Clinical outcomes of nitinol and stainless steel uncovered metal stents for malignant biliary strictures: is there a difference?

doi:10.1016/j.gie.2010.08.035

Gastrointestinal Endoscopy

Volume 72, Issue 6, December 2010, Pages 1195-1200

https://doi.org/10.1016/j.gie.2010.08.035 Get rights and content

Background

Self-expandable metal stents (SEMSs) made from nitinol (N) were developed as a potentially more effective alternative to conventional stainless steel (SS) stents.

Objective

To compare clinical outcomes of N versus SS stents in the management of malignant biliary strictures.

Design

Retrospective study.

Setting

Tertiary-care cancer center.

Patients

All patients with first-time N (Flexxus) and SS (Wallstent) uncovered biliary SEMSs placed between January 2006 and October 2007.

Interventions

SEMS placement.

Results

A total of 81 N and 96 SS stents were placed. The most common cancer diagnosis was pancreatic (80.2% N; 62.5% SS; P = .06). The most frequent site of stricture was the common bile duct (85.2% N; 86.5% SS; P = .31). Biliary decompression was achieved in 93.8% of the N group and 86.4% of the SS group (P = .22). Immediate stent manipulation was required in 4 patients in each group. Subsequent intervention for poor drainage was performed in 17 N (21%) and 26 SS (27%) stents at mean times of 142.1 days (range, 5-541 days; median, 77 days) and 148.1 days (range, 14-375; median, 158.5), respectively (P = .17). The occlusion rate between N and SS stents was not significant (P = .42). The overall durations of stent patency in the N and SS group were similar (median 129 and 137 days, respectively; P = .61), including the subgroup analysis performed on patients with pancreatic cancer (P = .60) and common duct strictures (P = .77). Complication rates were low in both groups (early: 3.7% N, 6.3% SS; late: 2.5% N, 3.1% SS). Ninety percent underwent chemotherapy and 38% radiation therapy in each group.

Limitations

Retrospective design.

Conclusion

Similar outcomes were achieved with N and SS stents regarding efficacy, duration of stent patency, occlusion rates, and complications. Our results are most applicable to patients with common duct strictures and pancreatic cancer.

Section snippets

Methods

The study was approved by the M. D. Anderson Cancer Center Institutional Review Board. Review of all uncovered SEMSs placed between January 1, 2006, and October 31, 2007, was performed. The majority of the strictures in the study were located in the common ducts and not intrahepatic ducts; decision as to which stent was to be placed in any given situation was not randomized and was left to the discretion of the endoscopist considering the location and complexity of the strictures. The primary

Results

A total of 81 N and 96 SS uncovered metal stents were placed during the period. Six patients in the N group and 8 patients in the SS group had 2 (tandem or bilateral) uncovered metal stents placed. A summary of demographic data is provided in TABLE 1, TABLE 2. The most common cancer diagnosis was pancreatic cancer: 70.2% of all patients (80.2% in the N group and 62.5% in the SS group; P = .06). Hepatic metastases were present in 54.3% of the N group and 44.8% of the SS group (P = .21).

A summary

Discussion

Our results demonstrated no significant advantage of one stent over the other. Similar performance, as determined by duration of stent patency and stent occlusion rates, was seen. Given the distribution of our data, these findings would appear to apply mostly to pancreatic cancer patients with common bile duct strictures. Our results suggest that both stents are largely interchangeable for the management for these types of strictures. No clear survival benefit or improved performance (patency

Conclusion

Similar rates of performance and outcomes were achieved between N and SS stents regarding stent patency and occlusion rates, especially for the management of common bile duct strictures in patients with pancreatic cancer. However, the lack of a difference in clinical outcome between the 2 groups should be interpreted with the limitation of the small sample size. No perforations or fistulous complications were observed in patients undergoing chemoradiation for pancreatic cancer with metal stents

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The common materials used for metal biliary stent includes nickel titanium alloy wire, stainless steel wire, tantalum wire and so on, which could guarantee enough supporting force without sacrificing the bending and compliance (Chun et al., 2010). Weston et al. (2010) and Yang et al. (2009) compared the clinical efficacy resulted by different material composition stent and found that there is no obvious difference in long-term patency and complication, but the metal stent structure has some influences on the clinical efficacy, Loew et al. (2009) analyzed the curative effect of “Zilver” and “Walstent” stent with different diameter, and obtained that “Zilver” stent with smaller diameter results in higher restricture rate. The metal biliary stents have advantage in long-term patency, low migration rate, improving life quality and decreasing therapy cost compared with plastic biliary stent (Lammer et al., 1996; Guo et al., 2001).
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: DISCLOSURE: All authors disclosed no financial relationships relevant to this publication.

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Original Article: Clinical EndoscopyClinical outcomes of nitinol and stainless steel uncovered metal stents for malignant biliary strictures: is there a difference?

Background

Objective

Design

Setting

Patients

Interventions

Results

Limitations

Conclusion

Section snippets

Methods

Results

Discussion

Conclusion

Am J Gastroenterol

Am J Gastroenterol

Gastrointest Endosc

Lancet

Gastrointest Endosc

Gastrointest Endosc

Clin Gastroenterol Hepatol

Original Article: Clinical Endoscopy
Clinical outcomes of nitinol and stainless steel uncovered metal stents for malignant biliary strictures: is there a difference?