Evaluating Time in Therapeutic Range in Post-Acute Myocardial Infarction Patients with Left Ventricular Thrombus Treated with Vitamin K Antagonist

Background The standard of care for the treatment of post-acute myocardial infarction (AMI) patients with left ventricular (LV) thrombus is oral anticoagulation with vitamin K antagonist (VKA). Due to the narrow therapeutic range of VKA, patients require frequent monitoring. Adequacy of anticoagulation can be assessed by time in therapeutic range (TTR). This study aimed to evaluate the clinical characteristics and outcomes of post-AMI patients with LV thrombus treated with VKA, stratified by anticoagulation adequacy in terms of TTR ≥70% vs. TTR <70%. Methods Among 3000 consecutive echocardiogram results containing the keyword "thrombus" from December 2013 to August 2017, we identified 87 post-AMI patients complicated by LV thrombus and treated with VKA oral anticoagulation. Demographics, treatment including TTR, and outcome measures were analysed. Results The cohort was followed up for a median of 4.3 years (IQR 3.6 – 5.3). Patients with and without adequate anticoagulation had no significant differences in terms of age (p = 0.859), gender (p = 0.438), co-morbidities, LV ejection fraction (p = 0.638). A majority of post-AMI patients with LV thrombus treated with VKA had inadequate anticoagulation, as only 25.3% (n = 22) had TTR ≥70%. SAMe-TT2R2 score, a clinical predictor score for adequacy of anticoagulation, was high in the study cohort (median 4, IQR 3 – 5), with no significant difference between the two groups (p = 0.907). On multivariable analysis, TTR <70% was significantly associated with higher incidence of combined outcomes (presence of bleeding, stroke, or mortality) (HR 2.91 [95% CI 1.01 – 8.39], p = 0.048). Patients with TTR <70% had a higher cumulative incidence of bleeding events while on anticoagulation (p = 0.036), and a higher cumulative incidence of overall stroke on Kaplan-Meier analysis, but did not achieve statistical significance (p = 0.077). Patients with TTR <70% had a significantly higher cumulative incidence of combined outcomes (both while on anticoagulation and overall) compared to those with TTR ≥70% (p = 0.026, p = 0.017). Conclusion LV thrombus patients treated with inadequate VKA anticoagulation of TTR <70% had overall poorer outcomes compared to TTR ≥70%. Further studies are needed to evaluate anticoagulation adequacy in this population.