Supplementary Material for: Efficacy and Safety of Protamine Use Following Transcatheter Aortic Valve Implantation for Minimizing Post-Procedural Bleeding Risk: A Systematic Review and Meta-Analysis

Background: Transcatheter aortic valve implantation (TAVI) may be complicated by postoperative bleeding due to heparin use. Heparin antagonists, such as protamine, have shown potential in reducing bleeding risks. This meta-analysis assesses the efficacy and safety of protamine in reducing bleeding complications after TAVI.
Methods: A systematic search was conducted up to March 2025. Inclusion criteria encompassed studies reporting the use of protamine post-TAVI with a control group. Primary outcomes included major bleeding events as the efficacy endpoint, 30-day mortality, and ischemic events (stroke and transient ischemic attack, or TIA) as safety endpoints. Secondary outcomes included life-threatening bleeding events and the need for blood transfusion. A random-effects model was used to calculate odds ratios (ORs).
Results: Four studies involving 1,569 patients were included. As compared to the control group, protamine was not associated with a statistically significant difference in major bleeding events (OR = 0.59, 95% CI = 0.26 to 1.34, p = 0.21), life-threatening bleeding events (OR = 0.3, 95% CI = 0.06 to 1.62, p = 0.16), need for blood transfusions (OR = 0.75, 95% CI = 0.46 to 1.24, p = 0.27), 30-day mortality (OR = 1.07, 95% CI = 0.54 to 2.11, p = 0.85), or rate of stroke and TIA (OR = 0.86, 95% CI = 0.05 to 13.58, p = 0.91).
Conclusion: Protamine use after TAVI appeared to be safe with no increase in 30-day mortality or stroke and TIA rates, but there was no observed statistically significant benefit in the reduction of major or life-threatening bleeding events and the need for blood transfusions. These findings are based on a limited number of studies, and larger randomized controlled trials are warranted to confirm them.