Double-layered covered stent for the treatment of malignant oesophageal obstructions: Systematic review and meta-analysis

AIM To investigate the efficacy of double-layered covered stent in the treatment of malignant oesophageal obstructions. METHODS A systematic review and meta-analysis was performed following the PRISMA process. PubMed (Medline), EMBASE (Excerpta Medical Database), AMED (Allied and Complementary medicine Database), Scopus and online content, were searched for studies reporting on the NiTi-S polyurethane-covered double oesophageal stent for the treatment of malignant dysphagia. Weighted pooled outcomes were synthesized with a random effects model to account for clinical heterogeneity. All studies reporting the outcome of palliative management of dysphagia due to histologically confirmed malignant oesophageal obstruction using double-layered covered nitinol stent were included. The level of statistical significance was set at α = 0.05. RESULTS Six clinical studies comprising 250 patients in total were identified. Pooled technical success of stent insertion was 97.2% (95%CI: 94.8%-98.9%; I2 = 5.8%). Pooled complication rate was 27.6% (95%CI: 20.7%-35.2%; I2 = 41.9%). Weighted improvement of dysphagia on a scale of 0-5 scoring system was -2.00 [95%CI: -2.29%-(-1.72%); I2 = 87%]. Distal stent migration was documented in 10 out of the 250 cases examined. Pooled stent migration rate was 4.7% (95%CI: 2.5%-7.7%; I2 = 0%). Finally, tumour overgrowth was reported in 34 out of the 250 cases with pooled rate of tumour overgrowth of 11.2% (95%CI: 3.7%-22.1%; I2 = 82.2%). No funnel plot asymmetry to suggest publication bias (bias = 0.39, P = 0.78). In the sensitivity analysis all results were largely similar between the fixed and random effects models. CONCLUSION The double-layered nitinol stent provides immediate relief of malignant dysphagia with low rates of stent migration and tumour overgrowth