A review of scientific studies that compares two treatments for preventing strokes due carotid artery disease provides no clear answer on which treatment is better, writes Dr Ethan Halm, chief of the William T & Gay F Solomon Division of General Internal Medicine at UT Southwestern Medical Centre, US.
Halm’s editorial accompanies a study in the same journal written by lead author Dr Manesh Patel of the Duke Clinical Research Institute. The Patel study, which examined national data on the use and outcomes of surgery and stenting in the Medicare population, found out that the use of stenting increased 33% between 2003 and 2006, while rates of the traditional surgery dropped by 19%. The study also reported wide geographic variations in the use of the procedures.
“Given the (US) national policy interest in controlling rising health care costs, the fact that where you live may influence how much and what type of care you get as how sick you are has generated great interest,” Dr Halm said.
The carotid arteries, which run on the right and left side of the front of the neck, are two of the four main blood vessels that supply oxygen to the brain. These arteries can become narrowed by fatty cholesterol deposits, or plaque. If pieces of plaque break free, they can lodge in the brain, causing stroke. Most research on carotid artery disease focuses on two treatments to prevent stroke, surgery and stenting. The traditional method is involves opening the artery to surgically remove the plaque. Carotid stenting – a newer technique – involves inserting a mesh tube (aka stent) through the groin to keep the artery open. “The rise in use of stenting is probably due to the fact that it can be done by a much larger group of specialists compared to surgery alone and is less invasive, so more people may want it.”
However, stenting’s benefits – it requires no anaesthesia, leaves no scars and requires a shorter hospital stay – are outweighed by the fact that less is known about its long-term safety and effectiveness compared to surgery, or other procedures. It is such uncertainty that prevents the medical profession from adopting an universal approach on deciding how to treat carotid disease and patients from making a fully informed decision about how to be treated.
“Most people who have had a stroke or a ‘temporary stroke’ due to carotid disease in the past 12 months stand to benefit greatly from revascularisation if they can tolerate the procedure. People who have silent or asymptomatic carotid disease have a much more modest benefit from either surgery or stenting,” says Halm. Yet, other studies have consistently shown that surgery is better than stenting in patients of 70 years and older, the largest group with carotid disease. And although 70% to 90% of US patients who undergo surgery or stenting are asymptomatic, it also remains unproven that either revascularisation strategy is superior to the type of intensive risk factor lowering that is now possible with high-potency drugs to lower cholesterol, prevent blood clots and control blood pressure.
Dr Halm is currently developing patient education materials and an interactive computer program designed to help patients better understand the pros and cons of surgery, stenting and medical therapy. He offers the following advice to patients with carotid disease: “Ask your doctor about the potential benefits and risks of a carotid procedure given your circumstances. If you’ve had a stroke or temporary stroke in the past 12 months and over 50% of narrowing in your carotid artery, the benefits of surgery or stenting may be large. If you have had neither, you have asymptomatic carotid disease, so the benefits of revascularization are much smaller, and might not be much better than aggressive medical therapy. Treatment of asymptomatic carotid disease is not an emergency, so you have time to get the facts about the pros and cons of all three options – surgery, stenting, medical therapy alone.”