Prognostic value of two-dimensional echocardiography and N-terminal proatrial natriuretic peptide following an acute myocardial infarction. Assessment of baseline values (2-7 days) and changes at 3 months in patients with a preserved systolic function

Abstract

Aims: The purpose of this prospective, observational study was to evaluate the relationship of left ventricular volumes, systolic function and plasma N-terminal proatrial natriuretic peptide (Nt-proANP) to cardiac morbidity and mortality in post-myocardial infarction patients with left ventricular ejection fraction > or =40%.

Methods and results: Two-dimensional echocardiographic recordings and Nt-proANP measurements were obtained in 834 patients who survived acute myocardial infarction. Patients were examined at 2-7 days and 3 months after the index infarction and followed up for 24 months. All measurements of left ventricular volumes, ejection fraction and Nt-proANP were performed in core laboratories. During follow-up 102 patients sustained one or more incidents of the combined primary end-point: cardiac death (n=11), recurrent infarction (n=55) or heart failure requiring hospitalization or treatment with an ACE inhibitor and a diuretic (n=52). Using Cox proportional hazards model, baseline Nt-proANP predicted these events (chi-square 25.3, P<0.0001), while baseline echo volumes and ejection fraction did not. During the subsequent 3-24 month period, 51 patients suffered a primary end-point: cardiac death (n=9), recurrent infarction (n=29), heart failure (n=21). An increase in left ventricular end-systolic volume was the strongest predictor for adverse events (chi-square 19.1, P<0.0001), especially for heart failure. Individual changes in Nt-proANP did not predict cardiac events, whereas both echocardiographic variables and Nt-proANP measured at 3 months had a prognostic impact on subsequent cardiac events (3-24 months).

Conclusions: In post-myocardial infarction patients with preserved left ventricular function (left ventricular ejection fraction > or =40%) baseline Nt-proANP, but not echocardiographic left ventricular volumes predicted adverse cardiac events. Early changes in left ventricular volumes and ejection fraction from baseline to 3 months had a further prognostic impact on subsequent events (3-24 months).