Infective Endocarditis, Predictors of Mortality and Morbidity

Objectives: Infective endocarditis is a disease with high mortality and morbidity. The primary outcome of this study is to assess factors associated with in-hospital mortality in patients undergoing valvular surgery for infective endocarditis. The secondary outcome of this study is to assess the incidence and factors associated with post-operative morbidity; namely post-operative stroke, renal failure and dialysis, complete heart block and return to theatre for bleeding or tamponade. Methods Between the years of 2015 to 2019, a total of 89 patients underwent surgery for infective endocarditis at Fiona Stanley Hospital. Data was collected from the Australia and New Zealand Cardiac Surgery Database from 2015 to 2019 as well as patients electronic medical record (EMR). A number of preoperative and perioperative factors were assessed in relation to patient mortality and morbidity. Univariate and multivariate logistical regression analysis was done to assess for the association between factors and in-hospital mortality and morbidity Results: A total of 89 patients underwent surgery for infective endocarditis, affecting 101 valves. The mean age of patients was 53.7. A total of 79 patients had a positive blood culture pre-operatively, with Staphylococcus Aureus being the most frequently cultured organism (39%). Fourteen patients (16%) were deemed emergent and underwent surgery within 24 hours of review. A total of five patients died within their hospital stay postoperatively. Variables significantly associated with mortality on univariate analysis were intravenous drug use, emergent surgery, perioperative dialysis, perioperative inotropes, cardiopulmonary bypass (CPB) time and cross clamp time (CCT). Only CBP time was significantly associated with mortality on multivariate analysis. A total of 19 patients (21%) required hemodialysis after surgery, 10 patients sustained a postoperative stroke (11%), 15 patients required to return to theatre (17%) and 11 patients developed a complete heart block post operatively (12%). Conclusion There are a number of factors associated with mortality and morbidity in patients undergoing surgery with infective endocarditis. Our study demonstrates a lower mortality rate in these patients than previously quoted in literature. Exposure of prolonged CBP times was the only factor significantly associated with increased mortality on multivariate analysis, although a critical perioperative state was highly significant on univariate analysis.