The risks of reoperative coronary artery bypass in chronic ischemic cardiomyopathy: results of the CABG Patch Trial

Abstract

Background: Coronary artery bypass grafting in patients with chronic ischemic cardiomyopathy is increasing in frequency, as is reoperative bypass. However, there exist very little data on early outcomes of patients with severe left ventricular dysfunction undergoing reoperation. Hence, we tested the following hypotheses: (1) in the presence of severe left ventricular dysfunction, repeat coronary bypass carries a higher surgical mortality than the primary operation and (2) among reoperative patients with left ventricular dysfunction, the surgical mortality is higher in those with the lowest preoperative ejection fractions (EFs).

Methods and results: We studied 1429 patients in the CABG Patch Trial, a prospective, controlled study involving 37 centers, to determine rates of early morbidity and mortality in reoperative coronary bypass patients with a reduced EF (<36%). Among patients with an EF <25%, reoperation carried a surgical mortality of 9.3%, compared with 4.3% for first-time bypass (P=NS by chi(2) analysis). With an EF <36%, surgical mortality rates were 12.0% and 4.6% for repeat and primary bypass, respectively (nominal P<.001). Among reoperative patients, there was no difference in surgical mortality at an EF <25% compared with 25% to 35%. Compared with individuals undergoing the primary bypass, reoperative patients were less stable on leaving the operating room and were more than twice as likely to sustain a postoperative myocardial infarction, cardiogenic shock, or open chest resuscitation.

Conclusions: Reoperative coronary artery bypass grafting in chronic ischemic cardiomyopathy is associated with substantially higher rates of early morbidity and mortality than the initial operation and seems to be primarily attributable to postoperative heart failure.