DDW Chicago 5/2011 Report Related to Stents.

Hi, Base on 5 poster sessions related to to topic” Stents “
The following is a very brief review on those posters.

1.Charles Wilcox and others in “Prospective Evaluation of the Karnofsky score as a Guide to Placing a Plastic Versus Metal Stent for Pancreaticobiliary malignancy”
Criteria used to determine stent type were: patients with liver metastases and Karnofsky score<70,and surgery is anticipated--use plastic stents (62 patients;the other(38 patients) use metallic stents.Study over a 26 months period.(100 patients total)
Overall,during following up ,27 Patients(27%) required endoscopic reintervention (21(34%)plastics stents and,6(16%) metal)
Median time to re-stent the 27 patients undergoing stent exchange was 1.5 months(range 3days to 8.7 month).
Survival was associated with liver mets and Karnofsky score but not the age of patient and the type of malignancy.

Conclusions:
The overall re-stenting rate was relatively low compared to other studies in the 27 patients they studied.The use of the Karnofsky score and liver metastases appears to be a useful PREDICTOR for survival and for the type of stent to deploy.These results have important FINANCIAL implications for endoscopic unit.
**PS. The study did not mention about the statistics about the rest of the 73 patients who might drop out of the study due to various reasons.They only mentioned the 27 patients who needed “reintervention.”

2.Atif Saleem and others performed a meta-analysis to compare stent patency and stent survival of covered self expandable metal stent (cSEMS) and uncovered SEMS(uSEMS) in patients with unresectable,malignant ,distal biliary obstruction by comprehensive search of several data bases from earliest inclusive dates to Nov.2010.(780 patients ,length of follow up=212 days.)
Conclusion:
1.This meta-analysis show covered self expandable metal stent(cSEMS) has a significantly PROLONGED patency than uncovered SEMS.
2. When re-obstruction(stent survival) occurs,there is a trend it is delayed when cSEMS are used.
3.Re-obstruction after cSEMS placement is more likely due to tumor OVERgrowth,sludge and stent migration while with uncovered SEMS is due to tumor INgrowth.
## PS. The study implied covered self expandable metal stent last longer.

3.Masakuni Fujii and others deployed multiple metallic stents(MS) with a partial stent-in stent procedure in the patients who had hilar biliary strictures caused by biliary tract carcinoma.In the 9 hilar CC patients who survived more than 2 years;all of them received Gemzar or S-1(a combination of oral chemo medications) as chemotherapy.
The median survival time was 948 days ; the mean patency time of the metal stent was 388 days(49-1590 days);seven of the nine caused MS obstruction.
The median interval between the first MS deployment and the second hospitalization was 397 days(12-1566 days)
Conclusion:
It is suggested that the initial LONG patency time of multiple metallic stents contributes to the maintenance of their favorable performance state.
Patients with the deployment of multiple metallic stents in the hilar biliary strictures,when response to chemo can live more than 2 years with favorable quality of life.
## PS.This study started with 61 patients and they only used the data for patients who responsed to chemo treatment and lived for more than 2 years.

4.Everson L. Artifon and others tried to evaluate the efficacy of multiple polyethylene plastic stent(PE) versus covered self expandable metal stent(cSEMS) for treatment of post-operative common bile duct(CBD) strictures. They studied 24 patients( divided into 2 groups of 12 patients each) from 2003-October 2010 and follow up at least 5 years.
PE stents were replaced as clinically necessary and removed after 6 (SIX)month while cSEMS were removed after 3 (THREE)months.The rates of symptomatic improvement were similar in both groups.CBD using PE and cSEMS was successful in all patients.
However post procedure patients in the cSEMS group were more likely to have a GREATER CBD median sustained expansion in the area of previous stricture (9.1mm vs.6.2mm) and a longer symptom-free period than patients treated with plastic stents.
Conclusion:
In a long term follow up(higher 5 years),treatment of benign biliary strictures using temporary covered self expandable metal stents is more effective than on-demand exchange of multiple plastic stents(the dominant strategy).The sustain expansion was better in the cSEMS group.
## PS. Please notice the study was for benign biliary strictures and the removal period was 3 months less in the cSEMS group than the PE group; and they did not mention how many plastic stents they had replaced “as clinical necessary” suggesting longer patency for the cSEMS as well.

5.Jie-Hyun Kim and others tried to investigate the safety and efficacy in drug delivery of paclitaxel-eluting stent using nano particles in biliary tract .A stent coated with 10% paclitaxel , pluronic F-127 and polyurethane was placed in the bile duct of PIGS (not human).
Conclusion:
The new paclitaxel-eluting stent using 10% pluronic F-127 is safe with enhanced local drug delivery and antitumor effect.
##PS. This study is related to the future development of new drug delivery system involved stents.

I hope the above info. helps.
God bless.