Changing pattern of valve surgery

Background: Advances in surgical technique and perioperative myocardial protection have reduced the risk of aortic and mitral valve surgery. Improved methods of valve repair have reduced the proportion of patients who require valve replacement. However, patients who require valve replacement often have advanced disease and/or extensive calcification and may therefore be at increased risk for perioperative morbidity and mortality. Methods and Results: We reviewed the results of 2898 patients who underwent aortic (AVR) or mitral (MVR) valve replacement at the Toronto Hospital. We compared patients who underwent surgery between January 1982 and December 1986 (early group) with those who were operated on between January 1989 and December 1993 (late group). The univariable and multivariable predictors of postoperative low-output syndrome (LOS) and operative mortality (OM) were determined for each time period. A total of 1779 patients underwent AVR (late, n=997; early, n=782). Multivariable analyses revealed that the late group had significantly more patients with independent pre-epidemiology operative risk factors for both OM and LOS. Despite the greater proportion of high-risk patients, the incidence of postoperative LOS was lower in the late group (10% versus early, 14%; P=.012). There was no difference in OM between the two groups (late, 3.4% versus early, 3.7%; P=.732). A total of 1119 patients underwent MVR (late, n=493; early, n=626). Compared with the early group, the late group had significantly more patients with preoperative multivariable risk factors for OM and LOS. There was no difference in postoperative LOS (late, 19% versus early, 21%; P=.361) or OM between the two groups (late, 5.8% versus early, 6.9%; P=.432). Conclusions: Despite an increase in high-risk patients, there was no significant increase in mortality or morbidity associated with aortic or mitral valve surgery.