Acute myocardial infarction (MI) patients with elevated blood concentrations of natriuretic peptides (NPs) are at increased risk of in-hospital mortality, according to the results of a new observational study published April 29 in Clinical Chemistry.

The finding suggests that measurements of NPs could significantly improve the risk discrimination for in-hospital mortality beyond a validated clinical risk score, especially for acute MI patients who would otherwise be considered at low risk for in-hospital mortality.

Using data from the ACTION Registry® — GWTG™, the authors looked at 41,683 patients with non-STEMI and 27,860 patients with STEMI. Results showed a stepwise increase in the risk of in-hospital mortality with increasing B-type natriuretic peptide (BNP) quartiles for both NSTEMI and STEMI patients. When BNP was added to the ACTION Registry — GWTG clinical model, the C statistic was improved from 0.796 to 0.807 in NSTEMI patients (p < 0.001) and from 0.848 to 0.855 in STEMI patients (p = 0.003).

A BNP ≥80 ng/L was identified in 78 percent of patients with NSTEMI and 60 percent of STEMI patients. NSTEMI and STEMI patients with greater comorbidities, delayed presentation, heart failure, and shock on admission had higher concentrations of BNP. Heart failure on admission was present in 69 percent of NSTEMI patients and 43 percent of STEMI patients.

The authors also found that the relationship between NPs and mortality was similar in patients without a history of heart failure or cardiogenic shock on presentation at the hospital and in patients with preserved left-ventricular function, patients who would typically be considered at lower risk of in-hospital mortality.

NPs are established serum markers in the diagnostic and prognostic assessment of patients with heart failure and left-ventricular dysfunction, and they have been proposed as markers in the assessment of patients with acute coronary syndrome. However, until this study was done, NPs had yet to be evaluated for risk stratification in a large cohort of patients with MI. Moving forward, the authors note that "specific treatment strategies targeted toward patients with increased concentrations of NPs should be a focus of future prospective studies."

Keywords: Shock, Cardiogenic, Acute Coronary Syndrome, Hospital Mortality, Biomarkers, Heart Failure, Comorbidity, Ventricular Dysfunction, Left, Natriuretic Peptide, Brain