The importance of vasodilator stress echocardiography in predicting all-cause mortality and acute heart failure in hypertrophic cardiomyopathy

Abstract

Abstract Background Reduced coronary flow velocity reserve (CFVR) in the left anterior descending coronary artery (LAD) during vasodilator stress echocardiography (VSE) is a marker of poor outcome and is associated with higher baseline coronary flow velocity (CFV) in hypertrophic cardiomyopathy (HCM). However, whether resting CFV has additive predictive value to CFVR during VSE in HCM is unknown. Aim To assess the prognostic value of baseline CFV and CFVR during VSE in HCM. Methods 325 adult HCM patients (age=52+15 years, 147 [45%] females) with preserved left ventricular function and no known coronary artery disease who underwent VSE in 6 certified centers between 1999 and 2021 were prospectively analyzed. VSE modality was adenosine (0.14 mg/kg/min in 2', n=232) or dipyridamole (0.84 mg/kg in 6', n=93). CFVR in the LAD was assessed by transthoracic (n=306) or transoesophageal (n=19) echocardiography. Patients were followed for a median of 67 months (IQ range 31-103 months), the primary endpoint was a composite of all-cause mortality and acute heart failure (HF). Results Receiver operating characteristic analysis was used to determine the best cut-off value of CFV (>31 cm/s, elevated) and CFVR (≤2.0, reduced) to predict the primary endpoint. Patients with reduced CFVR had more frequently elevated baseline CFV (75% vs 49%, p<0.001). Elevated resting CFV was a predictor of composite endpoint at univariable (HR 2.04, 95% CI 11.05-3.97, p=0.035) but not at multivariable analysis. A reduced CFVR was an independent predictor of all-cause mortality (HR 5.50, 95% CI 1.94-15.59, p=0.001), acute HF (HR 5.80, 95% CI 1.60-21.00, p=0.007), and the composite end-point (HR 4.95, 95% CI 2.39-10.25, p<0.001). The 5-year event rate was 6-fold higher in patients with reduced CFVR compared to patients with preserved CFVR (19% vs 3%, p<0.001), with no additional impact of resting CFV (see Figure). Conclusion LAD CFVR ≤2.0 during VSE is a strong and independent predictor of all-cause mortality and acute HF in HCM. Elevated resting CFV is more frequent in patients with reduced CFVR, but has no independent prognostic value when CFVR is considered.Kaplan-Meier event-free survival curves