Outcome of ProCol, a Bovine Mesenteric Vein Graft, in Infrainguinal Reconstruction

OBJECTIVES: historically infrainguinal reconstruction using heterogenous grafts has given poor results due to degradation and aneurysmal dilatation of the graft. A recently introduced heterogenous graft, the ProCol (bovine mesenteric vein) graft, may yield improved results. There are no published reports with respect to ProCol in infrainguinal reconstruction and hence we have reviewed our initial experience with this graft. METHODS: retrospective analysis of six patients in whom infrainguinal reconstruction with ProCol was undertaken between March and August 2001. RESULTS: the primary patency rate was 0% at 3 months, with grafts failing between 4 and 113 days. Two grafts underwent aneurysmal dilatation.Conclusion: we are unable to recommend use of the ProCol graft in infrainguinal reconstruction.     

Systematic review of preservation methods and clinical outcome of infrainguinal vascular allografts

OBJECTIVE: We systematically reviewed clinical studies on the use of venous and arterial allografts for infrainguinal revascularization. We attempted to find evidence for the best infrainguinal vascular allograft by a systematic review of the available literature. METHODS: An electronic search of the MEDLINE, EMBASE, and Cochrane databases was used to determine key articles from studies on the different types of vascular allografts used in infrainguinal reconstruction from 1966 to 2004. Articles were independently reviewed by using previously defined inclusion and exclusion criteria. Study results were gathered with cumulative primary patency as the primary end point. Secondary end points were major complications, graft disintegration, and major limb loss. Quantitative analysis was performed on the prospective randomized trials, and linear regression analysis was performed on cumulative primary patency. Fontaine's classification system was applied. RESULTS: No systematic review of randomized controlled trials was found. Five randomized controlled trials, 3 prospective cohort or case series, and 15 retrospective case series with 3,837 vascular allografts were found. Methods of allograft preservation were cryopreservation (5 studies), cold storage (3 studies), and glutaraldehyde preservation of human umbilical veins (15 studies). One-year cumulative primary patency rates were 13% to 79% for cryopreservation, 63% to 80% for cold storage, and 40% to 91% for glutaraldehyde. The weighted mean 1-year cumulative primary graft patency rate was 41% for cryopreservation, 71% for cold storage, and 70% for glutaraldehyde allografts. Four randomized trials on femoropopliteal bypasses demonstrated higher patency rates of glutaraldehyde-preserved human umbilical veins than polytetrafluoroethylene grafts. Statistical heterogeneity between studies (I(2) = 91.4%) was too high to perform a formal meta-analysis. The rate of major limb loss was 20% to 58% for cryopreservation, 10% to 69% for cold storage, and 0% to 65% for glutaraldehyde, and the percentage of graft disintegration was 2% to 6% for cryopreservation, 4% to 15% for cold storage, and 0% to 11% for glutaraldehyde. CONCLUSIONS: A firm conclusion could not be made because there were no studies available in which direct comparison was performed between different preservation methods of vascular allografts. In addition, heterogeneity of the individual studies hampered direct comparison of different types of vascular allografts. However, the overall graft performance of glutaraldehyde-preserved human umbilical vein allografts may be superior to that of other vascular allografts.     

Arterial grafts in coronary bypass surgery.

During the last three decades, coronary artery bypass grafting (CABG) emerged, was developed and has progressed. The search for suitable conduits has been investigated aggressively and several venous, arterial and artificial grafts have been utilized clinically. It is clear now that the saphenous vein graft deteriorates with time and the occlusion rate reaches up to 50% at 10 years after CABG mainly due to atherosclerosis in the graft called "vein graft disease." The internal thoracic artery (ITA) graft, on the contrary, has very good long-term patency and this evidence directly relates to the superior outcome in terms of longevity and postoperative cardiac events in the long run. Based on this evidence, the use of arterial conduits for myocardial revascularization has been extended. Several autologous arteries have been investigated and utilized clinically such as the right gastroepiploic artery, the inferior epigastric artery, and the radial artery. With proper use of these new arterial conduits in addition to ITA, higher quality CABG can be performed safely, and a better long-term result can be expected.     

Evaluation of patency of synthetic and autogenous venous and arterial micrografts in rats

Long-term patency rates of synthetic and autogenous venous and arterial microvascular grafts in rats were compared. The grafts were interposed between the carotid arteries. The geometry of the anastomoses was designed in a manner intended to be comparable to the situation commonly encountered in cerebral revascularization procedures in man. Patency rates were 37.5% for synthetic grafts, 90% for venous grafts, and 60% for arterial grafts. Venous grafts are the best currently available microvascular prostheses.     

An Animal Model for Small-Diameter Arterial Grafts

A rabbit model was developed to study small-diameter arterial grafts. A total of 158 2-mm-diameter polytetrafluoroethylene (PTFE) grafts und 35 autogenous carotid artery (AA) grafts were interposed in the carotid arteries of New Zealand white rabbits. A pilot study of 16 PTFE grafts used to develop operative and anesthetic techniques had a 20% mortality and 38% early (<2 day) thrombosis rate. Subsequent to the pilot study 177 grafts were placed and a 92% postoperative survival with 100% AA graft patency and 93% PTFE graft patency at 2 weeks was observed. AA grafts followed beyond 16 weeks continued to have 100% patency, while PTFE grafts began to show increased failure. Closure was found to be due to the development of anastomotic myointimal hyperplasia.     

Arterial reconstruction at diverse sites using nonreversed autogenous vein. An application of venous valvulotomy.

Improved instrumentation for venous valve extirpation has allowed rapid development of the in situ technique for femoral-tibial arterial reconstruction. Extension of this valvulotomy technique permits the expeditious construction of branched, nonreversed saphenous vein grafts for multiple vessel revascularization, and allows use of veins otherwise unsuitable in length for certain arterial bypass procedures. The nonreversed vein graft also appears to offer advantages over the reversed graft with regard to the size of the proximal and distal anastomoses when used as an aortorenal or iliorenal graft as well as in other anatomic locations. Over the past 30 months these techniques were used to implant 10 vein grafts at diverse sites in nine patients with initial success in all instances and one late graft failure.     

Late Results of Clinical Experience with Small Caliber Biological Grafts

Abstract: Small caliber biological grafts that were hepa-rinized and nonheparinized were implanted in 52 patients with arterial obstructive disease and chronic renal failure by either conventional suture anastomosis or laser anastomosis over the last 8 years. There were no operative mortalities. The overall postoperative patency rate was 91% at 1 year, 85% at 3 years, and 82% at 5 years. The heparinized graft anastomosed by laser clearly had the best results with a 100% patency rate at 5 years without pathological anastomotic intimal hyperplasia. Therefore, the heparinized biological graft anastomosed by laser could be the best option for the reconstruction of small vessels although these grafts might be clinically useful for small caliber grafts.     

The fate of the radial artery conduit in coronary artery bypass grafting surgery.

Coronary artery bypass grafting (CABG) is the standard surgical procedure for the treatment of advanced coronary artery disease. CABG surgery has been demonstrated to improve symptoms and, in specific subgroups of patients, to prolong life. Despite its success, the long-term outcome of coronary bypass surgery is strongly influenced by the fate of the vascular conduits used. Impressive long-term disease-free patency rate of the left internal thoracic artery-left anterior descending coronary artery (LITA-LAD) graft, coupled with proven long-term survival benefits, has led to its becoming a 'golden standard' of CABG. Previous long-term studies have also shown unsatisfactory patency of saphenous vein grafts used for myocardial revascularization, compared with internal thoracic artery grafts. Thus, the use of arterial conduits has expanded beyond the internal thoracic arteries (ITAs) to include the right gastroepiploic artery, the inferior epigastric artery, and the radial artery. The assumption is that although the performance of one or two arterial ITA graft is superb, more arterial grafts should perform better in the long-term follow-up. Several studies concerning the use of the radial artery bypass grafts have documented excellent clinical results and satisfactory short-term as well as mid-term patency rates at restudy angiography, supporting its continued use as a bypass conduit. However, a note of caution concerning radial artery conduit patency rate have appeared in few recent reports. Thus, in this paper, we summarize the current evidence about the radial artery as a conduit in CABG surgery, with special emphasis on the clinical results.     

Rat femoral vein-to-vein grafts as a microvascular practice model: factors that influence patency

The rat femoral vein has become a standard model for microvascular anastomosis practice as well as for research investigations into various manipulative influences upon venous patency. Although vein grafts to the rat artery are the focus of many experimental studies, few reports have investigated vein-to-vein grafts. This study examines the short-term patency (1-3 days) of vein grafts interpositioned to the rat femoral vein. Several factors are studied for their ability to alter the patency rate. The results indicate that patency is difficult to achieve following the creation of a second serial anastomosis (construction of a vein-to-vein graft). Systemic heparin consistently improves patency rates, and trends toward increased patency are seen for reduction in longitudinal tension of the repaired vessel. It is also implied that a deeper understanding of venous hemodynamics and thrombotic events may lead to improved methodologies in the clinical applications of microvenous repairs. These results indicate that rat vein-to-vein grafts may provide a challenging microvascular training model, while introducing the novice microsurgeon to some of the complicating factors encountered with microvascular grafting.     

Comparison of clinical outcomes of reconstruction of the anterior cruciate ligament: autogenous patellar tendon and hamstring grafts

In this critical review, we summarize the literature comparing the 2 grafts most frequently used in reconstruction of the anterior cruciate ligament--patellar tendon and hamstring autografts. We evaluate the biomechanical properties, comorbidities, and clinical performance of the grafts and focus our review on clinical outcomes reported in prospective randomized studies. Although the overall profile of the autogenous hamstring graft with respect to biomechanics and side effects seems equal or superior to that of the patellar tendon graft, there is little difference in clinical outcomes. From review of prospective randomized trials and a large controlled retrospective study, the trend suggests if fixation is controlled, outcomes are similar with the 2 grafts, with the possible exception of when they are used with high-demand athletes, in whom patellar tendon grafts may show a slight disadvantage. Large-scale prospective randomized studies with careful data collection and control are needed to better define graft performance in vivo.     

Internal thoracic artery: to skeletonize or not to skeletonize?

The internal thoracic artery has been the most reliable graft material used in coronary artery bypass grafting with an excellent long-term patency rate. Complete myocardial revascularization with internal thoracic arteries improves long-term survival and decreases the rate of repeat operations compared with vein grafts. Adequate length of the graft in coronary artery bypass graft surgery is essential for providing complete arterial revascularization. In the last decade or so, technique of skeletonization of internal thoracic artery has been proposed to achieve extra length. Skeletonization of the internal thoracic artery allows the preparation of longer conduits with a superior free flow and can reduce the incidence of postoperative pulmonary and sternal complications. However, concerns about vasoreactivity of skeletonized internal thoracic artery grafts, the functional consequences of surgical trauma, the possible loss of innervation, and vasa vasorum perfusion in the skeletonized conduits have prevented this technique from being universally accepted. Presently available evidence from retrospective studies (level 3 evidence) suggests that skeletonization is a safe and effective technique for myocardial revascularization. However, there is a need for conducting multicenter, randomized controlled trials comparing the skeletonized and pedicled internal thoracic arteries with special emphasis on long-term patency to conclusively validate the safety and efficacy of skeletonization technique.     

Arterial reconstruction of infected femoral artery pseudoaneurysms using superficial femoral-popliteal vein

BACKGROUND: Infected femoral artery pseudoaneurysms (IFAPs) secondary to percutaneous arterial access, injection of illegal substances, and from infected synthetic grafts, appear to be increasing in incidence. Ligation of IFAPs without revascularization offers control of infection but may risk limb ischemia. Revascularization with extraanatomic synthetic grafts may risk reinfection and abrupt thrombosis. Excision of IFAPs with revascularization using superficial femoral popliteal vein (SFPV) provides both control of infection and excellent limb perfusion. STUDY DESIGN: A retrospective review was conducted of patients diagnosed with IFAP who underwent resection and revascularization with SFPV at a single medical center. Outcomes measured included reinfection and amputation rate. These were compared with other series using various methods to treat IFAPs. RESULTS: Eleven patients with IFAP were encountered from 1992 to 2004. Mean age was 64 years (+/-10 SD). Five patients developed IFAP secondary to percutaneous arterial access procedures. Four patients developed infected femoral artery pseudoaneurysms secondary to synthetic graft infection. Two patients developed IFAP secondary to injection of illegal substances in the femoral region. All patients had positive wound cultures initially. Staphylococcus was the most common organism found in wound cultures. All patients underwent resection of IFAP with lower extremity revascularization using SFPV. There was no incidence of limb ischemia and no perioperative deaths in this series. CONCLUSIONS: Excision of IFAP with revascularization can be successfully achieved using SFPV. This method may prove to be superior to other methods with apparent higher patency rates and resistance to reinfection.     

Freshly harvested cadaveric venous homografts as arterial conduits in infected fields

Six patients with patent multilevel prosthetic grafts (three axillofemoral-femoral grafts, an aortobifemoral graft, an axillofemoral and femoral-anterior tibial graft, and an axillofemoral and femoral-popliteal graft) that demonstrated overt infection involving both the proximal inflow (one infrarenal aorta, five axillary arteries) and groin anastomoses required complete graft excision. Cadaveric inferior vena cava, common and external iliac, common and superficial femoral, and greater saphenous veins were harvested in conjunction with multiple organ donor procedures. Identical anatomic reconstruction within the infected fields was accomplished, with patency and distal perfusion maintained for intervals sufficient to achieve complete resolution of infection in all cases. This interval of revascularization with a venous homograft has served as a temporizing maneuver, which permitted eradication of infection and allowed subsequent reimplantation of prosthetic graft material without associated reinfection in the two instances in which it was required. Use of freshly harvested large-caliber caval, iliac, and femoral homograft veins as arterial substitutes in infected fields has not been previously reported. Case histories and a review of the venous homografting literature are included.     

Highly flexible nitinol mesh to encase aortocoronary saphenous vein grafts: first clinical experiences and angiographic results nine months postoperatively

Saphenous vein graft patency is frequently limited by degeneration. Experimental studies have indicated that rigid external support of venous grafts by a flexible, tubular nitinol mesh may improve graft patency. The study presented was part of a prospective, randomized, multicenter first-in-man trial investigating the safety and effectiveness of nitinol-supported venous grafts in coronary artery bypass graft (CABG) surgery. From our clinic, 25 subjects with multivessel coronary artery disease requiring saphenous vein graft CABG of the right coronary artery (RCA) and the circumflex artery were entered into the trial. Subjects were randomized to receive a mesh-supported graft on one of these arteries; the other vessel received an untreated vein graft. Graft patency was assessed by coronary angiography nine months after surgery. The implantation of mesh grafts was simple and safe. In 10 cases, a nitinol mesh-supported venous graft was anastomosed to the circumflex artery and in 15 cases to the RCA. All patients survived the observation period. A total of 72% of the patients underwent control coronary angiography. The patency rate of mesh-supported grafts was 27.8% nine months postoperatively. Conventional vein grafts showed an 85.7% patency, and arterial grafts had a 100% patency. No complications directly related to the implantation of mesh-supported grafts were observed. The promising experimental results of mesh-supported venous grafts could not be reproduced in the study presented. A critical item seems to be correct selection of nitinol mesh diameter, the anastomotic method and fixation of the mesh tube to the venous graft.     

Cerebral revascularization using cadaveric vein grafts

BackgroundUse of cadaveric cryopreserved saphenous vein grafts (CSVGs) has been described for peripheral vascular and coronary revascularization. The aim of this study is to recognize CSVGs as a potential alternative to autologous conduits for extracranial-intracranial (EC-IC) bypass in patients without available or suitable saphenous vein graft or radial artery. We report the short-term patency rate of CSVGs in EC-IC bypass.MethodsWe present our preliminary experience in 10 patients using CSVG for cerebral revascularization. Data regarding operative indications, patient demographics, and bypass patency were collected.ResultsThe average age was 56 years old with equal sex distribution. The indications for the procedure were giant aneurysms in 7 patients, medically refractory vertebrobasilar ischemia in 2, and a skull base tumor in 1. ABO/Rh blood group compatible CSVG was used in each case. Postoperative angiography demonstrated patency in all cases. Quantitative magnetic resonance angiography was performed in 8 patients, demonstrating a mean bypass flow of 109 mL/min ± 19 mL/min (mean ± SE).ConclusionsUse of CSVG for EC-IC bypass has not previously been reported. In our series, the short-term patency rate was 100%, better than that found in cardiac and peripheral vascular series, possibly because of the higher flow in EC-IC bypasses. Our preliminary experience suggests that CSVGs may be an option in patients without available autologous conduits, although longer follow-up is needed to assess long-term patency.     

Surgical Repair of Infected Peripheral Graft and Abdominal Aortic Aneurysm Using Arterial Homograft

We report a case of combined surgical repair including lower limb revascularization (below-knee bypass) and abdominal aortic aneurysm repair using cryopreserved arterial homograft. The patient experienced lower limb ischemia due to repeated thrombosis of a long-infected polytetrafluoroethylene (PTFE) graft, and was also shown to have a complicating abdominal aortic aneurysm. Infection was eradicated with total graft excision and intravenous antibiotics. Two-year patency of the in situ arterial homograft revascularization was demonstrated with hemodynamic and tomographic controls; no degenerations have been found to date. Benefits of the use of in situ arterial homograft for arterial reconstruction may include improved hemodynamics and greater resistance to infection compared to when alloplastic materials are used. Because of the risk of allograft deterioration, close follow-up of the patient is required.     

Effects of a venous cuff at the venous anastomosis of polytetrafluoroethylene grafts for hemodialysis vascular access

INTRODUCTION AND METHODS: The most frequent complication of polytetrafluoroethylene (PTFE) arteriovenous grafts for hemodialysis is thrombotic occlusion due to stenosis caused by intimal hyperplasia. This complication is also known for peripheral bypass grafts. Because the use of a venous cuff at the distal anastomosis improves the patency of peripheral bypass grafts, we considered that it might also improve the patency of PTFE arteriovenous grafts. Therefore, a randomized multicenter trial was carried out to study the effect of a venous cuff at the venous anastomosis of PTFE arteriovenous grafts on the development of stenoses and the patency rates. RESULTS: Of the 120 included patients, 59 were randomized for a venous cuff. The incidence of thrombotic occlusion was lower in the cuff group (0.68 per patient-year) than in the no-cuff group (0. 88 per patient-year; P =.0007). However, the primary and secondary patency rates were comparable. The cuff group tended to have fewer stenoses at the venous and arterial anastomoses when examined with duplex scan. Graft failure was higher in patients with an initial anastomosing vein diameter smaller than 4 mm (7 of 18 [39%]) than in those with a vein diameter of 4 mm or larger (16 of 88 [18%]; P =. 052). Local edema, skin atrophy, and obesity yielded a higher risk on graft failure (23% vs 11%). CONCLUSION: A venous cuff at the venous anastomosis of PTFE arteriovenous grafts for hemodialysis reduced the incidence of thrombotic occlusions; stenosis at the venous anastomosis was reduced. However, this did not result in a better patency rate. Therefore, the venous cuff should not be used routinely. Initial vein diameter and local problems (edema, obesity, or skin atrophy) appear to be the most important risk factors for graft failure.     

Use of superficial femoral vein in the treatment of infected aortoiliofemoral prosthetic grafts

PURPOSE: To assess the use of the superficial femoral vein for the reconstruction of the aortoiliofemoral sector in the treatment of prosthetic infections. METHODS: From December 1995 to November 1999, 12 patients with infection involving a synthetic vascular prosthesis were submitted to thirteen surgical procedures involving partial or total resection of a synthetic vascular prosthesis and restoration of arterial flow with an in situ femoral vein. RESULTS: The overall operative mortality rate was 15.3% (2 out of 3 patients who underwent total graft replacement and 0 out of 9 patients who underwent unilateral graft replacement). Major amputations related to the surgical procedures were performed in two cases (an 87.5% rate of limb salvage). The series was followed up on average for 22 months (range: 6-65 months). No patient presented clinically significant edema or signs of chronic venous insufficiency in the lower limbs used as donors of autogenous venous grafts. All surviving patients presented complete resolution of the infectious signs and symptoms and none of them presented late thrombosis of the venous graft. CONCLUSION: The use of the superficial femoral vein is a good surgical alternative for the treatment of prosthetic infections with minimal venous morbidity of the lower limbs used as venous graft donors. The autogenous venous grafts present good long-term patency and excellent adaptation to the aortoiliofemoral position.     

Critical analysis of the preoperative and operative predictors of aortocoronary bypass patency

A prospective analysis of the angiographic and operative anatomic and reconstructive variables that influenced graft patency was undertaken at the University of Virginia Medical Center in 50 consecutive patients. Postoperative restudy showed that 18 of the 168 grafts performed were occluded due to venous disease, inadequate run-off, or sequential design error. Angiographic artery size was 27% larger than operative estimations; graft patency significantly increased with increasing distal artery diameter, with decreasing venous conduit diameter, and with good graftability rating of the vessels preoperatively. Ejection fraction, the degree of arterial stenosis, and the source of the saphenous vein conduit (the thigh or the lower leg) had no influence on graft patency. Simple grafts had a 96% patency, while sequential grafts had an 80% patency. When design error for sequential grafts was eliminated, the sequential patency rate rose to 88%. For revascularization of small circumflex vessels, consideration should be given to variation in the sequential grafting technique to improve patency in these vessels.     

Inverted T graft: novel technique using composite radial and internal thoracic arteries

BACKGROUND: Multiple arterial revascularization is feasible because of the excellent long-term patency of the arterial grafts compared with venous grafts. We present a new operative technique for multiple arterial revascularization using composite radial and internal thoracic arterial grafts. METHODS: Between January and September 1997, 12 patients had coronary artery bypass grafting with inverted T graft. The indications for inverted T graft were aortic calcification in 4 patients, repeat coronary artery bypass grafting in 1 patient, and total arterial revascularization in 7 young patients. The inverted T graft was constructed by interconnecting the coronary arteries and radial artery with end-to-side and side-to-side anastomoses, and by anastomosing the internal thoracic artery to the side of radial artery. RESULTS: Overall, 38 distal anastomoses (average number per patient, 3.2) were made with an inverted T graft. There were no deaths or perioperative myocardial infarctions. Postoperative angiography disclosed that all of the anastomoses were patent. CONCLUSION: This technique allows multiple arterial revascularizations without technical difficulty. It is useful in patients with aortic calcification, repeat coronary artery bypass grafting patients, and young patients who are candidates for total arterial revascularization.