Despite use of neuroprotective devices, particles may embolize from the wall of the carotid artery and cause ischemic lesions in the brain in roughly 1 of every 4 angioplasty and stenting procedures, according to an article in the September 17th issue of the Journal of the American College of Cardiology.

"Our key finding was that ischemic lesions in the brain are seen in about 25 percent of patients despite the use of neuroprotective devices during carotid angioplasty and stenting. Thankfully, the majority of these lesions appeared to be clinically silent, that is, they were not associated with neurological symptoms," said Michael Schluter, PhD, lead author of the study.

The German researchers used before-procedure and after-procedure magnetic resonance imaging scans to observe possible effects in 42 consecutive patients (15 female, 27 male). A total of 6 types of cerebral protection systems were used; most deployed a tiny basket filter in the carotid artery downstream of the point of stenosis in order to catch any particles that embolized.

Of the 42 patients, 1 had a major stroke. In 9 other cases (including 2 procedures in the same person), magnetic resonance scans indicated that particles may have lodged in the brain and interfered with blood flow, creating an ischemic lesion that was visualized on the imaging scan. These patients had no clinically evident symptoms.

"Our study was not designed to compare the different protection devices we used. Rather, we wondered if ischemic lesions in the brain, which are indicative of loose particles having entered the cerebral circulation and occluding one or more cerebral vessels, are seen after carotid angioplasty and stenting with any neuroprotective device and to what extent," Schluter said.

Because the locations of the stroke and some of the silent ischemia cases were on the side opposite the side of the procedure, the researchers believe emboli were probably dislodged early in the procedures as the wires or catheters were being threaded toward the treatment site and before the protection devices were deployed.

"Clinicians attempting carotid angioplasty and stenting, even with neuroprotection, should be aware of this and should avoid, particularly in cases of technically difficult vessel anatomy, any prolonged attempt at accessing the target vessel. The medical industry may want to think about manufacturing less traumatic endovascular equipment," Schluter commented.

In an editorial appearing in the journal, Jay S. Yadav, MD, noted that strokes during carotid angioplasty and stenting are rare, which means that it can be difficult to measure incremental improvements in devices or procedures. He wrote that the use of magnetic resonance imaging scans in the study by Schluter and colleagues is a step toward a measurement technique that could help accelerate needed improvements in the treatment of carotid artery stenosis.

"Clearly, adequate operator experience and better sheath and guide catheters for carotid access will be mandatory for the widespread successful application of carotid stenting. Carotid access remains the most challenging part of the carotid stenting procedure, yet industry has devoted minimal resources to developing specialized access devices for the carotid," Yadav wrote.

He added, "We have made remarkable progress in developing percutaneous treatments for stroke prevention that equal or exceed surgical repair, but further improvement is possible and needed. A surrogate for clinical stroke would certainly facilitate the development and evaluation of new technology and methods for carotid stenting."