Performance-based functional assessment of patients undergoing transcatheter aortic valve implantation

Background Very few data exist on the functional evaluation of patients with severe symptomatic aortic stenosis undergoing transcatheter aortic valve implantation (TAVI). The aims of this prospective study were (1) to evaluate the Duke Activity Status Index (DASI) as a measure of functional status pre-TAVI and post-TAVI, (2) to determine the clinical parameters associated with DASI changes after TAVI, and (3) to compare functional status as evaluated by DASI and the New York Heart Association (NYHA) class with exercise capacity as evaluated by the 6-minute walk test (6MWT) in such patients. Methods A total of 76 patients (80 +/- 8 years old) who underwent successful TAVI were included. All patients completed the DASI self-questionnaire at baseline and at 6 months after TAVI, and 46 patients also performed a 6MWT. Results The mean DASI increased from 10.3 +/- 5.4 to 16.3 +/- 8.3 at 6 months after TAVI (P < .0001). However, the DASI did not change or even decreased to some extent in 30% of patients after TAVI. Renal dysfunction as evaluated by the estimated glomerular filtration rate was identified as the independent predictor of DASI impairment after TAVI (OR 1.7 for each decrease in estimated glomerular filtration rate of 10 mL/min/1.73 m(2), 95% CI 1.3-2.3, P = .005). The mean distance walked increased from 165.9 +/- 77.6 to 211.8 +/- 78.7 m (P = .0001) at follow-up. The DASI showed a good correlation with the distance walked at baseline (r = 0.55, P < .0001) and at follow-up (r = 0.66, P < .0001). The NYHA class improved to some degree in all but 5 patients; however, the NYHA class did not correlate with the results of DASI and the 6MWT. Conclusions Transcatheter aortic valve implantation was associated with a significant increase in functional status at 6-month follow-up as evaluated by the DASI, although no improvement was observed in about one third of patients. The presence of baseline renal dysfunction better determined this lack of improvement in functional status. The DASI, but not the NYHA class, correlated with distance walked in the 6MWT. These results suggest that the DASI might become a useful tool for evaluating both candidates for and the impact of TAVI procedures. (Am Heart J 2011; 161: 726-34.)