CAROTID ARTERY STENTING BECOMING COMPETITIVE WITH ENDARTERECTOMY
SAN ANTONIO, TX — The latest neuroprotection technologies are making stenting as safe and effective as the surgical procedure, endarterectomy, for treatment of extracranial carotid stenosis, if not more so, according to a panel of interventionalists.
“In experienced centers, carotid stenting has immediate outcomes equivalent or perhaps even superior to endarterectomy,” said Gary S. Roubin, MD, PhD, Chief of Endovascular Intervention at Lenox Hill Heart and Vascular Institute in New York City.
As experience with stenting devices matures, surgeons will not be able to match the safety and efficacy of the less invasive approach, Dr. Roubin said, in a session here at the American Stroke Association Meeting. He noted the exponential growth of cases, especially over the past 12 months. An estimated 8,000 cases have been done over the past 12 months.
Embolic protection devices have already been approved for saphenous vein grafts, he said, so busy interventional practices probably now have these devices on the shelf.
While the latest devices are more user-friendly, Dr. Roubin said there are potential downsides. For example, carotid stenting may not be advisable for patients with a carotid lesion while they are undergoing intracranial thrombolysis because of the added pressure on the brain and the increased risk of reperfusion hemorrhage.
“We are reluctant to intervene with stenting [in acute cases] unless the patient is breaking through on maximal medical treatment,” Dr. Roubin said. “We are better off waiting two weeks until the patient is stable, just as with endarterectomy.”
The field of carotid stenting has taken off since the introduction of stents made with new materials and designs. For example, the dedicated carotid nitinol stents, which are made of a nickel-titanium alloy, are slowly but surely replacing the original Palmaz design.
Michael H. Wholey, MD, Assistant Professor and Chief of Clinical Cardiovascular and Special Interventions at the University of Texas Health Science Center at San Antonio, said: “The trend today is ‘longer is better’ in a lot of centers because the nitinol stents can be used to cover the bifurcation, but from our experience, we've always shied away from using large amounts of metal. The question in stenting now is the length – should we be putting in shorter and tighter stents.”
Dr. Wholey said stent placement is getting better with the newer stents. What is not so nice is misplacement, caused when the back end of the stent jumps ahead, or because of aortic pulsations.
Dr. Wholey said the future most likely will see finer mesh in carotid stents, drug coatings to prevent restenosis, and perhaps a metal that is more crush-resistant than nitinol.
Meanwhile, there is the ongoing question about stent length.
“Are we going to pay later for covering so much today?” Dr. Wholey said. “The more we learn [about stenting], the more we realize we do not know.”
Another panelist Jay S. Yadav, MD, Director of Peripheral and Carotid Intervention at the Cleveland Clinic Foundation, said that there is no clear benefit to stenting over surgery in the acute setting, largely due to the need for antiplatelet therapy and heparin during the procedure.
In his segment of the session, Dr. Yadav said one-year follow-up of the first randomized trial of carotid stenting with a neuroprotection device in high-risk patients should be available in early 2003. He said the devices would probably be approved in late 2003 for use in high surgical-risk patients.
HOW DO NEUROPROTECTION DEVICES WORK?
Harold Adams, MD, Professor and Director of the Division of Cerebrovascular Diseases at University of Iowa Hospitals, provided Neurology Today with an explanation about how neuroprotection devices work. “Neuroprotection devices are small devices – filters or balloons – that are inserted during the angioplasty and stenting procedure. These devices are placed distally to the area of the artery that is being treated. In short, it is placed in the lumen of the artery closer to the brain.
“The purpose of the devices is to collect or trap pieces of debris or clots (emboli) that are released at the time of the angioplasty. Studies have shown that a relatively large amount of embolic material that could go to the brain is released during the procedure. The goal is to stop these emboli from reaching the brain.”