A non-invasive left ventricular pressure-strain loop study on myocardial work in primary aldosteronism

Abstract

We investigated the myocardial work derived from left ventricular pressure-strain loop in patients with primary aldosteronism or primary hypertension. We enrolled 50 patients with primary aldosteronism, 50 age- and sex-matched patients with primary hypertension, and 25 normotensive control subjects. We performed transthoracic echocardiography and speckle-tracking echocardiography-based left ventricular pressure-strain loop analysis to evaluate cardiac structure and function. Patients with primary aldosteronism and those with primary hypertension had similar clinic and ambulatory blood pressures, except that the former had a significantly (P = 0.03) higher nighttime systolic blood pressure. All subjects had normal left ventricular ejection fraction (66.4 ± 4.7%). Patients with primary aldosteronism had a greater left ventricular mass index than those with primary hypertension and the normal controls (111.0 ± 21.6 g/m2 versus 95.7 ± 17.7 and 77.9 ± 13.5 g/m2, respectively, P < 0.001). The global myocardial work index (GWI, 2336 ± 333, 2366 ± 288, and 2292 ± 249 mmHg%, respectively), and global constructive work (GCW, 2494 ± 325, 2524 ± 301, and 2391 ± 193 mmHg%, respectively), were comparable in the three groups (P ≥ 0.18). However, the global work efficiency (GWE) differed significantly (P < 0.001), being lowest in primary aldosteronism (91.1 ± 2.7%), intermediate in primary hypertension (93.5 ± 2.5%) and highest in controls (95.3 ± 1.5%). The opposite was true for the global wasted work (GWW) (205.6 ± 74.6, 142.0 ± 56.4 and 99.4 ± 33.7 mmHg%, respectively, P < 0.001). GWE was significantly correlated with the logarithmically transformed plasma concentration and the urinary excretion of aldosterone in patients with primary aldosteronism or primary hypertension (r = -0.43 for both, P < 0.001). The associations remained statistically significant (P ≤ 0.04) after further adjustment for several factors, including left ventricular mass index and clinic or nighttime blood pressure. In conclusion, GWE decreased and GWW increased in primary hypertension and further in primary aldosteronism, probably because of the adrenal aldosterone hypersecretion and the left ventricular mass index increase, while GWI and GCW were similar, indicating that similar and normalized total myocardial work might be a compensation in hypertension at the expense of work efficiency.