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1. Twenty-three subjects with essential hypertension were followed for a period of up to 7 years. They were untreated during the investigations. 2. Plasma renin concentration was found to decrease temporarily in some subjects. The ultimate change was a gradual rise. In those subjects who suffered myocardial infarction renin tended to rise more sharply. 3. A relationship was established with the rise in renal vascular resistance, which almost invariably occurred over the years.

Publisher Summary This chapter presents a longitudinal study of the hypertensive process in human. The purpose is to assess trends in plasma renin levels in relation to possible changes in blood pressure, plasma volume, and renal haemodynamics. In an experiment, twenty-three hypertensive patients (11 men, 12 women), aged 22-60 years, were studied for an average period of 4.7 years. The diagnosis of essential hypertension was made after screening the patients for endocrine or renal disorders. At the onset, none of them presented signs of organ damage. Patients had two characteristics in common—they were willing to be recruited for periodical investigations, but they disliked drugs and were definitely undertreated. The results appeared to negate the current practice of labeling hypertensives in terms of low-, normal-, or high-renin hypertension, particularly because some individuals were shown to pass through all stages of the classification of renin levels. As a corollary, it was observed that patients with low-renin hypertension might meet with myocardial infarction after a short lapse of time and only exhibit high-renin levels afterwards. By this finding retrospective studies on renin as a risk factor appear to be invalidated.

SummaryIn 63 patients with uncomplicated essential hypertension plasma renin concentration and renal plasma flow were determined under metabolic ward conditions. Sodium intake was limited to 60 milliequi-valents per day. Patients remained under surveillance for an average period of 54 months.Major cardiovascular complications were observed in 11 subjects (myocardial infarction in 7, stroke in 4). Six of these had low renin hypertension. The claim that low renin hypertension represents a relatively protected condition could therefore not be supported. Nor were these subjects less vasocon-stricted than those with higher renin levels.