New Imaging Technology Could Help Physicians Tailor Stroke Prevention Efforts
What if you could look inside your blood vessels and predict whether you were going to have a stroke? A study conducted at Baptist Health Lexington looked at just that question using a new tool called Optical Coherence Tomography (OCT). The ability to literally peer into the composition of any plaque – the fatty build-up that can obstruct the blood vessels that feed the brain and cause a stroke – is now available. This technology has the potential to alter how physicians understand and treat carotid artery disease, which is one of the leading causes of strokes.
The study, conducted between September 2010 and May 2012, was featured in the June 2014 issue of the prestigious Journal of the American College of Cardiology (JACC) Cardiovascular Interventions. Interventional cardiologist Dr. Michael R. Jones served as a principal investigator of the study, which also included neurosurgeons Dr. William H. Brooks and Dr. Christian N. Ramsey, neurointerventional radiologist Dr. Curtis A. Given II, along with physicians from Case Western Reserve University in Cleveland, Ohio, and Pitangueiras Hospital in Jundiai, Brazil.
The study involved a retrospective review of 53 patients suspected of having carotid artery stenosis, a narrowing caused by the build-up of plaque. The patients underwent diagnostic carotid angiography, a standard imaging technique used to detect carotid artery stenosis. They also underwent OCT, a new, high-frequency imaging technique that creates images 10 times clearer than older imaging techniques.
Patients involved in the study were either symptomatic – had experienced symptoms suggestive of a stroke – or were asymptomatic – had experienced no symptoms suggestive of a stroke but were considered at high risk for a stroke due to certain risk factors.
“Because OCT offers such high resolution images of the walls of blood vessels, we were able get an extremely clear look at the type of plaque and identify some of it as ‘vulnerable’ or ‘unstable’ plaque,” explained Jones.
Physicians have suspected for a while that some plaque is stable and some unstable and inflamed. It is the unstable plaque that is at risk for rupture. That rupture on the inside of the blood vessel is then treated like a wound by the body. One of the first things that occur in wound healing is that a blood clot is formed to stop any bleeding. Thus, the body forms a blood clot on the ruptured plaque. This clot then can be dislodged from the plaque and travel to the brain causing a stroke. Less commonly, the fatty substance itself can break off and travel to the brain.
The study revealed that symptomatic patients had a larger percentage of unstable or vulnerable plaque but actually less blockage when compared to the plaque found in vessels of asymptomatic patients.
It has long been thought that opening carotid arteries severely narrowed by plaque – either with surgery or a stent – is one of the most effective ways to prevent stroke. “This study, for the first time ever, was able to reveal that severity of the narrowing was not as much of a predictor of a stroke as the composition of the plaque itself,” said Jones
“This study, along with others that are sure to come in the future, could change the way we test patients with carotid artery disease,” Jones said. “It could be that they might be better served with looking at the type of plaque they have rather than by measuring the severity of their blockage.”
A complimentary editorial accompanying this publication calls the research “pioneering” and adds that investigators “expand our knowledge of the carotid artery microenvironment, providing important insights regarding carotid stenosis quantification and plaque characterization.”
Baptist Health Lexington has developed an impressive reputation for its carotid artery disease research studies. It is one of only a few places in the world that is doing this type of groundbreaking research.
“We’re not an academic medical center, but we still can produce this caliber of cardiovascular and neurological research, said Jones. “Not only does it speak to the superior neurological and cardiovascular services that are available at Baptist Health Lexington, but it also brings attention to the hospital’s commitment to seeking better treatments for its patients who will ultimately benefit from this research.”