No, Kevin Smith's marijuana use was not good for his heart, Temple cardiologist says

Citing the words of one of his physicians, film director Kevin Smith claimed that smoking marijuana may have helped him survive his recent heart attack.

That statement, which the New Jersey native made Tuesday on the Late Show with Stephen Colbert, has cardiologists racing to set the record straight.

If anything, marijuana use may have contributed to his heart disease, said cardiologist Pravin Patil, director of the cardiovascular disease training program at Temple University's Katz School of Medicine.

"I find it really unusual that a doctor would've suggested that to a gentleman presenting with an acute coronary syndrome," Patil said after hearing about Smith's claim.

One big study implicating marijuana as a risk factor for heart disease was conducted at Einstein Medical Center Philadelphia. In their analysis of more than 20 million patient records, Einstein researchers found marijuana use was associated with a higher risk of stroke, heart failure, coronary artery disease, and sudden cardiac death. The researchers also found that marijuana use was linked to other factors known to increase the risk of heart disease, such as obesity, high blood pressure, and cigarette smoking.

So was marijuana directly to blame for causing stroke and heart failure, or was it an indirect connection? Possibly both.

Further analysis showed that regardless of body weight, blood pressure, and the other related risk factors, marijuana use by itself was associated with a 26 percent increase in the risk of having a stroke and a 10 percent increase in the risk of heart failure. The Einstein physicians presented their findings in 2017 at an American College of Cardiology meeting.

And previously, in a smaller study of 3,882 patients, other researchers found the risk of heart attack was up to 4.8 times higher within one hour of using marijuana, compared with people who did not use the drug. On the other hand, long-term studies have not linked marijuana use with a higher risk of dying from cardiovascular disease, according to a 2016 summary on the issue from the American College of Cardiology.

Worth noting: This is a hard topic to study in a randomized trial, the only study design that can establish causation, not just association. Researchers cannot legally hand out joints to study participants. And in the studies that have been conducted, pot smokers represented a small proportion of the overall sample.

Marijuana may contribute to heart disease in multiple ways, said Temple's Patil. It can elevate the resting heart rate and blood pressure as well as the levels of stress hormones, he said. Other studies have shown that smoking marijuana decreases the user's capacity for exercise.

Smith told Colbert he had suffered an especially serious type of heart attack called a "widowmaker," with a 100 percent blockage in the left anterior descending artery.