Marijuana use linked to more complications after coronary bypass surgery | Research

The takeaway

Among 343,796 coronary bypass patients, marijuana users had significantly higher odds of kidney injury (40%), heart attack (56%), and stroke (64%) after surgery, though mortality was not significantly different.

Cardiac surgery patients who use cannabis, cardiac surgeons, anesthesiologists

OR 1.64 for stroke after bypass

What the researchers found

Marijuana users had significantly increased odds of AKI (OR 1.40), AMI (OR 1.56), TIA/stroke (OR 1.64), longer LOS (OR 1.14), and decreased odds of home discharge (OR 1.50). In-hospital mortality showed a nonsignificant decrease (OR 0.41, CI crossed 1.0).

Why it matters

This is the first study examining marijuana use and outcomes after coronary bypass surgery. The elevated complication rates suggest preoperative cannabis screening and counseling may be warranted for cardiac surgery patients.

The numbers in context

343,796 patients (590 marijuana users). AKI OR: 1.40 (1.11-1.78). AMI OR: 1.56 (1.32-1.84). TIA/stroke OR: 1.64 (1.21-2.22). LOS: 10.4 vs. 9.8 days. Home discharge OR: 1.50 (1.24-1.81). Mortality OR: 0.41 (0.14-1.12, NS).

How the study worked

National Inpatient Sample database (2008-2018), 343,796 CABG patients (590 marijuana users). Multivariable models adjusted for confounders compared outcomes between marijuana users (abuse/dependency codes) and non-users.

What this study cannot tell us

Administrative database using ICD codes for marijuana abuse/dependency likely captures only severe use. Younger marijuana users may differ in other risk factors. Cannot assess cannabis consumption method, frequency, or timing relative to surgery.

How to read the evidence

Large national database with multivariable adjustment, but ICD-based exposure measurement captures only severe use and small marijuana group limits precision.

When this study was published

2024 analysis of National Inpatient Sample data from 2008-2018

The bigger picture

Marijuana users were significantly younger (mean 56 vs. 66 years), suggesting they developed coronary disease requiring bypass at earlier ages. The combination of earlier disease and worse surgical outcomes raises concerns about cardiovascular health in chronic cannabis users.

Questions still open

Should marijuana users be counseled to abstain before cardiac surgery? Is the younger age of bypass surgery in marijuana users a coincidence or evidence of accelerated coronary disease?

Common questions

Does marijuana increase the risk of complications after heart surgery?

In this study, marijuana users had significantly higher odds of kidney injury, heart attack, and stroke after coronary bypass surgery, though mortality was not significantly different.

Why were marijuana users younger?

Marijuana users averaged 56 years compared to 66 for non-users. This could suggest cannabis contributes to earlier coronary disease, though the study could not determine causation.

Read the original research

Association Between Marijuana Use and Clinical Outcomes After Coronary Artery Bypass Grafting.

The Journal of surgical research, 295, 442-448

View on PubMed ↗Publisher’s paper ↗

Citation

Bellam, Krishna G; Sabe, Sharif A; Chalasani, Nishanth; Feldman, Noah; Huang, Nicholas R; Harwell, Anthony; Sellke, Frank; Ehsan, Afshin. (2024). Association Between Marijuana Use and Clinical Outcomes After Coronary Artery Bypass Grafting.. The Journal of surgical research, 295, 442-448. https://doi.org/10.1016/j.jss.2023.11.015