After angioplasty is performed to widen clogged arteries, surgeons frequently use tiny wire-mesh tubes called stents to keep blood vessels open. But despite stenting, scar tissue can form to create new blockages -- a process called in-stent restenosis (ISR). At present, vascular brachytherapy (catheter-based delivery of intracoronary radiation) is the only therapeutic modality proven to effectively reduce in-stent restenosis.
But a team of Emory cardiology researchers presented a study at the American College of Cardiology (ACC) Scientific Sessions today showing that patients with ISR treated with a sirolimus-eluting stent (SES), which releases the therapeutic agent sirolimus over time to prevent restenosis, fared at least as well as those treated with vascular brachytherapy (VB). Moreover, the patients who received the drug eluting stent had fewer cardiac events afterwards.
"The efficacy of the SES in native coronary arteries is proven -- but the safety and efficacy of drug eluting stents in the treatment of ISR is unclear. To help clarify these issues, we compared in-hospital and six month outcomes in patients with ISR treated either with SES or vascular brachytherapy (VB)," explains Emory Heart Center interventional cardiologist Peter C. Block, MD, the principal investigator of the study.
Using a retrospective non-randomized study design, the Emory team analyzed the U.S. nationwide post marketing surveillance registry maintained by Cordis (maker of the Cypher SES) which included 2063 patients implanted with Cypher SES between August of 2003 and December of 2003 -- 136 of whom had received SES for ISR.
The Emory researchers also identified 99 patients in the Emory cardiac databank who received VB as treatment of ISR between July of 2003 and January of 2004. These patients were contacted by telephone 4 to 8 months following their VB for a phone interview about their cardiac symptoms and outcomes.
Using the Cypher registry surveillance data and the Emory databank questionnaires, the researchers compared the baseline demographic variables, angiographic variables and frequencies of in-hospital and 6-month adverse events between patients who received SES or VB for in-stent restenosis.
"We found SES as treatment for ISR is at least equivalent, if not superior, to VB. There were no differences in clinical event rates at 6-month follow-up between the two treatments," says Emory Heart Center interventional cardiology fellow Fadi Alameddine, MD, lead author of the research presented at a poster session today. "However, SES was accompanied by a lower incidence of heart attacks both while the patients were still in the hospital and six months after discharge. The SES patients also had a lower rate of in-hospital total higher major adverse cardiovascular events."
Conventional VB treatment, which is a logistically demanding procedure, exposes patients to radiation and is associated with a risk of late restenosis (20 to 40 percent) and late thrombosis. However, whether SES is superior to VB long-term remains an open question, according to Dr. Alameddine. "That will be addressed by ongoing prospective randomized controlled multi-center studies. We should have those results in about six months," he notes.
Dr. Block disclosed a commercial relationship with Cordis-Johnson & Johnson.