Covered versus uncovered metal stents for malignant gastric outlet obstruction: a systematic review and meta-analysis.

Abstract Background and Aims Self-expandable metal stents are used for palliation of malignant gastric outlet obstruction (GOO). Studies comparing covered self-expandable metallic stents (C-SEMSs) and uncovered self-expandable metallic stents (U-SEMSs) have led to inconclusive results. We compared efficacy and safety of C-SEMSs versus U-SEMSs in patients with GOO. Methods MEDLINE, EMBASE, Cochrane Library, from 2000 to 2019 aimed at identifying available studies comparing C-SEMSs versus U-SEMSs in patients with GOO. Primary outcomes were stent survival and patient survival, whereas secondary outcomes were clinical and technical success, GOOSS score after the procedure, overall adverse events, reintervention rate, dysfunction rate, stent occlusion, and stent migration. Results Overall, 7 randomized controlled trials (RCTs) and 9 observational studies were identified, including 1741 patients. C-SEMSs were associated with higher stent survival (HR, 0.68; 95% CI, 0.48-0.96) whereas patient survival did not statistically significantly differ between C-SEMS and U-SEMS groups (HR, 0.96; 95% CI, 0.75-1.23). Clinical and technical success were not statistically different between groups (OR, 1.1; 95% CI, 0.76-1.61 and OR, 0.69; 95% CI, 0.21-2.3). There were no differences in terms of overall adverse events, reintervention rate, dysfunction rate, and GOOSS rate ≥2 after SEMS placement. U-SEMSs were associated with higher rate of occlusion (OR, 0.34; 95% CI, 0.21-0.53), whereas C-SEMSs with higher rate of migration (OR, 4.28; 95% CI, 2.79-6.57). Conclusions C-SEMSs were associated with higher stent survival, compared with U-SEMSs, whereas no differences in terms of patient survival emerged. However, U-SEMSs were associated with higher risk of occlusion and C-SEMSs with migration. Further studies using new C-SEMSs with antimigration system are needed.