Aspirin alone lowers net clinical outcome compared to DAPT after TAVI
Aspirin Alone Versus Dual Antiplatelet Therapy After Transcatheter Aortic Valve Implantation: A Systematic Review and Patient-Level Meta-Analysis
Introduction and methods
Patient undergoing transcatheter aortic valve implantation (TAVI) have a high risk for bleeding and thrombotic events. The current guidelines recommend dual antiplatelet therapy (DAPT) with aspirin and clopidogrel for the first 3-6 months followed by lifelong aspirin [1,2]. Yet, the optimal antithrombotic treatment to minimize the bleeding and thromboembolic risk in patient without a long-term indication for oral anticoagulation after TAVI is not completely determined.
The POPular TAVI cohort A trial in patients without a long-term indication for anticoagulation after TAVI demonstrated a lower incidence of bleeding without increased thromboembolic events with aspirin alone compared to DAPT . This trial was powered for bleeding events and a composite endpoint of bleeding and thromboembolic events. However, it was not powered for thromboembolic events alone.
This study conducted a patient-level meta-analysis in order to increase the statistical power for thromboembolic events by pooling data of 4 RCTs that investigated the efficacy of aspirin vs. DAPT for the prevention of thromboembolic and bleeding events after TAVI in patients without an indication for oral anticoagulation.
4 Prospective RCTs that investigated aspirin alone vs aspirin with clopidogrel were included in the meta-analysis: 1) the POPular TAVI trial (n=665), 2) the ARTE trial (n=222), 3) the SAT-TAVI trial (n=120), and 4) the Dual Antiplatelet Therapy Versus Aspirin Alone in Patients Undergoing Transcatheter Aortic Valve Implantation trial (n=79) [3-6]. All trials randomly assigned patients in a 1:1 ratio to aspirin (80-160 mg daily for the entire trial duration) or DAPT (aspirin 80-160 mg daily with 75 mg clopidogrel daily or ticlopidine 500 mg twice daily for 3 to 6 months followed by 80-160 mg aspirin daily). The primary outcome was the composite of all-cause mortality, major or life-threatening bleeding, and stroke or myocardial infarction. The co-primary outcome was the composite of all-cause mortality, stroke or myocardial infarction. Follow-up was 30 days and 3 months. Outcome data at 30 days were available for all 4 RCTs. The three months follow-up outcomes were available for the POPular TAVI, ARTE, and Dual Antiplatelet Therapy Versus Aspirin Alone in Patients Undergoing Transcatheter Aortic Valve Implantation trials.
- The primary composite outcome of all-cause mortality, major of life-threatening bleeding, stroke and MI at 30 days occurred in 10.3% of patients treated with aspirin alone compared to 14.7% of patients on DAPT (OR 0.67, 95% CI: 0.46-0.97, P=0.0034).
- The co-primary outcome of the composite all-cause mortality, stroke or myocardial infarction at 30 days was similar in aspirin treated patients compared to patients on DAPT.
- The incidence of major bleeding at 30 days was less in the aspirin treated group compared to the DAPT treated group (2.4% vs. 5.9%, respectively, OR 0.40, 95% CI: 0.21-0.78, P=0.007). Also the combination of major or life-threatening bleeding occurred less in patients with aspirin alone than in those treated with DAPT (5.4% vs. 10.1%, respectively, OR 0.51, 95% CI: 0.32-0.82, P=0.005).
- The primary composite outcome of all-cause mortality, major and life-threatening bleeding, stroke or MI after 3 months occurred in 11.0% of patients on aspirin alone compared to 16.5% of patients receiving DAPT (HR 0.66, 95% CI: 0.47-0.94, P=0.02). There was no difference in the co-primary composite outcome of all-cause mortality, stroke or MI between aspirin and DAPT groups.
- There were less major bleedings after 3 months in patients receiving aspirin than in those on DAPT (2.3% vs. 6.4%, respectively, OR 0.35, 95% CI: 0.17-0.71, P=0.004). Also, the incidence of major and life-threatening bleedings combined was lower in the aspirin group compared with the DAPT group (4.8% vs. 10.5%, respectively, OR 0.43, 95% CI: 0.26-0.72, P=0.001).
This meta-analysis showed a lower incidence of the composite of bleedings and thrombotic events after TAVI in patients without a chronic indication for oral anticoagulation treated with aspirin compared to those receiving DAPT at 30 days or 3 months. Furthermore, a reduction in major or life-threatening bleeding and no increase in thromboembolic events were observed in the group treated with aspirin compared to DAPT.