Comparison of 1.1-mm and 1.7-mm Probes in Transbronchial Mediastinal Cryobiopsy: A Randomized Trial

Recent studies have shown that combined use of endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) and cryobiopsy provides a higher diagnostic yield for mediastinal lesions as compared with EBUS-TBNA alone. Currently, cryoprobes with diameters of 1.1mm and 1.7mm have been reported to be used for mediastinal cryobiopsy.

We conducted a randomized controlled trial to evaluate and compare the diagnostic safety and efficacy profile the two cryoprobes in mediastinal disease. Consecutive patients with mediastinal lesions (≥1cm in the short axis) were prospectively enrolled. After four passes of needle aspiration, participants underwent mediastinal cryobiopsy with 1.1-mm and 1.7-mm cryoprobes in a randomized order. The main endpoints included procedural success rate, diagnostic yield, and safety.

A total of 137 patients were recruited and randomized. Both 1.1-mm and 1.7-mm probe cryobiopsies added diagnostic value to EBUS-TBNA. (94.2% vs 75.9%; p<0.001; 92.0% vs 75.9%; p<0.001; respectively). Supplementing EBUS-TBNA with either 1.1-mm or 1.7-mm probe-cryobiopsy resulted in no differences in overall diagnostic yield (94.2% vs 92.0%; p=0.48). Nevertheless, direct comparison revealed a significantly improved overall diagnostic yield with 1.1-mm cryoprobe relative to 1.7-mm cryoprobe, primarily due to technical failures associated with the latter (88.3% vs 79.6%; p=0.048). Additionally, 1.1-mm and 1.7-mm cryoprobes yielded mediastinal specimens of similar size. Both approaches were safe, with no serious adverse events reported.

1.1-mm cryoprobe demonstrates better performance in transbronchial mediastinal cryobiopsy vs 1.7-mm cryoprobe, making it a viable adjunct to traditional needle biopsy.