Pulmonary vein thrombosis following bronchoscopic cryobiopsy: A case report

Abstract Pulmonary vein thrombosis (PVT) is a rare and often underdiagnosed condition typically associated with thoracic surgery, catheter ablation, malignancy, or infectious etiologies. Symptoms are frequently nonspecific, such as cough, dyspnea, chest pain and hemoptysis; resulting from pulmonary congestion. We report a unique case of PVT occurring shortly after a bronchoscopic cryobiopsy, suggesting this procedure as a potential, albeit rare, precipitating factor. Case Presentation: A 54-year-old Caucasian man with a history of morbid obesity, hypertension, obstructive sleep apnea, diabetes, and remote atrial fibrillation managed with radiofrequency ablation (RFA) in 2010 presented with mild exertional dyspnea. He had been off anticoagulation since the ablation. Chest CT revealed interstitial changes in the left lower lobe and mild mediastinal lymphadenopathy. ACE levels were normal, and IgG4 levels were elevated. He underwent diagnostic bronchoscopy with endobronchial ultrasound (EBUS) and left lower lobe bronchoscopic cryobiopsy. Pathology demonstrated ectatic large airways with scarring and bronchiolar metaplasia. While a few giant cells were noted, there was no histologic evidence of sarcoidosis, lymphoma, or IgG4-related disease. Five days post-procedure, he developed new-onset cough, worsening dyspnea, and mild hemoptysis. CT pulmonary angiography ruled out pulmonary embolism but revealed left pulmonary vein thrombosis extending into the left atrium and infiltrative changes in the left lung base. There was no previous personal or family history of venous thrombosis. He was started on cautious low-dose heparin infusion, later escalated to full-dose anticoagulation. His hemoptysis gradually resolved, and he was discharged on Apixaban. An eight-week follow-up CT angiogram showed partial improvement but persistent pulmonary vein and left atrial thrombus. A mediastinal lymph node measuring 2.4 cm also remained. After three months of systemic anticoagulation, he underwent robotic-assisted video-assisted thoracoscopic surgery (VATS) with wedge resection and mediastinal lymph node biopsy. Pathology: Lung biopsy demonstrated hemosiderin-laden macrophages, intimal fibroplasia of pulmonary veins and venules, and patchy parenchymal organization without malignancy. Mediastinal lymph nodes had preserved architecture and polyclonal plasma cell aggregates. There was no histologic evidence of lymphoma or sarcoidosis. The findings were consistent with pulmonary hemorrhage due to venous hypertension from pulmonary vein thrombosis. Discussion: While pulmonary vein thrombosis has been previously reported following atrial ablation procedures, this patient's RFA occurred 15 years prior, making it an unlikely sole cause. The temporal relationship between symptom onset and bronchoscopic cryobiopsy, along with characteristic pathology and imaging, supports the hypothesis that the procedure may have directly or indirectly contributed to the development of thrombosis. Conclusion: Pulmonary vein thrombosis is a rare but serious complication that may occur following bronchoscopic cryobiopsy. This case highlights the importance of recognizing this potential adverse outcome, especially in patients presenting with unexplained respiratory symptoms post-procedure. Early detection and anticoagulation are critical to managing this condition and preventing systemic embolization.