Endoscopic ultrasound-guided gastroenterostomy: another knock-out for simplification

In the last decade, EUS-guided gastroenterostomy (EUS-GE) has evolved into a first-line approach to managing patients with malignant gastric outlet obstruction (GOO) [1]. During this timeframe we have witnessed a surge in clinical data, evolving from small retrospective series into matched multicenter comparisons, prospective series, and more recently randomized controlled trials (RCTs) [2] [3] [4]. The results of the first RCT to be made available seem to confirm previous findings [3], showing that EUS-GE has overcome the limitations of duodenal stenting whilst achieving a similar safety profile [4]. Although its efficacy has been proven beyond any doubt and maldeployment subtypes have been defined, safety and patient selection have remained inadequately explored to date [5] [6]. This mostly stems from the fact that the procedure had not been standardized, complicating comparisons between approaches.

“Taken together, the retrospective data presented suggest that WEST should be the preferred EUS-GE technique whilst the results of further well-powered RCT’s and further technical developments are awaited.”

In general, three technical approaches to EUS-GE have mainly been used in literature. The first technique (direct technique over a guidewire) uses an EUS-guided fine-needle aspiration needle to instill diluted contrast and/or saline into the target loop, followed by stepwise deployment of a wire-guided lumen-apposing metal stent (LAMS). The second technique (wireless endoscopic simplified technique [WEST]), uses an oroenteric catheter that is advanced transluminally, beyond the stricture, into the target loop. Saline is instilled through the catheter to dilate the target loop, distending the latter for subsequent free-hand LAMS placement under EUS visualization. Lastly, so called “assisted EUS-GE techniques” are also being used, albeit mainly in the East. For example, during EUS-guided double-balloon-occluded gastrojejunostomy bypass [EPASS], a dedicated double balloon catheter is inserted, and both balloons are inflated. After the jejunal segment has been further stabilized by saline instillation, the dilated space in between the two balloons can be safely targeted for LAMS placement.

Regardless of the EUS-GE technique, small-bowel mobility can be aggravated by the presence of ascites, which potentially increases the risk of maldeployment and infectious complications. Malignant ascites is furthermore often reflective of impaired short-term survival and this specific patient population stands to benefit the least from this procedure. It has therefore been recommended that malignant ascites interfering with the LAMS trajectory or tense (grade III) ascites should be viewed as contraindications for EUS-GE [5]. All of these considerations illustrate that adequate target loop stabilization is regarded as the most crucial step during EUS-GE. During WEST, this is achieved by catheter-based saline instillation, leading to small-bowel distension and subsequent gastric wall approximation. For the direct technique, fluid is instilled directly into the target loop, which may dissipate or disappear downstream as time passes during device exchange. This approach will therefore also depend on the guidewire to achieve target loop stabilization and successful intrajejunal access, which may induce a false sense of stability, yet still lead to erroneous placement.

To date, no specific studies have been published where the safety and technical success have been compared between the direct technique and WEST, with the only previously available literature comparing the direct technique to a balloon-assisted approach [7].

Monino and colleagues conducted a multicenter retrospective analysis comparing WEST with what the authors termed a “direct technique over a guidewire” (DTOG) [8]. Other less frequently used variations of these techniques and procedures using smaller caliber (< 20 mm) LAMS were excluded, leading to a more homogeneous population for comparison. The authors included 71 procedures in total, with WEST being used in 41 cases and DTOG in 30. The authors showed higher initial technical success using WEST (95.1 % vs. 73.3 %; P = 0.01), as well as a strikingly lower adverse event (AE) rate (14.6 % vs. 46.7 %; P = 0.007). In the WEST group, two maldeployments (4.9 %) were seen, versus six in the DTOG group (20 %). In addition, for 3/8 cases where DTOG failed, WEST could be used as salvage therapy. Taken together, the retrospective data presented suggest that WEST should be the preferred EUS-GE technique, whilst the results of further well-powered RCTs and further technical developments are awaited.

This study also strikingly illustrates the evolution EUS-GE has undergone in the last few years. Where, in the past, many patients suffering LAMS maldeployment would have been sent to surgery, these technical failures have now been further characterized and more rescue techniques have been developed [6]. Acquaintance with these salvage techniques has been recommended as a prerequisite before embarking on EUS-GE procedures [5] [6].

Although the endoscopy community will undoubtedly welcome the current comparative data, some limitations should be addressed. As the authors also mentioned, the retrospective study design does inherently bring forth a certain degree of bias. However, we not only have to take into account selection bias, but also need to acknowledge the potential learning curve effect of these procedures as a source of confounding. In fact, data from this study show that as experience with both techniques grew, it was associated with a reduction in complication rates (see the authors’ Fig. 2 s). Furthermore, limitations regarding the sample size may lead to some important comparative outcomes that did not reach statistical significance going unappreciated, for example maldeployment and major AE rates.

Given its explosive development over the last few years, it is clear that EUS-GE has become entrenched in the management of malignant GOO, even in the absence of RCTs. Besides standardization of the procedure and terminology, additional technical developments are being pursued to further improve enteric loop stabilization. As Bruce Lee once said: “Simplicity is the key to brilliance.” The same applies to EUS-GE: by standardization and simplification, we can strive toward further reducing complications to the absolute minimum, ultimately aiming for the maldeployment knock-out.

Publication History

Article published online:
18 September 2023

• References

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