Pseudohypertension in hypertensive patients on multiple drug therapy.

Differences in blood pressure between direct intra-arterial and indirect cuff measurements have been reported, especially in elderly patients. We investigated the incidence of pseudohypertension among hypertensives with a poor response to drug therapy. We studied 24 patients, aged between 18 and 65 years, whose blood pressure could not be normalized with a combination of at least two antihypertensive drugs. We found no difference in systolic blood pressure but diastolic blood pressure was significantly (P less than 0.001) lower when measured intra-arterially. The mean difference between the direct and the indirect blood pressure determination was 16.2 +/- 1.5 mmHg (s.e.m.), and the range was 2.3-39.6 mmHg. Age, duration of hypertension and left ventricular hypertrophy was not correlated with the incidence and extent of pseudohypertension. We conclude that in hypertensives with a poor response to drug therapy, blood pressure measurements should be taken intra-arterially in order to avoid the hazards of overtreatment.