Renin–angiotensin blockade after aortic valve replacement: A review based on current literature

Aortic stenosis is the most common valvular heart disease and is known to augment the risk of cardiovascular morbidity and mortality. Aortic valve replacement (AVR), either surgical (SAVR) or transcatheter (TAVR), is the only treatment that has consistently shown improved survival in these patients. From 2009 to 2015, there was a 123% increase in the number of AVR procedures in Medicare beneficiaries. This number is expected to further increase with the improving technological advancement and broader utilization of TAVR. Nearly two-thirds of post-SAVR patients die within 10 years, and half of the postTAVR patients die within five years of the procedure. Renin–angiotensin system (RAS) blockade with angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs) has been associated with improved survival in patients with aortic stenosis. Currently, there are no recommendations regarding the use of RAS blockers post-AVR. Owing to the increasing number of these patients and the need for improved long-term outcomes in this population, we sought to systematically review the literature to investigate the benefits of RAS blockers in the patients who had undergone SAVR and TAVR. We performed a search of PubMed, Embase, and Cochrane central utilizing the keywords ‘Renin– Angiotensin Inhibitor’ OR ‘angiotensin receptor blocker’ OR ‘angiotensin-converting enzyme inhibitor’ AND ‘aortic valve replacement’ including transcatheter or surgical in all combinations, with limits of humans activated. No restriction for language or publication year was used. Once identified, full manuscripts were extracted to assess against a priori inclusion criteria. The articles were considered for inclusion if they had the comparative data available for with or without the use of ACE or ARB in aortic stenosis patients who underwent AVR. The outcome of interest was all-cause mortality. Due to a significantly high heterogeneity noted in the meta-analysis, we are reporting our findings only as a systemic review. Our initial search yielded 336 articles. After careful screening, we ended up with five articles. All the included studies were observational retrospective cohort studies. Our results showed that the use of RAS blockers after AVR was significantly and consistently associated with a reduction in mortality; see Table 1 for the details. The effect size in the form of odds ratio ranged from 17% to 69% reduction in all-cause mortality with the RAS blockade. Our result shows that RAS blocker therapy is associated with a statistically significant improvement in survival in patients after AVR. Previous recommendations for secondary prevention postoperatively in patients with AVR have consisted of supervised exercise, diet education, and stress and depression management that has resulted in improvement in functional status and quality-of-life. Our literature review is the first one to show mortality benefit consistently seen across the studies. Left ventricular (LV) dysfunction and myocardial hypertrophy is a consequence of long-standing pressure overload due to aortic stenosis. Due to their antihypertensive effects; RAS blockers have been shown to regress LV hypertrophy in hypertensive patients. Similarly, AVR is expected to reduce LV afterload, which should regress LV hypertrophy. In a randomized study of 12 months, RAS blockade has also been found to be an independent predictor of regression in LV mass index in a multivariate-adjusted model. This