Carotid Stenting Linked to More Intracranial Hemorrhages Than Endarterectomy

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Patients requiring revascularization for carotid stenosis are more likely to develop intracranial hemorrhage and other unfavorable outcomes with carotid artery stenting (CAS) than with carotid endarterectomy (CEA), according to findings from a national database. In the study, published online August 11, 2011, ahead of print in Stroke, researchers found that younger, symptomatic patients were particularly prone to hemorrhage after CAS.

Robert J. McDonald, MD, PhD, of the Mayo Clinic (Rochester, MN), and colleagues examined data on postoperative cases of intracranial hemorrhage in 215,012 patients who underwent CEA and 13,884 who underwent CAS and were included the National Inpatient Sample database from 2001 to 2008. Data included clinical presentation (asymptomatic vs. symptomatic), discharge status, in-hospital mortality, demographics, and hospital characteristics.

Only 5% of patients were symptomatic. CEA significantly outnumbered CAS in both symptomatic (89% vs. 11%) and asymptomatic patients (94% vs. 6%). However, symptomatic patients received a higher proportion of CAS procedures compared with asymptomatic patients (10% vs. 5%; P < 0.0001). While there were no differences in age between symptomatic and asymptomatic patients in the CEA group, among those who underwent CAS, symptomatic patients were younger than those who were asymptomatic (median age, 65 years vs. 72 years; P < 0.0001).

Symptomatic Patients at Higher Risk

Intracranial hemorrhage occurred more frequently after CAS than CEA in both symptomatic and asymptomatic patients. In addition, in-hospital mortality was substantially higher among symptomatic patients receiving CAS (table 1).

Table 1. Symptomatic Patients

 
CAS patients younger than 70 years who were symptomatic had higher rates of intracranial hemorrhage than their same-age symptomatic counterparts who received CEA (5.0% vs. 0.9%) and compared with same-age asymptomatic patients (5.0% vs. 0.4%). In all other subgroups, however, patients 70 years or older had higher rates of intracranial hemorrhage relative to younger patients.

In multivariate regression analysis, CAS patients were 6 times more likely to have postoperative intracranial hemorrhage (OR 6.07; P < 0.0001) and almost two-thirds more likely to experience in-hospital mortality (OR 1.63; P < 0.0001) compared with CEA patients. In addition, symptomatic patients were more likely to experience intracranial hemorrhage (OR 6.81), die during hospitalization (OR 5.09), or have unfavorable discharges (OR 7.22; all P < 0.0001) than asymptomatic patients regardless of treatment.

Moreover, intracranial hemorrhage predicted a 30-fold increased risk of mortality before discharge (OR 29.83; P < 0.0001).

Findings Unexpected

According to the study authors, the finding that symptomatic presentation, particularly among younger patients treated with CAS,  substantially increased the risk of intracranial hemorrhage relative to symptomatic presentation in patients treated with CEA and to asymptomatic presentation in general was unexpected.

Since symptomatic CAS recipients tend to be younger and have fewer comorbidities than their counterparts receiving CEA, it appears that the excess risk of hemorrhage may not be a function of advanced age or disease, the investigators point out.

The researchers offer a possible explanation. Intracerebral hemorrhage is thought to be a result of cerebral hyperperfusion syndrome, a condition arising from dysregulation of cerebral blood flow and free radical–mediated endothelial damage in the preoperative chronically hypoperfused state. CAS procedures may be more likely to result in postoperative hyperperfusion, they suggest.

“These results strongly argue for judicious use of CAS among symptomatic presentations because adverse outcomes are more common, particularly in this subgroup, regardless of patient demographics or clinical characteristics,” they write.

The findings are in line with a recent report from the CREST (Carotid Revascularization Endarterectomy versus Stenting Trial) group, which showed that aggregate risks for periprocedural stroke and death were higher for CAS than CEA patients who presented with symptomatic disease. However, the study authors point out that the CREST researchers did not specifically address hemorrhage as an outcome, nor did they attempt to drill down into the combined event rates of periprocedural death and stroke.

Was Higher Rate of Hemorrhage Missed in CREST?

In a telephone interview with TCTMD, Dr. McDonald said the study came about based on one of his co-authors’ experience with a patient who developed intracranial hemorrhage after CAS.

“We knew that this was something that wasn’t well studied and we had an interest in trying to find out how common it was,” he said.

Dr. McDonald said the message of the study is not that carotid stenting is unsafe but rather that there are differences between CAS and CEA in terms of clinical outcomes that may not have emerged yet, even from trials such as CREST.

“That was a very large and well-conducted study, but it is possible that this was missed,” he said.

Dr. McDonald added that while the NIS database is a good starting point from which to look at the occurrence of intracranial hemorrhage, the findings should spur further prospective studies to try to understand why bleeding in the brain may be occurring more often with stenting.

Database, Comparator Issues

In an editorial accompanying the study, CREST researchers Wayne M. Clark, MD, of Oregon Health and Science University (Portland, OR), and Thomas G. Brott, MD, of the Mayo Clinic (Jacksonville, FL), point out a potential problem with the NIS database: differences in the ICD codes.

Overall, 41% of the intracranial hemorrhages included in the study had an ICD code of 430, which is subarachnoid hemorrhage, a rare and much less frequent occurrence after CAS and CEA than intracranial hemorrhage.

Drs. Clark and Brott add that since CAS reimbursement during the study period required that patients either be enrolled in a registry trial or be considered at high risk for CEA, “their study is likely comparing a predominantly high-risk surgical population (CAS) to a predominantly standard-risk population (CEA).”

Therefore, the editorial says, the high risk may explain the higher in-hospital mortality and unfavorable discharges. Whether these same preexisting features also influence the rate of intracranial hemorrhage, however, is unknown. The editorial concludes that the study “raises appropriate concerns.”

 

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Source:
McDonald RJ, Cloft HJ, Kallmes DF. Intracranial hemorrhage is much more common after carotid stenting than after endarterectomy: Evidence from the National Inpatient Sample. Stroke. 2011;Epub ahead of print.

 

 

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