Noninvasive prediction of pre-capillary pulmonary hypertension (PH) component in patients with post-capillary PH

Abstract

Pulmonary hypertension (PH) is a common situation in patients with cardiovascular risk factors and heart failure with preserved ejection fraction (HFpEF). Make the difference between isolated post-capillary PH (IpcPH), combined pcPH (CpcPH) or isolated pre-capillary PH prior to right heart catheterization (RHC) is challenging. However, only pre-capillary PH may benefit from pulmonary arterial hypertension (PAH)-specific therapy. Identify noninvasive parameters that can predict a precapillary component in these patients. Patients with a RHC-confirmed diagnostic of IpcPH or CpcPH [mean pulmonary artery pressure (mPAP) ≥ 20 mmHg, PA wedge pressure (PAWP) > 15 mmHg and pulmonary vascular resistance (PVR) < 3 WU or ≥ 3 WU, respectively] or PAH (mPAP ≥ 20 mmHg, PAWP ≤ 15 mmHg, PVR ≥ 3 WU) and a simultaneous clinical and biological assessment, echocardiography, pulmonary function tests and arterial blood gases, were retrospectively included (discovery cohort). Those with a left ventricular ejection fraction < 50% were excluded. Multivariable logistic regression analysis was used to identify variables associated with a precapillary component and ROC analysis to determine associated thresholds. Based on these results, an algorithm was built and externally validated (validation cohort). In all, 154 patients were included in the discovery cohort: 51 IpcPH, 51 CpcPH and 52 PAH. Median age was 66 years, 62% were female. Multivariable logistic regression and ROC analyses determined a diffusing capacity of the lung for carbon monoxide (DLCO) < 63% of predicted and the ratio of echocardiography-derived tricuspid annular plane systolic excursion and pulmonary arterial systolic pressure (TAPSE/PASP) < 0.37 mm/mmHg as associated with CpcPH compared to IpcPH whereas LVEF ≤ 60% and left atrial dilatation as associated with CpcPH compared to PAH. An algorithm with high sensitivity and negative predictive value to avoid misclassification of patients with pre-capillary PH component in both discovery and validation cohorts is provided (Fig. 1). DLCO and TAPSE/PASP can accurately predict the presence of a precapillary component in patients with suspected PH in HFpEF. The externally validated algorithm may help physicians in the decision-making in case of PH suspicious in those patients.