VIEWPOINTSInhibition of the renin-angiotensin system in the cardiorenal syndrome with anaemia a double-edged swordVlahakos, Demetrios V.a; Tsioufis, Costasb; Manolis, Athanasiosc; Filippatos, Gerasimosd; Marathias, Katerina P.e; Papademetriou, Vasiliosf; Mancia, GiuseppegAuthor Information aRenal Unit, Attikon University Hospital b1st Department of Cardiology, Ippokration University Hospital, National and Kapodistrian University of Athens Medical School cDepartment of Cardiology, Asklepeion Hospital, Voula d2nd Department of Cardiology, Attikon University Hospital, National and Kapodistrian University of Athens Medical School eOnassis Cardiac Surgery Center, Athens, Greece fHypertension Research Clinic, VA Medical Center, Washington, District of Columbia, USA gUniversity of Milano-Bicocca, Milan, Italy Correspondence to Demetrios V. Vlahakos, Renal Unit, Attikon University Hospital, 1 Rimini Street, Haidari, Athens 12462, Greece. Tel: +30 210 583 2346; fax: +30 210 6747480; e-mail: [email protected] Abbreviations: ACEi, angiotensin-converting enzyme inhibitor; ARB, angiotensin receptor blocker; CKD, chronic kidney disease; CRS, cardiorenal syndrome; EPO, erythropoietin; GFR, glomerular filtration rate; HFpEF, heart failure with preserved ejection fraction; HFrEF, heart failure with reduced ejection fraction; RAS, renin-angiotensin system Received 17 May, 2018 Revised 12 January, 2019 Accepted 11 March, 2019 Journal of Hypertension: November 2019 - Volume 37 - Issue 11 - p 2145-2153 doi: 10.1097/HJH.0000000000002111 Buy Metrics Abstract The term ‘cardiorenal syndrome’ (CRS) was introduced to describe problems related to the simultaneous existence of heart and renal insufficiency. The prevalence of anaemia in CRS is high and increases the risk of hospitalizations and death. Renin-angiotensin system (RAS) inhibition is the cornerstone therapy in cardiovascular and renal medicine. As angiotensin II regulates both glomerular filtration rate (GFR) and erythropoiesis, RAS inhibition can further deteriorate renal function and lower hematocrit or cause anaemia in patients with heart failure. The aim of this review is to explore the relationship among CRS, anemia and administration of angiotensin-converting enzyme inhibitor (ACEi) or angiotensin receptor blocker (ARB) and summarize the evidence suggesting that RAS inhibition may be considered an iatrogenic cause of deterioration of CRS with anemia. It should be emphasized however, that RAS inhibition reduces mortality in both groups with and without worsening of renal function, and therefore, no patient with CRS should be denied an ACEi or ARB trial without careful evaluation. Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.