Pre-Procedural 6-Min Walk Test as a Mortality Predictor in Patients Undergoing Transcatheter Mitral Valve Repair

Incremental prognostic value of functional impairment assessed by 6-min walking test for the prediction of mortality in heart failure

Natriuretic peptides (NP) are recognized as the most powerful predictors of adverse outcomes in heart failure (HF). We hypothesized that a measure of functional limitation, as assessed by 6-min walking test (6MWT), would improve the accuracy of a prognostic model incorporating a NP. This was a multicenter observational retrospective study. We studied the prognostic value of severe functional impairment (SFI), defined as the inability to perform a 6MWT or a distance walked during a 6MWT < 300 m, in 1696 patients with HF admitted to cardiac rehabilitation. The primary outcome was 1-year all-cause mortality. After adjusting for the baseline multivariable risk model-including age, sex, systolic blood pressure, anemia, renal dysfunction, sodium level, and NT-proBNP-or for the MAGGIC score, SFI had an odds ratio of 2.58 (95% CI 1.72-3.88; p < 0.001) and 3.12 (95% CI 2.16-4.52; p < 0.001), respectively. Adding SFI to the baseline risk model or the MAGGIC score yielded a significant improvement in discrimination and risk classification. Our data suggest that a simple, 6MWT-derived measure of SFI is a strong predictor of death and provide incremental prognostic information over well-established risk markers in HF, including NP, and the MAGGIC score.

Prognostic value of preprocedural 6-min walk test in patients undergoing transcatheter mitral valve repair-insights from the German transcatheter mitral valve interventions registry

AIMS

The 6-min walk test (6 MWT) has been established as an important tool for functional assessment in heart failure patients. However, its prognostic impact on the outcome in subjects with mitral regurgitation undergoing transcatheter mitral valve repair is unknown.

METHODS

This present work represents a sub-analysis of the German, prospective, multicenter, Transcatheter Mitral Valve Interventions (TRAMI) registry. Of the main study cohort (n = 828) 326 patients underwent 6 MWT prior to the procedure. Patients were assigned to two groups depending on the preprocedural 6 MWT distance using the median (< 200 m [group 1] vs. ≥ 200 m [group 2]).

RESULTS

No differences regarding procedural success (97 vs. 96%; p = 0.71) and 30-day mortality (3 vs. 4%; p = 0.96) were observed between the groups. With regards to 1-year outcome, patients with a walking distance < 200 m had higher all-cause mortality (26 vs. 14%; p = 0.013) as compared to those with a 6 MWT distance 200 m. After adjustment of baseline risk factors, 6 MWT distance < 200 m still showed a strong trend towards increased 1-year all-cause mortality (HR 1.63, 95% confidence interval 0.96-2.76; p = 0.071).

CONCLUSIONS

In the present study preprocedural 6 MWT distance < 200 m showed a strong trend towards increased 1-year mortality in patients undergoing MitraClip implantation.