Pressure 140 mm hg and diastolic pressure 90 mm hg is

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pressure ≥140 mm Hg and diastolic pressure <90 mm Hg) is recognized as an important risk factor for cardiovascular morbidity and mortality in older adults. Etiology and Pathogenesis Among the aging processes that contribute to an increase in blood pressure are a stiffening of the large arteries, particularly the aorta; decreased baroreceptor sensitivity; increased peripheral vascular resistance; and decreased renal blood flow. Systolic blood pressure rises almost linearly between 30 and 84 years of age, whereas diastolic pressure rises until 50 years of age and then levels off or decreases. This rise in systolic pressure is thought to be related to increased stiffness of the large arteries. With aging, the elastin fibers in the walls of the arteries are gradually replaced by collagen fibers that render the vessels stiffer and less compliant. Differences in the central and peripheral arteries relate to the fact that the larger vessels contain more elastin, whereas the peripheral resistance vessels have more smooth muscle and less elastin. Because of increased wall stiffness, the aorta and large arteries are less able to buffer the increase in systolic pressure that occurs as blood is ejected from the left heart, and they are less able to store the energy needed to maintain the diastolic pressure. As a result, the systolic pressure increases, the diastolic pressure remains unchanged or actually decreases, and the pulse pressure or difference between the systolic pressure and diastolic pressure widens. Diagnosis and Treatment
26 The recommendations for measurement of blood pressure in older adults are similar to those for the rest of the population. Blood pressure variability is particularly prevalent among older adults, so it is especially important to obtain multiple measurements on different occasions to establish a diagnosis of hypertension. The effects of food, position, and other environmental factors also are exaggerated in older adults. Although sitting has been the standard position for blood pressure measurement, it is recommended that blood pressure also be taken in the supine and standing positions in the elderly. In some older adults with hypertension, a silent interval, called the auscultatory gap, may occur between the end of the first and beginning of the third phases of the Korotkoff sounds, providing the potential for underestimating the systolic pressure, sometimes by as much as 50 mm Hg. Because the gap occurs only with auscultation, it is recommended that a preliminary determination of systolic blood pressure be made by palpation and the cuff be inflated 30 mm Hg above this value for auscultatory measurement of blood pressure. In some older adults, the indirect measurement using a blood pressure cuff and the Korotkoff sounds has been shown to give falsely elevated readings compared with the direct intra­arterial method. This is because excessive cuff pressure is needed to compress the rigid vessels of some older persons. Pseudohypertension should be suspected in older adults with hypertension in whom the radial or brachial artery

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