Faculty Bibliography

PURPOSE: To determine why some vein grafts fail, we prospectively studied the relationship between the histologic condition of the greater saphenous vein (GSV) at the time of grafting and subsequent stenosis of the vein graft. METHODS: Ninety-four remnant segments of GSVs were obtained at the time of infrainguinal bypass in 91 patients and were perfusion fixed before histologic and ultrastructural examination. All bypass grafts were evaluated clinically and by duplex ultrasonography at regular intervals from 1 to 30 months after operation. All 24 grafts that developed lesions that caused thrombosis (failed grafts) or flow reduction (failing grafts) underwent arteriography and appropriate operative or other interventional correction of the causative lesion. RESULTS: There was no significant difference in the incidence of coronary artery disease, kidney disease, hypertension, or history of smoking in patients with normally functioning and failed or failing grafts. Diabetes occurred with an increased frequency in failed or failing grafts (p = 0.056). At the time of their insertion, GSVs that subsequently developed significant lesions had thicker walls (0.72 +/- 0.33 mm) compared with normally functioning grafts (0.58 +/- 21 mm; p < 0.02). Most of this difference was related to a significantly thicker intima (0.27 +/- 0.17 vs 0.11 +/- 0.7 mm; p < 0.0001). Another significant finding was the presence of subendothelial spindle-shaped cells greater than five cell layers thick. This occurred more often in pregraft biopsies from grafts that developed significant lesions (70.4% vs 7.5%, p < 0.0001). Electron microscopic examination of these cells demonstrated a subpopulation of poorly differentiated cells with few fibers and many vesicles. Four of 24 (17%) failed or failing grafts had evidence of vein wall calcification at the time of vein grafting. This was seen in only one (1.4%) of 70 normally functioning grafts without lesions (p < 0.005). CONCLUSIONS: We conclude that GSVs with thick and calcified walls or hypercellular intima at the time of grafting are at increased risk of developing intragraft lesions that may lead to graft failure. Frequent duplex ultrasonography surveillance is particularly warranted for such high-risk grafts

Tunis and colleagues attempted to assess the effect of peripheral angioplasty in a large population with descriptive epidemiologic methods. Their study suffered from a vague statement of purpose, inappropriate and inadequate outcome measures, undetermined differences in prevalence of peripheral vascular disease and prevalence of risk factors for bypass/amputation in 1989 versus 1979, no differentiation between levels of amputation or between primary and secondary amputation, lack of a unique ICD-9-CM code indicating angioplasty for peripheral vascular disease of the lower extremities, lack of unique patient identifiers, a mistaken perception of the adoption of angioplasty as 'widespread' in Maryland, and the assumption of uniform coding accuracy throughout the period of study. We conclude that the study design of Tunis et al was inadequate to determine the beneficial effects of angioplasty or bypass surgery in the treatment of peripheral vascular disease. Moreover, the conclusion by Coffman (2) that 'invasive procedures are indicated only for the severely ischemic limb' is completely unsupported by the study data. Physicians should not attempt to apply the results of the study by Tunis et al to individual case situations. It should be further appreciated that the study findings do not provide an adequate basis for policy-making decisions. It is clear that important clinical questions concerning the roles of angioplasty, bypass, and amputation should be answered with more definitive studies

The application of duplex ultrasonography to the diagnosis of venous thrombosis requires validation by comparison of the duplex findings with the results of ascending contrast venography. In this study, 2534 veins were examined by both methods with contrast venography results serving as the standard for comparison. In this setting, duplex ultrasonography proved to be 100% sensitive and 99% specific for venous thrombosis. Duplex ultrasonography is as reliable as venography in the diagnosis of venous thrombosis and has no associated risks or known complication. In addition, duplex ultrasonography provides information regarding pathologic anatomy that is comparable to the detail provided by high-quality venography. The authors conclude that duplex ultrasonography should be the diagnostic method of choice for evaluating patients with suspected venous thrombosis

A three-centre prospective randomized trial was undertaken to compare the efficacy of in situ and reversed saphenous vein grafts for long bypasses to tibial and peroneal arteries. Of 162 patients entered into the study, 82 received an in situ graft and 80 a reversed vein graft. All operations were for limb salvage and the two groups of patients were well matched for age, sex, incidence of diabetes, smoking habits and coronary artery disease. At a maximum follow-up of 3 years there were 48 primary graft failures: 19 in the in situ group and 29 in the reversed vein group. Of these, three in situ grafts and seven reversed grafts were salvaged by secondary intervention. Secondary cumulative patency rates calculated at 3 years after operation were 68 and 66 per cent respectively for in situ and reversed grafts (P not significant). Cumulative limb salvage rates were 78 per cent for in situ grafts and 87 per cent for reversed grafts (P not significant). Separate analysis of a subgroup with small veins (< or = 3.5 mm minimum diameter) showed cumulative patency rates at 2 years of 74 per cent for in situ grafts and 60 per cent for reversed grafts (P not significant). These results indicate that for veins > 3.5 mm in diameter the in situ and reversed techniques for operation are equally effective. Some doubt remains about the best way of using smaller veins; a large number of such veins need to be studied to resolve this question

BACKGROUND. A significant number of vascular injuries occur with the use of percutaneous diagnostic and therapeutic procedures. This study was done to indicate the types of these injuries and their management. METHODS. Over a 30-month period, 55 patients required operation for vascular complications after percutaneous femoral procedures including infrarenal arteriography (six patients) and angioplasty (22 patients), coronary angiography (16 patients) and angioplasty (five patients), and aortic balloon pump insertion (six patients). RESULTS. The 14 iliac and 41 femoral artery injuries included 29 pseudoaneurysms, six lacerations with persistent bleeding, seven dissections, six occlusions, three ruptures, two arteriovenous fistulas, and two large hematomas. Control for all femoral and distal external iliac artery lesions was obtained solely through a groin incision in 45 (82%) patients. Our technique for exposure of the external iliac artery through the groin is described. A separate retroperitoneal incision was necessary in 10 patients because of proximal injury, massive pseudoaneurysm, morbid obesity, or heavily scarred groins. In this series 34 lateral suture repairs, 11 interposition or bypass grafts, four patch angioplasties, one endarterectomy, three thrombectomies, and two hematoma evacuations were performed. Although no limb loss occurred, we encountered nine wound complications, five myocardial infarctions, and two deaths. CONCLUSIONS. This experience shows the wide variety of vascular complications caused by percutaneous procedures and the different techniques necessary for their management

Controversy continues as to whether percutaneous transluminal angioplasty (PTA) or surgical revision is the ideal modality for the treatment of failing grafts. This prompted a histopathologic analysis of failing human vein graft segments subjected to ex vivo balloon dilatation to define variables responsible for the discrepant results. Fifteen vein graft lesions from 14 patients with failing infrainguinal bypasses were recovered after surgical excision. Each graft lesion was focal and uniform in length (2.1 +/- 0.3 cm). Rings sectioned from adjacent regions of each vein graft lesion before and after balloon inflation were processed for histologic study, photomicrography, and image analysis. Angioplasty balloon size was selected on the basis of preoperative arteriograms. Graft lesions were divided into three groups based on lesion thickness and the degree of fibrosis and cellularity seen on sections stained with Masson's trichrome. The luminal area before angioplasty was not significantly different for the three groups (p > 0.2). Vein grafts with thick intimas (group 1) had significantly less luminal dilatation after angioplasty as compared with less thick intimal lesions (groups 2 and 3; p < 0.001). Those lesions with varying degrees of cellularity (groups 2 and 3) showed no significant differences in luminal diameter after angioplasty. However, the cellular lesions in group 2 consistently formed multiple intimal flaps that could produce PTA failures even with good luminal restoration. The varying histology of vein graft lesions and associated differences in intimal thickness and cellularity may be responsible for the inconsistent results following PTA. Estimates of wall thickness before angioplasty, particularly in the intimal area, may be helpful in evaluating which lesions might benefit most from PTA