Variables related to complications after pulmonary cryobiopsy

Introduction: Surgical biopsy is the gold standard technique for the pathological diagnosis of diffuse interstitial lung diseases (ILD). Pulmonary cryobiopsy (PC) emerges as an alternative due to its reduction of surgical complications, maintaining an accurate diagnostic yield. However, complications are reported. It is still unclear if these complications could be related to technical, radiological or clinical features. Material and Methods: Retrospective descriptive study of consecutive patients who have undergone a PC for ILD diagnosis between 2012 and 2017. Mild bleeding was considered if only suction was necessary; moderate bleeding if balloon occlusion and cold serum instillation were required; and severe bleeding if a blocker was maintained and patients remainded intubated, or embolization was required. Severe pneumothorax was considered when thoracic drain was inserted. Technical aspects as well as clinical variables were confronted to type and degree of complications. Results: 117 patients were included, 55% male, average age was 61 y-o and 15% were smokers. Average lung function was FVC 86%, FEV1 85%, FEV1/FVC 80%, DLCO 61%. The main radiological findings were ground glass (41%) followed by reticular pattern (28%). In 32% of the cases fibrosis was present. Complications were described in 11.95%: bleeding (moderate 9.4%, severe 0.85%), pneumothorax (mild 0.85%, severe 0.85%), death 0%. PC could not be performed in 7% due to high traction-resistance. Conclusions: Pulmonary cryobiopsy is a safe technique, with a total complication rate of 11.95%, being severe complications rare (1.7%). In the described series, no association between complications and technical, clinical nor radiological features were found.