Cannabis users had worse bypass outcomes, increased amputation and opioid use

Just over 125 of 100,000 people in the U.S. will have a bypass procedure.

5:00 AM

Author | Noah Fromson

cannabis leaf lab note logo yellow blue
Justine Ross, Jacob Dwyer, Michigan Medicine

The use of cannabis may have a negative impact on outcomes for a common bypass surgery, a study suggests.

Researchers at Michigan Medicine analyzed more than 11,000 cases from the Blue Cross Blue Shield of Michigan Cardiovascular Consortium, known as BMC2, to review patient cannabis use and postoperative outcomes for lower extremity bypass after 30 days and one year. The minimally invasive procedure, also called a peripheral artery bypass, involves detouring blood around a narrowed or blocked artery in one of the legs with a vein or synthetic tube.

Results published in Annals of Vascular Surgery reveal that patients who used cannabis prior to lower extremity bypass had decreased patency, meaning the graft had a higher chance of becoming blocked or occluded, and were 1.25 times more likely to require amputation one year after surgery. Cannabis users were also 1.56 times more likely to use opioids after discharge.

"The findings show a need for screening for cannabis use and open conversations between patients and clinicians to help inform preoperative risk assessment and decision-making for lower extremity bypass," said senior author Peter Henke, M.D., FACS, FAHA, director of the University of Michigan Health Frankel Cardiovascular Center and director of BMC2 Vascular Surgery.

"While its exact mechanisms are unclear, cannabis and its active compounds play a role in platelet function and microcirculation that may lead to decreased rates of limb salvage after lower extremity bypass," Henke said.

Around 43% of individuals in the United States and Canada have used cannabis. Previous studies suggest cannabis use has effects on the cardiovascular system, including increased risk of heart attack and stroke. However, it was not associated with stroke or heart attack after lower extremity bypass for patients in the study.

While future study is needed to further understand cannabis' full effect on outcomes, researchers note, the findings will help clinicians counsel patients who are undergoing vascular surgery.

"While past studies on the effects of cannabis use on pain response suggested an increase in pain tolerance after smoking cannabis, our studies and other contemporary findings show the opposite," said Drew Braet, M.D., first author and integrated vascular surgery resident at U-M Health. "Given the increase in cannabis use and abuse in conjunction with the opioid epidemic, the results suggest a need for a better understanding of pain management for cannabis users who are having vascular surgery."

Additional authors include Jeremy Albright Ph.D., Craig Brown M.D., Nicholas H. Osborne M.D., all of Michigan Medicine.

Support for BMC2 is provided by Blue Cross and Blue Shield of Michigan and Blue Care Network as part of the BCBSM Value Partnerships program. Although Blue Cross Blue Shield of Michigan and BMC2 work collaboratively, the opinions, beliefs and viewpoints expressed by the author do not necessarily reflect the opinions, beliefs, and viewpoints of BCBSM or any of its employees.

Paper cited: "Impact of Cannabis Use on Outcomes after Lower Extremity Bypass," Annals of Vascular SurgeryDOI: 0.1016/j.avsg.2022.09.037


More Articles About: Lab Notes All Research Topics Peripheral Artery Disease (PAD) Vascular Disease Vascular Surgery Community Health Future Think Hospitals & Centers Surgery Pre- and Post-Operative Surgery Types Cardiovascular: Diseases & Conditions
Health Lab word mark overlaying blue cells
Health Lab

Explore a variety of health care news & stories by visiting the Health Lab home page for more articles.

Media Contact Public Relations

Department of Communication at Michigan Medicine

[email protected]

734-764-2220

Stay Informed

Want top health & research news weekly? Sign up for Health Lab’s newsletters today!

Subscribe
Featured News & Stories balancing scale of food and hand reaching purple background yellow scale
Health Lab
All FODMAPs aren’t created equal: working toward alternative diets to manage IBS
Two studies from Michigan Medicine may provide hope for patients with irritable bowel syndrome (IBS) struggling to implement the traditional low-FODMAP diet.
woman sitting at table in stripe shirt stressed seeming white background window
Health Lab
An unequal toll of financial stress
Inflation rates may have cooled off recently, but a poll shows many older adults are experiencing financial stress – especially those who say they’re in fair or poor physical health or mental health
woman laying down and sheet over going into surgery
Health Lab
Older women more likely to receive heart surgery, die at low quality hospitals
Women over the age of 65 who require complex heart surgery are more likely than men to receive care at low quality hospitals — where they also die in greater numbers following the procedure, a Michigan Medicine study finds.
sunscreen blue people outside
Health Lab
Sunscreen dispensers make skin cancer prevention easier
Medical students have worked to place dispensers at parks, pools and golf courses around Washtenaw County to give people easy access to sunscreen.
Cancer cell microscopic, colored yellow
Health Lab
Researchers find common immune system mechanism between pregnancy, cancer
Researchers find common immune system mechanism between pregnancy, cancer
food photo
Health Lab
Nanoparticles reprogram mouse immune systems to cope with allergens
Two doses of allergen-encapsulating nanoparticles delivered intravenously prevented anaphylaxis during a food allergy test in mice, according to new research.