[ACE inhibitors and angiotensin II receptor antagonists in acute coronary syndrome].
Angiotensin II (AT II) is a final product of the renin-anglotensin-aldosterone system (RAS) and presents one of the most influential factors in the pathogenesis of atherosclerosis, acute coronary syndrome, myocardial dysfunction and heart failure. ACE-inhibitors (ACEI), beside beta adrenergic blockers, are a cornerstone of the current chronic heart failure (CHF) treatment. Evidence based medicine has not yet proved any significant beneficial effects of ACEI in patients with unstable angina pectoris (UAP), although according to the SoLVD study testing the possible effects of ACEI in patients with significant left ventricular dysfunction and/or CHF, there was a significant hospitalization rate reduction as well as less transformation of UAP to myocardial infarction in patients treated with ACEI. In the GISSI 3, ISIS 4 and CCS studies, ACEI was given within the first 24 hours and continued for 4-6 weeks. According to pooled results, ACE inhibitor could save 11/1000 patients with ST-elevation myocardial infarction (STEMI) and only 1/1000 patients with non ST-elevation myocardial infarction (NSTEMI). In the SAVE, AIRE and TRACE studies, ACEI was started later, i.e. 3-16 days after acute myocardial infarction and continued for several years. ACEI therapy resulted in a significantly lower mortality during the first year, and an even 20% relative reduction in the total mortality during the 4-year follow up. The effects of ACEI were even more prominent in more severe myocardial dysfunction, as it was well known that they could slow or stop unfavorable myocardial remodeling. Conclusively, ACEI should be given as early as possible to all patients with acute myocardial infarction, if no contraindications. The HOPE study showed efficacy of ACEI in the primary prevention of ischemic heart disease in high risk individuals, and the EUROPA study showed a favorable effect of ACEI in the secondary prevention of ischemic heart disease in low risk patients. According to these findings, ACEI should be given permenantly following myocardial infarction. These findings suggest the need of a permanent treatment with ACEI in patients having sustaned myocardial infarction. Angiotensin-1 receptor antagonists (AT-1 antagonists) are a newer generation of neurohormonal antagonists, which block the effects of AT II produced not only through a classic, ACE-dependent pathway but also via alternative pathways (non ACE-dependent) and selectively bind to AT-1 receptors for AT II. Therefore, they have some theoretical advances in comparison with ACEI. There are 2 relevant studies elucidating their possible role in treating patients with or post-myocardial infarction. The OPTIMAAL study did not prove losartan to be better than an ACEI (captopril), while the VALIANT study showed that the effects of valsartan vs. captopril were statistically nonsignificantly different. Furthermore, there is no sense to combine AT-1 antagonist and ACEI, while a combination of AT-1 antagonist and a beta blocker is justified. In other words, AT-1 antagonist (the class effect is disputable) should be given to patients with acute myocardial infarction or to post-myocardial infarction patients who cannot take ACEI.
Milicić
Davor
D
Odjel za koronarnu intenzivnu skrb i aritmije, Klinika za bolesti srca i krvnih zila, Klinicki bolnicki centar Zagreb, Kispatićeva ul. 12 10000 Zagreb, Hrvatska.
D000789:Angina, Unstable / Q000188:drug therapy*; D057911:Angiotensin Receptor Antagonists; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000627:therapeutic use*; D006801:Humans; D009203:Myocardial Infarction / Q000188:drug therapy*
D057911:Angiotensin Receptor Antagonists; D000806:Angiotensin-Converting Enzyme Inhibitors