Apical hypertrophic cardiomyopathy complicated by multisystem embolism, anticoagulant overdose-induced iliopsoas hematoma, and subsequent cardiocerebral infarction: a cautionary case report on DOAC dosing in renal impairment

Background Apical hypertrophic cardiomyopathy (ApHCM) is a morphological variant of hypertrophic cardiomyopathy characterized by relative apical hypertrophy (wall thickness ≥ 15 mm) with a relatively favourable prognosis. Approximately 30% of patients with ApHCM develop one or more adverse cardiovascular complications, among which atrial fibrillation (AF) is the most prevalent, with a reported incidence of 12%. Atrial fibrillation (AF) is a common cardiac arrhythmia and a major risk factor for stroke and systemic thromboembolism. Case presentation A 78-year-old man complained of a 1-day history of severe, lower abdominal pain associated with nausea and hematuria. Simultaneous renal infarctions and splenic infarctions were then diagnosed. The patient was initiated on subcutaneous enoxaparin sodium injection 4000 anti-Xa IU /12 h, and his abdominal pain improved after six days of anticoagulation. Anticoagulation therapy was transitioned to oral edoxaban 60 mg once daily after discharge. Five days later, the man was admitted to our emergency room again with complaints of progressively increasing right lower quadrant abdominal pain and a large palpable abdominal mass. Pelvic magnetic resonance imaging revealed an oval, irregular heterogeneous signal lesion measuring 7.9 × 5.8 cm adjacent to the right iliopsoas muscle, consistent with a hematoma. Conclusions In patients with acute renal infarctions and secondary upward-trending creatinine, the treatment decisions regarding anticoagulants are of crucial importance as the worsening kidney function can considerably increase the incidence of embolism and bleeding. For this patient with progressively elevated serum creatinine and a creatinine clearance of 39.7 mL/min, the administration of edoxaban 60 mg once daily was an iatrogenic dosing error. This guideline-noncompliant full dose resulted in a rare iliopsoas hematoma. According to clinical guidelines, edoxaban is indicated for stroke prophylaxis in patients with atrial fibrillation. For those with creatinine clearance (CrCl) ranging from 15 to 50 mL/min, the standard reduced dose is 30 mg once daily.