Prophylactic Intra-Aortic Balloon Counterpulsation in High Risk Cardiac Surgery: The Pinball Program of Research and Linked-Data Pilot RCT

Abstract

Purpose: Prophylactic intra-aortic balloon pump (IABP) therapy in high risk patients undergoing CABG surgery may reduce mortality. However, the quality of the available evidence is low and there is substantial variability in use. Although there is a need to generate high quality evidence, several issues first need to be addressed, including equipoise for enrolment into a RCT, delivery of prophylactic IABP in a trial setting and study recruitment rate. The aim of the PINBALL pilot RCT is to address these issues and assess the feasibility of a definitive trial. Methodology: PINBALL is a multidisciplinary collaboration involving the ANZSCTS Database Program. The current pilot study builds on a program of registry-linked research, nesting an RCT within a high quality database. Patients are screened for eligibility i.e. they have no exclusion criteria and are listed for CABG surgery, the treating surgical team is uncertain as to the benefit of prophylactic IABP and there is one or more of: severely impaired left ventricular function, recent or ongoing myocardial ischaemia, or critical coronary artery stenosis. Results: The pilot RCT has screened 100 and enrolled 17 participants at five centres (planned sample size is 40), randomising patients to either prophylactic IABP in addition to standard care, or standard care alone. Recruitment rate is currently 0.5 (range 0.1-0.7) participants per site per month. Treatment according to enrolment status occurred in 7/8 (88%) and 9/9 (100%) of participants in the IABP and no IABP arms respectively. Conclusion: Randomisation to an IABP trial appears feasible, however current recruitment rate is low, suggesting a definitive trial would require a substantial number of sites and time.