Here are the latest studies in hyptension
Gene identified; old drugs pose new questions
The searches for answers about hypertension, its causes, and treatments are at an all-time high. Still, the answers are few, while the studies seem to pose new questions, especially about older drug treatments. Here are summaries of the major research under way:
HT gene is identified.
Two studies funded by the National Heart, Lung & Blood Institute have identified a gene variation dubbed an angiotensin converting enzyme (ACE) gene believed to be a major contributor of hypertension in men, according the May issue of Circulation: Journal of the American Heart Association.
The studies tracked the gene in 1,500 siblings. One study found the ACE variant gene in 30% of the men studied, which in turn led to a 59% increase in the risk of high blood pressure. The second study found that the gene accounted for 38% of the difference in pressure levels among men. The studies also led researchers to determine that the gene is likely sex-specific and is not found in women.
Still, with more study under way, the authors note that tailoring therapy for genetic dispositions, as well as developing genetic tests to determine likely beneficiaries of ACE inhibitor therapy, could be on the horizon.
ACE inhibitors reduce post-MI deaths.
A study of nearly 100,000 heart attack victims who were given ACE inhibitors within 36 hours - and continued to receive them for up to six weeks - has shown that the ACE inhibitors result in five fewer fatalities per 1,000 patients treated, according the June issue of Circulation: Journal of the American Heart Association.
The results led researchers to recommend that ACE inhibitors, if used, can be given "during the first few hours of a heart attack," and have determined that ACE inhibitors can be likened to thrombolytic clot busters. But the study also cited some drawbacks, noting that ACE inhibitor use nearly doubled the risk of low blood pressure episodes and kidney problems.
Beta-blockers limited as preventatives.
Ten studies involving 16,614 patients 60 and older have determined that beta blockers given to treat blood pressure carry no prevention capabilities against heart attack or stroke in seniors who do not have underlying heart disease, according to the June issues of the Journal of the American Medical Association.
The studies back a government panel recommendation from November 1997 against the drug's use as the first option when treating high blood pressure in elderly patients who do not have signs of heart disease.
The JAMA authors believe beta blockers may be overprescribed based on their ability to reduce the incidence of second heart attacks, leading physicians to assume the same for first heart attacks as well.
The study does recommend that beta blockers remain a drug of choice for high blood pressure treatment in elderly patients who do have heart disease, while noting that beta blockers induce more side effects - namely fatigue and depression - than do diuretics.
Teen HT carries risks.
Left ventricular hypertrophy is common among teen-agers with high blood pressure and obesity, according to a study conducted at Children's Hos pital Medical Center in Cincinnati and reported in the May issue of Circulation: Journal of the American Heart Association.
Of 130 adolescents studied, 14% showed thickening of the heart walls, and in 11 of the children, the condition already exceeded the adult at-risk "cutpoint."
"Our study indicates that over half of young people with high blood pressure fall into the intermediateto high-risk group," explains Stephen Daniels, MD, PhD, of Children's Hospital Medical Center. He also notes that the condition "tracks" during a patient's lifetime and that the condition is more prevalent in overweight boys than girls. He recommends annual blood pressure checks beginning at age 4, and calls for weight assessments and echocardiograms for at-risk teens.
Is overnight BP drop a stroke indicator?
Hypertensive patients exhibiting only a minimal drop in overnight blood pressure are at a greater risk of stroke than those whose blood pressure drops, or "dips," during sleep, conclude researchers in Japan. According to the March Stroke: Journal of the American Heart Association, a study conducted at the Second Red Cross Hospital in Kyoto of 105 hypertensive patients showed that those with minimal overnight dips in blood pressure suffered the most severe brain damage during an occurrence of stroke.
Researchers used ambulatory blood pressure monitoring over a 24-hour period, as well as magnetic resonance imaging to determine brain damage from lucaner strokes, also referred to as "silent" brain ischemia due to the lack of obvious symptoms that also can escape exposure via brain imaging.
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