NEW YORK (Reuters Health) – The choice between carotid artery stenting (CAS) and carotid endarterectomy remains unclear for elderly patients at risk for ischemic stroke, according to a report in the May 26th online issue of Stroke.

“We hope that our analysis provides increased confidence to physicians that CAS provides a valuable alternative to surgery to prevent stroke,” Dr. Fen Wei Wang from Creighton University, Omaha, Nebraska told Reuters Health by email. “The choice of treatment requires individualization based on the patient’s risk profile and co-morbid conditions, estimated surgical risk, and the technical issues with CAS and surgery.”

Dr. Wang and colleagues used the Medicare Provider Analysis Review and Denominator files from 2003 to 2006 to assess the relative effectiveness of CAS compared with CEA in 10,958 patients who underwent one of the procedures.

The percentage of patients who underwent CAS more than doubled between 2004 (8.2%) and 2006 (16.8%).

Patients in the CAS group were significantly more likely than those in the CEA group to be age 80 years or older and to have coronary artery disease or MI history, heart failure, renal failure, or peripheral vascular disease.

Despite their higher risk profile, patients in the CAS group had similar rates of in-hospital stroke (1.9% versus 1.4% for CEA patients) and all-cause death (0.9% for CAS versus 0.6% for CEA). Only among symptomatic patients did the in-hospital all-cause mortality and stroke risk trend higher in the CAS group.

Stroke rates did not differ significantly at 1 year (5.3% CAS versus 4.1% CEA, P=0.12), but the all-cause death rate at 1 year was significantly higher in the CAS group (9.9%) than in the CEA group (6.1%).

Patients treated with CAS had a significantly higher MI rate (4.8% CAS versus 2.5% CEA), and combined end point of death, stroke, or MI (16.7% CAS versus 11.0% CEA). Among symptomatic patients, stroke rate was higher with CAS (18.9% versus 10.3% with CEA),

In multivariate analysis, CAS was not an independent predictor of stroke, but it was associated with significantly increased risk of death, MI, and combined events compared with CEA.

“Most likely is the possibility that CAS patients were at higher baseline risk for mortality,” the researchers note. “Sensitivity analyses suggest that unmeasured confounders could account for the measured mortality difference.”

In the earlier CREST trial, the risk of periprocedural stroke was significantly higher in the CAS group, whereas mortality was similar for CAS and CEA at the 2.5-year follow-up mark.

Both studies, the investigators say, suggest that the risk of periprocedural stroke in symptomatic patients may be higher with CAS than with CEA and that “the differences in mortality outcome between CREST and the present study may be attributable to hidden biases, encouraging higher-risk patients to undergo less invasive procedure.”

“I believe both treatments have value,” Dr. Wang concluded. “New technology, pharmacology, and increased operator experience suggest that CAS will increase in frequency due to its non-surgical nature, particularly in the treatment of asymptomatic patients.”

“We will look more long-term (2 -5 years ) with a larger study sample size which will provide the opportunity to determine if one treatment provides better very long-term outcomes and, if so, in which subgroups,” Dr. Wang said.

Stroke 26 May 2011.