Trans-catheter Aortic Valve Implantation (TAVI) is a well-established procedure in severe aortic stenosis with high surgical risk. However an understanding of the longer-term haemodynamic flow profile of these valves is limited, as assessed by echo parameters. This study aims to collate several key echocardiographic parameters over mid term follow up and highlight incidence rates of valvular degeneration.Methods
49 consecutive post TAVI patients seen within the Papworth physiologist-led valve service underwent retrospective analysis performed using standard 2D/Doppler-derived echo data. Data was compared during three follow up intervals (FU1 – 3 months; FU2 – 1 year; FU3 – 2 years) and between different TAVI sizes (23, 26 and 29 mm).Results
Data was analysed in all 49 patients, 26 patients reached FU3 (53%), with a total mortality rate of 8%. The majority had Sapien XT valves implanted (Sapien – 8; SapienXT – 34; Sapien3 – 7). Mean prosthetic valve Doppler measurements were similar from FU1 to FU3 – MPG (11.5±7.2; 12.1±7.3; 13.3±9 FU1-3 respectively), AVA (1.70±0.59; 1.61±0.50; 1.69±0.51) (p=>0.05), whilst LVEF showed significance between FU2-FU3 (51%–54%; p=0.04). Secondary analysis comparing different valve sizes indicated that the smaller valve size (23 mm) had slightly higher peak/mean valve gradients and lower aortic valve area (AVA), AVA index and Dimensionless Index. At FU1, the incidence of paravalvular leak (PVL) was 53%; although significant PVL (moderate) was less than 16%. Progression of PVL was noted from FU1 to FU3 only in 3%. Within valve sizes, 29 mm valves showed the greatest increase in PVL during follow up (FU1 10%-FU3 21%). 3 patients (6%), developed progressive obstructive valve parameters suggesting possible early valve thrombosis; all three showing improvement in these parameters towards baseline following commencement of oral anticoagulation.Conclusion
Our data shows a range of traditional prosthetic valve Doppler values which may be used as a guide to assess different TAVI valve types/sizes. It highlights rates of significant valvular degeneration over midterm follow up. Further studies with larger sample sizes are needed to further assess the validity of these findings.