A DISAPPEARING ACT: DEFINITIVE MANAGEMENT OF REFRACTORY VANISHING BRONCHUS INTERMEDIUS SYNDROME

Abstract

TOPIC: Transplantation TYPE: Medical Student/Resident Case Reports INTRODUCTION: Vanishing Bronchus Intermedius Syndrome (VBIS) is a post-transplant pathology where the Bronchus Intermedius (BI) of a transplanted right lung undergoes non-infectious ischemic and necrotic transformation distal to the surgical anastomosis, resulting in airway occlusion. The stenosis can be refractory to dilation and stenting, requiring increasingly stringent interventions. Here we report a patient who required definitive surgical management for VBIS. CASE PRESENTATION: A 64 year old male with IPF post single right lung transplant was evaluated by our interventional pulmonology team for BI stenosis. One month post transplant, the patient developed respiratory symptoms and a drop in PFTs, which on serial bronchoscopy revealed mucous plugging and a stenotic mass obstructing the BI. Biopsy of the stenosis ruled out infection, revealing only necrotic changes with granulation tissue, thus supporting a diagnosis of VBIS. Stenosis was only intermittently relieved by repeated balloon dilation and forceps debulking. Thus, the BI was stented with a RML fenestration.However, extension of the stenosis to adjacent lobar bronchi and around the stent required repeated placement, revision, and removal of multiple bronchial stents. Repeated cryoablation and laser ablation of the stenosis only resulted in intermittent relief, but segments also developed slight malacia. Direct injections of steroids and Mitomycin were trialed to arrest proliferation of the granulation tissue. Due to persistent symptoms, bronchial sleeve resection of the stenosis was performed for definitive management, resulting in resolution of stenosis. His symptoms related to VBIS improved significantly, with FEV1 improved from 1.18 to 1.59 pre / post surgery. DISCUSSION: The development of VBIS necessitates a multidisciplinary approach to prevent and manage. Ischemic injury is believed to initiate VBIS, and risk factors reflect this (eg. intraoperative blood loss, ECMO, prolonged ventilation, high PEEP). Balloon dilation and stenting is trialed first, followed by debulking by forceps, cryoablation, or laser. Silicone stents are preferred due to ease of removal. Fully covered self expanding metal stents are preferred if adjacent bronchi become affected but are susceptible to epithelialization. Steroids and antimitotic agents may be attempted to inhibit the proliferating granulation tissue when debulking fails. When conservative treatments fail, surgical excision is feasible with good physiologic and symptomatic results. To the authors knowledge, only two other cases of successful BI sleeve resection for VBIS have been reported in the literature. CONCLUSIONS: In the post-transplant setting, risk factors should be assessed to prognosticate for development of VBIS. VBIS may not respond to dilation and debulking, and a mixture of procedural interventions may abate restenosis. Definitive management may require bronchial sleeve resection. REFERENCE #1: Alraiyes AH, Inaty H, Machuzak MS. Vanishing Bronchus After Lung Transplantation: The Role of Sequential Airway Dilatations. Ochsner J. 2017 Spring;17(1):71-75. REFERENCE #2: Santacruz JF, Mehta AC. Airway complications and management after lung transplantation: ischemia, dehiscence, and stenosis. Proc Am Thorac Soc. 2009 Jan 15;6(1):79-93. REFERENCE #3: Marulli G, Loy M, Rizzardi G, Calabrese F, Feltracco P, Sartori F, Rea F. Surgical treatment of posttransplant bronchial stenoses: case reports. Transplant Proc. 2007 Jul-Aug;39(6):1973-5. DISCLOSURES: No relevant relationships by Gustavo Cumbo-Nacheli, source=Web Response no disclosure on file for john egan;research relationship with United Therapeutics Please note: 2016- ongoing Added 04/19/2021 by Reda Girgis, source=Web Response, value=Grant/Researchresearch relationship with Pfizer Please note: 2014-2020 Added 04/19/2021 by Reda Girgis, source=Web Response, value=Grant/Research Speaker/Speaker's Bureau relationship with Boehringher Ingelheim Please note: 2016-ongoing Added 04/19/2021 by Reda Girgis, source=Web Response, value=Honoraria Speaker/Speaker's Bureau relationship with Genentech Please note: 2016-ongoing Added 04/19/2021 by Reda Girgis, source=Web Response, value=Honoraria No relevant relationships by Ryan Hadley, source=Web Response No relevant relationships by Edward Murphy, source=Web Response No relevant relationships by Ranuka Sinniah, source=Web Response