Myocardial mechano-energetic efficiency in primary aldosteronism

Available data indicate that patients with primary aldosteronism have an increased risk of cardiovascular events and cardiovascular risk seems to be, at least in part, independent of blood pressure (BP) values. Patients with primary aldosteronism have a greater prevalence of left ventricular (LV) hypertrophy and subtle alterations of ventricular function, which might contribute to the increase in cardiovascular risk. Recently, a noninvasive approach for the estimation of LV mechanical efficiency, obtained by echocardiography has been proposed.

To evaluate the determinants of myocardial mechanoenergetic efficiency index (MEEi), in a large group of patients with primary aldosteronism (n = 99) and in a control group of essential hypertensive patients (n = 99) matched for age, sex and BP values.

No differences between groups for age, sex, BMI, BP values, glucose, lipid profile and renal function were observed. LV mass index was greater in primary aldosteronism vs. essential hypertensive patients (46.0 ± 16.7 vs. 36.9 ± 8.6 g/m2, P < 0.001); also relative wall thickness was greater in primary aldosteronism (0.36 ± 0.1 vs. 0.32 ± 0.4, P < 0.001). Left atrial dimensions were significantly greater in primary aldosteronism. Ejection fraction was not different between groups, while endocardial and midwall fractional shortening were lower in primary aldosteronism vs. essential hypertensive patients (40 ± 7 vs. 43 ± 6, and 18 ± 3 vs. 21 ± 2, both P < 0.01). MEEi was lower in primary aldosteronism vs. essential hypertensive patients (0.44 ± 0.14 vs. 0.52 ± 0.10 ml/s per g, P < 0.01). A negative correlation was observed between MEEi and aldosterone levels (r = -0.203, P < 0.05) and aldosterone : renin ratio (P = -0.172, P < 0.05); the correlation remained significant after adjustment for possible confounders.

In patients with primary aldosteronism myocardial MEEi is lower as compared with essential hypertensive patients. A reduced MEEi may reflect an impairment of production and utilization of energy in the myocardium, which could lead to the occurrence of cardiovascular complications and therefore these findings may contribute to explain the increased risk of cardiovascular events in patients with primary aldosteronism.