Alternative to radiation in preventing restenosis

["Jacobus, John (OD/ORS)" <jacobusj@ors.od.nih.gov>]

Since the topic of radiation use in preventing restenosis came up, I thought

the following may be of interesting.  If the clinical trials show favorable

outcomes over the long-term , the use of radiation in the treatment of

restenosis will eventually disappear.  (Who wants to go through the hassle

of radiation delivery system, when you can use a chemically coated stent?)



-- John



John Jacobus, MS

Certified Health Physicist 

3050 Traymore Lane

Bowie, MD  20715-2024



E-mail:  jenday1@email.msn.com (H)      



FROM:  Diagnostic Imaging Online

January 24, 2002



Drug-eluting stents stave off restenosis in early trial 



Cardiologists were stunned at the American Heart Association in November

when early trial results indicated that Sirolimus-eluting coronary artery

stents may offer a definitive solution for restenosis. 

Now, it's time for interventional radiology to be impressed. The same 0%

restenosis rates that raised eyebrows at the AHA meeting appeared again

Tuesday in a pilot study of Sirolimus-eluting stents presented at the

International Symposium on Endovascular Therapy in Miami. This time the

anatomy targeted was the superficial femoral arteries, a region so notorious

for in-stent restenosis that many interventional radiologists consider stent

placement there a waste of time. 



This reluctance may change if the results of the SIROCCO trial are repeated

in larger studies. The prospective, double-blinded study was conducted by

Dr. Stephan Duda, vice chair of radiology at the University of Tuebingen in

Germany. It tracked the clinical experience of 36 severely claudicated

patients at one Canadian and five European hospitals: 



18 patients were treated with Cordis self-expanding, nitinol SMART stents

coated with a polymer impregnated with Sirolimus, a naturally occurring

antibiotic that inhibits smooth muscle cell proliferation 

18 controls received uncoated SMART stents 

Although the SIROCCO trial was randomized, the small sample size may have

skewed patient populations. All of the lesions treated in the Sirolimus

branch were calcified, compared with only 47% of the ischemia in the control

group. The Sirolimus groups also included a disproportionate share of

smokers and diabetic patients. 



This may be why the control group did unexpectedly well. The binary

restenosis rate after six months among patients equipped with the uncoated

stents was 23.5%. In-stent restenosis was 17.6% among the controls when the

expected restenosis rate for this group was 40% to 50%, according to Duda. 



The performance of the Sirolimus-coated stents was even better. The binary

restenosis rate, which accounted for the accumulation of intimal hyperplasia

around the stent and 0.5 mm upstream and downstream from the stent was 0%,

as was the in-stent restenosis rate. Late loss, a measure of minimal luminal

diameter immediately after stenting and six months later, was 0.46 mm in the

Sirolimus group and 0.8 mm among the controls. 



Statistical significance was achieved on only one measure because the

controls performed so well. The mean stent diameter in the Sirolimus group

was 4.95 mm after six months compared with 4.31 mm in the uncoated stent

group. 



The SIROCCO trial achieved two historic firsts, according to Duda. It was

the first pilot study to evaluated the performance of a drug-eluting stent

outside the coronary arteries, and it was the first study of a Sirolimus

coating of a self-expanding stent. Although observers would have like to

seen more statistical significance, the results were encouraging. 



"SIROCCO lived up to its early expectations," said Michael R. Jaff, director

of vascular medicine at The Heart and Vascular Institute of New York. "The

trends in everything you saw there today was very positive for Sirolimus." 



By James Brice 



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