material, but if it is not adequate or has been removed, synthetic grafts are an useful alternative. Graft occlusion is the most significant complication with the most serious consequences. The aim of this study was to analyse predictive factors for the synthetic femoropopliteal bypass occlusions. This retrospective case-control study included all patients who underwent synthetic femoropopliteal bypass due to peripheral arterial occlusive disease at the Vascular Surgery Center, Clinical Center of Kragujevac, Serbia, from 2007 to 2013. The cases group were the patients with femoropopliteal graft occlusion (n = 44), with the control group consisted of the patients without such an outcome (n = 88). Significant effects to occlusion were: concomitant cardiovascular disease (adjustedOR 27.05; 95% CI 4.74; 154.35), a type of femoropopliteal bypass (adjustedOR 16.50; 95% CI 4.05; 67.24), previous vascular intervention (adjustedOR 4.67; 95% CI 1.20; 18.14), clinical stage of the disease (adjustedOR 3.73; 95% CI 1.94; 7.18), administration of postoperative oral anticoagulant therapy (adjustedOR 0.05; 95% CI 0.01; 0.23) and the use of angiotensin converting enzyme inhibitors (adjustedOR 0.14; 95% CI 0.03; 0.70). A significant synergism was shown for the following combinations of the observed risk factors: type of femoropopliteal bypass and cardiovascular disease, type of femoropopliteal bypass and previous vascular intervention, previous vascular intervention and cardiovascular disease, previous vascular intervention and beta blockers, cardiovascular disease and diabetes, type of femoropopliteal bypass and antiaggregant therapy, clinical stage of disease and cardiovascular disease, previous vascular intervention and antiaggregant therapy. Concomitant cardiovascular disease, below-knee femoropopliteal bypass, advanced stage of vascular disease and non-use of anticoagulant therapy and angiotensin-converting enzyme inhibitors are the significant predictors of graft occlusion after synthetic femoropopliteal bypass. Their synergistic effect determines the importance of diabetes, use of beta blockers and platelet antiaggregant therapy.

Ruptura – Apresentação invulgar de aneurisma popliteu

Popliteal aneurysms are the most common peripheral aneurysms, but its rupture is a rare complication with a risk of limb loss and mortality.The authors present a case report of a 66-year-old patient with a sudden onset of pain and hematoma on the distal thigh and popliteal fossa, anemia, foot drop and limb edema from rupture of a large popliteal aneurysm (7cm).Ecodoppler evaluation was the only preoperative imaging investigation, which provided suitable information for diagnosis and urgent surgical planning. The operation consisted on a below-knee femoropopliteal bypass with great saphenous vein graft following aneurysm exclusion. At 3-month follow-up the patient is asymptomatic and the reconstruction is patent without complications.Vascular intervention is mandatory for bleeding control, revascularization and compartment decompression.

The deep veins in arterial reconstructive surgery for limb salvage in patients with multiple occlusions of the femoral and tibioperoneal vessels

Below-knee femoropopliteal and femorodistal bypass with nonautologous material shows poor patency rates, especially in multiple occlusions of the tibioperoneal vessels. Twenty-four patients underwent arterial reconstruction for limb salvage using the deep leg veins because the great saphenous vein was not available owing to previous operations. A follow-up period of forty-two months revealed an average bypass patency rate of 75%. During the control period all patients were prospectively investigated concerning changes in the venous system. The authors found only little changes in the venous system and no significant signs of venous insufficiency. The deep leg veins seem to be a valuable addition to arterial reconstructive surgery for limb salvage.

Usefulness of PTFE Graft in Above-Knee Femoropopliteal Artery Bypass

Purpose: Which graft material is appropriate for the above-knee femoropopliteal (AK fem-pop) bypass has been a controversy. We were to evaluate the usefulness of PTFE graft in AK fem-pop bypass by comparing the results of autogenous vein graft in below-knee femoropopliteal bypass. Methods: This was a retrospective study of data for Fem-Pop bypass from August 1999 to August 2008. The median follow-up was 59.9±27.3 months. The demographic data, patency rate, secondary procedures, and amputation rate were compared, and statistical comparison was performed by Kaplan-Meier method, Log-rank test, and Chi-square test. Results: Seventy-three bypasses were performed in 63 patients: PTFE graft in 48 cases (Group A), autogenous vein in 25 cases (Group B). Sixty-one patients (96.81%) were men. The mean age was 67.3±8.0 years. The indication for surgery was intermittent claudication in 27 cases (37.0%), critical limb in 46 cases (63.0%). The 6-yr primary patency rates were 28.1%; 60.3%, the 6-yr secondary patency rates were 37.2±8.4%, 67.0±14.7% in Group A and Group B, respectively (P＜0.05). The number of secondary procedures was 31 and 3, respectively (P＜0.05). Major amputation at later periods was not needed in Group B, but there were 9 cases in group A (P＜0.05). Conclusion: PTFE graft for above-knee femoropopliteal bypass shows poor long-term patency with a large number of secondary procedures and a higher amputation rate than vein graft in BK Fem-Pop bypass. PTFE graft should be limited to patients with high operative risk, or poor venous graft.

Long term outcome of femoropopliteal bypass for claudication and critical ischemia.

We performed 167 femoropopliteal bypass surgeries in 151 patients (95 patients underwent above-knee bypass and 56 below-knee bypass) from December 1985 to December 2000 with the use of prosthetic graft or autologous vein graft. We compared primary patency rates between age, sex, graft material, distal anastomotic site and severity of ischemia, considering their survival rates to elucidate the long-term outcome of above-knee and below-knee femoropopliteal bypass. The 10 year patency rate for above-knee bypass was 47.4%, compared to 36.9% for below-knee ( p < 0.01). Better results were found after bypass surgery for claudicants than for critical ischemia ( p < 0.05). With regard to graft material and age categories, there were unexpectedly no statistical differences in either above-knee or below-knee anastomosis. The survival rate at 10 years in claudicants was 51.2%, compared to 15.9% with critical ischemia ( p < 0.01). Mortality was much influenced by ischemic heart disease ( p < 0.002) and the age of patient ( p < 0.05). The results after above-knee bypass had comparable patency, whereas the results after below-knee bypass were disappointing. Below-knee arterial reconstruction for claudicants should be carefully considered and might be recommended only to patients with critical ischemia.

Prospective Randomized Study of Carbon-Impregnated Polytetrafluoroethylene Grafts for Below-Knee Popliteal and Distal Bypass: Results at 2 Years

The purpose of this prospective randomized multicenter study is to compare patency for a new carbon-impregnated polytetrafluoroethylene (PTFE) graft and standard PTFE grafts. One hundred and sixty patients presenting severe chronic ischemia of the lower extremity were recruited at 17 centers of the French Association Universitaire de Recherche en Chirurgie. Eighty-one carbon-impregnated graft and 79 standard grafts were implanted. The procedure consisted of below-knee femoropopliteal bypass in 83 cases and femorodistal bypass in 77 cases. The minimum duration of the follow-up period was 2 years. Twenty-four patients died during the study. The actuarial primary patency rate, actuarial secondary patency rate, and limb salvage rate were 45%, 53%, and 57% respectively in the carbon-impregnated PTFE group and 35%, 36%, and 47% respectively in the standard PTFE group. The carbon-impregnated graft appeared to achieve better patency than the standard graft but the difference was not statistically significant. Since there was no difference up to 12 months, the study will be continued to determine if further follow-up confirms these findings. In this study we also assessed factors contributing to patency of below-knee prosthetic bypass grafts. Only two factors had a significant influence on patency, i.e., ankle/arm pressure difference greater than 0.25 as opposed to ankle/arm pressure difference less than 0.25 (p < 0.01) and below-knee femoropopliteal bypass as opposed to femorodistal bypass (p < 0.001).

The performance of femoropopliteal bypasses using polytetrafluoroethylene above the knee versus autogenous vein below the knee

Controversy exists as to the choice of conduit for the treatment of superficial femoral artery occlusive disease, particularly when a patent above-knee popliteal artery exists. Some surgeons advocate the preferential use of polytetrafluoroethylene (PTFE), whereas others favor the use of autogenous vein. This report compares our experience with above-knee femoropopliteal bypass with PTFE versus below-knee femoropopliteal bypass with autogenous vein. This study covers a 15-year period extending from 1982 to 1996 during which 1,313 arterial reconstructions were performed for superficial femoral and/or proximal popliteal arterial disease. Four hundred and thirty-eight procedures were performed to the above-knee popliteal artery using PTFE, and 875 procedures were performed to the below-knee popliteal artery using autogenous vein. The indication for surgery was limb salvage in 77% of patients in the PTFE group and 88% of patients in the vein group. The 1-, 3-, and 5-year cumulative life table primary patency rates for the PTFE group were 74%, 56%, and 50%, respectively. The primary patency rates for the vein bypass group were 83%, 75%, and 67%, respectively (P < 0.01). The 5-year cumulative limb salvage rates were 91% and 95% for the PTFE and vein groups, respectively (P = NS). In this series, below-knee femoropopliteal venous reconstructions have superior patency rates compared with above-knee femoropopliteal PTFE reconstructions. Venous reconstruction for femoropopliteal occlusive disease gives the optimal long-term result. Prosthetic reconstruction should be considered for patients with limited venous conduit or decreased life expectancy.

The deep veins in arterial reconstructive surgery for limb salvage in patients with multiple occlusions of the femoral and tibioperoneal vessels

Below-knee femoropopliteal and femorodistal bypass with nonautologous material shows poor patency rates, especially in multiple occlusions of the tibioperoneal vessels. Twenty-four patients underwent arterial reconstruction for limb salvage using the deep leg veins because the great saphenous vein was not available owing to previous operations. A follow-up period of forty-two months revealed an average bypass patency rate of 75%. During the control period all patients were prospectively investigated concerning changes in the venous system. The authors found only little changes in the venous system and no significant signs of venous insufficiency. The deep leg veins seem to be a valuable addition to arterial reconstructive surgery for limb salvage.

Below-knee Femoropopliteal Bypass Using Externally Supported Polytetrafluoroethylene (PTFE) Grafts

Twenty-seven externally supported polytetrafluoroethylene (PTFE) grafts were implanted in the femoropopliteal position crossing the knee joint. All patients underwent surgery because of limb threatening ischemia (rest pain or gangrene). There was one early graft failure (successful thrombectomy). No patient died postoperatively. The mean follow-up period was 17.32 months (range 3-44 months). Cumulative patency rate for this follow-up period was 73%. Absence of kinking when bending the knee joint was determined by ankle Doppler pressure measurements and arteriography. If an adequate saphenous vein is not available for knee-crossing femoropopliteal bypass, externally supported PTFE can be used, yielding short-term patency rates comparable to those obtained with autologous venous bypasses.

Four years' results of a prospective, randomized clinical trial comparing polytetrafluoroethylene and modified human umbilical vein for below-knee femoropopliteal bypass

Polytetrafluoroethylene (PTFE) (Gore-Tex) and human umbilical vein (Biograft) arterial grafts were compared for below-knee femoropopliteal bypass grafting in a prospective randomized clinical trial. One hundred five patients (105 limbs) entered the trial. Seventy-six percent suffered from rest pain, ulceration, or gangrene. The median postoperative ankle-arm blood pressure index was 0.36. Twenty-three limbs had three patent tibial arteries, 46 limbs had two tibial arteries, 31 limbs had one patent artery, and five limbs had isolated popliteal segments. Thirty-four percent were repeat operations. Fifty-five patients were allocated to receive PTFE grafts and 50 to receive human umbilical vein grafts. The two groups were comparable as to preoperative risk factors and operative and postoperative treatment. During the first 4 years (maximum 1609 days) 40 PTFE graft and 24 umbilical veins occluded. At 1 year the PTFE patency rate was 53% and at 4 years was 22%. For umbilical vein the corresponding figures were 74% and 42% (p = 0.005, Gehan test). During follow-up the incidence of PTFE failure was on the average 2.1 times higher than that of umbilical vein failure (95% confidence limits 1.2 to 3.4).

Four years' results of a prospective, randomized clinical trial comparing polytetrafluoroethylene and modified human umbilical vein for below-knee femoropopliteal bypass

Polytetrafluoroethylene (PTFE) (Gore-Tex) and human umbilical vein (Biograft) arterial grafts were compared for below-knee femoropopliteal bypass grafting in a prospective randomized clinical trial. One hundred five patients (105 limbs) entered the trial. Seventy-six percent suffered from rest pain, ulceration, or gangrene. The median postoperative ankle-arm blood pressure index was 0.36. Twenty-three limbs had three patent tibial arteries, 46 limbs had two tibial arteries, 31 limbs had one patent artery, and five limbs had isolated popliteal segments. Thirty-four percent were repeat operations. Fifty-five patients were allocated to receive PTFE grafts and 50 to receive human umbilical vein grafts. The two groups were comparable as to preoperative risk factors and operative and postoperative treatment. During the first 4 years (maximum 1609 days) 40 PTFE grafts and 24 umbilical veins occluded. At 1 year the PTFE patency rate was 53% and at 4 years was 22%. For umbilical vein the corresponding figures were 74% and 42% (p = 0.005, Gehan test). During follow-up the incidence of PTFE failure was on the average 2.1 times higher than that of umbilical vein failure (95% confidence limits 1.2 to 3.4).