Research presented in late 2020 (and popularized by an NBC news article) noted mixed results when exploring cannabis use after percutaneous coronary intervention (PCI). PCI involves inserting a tube into arteries clogged with plaque to open them.
From a pool of over 113,000 patients from 48 hospitals in Michigan, cannabis users in general were younger with fewer comorbidities. The University of Michigan researchers matched cannabis users against non-users for comparison and adjusted statistically for those and other differences. Patients self-reported their cannabis use.
The researchers hypothesized that “[cannabis] users are at an increased risk of adverse outcomes after PCI compared with non-users.”
During the 3-year study period, in-hospital outcomes included stroke, bleeding, transfusion, acute kidney injury (AKI), and death. Between cannabis users and non-users, there was no difference between transfusion or death risk.
Risk of bleeding went up for cannabis users (5.2%) compared to non-users (3.4%). Risk of stroke also increased slightly but significantly from 0.1% to 0.3% with cannabis use. Cannabis users fared significantly better than non-users for acute kidney injury (2.2% vs. 2.9%).
The results could be useful when evaluating PCI patients for risk factors. Limitations and close evaluation of the study could not be performed as only the abstract is published. Cardiac issues have been noted as a contraindication for cannabis use. In 2020, The American Heart Association declared that “Cannabis may have therapeutic benefits, but few are cardiovascular in nature.”
Even so, another presentation announced that rather than increase risk of heart arrhythmia after heart attack, cannabis decreased risk for atrial fibrillation (lowering risk for irregular heartbeat). In this case, cannabis was even tied to a lower risk of death.
Cannabis-and-heart research is surprisingly young, making conclusions tough to draw. Currently, it appears to be a mixed bag requiring close evaluation. Patients with risky conditions should always consult with licensed physicians before using cannabis.