Recurrent thrombosis after carotid endarterectomy secondary to activated protein C resistance and essential thrombocytosis: A case report

RATIONALE: Thrombosis is a major cause of morbidity in the perioperative period. Although many risk factors are known, activated protein C resistance is a prominent risk for thrombosis. Activated protein C resistance frequently occurs with recurrent thromboembolism. PATIENT CONCERNS: A 59-year-old Korean woman patient with hypertension was admitted due to dysarthria and left side motor weakness. DIAGNOSIS AND INTERVENTIONS: Magnetic resonance imaging showed subacute cerebral infarction with right frontoparietal lobe and stenosis at the right internal carotid artery. She underwent right carotid endarterectomy under general anesthesia. However, recurrent thrombosis on postoperative day 1 was noted at patient's right carotid artery, which prompted emergency surgery. Additional preoperative laboratory review revealed findings for activated protein C resistance, low protein S activity, antinuclear antibody (>1:160), anti-cardiolipin IgM antibody (16.6), and thrombocytosis, Janus kinase and factor V Leiden mutations. At the intensive care unit, heparin was continually infused until postoperative day 12 and was then switched to warfarin. OUTCOMES: Patient was discharged at postoperative day 21 without any event. Patient had no signs of recurrence within the 3-year follow-up period, and she is still on oral warfarin and clopidogrel. LESSONS: Screening test for hypercoagulability can be used to identify patients at higher risk of postoperative complications. If hypercoagulability state is confirmed by laboratory testing, a suitable anticoagulant treatment plan should be made within the perioperative period.