Evaluation of OPN as a Marker to Predict Adverse Outcomes after Aortic Valve Replacement

Objectives: Osteopontin (OPN), a pro-inflammatory glycoprotein expressed in various cell types, plays both an important role in myocardial remodeling and also regulates calcium deposition by osteoblasts. In patients with calcific aortic valve disease (CAVD) circulating OPN levels are elevated as compared with healthy controls. The aim of this study was to correlate OPN plasma levels with demographic and echocardiographic parameters and evaluate a prognostic value for risk stratification in patients undergoing aortic valve replacement (AVR).

Methods: Patients undergoing AVR with or without coronary artery bypass grafting (CABG) and fulfilling several inclusion and exclusion criteria were enrolled (n = 152, 86 male, 72.4 ± 7.7 years) from 07/2015–08/2016. Peripheral blood was sampled at two defined time points (t1=pre-operative [pre-OP], t2=3 months post-operative [pOP]). Plasma OPN levels were measured with ELISA.

Results: Patients were divided into two groups depending on surgical procedure (G1: isolated AVR, n = 83; G2: AVR+CABG, n = 69). In both groups OPN levels increased (p < 0.01) from t1 (G1:173.4 ng/ml; G2:211.3 ng/ml) to t2 (G1:216.4 ng/ml; G2:269.1 ng/ml) with higher levels in G2 than in G1 at both time points (p < 0.01). There was no correlation between OPN levels at t1 and demographic parameters (age and body mass index) as well as ejection fraction (EF) or pre-OP effective orifice area (EOA). A positive correlation was detected in G1 between OPN and mean pressure gradient (mpg; p < 0.05) and shear stress (mpg/left ventricular EF; p < 0.05), while a negative correlation was perceived in G2 for both mpg (p < 0.01) as well as shear stress (p < 0.05). A total of 6 patients deceased till 3 month follow-up (G1: 0; G2: 6). OPN-levels at t1 in deceased patients (354.4 ng/ml) were significantly (p < 0.01) higher than in alive patients (202.17 ng/ml).

Conclusion: In this clinical series, distinct differences in OPN levels between patients undergoing AVR and AVR + CABG were detected with a significant correlation with several echocardiographic parameters. OPN levels increased significantly after surgery, which indicates that myocardial remodeling is more pronounced. Moreover, higher OPN levels could suggest a higher risk for adverse outcomes. Further studies should focus on the evaluation of OPN as potential marker for adverse outcomes, especially in patients undergoing AVR and CABG.