Introduction: Exercise right heart catheterization (RHC) is useful in the evaluation of unexplained dyspnea, particularly in diagnosing exercise-induced heart failure with preserved ejection fraction (HFpEF). Two diagnostic criteria are commonly utilized for supine exercise: pulmonary artery wedge pressure (PAWP) at peak exercise ≥25 mmHg, and multi-point slope of the PAWP/cardiac output (CO) ratio ≥2 mmHg*min/L. Given marked intrathoracic pressures swings that can occur during exercise, an additional major controversy exists regarding how to assess pressures regarding the respiratory cycle (end-expiratory versus averaged measures). We hypothesized that the PAWP/CO slope diagnostic criteria would be less impacted by differences in respiratory variation assessment than peak pressure criteria.
Methods: A single-center retrospective review of patients who underwent supine exercise RHC for unexplained dyspnea from July 2018 to August 2022 was performed. End-expiratory PAWP (PAWPexp) were manually assessed, and computer generated PAWP averaged over the respiratory cycle (PAWPave) were also collected. Related-Sample Cochran’s Q Test and Dunn post-hoc pairwise comparison with Bonferroni correction were used to determine differences in reclassification based on respiratory variation assessment.
Results: Seventy-seven patients were identified and had an average H2FpEF score of 3.58 ± 2.07. Using peak PAWPexp criteria, 42 patients (54.5%) met the criteria for HFpEF, whereas only 21 patients (27.3%) met the criteria by peak PAWPave, a net reclassification of 21 patients (p<0.001). When using the PAWPexp/CO slope >2 for diagnosis, 58 (75.3%) of the patients met the criteria, with reclassification of only 10 patients (48 patients, 62.3%) when using PAWPave/CO (p=0.960).
Conclusion: Diagnostic criteria for exercise-induced HFpEF lead to significant differences in the number of patients ultimately diagnosed with HFpEF. However, the PAWP/CO slope methodology reduces the diagnostic variation introduced by respiratory cycle assessment differences. 