Pulmonary hypertension is one of the factors contributing to exercise intolerance in chronic obstructive pulmonary disease (COPD). This contribution may be different in COPD caused by different sources of smoke. We studied pulmonary artery pressure(PAP) and its relationship with lung function tests in three groups of subjects with COPD of various causes.
We studied 65 patients with COPD with more than 10 years history of cigarette smoking (27 patients), baking (20 patients), or hubble-bubble(HB) smoking (18 patients). These groups were matched for age and body mass index. After complete history including assessment of exercise tolerance and physical examination, all subjects had spirometry, lung volume studies by body plethsmography (using Jaeger body plethysmograph provided by Jaeger, Germany), analysis of arterial blood gases, and echocardiography with assessment of systolic and diastolic PAPs. Correlation between PAPs and various parameters of lung function including FEV1% predicted and RV/TLC, and oxygen saturation were obtained. Analysis of data was done using ANOVA and spearman correlation with p < 0.05 considered statistically significant.
Mean PAPs( 30.17, 27.91 and 27.92 mmHg) were not significantly different in these three groups as were FEV1% predicted ( 52.4%, 61.2% and 54.9%) in these three groups of patients with history of smoking cigarettes, baking, of HB smoking, respectively. Even though there was a significant negative correlation between mean PAP and arterial oxygen saturation, there was such a correlation only in cigarette smoking group(r=-0.42; p = 0.03). On the other hand, there was no correlation between mean PAP and FEV1% predicted or RV/TLC in any of these groups.
There no significant correlation between reduction of FEV1 or hyperinflation and pulmonary arterial hypertension in any of these groups. However, there was a significant negative correlation between oxygen saturation and pulmonary artery pressure in cigarette smoking group only.
These results may imply different mechanisms for pulmonary arterial hypertension in COPD of different causes with possibly different structural changes underlying reduction of FEV1, arterial oxygen desaturation, and pulmonary arterial hypertension.
Khalil Ansarin, No Financial Disclosure Information; No Product/Research Disclosure Information