Does prior coronary bypass surgery present a unique risk for reoperative valve surgery?

Prior coronary surgery has been associated with a higher incidence of adverse outcomes after reoperative cardiac surgery compared with previous valve surgery. It is unclear whether this association is primarily due to greater patient comorbidity or the technical challenges posed by mediastinal reentry and operation in the setting of previous bypass grafts. This study was therefore designed to examine whether previous coronary artery bypass grafting (CABG) is a significant risk factor for adverse outcomes after reoperative cardiac surgery.

From a prospective database of 1,093 consecutive adults who underwent reoperative cardiac surgery between 2000 and 2010, 363 patients undergoing isolated reoperative valve surgery were divided according to whether or not the previous surgery included CABG (group I, n = 133) or not (group II, n = 230). Propensity-adjusted multivariate analysis was performed in order to determine independent predictors of any morbidity or mortality, or decreased survival.

Patients in group I were more likely to be elderly (p < 0.001), and have greater body mass indexes (p = 0.04), low ejection fractions (p = 0.001), and comorbidities of cerebrovascular disease (p = 0.04), peripheral vascular disease (p = 0.003), and diabetes (p < 0.001) compared with group II. Patent grafts were present in 94% (n = 111). Although group I patients were significantly more likely to experience major postoperative complications and had worse survival, after propensity adjustment no significant difference was observed in either any morbidity or mortality (p = 0.4) or in survival (p = 0.4).

A history of CABG does not appear to present a unique risk in reoperative valve surgery. The major determinant of adverse outcomes is morbidity, not prior bypass grafts.