Safety and efficacy of large-diameter esophageal metal stents

We read with great interest the recent paper by Hasan et al. [1], reporting three cases of development of esophagorespiratory fistulas at the proximal edge of the superior flange of a large-diameter Flamingo Wallstent. In all three cases the fistula developed several months after stent insertion and there was no evidence of any malignancy at the site of the fistula. The authors speculated that the fistulas had formed as a result of pressure necrosis caused by the proximal flange, and recommended that these large-diameter Flamingo stents should not be used in patients with a life expectancy of more than 6 months. Moreover, in a letter to the editor, Siersema et al. [2] emphasized the results of a prospective study of 40 patients: in this study, the large-diameter Flamingo Wallstent appeared to be associated with an increased risk of esophageal complications, particularly bleeding, compared with the small-diameter one [3]. Even though the difference was not statistically significant, the authors recommended that the large-diameter stents should not be used until studies have provided more data on the effect of the stent diameter on efficacy and on the risk of complications.

We were intrigued by these reports concerning the safety and efficacy of large-diameter esophageal metal stents. In our institution, since August 1997, we have introduced a total of 128 Ultraflex stents (Boston Scientific, La Garenne Colombes, France), 89 of which were of large-diameter (28/22mm). In contrast to the abovementioned findings, in our experience, use of the large-diameter stents was associated with a reduced rate of early complications and a significantly lower rate of late complications in comparison with the small-diameter Ultraflex stents (23/17 mm), irrespective of tumor location [4]. No significant bleeding occurred, and we documented only one case of fistula formation; however, this was at the distal end of a stent introduced 10 months previously and there was a suspicion of malignancy at that site. Furthermore, when the large-diameter stents were used, we observed a significant reduction in the need for endoscopic re-intervention. This was mainly because stent obstruction, caused by tumor or granulation tissue growth at the proximal or distal end of the stent, occurred less often, with a longer median time to recurrence of dysphagia. Moreover, the migration rate of 2.2 % for the large-diameter stents was very low, even though most of them (94 %) were covered, and in 44 % of cases they had been inserted for lesions of the cardia and the distal esophagus (less than 2 cm from the cardia) and for esophagoenteric anastomosis, all of which are associated with a higher risk of migration. However, three patients with large-diameter stents had moderate to severe thoracic pain lasting more than 48 hours. Although this pain responded to analgesic therapy, we supposed that this symptom was the only one related to the higher expansile force of these large-diameter stents, especially in patients who had previously undergone radiotherapy.

In conclusion, we would recommend the use of the large-diameter Ultraflex stents, as they appear to be as safe as and more effective than the small-diameter stents in the palliation of malignant dysphagia caused by unresectable esophageal or cardial carcinomas. The latter should be reserved for those lesions with involvement of the cervical esophagus or when there is some degree of tracheal compression. However, it is our impression that at present the same conclusion does not wholly apply regarding the more rigid large-diameter Flamingo Wallstent: it has a greater expansile force and a larger upper flange than the Ultraflex (30 mm versus 28 mm), and most reported complications occurring with large-diameter metal stents have been associated with the use of this device.

Competing interests: none

References

• 1 Hasan S, Beckly D, Rahamim J. Oesophagorespiratory fistulas as a complication of self-expanding metal oesophageal stents.  Endoscopy. 2004;  36 731-734
• 2 Siersema P D, Homs M YV, Kuipers E J. Large-diameter metal stents are associated with stent-related esophageal complications.  Endoscopy. 2005;  37 600
• 3 Siersema P D, Hop W C, van Blankenstein M, Dees J. A new design metal stent (Flamingo stent) for palliation of malignant dysphagia: a prospective study.  Gastrointest Endosc. 2000;  51 139-145
• 4 Mesquita N, Silva R, Brandão C. et al . Eficácia e segurança das próteses metálicas auto-expansivas Ultraflex de maior diâmetro na patologia maligna do esófago e cárdia (abstract).  GE - J Port Gastro. 2004;  3 53