ACE inhibitor benefit in ACS may depend on NT-proBNP elevation
MedWire News: Treating acute coronary syndrome (ACS) patients with an ACE inhibitor is beneficial only among those with the most marked elevations in plasma N-terminal pro-B-type natriuretic peptide (NT-proBNP), an observational study suggests.
The finding held true after taking into account likelihood of ACE inhibitor treatment, and in patients with non-ST-segment elevation myocardial infartion (NSTEMI) as well as STEMI patients.
Iain Squire and colleagues from University of Leicester, UK, compared rates of major adverse cardiac events (MACE) according to ACE inhibitor prescription and plasma NT-proBNP levels among 1725 patients with ACS admitted to their coronary care unit between March 2000 and July 2007. Prescription of an angiotensin receptor blocker (ARB) was considered equivalent to that of an ACE inhibitor.
They report in the journal Heart that 73.4% of patients were prescribed an ACE inhibitor or ARB during the index admission, and 73.6% experienced a MACE during follow-up lasting a median of 528 days.
NT-proBNP level was strongly associated with MACE whether considered as a continuous variable or divided by quartile.
Cox proportional hazards modeling and Kaplan Meier survival analysis indicated that the survival benefit from ACE inhibitor or ARB treatment was confined to those patients with NT-proBNP levels in the top quartile. Among these patients, ACE inhibitor or ARB treatment was associated with a hazard ratio (HR) of 0.597 after multivariable adjustment (p=0.001).
There was no statistically significant benefit of ACE inhibitor or ARB use in any other quartile (HRs of 1.2 in the lowest and 1.3 in the second lowest quartiles, and 0.9 in the second highest).
Survival analysis corrected for quintile of propensity scores for probability of ACE inhibitor or ARB treatment confirmed the interaction between ACE inhibitor prescription and NT-proBNP level. Among patients with NT-proBNP in the top quartile, ACE inhibitor or ARB treatment remained associated with approximately 40% reduction in risk for MACE (HR=0.574).
“Plasma NT-proBNP may provide a useful indicator of the appropriateness of individual prescription of ACE inhibitor of ARB treatment across the spectrum of ACS,” the team concludes.
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By Caroline Price