Pneumothorax after Bronchoscopic Lung Volume Reduction with Endobronchial Valves(EBV-BLVR): Is there any correlation with number of valves?

Purpose: EBV-BLVR has evolved as a minimally invasive therapy for advanced emphysema. Optimal patient selection improves results, but also the likelihood of pneumothorax (pnx). There is, however, little evidence of what its rate could be influenced by. We hypothesized an association with the number of valves used. Aim: to investigate a correlation between the rate of pnx and the number of valves used. Methods: we performed a retrospective evaluation of pnx rate in correlation with number of valves andtreatedlobein all EBV-BLVR procedures from 2015 to 2017 in two referral centers. Results: Overall pnx rate in 99 patientswas 24%. Pnx occurred in 25% within 2 hours after treatment, 37.5% within 6, 45.8% within 12, 70.8% within 24 and 79.1% within 48 hours. The incidence of pnx was 31% LUL, 20% LLL, 35.7% RUL, 9.5 % RLL. No significant difference in pnx rate was found comparing right and left lung (p= 0.51) or leftupper and lower lobe; we found a trend (p=0.057) to a lower incidence of pnx when RLL was excluded compared to RUL. In patients treated with 1 EBV the rate of pnx was 18.2%, 28.9 % with 2 valves and 32.1%with 3 valves. No pnx were observed in patients treated with 5 or 6 valves. The number of valves Conclusion: Our findings confirm no correlation between pnx rate and the treated lung. Pnx is less common in RLL. Interestingly using more than 3 valves might reduce the incidence of pnx. There’s poor knowledge on other possible factors influencing pnx rate. Prospective studies might correlate quantitative features of CT (lobar volume and density)withthe likelihood of pnx.