Abstract 3902: Abnormal Ventriculo-Vascular Coupling is Associated With Abnormal Aortic Stiffness, but Not With Abnormal Myocardial Strain or Torsion in Patients With Hypertrophic Cardiomyopathy: Novel Insights From Cardiac Magnetic Resonance Imaging
Introduction Ventriculo-vascular coupling (VVC) is an important index for left ventricular(LV) performance. Abnormal VVC has been demonstrated in patients with hypertension and diastolic heart failure. The relationship of VVC with the individual component of LV and aortic stiffness has not been previously established.
Hypothesis We sought to assess the relationship between abnormal VVC and
LV systolic and diastolic performance (assessed by circumferential strain-Ecc, torsion, and untwist) and
aortic stiffness (assessed by aortic pulse wave velocity-PWV) in patients with hypertrophic cardiomyopathy (HCM).
Methods Cardiac MRI was performed in 77 HCM patients. The VVC index was derived by effective arterial elastance (end-systolic pressure/stroke volume) divided by effective LV end-systolic elastance (end-systolic pressure/end-systolic volume). Myocardial tagging was applied in basal, mid, and apical slices to quantify circumferential strain, torsion, and diastolic untwist, while velocity-encoded MRI was performed perpendicular to the long axis of the mid ascending and descending thoracic aorta. The PWV was calculated as the distance difference divided by the time delay of wave velocity between 2 sites.
Results Mean VVC was 0.82±0.27. Abnormal VVC, defined as <0.6 or >1.2, was found in 30% of HCM patients. Only PWV was significantly enhanced in patients with abnormal VVC, whereas other myocardial strain, torsion, and untwist indices were not significantly associated with abnormal VVC.
Conclusions This is the first to demonstrate the relationship of increased PWV to the abnormal VVC using the comprehensive roles of MRI. Enhanced PWV may contribute to worsening ventriculo-vascular interaction, or in the other hand, impaired VVC may potentiate aortic stiffness. Abnormal PWV may become one of the surveillance strategies in HCM, provided an additional potential role of MRI beyond the fibrosis assessment.