Morbidity and Mortality in Patients Undergoing Mitral Valve Replacement at a Cardiovascular Surgery Referral Service: a Retrospective Analysis

Introduction: We aimed to identify predictors of morbidity and mortality in patients undergoing isolated mitral valve replacement. Methods: This is a retrospective cohort study with 164 patients who underwent isolated mitral valve replacement at a referral hospital for cardiovascular diseases, which were performed from January 2011 to December 2016. Data were obtained from medical records, including preoperative, intraoperative, and postoperative information. Statistical analysis was performed to calculate odds ratio (OR), unpaired Student's t-test, and binary logistic regression. P-values < 0.05 were considered significant. Results: A total of 69.5% (n=114) of the patients had a diagnosis of rheumatic disease prior to surgery. Mortality rate was 6.7% (n=11). The most observed complication was the occurrence of postoperative arrhythmias (19.5%). On average, patients remained 5.34 days in the intensive care unit. There was a statistically significant enhanced risk of death among patients with previous diagnosis of endocarditis (OR 5.22, 95% confidence interval [CI] 1,368-19,915; P=0.008), reduced ejection fraction (EF) (< 50%) (OR 9.46, 95% CI 2,61-34,35; P<0.001), and mitral regurgitation (MR) (OR 7.7, 95% CI 1.576-37.545; P=0.004). Patients who died were older than those who survived surgery (P<0.001) and had lower preoperative serum hemoglobin levels (P=0.018). Logistic regression showed age and reduced EF at preoperative evaluation as predictors of death. Conclusion: Older age, reduced serum hemoglobin levels, preoperative diagnosis of endocarditis, reduced EF, and MR were associated with postoperative mortality. Age and reduced EF were predictors of death.