Improved exercise tolerance, oxygen delivery and oxygen utilization after transcatheter aortic valve implantation for severe aortic stenosis

Abstract Background Transcatheter aortic valve implantation (TAVI) represents an effective therapeutic procedure, particularly in patients with severe aortic stenosis (AS). We hypothesized that the decreased afterload induced by TAVI would improve exercise capacity by enhancing oxygen uptake in working muscles. Methods A standardized exercise test was performed in patients with severe AS the day before TAVI and within five days thereafter. The main study endpoint was the workload (W) achieved during a 5-minute standardized exercise test. Using electrical cardiometry and near-infrared spectroscopy, we explored and compared the changes in cardiac index (CI) as well as muscular and cerebral tissue oximetry (mtSO2 and ctSO2) during the two exercise tests. Results Thirty patients completed the study protocol. Compared with the pre-TAVI period, patients achieved a higher median W after TAVI (316 Joules [interquartile range [IQR] 169 – 494] vs 190 Joules [131 – 301], p=0.002). Baseline CI increased from 2.5 l/min/m2 [2.1 – 2.9] to 2.9 l/min/m2 [2.5 – 3.2] (p=0.009) whereas end-exercise exercise CI increased from 4.5 l/min/m2 [3.4 – 5.3] to 4.7 l/min/m2 [3.4 – 6.4], (p=0.019). End-exercise ctSO2 increased from 70% [65 – 72] to 74% [66 – 78] and mtSO2 increased from 62% [58 – 65] to 71% [65 – 74] (p=0.046 and p Conclusions Early improvement of exercise capacity after TAVI is associated with increased CI and better oxygen utilization in the brain and the skeletal muscles.