Results from a prospective study using data from the National Heart, Lung, and Blood Institute's Hypertrophic Cardiomyopathy (HCM) Registry provide important evidence in support of incorporating cardiac magnetic resonance (CMR) imaging and NT-proBNP into the evaluation of risk in patients with HCM.

The study, published in JAMA, uses data from approximately 2,700 patients with low- to intermediate-risk HCM enrolled in the HCM Registry from 44 sites in North America and Europe. The average patient age was 50 years, 71% were male and 16% were from underrepresented racial and minority groups. All patients completed a health history questionnaire and underwent contrast-enhanced CMR, as well as blood sampling for biomarkers and genotyping. Average follow-up was about 7 years.

Results showed a a total of 117 primary composite events involving HCM-related death, nonfatal sustained ventricular arrhythmias requiring cardioversion or defibrillation, and left ventricular (LV) assist device implant or heart transplant occurred among 104 patients (3.9%) and were predicted by CMR imaging of LV structure. Additionally, 77 sudden cardiac deaths and ventricular arrhythmias events occurred in 69 patients (2.3%) and were "predicted by LV structure and function and NT-proBNP," researchers said.

According to lead investigator, Christopher M. Kramer, MD, MACC, the study is the largest of its kind to involve imaging and blood tests to identify patients with HCM who are at higher risk of adverse outcomes. "This is an important next step to do a better job of identifying HCM patients at high risk," he said. "This adds to presently used risk markers derived from the patient's and their family's prior history."

Kramer also noted that the study results will help clinicians better determine which patients could best benefit from cardioverter-defibrillator devices and potentially spare those at lower risk from unneeded implantations. He and colleagues say, "future work will include development of a risk score as well as external validation from independent databases with similar comprehensive measures."