Prospective study of ambulatory monitoring and echocardiography in borderline hypertension.

This study was done to evaluate prospectively whether ambulatory blood pressure recordings (AMB) (Spacelabs) would more accurately predict increases in left ventricular mass (LVMI) than did blood pressures measured by a nurse in the absence of a physician, using a random zero sphygmomanometer (RZ) and an automated oscillometric digital device (BPI). One hundred patients being followed by their family physician with a diagnosis of borderline hypertension with at least two office diastolic readings of 90-100 mmHg were studied at baseline and every six months for two years with RZ, BPI, and AMB; echocardiography was repeated annually. Over sixty percent of the patients were normotensive in the research unit by AMB, BPI, and RZ at entry. At entry 24% of patients had increased LVMI greater than 110 g/m2 (left ventricular enlargement, LVE) and at 2 years 32% had LVE. Stepwise linear regression was used to determine which measurement was most predictive of LVE at two years. It showed that the most predictive were baseline echo LVMI and BPI systolic pressure. These two variables predicted 45% of the risk with no other variables contributing significantly. However, when BPI was removed, AMB systolic pressure contributed significantly, though the strength of prediction was reduced to 40%. In a subset of 40 patients who underwent mental stress with mental arithmetic and mirror tracing, the magnitude of systolic pressure elevation during mental stress correlated significantly with LVE over 2 years (R = 0.54, p less than 0.001).