Coronary Angiography and Revascularization Following Coronary Artery Bypass Grafting in British Columbia: Incidence, Predictors and Longer-term Outcomes.

Background: Coronary artery bypass grafting (CABG) is established treatment for subsets of coronary artery disease (CAD). Observational data have characterised significant progression of native coronary as well as graft vessel disease during longer-term follow-up, potentially reducing the benefit of CABG. We sought to assess longer-term outcomes following CABG by determining rates of repeat coronary angiography, revascularization procedures, and survival.

Methods: Data for all patients undergoing isolated CABG in British Columbia between 2001 and 2009 inclusive, and with follow-up until the end of 2013, were retrieved from the British Columbia Cardiac Registry. Cox proportional hazard regression and competing risk regression were performed for survival and subsequent cardiac procedures (coronary angiography, percutaneous coronary intervention [PCI] or repeat CABG).

Results: Data were available from 17,316 patients with a mean age at index CABG of 65.7 ± 9.8 years. At a median follow-up of 8.5 (range 4.0 to 12.9) years, 3185 patients (18.4%) had died, 3135 (18.1%) underwent repeat coronary angiography with or without PCI or repeat CABG, and 11,557 (66.7%) had survived without additional procedures. Of those who underwent angiography, 1459 patients (46.5%) underwent further revascularization. In multivariate analysis, the strongest predictors of long-term mortality were dialysis dependency and age >75, whereas left internal mammary artery utilization and aspirin therapy were protective. Repeat revascularization predicted survival (adjusted hazard ratio 0.76; 95% confidence interval, 0.63-0.92; P = 0.004), whereas angiography alone did not.

Conclusions: Following CABG, patients frequently undergo repeat coronary angiography. Although only a minority of patients receive further revascularization, this appears to be associated with longer-term survival.