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Although ambulatory blood pressure (bp) recordings can be useful in selected patients for diagnosing hypertension and assessing the effects of treatment, there is little evidence that they are better than carefully done clinic BPs. For this reason, definitive recommendations regarding the use of ambulatory BP recordings in the management of hypertension are lacking. Thus, data from the Study on Ambulatory Monitoring of Blood Pressure and Lisinopril Evaluation (SAMPLE) are of interest. In 206 patients with essential hypertension and left ventricular hypertrophy (LVH), ambulatory BP and echocardiography were compared before and after 12 months of drug treatment. Clinic and home BPs were also recorded. Treatment reduced all BP measurements and LV mass (158 to 133 g/m2; P < 0.01). The reduction in LV mass correlated best with ambulatory BP reductions but not with the reduction in clinic or home BP. On entry, clinic BP was greater than home BP, which was greater than average daytime BP (ambulatory monitor), which was greater than average night BP. These differences persisted with treatment but were of lesser magnitude. Mancia et al conclude that this study is the first longitudinally controlled proof that ambulatory BP measurements may be superior to clinic BPs.
Of interest, the relationship between LV mass reductions and ambulatory BP reduction was similar for both systolic and diastolic BP and also for average daytime and average night BP. Also intriguing is that in this study, home BP was more similar to clinic BP than average ambulatory BP. Finally, since LVH is associated with higher morbidity and mortality in hypertensive patients, it can be used as a surrogate end point in studies. Perhaps ambulatory BP could serve a similar role. (Dr. Crawford is Robert S. Flinn Professor, Chief, Department of Cardiology, University of New Mexico, Albuquerque.)