Heart Failure: ACEi/ARB/ARNI Prescribing

Heart failure with reduced ejection fraction (HFrEF) is heart failure symptoms with a left ventricular ejection fraction (LVEF) of 40% or less. A falling cardiac output activates the renin-angiotensin-aldosterone system (RAAS). Angiotensin-converting enzyme (ACE) converts angiotensin I to angiotensin II, which constricts vessels and stimulates aldosterone secretion from the adrenal cortex. Less aldosterone means less potassium excretion, which is why every drug that blocks this system can raise serum potassium. Three drug classes act on the same system, and each has a signature risk that dictates what the NP monitors: - ACE inhibitors (ramipril, enalapril, lisinopril, perindopril, trandolapril) lower angiotensin II and aldosterone. ACE also breaks down bradykinin, so bradykinin rises. That is the likely basis of ACE-inhibitor cough and angioedema. The CCS guideline describes intolerance from a bothersome cough (approximately 10%) or angioedema (less than 1%). Cough is a bradykinin effect, not an allergy. - Angiotensin receptor blockers (ARBs: candesartan, valsartan, losartan) block the angiotensin II type 1 (AT1) receptor directly. - The angiotensin receptor-neprilysin inhibitor (ARNI) sacubitril-valsartan combines the ARB valsartan with sacubitril. Sacubitril is a prodrug whose...