Endoscopic ultrasound-guided transesophageal thoracic duct puncture in a Swine model: a survival study.

BACKGROUND AND STUDY AIMS: The study of lymph as a biofluid is lacking because of absence of a safe site and technique for lymph acquisition. Injury to the thoracic duct during surgery is known to cause chylothorax. The aim of this interventional study was to puncture the thoracic duct under endoscopic ultrasound (EUS) guidance and observe for complications in a swine model. SUBJECTS AND METHODS: Three female Yorkshire pigs underwent EUS. The thoracic duct was identified by the previously described technique, punctured, and confirmed with a lymphangiogram. Postoperatively, animals were fed and monitored closely for any complications or signs of abnormal behavior indicating pain and/or disease. The animals were euthanized at 1 week, and necropsy was performed per protocol. Main outcome measurements included complications (chylothorax, mediastinitis, perforation, and hemorrhage) during the post-EUS-guided thoracic duct puncture period. RESULTS: No animals developed any complications during the survival period. The thoracic duct was identified and punctured in all animals. A lymphangiogram was additionally obtained to confirm ductal access. No chylothorax, mediastinitis, hematoma, abscess, or fistula formation was identified in any animal on necropsy. CONCLUSIONS: EUS-guided transesophageal thoracic duct puncture is safe as demonstrated by this survival study.

EUS-guided transesophageal study of the human thoracic duct diameter after instillation of intraduodenal fatty acids (EUS-TEST study).

INTRODUCTION: 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. PATIENTS AND METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Pancreatic cysts: a systematic approach and second look.

BACKGROUND: Pancreatic cysts are relatively rare, but constitute an important disease entity that poses a challenge with clinical, radiological, and pathological differential diagnosis. METHODS: New attention has been drawn to pancreatic cysts given their potential cure rates with resection. However, preoperative distinction between neoplastic and benign lesions needs further study for effective strategies in identification and management. The role and safety of cystic fluid analysis remains to be clarified in this context. RESULTS: The presence of mural nodules is a significant indicator for malignancy; however, size as a reliable predictor remains controversial. Specific criteria are required with particular focus on the histologic subtype of pancreatic lesions. CONCLUSION: We review recent developments in the understanding and management of cystic lesions of the pancreas.

Lymph sampling and lymphangiography via EUS-guided transesophageal thoracic duct puncture in a swine model.

BACKGROUND: The thoracic duct plays an important role in fluid balance, lipid absorption, and transport of immunologically active cells. The thoracic duct is difficult to access but is readily identified by EUS. The present study assessed the feasibility of EUS identification and EUS-guided puncture of the thoracic duct in a swine model. METHODS: Transesophageal EUS-guided thoracic duct puncture was attempted in 3 animals under fluoroscopy. In two animals, the thoracic duct was identified by cutdown in the neck; in the third animal, EUS-guided puncture was performed under fluoroscopy alone. In one animal, the thoracic duct was opacified by injecting contrast medium. In the second animal, thoracic duct was injected with patent blue and contrast medium. OBSERVATIONS: Thoracic duct was identified and punctured successfully in all 3 animals. In the first animal, contrast medium containing lymph was aspirated. In the second animal, lymph containing patent blue was aspirated, and, in the third animal, successful puncture was confirmed by obtaining a lymphangiogram. CONCLUSIONS: This pilot study in an animal model demonstrates that transesophageal EUS-guided puncture of the thoracic duct is feasible and that the technique can be used for lymph sampling and/or lymphangiography.