Self-expanding metal esophageal stent with anti-reflux mechanism

Background: When deployed across the gastroesophageal junction, self-expand ing metal esophageal stents can predispose to gastroesophageal reflux. Our aim was to evaluate the efficacy of a self-expanding metal esophageal stent that was modified to prevent gastroesophageal reflux. Methods: The polyurethane coating of a metal Z-stent was extended beyond it s lower end to form windsock-type valve. The anti-reflux property of this s tent was studied in vitro by submerging the stent under water and measuring the pressure required to invert the valve. Esophageal acid exposure time w as measured in 5 dogs with a standard and the modified stent placed across the gastroesophageal junction. The modified stent was also placed in 11 pat ients with cancer of the gastroesophageal junction who were prospectively f ollowed. Results: The pressure required to invert the valve was directly proportiona l to the thickness of the valve membrane (48 +/- 0.4 cm water for a 0.0067- inch thick membrane). Esophageal acid exposure time was significantly less with the modified stent as compared with a standard stent (1% +/- 0.3%, 49% +/- 11%, respectively, p = 0.03). Dysphagia score in patients improved fro m 3.4 +/- 0.1 to 1.1 +/- 0.2 (p < 0.001). Daytime heartburn and regurgitati on scores were less than 1 (score 10 = severe). No patient complained of no cturnal reflux symptoms. Karnofsky performance status scale did not improve significantly. Conclusions: The efficacy of the modified stent in relieving dysphagia is c omparable with a standard stent. It also effectively prevents gastroesophag eal reflux.