Phenotypes of Hypertension: Impact of Age and Sex on Hemodynamic Mechanisms

BACKGROUND: Essential hypertension is often treated as a uniform condition. However, it encompasses distinct patterns of blood pressure elevation such as isolated systolic, systolic diastolic, and isolated diastolic hypertension, which vary in prevalence according to age and sex. We hypothesized that different hemodynamic mechanisms account for the age- and sex-related differences in these hypertensive phenotypes. METHODS: In this cross-sectional analysis of the ACCT (Anglo-Cardiff Collaborative Trial), 5371 individuals (2402 male), aged 18 to 92 years, free of cardiovascular disease and medication were included. Blood pressure, cardiac output, stroke volume, peripheral vascular resistance (PVR), and aortic pulse wave velocity were measured. Within each sex, subjects were stratified according to age (<30, 30-60, and >60 years), and blood pressure phenotype based on clinic (seated) blood pressure. RESULTS: Isolated systolic hypertension was the most common hypertensive phenotype in young men and characterized by an elevated cardiac output and stroke volume. In contrast, systolic diastolic hypertension and isolated diastolic hypertension were more common in younger females, with systolic diastolic hypertension associated with elevated PVR and aortic pulse wave velocity, and isolated diastolic hypertension with increased PVR. Systolic diastolic hypertension was the most common phenotype in middle age and accompanied by increased PVR in both sexes. Isolated systolic hypertension was again the most common phenotype in older individuals. However, in contrast to younger adults, isolated systolic hypertension affected both men and women equally (~1:1) and was characterized by elevated aortic pulse wave velocity and PVR. CONCLUSIONS: Different hypertensive phenotypes are characterized by distinct hemodynamic mechanisms in an age- and sex-dependent manner. Targeting therapy toward primary hemodynamic abnormalities could lead to more effective interventions in essential hypertension.