Abstract 3569: Subclinical Pulmonary Vascular Changes Occur Without Pulmonary Hypertension or Right Ventricular Dysfunction in Moderate to Severe Chronic Obstructive Pulmonary Disease
Introduction. Raised pulmonary artery pressure (PAP), pulmonary vascular resistance (PVR) and right ventricular dysfunction (RVD) are common in end stage chronic obstructive pulmonary disease (COPD), but their prevalence in pts with less severe COPD remains unclear. Methods. Sequential respiratory function tests (RFT) and transthoracic echocardiograms (TTE) were performed in 137 pts with COPD and 30 age-matched controls. COPD was defined according to GOLD guidelines. TTE were analysed for 2D parameters (chamber size, left ventricular EF) and Doppler parameters (TR grade and maximum velocity, RVOT time velocity integral and maximum velocity), and PVR was calculated from the TR maximum velocity and RVOT TVI. RVD was assessed by tissue Doppler. Pts with more than mild valvular regurgitation or stenosis were excluded. Comparison of means was made by independent-samples t-test. Results. There were no differences in left and right atrial size, left ventricular filling pressures or left ventricular ejection fraction between groups. Table 1⇓ compares RV parameters for both groups; despite the lack of difference in TR velocity, peak PAP and right ventricular stroke volume (RVOT TVI), the COPD group displayed increased PVR. The incidence of increased PVR in the COPD group was 60%, with no differences between tertiles of COPD severity. RV systolic function was similar between COPD and normals.
Conclusion. In ambulatory patients with moderate to severe COPD and normal pulmonary pressures, increased PVR is seen in the absence of RVD. Subclinical increases in PVR are common and do not correlate with air flow limitation severity in this group. Increased PVR may be a potential therapeutic target before the development of pulmonary hypertension and RV dysfunction.