Abstract 527: Arterial Stiffness and Coronary Flow Reserve Are Independent Determinants of LV Untwisting in Untreated Patients With Essential Hypertension: A Speckle Tracking Echocardiography Study
Objective: LV utwisting is a novel marker of myocardial relaxation and LV diastolic suction. Arterial stiffness and impaired coronary microcirculation may determine left ventricular (LV) function. We investigated the association of the above parameters with LV twisting and untwisting.
Methods: We studied 60 untreated consecutive patients (mean age: 54±11 years), with newly diagnosed essential hypertension and 30 healthy controls matched for atherosclerotic factors. We measured
Carotid to femoral artery pulse wave velocity (PWV)
Coronary flow reserve (CFR) after adenosine infusion.
Peak Twisting (pTw-deg) and Untwisting (Utw) at mitral valve opening (UtwMVO) and at the end of LV early filling defined as the end of the mitral inflow E wave (UtwE-deg) using speckle tracking imaging.
We calculated the percentage difference between Peak twisting and untwisting at MVO [%difference (pTw- UtwMVO) ] and end of mitral E wave [%difference (pTw-UtwE) ] and the corresponding untwisting rates.
Results: Patients had higher PWV (10.5±1.8 vs 8.2±1.5, p<0.01) and lower CFR, (2.5±0.6 vs 3.2±0.6, p<0.01) than normals. Compared to controls, hypertensives had increased peak twisting (15.7±3.6 vs.13.8±4.3 deg p<0.05) and decreased %difference pTw-UtwMVO (29±8 vs. 38±7%, p<0.05 ) %difference pTw-UtwE 67±9 vs. 73±8%, p<0.05), untwisting rate at MVO (0.34±0.1 vs. 0.55±0.1 deg/sec p<0.05) and end of mitral E wave (0.19±0.1 vs. 0.24±0.1 deg/sec p<0.05)). Increasing PWV and decreasing CFR were related to reduced %difference pTw-UtwMVO (r=−0.48 and r=0.43, p<0.01), %difference pTw-UtwE (r=−0.37, r=0.47, p<0.01), untwisting rate at MVO (r=−0.64 and r=0.43, p<0.01) and end of LV early filling (r=−0.38 and r=0.42, p<0.01). By regression analysis, the above relations remained significant after adjustment for age, sex, BMI, LV mass and blood pressure (p<0.01). By ROC analysis a PWV>10.5 and CFR<2.5 were significant predictors of an untwisting rate at MVO >0.30 %/sec (median of the study population) [AUC=82%, 95% CI: 70 –90% p<0.01 and AUC=71%, 95% CI: 56 – 87% p=0.013 ]
Conclusions: Increased arterial stiffness and abnormal coronary microcirculation are independent determinants of impaired LV untwisting in never-treated patients with essential hypertension.