ROOBY Trial Follow-up Extension

Overview

The Department of Veterans Affairs "Randomized On/Off Bypass" (ROOBY) Trial (CSP #517) was funded in 2001. ROOBY was designed to compare the short-term (30-day) and intermediate-term (1-year) outcomes for patients undergoing off-pump versus on-pump coronary artery bypass graft (CABG) procedures. The ROOBY trial reported a significantly higher 1-year adverse composite outcome rate (i.e., all-cause death, non-fatal myocardial infarction (MI) and/or repeat revascularization) for off-pump versus on-pump patients. ROOBY documented that a higher percentage of off-pump patients received fewer grafts than originally planned (i.e., off-pump patients were less completely revascularized) as compared to on-pump patients. Across all anatomic regions of the heart, the 1-year graft patency rates were significantly lower for off-pump CABG patients. Based on these ROOBY trial initial findings, critically important clinical questions related to the long-term efficacy, stability and durability of the off-pump versus on-pump techniques have been raised. Extending the original ROOBY trial, this CSP #517 follow-up study (CSP 517-FS) will evaluate the longer-term impact of off-pump versus on-pump surgical approaches upon the future occurrence of major adverse cardiovascular events (MACE).

A debate is ongoing as to the potential longer-term benefits of off-pump versus on-pump treatments. A recent meta-analysis summarized 12 randomized trials with follow-up extending beyond 1-year; with a significant increase documented in the late off-pump repeat revascularization and mortality rates. As a very large single center study with longer-term follow-up, a Beijing hospital study reported that their early minor advantages identified for off-pump surgery (n = 3,266) were offset at 4.5 years by an increased risk for cardiac death, acute MI and repeat revascularization as compared to an on-pump (n = 3,399) approach. The OCTOPUS study (a multi-center randomized trial based in the Netherlands) concluded that there was no difference in off-pump versus on-pump procedures for 5-year cardiac outcomes. However, OCTOPUS critics raised questions as to whether this study of only 281 low-risk patients was adequately powered to detect 5-year clinically relevant differences. The ROOBY trial represents the only US-based, multi-center trial that will be adequately powered to detect clinically relevant, statistically significant differences in these long-term MACE (i.e., all cause mortality, non-fatal myocardial infarction, and/or repeat revascularization) outcomes. Recognized as a landmark study, ROOBY has resulted in important contributions including 10 manuscripts, 2 letters to the editor, and an invited editorial. As of October 11, 2012, over 182 manuscripts (not including any self-citations) had referenced the ROOBY trial's original 2009 publication. Most recently, the ROOBY trial was identified in the 2012 Almanac of adult cardiac surgery, where the national society journals present selected research that has driven recent clinical care advances. Additionally, ROOBY was judged independently by the March 2012 Cochrane systematic review as one of only three, multi-center trials that had been conducted to-date with a low risk of bias. The original ROOBY trial's enrollment was initiated in February 2002 and ended in June 2007. Given the passage of time, it is now possible to obtain at least 5 years of follow-up to identify these critically important longer-term MACE endpoints for all ROOBY patients. For the earliest ROOBY patients enrolled, their MACE outcomes for up to (and potentially beyond) 10 years post-CABG may be assessed. These MACE endpoints will be ascertained using a combination of VA and non-VA database extracts as well as by chart reviews. In summary, the CSP 517-FS proposed study represents the first, large scale, US-based, multi-center, randomized, controlled off-pump versus on-pump trial that will have adequate power to assess major adverse cardiovascular events beyond 5 years - comparing the long-term effectiveness of these procedures to guide future adult cardiac surgical clinical decision-making processes. The Department of Veterans Affairs "Randomized On/off Bypass" (ROOBY) Trial (CSP#517; NCT00032630) was funded in 2001.