German Registry Shows Trends in CAS Practice, Outcomes Over 15 Years

Patients undergoing carotid artery stenting (CAS) are less apt to experience in-hospital death or stroke than they were in the past, according to data from a German registry spanning 15 years. The study, published online November 13, 2014, ahead of print in the American Journal of Cardiology, also found that the patient population is simultaneously growing older and more asymptomatic.

The authors attribute these positive trends to “growing experience” and the routine use of embolic protection devices.  

Nicolas Werner, MD, of Klinikum Ludwigshafen (Ludwigshafen, Germany), and colleagues prospectively analyzed 6,116 CAS procedures in 5,976 patients at 36 hospitals enrolled in the nationwide German ALKK registry from February 1996 to December 2010.

Average patient age was 71 years, 71.6% were men, and half were symptomatic. Baseline prevalence of CAD was 65.5%, prior MI 25.8%, and PAD 25.1%. Overall, 97.6% of patients actually received stents. Embolic protection devices were used in 82.5% of all procedures, and median hospital stay after CAS was 2 days.

Procedural, Patient Characteristics Shift Over Time

The vast majority of patients were prescribed dual antiplatelet therapy with aspirin and clopidogrel. Vitamin K antagonists were prescribed in 5.5%, and 82.7% of patients were discharged on statins.  

In-hospital death or stroke (primary endpoint) occurred in 3.1% of patients, with death reported in 0.5% and ipsilateral stroke in 2.3%. Incidence of the primary endpoint was higher in symptomatic than asymptomatic patients (4.0% vs 2.2%; OR 1.86; 95% CI 1.36-2.56; P < .001).

In a logistic regression model, independent predictors of the primary endpoint included heart failure, symptomatic stenosis, and older age. Use of an embolic protection device was associated with a lower risk of in-hospital death or stroke (table 1).

  

Patient and procedural characteristics shifted over the study period. Mean patient age increased by 4.1 years from 1996 to 2010 (P < .001). Additionally, the main indication for CAS switched from symptomatic stenosis in the late 1990s to asymptomatic disease in more recent years (P < .0001). Embolic protection devices were used in only 1.7% of procedures in 1997 but deployed in all but 3% of procedures in 2010 (P < .0001). Procedural duration decreased by about 4 minutes (P < .001) over time, while performance of CAS for ipsilateral restenosis after prior CAS increased between the first and last 4 years of the study period (P = .02).

Ongoing Research Influences Practice

According to the authors, the patients enrolled in the ALKK registry are similar to those in other CAS registries. They attribute the shift toward treatment of asymptomatic patients to the 1995 publication in JAMA of the Asymptomatic Carotid Atherosclerosis Study, which showed benefit from endarterectomy in asymptomatic patients with carotid occlusions greater than 60%.

Nonetheless, “the value of CAS in asymptomatic [patients]is still under debate, especially in times of improved medical treatment options,” Dr. Werner and colleagues write, adding that new trials like SPACE-2 “are on their way to clarify this specific topic.”

The “dramatic” uptick in embolic protection can be attributed to many studies suggesting beneficial effects of these devices over the study period, they suggest, but “their value at protecting against periinterventional strokes is still debated.”

Heart failure has never before been documented as an independent predictor of death or stroke in CAS patients, the authors say, although it is known to be a risk factor for periprocedural embolic events during angiography or PCI. Thus, in routine clinical practice, CAS outcomes seem to be dependent not only on patient characteristics like age and procedural factors like operator experience but also on underlying cardiac function.

Disclosure:

• Dr. Werner reports no relevant conflicts of interest.

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