Pacemaker Lead-Associated Innominate Vein Thrombosis Despite Non-vitamin K Oral Anticoagulant (NOAC) Therapy: An Incidental CT Finding.

Venous thrombosis occurring despite therapeutic non-vitamin K oral anticoagulant (NOAC) therapy represents a diagnostic and management challenge, particularly in patients with indwelling cardiac implantable electronic devices. Pacemaker-associated central venous thrombosis is a recognized but often underdiagnosed finding due to its frequently asymptomatic presentation. We report the case of an older adult with a permanent pacemaker implanted approximately 10 months earlier who was undergoing evaluation for unexplained weight loss, in whom cross-sectional imaging incidentally revealed left innominate vein thrombosis without clinical features of venous obstruction. The patient was receiving full-dose NOAC therapy for atrial fibrillation, with good adherence and no alternative provoking factors identified. This case highlights the importance of recognizing venous thrombosis in patients with cardiac implantable electronic devices despite therapeutic anticoagulation and supports a careful, mechanism-based approach to evaluation and management in similar situations.