The association of bisphosphonates, calcium levels and PTH levels with bioprosthetic aortic valve degeneration

Abstract

Background: Bioprosthetic aortic valve (bAV) degeneration represents a major concern following aortic valve replacement (AVR). The association of bisphosphonates, serum calcium and serum parathyroid hormone (PTH) with native AV degeneration have been studied extensively. However, their association with structural valve degeneration (SVD) is yet to be elucidated.

Methods: Patients who underwent AVR and had a baseline transthoracic echocardiogram (TTE) and at least one follow-up TTE spaced three months apart were included. SVD diagnosis was made according to American Society of Echocardiography guidelines. Patients' exposure to bisphosphonates and serum calcium and PTH levels were collected. A cutoff of 10.2 mg/dL for calcium and 65 pg/mL for PTH were used, respectively, to define pathological thresholds. Multivariable Cox proportional hazards regression models were built to evaluate the association between predictors and SVD.

Results: Overall, 2002 patients were included, of whom 214 (10.7 %) had SVD, with median degeneration time of 4 (IQR: 1.9, 6.1) years. Among them, reintervention occurred in 82 (4.1 %) without significant differences according to bisphosphonate use (Log Rank p = 0.300), elevated PTH or calcium levels (Log Rank p = 0.702 and p = 0.703, respectively). In the multivariate analysis, neither bisphosphonates use (HR: 0.95, 95 % CI: 0.56-1.60; p = 0.862), elevated calcium levels >10.2 mg/dL (HR: 0.74, 95 % CI: 0.31-1.72; p = 0.489), nor elevated PTH levels >65 pg/mL (HR: 1.91, 95 % CI: 0.99-3.68; p = 0.052) was associated with SVD.

Conclusions: The use of bisphosphonates, elevated serum calcium levels and elevated serum PTH levels were not associated with SVD nor with reintervention on the bAV.

Keywords: Bioprosthetic aortic valve; Bisphosphonate; Calcium; PTH; Structural valve degeneration.