HYPERTENSION AND DEMENTIA
The build-up of plaque in the arteries of the body is known as atherosclerotic cardiovascular disease (CVD). CVD is very common in the general population, affecting the majority of adults, to varying degrees, past the age of 60 years. Common deadly and disabling complications of CVD include: coronary artery disease/heart attack, cerebrovascular disease/stroke/dementia, congestive heart failure, and renal failure. These conditions can result in significant disability and mortality. People at increased risk for CVD have the following major risk factors: hypertension, diabetes mellitus, cigarette smoking, obesity, sedentary life style/deconditioning, hyperlipidemia/elevated cholesterol, and a family history of premature CVD.
Hypertension ranks as the number one modifiable risk factor for developing CVD and this has been documented by many quality clinical trials. Despite this knowledge, estimates are that over 50 % of adults treated for hypertension do not have adequate blood pressure control. The average American requires three anti-hypertensive medications to meet goal blood pressures.
The following are the current definitions and staging adopted by expert scientist:
· Normal blood pressure – systolic (top number) less than 120 mmHg and diastolic (bottom number) less than 80 mmHg.
· Elevated blood pressure – systolic 120 – 129 mmHg and diastolic greater than 80 mmHg.
Stage 1 - systolic 130 -139 mmHg or diastolic 80 - 89 mmHg.
Stage 2 – systolic at least 140 mmHg or diastolic at least 90 mmHg.
If there is disparity in category between the systolic and diastolic pressures, the higher value determines the stage.
A blood pressure measurement obtained in a clinical setting (physician’s office or other healthcare facility) should be used as a screen for hypertension. If the blood pressure is found to be elevated, a definitive diagnosis of hypertension requires integration of a diary of home blood pressure checks or blood pressures obtained by wearing an automated ambulatory blood pressure monitor.
The impact on CVD risk with lowering blood pressure is significant with some clinical studies demonstrating a risk reduction of 10 – 20% for stroke or heart attack when systolic blood pressure improves from 140 mmHg to 120 mmHg. Other studies have demonstrated a doubling of heart attack and stroke risk for every 20 mmHg increase in blood pressure beginning with a systolic blood pressure of 115 mmHg and extending out to 180 mmHg. As an example, a population of people with an average systolic BP of 135 mmHg have twice the risk for stroke or heart attack when compared with a population of people who average 115 mmHg!
Hypertension is considered a risk for dementia, particularly vascular dementia, but also Alzheimer’s disease. Nonetheless, short term trials of blood pressure lowering therapy have shown inconsistent effects on cognitive (mental) impairment. A biomarker of cerebral (brain) vascular disease is the finding of tiny lesions in the white matter of the brain due to arteriosclerosis, or “hardening of the arteries”. These lesions are noted on brain MRIs in normal asymptomatic older patients; however, they seem to be more prevalent at an earlier age in untreated hypertensive patients and have been termed by some as mini-strokes.
In a clinical trial published this year, a large cohort of patients older than 75 years were randomly assigned to either a more intensively treated BP group (systolic BP averaging 120 mmHg) or less intensively treated group (systolic BP averaging 140 mmHg). At 5 years, the rates of dementia and cognitive impairment were lower in the more intensively treated group. A subset of trial participants underwent brain MRIs with the finding that the arteriosclerotic brain lesions (described above) increased but to a significantly lesser degree than the intensively treated group. These results suggest that intensive blood pressure lowering inhibits the progression of the arteriosclerotic brain lesions and may reduce the risk of dementia in older patients.
Another trial published this year, showed cardiovascular benefits with intensive blood pressure lowering in older hypertensive adults. This trial, involving patients 75 years or older, confirmed a reduction in cardiovascular complications and all-cause mortality after only 3 years of intensive blood pressure lowering (24-hour average systolic equal to 130 mmHg compared with average pressures of 145 mmHg). Also, as noted in the above study, there was definitive slowing of the progression of arteriosclerotic brain lesions.
These two very recently published studies confirm many previous trials that have demonstrated the many health benefits (including prevention of dementia) of treating blood pressure elevations, at any age.
As a result of the findings in the two recent studies described, the paradigm is intensive blood pressure lowering, which in most cases will require multiple anti-hypertensive medications, in addition to adherence to appropriate lifestyle modification.
Dr. Tippett is the founder of Comprehensive Quality Healthcare Provide, a concierge internal medicine and geriatrics practice, located at 1210 Commerce Dr., Suite 106, Greensboro, Ga. 30642. He can be reached at 706-510-3659. Visit his web page at www.drtippett.com.