Study Evaluates Changes in Exercise Capacity After TAVR
June 19, 2017—A study published online ahead of print by Omar Abdul-Jawad Altisent, MD, et al in Circulation investigated the predictors of and association with clinical outcomes of the changes in exercise capacity after transcatheter aortic valve replacement (TAVR). The investigators describe these changes between baseline and 6-months after TAVR, and ascertain factors associated with a lack of improvement in exercise capacity after TAVR.
As summarized in Circulation, a total of 305 patients (mean age, 79 ± 9 years; 44% men; Society of Thoracic Surgery score, 6.7 ± 4.2%) undergoing TAVR completed both baseline and follow-up exercise capacity assessments at 6 months after TAVR. Exercise capacity was evaluated by the 6-minute walk test (6MWT).
Clinical outcomes were compared between patients displaying greater than (n = 152; improving group) versus lesser than (n = 153; nonimproving group) the median percentage change in distance walked between baseline and 6-month follow-up examinations. The primary outcome measure was clinical event rates, measured from the 6-month post-TAVR period onward. Further dichotomization according to baseline 6MWT distance (less than vs greater than median walking distance; or "slow walker" vs "fast walker") was also assessed.
The mean overall distances walked before and after TAVR (6 months after TAVR) were 204 ± 119 and 263 ± 116 meters, respectively (Δ6MWT= 60 ± 106 meters), with 219 (72%) patients demonstrating an increase in their walking distance (median increase of the entire population, 20% [interquartile range, 0%–80%]).
Factors independently correlated with reduced exercise capacity improvement included a range of baseline clinical characteristics (older age, female sex, chronic obstructive pulmonary disease; all, P < .05), periprocedural major or life-threatening bleeding (P = .009), and new-onset anemia at 6 months after TAVR (P = .009).
Failure to improve the 6MWT distance by at least 20% was independently associated with all-cause death (P = .002) and cardiovascular death or rehospitalization for cardiovascular causes (P = .001). Baseline slow walkers who were able to improve the 6MWT distance presented with significantly better outcomes than nonimprovers (all cause of death, P = .01; cardiovascular endpoint, P = .001).
The investigators concluded that approximately one-third of patients undergoing TAVR failed to improve their exercise capacity after the procedure. The lack of functional improvement after TAVR was predicted by a mix of baseline and periprocedural factors translating into poorer clinical outcomes. These results suggest that systematically implementing exercise capacity assessment before and after TAVR may help to improve patient risk stratification, noted the investigators in Circulation.