Comparative Study of Robotic Vs. Conventional Reoperative Cardiac Bypass Surgery and Valve Surgery: A Propensity Model
BACKGROUND: Reoperative surgery for Coronary Artery Bypass Grafting (CABG) and mitral valve repair (MVR) offers a distinct survival and symptomatic benefit. Even though there have been previous attempts to compare outcomes in the two groups the dissimilarities between patient groups hindered validation of the results. We hypothesize that using a risk based propensity model we will be able to compare the outcomes in the two groups with confidence. METHODS: In our STS database for the years 2011 to 2013, we could identify 127 patients which fulfilled the requirement of prior surgical interventions. We utilized a propensity matched algorithm to match the two groups based on age, gender, BMI, presence of diabetes, dyslipidemia, hypertension, COPD, serum creatinine, smoking status, previous CABGs, number of diseased vessels, presence of atrial fibrillation and presence of heart failure and actual surgical procedure (CABG and MVR). The comparison of the matched pairs was done using a Wilcoxon-rank sign test for quantitative variables and the McNemar test for qualitative variables. All tests were performed using SAS 9.3(Cary, NC). RESULTS: 22 matched pair could be identified through the optimal propensity algorithm. . Operative mortality was clearly lower in the robot-assisted cases (14% Vs 27%, p< 0.1) but did not reach significance. The usage of CPB was significantly lower in robot-assisted procedures (63 Vs. 122, p< 0.03). Intraoperative blood usage (41% Vs 86%, p <0.004) and surgery time (259 Vs 322, p<0.006) were significantly reduced in robotic cases. Major complications were not different in the 2 groups (p value ~ 1). However there was a non-significant yet higher readmission rate in robotic (39% Vs 20%, p <0.48) CONCLUSION: Robotic reoperative surgery for MVR and CABG does offer advantages in terms of reduced costs and hospital stay however it is unclear to arrive at a conclusion with our data for reduced post surgical mortality and complications.