Using decision-analysis and meta-analysis to predict coronary artery bypass surgical outcomes – a model for comparing off-pump surgery to miniaturized cardiopulmonary bypass circuits

Abstract

Coronary artery bypass (CABG) surgery with cardiopulmonary bypass (CPB) has been the “gold standard” for many years. However, methods to conduct off-pump coronary artery bypass (OPCAB) surgery with a beating heart have decreased the use of CPB. Improvements in cardiopulmonary bypass technology, using low-prime circuits with retrograde autologous prime, have demonstrated a reduction in blood use while maintaining the surgical advantage of increased revascularization associated with on-pump surgery. A meta-analysis of published randomized clinical trials was used to compare the outcomes. These outcomes included the number of grafts, hospital length of stay, and transfusion rate. They were then incorporated into a decision-analysis model to compare OPCAB with the on-pump surgery, using both conventional high-prime (HP) and low-prime circuits with retrograde autologous prime (LP/RAP). The meta-analysis of randomized clinical trials revealed that OPCAB surgery had 0.33 less grafts (p < .05), a reduction of 0.97 days in hospital length of stay (LOS) (p < .05), and a 63.2% reduction in percentage of patients transfused (p < .05). Based on the decision-analysis model, a relatively low major event rate (defined as myocardial infarction, need for angioplasty or surgery) at 4 years of 2% can eliminate the savings associated with OPCAB when compared to a low-prime circuit with RAP. Using a 5% major event rate at 4 years, the predicted cost savings of LP/RAP over OPCAB is $510 per patient or $51,036,746 per 100,000 patients. The development and implementation of low-prime circuits with retrograde autologous prime is an import step in matching the outcomes associated with OPCAB surgery.