Sensitivity of Doppler Echocardiography and Right Heart Catheterization in Evaluation of Pulmonary Artery Pressure in COPD Patients

Abstract

Background: There is still controversy about whether transthoracic echocardiography (TTE) can provide reliable estimations of pulmonary artery pressures (PAP). The primary endpoint of this study was to evaluate the correlation between TTE and right heart catheterization (RHC) in estimating systolic (SPAP) and mean (MPAP) pulmonary artery pressures. In patients with Chronic Obstructive Pulmonary Disease (COPD), lung hyperinflation and heart rotation frequently degrade ultrasound signal quality, making Doppler echocardiography less reliable than in the general population for estimating pulmonary hypertension (PH). While echocardiography remains a screening tool, invasive Right Heart Catheterization (RHC) is considered the definitive method to diagnose and categorize PH in COPD patients.

Methods: About 141 consecutive patients (average age 63.6±11.5 years; 84 women) with suspected or confirmed pulmonary hypertension (PH) were enrolled into this retrospective observational monocentric study. All patients underwent TTE and, within 3 hours, RHC. The correlation between TTE and RHC in estimating both SPAP and MPAP was retrospectively determined.

Results: Seventeen (17) of the patients were excluded due to insufficient TTE signal quality. Of the remaining 124 patients, 18 had no PH. There was moderate correlation between both SPAP and MPAP estimated by TTE and those assessed by RHC (r=0.65 and r=0.60, respectively). Bland-Altman analysis revealed a bias of –11.9 mmHg (with the 95% limits of agreement ranging –45.4 to +21.5 mmHg) for SPAP estimation and –4.6 mmHg (with the 95% limits of agreement ranging –27.9 to +18.8 mmHg) for MPAP estimation, suggesting a general overestimation of PAP by TTE. The main factors responsible for discrepancies between TTE and RHC were: female gender, arrhythmic cardiac electrical activity, systemic arterial hypertension, and diuretic treatment.

Conclusions: The study suggests that while TTE is a valuable tool for initial suspicion of pulmonary hypertension, it is not a substitute for RHC when an accurate diagnosis is required. The "moderate" correlation and wide limits of agreement mean that TTE may lead to "false positive" diagnoses of PH, particularly in hypertensive women with arrhythmias and is less reliable in COPD patients.