Acute ischemic stroke following cardioversion in a patient receiving dabigatran.

OBJECTIVE: To report a case of acute ischemic stroke following electrical cardioversion in a patient currently anticoagulated with dabigatran 150 mg twice daily. CASE SUMMARY: A 74-year-old man, who had been adherent with more than 6 weeks of dabigatran 150 mg twice daily therapy, presented with a dense left-sided hemiparesis 72 hours following a repeat electrical cardioversion. Both computed tomography and magnetic resonance angiogram confirmed a right middle cerebral artery infarct. A transesophageal echocardiogram performed after the cerebrovascular accident failed to demonstrate a cardiac source of embolus. The patient previously underwent cardioversion 4 weeks prior with no evidence at that time of thrombus or spontaneous echo contrast on transesophageal echocardiogram. DISCUSSION: Dabigatran was approved in the United States in late 2010 for the prevention of stroke and systemic embolism in nonvalvular atrial fibrillation. Post hoc data from the phase III trial suggest a low risk of embolism following cardioversion. Since there are no conventional coagulation measures to reliably demonstrate the level of anticoagulation in patients on dabigatran, clinicians must rely solely on patient history when assessing the safety of cardioverting a patient on this medication. Data have suggested increased pro-inflammatory mediators and increased risk of myocardial infarction with oral direct thrombin inhibitors, which may have manifested as a cerebral or carotid artery thrombosis in situ. CONCLUSION: Novel oral anticoagulants are attractive options for anticoagulation required with cardioversion. Although this case report may not preclude use of dabigatran for this purpose, it illustrates that use of this drug is not without risks. Additional investigation into the pro-inflammatory nature of the oral direct thrombin inhibitors is needed.

Warfarin knowledge in patients with atrial fibrillation: implications for safety, efficacy, and education strategies.

BACKGROUND: Multiple factors influence warfarin metabolism and can significantly affect the risk of adverse events. The extent to which patients understand the modifiable factors that impact on warfarin safety and efficacy is unclear. METHODS: A 52-item questionnaire related to knowledge of warfarin was administered to patients with atrial fibrillation in a face-to-face interview with a dietitian. Results were compiled based on five categories: general warfarin knowledge, compliance, drug interactions, herbal or vitamin interactions, and diet. RESULTS: 100 patients were surveyed. Stroke risk factors included hypertension (57%), heart failure (36%), age >75 years (33%), diabetes (22%), and prior stroke/transient ischemic attack (29%). The majority were either high-school (49%) or college graduates (27%). Ten (10%) had a stroke while on warfarin, 11 (11%) had a blood transfusion, and 26 (26%) had at least one fall. The percentages correct for questionnaire items in the five categories were as follows: general knowledge (62%), compliance (71%), drug interactions (17%), herbal or vitamin interactions (7%), and diet (23%). Neither education level nor duration of therapy correlated with warfarin knowledge. Patients at highest risk of stroke had very low knowledge scores in general. DISCUSSION: Patients on warfarin have a poor general understanding of the medication, particularly those at highest risk of stroke.