Clinical significance and correlation of microRNA-21 expression in patients undergoing transcatheter aortic valve replacement

Background: Transcatheter aortic valve replacement (TAVR) is an increasingly common procedure for treating severe aortic stenosis. While cardiac biomarker elevation post-TAVR is common, its correlation with outcomes remains controversial. MicroRNAs (miRNAs) have emerged as potential biomarkers in cardiovascular diseases. This study aimed to assess the prognostic significance of various miRNAs on outcomes after TAVR to stratify high-risk patients for adverse outcomes. Methods: Consecutive patients undergoing transfemoral TAVR were prospectively enrolled. Blood samples were collected at baseline and 6 hours post-procedure. MiRNA levels, including miR-21, miR-1, and miR-210, were quantified using PCR. The relative quantification (RQ) was analyzed by the ΔΔCt method. The primary outcome was major adverse cardiovascular or cerebrovascular events (MACCE). Receiver operating characteristic curve analysis was performed to assess the correlation between miRNAs and MACCE. Results: Seventy-six patients were included in the study, with a mean age of 80.8 years. Nearly a quarter of patients experienced MACCE. RQ analysis of miR-21 showed moderate prognostic accuracy for predicting freedom from MACCE (R=0.61). An RQ of miR-21 cutoff value of 0.709 yielded a sensitivity of 71% and specificity of 56%. Patients experiencing a significant decrease in miR-21 levels (RQ <0.709), had significantly higher MACCE rates and 30-day mortality compared to those with a non-significant change in miR-21 levels (40% vs. 16%, p=0.025 and 12% vs. 0%, p=0.033, respectively). Conclusions: A significant decrease in miR-21 levels at 6 hours post-TAVR is associated with poor patient outcomes. MiR-21 may serve as a potential biomarker for risk stratification and personalized post-TAVR management.