Exercise Capacity in Patients With Severe Symptomatic Aortic Stenosis Before and Six Months After Transcatheter Aortic Valve Implantation

Few data exist on the use of the 6-minute walk test (6MWT) to measure the exercise capacity of patients with severe symptomatic aortic stenosis considered at very high surgical risk. The objectives of the present prospective study were (1) to determine the feasibility and safety of the 6MWT as a measure of exercise capacity before and after transcatheter aortic valve implantation (TAVI), and (2) to determine the clinical and hemodynamic parameters associated with the exercise capacity changes in such patients. A total of 64 patients (age 80 ± 8 years, logistic European System for Cardiac Operative Risk Evaluation score 21 ± 15%, Society of Thoracic Surgeonsʹ score 7.5 ± 3.9%) who had undergone successful TAVI were included. The 6MWT was performed within the month before TAVI and at the 6-month follow-up visit. The mean distance walked increased from 165.3 ± 79.7 to 231.7 ± 88.9 m (p <0.0001); however, up to 25% of the patients did not improve or even decreased their exercise capacity. After adjustment for the baseline distance walked, multilinear regression analysis showed that a greater degree of renal dysfunction, as evaluated by the serum creatinine levels (r2 = 0.05, p = 0.03), lower postprocedural hemoglobin values (r2 = 0.13, p = 0.0012), and a longer hospitalization length (r2 = 0.08, p = 0.007) were associated with lower improvement in exercise capacity. In conclusion, exercise capacity, as evaluated by the 6MWT, was very poor in patients with severe symptomatic aortic stenosis considered at very high surgical risk. TAVI was associated with a significant increase in exercise capacity, although no improvement was observed in 1/4 of the patients. A greater degree in renal dysfunction, lower postprocedural hemoglobin values, and longer hospitalization stay were predictors of lower improvement in exercise capacity after TAVI. These results suggest that the 6MWT might become an important tool as a part of the evaluation process for TAVI candidates.