Left ventricular thrombus is a common complication subsequent to ST-segment elevation myocardial infarction (STEMI) that related to increased embolic events. This study aims to assess the efficacy and safety outcomes of Rivaroxaban on the prevention of post-STEMI left ventricular thrombus.

According to the newest JAMA review, the incidence of left ventricular thrombus (LVT) in the ST-segment elevation myocardial infarction (STEMI) infarction patients is 15%, with particularly 25% in the anterior STEMI patients. Therefore, it is very necessary to find to strategy to prevent to the left ventricular thrombus formation in STEMI patients.

In the 2013 AHA STEMI guidelines and 2014 AHA stroke prevention guidelines, it was advised to add warfarin to traditional double anti-platelet therapy in anterior STEMI with INR between 2.0 to 2.5. However, date from 2015 to 2017 have suggested potentially less demonstrable benefits with warfarin in the prevention of LV thrombus. In an observational study of 460 patients with anterior STEMI and apical akinesis or dyskinesis who underwent PCI, Le May et al 30 compared outcomes in patients who did and did not receive warfarin. Compared with patients in the no warfarin group, patients treated with warfarin had higher rates of composite all-cause mortality, stroke, re-infarction, and major bleeding within 180 days (15% vs 5%), death (5% vs 2%), stroke (3% vs 0.3%), and major bleeding(9% vs 2%). There were no differences in LV thrombus formation between groups. Another observational study undertaken by Shavadia et al reached a similar conclusion that prophylactic warfarin use was not associated with lower composite end point of recurrent ischemia, stroke/transient ischemic attack/systemic embolism, or all-cause death but was associated with higher major bleeding rates at 1 year (2.5% vs 1.2%). The secondary analysis of the Harmonizing Outcomes With Revascularization and Stents in Acute Myocardial Infarction (HORIZONS-AMI) trial found the same results.

On the other hand, addition of Rivaroxaban to double anti-platelet therapy is very likely to be proved beneficial in STEMI patients. In the Anti-Xa Therapy to Lower Cardiovascular Events in Addition to Standard Therapy in Subjects With Acute Coronary Syndrome 2-Thrombolysis in Myocardial Infarction 51 (ATLAS ACS 2-TIMI 51) trial, the researchers found that the addition of reduced doses of rivaroxaban to double anti-platelet therapy after STEMI reduced a composite of cardiovascular death, MI, or stroke from 10.6% to 8.4% (P = .02) but increased major bleeding (2.2% vs 0.6%; P < .001) and intracranial hemorrhage (0.6% vs 0.1%; P = .02). However, the 2.5-mg twice-daily dose of rivaroxaban when added largely to a background of aspirin and clopidogrel significantly reduced the rate of all-cause mortality vs placebo. What's more, in 2017 the Cardiovascular Outcomes for People Using Anticoagulation Strategies (COMPASS) trial demonstrated that rivaroxaban (2.5mg twice daily) reduced the risk of ischemic events compared with placebo on a back ground of low-dose aspirin in abroad population of patients with stable coronary or peripheral artery disease. Therefore, using low dose rivaroxaban (2.5mg twice daily) to prevent post-STEMI LVT is rather promising.

This study aims to evaluate the therapeutic efficacy and safety of rivaroxaban on the prevention of post-STEMI LVT.

Inclusion Criteria:

• Age:18-80 years old.
• Anterior myocardial infarction diagnosed by 1) typical ischemic symptom, 2) elevated ST segment at the J-point in two contiguous leads (ST elevation should be ≥2mm in men ≥40years; ≥2.5mm in men <40years, or ≥1.5mm in women regardless of age in leads V2 and V3; and ≥1mm in leads other than V2 and V3 ); 3) elevated cardiac troponin value with at least one value above 99th percentile upper reference limit（UPL); 4) confirmed by coronary angiography (CAG) or imaging evidence of new loss of anterior myocardium.
• LVEF < 40% or left ventricular aneurysm detected by either cardiac magnetic resonance (CMR) or TTE during hospitalization.

Exclusion Criteria:

• Any contraindication of anticoagulant therapy or unacceptable risk of bleeding

  1. Active bleeding;
  2. History of intracranial hemorrhage;
  3. Clinically significant gastrointestinal bleeding within 12 months before randomization;
  4. Thrombocytopenia, unknown severe anemia at screening or pre-randomization;
  5. Arterial aneurysm, arterial or venous malformation and aorta dissection.

• Except for subjects who are taking anti-thrombotic therapy (anticoagulation or anti-platelet) at the time of screening

  1. After heart valvular replacement;
  2. History of PCI or CABG;
  3. Subacute bacterial endocarditis;
  4. Venous thrombus, pulmonary thrombi embolism and other thrombophilia under anti-thrombotic therapy.

• Complex heart condition

  1. Cardiac shock (persistent SBP<90 mmHg accompanies with deficient organ perfusion after fluid infusion);
  2. Has ventricular arrhythmias refractory to treatment at the time of randomization
  3. Uncontrolled blood pressure (SBP≥160mmHg);
  4. Undergone or has a CABG planned.

• Severe complication

  1. Body weigh <40kg or >125kg;
  2. Severe chronic or acute renal failure (CrCl <30 mL/min at screening or pre-randomization);
  3. Significantly liver disease，or liver function test abnormal at screening (confirmed with repeat test): ALT >5 times the upper limit of normal or 3 times the upper limits of normal plus total bilirubin >2 times the upper limits of normal;
  4. Severe anemia (i.e. Hemoglobin<9g/dL) at screening or pre-randomization;
  5. Has a current substance abuse (drug or alcohol) problem or a history within the previous 6 months;
  6. Has any severe condition that would limit life expectancy to less than 12 months;
  7. Known allergies, hypersensitivity, or intolerance to rivaroxaban;
  8. Woman who is pregnant, breastfeeding or planning to become pregnant while enrolled in this study;
  9. Has any condition that, in the opinion of the investigator, would make participation not be in the best interest (egg, compromise the well-being) of the subject or that could prevent, limit or confound the protocol-specified assessments.

• Left ventricular thrombus (LVT) detected by either cardiac magnetic resonance (CMR) or TTE during hospitalization.