P1827 Impact of coronary microcirculatory dysfunction in the impairment of left ventricular deformation parameters by 4D echocardiographic techniques in hypertrophic cardiomyopathy patients

Background Coronary microvascular dysfunction has been described as an important pathophysiologic feature in hypertrophic cardiomyopathy (HCM). Objective To analyse the impact of coronary microcirculatory dysfunction on left ventricular (LV) deformation parameters obtained by 4D echocardiography in HCM. Methods HCM patients (P) prospectively underwent dedicated transthoracic echocardiogram for microcirculation study. The evaluation of coronary flow velocity reserve (CFVR) was performed in apical three chambers view for the left anterior descending (LAD) artery and in an apical two chambers view for the posterior descending (PD) artery. Diastolic coronary flow velocity (CFV) was measured at basal conditions and during hyperaemia, induced with adenosine perfusion (0.14 mg/kg/min intravenously, during 2 minutes). Absolute CFVR was calculated as the ratio of hyperaemic to basal peak diastolic flow velocities. By 4D TTE (GE E95 equipment) LV global longitudinal strain (GLS), global circumferential stain, global radial strain, area strain, twist and torsion were analysed. Results 23 P were enrolled (57% male, mean age 57.9 ± 13.7 years). Asymmetric septal hypertrophy was verified in 70% of patients, with maximal wall thickness of 21.6 ± 4.3mm. Obstructive HCM was documented in 35% of patients. CFV was successfully measured in the LAD in all patients, but only in 70% of patients in the PD due to technical issues related to poor acoustic window and anatomical constraints. 78% of P (n = 18) presented CFVR At baseline conditions, 4D GLS < -8% was associated with lower LAD flow (34.3 ± 8.3 vs 42.7 ± 9.7cm/s; p = 0.037), trend to lower PD flow (35.3 ± 17.8 vs 49.9 ±18.4 cm/s; p = 0.066). 4D GLS < -8% P presented higher CFVR PD (2.0 ± 0.8 vs 1.1 ± 0.2; p = 0.009), with no significant difference in CFVR LAD. Global circumferential stain 4deg presented higher CFV PD at baseline (49.6 ± 16.5 vs 33,8 ± 12.9 cm/s; p = 0.039) and during hyperemia (68.0 ± 12.2 vs 52.9 ± 12.1cm/s; p = 0.032). Conclusion HCM P with greater impairment in LV deformation parameters by 4D echocardiography presented increased basal diastolic CFV, which can be explained by increased coronary vascular resistance and a higher oxygen demand at baseline conditions. Worse LV performance was also associated with decreased CFVR, mainly in PD.