Colin E. Widener

Medical University of South Carolina, Charleston, South Carolina, United States

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Publications (2)4.72 Total impact

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    ABSTRACT: Postoperative thromboembolic complications associated with mechanical valve prosthesis implantation can be reduced with either antiplatelet agents or warfarin. Warfarin been shown to be more effective in adults, but the data are less clear in the pediatric population. Seventy-two children and adolescents who survived mechanical valve implantation on the left side of the heart at the authors' institution were followed prospectively from August 1979 until December 2003. All patients underwent surgery before the age of 20 years, and follow up was included up to the age of 20 years. Initially, 53 patients received warfarin alone; mean follow up was 5.9 years, and total follow up 312 patient-years (pt-yr). Likewise, 19 patients received antiplatelet agents; mean follow up was 5.2 years, and total follow up 99 pt-yr. Results were examined using intent-to-treat analyses. Age, gender, race, valve size and position, mean time of follow up and crossover rates were not different between groups. No differences were detected in survival or freedom from thromboembolic and hemorrhagic events. Complications associated with warfarin use were substantially more severe than those associated with antiplatelet agents. The study results were inconclusive due to the small numbers of patient-years of follow up, but suggest that antiplatelet agents may be associated with less severe complications than warfarin. Moreover, warfarin and antiplatelet agents may be equally effective for clotting prophylaxis in children after valve replacement with St. Jude Medical prostheses.
    The Journal of heart valve disease 06/2006; 15(3):394-9; discussion 399. · 0.73 Impact Factor
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    ABSTRACT: Increased systemic levels of the bioactive peptide endothelin 1 during and after cardioplegic arrest and cardiopulmonary bypass have been well documented. However, endothelin 1 is synthesized locally, and therefore myocardial endothelin 1 production during and after cardiopulmonary bypass remains unknown. Pigs (n = 11) were instrumented for cardiopulmonary bypass, and cardioplegic arrest was initiated. Myocardial interstitial and systemic arterial levels of endothelin 1 were measured before cardiopulmonary bypass, throughout bypass and cardioplegic arrest (90 minutes), and up to 90 minutes after separation from bypass. Myocardial interstitial endothelin 1 was determined by microdialysis and radioimmunoassay. Baseline myocardial endothelin 1 levels were higher than systemic endothelin 1 levels (25.6 +/- 6.7 vs 8.3 +/- 1.1 fmol/mL, P <.05). With the onset of bypass, myocardial endothelin 1 increased by 327% +/- 92% from baseline (P <.05), which preceded the increase in systemic endothelin 1 levels. Myocardial compartmentalization of endothelin 1 exists in vivo. Cardiopulmonary bypass and cardioplegic arrest induce temporal differences in endothelin 1 levels within the myocardial interstitium and systemic circulation, which, in turn, may influence left ventricular function in the postbypass period.
    Journal of Thoracic and Cardiovascular Surgery 12/2000; 120(5):864-71. DOI:10.1067/mtc.2000.109700 · 3.99 Impact Factor