Low Blood Pressure Risky for Heart Patients?
Controversial Study Shows Very Low Blood Pressure May Raise Risk of Heart Attack, Stroke
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Blood Pressure: The Lower the Better? continued...
In the study, a pressure of 140.6/79.8 was linked with the lowest rate of heart attack and stroke.
In general, Messerli says, doctors have long believed "the lower the better" when it comes to blood pressure. His study suggests that may not be so for those with known coronary artery disease. "The dictum 'the lower the better' does not apply for the TNT coronary heart disease population," he tells WebMD.
He concludes that a so-called J-curve relationship exists -- that is, pressures either too high or too low adversely affect the risk of heart attack and stroke. Why low pressure would do that is not certain, he says.
Blood Pressure: Study Details 'Sketchy'
Much more study is needed on the proposed relationship between very low blood pressure and the risk of cardiovascular events, says Black.
"The details are too sketchy to make any recommendation at all," he says. The J curve, he adds, has been discussed for decades among high blood pressure experts. He says most cardiology experts don't believe it exists.
The original intent of the TNT study, he says, was not to look at blood pressure but to look at aggressive lowering of LDL cholesterol and its effects on heart attacks and strokes in patients with coronary artery disease.
"This data needs to be dissected," agrees Ravi Dave, MD, a cardiologist at Santa Monica-UCLA and Orthopaedic Hospital and clinical associate professor of medicine at the University of California Los Angeles David Geffen School of Medicine, who also reviewed the analysis for WebMD.
In clinical practice, Dave says, he tends to keep patients with coronary artery disease at systolic pressures higher than 100. "Once patients' systolic pressure gets lower than 100, they will have side effects of fatigue, dizziness, tiredness, and they may even lose consciousness," he says.
The findings apply only to those with known coronary artery disease, Messerli cautions, and not to the general population.
His advice? If someone has known coronary artery disease, ''you want to be a bit careful in lowering the blood pressure."
Black cautions that patients on blood pressure lowering drugs should never stop or adjust their doses without consulting the doctor who prescribed them.