Pathophysiology of hypertension in the elderly

The importance of hypertension as a cardiovascular risk factor increases progressively with aging, but diastolic blood pressure plateaus at age 50, which leads to a rise in pulse pressure in the elderly. Thus, isolated systolic hypertension with a widened pulse pressure is the most common type of hypertension seen in persons older than 65 years of age. Pulse pressure is the most robust blood pressure measurement in predicting cardiovascular disease. This rise in systolic blood pressure and pulse pressure with aging is a consequence of arterial stiffness. With aging, both structural and functional changes occur that result in a less compliant aorta and large vessels. Investigators who use pulse-wave velocity and augmentation index as measures of large artery stiffness have repeatedly shown an increase in arterial stiffness with aging. Early return of the reflected pulse wave to the aorta during systole has been shown to be the primary mechanism accounting for the rise in systolic and decline in diastolic pressure that occurs with arterial stiffness. Several factors have been shown to decrease arterial stiffness including aerobic exercise, decreased sodium intake, n-3 fatty acids, estrogen replacement therapy, nitrates, and ACE inhibitors. Drugs that specifically lower systolic blood pressure but not diastolic pressure, such as vasopeptidase inhibitors, are under investigation in treating isolated systolic hypertension.