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Abstract: FR-PO174

Effect of Warfarin on Progression of Vascular Calcification

Session Information

Category: Bone and Mineral Metabolism

  • 402 Bone and Mineral Metabolism: Clinical

Authors

  • Alappan, Harish Raj, Emory University - Undergraduate, Atlanta, Georgia, United States
  • Kaur, Gurleen, Emory, Decatur, Georgia, United States
  • O'Neill, W. Charles, Emory University, Atlanta, Georgia, United States
Background

Advanced chronic kidney disease (CKD) and end-stage renal disease (ESRD), as well as diabetes are potent risk factors for medial arterial calcification, a lesion associated with poor cardiovascular outcomes. Warfarin use may be an additional risk factor, possibly by reducing levels of matrix gla protein, a vitamin K-dependent inhibitor of vascular calcification. To quantify the effect of warfarin on medial arterial calcification and determine if this is augmented in CKD and ESRD or diabetes, we retrospectively measured the progression rate of breast arterial calcification (BAC), a marker of systemic medial arterial calcification in women with or without warfarin use.

Methods

Subjects with and without warfarin use were identified from an electronic medical record search of all digital mammograms at Emory Healthcare. Records were manually reviewed to identify mammograms performed during warfarin use. Subjects without baseline calcification were excluded. Control patients were selected to match the eGFR range in warfarin patients. Lengths of calcified arteries were measured on digital mammograms separated by > 1 year. Progression rates are reported as mm/breast/y and expressed as medians and interquartile ranges. Statistical significance was determined by the Mann-Whitney U and Wilcoxon tests.

Results

Of the 77 sets of mammograms, eGFR was >60 in 36 and <60 in 28, and ESRD was present in 11. Diabetes was present in 44%. In subjects with eGFR >60, warfarin use was associated with faster progression of BAC compared to controls: 10.0 (3.8-17); n=36 vs. 2.6 (0.8-7.0); n=58, p=0.002. A similar effect was seen in ESRD but resulted in much higher rates: 46.9 (31-183); n=11 vs. 15.2 (7-52); n=32, p=0.025. Warfarin’s effect was not augmented in patients with CKD (eGFR 17-58) or in diabetics vs. non-diabetics. Mammograms before or after warfarin use were available in 11 and 13 patients. BAC rate increased after starting warfarin (13.8 [7.8-39] vs. 2.1 [0.3-3.9]; p=0.01) and slowed, but not significantly, after stopping warfarin (1.9 [-7.4-6-8] vs. 8.8 [1.3-10]; p=0.11).

Conclusion

Warfarin accelerates progression of medial arterial calcification. This effect is magnified in ESRD, resulting in marked increases in calcification in this population. These data suggest that warfarin should be used with caution in ESRD, particularly in patients with extensive vascular calcification.