ISIS-4 Results Confirm ACEI Benefits In MI

The results of the mammoth Fourth International Study of Infarct Survival (ISIS-4) study have now been published in The Lancet (March 18), and will disappoint proponents of two widely accepted treatments for myocardial infarction patients, intravenous magnesium and oral nitrates, but provide confirmation of the value of ACE inhibitors.

The 58,050-patient study found that magnesium had a negative effect on outcome, oral nitrate was safe but provided no benefit, while ACE inhibition achieved a 7% reduction in five-week mortality, which appeared to be maintained at one year.

ISIS-4 comprised patients with suspected acute myocardial infarction and no clear contraindications, who were randomized in a 2x2x2 factorial fashion to three treatment arms: one month of ACE inhibitor treatment (Bristol-Myer's Squibb's Capoten [captopril]) versus matching placebo; one month of oral controlled-release nitrate (Astra's Imdur [isosorbide mononitrate]) versus matching placebo; and 24 hours of intravenous magnesium versus open control.