Chronic total occlusions and coronary artery bypass grafting outcomes

Objective: To investigate the association between the presence and grafting of chronic total occlusions (CTOs) and coronary artery bypass grafting (CABG) outcomes.

Methods: This was a post hoc analysis of the Randomized Endograft vs Open Prospective (REGROUP) trial, which randomized veterans undergoing isolated on-pump CABG to endoscopic versus open vein harvest (2014-2017). Patients were stratified on the basis of the presence of at least 1 CTO vessel (a 100% occluded coronary lesion for greater than or equal to 3 months) and according to whether all CTO vessels were bypassed. Rates of major cardiac adverse events (MACE) were compared.

Results: At least 1 CTO was present in 453 of 1149 patients (39.4%). Over a median follow-up of 4.7 years (interquartile range, 3.84-5.45), MACE rates were 23.4% versus 22.2% for the CTO versus no CTO group, respectively (adjusted hazard ratio [aHR], 0.92; 95% confidence interval [CI], 0.70-1.20). MACE rates for patients with complete CTO grafting versus not were 23.1% versus 25.0%, respectively (aHR, 0.95; 95% CI, 0.57-1.57). In patients with right coronary dominance undergoing left anterior descending artery grafting, bypassing a right coronary artery CTO was associated with significantly lower rates of all-cause mortality (aHR, 0.38; 95% CI, 0.17-0.83).

Conclusions: In this REGROUP trial subanalysis, neither CTO presence or complete grafting of CTO vessels was associated with significantly different rates of MACE. However, the finding of possible survival benefit among a subgroup of patients undergoing grafting of a dominant RCA CTO vessel alongside left anterior descending artery grafting warrants additional study.