Characterization of impaired left ventricular mitral filling in HCM: A 4D-flow CMR study

Introduction

Diastolic dysfunction is common and contributes to many clinical manifestations in hypertrophic cardiomyopathy (HCM). 4-dimensionnal (4D) flow cardiac magnetic resonance (CMR) sequence can assess left ventricular mitral filling. The purpose of this study was to determine if the peak early filling rate normalized to the filling volume (PEFR/FV), estimated from 4D-flow sequence can accurately assess impaired left ventricular mitral filling and predict clinical outcomes.

Method

This monocentric study included 44 HCM patients from a prospective HCM register and 44 healthy volunteers, who all underwent CMR with 4D-Flow sequence. Median follow-up time of HCM cohort patients was 2.3 years (interquartile range: 1.7 to 3.3 years). The predefined primary endpoint was a composite criteria that included syncope, onset of atrial fibrillation, admission for congestive heart failure with administration of diuretics, decision to perform septal reduction therapy due to persistent symptomatic obstruction, stroke, ventricular tachycardia or fibrillation and cardiac death.

Results

PEFR/FV was significantly lower in HCM cohort compared to healthy volunteers (P < 0.001). PFR/FV significantly correlated with BNP (r = −0.31, P < 0.001) and with E/E’ ratio (r = −0.56, p < 0.001). PEFR/FV according to NYHA status in HCM cohort was statistically different (P = 0.001). Primary endpoint occurred in 14 patients (32%). In univariate and bivariate adjusted cox-model analysis PEFR/FV < 2.61 s -1 was significantly associated with primary endpoint with Hazard Ratio ranging from [HR = 9.46 (95% CI 2.61–45.17, P < 0.001) to 15.21 (95%CI 3.51–80.22, P < 0.001)] according to succesive bivariate models.

Conclusion

4D-Flow can accurately assess left ventricular mitral filling with a good predictive value of clinical outcomes in HCM patients. Relation of PEFR/FV calculated with 4D flow in HCM.