Objective To investigate the change of N-terminal pro-B-type natriuretic peptide ( NT-proBNP) levels in plasma of patients with stable chronic obstructive pulmonary disease ( COPD) at exertion. Methods Pulmonary function testing, increamental and constant cycle ergometer exercise testing were performed in 19 patients with stable COPD and 10 healthy subjects. Arterial blood gas analysis were measured at rest and maximal exertion in incremental testing. Venous blood samples were drawn both at rest and maximal exercise in constant-load exercise testing and NT-proBNP levels were measured. Results NT-proBNP levels did not change significantly during exercise in the patients with stable COPD[ ( 4803. 86 ±1027. 07 ) ng/L vs ( 4572. 39 ±1243. 33 ) ng /L, P = 0. 542 ] and the control group [ ( 4303. 18 ±771. 74) ng/L vs ( 4475. 71 ±1025. 50) ng /L, P = 0. 676] . NT-proBNP levels were not correlated with parameters of cardiopulmonary exercise testing. Conclusion The factors other than cardiac function may contribute to the exercise intolerance in stable COPD patients without heart failure.
Objective To investigate the effect of inhaled anticholinergics on heart rate recovery (HRR) in patients with stable chronic obstructive pulmonary disease (COPD). Methods Sixty clinically stable patients with stage Ⅱ-Ⅳ COPD according to the Global Initiative for Chronic Obstructive Lung Disease guidelines were recruited. HRR was analyzed in this study between 28 patients who had received tiotropium≥1 year and 32 patients who never used anticholinergics as control, so as to reflect parasympathetic reactivity of the heart. Results HRR was significantly lower in the subjects with tiotropium than that in the controls [(16±6) beats/min vs. (22±8) beats/min, P<0.05]. Multivariate regression analysis revealed that anticholinergics medication could be used as an independent predictor of HRR in the COPD patients. Conclusion Anticholinergics can affect cardiac autonomic function of stable COPD patients.
Objective To determine if the levels of high-sensitivity C-reactive protein ( hs-CRP)and fibrinogen ( Fbg) can predict the risk of acute exacerbation of chronic obstructive pulmonary disease ( COPD) . Methods hs-CRP was measured by latex-enhanced immunoturbidimetric assay and Fbg was assessed by Von Clauss method. The number of exacerbations was recorded during a 6-month follow-up period. Results Fifty patients with stable COPD were enrolled in the study, of whom48 patients completed the trial and two patients dropped out. During the follow-up, 16 patients had once or more acute exacerbations while other 32 patients had no acute exacerbation. The patients were stratified into two groups ( A-exacerbation, B-no exacerbation) . At the baseline, the patients of the group A had lower FEV1 than thegroup B [ ( 1. 1 ±0. 4) L vs. ( 1. 4 ±0. 5) L, P lt;0. 05] . And the group A had higher hs-CRP and Fbg than the group B [ hs-CRP: ( 4. 6 ±3. 3) mg/L vs. 4. 3 mg/L( IQR 5. 5 mg/L) , P lt;0. 05] ; Fbg: ( 3. 8 ±0. 7) g/L vs. ( 3. 1 ±0. 5) g/L, P lt;0. 05] . Nine of 16 patients with a higher level of hs-CRP( hs-CRP gt;3 mg/L) had acute exacerbations. Seven of other 32 patients with normal hs-CRP level had acute exacerbations. The difference in the acute exacerbations rate between the two groups was significant ( 56. 25% vs. 21. 88% , P lt;0. 05) . All four patients with a higher level of Fbg( Fbg gt;4 g/L) had acute exacerbations. Twelve of 44 patients with normal Fbg level ( Fbg≤4 g/L) had acute exacerbations. The patients with Fbg more than 4 g/L had a higher rate of acute exacerbations( 100% vs. 27. 27%, P lt;0. 05) . After adjusting by age, bodymass index ( BMI) , FEV1 , tobacco consumption and other chronic diseases, the risk of acute exacerbation in individuals with baseline hs-CRP gt;3 mg/L was 9. 33 times higher than those with baseline hs-CRP≤3 mg/L ( 95% CI 1. 870-46. 573) . Conclusion Higher level of hs-CRP is associated with the high risk of exacerbation in patients with COPD.
Objective To evaluate if the difference between slow vital capacity ( VC) and forced vital capacity ( FVC) could be used to predict severity of airflow limitation in patients with stable chronic obstructive pulmonary disease ( COPD) . Methods VC and FVC were measured in 200 patients with COPD [ 159 males;mean FEV1 , ( 49.31 ±15.75) % of predicted] and 114 healthy controls [ 64 males; mean FEV1 , ( 99.67 ±13.62) % of predicted] . Results The difference between VC and FVC ( VC - FVC) , which showed a negative correlation with FEV1 of predicted ( r=- 0.412, Plt;0.001) , was significantly larger in the COPD patients than that in the controls [ ( 145.40 ±157.50) mL vs. ( 21. 10 ±61. 30) mL, Plt; 0. 001] . The FVC/VC ratio was significantly lower in the COPD patients than that in the controls [ ( 93. 61 ± 7. 10) % vs. ( 99.27 ±2.24) % , P lt; 0.001] , and was positively correlated with FEV1 of predicted in the COPD patients ( r =0.517, P lt;0.001) . There was significant difference in VC - FVC in the COPD patients with FEV1≥50% of predicted ( 5 patients in GOLD level 1 and 74 patients in GOLD level 2) and those patients with FEV1 lt;50% of predicted ( 106 patients in GOLD level 3 and 15 patients in GOLD level 4) [ ( 78.23 ±108.26) mL vs. ( 189.26 ±169.21) mL, P =0.003] . Conclusion The difference between VC and FVC and the FVC/VC ratio, which are more easily obtained from spirometric test, are able to detect severity of airflow limitation in patients with stable COPD.