Risk Factors and Prognosis for Clot Formation on Cardiac Device Leads

Authors

  • ATA SOLEIMANI RAHBAR M.D.,

    1. Cardiac Electrophysiology Section, Division of Cardiology, University of California, San Francisco, School of Medicine, San Francisco, California
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  • PEYMAN N. AZADANI M.D.,

    1. Hershey Medical Center, Penn State University, Hershey, Pennsylvania
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  • SINDHURA THATIPELLI B.A.,

    1. Cardiac Electrophysiology Section, Division of Cardiology, University of California, San Francisco, School of Medicine, San Francisco, California
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  • KIRSTEN E. FLEISCHMANN M.D., M.P.H.,

    1. Division of Cardiology, University of California, San Francisco, School of Medicine, San Francisco, California
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  • NHUNHU NGUYEN B.A.,

    1. Cardiac Electrophysiology Section, Division of Cardiology, University of California, San Francisco, School of Medicine, San Francisco, California
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  • BYRON K. LEE M.D., M.A.S.

    Corresponding author
    • Cardiac Electrophysiology Section, Division of Cardiology, University of California, San Francisco, School of Medicine, San Francisco, California
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  • Ata Soleimani Rahbar and Peyman N. Azadani contributed as the first author.

  • Disclosures: The authors do not have any relevant affiliations or financial involvement with any organizations or entities with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript including employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Address for reprints: Byron K. Lee, M.D., The Electrophysiology Laboratories and Clinics, UCSF, Division of Cardiology, 500 Parnassus Avenue, Box 1354, MU 429, San Francisco, CA 94143. Fax: 415-476-6260; e-mail: leeb@medicine.ucsf.edu

Abstract

Background

Clot formation on cardiac device leads is poorly understood. We sought to determine how often clot is seen on device leads by transthoracic echo (TTE), identify risk factors, and to describe the natural history of this phenomenon.

Methods

We reviewed 71,888 echocardiographic studies performed at the University of California, San Francisco from 2005 to 2011. We searched for cases where clot was found adhered to a device lead with no diagnosis of endocarditis. For every case, three age-matched controls with a device but no clot were selected from the echo database.

Results

We found 15 cases with clot adhered to a device lead among 1,086 patients with devices who had TTE (1.4%). In univariate analysis, females had more than four times greater odds of having a clot on their device lead and patients with a history of atrial fibrillation (AF) had an eight times greater odds. Percentage mode switch was also associated with clot formation. Only AF was still associated with clot formation after multivariate analysis. Follow-up data were available for nine of 15 patients. All nine patients had intensification of their anticoagulant/antiplatelet regimen following clot discovery. Complete resolution or shrinkage of clot was observed in eight of nine patients. The one case with no change was a patient who continued taking only aspirin (higher dose) after clot discovery. None of the nine patients had embolic phenomenon.

Conclusion

Patients with AF are at higher risk for clot formation on device leads. After clot detection, treatment with anticoagulants usually results in resolution of the clot without embolic phenomenon.

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