A Study Evaluating the Diagnostic Yield and Safety of the 19-GaUge vs 22-Gauge EBUS-TBNA Needle in Subjects With Suspected Sarcoidosis (GUESS)

Sarcoidosis is an idiopathic disorder characterized by granulomatous inflammation involving various organ systems. The disease is diagnosed based on a suggestive clinicoradiological picture and the presence of non-caseating granulomas in the involved organ, after excluding known causes of granulomatous inflammation. The lung and mediastinal lymph nodes are the most commonly involved structures in sarcoidosis. Various bronchoscopic techniques such as endobronchial biopsy (EBB), transbronchial biopsy (TBLB) and transbronchial needle aspiration (TBNA) are commonly used for acquiring tissue samples.

In the presence of intrathoracic lymph nodes, TBNA is a useful diagnostic modality, especially when combined with endobronchial and transbronchial biopsies. At most centers, TBNA is now guided using endobronchial ultrasound (EBUS). The technique is minimally invasive and also offers the advantage of a selection of the appropriate node for sampling based on the ultrasonographic characteristics. Several studies have demonstrated the superiority of EBUS-TBNA over conventional TBNA (TBNA performed without real-time guidance).

Several technical aspects of EBUS-TBNA have been studied to optimize the yield including the number of aspirations or passes required per lymph node station, needle gauge (21 vs. 22 gauge), suction pressure, the distance travelled by the needle within the lymph node, the number of needle agitations required during a pass, and others.

The novel 19-G Vizishot FLEX EBUS needle (Olympus) is composed of a more flexible material (nitinol) than the 22-G EBUS needle. This allows it to have a larger inner diameter with the same outer diameter as a 22-G EBUS needle. Recent studies have shown that the 19-G needle is safe and has a comparable yield to smaller bore needles. In case of suspected lymphadenopathy due to malignant disorders, aspiration using smaller gauge needles may yield sufficient material for diagnosis. However, in sarcoidosis, larger nodal tissue obtained with a thicker bore needle, the 19-gauge needle, may potentially increase the identification of granulomas. We hypothesize that the 19-gauge EBUS-TBNA needle will have a higher yield as compared to the conventional 22-gauge EBUS-TBNA needle in intrathoracic lymphadenopathy due to sarcoidosis. In this study, we plan to evaluate the yield and safety of the 19-gauge needle vs. the conventional 22-gauge EBUS-TBNA needle in patients with sarcoidosis.