Insulin-like growth factor binding protein 2 predicts course of concomitant right-ventricular dilation and tricuspid regurgitation after transcatheter edge-to-edge mitral valve repair
Authors: Groeger M , Hirsch K , Schneider L M , Rottbauer W , Markovic S , Kessler M 
Published: October 2024

Abstract

Aims
Right ventricular (RV) dilation and secondary tricuspid regurgitation (TR) are highly prevalent comorbidities in patients with mitral regurgitation and are associated with a worse prognosis. TR improvement after successful transcatheter edge-to-edge mitral valve repair (M-TEER) is reported regularly, however specific factors contributing to the recovery of RV function and TR after M-TEER are poorly understood. Particularly the role of serum biomarkers in this context is unclear. We aimed to identify specific biomarkers associated with the course of concomitant RV dilation and TR after M-TEER.

Methods and Results
We prospectively included 242 patients undergoing M-TEER at our center and obtained pre-procedural blood samples for biomarker analysis. A commercial multiplex protein assay (Cardiovascular III, Olink, Uppsala, Sweden) was used to quantify expression levels of 92 defined biomarkers. We then analyzed differences in biomarker expression between patients with and without right ventricular reverse remodeling (RVRR) as defined by improvement of concomitant TR by at least one grade and/or downsizing of the basal RV diameter of at least 10%.
242 patients were included in this analysis, 94 had no/mild concomitant TR at baseline, 148 had moderate/severe TR. RV diameters correlated with TR severity and were significantly larger in patients with moderate/severe TR. At baseline, expression of numerous cardiometabolic biomarkers was significantly higher in patients with moderate/severe TR. These included NT-proBNP (1.9-fold, p &lt; 0.001), matrix metalloproteinase 2 (1.4-fold, p &lt; 0.001) as well as insulin-like growth factor binding proteins 1 (1.7-fold, p &lt; 0.001), -2 (1.3-fold, p = 0.001) and -7 (1.4-fold, p &lt; 0.001).
Follow-up analysis was performed in patients with initial moderate/severe TR. The course of TR and RV dimensions three months after M-TEER could be assessed in 99 patients (56 with moderate TR, 43 with severe TR). RVRR had occurred in 50 patients (50.5%). Patients without RVRR had a higher prevalence of chronic pulmonary disease (24.5 vs. 2.2%, p &lt; 0.001). No further differences in clinical characteristics were found. Specifically, RV diameter, systolic pulmonary artery pressure (sPAP) and right-ventricular systolic function did not differ substantially between both groups. Strikingly however, the expression of insulin-like growth factor binding protein 2 (IGFBP-2) was significantly higher in patients, who did not develop RVRR (fold change 1.3 compared to patients with RVRR, p = 0.022). After adjustment for covariates IGFBP-2 was independently associated with absence of RVRR (Odds Ratio 2.078, 95% Confidence interval 1.108 – 3.897, p = 0.023).

Conclusions
In patients undergoing M-TEER with concomitant moderate or severe TR, numerous cardiometabolic biomarkers including IGFBP-2 are upregulated. Higher levels of IGFBP-2 at baseline are independently associated with persistent TR and/or RV dilation after M-TEER.