Faculty Bibliography

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

Purpose: The purpose of this study was to review our experience with externally supported, knitted Dacron grafts used for axillofemoral bypass. Methods: Retrospective analysis was performed on records of 79 consecutive axillofemoral bypass graft operations performed on 77 patients from January 1978 to April 1990. Results: The mortality rate within 30 days of operation was 5% (four of 79); 36 patients died in the follow-up period; none died of graft causes. During this 12-year period (mean follow-up 42 months) three patients were unavailable for follow-up. The primary patency rate was 78% at 5 years and 73% at 7 years, with no change thereafter. Neither the graft configuration (i.e., axillounifemoral [n = 50] vs axillobifemoral [n = 29]) nor patency of the superficial femoral artery had an impact on the primary patency rate. Patients who underwent surgery for disabling claudication (n = 30 grafts) had a primary patency rate of 80% at 6 years compared with 65% at 6 years for those who required surgery for limb salvage (n = 49 grafts); the difference was not significant (p = 0.37). Actuarial survival of patients with axillofemoral grafts was 23% at 10 years compared with 72% in a concurrent population of patients with aortofemoral bypass (p < 0.001). Conclusion: These findings indicate that axillofemoral bypass grafts may be appropriate for high-risk patients with severe aortoiliac disease who require revascularization for either limb salvage or incapacitating claudication. $$:

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