[Pseudo-occlusion of the femoro-popliteal bypass].

Introduction: Pseudo-occlusion of femoro-popliteal/crural (F-P/Cr) bypass occurs when a patent graft is clinically indistinguishable from a thrombosed graft because of reduced flow [1]. The aim of this paper is the presentation of 24 new cases which, as far as we know, have not been published in Yugoslav medical literature.
Case Report: The group consisted of 20 men and 3 women (aged 28 to 71 years, mean 61.95) with 24 cases of "pseudo-occlusion" of the F-P/Cr bypass. More details are presented in Tables 1 and 2. Saphenous vein graft was used for the reconstruction in 19 patients, and Dacron in 5 subjects. "Pseudo-occlusion" was symptomatic in all 24 patients. Fifteen patients had pain at rest, seven presented disabling claudication, and 2 foot gangrene. The mean time interval between primary operation and occurrence of new symptoms was 25.41 (4-84) months (Table 2). In 15 patients control angiography showed hemodynamically significant lesions in inflow tract, and in 9 subjects in outflow tract. Of the total number of inflow tract lesions, there were 3 late occlusions of previously implanted aorto-femoral graft (1, 3 and 17, Table 1), and in other 21 patients lesions of the native aorto-iliac segment. In 8 patients with changes in outflow tract, a distal progression of atherosclerotic disease was found, while one patient (number 8) had intraoperative lesion of the popliteal artery with vascular clamp. All 24 patients were treated operatively. The early postoperative result was favourable in all 24 (100%) patients. Patients were followed-up from 3 months to 5 years (mean 29.625 months). In this period one (4.1%) late graft occlusion was followed by major limb amputation. Four (16.6%) patients died with patent graft.
Conclusion: 1. Pseudo-occlusion of the F-P/Cr bypass occurs when a patent graft is clinically indistinguishable from a thrombosed graft because of reduced flow. 2. Pseudo-occlusion may be provoked by changes in inflow and outflow tract. 3. Pseudo-occlusion is not associated only with saphenous vein graft. 5. Recurrence of symptoms, loss of previously palpable distal pulses and reduction of Doppler indices in a previously patent F-P/Cr bypass graft, can indicate pseudo-occlusion. Early diagnosis provides a simple and safe treatment.