Abstract 14608: Impact of Phospho-Calcic Metabolism and Calcium Supplements on Bioprosthetic Valve Calcification Assessed by Computed Tomography
Background: Cusp calcification is the main mechanism leading to structural degeneration of bioprosthetic heart valves (BPVs). Recent studies suggest that BPV calcification is an active rather than passive process probably modulated by several mechanisms including lipid mediated inflammation and dysfunctional phospho-calcic metabolism. The objective of this prospective study was to identify the clinical and metabolic determinants of BPV calcification assessed by multi-detector computed tomography (CT).
Methods and results: Presence of BPV calcification was assessed by CT in 194 consecutive patients with an aortic BPV. Patients also underwent a clinical evaluation with a detailed record of medications, a Doppler-echocardiographic exam and a complete blood lipid and plasma phospho-calcic profile. Forty-six (46) pts (24%) had evidence of BPV calcification (cusp calcification score >0 mm3). Patients with BPV calcification had similar plasma levels of calcium (2.37±0.01mmol/l vs. 2.34 ±0.07mmol/l, p=0.1) and phosphorus (1.06± 0.15mmol/l vs. 1.02±0.15 mmol/l, p=0.1) but significantly higher calcium phosphorus product (2.55± 0.36 mmol2/l2 vs. 2.41 ±0.39 mmol2/l2, p=0.04) and prevalence of patient-prosthesis mismatch (17% vs. 7%, p=0.06). On multivariable analysis adjusted for age, gender, and time interval since BPV implantation, increased calcium-phosphorus product (OR=1.11, 95% CI: 1.01-1.23 per 1 unit; p=0.02) and the presence of patient-prosthesis-patient mismatch (OR=3.67, 95%CI: 1.25-10.6;p=0.01) were the strongest independent predictors of BPV calcification. Calcium supplement intake, age and female gender were independently associated with increased calcium phosphorus product.
Conclusion: This study is the first to assess the determinants of BPV calcification by CT and it demonstrates a strong independent association between higher calcium phosphorus product and increased risk of BPV calcification. Furthermore, this study reports that calcium supplements, which are extensively prescribed in elderly patients, are independently associated with higher calcium-phosphorus product. Further studies are needed to determine if calcium supplementation may directly contribute to BPV calcification.
- © 2013 by American Heart Association, Inc.