[Ambulatory or single measurement of blood pressure: comparison in a controlled trial in patients with hypertension].

Single measurement during a visit and the calculation of blood pressure pattern from an ambulatory record are different criteria for evaluation of the efficacy of antihypertensive treatment. Results obtained by these two methods were compared in a controlled trial. Acebutolol or enalapril were given double-blind to 17 patients with uncomplicated moderate essential hypertension. After a two week run-in period (with dummy treatment), patients were allocated at random into two parallel groups. They took acebutolol (400 mg) or enalapril (20 mg) as a single daily dose for 3 months. Ambulatory measurement of blood pressure for 24 hours (Spacelabs 5200 SPM) was carried out the day prior to final inclusion, and at the end of the first then the third month of active treatment. A single measurement of blood pressure took place at the same times. Safety/acceptability of treatment based upon clinical and laboratory parameters was good. At inclusion, single measurements showed that all patients had a diastolic blood pressure (DBP) over 95 mmHg. However, ambulatory BP was significantly lower in the enalapril group. With treatment, the fall in DBP by single measurement was significant only at the first month with enalapril and at the third month with acebutolol while the effects of both drugs were significant on ambulatory systolic blood pressure (SBP) and DBP by the first month. Ambulatory BP revealed a superior antihypertensive action of acebutolol on SBP at the third month but this was not shown by single BP measurements. These results confirm the specificity of trial protocols of antihypertensive drugs based upon ambulatory BP measurements.