Relationships between changes in left ventricular mass and in clinic and ambulatory blood pressure in response to antihypertensive therapy

Abstract
To analyse the relationships between changes in left ventricular mass in response to 6-month antihypertensive therapy and changes in conventional and automated measurements of clinic blood pressure, average 24 h ambulatory blood pressure and daytime and night-time blood pressures. After a placebo run-in period, patients with essential hypertension (World Health Organization stages I–II) were treated for 6 months with one or a combination of two first-line antihypertensive drugs. Investigations included echocardiography, conventional and automated clinic blood pressure measurements and ambulatory blood pressure monitoring. Daytime and night-time blood pressures were assessed according to two clock-time-dependent and two clock-time-independent methods, with a wide and a narrow approach for each technique. Fifty-four patients completed the 6-month treatment period. Left ventricular mass, adjusted for sex and body size, was correlated significantly to systolic and diastolic clinic blood pressures, both before (r = 0.57 and r = 0.48, P < 0.001) and during antihypertensive therapy (r = 0.43, P < 0.001 and r = 0.27, P < 0.05). Changes in left ventricular mass were significantly related to changes in blood pressure. The correlation coefficients amounted to 0.39 (P < 0.01) and 0.40 (P < 0.01) for the conventional and automated measurements of clinic systolic blood pressures, respectively, and to 0.45 (P < 0.001) for the average 24 h systolic blood pressure; these r values were 0.27 (NS), 0.20 (NS) and 0.43 (P < 0.01), respectively, for the diastolic blood pressure. The average 24 h blood pressure added 7.4% (P < 0.05) and 6.2% (P = 0.06) to the variance of the changes in mass explained in terms of the conventional and the automated measurements of clinic systolic blood pressures, respectively, and 11.2% (P < 0.05) and 14.5% (P < 0.01) for the diastolic blood pressures. The changes in daytime and night-time blood pressures predicted the changes in left ventricular mass significantly (P < 0.01) and to a similar extent, irrespective of the analytical method. The treatment-induced changes in left ventricular mass were significantly related to the changes in clinic, 24 h, daytime and night-time blood pressures; the changes in 24 h ambulatory blood pressure add to the variance of the changes in left ventricular mass explained in terms of clinic blood pressure data.