AMBULATORY BLOOD-PRESSURE MONITORING CAN PLAY AN INTEGRAL ROLE IN PATIENT SELECTION, DOSAGE ADJUSTMENT AND EFFICACY ASSESSMENT IN CLINICAL-TRIALS OF ANTIHYPERTENSIVE AGENTS

Objective: To evaluate the efficacy and duration of action of the angi otensin converting enzyme inhibitor quinapril hydrochloride by using a mbulatory blood pressure monitoring. Design: Eleven centers in the USA and Canada entered 155 patients with previously diagnosed hypertensio n into a 4-week placebo-baseline phase. Twenty patients (13%) with ele vated diastolic blood pressure (DBP) only by cuff measurement were exc luded from entry into a double-blind test based on ambulatory blood pr essure monitoring, and 135 patients with a mean waking blood pressure of 155/100 mmHg were assigned randomly to receive either quinapril or placebo once a day for 8 weeks, with optional titration to a higher do se after 4 weeks, based on the DBP response assessed by repeat ambulat ory blood pressure monitoring only. Results: Quinapril therapy produce d highly significant decrease in mean daytime DBP compared with placeb o. The antihypertensive effect of quinapril was evident over 24 h, wit h 50% of the peak effect remaining at the trough. After 4 weeks of tre atment 49% of the patients in the quinapril group were titrated to the higher dose compared with 86% of the patients who had been receiving placebo. More than 70% of the patients in the quinapril group who rema ined at the low dose would have been titrated to the higher dose based solely on the clinic DBP measurements. Conclusions The use of ambulat ory blood pressure monitoring in the present study reduced the false-p ositive response to placebo and lessened the likelihood of titrating p atients to the higher dose of quinapril in comparison with the number that would have been so treated based on clinic blood pressure measure ments alone. More importantly our results suggest that the convenience , ease and relatively low cost of traditional cuff blood pressure meas urement should be weighed against the potential shortcomings of the me thod.