Six-minute walk distance uncovers high-risk HFrEF patients despite guideline-based assessment
M Chudy, P Lesny, E GoncalvesovaAbstract
Background
Current ESC guidelines identify a 6-minute walk distance (6MWD) of less than 300 meters as an indicator of poor prognosis in patients with heart failure. However, some patients with heart failure and severely reduced ejection fraction, despite having a high clinical risk of mortality, are still able to achieve longer walking distances.
Purpose
To evaluate the 1-year prognostic value of 6MWD and to identify the optimal cutoff for predicting 1-year mortality or LVAD implantation in HFrEF patients reffered to advance HF centre.
Methods
We prospectively followed 450 HFrEF patients (mean age 51.9±10.1 years; mean LVEF 25.9±6.6%; median NT-proBNP 1676 (731–3448) ng/l). Patients undergoing heart transplantation (HTx) were excluded to focus on the natural progression toward death or LVAD. The primary endpoint was a composite of 1-year all-cause mortality or LVAD implantation. Multivariable Cox regression and ROC analysis were used for prognostic modeling.
Results
A total of 43 events (9.6%) occurred within one year. Multivariable Cox regression identified 6MWD (per 50m increase, HR 0.77, 95% CI 0.67–0.89, p < 0.001), systolic blood pressure (HR 0.96, p=0.002), lveft ventricle ejection fraction (HR 0.92, p=0.014), and logNT-proBNP (HR 2.98, p=0.004) as independent predictors of the endpoint. ROC analysis identified 415 meters as the optimal 1-year prognostic threshold (AUC 0.73) in thease patient polulation. Importantly, one-year event rates were 22.9% in patients walking <300 m and remained substantial (17.5%) in those walking 300–415 m.
Conclusion
While the conventional 300m threshold identifies the highest-risk group, our data show that HFrEF patients walking between 300m and 415m remain at significant risk (17.3% 1-year event rate). The 6MWD remains a powerful, independent prognostic tool, but its interpretation should be more stringent in the HFrEF population, as the safety threshold may be closer to 415m than the currently recommended 300m.For image description, please refer to the figure legend and surrounding text.