How to design the optimal self-expandable oesophageal metallic stents: 22 years of experience in 645 patients with malignant strictures

Objectives: To evaluate the clinical efficacy and safety of self-expandable metallic stent (SEMS) placement for malignant oesophageal strictures and their relationship with stent designs. Methods: Seven generations of SEMS were used to treat 645 consecutive patients with oesophageal strictures. Logistic regression models were constructed to identify predictive factors associated with complications. Results: Stent placement was technically successful in 641 of 645 patients (99.4%). The clinical success rate was 95.5%. There were 260 (40.3%) complications after stent placement. Due to complications, 68 stents were removed; 66 of 68 stents (97.1%) were removed successfully. Stainless steel (SS) stents (odds ratio [OR] 4.18; 95% confidence interval [CI] 2.10, 8.32) and radiation therapy (RT) before stent placement (OR 4.23; CI 2.02, 8.83) were significantly associated with severe pain. Flared ends (OR 9.63; CI 3.38, 27.43), stricture length <6 cm (OR 2.01; CI 1.13, 3.60), and a stent diameter <18 mm (OR 3.00; CI 1.32, 6.84) were predictive factors of stent migration. Polyurethane membranes were associated with more frequent tumour ingrowth than polytetrafluoroethylene (PTFE) membranes (P = 0.002). Conclusions: Despite the relatively high complication rate, retrievable self-expandable PTFE-covered nitinol stents equipped with a head and a tail appeared to be an effective treatment for malignant oesophageal strictures. Key Points: • Self-expandable metallic stents are now widely used for palliating unresectable oesophageal strictures • Stents equipped with a head and a tail showed decreased stent migration rate • Stainless steel stents and radiation therapy before stenting can cause severe pain • Polyurethane membranes were associated with more frequent tumour ingrowth than polytetrafluoroethylene membranes • Considering the high complication rate, stent retrievability is important for safety reasons