Management of unstable coronary syndromes in patients with previous coronary artery bypass grafts following coronary angiography

Objective: To characterize patients who had undergone previous coronary artery bypass grafting (CABG) and who were admitted for coronary angiography for unstable coronary syndromes, to determine the long-term therapy selected for these patients and to assess the outcomes of the intervention. Design: Descriptive retrospective study. Setting: A university-affiliated tertiary care institution. Patients: A total of 129 patients with 1 previous CABG who underwent coronary angiography for myocardial infarction or unstable angina in 1991. Outcome measures: Information regarding initial CABG, indications for cardiac angiography, cardiovascular risk factors, ultimate treatment selected and outcomes at 1 year were abstracted from patients' charts, and outcomes at 1 year were also determined by a patient survey. Results: Seventy-six patients (59%) were given drug therapy, 28 patients (22%) were treated with angioplasty, and 25 (19%) underwent repeat surgery. During their index admissions, of patients given drug therapy, 4 (5.3%) died from myocardial Infarction (MI) and 42 (55%) were discharged without complications; of those undergoing angioplasty, all except 2 were treated successfully (major procedural complications included nonfatal MI in 1 patient [4%] and nonfatal ventricular arrhythmia in 1 patient [4%], as well, reocclusion of the lesions occurred before discharge in 2 patients [7%]); of those undergoing repeat surgery, almost all patients (96%) were discharged, except 1 who died from MI during the postoperative period (there were no procedural complications, but early complications included nonfatal MI in 2 patients [8%], angina in 2 [8%] and nonfatal arrhythmias in II [44%]). Eighty-seven patients (67%) were available for follow-up at 1 year. Of the patients given drug therapy, 3 (6.4%) had died, 14 (30%)had recurrent anginal episodes and 5 (11%) required either angioplasty or CABG. Of the patients who initially received angioplasty, 15 (63%) had recurrent angina but none died, 12 (50%) underwent repeat angioplasty and 2 (8.3%) required repeat CABG. No patients who received repeat surgery died or required further surgery or angioplasty. Three of these patients (19%) had recurrent angina within the first year, Patients in this category also enjoyed a greater degree of symptomatic improvement of coronary artery disease. Conclusions: Patients who had a previous CABG and subsequently presented with MI were more likely to be given conservative drug therapy than those who presented with unstable angina. At 1-year follow-up, recurrent angina occurred more often in the patients treated by angioplasty, less often in patients given drug therapy and least in those who underwent repeat bypass grafting. Restenosis remained a problem, and about 50% of patients treated with angioplasty (without intracoronary stenting) required a second angioplasty within the first year. Patients who were candidates for repeat CABG enjoyed greater symptomatic improvement within the first year.