**3. The role of interventional EUS in acute cholecystitis**

Medical treatment, such as analgesic as well as antibacterial agents, as well as elective or emergency cholecystectomy are still the main recommendation in daily clinical practice with regards to the severity of AC condition. Laparoscopy recently has become the cornerstone in abdominal surgery because of shorter hospital stay, faster wound healing and less pain at surgical incision site. In the severe case, especially two major factors are identified, such as older age (elderly patients) and comorbidity (cardio-pulmonary problems, uncontrolled diabetes mellitus, advance liver and kidney diseases, and critically ill condition), surgical approach might not be performed in the real clinical practice. On the other hand, percutaneous approach (percutaneous transhepatic gallbladder drainage/PTGBD) has become an alternative in such of situations. It is a very easy procedure and can be performed

bedside, however, uncooperative patients, altered mental status, risk of infection and catheter dislodgement have raised major concerns [20]. Another method can be performed by ERCP technique by placing nasobiliary tube (NBT) or double pigtail plastic stent into the GB through cystic duct cannulation. Major limitations are normal common bile duct (CBD) cannulation and guide wire insertion to the cystic duct which sometimes is not easy to be performed, especially when there is an obstructed cystic duct [21].

EUS has been used widely for managing biliary disorders, such as EUS-guided biliary drainage (EUS BD) for malignant bile duct obstruction as well as a guide for impacted bile duct stone clearance [22]. In technical review by Rana (2021), the echoendoscope position at duodenal area as the same position where EUS BD is performed, is considered as the best location as it is the nearest location to the GB and cystic duct area. Step by step approach is needed to get the successful result even though sometimes it is not always possible. Stabilizing the scope position is the main key for minimize the complications risk. The next step approach is like EUS BD procedure, puncturing the GB with 19-G FNA needle, bile fluid aspiration, guide wire insertion, then followed by fistula track creation using cautery or non-cautery methods. The most crucial step is the stent delivery and deployed (**Figures 2** and **3**) [23]. A randomized controlled trial between EUS GBD and PTGBD by Jang et al. (2012) showed that both methods have similar technical success rate (97% vs. 97%), and there was not statistically significant in term of complications (p = .492) [24]. A systematic review and meta-analysis by Khan et al. (2016) on efficacy and safety of EUS GBD in AC, showing the technical and clinical success rate for transpapillary route was 83% and 93%, whereas transmural route (EUS GBD) technical and clinical success rate were 93% and 97%. The

#### **Figure 2.**

*Fluoroscopy image showed the lumen apposing metallic stent deployment inside the gallbladder. Endoscopy unit Medistra Hospital, Jakarta.*

#### **Figure 3.**

*Endoscopy image of gallbladder drainage with LAMS through the duodenal site. Endoscopy unit, Medistra Hospital, Jakarta.*

comparison difference was 10% (p < .001) and 4% (p = .01). In Endoscopic versus percutaneous methods, recurrent cholecystitis was found more in percutaneous approach than in endoscopic approach [25]. Another study by Tyberg et al. (2016) also shown similar technical success rate between EUS GBD and PTGBD methods [26]. An international multicenter study on EUS GBD in patients who were at high risk for cholecystectomy, showed that the technical and clinical success rate were 95.3%and 90.8%. However, the unplanned events related to the procedure was found higher in non-AC cases than in AC cases with regards to the operator's procedure experience volume [27]. Another retrospective study showed that EUS GBD and percutaneous approach were similarly effective in achieving gallbladder drainage [28]. Recently, there has been a propensity score analysis retrospective study by Teoh et al. (2020) looking at the comparison between EUS GBD and laparoscopic cholecystectomy (LC) for AC, where the result showed the technical success rate was 100% vs. 100%, whereas clinical success rate was 93.3% vs. 100%. After the propensity score matching was done on several factors which might be different from the inclusions' criteria, and there was evidence that two patients died in the EUS GBD group due to aspiration pneumonia and uncontrolled sepsis, however, these events not related to the procedures itself and not statistically significant when compared to the LC group. This study suggested that EUS GBD can be the first approach for patients who are not willing to undergo the surgical approach as well as an alternative in patients who are not fit for surgery. There is no significant difference in the patients' outcome based on 30-day adverse events, recurrent biliary infections, or the need for reintervention [29]. However, there are some major issues which still need to be counted in real clinical practice before it would be recommended in the real clinical practice guideline, such as the cost, operator's experience, multi-disciplinary team approach availability, risk, and complications [30].
