SAN FRANCISCO – Lowering blood pressure below 140/90 mm Hg might not be a good idea in the very elderly, especially if they have cognitive impairment, according to Philip Gorelick, MD.
“Lower blood pressure” in those patients “may be associated with worse cognitive outcomes,” he said at the joint scientific sessions of AHA Council on Hypertension, AHA Council on Kidney in Cardiovascular Disease, and American Society of Hypertension.
The problem is that higher pressures may be needed to maintain cerebral perfusion. It’s possible the very elderly have impaired cerebral autoregulation, especially if there’s a history of hypertension. A little extra pressure is needed to overcome increased cerebral vascular resistance.
“Cautious blood pressure–lowering with a target of about 150 mm Hg systolic, may be prudent,” said , professor of translational science and molecular medicine at Michigan State University in Grand Rapids. Meanwhile, “for those without cognitive impairment and who have intact cerebral autoregulation, lower blood pressure targets may be beneficial to preserve cognition.
It’s become clear in recent years that cognitive decline is not a strictly neurologic issue, but rather related to cardiovascular health, at least in some people. Good blood pressure control in midlife, in particular, seems to be important for prevention.
“The same risk factors for atherosclerotic disease [are] risks for Alzheimer’s disease. Vascular risks play a role in cognitive impairment, including Alzheimer’s,” he said.
But the evidence is not clear for blood pressure lowering after the age of 80. Several studies have suggested that angiotensin receptor blockers and other hypertension medications reduce pathologic and clinical changes associated with Alzheimer’s. “However, there’s certainly a downside” to using them in the elderly. “Everything that glistens is not gold,” Dr. Gorelick said.
“There have been studies in older persons with mild cognitive deficits who are placed on antihypertensives, and they actually have lower brain volumes: The brain is shrinking, possibly at a faster rate. Other studies have suggested that people around 80 years of age may have greater cognitive decline with lower blood pressure,” he said.
For those older than 80 and patients with cognitive impairment, the usefulness of blood pressure–lowering for prevention of dementia has not been established. Relaxing the blood pressure control targets might prevent harm, he said.
“There’s going to be a window of opportunity where were are going to see some benefit” in using, for instance, ARBs to slow cognitive decline, but “we have to be smart enough to find the right patients and the right window. We’re not there yet,” he said.
Dr. Gorelick is a consultant for Bayer, Novartis, and Amgen.