Multiple arterial grafting is associated with better outcomes for coronary artery bypass grafting patients

Background — Observational studies have shown better survival in patients undergoing coronary artery bypass grafting (CABG) with 2 arterial grafts compared with 1. However, whether a third arterial graft is associated with incremental benefit remains uncertain. We sought to analyze the outcomes of 3 versus 2 arterial grafts during CABG. As a secondary objective, we compared CABG with 2 or 3 arterial grafts (multiple arterial grafts [MAG]) with CABG using a single arterial graft (SAG).

Methods — Retrospective cohort analyses of all patients undergoing primary isolated CABG in Ontario, Canada, from October 2008 to March 2016. Propensity score matching was performed between patients with 3 arterial grafts (3Art group) versus 2 (2Art group). The primary outcome was time to first event of a composite of death, myocardial infarction, stroke, and repeat revascularization (major adverse cardiac and cerebrovascular events). Additional analyses were performed to evaluate the association between MAG versus SAG and long-term outcomes using propensity score matching.

Results — Fifty thousand, two hundred thirty patients underwent isolated CABG during our study period; 3044 (6.1%) and 8253 (16.4%) patients had 3 and 2 arterial grafts, respectively, resulting in 2789 propensity score matching pairs for the primary analyses. Mean and maximum follow-up was 4.2 and 8.5 years, respectively. Radial artery grafting was more common in the 3Art versus 2Art group (79.3% versus 65.6%, P<0.01). In-hospital outcomes were not significantly different, including death (3Art 0.8% versus 2Art 0.5%, P=0.26). Up to 8 years, there were no differences in major adverse cardiac and cerebrovascular events (3Art 27%, 95% confidence interval [CI], 24% to 30% versus 2Art 25%, 95% CI, 22% to 28%; hazard ratio [HR], 1.08, 95% CI, 0.94–1.25), death (HR, 1.08; 95% CI, 0.90–1.29), myocardial infarction (HR, 1.15; 95% CI, 0.87–1.51), stroke (HR, 1.39; 95% CI, 0.95–2.06), or repeat revascularization (HR, 1.04; 95% CI, 0.82–1.32). When evaluating MAG versus SAG, 8629 patient pairs were formed using propensity score matching. At 8 years, cumulative incidences of major adverse cardiac and cerebrovascular events (HR, 0.82, 95% CI, 0.77–0.88), survival (HR, 0.80; 95% CI, 0.73–0.88), repeat revascularization (HR, 0.79; 95% CI, 0.69–0.90), and myocardial infarction (HR, 0.83; 95% CI, 0.72–0.97) were superior in the MAG group.

Conclusions — CABG with 3 arterial grafts was not associated with increased in-hospital death nor with better clinical outcomes at 8-year follow-up, compared with CABG with 2 arterial grafts. MAG was associated with superior outcomes compared with SAG.