Abstract 12910: Exercise Hemodynamics Unmasks Stage C Heart Failure With Preserved Ejection Fraction and Impaired Peripheral Oxygen Extraction in Stage A/B Patients in a Safety-Net Center

Abstract

Introduction: There is a gap in research evaluating hemodynamics and impaired peripheral oxygen extraction in Stage A/B HFpEF in diverse groups. We sought to characterize the prevalence of impaired cardiac/peripheral profiles in Stage A/B HFpEF at Boston Medical Center. Hypothesis: We hypothesize both abnormal cardiac and peripheral profiles will be unmasked in exercising Stage A/B HFpEF patients. Methods: Invasive cardiopulmonary exercise testing (iCPET) was performed in 30 individuals with Stage A/B HFpEF. Significant valvular or pulmonary disease were excluded. Criteria for an impaired cardiac profile, with reclassification to Stage C, included exercise PCWP ≥ 25 mmHg or ΔPCWP/ΔCO slope > 2 mmHg/L/min. An impaired peripheral profile was defined as O 2 extraction ratio (peak arterio-venous oxygen saturation difference)/ (1.34*rest hemoglobin*rest arterial O 2 saturation) < 50%. With an approved IRB, the analysis was conducted in R. Results: Cohort clinical data shown in Table with 47% non-white and 57% female patients. Exercise unmasked Stage C HFpEF in 23 (77%) of cases; 17% had an impaired peripheral profile (O 2 extraction ratio 43 ± 7) and 10% (3 out of 30 patients) had concomitant impaired cardiac and peripheral profiles. Both cardiac and peripheral metrics correlated to metabolic parameters: peak oxygen consumption correlated to PCWP (rho -0.52, p<0.004) and extraction ratio correlated to oxygen-uptake efficiency slope (rho 0.40, p=0.029). Conclusions: In our diverse cohort, a significant proportion of Stage A/B patients reclassified to Stage C HFpEF via invasive exercise testing; abnormal peripheral profiles were also noted. Impaired cardiac and peripheral profile metrics were related to metabolic parameters. Broader implementation of iCPET in early disease stages and attention to both cardiac and peripheral profiles in diverse populations will guide further HFpEF research in novel mechanisms and therapeutics.