Proximal balloon superior to distal protection in carotid artery stenting

For those needing their arteries cleaned out, read for stroke prevention strategies so you can ask your doctor.
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Proximal balloon occlusion provides significantly greater embolic protection during carotid artery stenting (CAS) for internal artery stenosis when compared with a filter protection device, research shows [1]. Proximal balloon-occlusion devices do not cross the lesion before it is stented, which helps to significantly reduce embolic load in the brain during the carotid procedure, according to researchers.

To heartwire, senior investigator Dr Joachim Schofer (University Cardiovascular Center, Hamburg, Germany) said that while the question can't be answered clinically from these data, he believes there is connection between the asymptomatic "spots" observed on diffusion-weighted magnetic resonance imaging (DW-MRI) in their study and the risk of stroke. "I'm pretty convinced that proximal balloon occlusion is more effective than distal protection and would result in a lower rate of stroke," he said.

The results of the study, known as the Prevention of Cerebral Embolization by Proximal Balloon Occlusion Compared to Filter Protection During Carotid Artery Stenting (PROFI), are published online January 25, 2012 in the Journal of the American College of Cardiology.

Spots on the brain

The study included 62 consecutive symptomatic and asymptomatic patients undergoing CAS with embolic protection who were randomly assigned proximal balloon occlusion (MO.MA, Invatec) or filter protection (Emboshield Protection System, Abbott Vascular). Compared with the filter, which crosses the lesion before the stent is implanted and is deployed to catch debris during the procedure, the balloon-occlusion device is placed proximal to the lesion and inflated to occlude the external and common carotid arteries. Flow is reversed in the target vessel before the lesion is crossed and treated.

Using DW-MRI, the researchers found that the incidence of new cerebral ischemic lesions per patient was significantly greater among patients who underwent distal protection (87.1% in the filter group vs 45.2% in the balloon-occlusion group; p=0.001). The incidence of new ischemic lesions was significantly higher with filter protection in symptomatic and asymptomatic patients, and there was a trend toward more lesions in patients >80 years of age. Regarding the secondary end points, the researchers report that the number of lesions per patient and the volume of lesions per patient were significantly higher among those who received the filter device compared with balloon occlusion.

One patient had a minor stroke in the filter-protection group, while no major adverse cardiovascular or cerebrovascular events (MACCE) were observed in the balloon-occlusion patients. Schofer noted, however, the study is underpowered for clinical events.

Schofer told heartwire that filter-protection devices are relatively easy to use, and the risk they pose is related to the crossing of the lesion, which results in some dislodging of emboli. In addition, some particles might be too small to be captured by the filter or might pass by the filter if it is not placed properly against the vessel wall. The filters can also become overloaded, which can cause some debris to spill during retrieval. The proximal balloon-occlusion device does not have similar downsides, although it is slightly harder to use and does require more training, said Schofer.

Not all patients are good candidates for proximal balloon occlusion, either. Patients with contralateral occlusion were not included in this study, but balloon intolerance was still noted in 13% of patients. Contralateral new ischemic lesions that develop are likely caused by emboli dislodged when the catheters navigate through the aortic arch, said Schofer.