Cannabis Surgery Risk: 46% Higher Heart Attack Odds

The cannabis surgery risk picture just got sharper: patients who use marijuana face a 46% higher risk of heart attack during or shortly after surgery compared to nonusers, according to a review of five studies covering 44,312 surgical patients presented at the ANESTHESIOLOGY 2026 annual meeting.

A Significant Heart Attack Signal

The researchers found the elevated heart attack risk held across the pooled data, while finding no significant links between cannabis use and stroke, respiratory failure, acute kidney injury, or death. Lead author Nader D. Nader, professor of anesthesiology and surgery at the University at Buffalo’s Jacobs School of Medicine, stressed that the message is about safety, not judgment.

“It is vitally important to tell your anesthesiologist before your procedure if you use marijuana, whether for medical or recreational purposes,” Nader said. “Cannabis can affect your heart, your blood vessels and how your body responds to anesthesia. Knowing about a patient’s cannabis use allows the anesthesiologist to take extra precautions to keep patients safe during and after surgery.”

A Surprising Flip Side

In an unexpected finding, the review also linked cannabis use to a 22% lower risk of venous thromboembolism — dangerous blood clots in the veins. The authors said the result highlights the complex, sometimes contradictory effects of cannabis on the heart and blood vessels, and warrants further study. As marijuana use grows more common and legal in most U.S. states, the findings add urgency to pre-surgery screening conversations.

Source: MedicalXpress