TRENDS IN TRANSVALVULAR GRADIENTS OVER TIME IN PATIENTS RECEIVING TRANSCATHETER VALVES

The standard of care for patients with aortic stenosis has evolved significantly in recent years with transcatheter aortic valve implantation (TAVR) shown to be a safe alternative to surgical aortic valve replacement (SAVR). Concerns remain as to the durability of TAVR valves and factors that may affect that durability. The objective of this study was to look at valve performance using echocardiography to assess for early structural valve deterioration.

All patients undergoing successful TAVR implantation between 2010 and 2018 were included in the study. Standard follow-up echocardiograms were performed before the procedure in addition to immediately post procedure and at: 6 weeks, 6 months, 1 year, and every year subsequently. Structural valve deterioration or failure was defined as a mean aortic valve gradient of >20mmHg after implantation. Using this approach, we divided patients into 2 groups: no evidence of valve deterioration versus any evidence of valve deterioration by ECHO. A total of 406 patients were included with balloon expandable (n=335) and self-expandable valves (n=57). Valve deterioration defined as a mean gradient >20mmHg was observed in 82 patients at any point during follow-up. Risk factors associated with valve deterioration were increased BMI (p=0.004), previous prosthetic valve (p=0.0001), older age (p=0.02), and female sex (p=0.02). Valves that developed mean gradients over 20mmHg were more likely to have had higher pre-TAVR gradients (p=0.007). Failure rates were low early after procedure (8% of patients). The relative failure rate increased to 24% of patients by year three. In patients showing gradients >20mmHg gradients appears to gradually increase as shown in the figure below. Even though there is variance in the initial year among valves (p=0.53), at two years and every year subsequently, there is no significant difference in valve gradient between self-expanding and balloon-expanding valves.

Our data demonstrates that TAVR valves provide a significant reduction in mean gradient across the aortic valve after deployment. Using follow-up echocardiography, we were able to demonstrate that some patients develop increasing mean gradients over time with up to 24% of patients by 3-year follow-up having some early structural valve deterioration. We identified several factors that were associated with higher gradients at follow-up and may warrant closer follow-up.