Autogenous Vein Bypass Grafts Research Articles

Pharmacologic modulation of intimal hyperplasia in canine vein interposition grafts

Purpose: The purpose of this study was to evaluate the efficacy of three drugs (cilazapril, cyclosporine, and aspirin) in modulating the progression of intimal hyperplasia during short postoperative times in short-segment, autogenous vein bypass grafts in a canine model. The relative effects of the drugs on the progression of intimal hyperplasia were compared with the Gilman parameter, a measure used extensively as a wound healing descriptor. To our knowledge this is the first use of the Gilman parameter in assessing vascular disease.Methods: Seventy-two conditioned mongrel dogs were randomly and equally divided according to a three-factor analysis of variance. The factors included (1) drug treatments (cilazapril [10 mg/kg/day], cyclosporine [4 mg/kg/day], aspirin [325 mg/day], and control [nonmedicated]), (2) implantation sites (femoral and carotid arteries), and (3) postoperative times of graft harvest (1, 3, and 6 weeks). Each dog had 2 cm segments of autogenous jugular vein interpositioned bilaterally into each of the paired carotid and femoral arteries. Quantitative data on luminal narrowing over time from intimal hyperplasia were compared from calculated Gilman parameters after image analysis of retrieved, histologically processed graft sections.Results: The observed variability in the data was attributed to drug treatments and time. At 1 week after operation the mean Gilman parameters did not differ significantly among the treatment groups in either midgraft or distal graft segments. At 3 weeks the mean Gilman parameters of midgraft and distal graft sections of cyclosporine-treated dogs differed significantly (p < 0.05) from those of the control group and the cilazapril and aspirin-treated groups, which did not differ from each other. At 6 weeks after operation, mean Gilman parameters from aspirin- and cyclosporine-treated dogs differed statistically from control and cilazapril-medicated dogs and from each other (p < 0.001).Conclusions: These data support the efficacy of aspirin and cyclosporine in reducing intimal hyperplasia in short-segment arterialized vein grafts during short postoperative periods. Additional studies are required to ascertain whether the beneficial effects of aspirin and cyclosporine persist long-term.

Protection from atherosclerosis in vein grafts by a rigid external support.

Atherosclerosis is a common feature of autogenous vein bypass grafts resulting in their long-term failure. Arterial pressure-induced distension is thought to play a major role in the wall thickening of vein grafts, which may in turn favor atherosclerotic complications. In this study, we evaluated the influence of vein distension on the development of atherosclerotic lesions in jugular vein grafts interposed into the common carotid arteries of rabbits. The proximal half of each vein graft was wrapped with a 4-mm-diameter polytetrafluoroethylene graft that reduced the vein graft diameter by 46 +/- 5%. Fourteen animals were fed a 1% cholesterol-rich diet for 8 weeks, and five animals were fed a normal diet. In normocholesterolemic and hypercholesterolemic animals, the wall thickness and the total cross-sectional area were significantly reduced in wrapped compared with unwrapped segments. Foam cells were never observed in normocholesterolemic animals. In hypercholesterolemic rabbits, the sudanophilic lesions covered 62 +/- 4% of the luminal surface in unwrapped segments and 31 +/- 7% in wrapped segments (p < 0.0001). In transverse sections, the surface areas of foam cells were also markedly reduced in wrapped compared with unwrapped segments. Reduction of the wall distension using a rigid external support protected the vein grafts from atherosclerosis, possibly as a result of the decrease in wall thickening that occurred in response to arterialization.

Preventive effect of nicardipine on hyperplastic changes in venous bypass grafts.

Nicardipine is a relatively new calcium channel blocker with important properties that could result in attenuation of the adverse proliferative changes in autogenous vein bypass grafts. In this experimental, randomized, controlled study, the effect of nicardipine on the pathologic findings in aortoaortic bypass graft was assessed. Forty-two male rabbits (Orycytolagus cuniculus) were randomized to three groups: group 1 received nicardipine and groups 2 and 3 placebo for 4 weeks, after which an aortaortic bypass was realized with an autogenous inferior vena cava segment. During the following 4 weeks, groups 1 and 2 received nicardipine, and placebo was continued in group 3. The animals were sacrificed at the end of the study to permit removal and evaluation of the bypass grafts. The mean intimal and medial thickness values for groups 1 and 2 were lower than those for group 3, indicating that nicardipine has a significant preventive effect on the hyperplastic changes in venous bypass grafts compared to placebo. The mean intimal and medial thickness values of group 1 were also lower than those of group 2, and the differences carried statistical relevance, suggesting that the use of nicardipine before grafting could potentiate its protective effect. To provide stimulus for further research, an attempt is made to relate the hyperplasia-preventing effect of nicardipine to possible mechanisms.

Autogenous vein graft repair of injured extremity arteries: Early and late results with 134 consecutive patients

Autogenous vein tissue is recognized as the preferred material for extremity revascularizations that require the use of a conduit. However, the results after vascular repair of injured extremity arteries with autogenous vein interposition or bypass grafts have not been well defined. This study was done to determine both the early and late patency and limb salvage rates as well as the graft infection rate of autogenous vein repairs of injured extremity arteries. The records of 134 consecutive patients with acute extremity arterial injuries requiring repair with a reversed autogenous vein graft over a recent 5-year period were reviewed. Follow-up graft patency was defined by the presence of a palpable pulse and an extremity Doppler-derived pressure index of ≥ 0.9 distal to the arterial repair. Cumulative patency was assessed by the life-table method. Acute graft thrombosis occurred in two patients, one of whom underwent successful graft thrombectomy. Four patients (3%) required extremity amputation: one patient with a thrombosed vein graft and three patients with patent vein grafts but nonsalvageable limbs as a result of myonecrosis (2) or osteomyelitis (1). No perioperative graft infections occurred. One hundred twenty-eight patients (97%) had an intact extremity and a patent vein graft at the time of hospital discharge. One hundred three patients (80%) were examined at 30 days, and all grafts were patent. Seventy-three patients (57%) were available for follow-up at intervals exceeding 6 months, and 40 patients (31%) were followed-up for periods exceeding 24 months. All grafts were patent at late follow-up, resulting in a cumulative primary patency rate of 98% and a cumulative secondary patency rate of 99%. No late amputations were required. Autogenous vein grafts for the reconstruction of acute extremity arterial injuries provide excellent initial and long-term patency and durability as well as resistance to infection.

Long-term results with the above-knee popliteal expanded polytetrafluoroethylene graft

Since approximately 30% to 40% of autogenous vein bypass grafts to the femoropopliteal level may occlude within 5 years of implantation, additional vein will be required for subsequent revisions. We undertook a study to determine whether the preferential use of an above-knee expanded polytetrafluoroethylene bypass graft to save vein is an appropriate option. We reviewed our experience with 114 above-knee expanded polytetrafluoroethylene bypass reconstructions. Life-table analysis of primary and secondary graft patency was carried out by the method of Peto and statistically analyzed for the influence of clinical indication, runoff as determined by both preoperative and intraoperative completion arteriography, smoking, and diabetes. The 5-year primary patency rate of 57% for patients with claudication was comparable to contemporary randomized or retrospective series with below-knee autogenous vein for that indication, and it was superior to the patency rate for limb salvage. The status of the runoff vessels was an important determinant of outcome. The 59 limbs with good arteriographic runoff (2 to 3 vessels) had a markedly higher 5-year patency rate (70%) than the poor arteriographic runoff (0 to 1 vessels) group (30%). Continued cigarette smoking and diabetes mellitus also appeared to affect adversely primary graft patency in our hands. Our data support the use of preferential above-knee expanded polytetrafluoroethylene grafts in patients with good angiographic runoff. This approach does not appear to prejudice the limb against secondary revisionary procedures or the use of a new autogenous graft, if required.

Treatment of failed lower extremity bypass grafts with new autogenous vein bypass grafting

Treatment of failed lower extremity bypass grafts with new autogenous vein bypass grafting

Treatment of failed lower extremity bypass grafts with new autogenous vein bypass grafting

During the last 9 years we performed 111 bypass procedures for lower extremity ischemia, which occurred after failed infrainguinal bypass grafting. An all autogenous reversed vein bypass was achieved in 103 of 111 operations (93%). Five-year primary and secondary patency of bypasses placed as treatment for one or more failed prior bypass(es) was 57% and 71%, respectively, as compared to 80% and 83%, respectively, for 5-year primary and secondary patency of simultaneously placed first time leg bypasses. Five-year limb salvage for bypass procedures performed as treatment for failed bypass was 90%, which was identical to that achieved for first time bypasses.

下肢血行再建術における自家静脈グラフトと代用血管グラフトの手術成績の比較

下肢血行再建術における自家静脈グラフトと代用血管グラフトの手術成績の比較

Management of Recurrent Superior Vena Caval Syndrome with an Externally Supported Femoral Vein Bypass Graft

Management of superior vena caval syndrome with an autogenous vein bypass graft can be complicated by occlusion of the bypass graft. The case of a patient with recurrent superior vena caval syndrome due to occlusion of a spiraled saphenous vein graft who was managed with a femoral vein graft supported externally by a sleeve of ringed polytetrafluoroethylene is presented. A venogram demonstrated patency of the graft 11 months postoperatively, and the patient remains free from clinically apparent superior vena caval obstruction 18 months postoperatively.

SURGICAL MANAGEMENT OF ARTERIOSCLEROTIC BILATERAL FEMORAL AND RIGHT POPLITEAL ANEURYSMS

Multiple peripheral arterial aneurysms have been considered a relatively rare disease. A case is reported of a 70-year old man whose chief complaint was spontaneous pain in the right calf. Preoperative diagnosis by angiography and echography suggested bilateral common femoral and right popliteal aneurysms.The bilateral common femoral arterial aneurysms were treated by excision and Cooley double velour prosthetic interposition for resected aneurysms. In addition, the right popliteal arterial aneurysm was treated by the use of autogenous saphenous vein bypass grafting from above the aneurysm to below, with ligation of the aneurysm to prevent further embolization. Pathological examination indicated atherosclerotic aneurysm. The patient has been well for more than four years after surgery.Elective surgery is considered appropriate in the management of multiple peripheral arterial aneurysms when the surgical risk is reasonable, because of the high morbidity associated with femoral and popliteal arterial aneurysms.

Postoperative Pseudomonas urinary tract infections as a source of bacterial contamination of an autogenous vein graft

The infection of autogenous vascular grafts from blood-borne contaminants is distinctly unusual. Two cases are reported in which a urinary tract infection caused by Pseudomonas aeruginosa occurred after autogenous saphenous vein bypass grafting. Despite appropriate intravenous antibiotic therapy for 10 days with clearing of both blood and urine, the patients subsequently had significant complications from graft infections. The factors thought to have contributed to this are discussed and the literature reviewed. Recommendations are made concerning the modification of the standard therapy in this situation.

Flow- and pressure-adapted portal arterialization in dogs.

The effects of portal arterialization after portacaval shunt were studied in dogs. Flow- and pressure-adapted portal arterialization was performed by mounting a Teflon cuff on an autogenous vein bypass graft between the hepatic stump of the portal vein and the right renal artery. Immediately following operation, the total hepatic blood flow and intrahepatic portal venous pressure were within normal range. Eight weeks after operation, the intrahepatic portal venous pressure remained within the preoperative range, while total hepatic blood flow had increased double or triple. However, structural change due to increased flow was absent in the liver, even sixteen months after operation. Body weight, liver enzyme chemistry, ICG clearance rate, and amino acid metabolism were well maintained for the entire period of investigation. These findings suggest that sequelae such as hepatic encephalopathy and impaired hepatic metabolism after portacaval shunt can be avoided by portal arterialization, in the presence of an appropriate flow and pressure.

B-10 非逆転遊離自家静脈バイパスグラフトの長期遠隔成績と問題点について

B-10 非逆転遊離自家静脈バイパスグラフトの長期遠隔成績と問題点について

Vein graft angioplasty with nonballoon catheters.

Percutaneous transluminal angioplasty that was performed in five patients who had autogenous vein bypass graft stenosis using 6-French to 10-French teflon catheters was initially successful in all patients. One graft was patent at the time of death 15 months after angioplasty. In two patients grafts are patent 14 months and 13 months, respectively, after dilatation. One stenosis recurred at four months and again at eight months and was redilated on both occasions. Graft occlusion occurred at 11 months, and although it was redilated and lysed with streptokinase, the patient required an operation during which he died. One graft occluded at two months. No complications occurred from the angioplasties.

Treatment of Vein Graft Stenosis by Balloon Catheter Dilation

Percutaneous balloon catheter dilation was used to treate 12 high-grade stenoses in ten autogenous vein bypass grafts since September 1978. Four lesions occurred in femoropopliteal grafts, seven in femorotibal grafts, seven in femorotibial grafts, and one in an axillofemoral graft. Balloon catheter dilation was successful and surgery avoided in 11 of the 12 lesions. Pedal pulses were restored in eight of the ten patients, and the pulse in a femorotibial bypass graft was improved in another. Postdilation arteriography demonstrated a substantial increase in luminal diameter, and ankle pressure indexes were improved in all successful cases. The tenth had an operative correction of the stenosis. There were no complications with the procedure. Percutaneous balloon catheter dilation appears to be an effective method of treating stenosis in autogenous vein grafts and a useful alternative to surgical revision.

Vein bypass to the tibial, peroneal and dorsalis pedis arteries for limb ischaemia.

Fifty-nine autogenous vein bypass grafts were performed to the distal leg arteries in 57 patients for limb salvage over a 10 year period.Analysis of results by the Life Table showed a cumulative patency of 74% at 1 month and 59% patency at 6 years. Failure of the vein graft in the early post-operative period resulted in amputation, and in almost 50% of cases, at an aboveknee level. Of 18 patients whose grafts thrombosed, 16 required major amputation, and infection in another 6 patients with patent grafts resulted in limb loss. With these exceptions, all the patients with patent grafts had viable and functional limbs. Of 37 diabetic patients subjected to operation, 17 lost their limbs during follow-up. There was no significant difference in patency of grafts inserted proximally or distally into the tibial vessels. The hospital mortality was 8% and one-fourth of patients subjected to operation died of causes related to atherosclerosis during follow-up.Reduction of the early post-operative failure rate by careful patient selection and meticulous operative technique makes arterial bypass operations to the distal tibial vessels beneficial to many patients who are otherwise doomed to amputation.

Sympathetic blockade and reversed saphenous vein by-pass grafting: an experimental study.

The value of sympathetic blockade as an adjunct to femoropopliteal arterial reconstruction is disputed. The effect of lumbar sympathectomy and of pharmacological adrenergic blockade with intraarterial reserpine on the patency of experimental autogenous vein by-pass grafts was evaluated. Thirty-one grafts by-passing a chronic superficial femoral artery occlusion were inserted in adult mongrel dogs. The mean graft flow was reduced by a distal stenosis, below a known critical level of 60 ml per minute. In 10 grafts, no further procedure was done. These grafts occluded. In 11 grafts, an ipsilateral lumbar sympathectomy was done. Near normal flow was restored in 9 and these remained patent. No flow increase was achieved in 2 and these failed. In a further 10 grafts, 0.5 mg of reserpine was injected intra-arterially. In 9 of these grafts, near normal blood flow was restored and these remained patent. In one graft, no flow increase was achieved, and the graft failed. The role of sympathetic blockade in reconstructive surgery is discussed. It is concluded that a trial of intra-arterial reserpine in femoropopliteal arterial surgery is warranted.

Chronic mesenteric arterial insufficiency: results of revascularization in 33 cases.

The symptoms of mesenteric arterial insufficiency and the advantages of surgical revascularization have become widely recognized in recent years. Follow-up data are accumulating on patients who have had surgery for revascularization. In this study we report on 33 patients who had mesenteric revascularization for intestinal angina. Twenty-nine patients presented with postprandial pain; most had weight loss. Abdominal bruits were heard preoperatively in 26 patients. Aortogram demonstrated involvement of one mesenteric vessel in 13 (39%) patients and two or more vessels in 20 (61%). Revascularization was accomplished with the use of a Dacron graft or an autogenous vein bypass graft to 48 vessels. Endarterectomy and patch angioplasty were done once. One patient died in the early postoperative period. Of the other 32 patients, 30 (94%) had relief of symptoms. Eight patients died from 8 to 135 months after operation, but only one died from mesenteric vascular occlusion and bowel infarction. Five years after operation, 83% of the patients were alive; in ten years, 62%.

Tibial and Peroneal Bypass in Severe Occlusive Disease of the Lower Extremities

Symptomatic arteriosclerotic occlusive disease involving the femoral and proximal popliteal arteries is currently best treated by reversed autogenous saphenous vein bypass graft. Severe occlusive disease frequently includes the popliteal and/or origin of the trifurcation vessels with reconstitution of one or more of the vessels in the lower leg. We have used distal bypass 97 times in 90 patients during the past decade. There was only one postoperative death in the series in spite of the advanced age and concurrent disease in the majority of the patients. Our indications for operation continue to be relief of pain or salvage of an extremity. We rely on high quality preoperative angiograms for selection of vessels to receive the bypass. The posterior tibial artery was used in 63 of the cases, while the anterior tibial and peroneal were used in 24 and 10 cases, respectively. There were 11 immediate inhospital failures in this series of 97 cases requiring amputation in five. Three additional patients had amputations during the ensuing several months. Of the 85 grafts functioning at the time of discharge from the hospital, 16 or (18.8%) failed during the first years. Grafts that remained patent for one year have a high incidence of long term patency which is in keeping with other reported series.

Bypass vein grafts in patients with distal popliteal artery occlusion

The results obtained by placing reversed autogenous saphenous vein bypass grafts in either isolated popliteal artery segments or tibial vessels distal to the popliteal artery are compared. Fifty-five patients with arteriosclerotic peripheral vascular disease who were threatened with limb loss were followed up from six months to nine years prior to this report. The success rate at one year was 94 per cent for the isolated popliteal segment grafts and 73 per cent for the tibial vessel grafts. The success rate after four years was 70 per cent for the isolated popliteal segment grafts and 63 per cent for the tibial vessel grafts. The clinical factors associated with the success of isolated popliteal segment bypass grafts and the factors apparently associated with failure of vein grafts in both of these groups with very poor distal arterial outflow are discussed. Our results suggest that either an isolated popliteal artery segment graft or a tibial vessel graft is a satisfactory means of treating these patients; however, a graft to an isolated popliteal segment is probably preferable to a graft to a tibial artery.