Midregional proatrial natriuretic peptide (MR-proANP) may be a useful biomarker for predicting cardiac dysfunction and death in hypertrophic cardiomyopathy (HCM), according to study results published in Heart.

In this study, researchers followed 357 patients with HCM for 23 months to compare the prognostic value of MR-proANP and N-terminal probrain natriuretic peptide (NT-proBNP). At inclusion, patients provided medical history and had clinical, electrocardiogram, and echocardiographic evaluation and measurement of MR-proANP and NT-proBNP. Venous blood samples were collected from each patient to measure natriuretic peptides.

At baseline, median maximal wall thickness was 20 mm (interquartile range [IQR], 17-24), and 26% of patients had left ventricular outflow tract obstruction. Median MR-proANP was 107 pmol/L (IQR, 58-184) and median NT-proBNP was 550 pg/mL (IQR, 202-1380).

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At the end of 23 months, an investigator recorded end points for each patient. Results revealed that 32 patients experienced the following end points: death (n=6), hospitalization due to heart failure (n=17), heart transplantation (n=8), and left ventricular assist device implantation (n=1).

NT-proBNP and MR-proANP (P <10⁻⁴) were both strongly associated with the primary end point. Patients who reached the primary end point had higher concentrations of MR-proANP and NT-proBNP than counterparts (228 pmol/L [IQR, 135-341] vs 101 pmol/L [IQR, 55-171] and 2010 pg/mL [IQR, 785-2707] vs 505 pg/mL [IQR, 196-1208] respectively, both P <10⁻⁵).

In a multivariable analysis, researchers determined that the best model for predicting adverse outcome in HCM was New York Heart Association class 1-2 vs 3-4 (hazard ratio [HR], 0.35; 95% CI, 0.16-0.77; P <.01), left ventricular ejection fraction (HR, 0.96; 95% CI, 0.94-0.98; P =.0005) and MR-proANP (HR, 3.77; 95% CI, 2.01-7.08; P <.0001).

This study had several limitations. First, some echocardiographic measurements were not available for all patients or included in the model for prognostic analysis. Second, left ventricular outflow tract obstruction was evaluated only at rest. Third, most patients did not have advanced HCM and had few or no symptoms. 

The study researchers concluded that MR-proANP is strongly related to heart dysfunction and prognosis in HCM, and may be more useful than NT-proBNP at identifying high-risk HCM patients.

Disclosure: Several study authors declared affiliations with the pharmaceutical industry. Please see original reference for a full list of authors’ disclosures.

Reference

Bégué C, Mörner S, Brito D, et al. Mid-regional proatrial natriuretic peptide for predicting prognosis in hypertrophic cardiomyopathy [published online July 26, 2019]. Heart. doi:10.1136/heartjnl-2019-314826