Systolic blood pressure as a risk factor

Epidemiological surveys in the West have demonstrated a consistent rise in systolic pressure with age, whereas diastolic pressure tends to reach a plateau beyond the age of 50 years. This high blood pressure pattern in the elderly population predicts an increasing cardiovascular risk. Traditionally, diastolic rather than systolic blood pressure has been regarded as the main culprit in cardiovascular complications of hypertension. This used to be a valid concept in the case of clinical hypertensive emergencies (accelerated and malignant hypertension). It has become increasingly clear, however, that the risk of incurring the more distant cardiovascular complications in chronic ‘benign’ hypertension appears to be associated with the systolic rather than the diastolic component of arterial pressure. The assessment of increased systolic pressure as a risk factor in its own right can be based on three lines of epidemiological approach. First, the impact of systolic pressure per se may be judged by statistical evaluation of prospectively studied populations with different blood pressures. Second, selected subgroups with ‘isolated’ systolic hypertension may be followed up. The third approach is associated with the results of therapeutic trials. The results appear to confirm that systolic pressure is likely to become the main criterion in the evaluation of hypertension, particularly in the elderly.