PRECLINICAL EVALUATION OF THIN CONVEX PROBE ENDOBRONCHIAL ULTRASOUND-GUIDED TRANSBRONCHIAL NEEDLE ASPIRATION FOR INTRAPULMONARY LESIONS

Abstract

TOPIC: Procedures TYPE: Original Investigations PURPOSE: A prototype thin convex probe endobronchial ultrasound scope (TCP-EBUS; distal outer diameter [OD] 5.9 mm; Olympus Medical Systems Corp., Japan) was developed to enable access to distal airways and diagnose intrapulmonary lesions. The objective of this study was to evaluate the potential clinical utility of TCP-EBUS by preclinically assessing its bronchial accessibility, the feasibility of EBUS-guided transbronchial needle aspiration (EBUS-TBNA) of intrapulmonary targets, as well as its short- and medium-term safety. METHODS: For bronchial accessibility, the TCP-EBUS was inserted into the distal airways of ex-vivo human lungs (n=5). TCP-EBUS was compared with several clinically-available bronchoscopes (BF-H190 bronchoscope, OD 5.5 mm; BF-Q190 bronchoscope, OD 4.8 mm; BF-Y0063 CP-EBUS scope, OD 6.6 mm, Olympus Medical Systems Corp., Japan). The maximum reach, in terms of bronchial generation, for each scope was documented using fluoroscopy and bronchoscopy. To quantify the minimum diameter of the distal airway accessed by the TCP-EBUS, an agarose-barium sulfate mixture was injected transbronchially to mark the bronchus where the TCP-EBUS could reach, followed by cone-beam CT to measure the diameter radiographically (n=3). For intrapulmonary lesion EBUS-TBNA feasibility, an agarose-barium mixture was injected transbronchially into the lungs in a live pig to create pseudo-tumor targets; successful EBUS-TBNA was based on retrieval of dyed agarose material. The short- (≤1 hr) and medium-term (≤10 d) safety of TCP-EBUS insertion and EBUS-TBNA in the periphery were observed physiologically and radiologically (fluoroscopy, computed tomography [CT]) in live pigs (n=5). RESULTS: For bronchial accessibility, TCP-EBUS demonstrated greater reach than the standard CP-EBUS in all bronchi, as well as surpassed the 5.5 mm-bronchoscope in 62.7% (131/209) and the 4.8 mm-bronchoscope in 27.2% (57/209) of assessed bronchi. The median bronchial generation and the mean diameter of bronchi TCP-EBUS reached was 4 (range 3-7) and 3.3±0.7 mm, respectively. No difficulties with EBUS-TBNA of intrapulmonary pseudo-tumors were observed. No major complications related to TCP-EBUS-TBNA in distal airways were observed in the five pigs. Scattered mucosal erythema of the bronchial walls was observed immediately after TCP-EBUS insertion in all pigs; this self-resolved by day 10. One pig developed an inflammatory scar in the right upper lobe by day 10. CONCLUSIONS: TCP-EBUS insertion appears to be safe and improves access to the distal airways. It has the potential to facilitate EBUS-TBNA of intrapulmonary lesions in the central and middle lung fields. CLINICAL IMPLICATIONS: Ultrasound-guided real-time sampling for intrapulmonary lesions located in the inner two-thirds lung fields may be safely conducted with the TCP-EBUS bronchoscope. DISCLOSURES: No relevant relationships by Masato Aragaki, source=Web Response No relevant relationships by Nicholas Bernards, source=Web Response No relevant relationships by Harley Chan, source=Web Response No relevant relationships by Zhenchian Chen, source=Admin input No relevant relationships by Andrew Effat, source=Web Response No relevant relationships by Alexander Gregor, source=Web Response No relevant relationships by Terunaga Inage, source=Web Response No relevant relationships by TSUKASA ISHIWATA, source=Web Response No relevant relationships by Tomonari Kinoshita, source=Web Response No relevant relationships by Yamato Motooka, source=Web Response no disclosure on file for Koichiro Tatsumi; No relevant relationships by Hideki Ujiie, source=Web Responseresearch support relationship with Olympus Corporation Please note: $5001 - $20000 by Kazuhiro Yasufuku, source=Web Response, value=Grant/Research Consultant relationship with Olympus America Inc Please note: $1001 - $5000 by Kazuhiro Yasufuku, source=Web Response, value=Consulting fee Consultant relationship with Medtronic Please note: $1001 - $5000 by Kazuhiro Yasufuku, source=Web Response, value=Consulting fee Consultant relationship with Johnson and Johnson Please note: $1001 - $5000 by Kazuhiro Yasufuku, source=Web Response, value=Consulting fee Consultant relationship with Auris Surgical Robotics Please note: $1001 - $5000 by Kazuhiro Yasufuku, source=Web Response, value=Consulting fee