Abstract 4118724: Validity of a NYHA Classification Guide with Six Minute Walk Test Outcomes

Background: The New York Heart Association (NYHA) classification is a subjective tool that is commonly used in clinical practice to assess symptoms and functional capacity of patients with heart failure (HF). Correct assignment of NYHA is essential to facilitate evidence-based management. Research Question: What is the validity of the CLASS-HF Guide compared to the 6-minute walk test (6MWT)? Purpose: To examine the validity of the new investigator-developed CLASS-HF guide to assist in appropriate assignment of NYHA Class relative to the 6MWT. Methods: A multi-site, cross-sectional study in three cardiology clinical sites (two specializing in HF) recruited 103 patients in various classes and stages of HF. Providers assigned patients their NYHA Classification using the CLASS-HF guide. Patients then performed the 6MWT with test staff blinded to the assigned NYHA class. Exertion, dyspnea, and walk distance were captured post-test. The validity of the guide-assisted classification was then examined for convergent validity with 6MWT outcomes. Data analysis was performed with correlations, ANOVA, and multivariable regression. Results: Of the 103 total participants, 65.1% were male, 18.4% were non-White, with an average age of 66.0 ± 15.5 years old. A little less than one-third (30.1%) had HFpEF (LVEF ≥ 50%). Provider-assigned NYHA Class was 22.3% I, 38.8% II, 35.0% III and 3.9% IV. The average distance walked during the 6MWT by class was: 367.1 ± 85.6 m for I, 343.7 ± 104.7 m for II, 261.6 ± 73.9 m for III, and 184.6 ± 114.0 m for IV. Convergent validity of NYHA class with Borg exertion (Spearman’s r = .546, p < .001) and dyspnea ( r = .504, p < .001) was strong. A statistically significant inverse correlation was found between NYHA assigned class and meters walked during the 6MWT ( r = -.469, p < .001), with significant mean differences (ANOVA F (3,99) = 10.72, p < .001) in distance walked for: NYHA Class I vs. III ( md = 105.5 m), I vs. IV ( md = 182.6 m), II vs. III ( md = 82.1 m), II vs. IV ( md = 159.2 m). Increasing NYHA class remained significantly associated with lower 6MWT distance ( F (3,90)=5.22, p = .002) in multivariable regression (Adj. R -squared= .575) controlling for age, sex, race/ethnicity, diagnosis, site, Borg exertion and dyspnea, and 6MWT stopping/pausing. Conclusion: Validity evidence was found for NYHA class assignment after use of the CLASS-HF guide with respect to 6MWT distance and post-test perceived exertion and dyspnea.