150 ECHO-DERIVED LEFT VENTRICULAR MECHANO-ENERGETIC EFFICACY CHARACTERIZES HYPERTENSIVE PATIENTS WITH IMPAIRED PET-DERIVED MYOCARDIAL BLOOD FLOW
Authors: Lembo Maria , Acampa Wanda , Elena Rao Maria Assunta , Virginia Manzi Maria , Morisco Carmine , Mancusi Costantino , Esposito Giovanni , Cuocolo Alberto , Izzo Raffaele , Trimarco Bruno 
Published: December 2022

Abstract

Background
Chronic left ventricular (LV) pressure overload determines both morphological and functional alterations in the heart and in the vascular system with occurrence of LV hypertrophy, coronary rarefaction and metabolic impairment, predisposing to heart failure. We aim at investigating early cardiac involvement in hypertensive disease by both Positron emission tomography (PET) and echo assessment and possible associations between alterations of PET-derived myocardial blood flow (MBF) and echocardiographic parameters of LV performance including mechano-energetic efficiency indexed for myocardial mass (MEEi), in a population of symptomatic hypertensive patients without flow-limiting epicardial coronary artery disease (CAD).

Methods
The study population included 78 symptomatic hypertensive patients without flow-limiting epicardial CAD. All patients underwent standard echocardiographic assessment, including evaluation of LV MEEi, and PET assessment with evaluation of MBF and MBF/mass ratio at rest and after stress and myocardial flow reserve (MFR).

Results
The study population included 67% males, 55% with dyslipidaemia, 42% with smoking habits and 21% obese. Prevalence of LV hypertrophy was of 43%. Among parameters of LV systolic performance, hyperaemic MBF/mass ratio resulted significantly correlated with LV MEEi (r=0.54, p&lt;0.0001), midwall fractional shortening (r=0.38, p=0.001) but not with LVEF (r=0.10, p=0.47). Similarly, resting MBF/mass ratio resulted to have statistically significant correlations with LV MEEi (r=0.51, p&lt;0.0001), midwall fractional shortening (r=0.29, p=0.01) but not with LVEF (r=0.11, p=0.39). LV MEEi reached the highest correlation coefficient with both resting and stress MBF/mass ratio. On the other hand, the correlation between MEEi and MFR did not reach statistical significance (r=0.11, p=0.33).
In a multiple linear regression analysis, after adjusting for sex, systolic blood pressure, prevalence of LV hypertrophy and therapy with diuretics, the association between LV MEEi and hyperaemic MBF/mass ratio remained significant (beta coefficient =0.40, p=0.007). In a subsequent multivariate model, adjusting for the same confounders, by replacing hyperaemic MBF/mass ratio with resting MBF/mass ratio, LV MEEi and resting MBF/mass ratio continued to be significantly associated (beta coefficient =0.32, p=0.015).

Conclusions
In a population of hypertensive patients without flow-limiting epicardial CAD, an early myocardial impairment possibly related to coronary rarefaction and inadequate angiogenesis contributing to the altered myocardial metabolic demand and efficacy is detectable by both PET and echo-derived LV MEEi. Indeed, an independent association between LV MEEi and both MBF/mass ratio at rest and after stress exists, LV MEEi having the advantage over PET of being easily derived from standard echocardiography and not needing radiation exposure.