Unstable angina / non ST elevation myocardial infarction inhibitors of RAS


 * Associate Editors-In-Chief: ; Varun Kumar, M.B.B.S.; Lakshmi Gopalakrishnan, M.B.B.S.; Smita Kohli, M.D.;

Overview
Inhibitors of Renin-Angiotensin-Aldosterone axis include:
 * angiotensin converting enzyme inhibitors (ACEI) (e.g., ramipril, captopril),
 * angiotensin receptor blockers, and
 * aldosterone antagonists.

Mechanism of Benefit

 * ACE inhibitors is amongst the class of medications which have been shown to reduce mortality in patients with MI, recent MI and left ventricular dysfunction, and high risk chronic CAD with normal left ventricular function.
 * In patients who cannot tolerate ACE inhibitors, angiotensin II receptor blockers can be used.

Clinical Trial Data
HOPE trial was a landmark study in evaluating the role of ramipril(an ACE inhibitor) in a broad category of high risk patients. In this randomized, placebo controlled trial involving 9297 high risk patients, Ramipril was shown to significantly reduce the rates of death, myocardial infarction, and stroke in a broad range of high-risk patients who are not known to have a low ejection fraction or heart failure.

==ACC / AHA Guidelines (DO NOT EDIT) ==

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Class I
1. An Angiotensin Converting Enzyme inhibitor (ACE) should be administered orally within the first 24 h to Unstable angina / NSTEMI patients with pulmonary congestion or LV ejection fraction (LVEF) ≤40%, in the absence of hypotension (systolic blood pressure <100 mmHg or <30 mmHg below baseline) or known contraindications to that class of medications. (Level of Evidence: A)

2. An angiotensin receptor blocker should be administered to Unstable angina / NSTEMI patients who are intolerant of ACE inhibitors and have either clinical or radiological signs of heart failure or LVEF ≤40%. (Level of Evidence: A)

Class IIa
1. An ACE inhibitor administered orally within the first 24 h of Unstable angina / NSTEMI can be useful in patients without pulmonary congestion or LVEF ≤40% in the absence of hypotension (systolic blood pressure <100 mm Hg or less than 30 mm Hg below baseline) or known contraindications to that class of medications. (Level of Evidence: B)

Class III
1. An intravenous ACE inhibitor should not be given to patients within the first 24 h of Unstable angina / NSTEMI because of the increased risk of hypotension. (A possible exception may be patients with refractory hypertension.) (Level of Evidence: B)}}