EUS-Guided Transesophageal Study of the Human Thoracic Duct Diameter After Instillation of Intraduodenal Fatty Acids (EUS-TEST Study)

Abstract

The accession of the thoracic duct (TD) may be vital for obtaining lymph samples, which may be potentially important for early detection of gastrointestinal cancers. The feasibility and safety of endoscopic ultrasound (EUS)-guided TD puncture were recently demonstrated in a swine model. However, the actual process of lymph aspiration is difficult because of small TD diameter (TDD) as well as sluggish flow. This study was designed to examine the change in TDD following intraduodenal instillation of fatty acids (Intralipid(®); manufactured by Fresenius Kabi [Uppsala, Sweden] for Baxter Healthcare [Deerfield, IL]) in patients undergoing diagnostic EUS. Ten patients undergoing EUS for routine indications were enrolled in this interventional study at a tertiary-care center in the United States. Baseline TDD was first recorded with EUS in the mediastinum, and the endoscope was advanced into the second part of the duodenum, where 20% Intralipid was instilled. Patients then underwent the complete EUS procedure, and TDD was again measured at 30, 45, 60, 75, and 90 minutes. Mean age of the patients was 63 years (range, 46-83 years). The mean (±2 standard deviation) TDD at baseline was 0.17±0.04 cm (range, 0.11-0.23 cm). Values for TDD at 30 minutes (0.22±0.03 cm; P=.11), 60 minutes (0.35±0.08 cm; P=.0007), and 90 minutes (0.27±0.08 cm; P=.04) were all higher than the baseline measurement. Maximum increase in TDD was observed at 60 minutes, after which TD started returning toward baseline. TDD increases after intraduodenal instillation of Intralipid in human subjects. This change was statistically most significant at 60 minutes. These observations may be critical for aspiration of lymph samples for early detection of gastrointestinal cancers in humans.