Fate of contralateral asymptomatic bullae in patients with primary spontaneous pneumothorax

OBJECTIVES This retrospective cohort study aimed to analyse the impact of asymptomatic blebs/bullae on the occurrence of primary spontaneous pneumothorax (PSP) by monitoring the natural course of contralateral blebs/bullae in patients with ipsilateral pneumothorax. METHODS From January 2003 to December 2017, 1055 patients [age 19.6 ± 3.98 years (mean ± standard deviation), 953 men] experiencing the first episode of unilateral PSP were enrolled in this study, excluding patients aged 30 years or more. The presence, number and maximal size of the blebs/bullae were investigated in contralateral asymptomatic lungs based on high-resolution computed tomography. RESULTS Multiple and single blebs/bullae were noted in contralateral lungs in 425 (40.3%) and 88 (8.3%) patients, respectively. The median follow-up period was 44.0 (interquartile range 71.5) months. The 1-, 3- and 5-year cumulative occurrence rates of PSP in contralateral lungs were 7.9%, 13.7% and 16.7%, respectively. On multivariable analysis, younger age [hazard ratio (HR) 1.19, 95% confidence interval (CI) 1.12–1.27; P < 0.001) and multiple bullae (HR 4.42, 95% CI 3.06–6.38; P < 0.001) were independent risk factors for spontaneous pneumothorax in the contralateral lung. The 5-year cumulative occurrence rates of PSP were significantly higher in patients with multiple blebs/bullae than in those with no or a single bleb/bulla (28.2% vs 8.5%, respectively; P < 0.001). CONCLUSIONS Asymptomatic blebs/bullae often lead to PSP. If the patient is eligible for surgery for pneumothorax, preemptive surgery for contralateral bullae could be considered, especially in patients with multiple blebs/bullae.