Preliminary Exploration of Quantitative Stress Myocardial Contrast Echocardiography for Risk Stratification in...

Hypertrophic cardiomyopathy (HCM) is an autosomal dominant genetic cardiovascular disease caused by mutations in genes encoding sarcomeric proteins. Positron emission tomography (PET) has demonstrated prognostic value in assessing myocardial perfusion; however, the clinical utility of PET is limited by radiation exposure and cost. Myocardial contrast echocardiography (MCE) is a radiation-free, widely available imaging modality that shows promise for assessing microcirculatory function; however, the ability of MCE to predict long-term cardiovascular events in HCM remains unclear.

This study recruited 142 patients with HCM and 80 healthy controls from the Sichuan Provincial People's Hospital. All participants underwent exercise-stress MCE to quantify myocardial perfusion using wash-in slope (WIS) and perfusion intensity (PI). Obstructive coronary artery disease was excluded by coronary computed tomography or invasive angiography. A 5-year follow-up was conducted for patients with HCM to monitor adverse cardiovascular events. Subgroup analyses were performed according to clinical event status, left ventricular outflow tract pressure gradient (LVOT-PG), and genetic classification.

The event-positive group showed significantly reduced resting and peak WIS and peak PI, along with complete loss of both WIS and PI reserves. Compared with the variant of uncertain significance (VUS) group, the genetic risk group had significantly lower resting and peak WIS and PI, with a significantly lower WIS reserve (ΔWIS) but comparable PI reserve (ΔPI). Among the resting obstruction, latent obstruction, and non-obstruction subgroups, WIS differed significantly, with the resting obstruction subgroup exhibiting the lowest WIS values and complete loss of both WIS and PI reserves. Resting and peak WIS were strongly and inversely correlated with adverse events. Receiver operating characteristic (ROC) analysis demonstrated that both resting and peak WIS had favorable predictive performance for adverse events.

This preliminary, single-center, hypothesis-generating study suggests that WIS derived from exercise-stress MCE may be a useful marker for risk stratification in HCM; however, larger, multicenter studies are needed to confirm these findings.