Risk score for predicting in-hospital/30-day mortality for patients undergoing valve and valve/coronary artery bypass graft surgery

Background: Risk scores are simplified linear formulas for predicting mortality or other adverse outcomes at the bedside without personal digital assistants or calculators. Although risk scores are available for valve surgery, they do not predict short-term mortality (within 30 days of surgery) after hospital discharge. Methods: New York's Cardiac Surgery Reporting System 2007 to 2009 data were matched to vital statistics data to identify valve surgery with and without concomitant coronary artery bypass graft (CABG) surgery deaths occurring in the index admission or within 30 days after the procedure in any location. Risk scores were created to easily predict these outcomes by modifying more complicated logistic regression models. Results: There were 13,455 isolated valve surgery patients and 8,373 valve/CABG surgery patients in the study. The respective in-hospital/30-day mortality rates were 4.03% and 6.60%. There are 11 risk factors comprising the isolated valve surgery score, with risk factor scores ranging from 1 to 8, and the highest observed total score is 28. There are 14 risk factors comprising the valve/CABG surgery score, with risk factor scores ranging from 1 to 6, and the highest observed total score is 19. The scores accurately predicted mortality in 2007 to 2009 as well as in 2004 to 2006, and were strongly correlated with complications and length of stay. Conclusions: The risk scores that were developed provide quick and accurate estimates of patients' chances of short-term mortality after cardiac valve surgery.