Prolonged anticoagulation after primary PCI for STEMI does not reduce ischemic events

ESC Congress 2023 A Chinese multicenter RCT showed that prolonged, low-dose anticoagulation following primary PCI in STEMI patients was safe but did not reduce the 30-day risk of ischemic events. The choice of anticoagulant possibly played a role in this.

Presented at the ESC Congress 2023 by: Yan Yan , MD - Beijing, China

Introduction and methods

Current guidelines recommend anticoagulation therapy during primary PCI for STEMI. However, it is not clear whether the anticoagulation should be continued after this procedure.

In the RIGHT trial, a prospective, multicenter, double-blind, placebo-controlled, investigator-initiated, superiority RCT conducted in China, 2989 patients with STEMI undergoing primary PCI with bivalirudin were randomized within 4 hours of the procedure to prolonged postprocedural anticoagulation (PPA) or placebo (i.e., no anticoagulation) for ≥48 hours. Prior to initiation of the study, each participating center selected 1 of the following 3 PPA regimens for all their patients: (1) unfractionated heparin 10 units/kg per hour intravenously, adjusted to maintain activated clotting time of 150–220 s; (2) enoxaparin 40 mg once daily subcutaneously; or (3) bivalirudin 0.2 mg/kg per hour intravenously.

The primary efficacy endpoint was a composite outcome of all-cause mortality, nonfatal MI, nonfatal stroke, definite stent thrombosis, or urgent revascularization of any vessel at 30 days. The primary safety endpoint was major bleeding (defined as Bleeding Academic Research Consortium type 3–5) at 30 days.

Main results

• At 30 days, there was no difference in the cumulative incidence of the primary efficacy endpoint between the PPA and placebo groups (HR: 1.00; 95%CI: 0.63–1.57; P=0.988).
• However, secondary exploratory analyses did show a significant interaction between the primary efficacy endpoint and the type of anticoagulant used (P for interaction=0.015), with an HR of 0.46 (95%CI: 0.22–0.98) for enoxaparin versus placebo, 3.71 (95%CI: 1.03–13.28) for unfractionated heparin versus placebo, and 1.24 (95%CI: 0.60–2.59) for bivalirudin versus placebo.
• For the primary safety endpoint of major bleeding, there was no difference in the cumulative incidence between the study arms (HR: 0.74; 95%CI: 0.30–1.83; P=0.511) and no significant interaction by anticoagulant drug (P for interaction=0.679).

Conclusion

Routine prolonged, low-dose anticoagulation following primary PCI in STEMI patients was safe but not superior to placebo in reducing the risk of ischemic events at 30 days. However, the choice of anticoagulant used by each center (unfractionated heparin, enoxaparin, or bivalirudin) could have influenced the 30-day ischemic outcome and warrants further research.

- Our reporting is based on the information provided at the ESC Congress -