Any cardiac risk of marijuana would be more serious in people with established heart disease. And that is not a rare scenario, based on data from a federal health survey.
Vaduganathan's team estimates that more than 2 million Americans with heart disease have used marijuana, either now or in the past.
There are many unknowns, including how often people continue to use marijuana after a diagnosis of heart disease and if they believe it is safe.
"I think the next step would be to focus groups, ask patients about current use and their perceptions of the risks," Vaduganathan said.
One concern is that marijuana can interact with the medications that patients with heart disease commonly use, including statins, certain blood pressure medications, and warfarin blood thinner.
"It is anticipated that blood medication levels will change," Vaduganathan said.
His advice for patients is to avoid the use of marijuana during periods of "high risk", such as after a heart attack.
"And we advise against any use of synthetic cannabinoids or vaping in people with established heart disease," Vaduganathan added.
Synthetic cannabinoids, which have names like K2, Spice and Kronic, are man-made chemicals similar to those found in marijuana plants. Vaduganathan said they can be much more potent than marijuana. Similarly, he said, vaping can increase pot potency, and is not a "safer" alternative than smoking.
Dr. Salim Virani is a cardiologist at the VA Michael DeBakey Medical Center in Houston, and president of the Prevention and Leadership Council of the American College of Cardiology.
"We don't have a solid evidence base for marijuana and heart disease like the one we have for smoking cigarettes," Virani said. "Therefore, there is a great need for research in this area. What are the risks? And what is the magnitude of the risks?"
In some cases, he said, doctors may want to evaluate patients for marijuana use, such as people under 55 who have an unexplained heart attack.
Virani also encouraged patients with heart disease to inform their doctors about any use of marijuana.
"As doctors," he said, "we have to be open to having a discussion about it, and be clear about what we know and what we don't know."
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SOURCES: Muthiah Vaduganathan, M.D., M.P.H., cardiologist, Brigham and Women & # 39; s Hospital, Boston; Salim S. Virani, M.D., Ph.D., staff cardiologist, Michael DeBakey VA Medical Center, professor, medicine, Baylor College of Medicine, Houston, and president, Prevention and Leadership Council Section, American College of Cardiology; January 28, 2020,Journal of the American College of Cardiology
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