AT THE AATS ANNUAL MEETING

SEATTLE (FRONTLINE MEDICAL NEWS) – Thoracic duct ligation did not seem to prevent chylothorax in a review of 827 esophagectomy cases at Brigham and Women’s Hospital in Boston.

In fact, chylothorax was most likely in patients who had mass ligation of the duct and its surrounding soft tissue, instead of ligation of simply the duct itself.

The results are surprising because ligation is actually meant to prevent chylothorax, but “it didn’t serve that purpose,” said lead investigator Dr. Yifan Zheng, a clinical research fellow at the hospital.

Results have been mixed in previous studies of ligation, with some finding benefit for preventing chylothorax but others not. With contradictory evidence, some surgeons – including some in the Brigham and Women’s review, which covered 11 years of data – opt for routine ligation, while others don’t, Dr. Zheng said at the annual meeting of the American Association for Thoracic Surgery.

At this point, “if you see the thoracic duct and you have concerns about ductal injury, your best bet is to ligate the duct directly. We observed in our series that there is a significantly higher incidence of chylothorax” with mass ligation, she said.

Of the 827 esophagectomies, 635 were performed without thoracic duct ligation; 33 (5.2%) cases developed postop chylothorax. Among the 56 cases with explicit identification and ligation of the thoracic duct alone, chylothorax developed in four (7.1%). There were 136 esophagectomies with mass ligation; 27 (19.9%) developed chylothorax (P = .0314).

The majority of the ligations were performed during open procedures. Mass ligations were mostly done with surgical sutures, while clips were used for direct ductal ligations. It’s likely that surgeons opted for direct ligation when they could see the duct and mass ligation when they could not.

Esophagectomy patients in the study were largely the same, so it’s unclear why some were ligated but others were not. About 75% in both groups had adenocarcinomas, most of which were in the distal esophagus or gastroesophageal junction. About half of the ligated group had preop chemoradiation, versus about 60% in the nonligated group.

Patients who developed postop chyle leaks were also similar, whether or not they were ligated. Most had adenocarcinomas in the distal esophagus or gastroesophageal junction, and the majority had received neoadjuvant therapy. “It’s unlikely that operative approach influenced the development of chylothorax,” Dr. Zheng said.

Both ligated and nonligated patients responded well to chylothorax management. Of the 64 total cases, 28 were successfully treated by thoracic duct embolization and 20 were successfully treated by operative thoracic duct ligation. In 10 cases, thoracic duct embolization was attempted but unsuccessful and all were successfully treated with operative ligation. Six cases were managed with chest tube drainage and total parenteral nutrition. It is possible that patients were ligated because they appeared during surgery to be at risk for postop chylothorax, which would help explain the findings.

It also is possible, however, that ligation itself – especially mass ligation – increases the risk. “The thoracic duct is a high-pressure system, so [blocking it] could create a pressure buildup and a potential leak,” Dr. Zheng said. That might be especially true with mass ligation, when both the thoracic duct and its tributaries are tied off.

Dr. Zheng said that she had no relevant disclosures.

aotto@frontlinemedcom.com

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