Myocardial ultrasound tissue characterization of patients with primary aldosteronism

Abstract

Primary aldosteronism (PA), an underdiagnosed cause of hypertension, is associated with more significant cardiac remodeling and myocardial fibrosis than is essential hypertension (EH). The aim of this study was to validate myocardial fibrosis and to evaluate factors associated with the degree of myocardial fibrosis in patients with PA. We prospectively analyzed 62 patients with PA (including 46 patients with aldosterone-producing adenoma and 16 with bilateral hyperplasia) between October 2006 and October 2010, and we enrolled 17 patients with EH as the control group. Echocardiography, including ultrasonic tissue characterization using cyclic variation of integrated backscatter (CVIBS), was performed in individuals in both groups. Among patients with PA, the diastolic blood pressures and plasma aldosterone concentrations were significantly higher than those of patients with EH. Moreover, the serum potassium levels and the plasma renin activities were significantly lower in patients with EH. As observed by echocardiography, patients with PA had greater interventricular septal thickness, greater left ventricular posterior wall thickness, and higher left ventricular mass indexes than did patients with EH. Patients with PA had significantly lower CVIBS values than patients with EH (7.1 ± 2.2 vs. 8.7 ± 1.5 dB; p = .005). In a correlation study that corrected for various clinical parameters, only log-transformed plasma renin activity values correlated significantly with CVIBS values. Ultrasonic tissue characterization with CVIBS is a useful tool for determining the extent of myocardial fibrosis. Patients with PA exhibit a more severe degree of myocardial fibrosis, as detected by CVIBS, than do patients with EH. Moreover, the severity of fibrosis, as detected by CVIBS, correlates with log-transformed plasma renin activity values.