Risk factors for covered metallic stent migration in patients with distal malignant biliary obstruction due to pancreatic cancer.
OBJECTIVE
Covered metallic stents (CMSs) were developed to overcome tumor ingrowth in uncovered metallic stents (UMSs) for malignant biliary obstruction, but superiority of CMSs over UMSs is still controversial due to the high migration rate in CMS. Therefore, we conducted this retrospective analysis to clarify risk factors for stent migration, including mechanical properties of CMSs.


METHODS
Patients with unresectable pancreatic cancer, receiving CMS for distal malignant biliary obstruction in five tertiary care centers, were retrospectively studied. Univariate and multivariate analyses to identify prognostic factors for early (< 6 months) stent migration were performed using a proportional hazards model with death or stent occlusion without stent migration as a competing risk. Two mechanical properties were included in the analysis: axial force, the recovery force that leads to a CMS straightening, and radial force (RF), the expansion force against the stricture.


RESULTS
Among 290 patients who received CMS placement for distal malignant biliary obstruction, stent migration rate was 15.2%. CMS migrated early (< 6 months) in 10.0% and distally in 11.7%, respectively. In the multivariate analysis, significant risk factors for early stent migration were chemotherapy (subdistribution hazard ratios [SHR] 4.46, P = 0.01), CMS with low RF (SHR 2.23, P = 0.03), and duodenal invasion (SHR 2.25, P = 0.02).


CONCLUSIONS
CMS with low RF, chemotherapy, and duodenal invasion were associated with CMS migration from our study.
Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
Yousuke
Y
Nakai
Hiroyuki
H
Isayama
Hirofumi
H
Kogure
Tsuyoshi
T
Hamada
Osamu
O
Togawa
Yukiko
Y
Ito
Saburo
S
Matsubara
Toshihiko
T
Arizumi
Hiroshi
H
Yagioka
Suguru
S
Mizuno
Takashi
T
Sasaki
Natsuyo
N
Yamamoto
Kenji
K
Hirano
Minoru
M
Tada
Kazuhiko
K
Koike
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002779:Cholestasis / Q000209:etiology* / Q000628:therapy*; D005260:Female; D005548:Foreign-Body Migration / Q000453:epidemiology / Q000209:etiology*; D006801:Humans; D008297:Male; D008670:Metals; D008875:Middle Aged; D015999:Multivariate Analysis; D010190:Pancreatic Neoplasms / Q000150:complications* / Q000188:drug therapy; D012189:Retrospective Studies; D012307:Risk Factors; D015607:Stents / Q000009:adverse effects*; D013997:Time Factors
D008670:Metals
covered metallic stents; malignant biliary obstruction; radial force; stent migration