Pathogenesis of human primary hypertension: a new approach to the identification of causal factors and to therapy.

In chronic renovascular hypertension the amplifier properties of the hypertrophied heart and vessels contribute considerably more to the maintenance of the elevated blood pressure (BP) than the basic underlying cause. This must also occur in chronic primary hypertension. Accordingly, we hypothesized that after reversal of hypertrophy by antihypertensive medication the cause(s) of hypertension should be easier to detect during the redevelopment of hypertension once medication was stopped, than in the chronic phase of the disorder. We have studied three groups of patients with moderate to severe hypertension in whom BP was controlled for (1) 1 month (2) 1 year and (3) 15 months to 5 years. The rate of subsequent redevelopment of hypertension between the series was inversely related to the duration of therapy, which was mostly with beta-blockers and diuretics. Redevelopment of hypertension was slowest after obtaining regression of both vascular hypertrophy and left ventricular hypertrophy (LVH). Preliminary findings suggest that sympathetic overactivity is present during the redevelopment phase in most patients. Our findings have suggested a new therapeutic strategy, where the effectiveness of non-pharmacological methods of controlling BP is enhanced by first causing regression of cardiovascular hypertrophy by drug treatment. Moderate regular exercise has proved to be an effective non-pharmacological antihypertensive method which has now maintained five patients at normal BP for 1 year, following an initial period of drug treatment.