ANGIOGRAPHIC FEATURES OF VEIN GRAFTS VERSUS UNGRAFTED CORONARY-ARTERIES IN PATIENTS WITH UNSTABLE ANGINA AND PREVIOUS BYPASS-SURGERY

Objectives. The aim of the study was to compare the angio graphic feat ures of culprit coronary lesions located in grafts,vith those in nativ e coronary arteries in patients with unstable angina and previous coro nary artery bypass graft surgery (CABG). Background. Deterioration of angina in patients with previous CABG is usually due to progression of atherosclerosis in coronary arteries or in vein grafts, but the relat ive importance of graft versus native coronary artery disease as well as the morphologic features of the culprit lesions in unstable angina have not been systematically assessed. Methods. Disease progression an d angiographic features of vein grafts and ungrafted and grafted coron ary arteries were assessed in 95 consecutive patients admitted with un stable angina or non-Q wave myocardial infarction with CABG > 6 months previously. All patients were receiving aspirin and heparin, and 46 h ad received streptokinase during the acute phase in a double-blind, pl acebo-controlled study. Coronary and vein angiography was performed wi thin 8 days after admission (mean [+/- SD] 5 +/- 2 days), The most rec ent angiogram served to assess disease progression by quantitative ang iography. Results. The culprit lesion was located in a vein graft in 5 1 patients, an ungrafted coronary artery in 17 and a grafted artery (p roximal and distal to the site of graft insertion) in 9 and was of und etermined site in the remaining 18. The proportion of grafts accountin g for acute disease increased to 85% with CABG greater than or equal t o 5 years. Total occlusion occurred in 25 vein grafts and 4 ungrafted coronary arteries (49% vs. 24%, p = 0.02). Intravessel thrombus was fo und in 18 culprit vein grafts but in only 2 ungrafted coronary arterie s (37% vs. 12%, p = 0.04). Both intravessel thrombus and total occlusi on mere demonstrated in six culprit vein grafts but in none of the ung rafted coronary arteries (12% vs. 0%, p = NS). The prevalence of total occlusion and thrombus was not influenced by trial medication, strept okinase or placebo. Conclusions. Unstable angina in patients with prev ious CABG is most often due to graft disease and is associated with mo re frequent thrombi that are more refractory to medical therapy.