Anticoagulation in type 2 myocardial infarctions: Lessons learned from the rivaroxaban in type 2 myocardial...

Type 2 myocardial infarction (T2MI) occurs when myocardial oxygen demand exceeds myocardial oxygen supply. T2MIs occur more frequently and have worse outcomes compared to Type 1 myocardial infarction caused by an acute plaque rupture. No clinical trial evidence is available to guide pharmacological therapies in this high-risk population.

The Rivaroxaban in Type 2 Myocardial Infarction (R2MI) trial (NCT04838808) was a trainee-led, pragmatic, pilot study that randomised patients with a T2MI to either rivaroxaban 2.5 mg twice daily or placebo. The trial was stopped early due to low recruitment. Investigators explored the challenges of conducting the trial in this population. This was supplemented by a retrospective chart review of 10,000 consecutive troponin assays undertaken during the study period.

Over a 1-year period, 276 patients with T2MI were screened for inclusion of which only 7 (2.5%) were randomised in the trial. Study investigators identified trial design and participant population factors that limited recruitment. These included: heterogeneity of patient presentation, poor clinical prognosis, and lack of dedicated non-trainee study personnel. The major limitation to recruitment was the frequency of identified exclusion criterion. The retrospective chart review identified 1715 patients with an elevated high-sensitivity troponin level, of which 916 (53%) were adjudicated to be related to T2MI. Of these, 94.5% possessed an exclusion criterion for the trial.

Patients with a T2MI are challenging to recruit into clinical trials involving oral anticoagulation. Future studies should account for only ∼1 in every 20 screened individuals being a candidate for study recruitment.