Prediction Models After Carotid Revascularization

Study Questions:

What is the external validity/performance of previously published prediction models for short- and long-term outcome after carotid revascularization in patients with symptomatic carotid artery stenosis?

Methods:

The investigators selected all prediction models that used only readily available patient characteristics known before procedure initiation. Follow-up data from 2,184 carotid artery stenting (CAS) and 2,261 carotid endarterectomy (CEA) patients from four randomized trials were used to validate 23 short-term outcome models to estimate stroke or death risk ≤30 days after the procedure and the original outcome measure for which the model was developed. Trials included were EVA-3S (Endarterectomy Versus Angioplasty in Patients With Symptomatic Severe Carotid Stenosis], SPACE (Stent-Protected Angioplasty Versus Carotid Endarterectomy], ICSS (International Carotid Stenting Study], and CREST (Carotid Revascularization Endarterectomy Versus Stenting Trial]. Additionally, the authors validated seven long-term outcome models for the original outcome measure. Predictive performance of the models was assessed with C statistics and calibration plots.

Results:

Stroke or death ≤30 days after the procedure occurred in 158 (7.2%) patients after CAS and in 84 (3.7%) patients after CEA. Most models for short-term outcome after CAS (n = 4) or CEA (n = 19) had poor discriminative performance (C statistics ranging from 0.49–0.64) and poor calibration, with small absolute risk differences between the lowest and highest risk groups and overestimation of risk in the highest risk groups. Long-term outcome models (n = 7) had a slightly better performance, with C statistics ranging from 0.59–0.67 and reasonable calibration.

Conclusions:

The authors concluded that current models did not reliably predict outcome after carotid revascularization in a trial population of patients with symptomatic carotid stenosis.

Perspective:

This study assessed predictive performance of 30 existing prediction models for short- and long-term outcome after carotid revascularization in a large population of patients with symptomatic internal carotid artery stenosis, and reported that most prediction models for short-term outcome after CAS or CEA had poor ability to discriminate between patients who will and will not get an event. Overall, these prediction models cannot predict which patients have a higher long-term stroke risk despite CAS or CEA, and therefore, are not specific for outcome prediction after carotid revascularization. These data suggest that we need to develop newer prediction models, preferably in a more heterogeneous study population with sufficient information on predictors and outcomes to accurately estimate risks after CAS or CEA in individual patients with carotid stenosis.

Clinical Topics: Cardiac Surgery, Invasive Cardiovascular Angiography and Intervention, Prevention, Vascular Medicine, Aortic Surgery, Cardiac Surgery and Arrhythmias, Interventions and Vascular Medicine

Keywords: Angioplasty, Carotid Stenosis, Endarterectomy, Carotid, Myocardial Revascularization, Outcome Assessment (Health Care), Risk Assessment, Secondary Prevention, Stents, Stroke, Vascular Diseases


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