Marijuana Use Linked to Rising Cardiovascular Events

Shelley Wood

April 23, 2014

TOULOUSE, FRANCE — Researchers in France are warning that marijuana use may increase the risk of cardiovascular events, particularly in younger adults, with fatal consequences[1].

Their concerns stem from a review of reports made to the French Addictovigilance Network between 2006 and 2010 indicating that almost 2% of reported events concerned cardiovascular complications. What's more, the average age of the people with CV complications was 34, with the number of cardiovascular complications tripling over the study period.

"The general public thinks marijuana is harmless, but information revealing the potential health dangers of marijuana use needs to be disseminated to the public, policymakers, and healthcare providers," lead author Prof Émilie Jouanjus (Centre Hospitalier Universitaire de Toulouse, France) commented in a press statement. This is especially important, given the growing move toward decriminalization of the drug and its use as medical treatment.

Health professionals in France are legally obligated to report "serious cases of abuse and dependence" related to the use of psychoactive substances to the national reporting system, the authors note. Of the 1979 reports over the study period, 35 were cardiovascular in nature. The types of cardiovascular complication ranged from acute coronary syndromes (20 of 35 events), to heart-rate disorders (two events). Ten patients experienced peripheral vascular events, and three patients experienced cerebral-artery events.

Of note, nine subjects died of their CV event (eight of ACS and one of a heart-rate related complication). Most of the reports concerned men (85%), and nine of the subjects had a prior history of cardiovascular disease.

Jouanjus and colleagues, speculating on potential mechanisms, note that cannabinoids have previously been linked to cardiovascular dysfunction. Vasospasm, which has been linked with cannabis use in experimental settings, "could be a possible common origin for many of the cases we describe in the present study."

Commenting on the study for heartwire , Dr Valentin Fuster (Mount Sinai, New York) said the report is timely. "This is an issue that we cannot pass by without paying attention."

Fuster says he first started considering the potential risks of cannabis after seeing a number of young adults at a clinic for young people with coronary artery disease, many of them without traditional risk factors for CVD.

A key question, said Fuster, is the extent to which cigarette smoking also played a role in the current French series—21 subjects were also cigarette smokers—and whether smoking pot is more of a problem than cigarette smoking.

The second question, he continued, concerns "what the actual substance in cannabis is that causes the damage. We know many substances that we inhale can affect the vascular system, so it's not [implausible] that a specific substance could adversely affect the vessel."

Fuster stressed that patient numbers in the series were low and the study is too small to provide definitive answers. "One should be cautious not to overemphasize the problem without more data being available. We need to pay attention, but also not create fear," he said.

The authors had no conflicts of interest. The study was supported by the French InterMinisterial Mission for the Fight Against Drugs and Addiction and by the French drug agency (ANSM).


Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.