Читать книгу Clinical Pancreatology for Practising Gastroenterologists and Surgeons - Группа авторов - Страница 192

Since their advent just a few years ago, LAMS have fundamentally altered the endoscopic management approach to both solid and cystic collections. These stents allow continued access with decreased risk of migration, can be easily and safely placed endoscopically, and enable drainage of larger amounts and sizes of tissue and allow direct endoscopic access into the collection for debridement. The endoscopic access options available to the endoscopist include placement of plastic stents or LAMS. Adler et al. [34] in a multicenter (four tertiary care centers across the United States) retrospective study of 80 patients with pancreatic fluid collections drained with LAMS showed that the overall technical success rate was 98.7% with no statistically significant difference in the technical success rate between the inpatient and outpatient groups, although there was a significantly lower number of procedures required for resolution in the inpatient group compared to the outpatient group (2.3 vs. 3.1; P = 0.025), as well as significantly lower adverse event rates in the inpatient versus the outpatient group (P <0.01). While critically ill patients require inpatient hospitalization and management, this study demonstrates that those who have symptomatic collections who are otherwise stable may be able to be managed as outpatients in an ambulatory setting with close interval follow‐up.

There have been multiple studies examining the use of LAMS or fully covered metal stents versus plastic stents in the management of WON. Abu Dayyeh et al. [35] performed a retrospective study of 94 patients with WON at the Mayo Clinic in which 36 patients underwent double‐pigtail plastic stent placement and 58 patients underwent large‐caliber fully covered self‐expanding metal stent placement. There was no significant difference in the resolution rates between the two groups, and interestingly of the 80% of patients successfully treated with endoscopic approaches alone without the need for percutaneous intervention, nearly half (49%) only required transmural drainage without subsequent necrosectomy. WON was significantly more likely to resolve without the need for endoscopic necrosectomy in the self‐expandable metal stent group compared with the double‐pigtail plastic stent group (60.4% vs. 30.8%; P = 0.01), which remained more likely after adjustment for patient age, size, and location of the necroma (OR 4.5, 95% CI 1.5–15.5). There was a clinically significant higher risk of bleeding requiring endoscopic intervention in the plastic stent group compared to the metal stent group (14% vs. 2%; P = 0.02). The results of LAMS in drainage remain somewhat mixed. Bang et al. [36] recently randomized 60 patients with WON to LAMS (n = 31) or plastic stent (n = 29) placement in which there was no significant difference in the total number of procedures performed (LAMS: median 2, range 2–7 vs. plastic: median 3, range 2–7). Unsurprisingly, procedure duration was significantly shorter using LAMS (15 vs. 40 minutes; P <0.001); however, there were significantly higher stent‐related adverse event rates with LAMS (32.3% vs. 6.9%; P = 0.01) and higher cost with LAMS (US$12 155 vs. US$6609; P <0.001).

Importantly, one of the key factors in minimizing stent‐related adverse events was performance of follow‐up imaging and stent removal at three weeks post placement if the WON had resolved. This is especially important for preventing complications from collapse of the collection, with erosion of the posterior wall of the collection against the stent causing bleeding, which can be prevented by close interval imaging with removal of the stent on near collapse of the collection. Mohan et al. [37] performed a systematic review and meta‐analysis examining LAMS and plastic stents in WON in which nine studies of 737 patients with LAMS were compared to six studies of 527 patients with plastic stents. The pooled clinical success rate showed no significant difference between LAMS (88.5%, 95% CI 82.5–92.6) and plastic stents (88.1%, 95% CI 80.5–93.0; P = 0.93). Further, there was no significant difference in the pooled rates of all adverse events (LAMS 11.2%, 95% CI 6.8–17.9 vs. plastic stents 15.9%, 95% CI 8.4–27.8; P = 0.38). The authors concluded that there were equal clinical outcomes and adverse events among both stent types, though significant heterogeneity was present in all included studies and end points.

Concurrently, in a multicenter, international, retrospective study of 189 patients at 14 centers with WON comparing LAMS and plastic stents, there was a significantly higher clinical success rate with use of LAMS (80.4% vs. 57.5%; P = 0.001) with similar rates of need for percutaneous drainage and a greater need for surgery in the plastic stent group. Of note, the rate of WON recurrence following initial clinical success was significantly greater in the plastic stent group compared to LAMS (22.9% vs. 5.6%; p = 0.04), with the conclusion that LAMS was associated with higher clinical success, short procedural time, decreased need for surgery, and decreased overall rate of recurrence [38]. Interestingly, in a cost‐effectiveness analysis comparing LAMS with plastic stents for WON, LAMS were found to be more effective than plastic stents (92% vs. 84%), though LAMS were markedly more expensive ($US20 029 vs. $US15 941). This cost‐effectiveness modeling favored LAMS, with an incremental cost‐effectiveness ratio of $US49 214 in order to perform one additional successful drainage using LAMS compared to plastic stents, which was confirmed on sensitivity analyses [39].

Lastly, once endoscopic access into the collection has been obtained, there are multiple tools at the endoscopist’s disposal to enable endoscopic debridement and necrosectomy. Some of the most common tools include use of rat‐tooth forceps, snare, and Roth nets to remove pieces of debris. Biliary extraction baskets are also frequently used to this end point. There remains significant opportunities for innovation in this field as currently available tools are adapted to fit new indications and situations.