Which patients should be on renin-angiotensin system blockers after coronary surgery?

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was 'which patients should be on renin-angiotensin system blockers after coronary surgery?' Using the reported search, 12 papers represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. The 12 studies included 5 prospective randomized controlled trials (RCTs) and 1 meta-analysis. One RCT of 2553 stable patients post-coronary artery bypass surgery (CABG) with left ventricular (LV) ejection fraction ≤40% showed that angiotensin-converting enzyme inhibition (ACEI) therapy can and probably should be delayed beyond 7 days due to increased cardiovascular morbidity and mortality associated with immediate postoperative initiation of ACEI treatment. Another study showed that the cardioprotective benefits of ACEI following CABG are persistent with respect to an LV ejection fraction below or above 40% and whether percutaneous coronary intervention (PCI) or CABG was performed. A large multicentre international study of 4224 patients undergoing CABG looking at a composite outcome of rates of cardiac, cerebral and renal events and in-hospital mortality showed that continuous treatment with ACEI compared with no ACEI was associated with reductions of risks of non-fatal events (P = 0.009, odds ratio 0.69, 95% confidence interval 0.52-0.91). Addition of ACEI de novo following surgery was also associated with significant reduction in the risk of the composite outcome (P = 0.004) and of a cardiovascular event (P = 0.04). We conclude that angiotensin-converting enzyme inhibitor treatment plays an important role in minimizing ischaemic events after CABG even in low-risk patients. The cardioprotective benefits of these drugs are persistent at mid- and long-term follow-up, with respect to LV ejection fraction below or above 40% and whether PCI or CABG was performed. Not only continuation of angiotensin-converting enzyme inhibition early after surgery but also adding ACEI de novo postoperatively can be associated with better cardiovascular and renal outcomes.