Improved Exercise Tolerance, Oxygen Delivery, and Oxygen Utilization After Transcatheter Aortic Valve Implantation for Severe Aortic Stenosis

BACKGROUND: Transcatheter aortic valve implantation (TAVI) represents an effective therapeutic procedure, particularly in patients with severe aortic stenosis. 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 aortic stenosis the day before TAVI and within 5 days thereafter. The main study endpoint was the workload 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, during the 2 exercise tests. RESULTS: Thirty patients completed the study protocol. Compared with the pre-TAVI period, patients achieved a higher median workload after TAVI (316 Joules [interquartile range {IQR}: 169–494] vs 190 Joules [IQR: 131–301], P = 0.002). Baseline CI increased from 2.5 l/min per m(2) (IQR: 2.1–2.9) to 2.9 l/min per m(2) (IQR: 2.5–3.2; P = 0.009), whereas CI at the end of the exercise test increased from 4.5 l/min per m(2) (IQR: 3.4–5.3) to 4.7 l/min per m(2) (3.4–6.4; P = 0.019). At the end of the exercise test, cerebral tissue oximetry increased from 70% (IQR: 65–72) to 74% (IQR: 66–78), and muscle tissue oximetry increased from 62% (IQR: 58–65) to 71% (65–74; P = 0.046 and P < 0.001, respectively). CONCLUSIONS: Early improvement of exercise capacity after TAVI is associated with increased CI and better oxygen utilization in the brain and skeletal muscles.