Long-term Outcomes after Off-Pump or Conventional Coronary Artery Bypass Grafting within a Veteran Population

Abstract

Objective

Recently published data indicate that outcomes for off-pump coronary artery bypass grafting (OPCABG) may be inferior to conventional CABG (cCABG) within the Veteran population, but this has been only partly addressed within high-volume off-pump centers. Here, we seek to examine the long-term outcomes for these patients within the Veteran population at a single institution well experienced with OPCABG.

Methods

With the use of a preexisting in-house database, all patients who had undergone isolated CABG from 2000 to 2011 (n = 1125) were identified. From these data, 18 demographic and risk factors were compared and used to create a propensity score, which was used for matching between groups (OPCABG vs cCABG). The primary end point examined was death. Survival was analyzed using the Kaplan-Meier method and the log-rank test. Groups were compared using a Student t test or Fisher exact test, where appropriate.

Results

Unmatched OPCABG and cCABG groups were found to have significant differences in risk factors, with the OPCABG being a higher-risk population by ejection fraction, chronic obstructive pulmonary disease status, age, and renal function, among others (all P < 0.05). Kaplan-Meier analysis of the unmatched groups demonstrated an increased mortality rate within the higher-risk OPCABG group (P = 0.0002). With the use of propensity score matching, 337 OPCABG patients were then matched to 337 cCABG controls. Comparison of demographic and risk factors between these matched groups did not demonstrate any statistically significant difference. When Kaplan-Meier analysis was performed for the matched groups, there was no statistically significant difference in survival. In addition, in the matched data set, OPCABG patients had a shorter average length of stay (8.2 vs 9.7 days, P = 0.022), shorter operative time (205 vs 270 minutes, P < 0.001), and lower rate of bleeding complications (0.9% vs 3.6%, P = 0.032).

Conclusions

In this high-volume off-pump center, matched OPCABG survival is similar to cCABG. Although recent data indicate that OPCABG survival may be worse than that of cCABG within the entire Veteran population, in centers well experienced with OPCABG, this does not seem to hold true. In addition, the benefit of decreased length of stay and lower morbidity rates seems to be significant. Further study of the long-term outcomes of OPCABG in high-volume Veteran's centers is warranted.