Carotid Artery Stenting

Maria Dalamagka 

According to the authors, treatment options for patients with significant carotid atherosclerosis include carotid endarterectomy (CEA), carotid artery stenting (CAS), and medical therapy. This is an analysis of results from the Stenting and Angioplasty with Protection in Patients at High-Risk for Endarterectomy (SAPPHIRE) randomized trial, which examined patients at higher surgical risk to determine factors predictive of death or stroke within 30 days of CAS. A new study gives guidance on patient features that identify patients at high and low risk for stroke or death after  carotid artery stenting - CAS. Using a population of patients at high surgical risk undergoing stenting (the SAPPHIRE worldwide study), researchers identified variables that were independently associated with higher risk, including demographic, clinical history, and lesion anatomy features, with the aim of developing a bedside tool for risk prediction. "We developed and validated a predictive model and integer-based tool to predict the occurrence of death or stroke within 30 days of CAS," Neil J. Wimmer, MD, from the Division of Cardiovascular Medicine, Brigham and Women’s Hospital, and Harvard Medical School, Boston, Massachusetts, and colleagues conclude. The tool was validated internally by statistical methods, but the investigators are also in the process of validating it externally in a new dataset, told senior author Laura Mauri, MD, also from the Division of Cardiovascular Medicine, Brigham and Women’s Hospital, and Harvard Medical School. "That being said, it's pretty robust," she said of the tool. "It's been constructed in over 10,000 patients and is already in a form that's easy to use, so we hope it will be able to be used right away by clinicians to estimate risk in individual patients." Their report was published online November 5 in Stroke to coincide with its presentation at the American Heart Association Scientific Sessions 2012 in Los Angeles, California.  The  SAPPHIRE  trial was a randomized comparison of CEA (carotid endarterectomy) vs carotid angioplasty and stenting in patients deemed at high surgical risk. However, with only 334 patients, it was not large enough to determine the features strongly associated with periprocedural risk, the authors write. For this analysis, they used data from SAPPHIRE, a single-group prospective study of higher-risk patients undergoing CAS using distal protection. The goal was to develop and internally validate a model and bedside tool to predict death or stroke within 30 days of stenting in patients at higher surgical risk by using variables that could be collected easily during clinical practice, the authors write. "The prediction model generated here can be used to support decision-making." Only patients with at least a single anatomic or comorbid factor associated with elevated surgical risk were included; in all, 10,186 patients were included in the analysis. The overall rate of stroke or death was 3.6% at 30 days after carotid stenting, which, Dr. Mauri said, is "interesting, because the patients who were included in the study were selected for having a high risk for undergoing carotid endarterectomy. And there are certain consensus opinion variables that surgeons feel increase the risk of carotid endarterectomy. Well, those variables are different from the ones that pertain to carotid artery stenting." They found that elevated age, history of stroke, history of transient ischemic attack (TIA), recent myocardial infarction (MI), the need for both cardiac surgery and carotid revascularization, dialysis treatment, the presence of a type 2 or 3 aortic arch, a right-sided carotid stenosis, a longer carotid plaque, and a severely tortuous carotid arterial system were all important risk factors for the development of stroke or death within 30 days of CAS.

·         Increased age

·         History of stroke

·         History of TIA presentation

·         Recent (<4 weeks) MI

·         Dialysis treatment

·         Need for cardiac surgery as well as carotid revascularization

·         Right-sided carotid stenosis

·         Longer carotid plaque

·         Type 2 or 3 aortic arch

·         Tortuous carotid arterial system

Using these factors, the researchers developed a model and integer-based risk score for predicting stroke or death within 30 days. The model was calibrated and internally validated, using bootstrap resampling. The risk score, included in the article, assigns points for each risk factor. The sum of the points relates to the level of risk, ranging from a less than 3% risk with 8 or fewer points to a greater than 10% risk with 16 or more points. "If you just look at the table for the risk score, the most powerful predictors obviously are the ones that give you the most points, and patients who needed to have carotid surgery together with coronary revascularization were at very high risk; patients with a recent MI, patients undergoing dialysis, those were really strong predictors, in addition to patients with advanced age, particularly those who were over 70 years of age," Dr. Mauri said.