The stent thrombosis events reached a peak at 7 a.m. and a low at 8 p.m. After adjustments, early stent thrombosis still remained significantly associated with the early morning hours.
Blood clots within stents also hit another statistically significant peak in late July/early August. The latter finding suggests that extra activities in the warmer months might contribute to the rise, according to the researchers.
Although potential risk factors documented in some patients, such as heavy physical exertion or medical factors such as surgery, infection and not taking medication correctly, might have triggered some of the blood clots, the data suggested circadian rhythms also played a role, the researchers noted.
A number of factors could explain the rhythms of stent thrombosis, stated the authors. Heart rate, blood pressure and levels of several different hormones have been found to peak in the morning.
"We know that the body basically becomes more hypercoagulable [more likely to clot] in the morning. We know that platelet activity increases in the morning, so all those things together make it more likely for someone to suffer a platelet-mediated event such as a heart attack, stroke or, in this case, stent thrombosis, in the morning," said Dr. Jeffrey Berger, assistant professor of medicine at NYU Langone Medical Center in New York City.
"This may be important in figuring out when somebody should be their taking medicine," he concluded.
The U.S. National Institutes of Health has more about blood clots.
SOURCES: David R. Holmes, Jr., M.D., cardiologist, Mayo Clinic, Rochester, Minn.; Jeffrey Berger, M.D., assistant professor, medicine, NYU Langone Medical Center, New York City; Jacob Shani, M.D., chair, Maimonides Cardiac Institute, New York City; February 2011 '/>"/>
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