Impact Of Endoscopic Valve Therapy On Hypercapnia In Patients With Chronic Hypercapnic Failure Based On A Severe Lung Emphysema

Background: COPD is often associated with a severe lung emphysema and hyperinflation. In the course of time patients may develop a chronic hypercapnic failure (CHF). The endoscopic lung volume reduction (ELVR) is an established approach to reduce hyperinflation. Previous analysis showed that there is a significant correlation between residual volume and pCO2. This analysis evaluate the impact of valve therapy on pCO2 in patients with chronic hypercapnic failure. Methods: In a retrospective trial, 138 emphysema patients with CHF (pCO2 ≥ 45 mmHg; ) and treated by valve therapy were enrolled. pCO2 (in mmHg, % and absolute), selected lung function parameters (VC, FEV1, RV) and 6 MWT at baseline, 3 and 6 months after intervention were analyzed (un-/paired, to sided t-test; p <0.05 considered statistically significant, Mc Nemar´s test) Results: A significant decrease of mean pCO2 (pre ELVR mean pCO2: 49.8 mmHg ±4.8) could be found at 3 months (mean pCO2: 46.1 mmHg ±12.1; p<0.001) and 6 months (pCO2: 46.4 mmHg ±18.9; p<0.001) after intervention. Patients with a complete atelectasis had a superior benefit with a change of mean pCO2 of -3.8 mmHg ±5.5 vs. -2.2 mmHg ±5.3 in patients with incomplete atelectasis, compared to baseline pCO2. Furthermore VC, FEV1, RV and the exercise capacity in the 6-MWT improved significantly 3 and 6 months after ELVR (all p<0.001). Conclusion: These findings demonstrate that there is a significant reduction of hypercapnia in patients with CHF after valve therapy. Therefore, emphysema patients with stable hypercapnia should not be excluded from this therapeutic modality. Prospective trials however are warranted.