Hemodynamic evaluation of exercise pulmonary hypertension: a comparative analysis of diagnostic criteria

Introduction The hemodynamic study of exercise is a recognized diagnostic tool for patients with dyspnea of unknown origin. The ESC guidelines define exercise pulmonary hypertension (exPH) as a mean pulmonary artery pressure/cardiac output (ΔmPAP/ΔCO) slope > 3 mmHg/L/min between rest and peak exercise. However, this criterion contrasts with the 2017 ERS statement on exercise right heart catheterization (exRHC), which recommends using the multipoint slope approach. Furthermore, the multipoint pulmonary arterial wedge pressure/cardiac output (PAWP/CO) slope remains the gold standard for diagnosing heart failure with preserved ejection fraction. Despite these established criteria, inconsistencies persist across guidelines and studies regarding the optimal diagnostic approach for exPH. Objective To compare the diagnostic accuracy and classification concordance of the Multipoint and Delta slope criteria during exRHC. Methods A retrospective study was conducted on 68 patients (>18 years old) with dyspnea of unknown origin and suspected PH, excluding those with left heart disease or interstitial lung disease. Significant PH was ruled out in the baseline study before applying the exercise protocol (mPAP < 25mmHg, pulmonary vascular resistance < 3 Wood units, and PAWP ≤ 15mmHg). ExRHC was performed in a supine position using a cycle ergometer. Hemodynamic parameters, including mPAP, PAWP, and CO measured by thermodilution, were recorded at each exercise stage. Patients with fewer than three data points or missing pressure/CO values were excluded. An abnormal response was defined as a multipoint mPAP/CO slope > 3 mmHg/L/min and ΔmPAP/ΔCO > 3 mmHg/L/min between peak of exercise and rest. A postcapillary component was identified when the multipoint PAWP/CO slope or ΔPAWP/ΔCO exceeded 2 mmHg/L/min. Results A total of 68 patients were analyzed, with a mean age of 54.2 ± 15.2 years, and 38 (55.9%) were male. Baseline characteristics and hemodynamic values are summarized in table 1. The multipoint criterion obtained a mean mPAP/CO slope of 3.02 (95% CI: 2.66–3.37) mmHg/L/min and a mean PAWP/CO slope of 1.57 (1.34–1.81) mmHg/L/min. Using this method, patients were classified as follows: normal 38 (55.9%), pre-capillary exPH 16 (23.5%), isolated postcapillary exPH 3 (4.4%), and postcapillary exPH 11 (16.2%). The ΔmPAP/ΔCO slope resulted in a mean of 3.32 (95% CI: 2.93–3.70) mmHg/L/min, classifying patients as normal 34 (50.0%), pre-capillary exPH 16 (23.5%), postcapillary exPH 16 (23.5%), and isolated postcapillary exPH 2 (2.9%) (Figure 1). The kappa index for agreement between the multipoint and ΔmPAP/ΔCO criteria was 0.79 (95% CI: 0.65–0.94, p<0.001) for mPAP/CO and 0.76 (95% CI: 0.60–0.91, p<0.001) for PAWP/CO. Conclusion Both criteria have similar diagnostic concordance. However, the multipoint approach is more conservative and seems to offer a more detailed and accurate depiction of vascular resistance across the entire exercise duration.