Intraoperative ICG testing can determine post-LSG leaks

Intraoperative indocyanine green (ICG) testing may be helpful in determining which patients are at an increased risk of leakage after a laparoscopic sleeve gastrectomy (LSG) and if adjunctive measures are needed intraoperatively, according to researchers from the University of Foggia, Foggia, Italy. However, the investigators stated that further testing is required to determine if ICG will predict leakage due to ischaemia. The findings were featured in the paper, ‘Can indocyanine green during laparoscopic sleeve gastrectomy be considered a new intraoperative modality for leak testing?’, published in BMC Surgery.

Figure: 1a Evaluation of perfusion of the staple line of the stomach by using the indocyanine green test. 1b Intraoperative picture of the staple line of the stomach

The researchers noted that gastric leakage is the most serious complication of sleeve gastrectomy and claimed that the pathogenesis of gastric leakage has still not been clarified, though it is multifactorial (ischaemic, mechanical, inflammatory). Furthermore, despite there being various methods of detecting intraoperative leaks, there is no standardised algorithm for the intraoperative diagnosis of gastric leak is available.

Therefore, the researcher undertook a study to examined if indocyanine green fluorescence (IGF) during LSG could determine how perfusion of the staple line of the stomach can affect the onset of leakage.

Eighty-two consecutive patients underwent LSG with ICG fluorescence angiography (61 female and 21 male patients) from January 2020 to December 2021. The operations were performed by the same surgical team applying the same standardised technique. The mean age was 43.6 years in the male group and 37.6 years in the female group (mean 39.18 years). The mean preoperative BMI was comparable between the two groups (45.16 kg/m2 in the male group vs. 45.06 kg/m2 in the female group). At least one major comorbidity was found in all patients: the most prevalent was hypertension (52 patients, 63.41%), followed by diabetes (15 patients, 18.3%), COPD and/or OSAS (7 patients, 8.5%), and osteoarthritis (8 patients, 9.7%).

The sleeve resection was shaped around a 40-French bougie held in place using a mechanical linear stapler; 5ml of ICG was then injected intravenously to identify gastric vascularisation, carefully assessing the angle of His. Adequate perfusion was defined as “the direct and clear visualization of the fluorescence around the gastric tube, after an estimated time of 150–180 s following i.v. administration” (Figure: 1a, b).

In the event of insufficient perfusion, our anticipated options consisted of suture reinforcement by buttressing (if the gastric tube was large enough at the GE junction and the inadequate perfusion area was confined to the peripheral area) or fibrin glue (if the area of inadequate perfusion was greater than the peripheral area). Intraoperative conversion to Roux-en-Y gastric bypass (RYGBP) was not considered unless perfusion was absent throughout the upper part of the gastric tube (due to the unbearable risk of leakage). A methylene blue test was routinely performed after fluorescence. The procedure concluded with the insertion of an intra-abdominal drain along the suture line.

The procedure was performed in all patients without ICG-related adverse events and the methylene blue test was negative in all patients. Blood supply to the GE junction was rated “satisfactory and adequate” in all patients. Routine swallow tests with Gastrografin on the second postoperative day were negative for leaks in all patients.

However, one patient (1.2%) showed signs and symptoms related to gastric discharge on the fifth postoperative day, and the diagnosis was confirmed by CT with Gastrografin (she was treated with the endoscopic placement of pigtail stents).

The leakage rate of the group evaluated with ICG was compared with that in the period from 2017 to 2019 in all patients undergoing sleeve gastrectomy in our centre; the total number of patients evaluated without ICG tests who had leakages was 2, with a leakage rate of 2.5%.

According to the researchers, ICG fluorescence angiography facilitates evaluation of the blood supply during surgery and is considered an inexpensive and feasible method to establish vascularity in the desired area. In this study, one leakage was recorded in an ICG-tested LSG despite achieving adequate underlying cause of the leak is multifactorial, and leakages are not only due to poor vascularization of the gastric tract.

The group leakage rate was 1.2%, lower to that of the non-tested patients, but to better understand this finding, the number of LSGs with follow-up data must be increased to obtain significant values, they added.

From the initial data, they did not find any segmental areas with ischaemia along the greater curvature, focusing mainly on the area near the angle of His, despite one patient developing gastric leakage on the fifth postoperative day. They did observe a lower leakage rate in the group tested with ICG, but these are preliminary data, and studies with larger numbers of patients are needed.

“Despite the lower leak ratio of patients undergoing the ICG test, the occurrence of gastric fistula could not be ruled out; in fact, all the patients who underwent ICG testing during LSG showed optimal perfusion,” the researchers stated. “These data led us to believe that multiple factors are related to the pathophysiology and incidence of gastric fistula in the context of LSG operations.”

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