Challenges of Classifying Stage B Heart Failure in a High-Risk Population

Background Stage B heart failure (SBHF) increases the risk of symptomatic HF. Current guideline criteria for SBHF lack sex and ethnic thresholding and cardiac magnetic resonance (CMR) imaging cut-offs. We aimed to assess the prevalence of SBHF in a large cohort of people with T2D and healthy controls, and propose a refined CMR definition for SBHF. Methods Sex and ethnic specific thresholds for imaging criteria were derived from 373 healthy controls, who underwent CMR cine imaging. The current definition for SBHF and refined criteria were applied to our prospectively recruited and intensively phenotyped cohort of asymptomatic people with T2D and no evidence of cardiovascular disease. The prevalence of SBHF by different definitions was calculated and patient characteristics, including exercise capacity, were compared between those classified as Stage A vs. B HF. Finally, the refined criteria were also applied to two historical cohorts with symptomatic cardiovascular disease: severe aortic stenosis (AS n=70) and HF with preserved Ejection Fraction (HFpEF n=136). Results A total of 423 people with T2D and a subset of 102 healthy controls who underwent echocardiography were prospectively recruited. Current guideline criteria classified 91% of those with T2D and 69% of the healthy controls as SBHF, suggesting a lack of specificity. Applying derived sex and ethnicity specific thresholds, combining echo and CMR measures, the prevalence of SBHF was reduced to 30% in those with T2D. Those with Stage B HF in the refined definition had lower exercise capacity than those with Stage A HF (percentage predicted maximal oxygen consumption 81 ± 16% vs 91 ± 20%, p< 0.001). Applying the refined definition to symptomatic AS and HFpEF participants classified 89% and 85% with abnormal cardiac remodelling. Conclusion Current guideline criteria for SBHF are non-specific and likely of limited value in clinical practice. Refining these criteria with sex- and ethnic-specific thresholds may improve identification of those at risk of developing symptomatic disease. Further research is required to validate these criteria.