Role of cardiovascular magnetic resonance imaging and cardiopulmonary exercise test in predicting composite clinical outcomes in patients with hypertrophic cardiomyopathy

We aimed to evaluate the additive value of cardiovascular magnetic resonance imaging (CMR) and cardiopulmonary exercise test (CPET) to predict clinical outcomes in patients with HCM. We enrolled 373 patients with HCM and normal left ventricular systolic function who underwent CPET and CMR. The primary outcome was a clinical composite of all-cause death, cardiac transplantation, stroke, heart failure requiring hospitalization and defibrillator implantation. During a follow-up of 70.70 ± 30.74 months, there were 84 composite clinical events. Peak oxygen consumption during CPET was significantly lower (18.51±13.25 vs. 24.59±13.28 mL/kg/min, p < 0.001) and abnormal hemodynamic response to exercise was more frequently detected (41.7 vs. 20.8%, p<0.001) in the group with composite clinical events. The extent of late gadolinium enhancement was larger in the event group (15.39±10.53 vs. 11.97±9.53%LV, p<0.001). Selective parameters were added stepwise to conventional clinical parameters; the final model, where CPET and CMR parameters were added, was verified to have the highest increment value for clinical outcome prediction (p<0.001). This study demonstrated that CPET and CMR findings may be important clinical tools for risk stratification in HCM. Exercise capacity was an independent predictor of composite outcomes in patients with HCM, with incremental value as a risk factor when added to the alleged parameters. These findings could help physicians monitor and manage patients with HCM in the real clinical field.