RHC Still Recommended Over Echocardiography for Detecting COPD-PH

Echocardiography has high specificity in the diagnosis of pulmonary hypertension (PH) in patients with advanced chronic obstructive pulmonary disease (COPD); however, it has low specificity for detecting PH in these patients, according to a recent study published in The American Journal of the Medical Sciences.

Detecting PH in patients with COPD is critical. Patients with COPD combined with PH carry increased risks for hospitalizations, mortality, and other exacerbations, and their PH status can influence candidacy for lung transplantation.

Holding Lungs | image credit: Katerina - stock.adobe.com

Right heart catheterization (RHC) is the typical approach for diagnosing PH, but the use of echocardiography could provide lots of benefits to patients. Comparatively, echocardiography is less expensive and invasive, and performs well in screening a patient’s pulmonary arterial pressure (PAP); however, the efficacy of this approach in identifying PH in patients with COPD is not sufficiently studied. Furthermore, at present RHC is relied upon for multiple transplant criteria including the management of transplant listing, identification and treatment of left-sided heart disease, as well as decision-making for single or double lung transplants. To address this gap, researchers conducted a study to evaluate the usefulness of echocardiography as a less-invasive diagnostic tool for PH in patients with COPD.

Patients with COPD being assessed for lung transplantation who also underwent RHC for PH diagnosis were evaluated between January 2011 and May 2019. Echocardiograms were performed at a median of 3 days from the time of RHC, with the majority occurring beforehand (76%). Individuals were classified as having low, intermediate, or high probability of PH according to their tricuspid regurgitation velocity (TVR) and the presence of echocardiographic evidence of PH. Echocardiographic criteria for PH included at least 2 of the following: detection of a right/left ventricle basal diameter ratio above 1, interventricular septum flattening, right ventricle outflow doppler acceleration time under 105 m/s, mid-systolic notching, or early diastolic pulmonary regurgitation velocity above 2.2 m/s^-1.

A total of 111 patients with severe COPD (defined according to the 6th World Symposium of Pulmonary Hypertension) who received RHC were evaluated. Of these 111, 82 patients were identified with COPD-PH (74%). Overall, patients had a mean PAP (mPAP) of 30.3 mm Hg, systolic PAP (sPAP) of 45.8 mm Hg, diastolic PAP (dPAP) of 21.8 mm Hg, pulmonary vascular resistance (PVR) of 4.0 mm Hg, diastolic pulmonary gradient (DPG) of 8.5 mm Hg, right arterial pressure (RAP) of 9.7 mm Hg, and pulmonary capillary wedge pressure (PCWP) of 13.5 mm Hg. Those with COPD-PH were noted to have significantly higher PAP levels compared to those without.

According to the echocardiographic criteria, 20 patients (18%) had a high likelihood for PH, 20 (18%) had intermediate, and 71 (64%) had low. In these cases, the sensitivity, specificity, positive predictive, and negative predictive values for echocardiography diagnosing COPD-PH were 43%, 83%, 88%, and 34%, respectively. Additionally, for the diagnosis of COPD–severe PH, these values were 67%, 75%, 50%, and 86%.

In light of their findings, the authors note that the echocardiography’s high specificity and positive predictive values demonstrate its value in the diagnosis of COPD-PH; however, it exhibited limited sensitivity for ruling out COPD-PH and its efficacy was impacted by the presence of significant hyperinflation or sever emphysema in these patients. The authors conclude by mentioning their results were not consistent with recommendations for identifying COPD-PH with noninvasive methods for advanced COPD; therefore, pretransplant RHC should still be considered.

Reference

Younis M, Al-Antary N, Dalbah R, et al. Echocardiography and pulmonary hypertension in patients with chronic obstructive pulmonary disease undergoing lung transplantation evaluation. Am J Med Sci. Published online November 13, 2023. doi:10.1016/j.amjms.2023.11.006