Hypercholesterolemia is a risk factor for bioprosthetic valve calcification and explantation

Abstract 

Objective

There are pathophysiologic similarities between calcification and atherosclerosis. We wished to determine whether risk factors for atherosclerosis were linked to bioprosthetic valve calcification and dysfunction.

Methods

We performed a retrospective cohort study on 144 patients at a single institution who had bioprosthetic aortic or mitral valves removed, serum cholesterol levels recorded, and valve calcification assessed on the basis of hematoxylin and eosin staining and radiography of the valve. We also performed case-control analysis of a group of 66 patients whose tissue valves were explanted and compared them with an age- and position-matched group of 66 patients with similar duration of implantation. We also compared mean serum cholesterol levels.

Results

In the retrospective cohort study cholesterol (P = .035), younger age at implantation (P = .014), and coronary artery disease (P = .017) were linked to calcification of the valve by means of univariate analysis. In stepwise multiple regression analysis only the mean serum cholesterol level was linked to calcification (P = .02). Sex, hypertension, smoking, diabetes, and implant position were not linked to calcification. In the case-control analysis the mean serum cholesterol level of the explanted valve group was significantly higher (189 vs 163 mg/dL, P < .0001) than that of the group whose valves did not require explantation. For those whose serum cholesterol levels were greater than 200 mg/dL, the odds ratio was 3.9 (95% confidence interval, 1.7-8.9) for valve explantation.

Conclusions

Increased serum cholesterol level may be a risk factor for bioprosthetic valve calcification requiring explantation.

Keywords:  16, 35