6-Minute walk test predicts prolonged hospitalization in patients undergoing transcatheter mitral valve repair by MitraClip

Background: The 6-minute walk test (6MWT) is a simple functional test that can predict exercise capacity and is widely employed to assess treatment outcomes. Although mortality with transcatheter mitral valve repair (TMVr) using the MitraClip (Abbott Vascular, Menlo Park, CA) is significantly less than for open mitral valve surgery in high-risk patients, identifying which patient will benefit the most from TMVr remains a concern. There are limited prognostic metrics guiding patient selection and, no studies have reported relationship between prolonged hospitalization and 6MWT. This study aimed to determine if the 6MWT can predict prolonged hospitalization in patients undergoing TMVr by MitraClip. Methods: We retrospectively reviewed 162 patients undergoing 6MWT before TMVr. Patients were divided into three groups according to the 6MWT distance (6MWTD) using the median (6MWTD >= 219 m, 6MWTD <219 m, and Unable to Walk). Multivariate logistic regression model was applied to select the demographic characteristics that were associated with the prolonged hospitalization defined as total length of stay >= 4 days in the study. Results: We found that 6MWT (odds ratio 3.64, 95% confidence interval 2.03-6.52, P<0.001) was independently associated with prolonged hospitalization after adjustment in multivariate analysis. Area under the curve of 6MWT for predicting prolonged hospitalization was 0.79 (95% confidence interval 0.72-0.85). Conclusions: Our study demonstrates that 6MWT was independently associated with prolonged hospitalization in patients with TMVr, and has a good discriminatory performance for predicting prolonged hospitalization.