Carotid artery stenting is associated with twice the incidence of postoperative stroke and in-hospital mortality seen with carotid endarterectomy, Dr. James T. McPhee and colleagues reported.
The disparity in outcomes is even greater among patients with symptomatic stenosis, who faced a fourfold increase in stroke and a sevenfold increase in mortality after stenting, compared with endarterectomy (J. Vasc. Surg. 2007;46:1112–8).
These conclusions suggest that carotid artery stenting is not ready for wide application, wrote Dr. McPhee of the University of Massachusetts, Worcester, and his coauthors. “Further randomized controlled studies with homogenous symptomatic and asymptomatic cohorts should be performed to determine what role carotid artery stenting will play in the treatment of patients with carotid stenosis.”
The investigators drew their information from the Healthcare Cost and Utilization Project's 2003 and 2004 Nationwide Inpatient Sample database. During those two years, 259,000 carotid revascularization procedures were performed in the United States. Most (95%) were endarterectomy; the rest were stenting procedures. Almost all of the patients (92%) had asymptomatic stenoses. The patients' mean age was 71 years; however, the 8% of patients with symptomatic stenoses were significantly older (75 years).
The postoperative stroke rate for all patients was 1.8% after stenting and 0.9% after endarterectomy. A multivariate analysis identified stenting as an independent risk factor for both stroke (odds ratio 2.5) and in-hospital mortality (OR 2.4).
When the investigators examined symptomatic patients only, they found even more profound differences. Among these patients, the postoperative stroke rate after stenting was four times higher than it was after endarterectomy (4% vs. 1%). Symptomatic patients were seven times more likely to die in the hospital after stenting than after endarterectomy (7.5% vs. 1%).
The study adds to the already conflicted body of data on the safety of carotid artery stenting, Dr. McPhee and his coauthors wrote. While several independent studies have found an increased risk of stroke and death with carotid stenting, industry-sponsored registries have concluded that the technique is noninferior to endarterectomy. “[These studies] have been criticized by others because of their methodology … the power of the study, and the validity of a noninferiority study on nonrandomized data using a historical control for the surgical arm,” the authors wrote.
The study provides a valuable insight into this confusing picture, said Dr. Wesley S. Moore, professor and chief emeritus of vascular surgery at the University of California, Los Angeles. “This analysis represents actual, everyday practice data in contrast to very selective clinical trials and registries, most of which are industry sponsored, suffer from design flaws, and are open to criticism for lack of objectivity because the industrial sponsor has control of the data and is unlikely to publish unfavorable results,” Dr. Moore said in an interview.
Critics of the McPhee study may note that carotid stenting is an evolving technique, and that newer safety data will probably be better than those seen in 2003 and 2004, Dr. Moore said. “While this may be true, it is also important to point out that two prospective randomized controlled European studies—not industry supported—have reported similar results in favor of endarterectomy.”
Indeed, he said, because carotid stenting is still a relatively new procedure, “It should only be used in well-designed, objective clinical trials that will yield meaningful data, as opposed to so-called clinical registries, which only serve to skirt federal regulations and permit the unmonitored use of a yet-to-be proven procedure.”
Finally, Dr. Moore said, data have yet to emerge regarding the comparative durability of the two techniques. “We currently have a large prospective randomized controlled study, supported by the National Institutes of Health [CREST or the Carotid Revascularization Endarterectomy vs. Stenting Trial], which is nearing completion of patient acquisition. Once that trial is complete, with 5-year follow-up, we should then have a final word as to the relative safety and benefit of the two procedures.”
Dr. McPhee and his associates stated that they have no financial conflicts of interest.
Angiogram shows a narrowing of the internal carotid artery (near the center of the image).
A completion angiogram, taken after stenting, shows that the stenosis has been treated. PHOTOS COURTESY OR-LIVE.COM