To date, many studies have shown promising outcomes in patients with transmural defects of the UGI tract with EVT as a definitive treatment. However, those previous studies included only a limited number of patients. Recently, several systematic reviews were reported on the usefulness of EVT in transmural defects of the UGI tract.[17, 46–48] However, those previous reviews were only descriptive and did not show any statistical analysis with a summary estimate. Therefore, a meta-analysis was needed to synthesise the available data on the efficacy of EVT in transmural defects of the UGI tract. Our meta-analysis contained case series in which a single group was assessed with no within-study comparisons. Nevertheless, this meta-analysis has an advantage over a narrative review because it assessed effect sizes and integrated all of them in a single statistical analysis.
In this meta-analysis, the closure rate of EVT for transmural UGI defects was rather excellent (85%), with low mortality (11%), complication (10%), and post-EVT stricture (14%) rates. And, no significant difference was found in successful closure (OR: 1.45, 95% CI: 0.45–4.67), mortality (OR: 0.77, 95% CI: 0.24–2.46), complications (OR: 0.94, 95% CI: 0.17–5.15, p = 0.94), and post-EVT stricture (OR: 0.70, 95% CI: 0.12–4.24, p = 0.70) according to the aetiology of the transmural defect (perforation vs. leak and fistula). Although the aetiology of transmural UGI defects was different, the efficacy of EVT was similar between the groups. In addition, the successful closure rate was significantly higher with EVT than with SEMS (OR: 3.52, 95% CI: 1.79–6.91). To date, only one meta-analysis has reported studies comparing EVT and SEMS for the treatment of oesophageal defects. In this previous study, the closure rate of oesophageal leak was also significantly higher with EVT than with SEMS, similar to our results. However, the number of included patients was smaller than that in our meta-analysis.
The principle of EVT is similar to the classical vacuum-assisted closure treatment, which is a well-established therapy for chronic superficial wounds. In EVT, a polyurethane sponge is placed into the defect to treat it with the application of negative pressure. Defect healing is achieved through the continuous drainage of dirty fluid, thus decreasing bacterial colonisation, enhancing vascularity, and promoting tissue granulation.[50, 51] An internal vacuum sponge (endo-SPONGE) device was first successfully introduced for UGI anastomosis leak in 2008. Since then, EVT has been used for the management of UGI defects and has shown good short-term and long-term clinical outcomes. Meanwhile, SEMS placement has also shown effective results for UGI defects.[5, 6] However, stent therapy may be accompanied by additional abscess drainage, local pressure necrosis of the mucosa, stent migration, stent ingrowth, bleeding, and perforation. Surgery is also one of the strategies for transmural defects of the UGI; however, it has been known to be associated with a high mortality rate.[3, 4] To date, comparative studies between different treatment modalities for UGI defects are rare. Therefore, the clinical evidence on EVT for UGI defects is still insufficient for directing treatment modalities. According to our meta-analysis, EVT is an effective and safe treatment method for treating leaks and fistulae as well as perforations. In addition, EVT seems to have a significantly higher success rate in healing UGI defects than SEMS placement.
Usually, transmural defects of the UGI tract are classified as perforations, leaks, or fistulae. Of these, fistulae have been known to be the most difficult to close because the epithelial tract is often fibrotic and they arise in unhealthy tissue, which is inflamed, damaged, or ischaemic. Although the included cases were too few (n = 6), this meta-analysis showed a successful closure rate of 50% in patients with fistula. Given the poor response to other treatments such as SEMS placement, EVT would be promising option for treating patients with fistula.
The major disadvantages of EVT are the necessity for repetitive endoscopic procedures, nasogastric tube-related discomfort, and sponge dislocation. The main and most dreadful event associated with EVT is massive bleeding.[17, 46] It can occur from a fistula between the cavity and the main vessels and from rupture of a pseudoaneurysm from circumjacent vessels or heart chambers. More frequent changes of the sponge may be helpful to prevent or reduce the risk of severe bleeding. Moreover, massive bleeding can occur in cases of intracavitary therapy in which direct contact to blood vessels is possible. Therefore, intraluminary EVT may be safer than intracavitary EVT. Additionally, computed tomography scans should be reviewed before starting intracavitary EVT to exclude vascular issues. In our review, post-EVT stricture occurred in 14% cases. However, all strictures were easily resolved through endoscopic dilatations (26 cases).