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Imaging evidence of a marker linked to new brain injury is not uncommon after carotid revascularization with either endarterectomy or stenting, according to a study published online December 17, 2013, ahead of print in Stroke. Half of patients found to have the marker, which indicates disruption of the blood-brain barrier, also had new neurological deterioration.

Lead author Dong-Wha Kang, MD, PhD, of the University of Ulsan College of Medicine (Seoul, South Korea), and colleagues conducted a prospective study of 45 patients who underwent carotid endarterectomy (CEA; n=29) or carotid artery stenting (CAS; n=16) between July 2007 and December 2009.

Brain scans were obtained with magnetic resonance imaging (MRI), including diffusion-weighted imaging (DWI) and fluid-attenuated inversion recovery (FLAIR) before and after the procedure. To detect the hyperintense acute reperfusion marker, investigators intravenously injected gadolinium immediately postprocedure.

The marker was not observed on FLAIR in any patients prior to the procedure, but was seen in 8 (17.8%) postprocedure.  Of these, 4 (50%) experienced worsening neurological symptoms, but steadily improved after strict blood-pressure control. On follow-up MRI, symptomatic patients showed no further evidence of the marker, which was associated with older age, white-matter abnormalities (leukoaraiosis) and postprocedure hypertension (table 1).

Table 1. Risk Factors Associated with Symptomatic Markers

Postprocedure DWI revealed new infarcts in 8 CEA patients (27.6%) and 5 CAS patients (31.3%). Only 2 patients experienced neurological worsening due to these new infarcts, and evidence of the reperfusion marker was not associated with their presence (P = 0.20). Of the 8 patients with the reperfusion marker, 4 had new infarcts, with ischemic lesions usually located in the area of the marker.  

“It is interesting to note that symptomatic [hyperintense acute reperfusion marker] (50%) was more frequent than new symptomatic lesions (15%) in this study,” the study authors write. “We think that [the marker] could be considered a major cause of neurological complications after carotid revascularization.”

An Underdiagnosed Marker

Although the reperfusion marker has been studied in patients with acute ischemic stroke, little is known regarding its incidence and associated risk factors in patients undergoing carotid revascularization, Dr. Kang said in an e-mail communication with TCTMD. 

In a telephone interview with TCTMD, Steven Burstein, MD, of Good Samaritan Hospital (Los Angeles, CA), said that based on the study findings, symptomatic hyperperfusion syndrome or reperfusion injury is probably underdiagnosed in this patient population.

Additionally, while the number of patients undergoing elective carotid revascularization studied was small, subjects with the marker in the absence of stroke did not experience long-term sequelae, which is encouraging, reported Dr. Burstein. “It seems to be more of an inconvenience for patients,” while hyperperfusion with stroke or acute brain injury leads to poor outcomes, he said.

According to Dr. Kang, the risk factors identified in the study may be important for reducing reperfusion injury risk. Additionally, awareness of the marker and the need for careful evaluation are important when major clinical worsening occurs after carotid revascularization.

Clinically, Dr. Burstein explained symptoms associated with the hyperintense acute reperfusion marker manifest as headache and subsequent abnormal CT scan.  “On the scan, it looks as if contrast has leaked into the brain,” he said. “It’s quite different from swelling of the brain after these procedures.”

Clinical Implications Unclear

Although ordering an MRI for every patient undergoing carotid revascularization is not practical, those with any early sign of neurological symptoms or complaints, including headache, may need an MRI assessment to check for evidence of the marker, Dr. Burstein advised.

Dr. Kang added that the clinical implications of asymptomatic patients who have the marker on MRI are still unclear. “We [need to] consider that there is a broad spectrum between mild reperfusion injury, demonstrated as asymptomatic [hyperintense acute reperfusion], and hyperperfusion syndrome, demonstrated as seizure [and] hemorrhage,” he observed.

Despite the prospective nature of this study, the sample size is small, Dr. Kang acknowledged. Furthermore, whether symptomatic and asymptomatic markers can be completely reversed requires study in larger samples, he said. Although CEA and CAS were both included in the analysis, larger studies are needed to evaluate the 2 procedures separately while assessing the development of the marker, he added. 

Also of future interest is “whether strict blood pressure control is better than standard blood pressure control,” Dr. Kang concluded.

Overall, physicians need more information about, “who symptomatic [markers] occur in, if it’s dangerous[,] and what do we do to mitigate against complications,” said Burstein.

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