Dr. Lal and his associates plan to further analyze their data and derive a formula that physicians can apply to patients to estimate their periprocedural stroke risk.
Additional, recent CREST analyses that were also reported at the International Stroke Conference revealed other new, important lessons about CAS and CEA.
First, by 2 years after intervention, both CAS and CEA produced roughly comparable low rates of restenosis: a 6.0% rate in the CAS patients who underwent a prespecified, follow-up duplex ultrasound examination of their carotid artery, and 6.3% in the CEA patients (Stroke 2012;43: abstract A3). The rates were also similar regardless of whether patients were symptomatic before their carotid intervention, Dr. Lal reported.
This finding appears to lay to rest the concern about a major restenosis risk using bare-metal stents in carotid arteries, in contrast to what happens in coronary arteries, Dr. Lal said. "To my mind, these data are fairly definitive. We followed more than 2,000 patients, and every ultrasound was reviewed and adjudicated. I’m fairly comfortable with these results."
A third CREST analysis that was also reported in February showed that, after adjustment for baseline differences, patients had no significant changes in their rates of periprocedural events during and after CAS throughout the study, from 2000 to 2008 (Stroke 2012;43: abstract A1). "We hoped to show that CAS was getting better [during the 9 years of CREST], but we saw no evidence it got better with time," said George Howard, Dr.P.H., professor and chairman of the department of biostatistics at the University of Alabama at Birmingham. "It would make sense if CAS got better; it’s a new procedure that people learn." But the CREST results showed no evidence of a learning curve, perhaps because the 224 interventionalists who performed CAS in CREST went through a rigorous credentialing process and also performed their first several CAS procedures in CREST during a lead-in phase that was not included in the main outcomes.
Choosing Among the Options
Dr. Lal said that he draws several other lessons from the CREST results to guide his treatment decisions: Patients who are physiologically elderly, those with a large amount of calcified atheroma in their aortic arch, and patients with significant peripheral arterial disease that impedes endovascular access are all poor CAS candidates, he said, adding that he focuses on a patient’s physiological age rather than chronological age.
Photo courtesy University of Maryland Medical Center
In recent years, medical treatment of carotid stenosis has improved to the point that many vascular surgeons use it in nearly all their asymptomatic patients.
Patients who are well suited to CAS are those with a younger physiological age, those with a history of radiation treatment, and patients with restenotic carotid lesions.
Although CREST showed worse performance of CAS in women compared with men, "I don’t know why, so it’s hard for me to exclude or offer a particular treatment" based on the patient’s sex, he said. "I treat women just like men, and work through all the other things that I know about to help me decide."
Then there is a third subgroup, patients with carotid disease who he feels "benefit the most" from medical management only. This category primarily includes asymptomatic patients with moderate stenosis (that is, less than 80% carotid occlusion). His prescription for medical management includes 325 mg of aspirin daily, treatment with a statin, good blood pressure and blood sugar control, smoking cessation, and lifestyle modification. If, despite this, an asymptomatic patient has continued stenotic progression that advances beyond 80%, he will then recommend revascularization.
Dr. Lal said that in his practice today, roughly one-third of carotid-disease patients are on medical management, a third undergo CEA, and a third receive CAS. "We are at a stage of equipoise," for these three options, which is why he helped design and is working to get funding for CREST II.
Dr. Lal personally applies all three treatment options – CAS, CEA, or medical management. Having physicians involved in the decision-making process who are comfortable using each of these options is critical for making a balanced management decision, said Dr. L. Nelson Hopkins, another CREST collaborator and professor and chairman of neurosurgery at the State University of New York at Buffalo.
"The single most important thing we do is have a weekly, multidisciplinary conference to discuss each case, with input from everyone, to decide the best treatment for each [carotid disease] patient," he said when he spoke at ISET 2012, an International Symposium on Endovascular Therapy in Miami Beach in January.