Background: Aortic valve stenosis is the most frequent valvular defect characterized by increased inflammation, fibrosis, and calcification of the valves leading to seriously reduced exercise performance and efficiency. TAVI is increasingly used to restore proper aortic valve function. However, there are just a few limited reports about the actual improvements in cardiometabolic fitness (CMF) and physical performance after TAVI. Therefore, we wanted to quantify these improvements by using the 6 min walking test (6MWT) combined with assessing resting (REE) and post 6MWT exercise (AEE) energy expenditure before and after TAVI.

Methods: Before and six months after TAVI we measured anthropometric parameters, including body composition (bioimpedance analysis), various blood parameters, blood pressure and heart rate. Patients performed also a 6MWT after an 12h overnight fast combined with measuring oxygen consumption (V̇O₂) and carbon dioxide production (V̇CO₂) by indirect calorimetry (canopy system, supine position) in order to calculate REE and AEE immediately after completing the 6MWT as well as corresponding carbohydrate (COX) and fat oxidation (FOX) rates.

Results: We recruited 23 heart failure patients (12 women) with aortic valve stenosis and additional co-morbidities. Age: 81±1 yrs.; BMI: 28.4±4.3 kg/m²; HFrEF n=3, HFmEF n=1, HFpEF n=19; NYHA II n=3, NYHA III n=19, NYHA IV n=1. Six months after TAVI, BMI and body composition was unchanged, systolic blood pressure was increased from 129±21 to 145±20 mmHg (n.s.). Blood glucose, insulin, cholesterol, HDL, LDL and triglycerides did not change significantly. NEFA were significantly reduced from 0.72±0.04 to 0.52±0.03 mmol/L (p<0.05) and creatinine, uric acid and urea were increased from 125±10 to 140±14 µmol/L, 389±16 to 422±17 µmol/L, and 7.5±0.6 to 9.4±0.8 mmol/L, respectively (all n.s.). CRP was significantly reduced from 10.2±2.6 to 5.1±1.8 mg/L and IL-6 from 9.7±1.1 to 6.3±0.7 pg/m (all p<0.05). TNFα was unchanged and NT-proBNP was reduced from 3660±625 to 1514±181 pg/mL. Nineteen patients completed the 6MWT after TAVI. Two of them were wheelchair-dependent before, but covered 225 and 121 m, respectively, after TAVI. Three of them covered a lower distance after TAVI (-50, -84 and -134 m, respectively). Overall, the distance covered during the 6MWT increased significantly from 257±32 to 315±30 m. BORG scale rating decreased from 13.9±0.4 to 12.7±0.5. Furthermore, patients with the lowest physical performance before benefitted the most after TAVI. REE and resting COX and FOX did not differ significantly before and after TAVI. AEE was slightly and corresponding COX significantly increased (from 17.2±1.9 to 22.6±2.9 g/h, p<0.05) after vs. before TAVI. Post 6MWT delta in COX correlated significantly with the increase in walking distance during the 6MWT.

Conclusion: CMF significantly improved after TAVI. However, the lower the CMF was before, the better the CMF was after TAVI. This might have practical and clinical significance.