Carolina M.S. Messina

A haemodynamic study of pulmonary hypertension in chronic hypersensitivity pneumonitis

Chronic hypersensitivity pneumonitis is a common fibrotic interstitial lung disease. The prevalence of pulmonary hypertension diagnosed by right heart catheterisation and its cardiopulmonary function findings in patients with chronic hypersensitivity pneumonitis are unknown. Consecutive symptomatic patients with chronic hypersensitivity pneumonitis were prospectively evaluated. All patients were submitted to right heart catheterisation, pulmonary function testing, a 6-min walk test, echocardiography, blood gas determination and N-terminal pro-brain natriuretic peptide analyses. Nonhypoxaemic patients also underwent incremental cardiopulmonary exercise testing. 50 patients underwent right heart catheterisation; 25 (50%) of these had pulmonary hypertension and 22 (44%) had a pre-capillary haemodynamic pattern. The patients with pre-capillary pulmonary hypertension had lower forced vital capacity (mean±sd 50±17% versus 69±22% predicted, p<0.01), carbon monoxide diffusing capacity (37±12% versus 47±14% predicted, p<0.01), arterial oxygen tension (median (interquartile range) 59.0 (47.8–69.3) versus 73.0 (62.2–78.5) mmHg, p<0.01) and saturation after the 6-min walk test (78±8% versus 86±7%, p<0.01). In pre-capillary pulmonary hypertension, oxygen uptake was also lower at the anaerobic threshold (41±11% versus 50±8% predicted, p=0.04) and at peak exercise (12.8±1.6 versus 15.0±2.5 mL·kg−1·min−1, p=0.02). Pre-capillary pulmonary hypertension is common in symptomatic chronic hypersensitivity pneumonitis and is related to interstitial lung disease severity. Additionally, pulmonary hypertension is more prevalent in hypoxaemic patients with impaired lung function and exercise capacity. PH is common in chronic hypersensitivity pneumonitis and is related to interstitial lung disease severity http://ow.ly/uTXXx

Usefulness of pulmonary capillary wedge pressure as a correlate of left ventricular filling pressures in pulmonary arterial hypertension

BACKGROUND Pulmonary arterial hypertension (PAH) is characterized by a pulmonary capillary wedge pressure (PCWP) of ≤15 mm Hg, given a normal left ventricular filling pressure (LVFP). However, recent studies have shown that, in PAH patients, diagnosis based on PCWP can erroneously classify a significant number of patients compared with diagnosis based on left ventricular end-diastolic pressure (LVEDP). Therefore, we sought to compare the diagnostic accuracy of end-expiratory PCWP and LVEDP measurements in patients suspected of having pulmonary hypertension (PH). METHODS We reviewed the hemodynamic data from 122 patients suspected of having PH who underwent simultaneous right- and left-side heart catheterizations at a PH referral center from 2006 to 2011. RESULTS PH was diagnosed in 105 patients, 79% of whom (n = 83) showed a pre-capillary pattern according to the LVEDP measurement. Ninety percent of patients with PCWP ≤15 mm Hg were correctly classified as having pre-capillary PH. However, 39% of patients with a PCWP >15 mm Hg had LVEDP ≤15 mm Hg and would have been erroneously diagnosed with pulmonary venous hypertension based on their PCWP measurements alone. The sensitivity and specificity was 0.89 and 0.64, respectively. A Bland-Altman analysis of the PCWP and LVEDP measurements revealed a mean bias of 0.3 mm Hg with 95% limits of agreement of -7.2 to 7.8 mm Hg. CONCLUSIONS A PCWP ≤15 mm Hg was found to be a reliable indicator of normal LVFP in pre-capillary PH patients. When measured properly and analyzed in the clinical context, PCWP is a valuable tool for accurate diagnosis of PAH.

Clinical usefulness of end-tidal CO2 profiles during incremental exercise in patients with chronic thromboembolic pulmonary hypertension

INTRODUCTION Great ventilation to carbon dioxide output (ΔV˙E/ΔV˙CO2) and reduced end-tidal partial pressures for CO2 (PetCO2) during incremental exercise are hallmarks of chronic thromboembolic pulmonary hypertension (CTEPH) and idiopathic pulmonary arterial hypertension (IPAH). However, CTEPH is more likely to involve proximal arteries, which may lead to poorer right ventricle-pulmonary vascular coupling and worse gas exchange abnormalities. Therefore, abnormal PetCO2 profiles during exercise may be more prominent in patients with CTEPH and could be helpful to indicate disease severity. METHODS Seventy patients with CTEPH and 34 with IPAH underwent right heart catheterization and cardiopulmonary exercise testing. According to PetCO2 pattern during exercise, patients were classified as having an increase or stabilization in PetCO2 up to the gas exchange threshold (GET), an abrupt decrease in the rest-exercise transition or a progressive and slow decrease throughout exercise. A subgroup of patients with CTEPH underwent a constant work rate exercise test to obtain arterial blood samples during steady-state exercise. RESULTS Multivariate logistic regression analyses showed that progressive decreases in PetCO2 and SpO2 were better discriminative parameters than ΔV˙E/ΔV˙CO2 to distinguish CTEPH from IPAH. This pattern of PetCO2 was associated with worse functional impairment and greater reduction in PaCO2 during exercise. CONCLUSION Compared to patients with IPAH, patients with CTEPH present more impaired gas exchange during exercise, and PetCO2 abnormalities may be used to identify more clinically and hemodynamically severe cases.

Pulmonary haemodynamics and mortality in chronic hypersensitivity pneumonitis

Chronic hypersensitivity pneumonitis (CHP) is a common interstitial lung disease (ILD) frequently associated with lung fibrosis [1]. Among patients with CHP, the degree of pulmonary function impairment and the extent of fibrosis are known predictors of mortality [2, 3]. In other forms of ILD, such as idiopathic pulmonary fibrosis (IPF) and sarcoidosis, abnormal pulmonary haemodynamics measured during resting supine right heart catheterisation (RHC) are additionally associated with poor prognosis [4–7]. In CHP, however, the prognostic value of RHC is unknown. Indices of pulmonary vascular dysfunction are associated with mortality in chronic hypersensitivity pneumonitis http://ow.ly/1nwG30jwTSm

Inspiratory muscle weakness contributes to exertional dyspnea in chronic thromboembolic pulmonary hypertension

Determination of potentially-reversible factors contributing to exertional dyspnea remains an unmet clinical need in chronic thromboembolic pulmonary hypertension (CTEPH). Therefore, we aimed to evaluate the influence of inspiratory muscle weakness (IMW) on exercise capacity and dyspnea during effort in patients with CTEPH. We performed a prospective cross-sectional study that included thirty-nine consecutive patients with CTEPH (48 ± 15 yrs, 61% female) confirmed by right heart catheterization that underwent an incremental cardiopulmonary exercise test, 6-minute walk test and maximum inspiratory pressure (MIP) measurement. MIP < 70%pred was found in 46% of patients. On a multiple linear regression analysis, MIP was independently associated with 6MWD and V˙O2PEAK. Patients with MIP < 70% presented greater ΔV˙E/ΔV˙CO2 than those with MIP ≥ 70%. Additionally, they also presented stronger sensations of dyspnea throughout exercise, even when adjusted for ventilation. At rest and at different levels of exercise, mean inspiratory flow (VT/TI) was significantly higher in patients with MIP < 70%. In conclusion, IMW is associated with a rapid increase of dyspnea, higher inspiratory load and poor exercise capacity in patients with CTEPH.