Controlling Blood Pressure
How low is low enough?
How low to lower blood pressure? The changing tides of hypertension control are making treating physicians and patients alike dizzy. Nothing stays static forever in medicine, but the rapid fire change in ideal blood pressure goals over the last few years is nothing less than “dizzyfying” – common New Orleans lingo for lightheadness.
“Blood pressure is a vital sign, not a disease. The disease is hypertension,” says Dr. Thomas Giles, a cardiologist at Tulane and former president of the American Society of Hypertension. Transient elevations of blood pressure are normal and expected. Sustained elevations over time define the disease hypertension. Higher than normal blood pressure causes vascular damage, a potent cause of heart, brain, eye and kidney complications.
A blood pressure reading has two numbers. The systolic pressure, the first and higher number, is measured when the left ventricle contracts, causing the surge of oxygenated blood that make body functions work. The lower number or diastolic pressure reflects the resting blood pressure between the heart’s forceful contractions. An optimal blood pressure for a person not diagnosed and under treatment is 120/80 or less. Any sustained systolic pressure above 140 or diastolic pressure above 90 defines hypertension according to the American Heart Association.
An elevated diastolic blood pressure over 90 is the most potent risk factor for vascular complications related to hypertension before age 50. After age 50, rises in systolic blood pressures become worrisome. Beginning in 2004, attention to elevated systolic blood pressure took center stage for the first time. Physicians, who previously had let elevated systolic blood pressures in older adults slide, began prescribing more medications in an effort to keep systolic blood pressures below 140.
Systolic hypertension is more difficult to treat than diastolic elevations. It usually takes two or more drugs to drop systolic blood pressure elevations below 140. The number of drugs prescribed for hypertension more than tripled in the decade following 2003.
Back in 1977, a “joint national committee” first convened to define hypertensive terms and to suggest treatment goals. This first committee ignored systolic pressure, picking a diastolic blood pressure of 105 to define hypertension needing treatment. The National Heart, Lung and Blood Institute has periodically appointed new committees to issue updated definitions and treatment guidelines.
The eighth rendition of these national committees suggested treatment goals that upset hypertensive specialists in late 2013.
“If you get patients’ blood pressure below 150, I believe you’re doing as well as can be done based on scientific evidence,” said a committee co-chair who’s a family practice physician at the University of Iowa. “The mantra of blood pressure experts in the past has been that lower is better. Recent studies don’t seem to support that,” added the other co-chair, a hypertensive expert at the University of Alabama in Birmingham.
These 2013 major shifts in less intensive treatment for hypertension made sense to many seasoned primary care physicians, who were concerned by the exponential increase in medication use and adverse effects in the elderly and frail. For example, one problem that increases with age and polypharmacy is orthostatic hypotension, an abnormal drop in blood pressure when one stands that can cause dizziness, falls and broken hips.
On the other hand, cardiologists and hypertensive experts across the United States cried foul. By the time the 2013 guidelines were released, the National Heart, Lung and Blood folks had jumped ship, saying they wanted out of the guideline business. The present-elect of the American Heart Association bashed the guidelines. The American College of Cardiology offered no support. Even some of the original committee members published a paper in another journal recanting support for the new recommendations.
If these loosening blood pressure control recommendations were a tidal wave, what hit the hypertensive community in September 2015 was a major tsunami. The National Institutes of Health began the Systolic Blood Pressure Intervention Trial or SPRINT in 2009. Some 90 medical centers and clinics across the United States participated in this study budgeted at $114 million dollars and set to run for nine years. Four sites in Louisiana were selected, including Tulane and Ochsner locally.
Persons over age 50 with systolic blood pressures of 130 or higher enrolled. Each had at least one cardiac risk factor, such as a prior heart attack, chronic kidney disease or were older than age 75. The study excluded those at the highest risk for heart attacks and strokes, such as persons with prior strokes, diabetes, recent heart failure and dementia.
Using standard antihypertensive medications, the 9,000-plus study participants were randomized to receive either tight or loose blood pressure control. The tights had intense attention and medication add ons to keep their systolic blood pressure at 120 or less. The loose group received whatever medications they needed to lower their systolic blood pressure to at least 140.
The intent was to follow these older Americans for five years and to see if there were any outcome differences between loose and tight blood pressure control. This study was prematurely aborted earlier this year after an interim analysis showed a clear difference in outcomes between the groups. Deaths were 25 percent lower in the tight control group, those targeted for a systolic blood pressure of 120 or less.
So what to do? Many seasoned and thoughtful physicians are fed up with the endless proliferation of guidelines. The supporting evidence cited by various professional societies, drug companies and advocacy groups is often low quality. Obvious and hidden agendas are common. For example, urology groups stress more PSA testing, radiologists recommend more frequent mammograms, and physicians aligned with pharmaceutical companies drive medication recommendations.
“Normalizing blood pressure is a good idea, but you must use common sense and be careful. One size does not fit all,” says Dr. Giles, noting that dropping blood pressure too low in many patients can be dangerous including those with advanced age, heart valve abnormalities and advanced renal failure.
Bottom line: Beware of cookbook medicine driven by blind adherence to guidelines and protocols.
“This news was exciting and clear: Targeting a systolic BP of less than 120 can reduce the huge morbidity and mortality burden associated with hypertension. Age is a powerful risk factor for hypertension complications, especially in blacks, women and other high-risk groups. Contrary to controversial declarations made in medical papers over the last two years, a lowered blood pressure control may help older individuals live longer and avoid catastrophic heart attacks, strokes, heart failure and premature cardiovascular deaths.”
– Dr. Ferdinand is a cardiologist at Tulane University School of Medicine. His comments were adapted from his editorial comments in Cardiology Today, a news magazine targeted to the cardiovascular professionals.