Clinical and angiographic outcomes associated with surgical revascularization of angiographically borderline 50-69% coronary artery stenoses

Objectives: Coronary artery bypass grafting (CABG) improves outcomes in patients with multivessel coronary artery disease. Bypass of angiographically significant lesions ≥70% is recommended, yet little is known about the incidence/outcomes with bypasses of 50-69% angiographically borderline lesions (ABLs) without fractional flow reserve testing. The objective of this study was to investigate the incidence and outcomes of bypass of 50-69% ABLs.

Methods: Between 2007 and 2013, 3195 patients underwent isolated first multivessel CABG. Patients with an isolated ABL of a major epicardial vessel were included. Outcomes of interest included time to all-cause mortality, and 30-day and 1-year mortality.

Results: Among 350 patients with an ABL, 268 (76.6%) had the vessel containing the ABL bypassed, while 82 (23.4%) did not. The mean follow-up was 4.2 years. Patients with a bypassed ABL were older (66.1 vs 62.5 mean years, P = 0.006) but otherwise similar in sex, comorbidities, diabetes, ejection fraction and number of coronary stenoses. Cardiopulmonary bypass time was longer in patients with bypassed ABLs (104.2 vs 90.4 min, mean, P < 0.001). Unadjusted overall mortality until the end of follow-up was higher among patients with bypassed ABLs (11.6 vs 3.7%, P = 0.034). After multivariable adjustment, the association between ABL bypass and mortality was attenuated (hazard ratio 2.84, 95% confidence interval: 0.87-9.23, P = 0.080). No differences were observed in unadjusted 30-day (1.1 vs 0.0%, P = 0.336) or 1-year mortality (4.1 vs 0.0%, P = 0.062). Repeat revascularization rate of patients with bypassed ABLs was numerically higher (4.1 vs 0.0%, P = 0.107).

Conclusions: In an unselected cohort of patients with ABLs, bypass of borderline 50-69% lesions is frequently performed and not associated with improved long-term survival. Our findings suggest that the routine surgical revascularization of 50-69% ABLs may not be warranted.