Renin-angiotensin system inhibition and outcome after coronary artery bypass grafting: A population-based study from the SWEDEHEART registry

Background: Renin-angiotensin system (RAS) inhibitors are recommended postoperatively to coronary artery bypass grafting (CABG) patients with reduced left ventricular function, diabetes, hypertension or previous myocardial infarction, but not to remaining patients. The aim of the study was to assess the long-term utilization of RAS inhibitors after CABG in patients with and without indication for treatment, and its association with outcome.

Methods: All patients (n = 28,782) not meeting exclusion criterion in Sweden who underwent isolated first time CABG from 2006 to 2015 were included using nationwide registries. The association between treatment and outcome was assessed using adjusted Cox regression models with time-updated data on medications. The primary outcome was major adverse cardiovascular events (MACE), defined as all-cause mortality, stroke and/or myocardial infarction.

Results: At baseline 26,284 (91.3%) of the patients had at least one indication for RAS inhibition while 2498 (8.7%) had not. RAS inhibitors were dispensed to 77.0% and 29.7% of patients with and without indication respectively. Dispense declined over time. RAS inhibition was associated with a reduction in MACE in the whole study population (adjusted hazard ratio (aHR) 0.88, 95% confidence interval (95% CI) 0.83-0.93, p < 0.0001), and in patients with (aHR 0.87 95% CI: 0.82-0.93, p < 0.0001) and without indication (aHR 0.75, 95% CI: 0.58-0.98, p = 0.034).

Conclusions: RAS inhibition is underutilized after CABG. The use of RAS inhibitors was associated with a reduction in MACE, both in patients with and without indication for treatment. The results suggest that RAS inhibition is beneficial for all CABG patients. Randomized controlled trials are necessary to confirm this hypothesis.