The Gradient between Diastolic Pulmonary Arterial Pressure and Pulmonary Wedge Pressure Is Important in the Evaluation of Post-Capillary Pulmonary Hypertension

Abstract

Purpose To provide a description of post-capillary pulmonary hypertension (PH) patients and to evaluate the role of the gradient between diastolic pulmonary arterial pressure (dPAP) and pulmonary wedge pressure (Ppw) in the assessment of post-capillary PH. Methods and Materials We reviewed the clinical, echocardiographic and hemodynamic data of each patient assessed for pulmonary arterial hypertension (PAH) between January 2009 and June 2011 in our PH reference centre. Results 82 patients had right heart catheterization for suspected PAH. PH was confirmed in 68 patients. 27 (40%) had post-capillary PH: 2 had systolic left heart dysfunction, 25 had preserved left ejection fraction. The mean age of these 25 patients was 67 years. 10 (40%) were women. 21 (84%) had systemic hypertension, 11 (44%) had atrial fibrillation and 5 (20%) had ischemic cardiomyopathy. 13 (52%) were obese. 9 (36%) had metabolic syndrome. 19 (76%) had echocardiographic features of left diastolic dysfunction, the most frequent finding being left atrial enlargement. Mean value of mean PAP was 43mmHg and of Ppcw 21 mmHg. Only 3 patients had TPG ≤ 12 mmHg and all of them had a dPAP-Ppw gradient 12 mmHg. Among the 27 patients with group 2 PH, 12 (44%) had also a non cardiac pathology that could cause PAH (4 had chronic thromboembolic disease, 4 hypoxemic pneumopathy, 1 porto-pulmonary hypertension, 1 HIV infection, 1 chronic bronchitis, 1 sarcoidosis). 75% of these patients with left heart disease and another documented risk factor for PH had a dPAP-Pwp gradient > 5mmHg versus 8% of those without another documented risk factor (p-value 0.0075). Conclusions Post-capillary PH is frequent. In our cohort 85% post-capillary PH patients had out of proportion PH, among whom 52% had a non cardiac risk factor for PAH. The dPAP-Ppw gradient seems a better discriminator factor than TPG for the characterisation of post-capillary PH.