Risk factor profile and anatomic features of previously asymptomatic patients presenting with carotid-related stroke

Abstract

Objective: Although carotid atherosclerotic-mediated stroke remains a major cause of morbidity and mortality, some have suggested intervention in carotid stenosis should be limited to symptomatic patients given the advances in medical therapy. The present study was conducted to assess the atherosclerotic risk factor profiles, anatomic features, and clinical outcomes of previously asymptomatic patients admitted with stroke of carotid etiology.

Methods: We reviewed the data from 3382 patients admitted to a tertiary referral center with an ischemic stroke during 2005 to 2015. We focused on patients admitted with a radiographically confirmed infarct ipsilateral to a documented carotid artery stenosis ≥50%, with the admitting neurology team adjudicating the stroke etiology as carotid related. Patients were excluded if they had had a previous transient ischemic attack, previous infarct ipsilateral to any carotid lesion, or previous carotid revascularization, intracranial hemorrhage, or malignancy. Patient demographic data, medical treatments before stroke, stroke admission carotid imaging, and stroke treatments and outcomes were assessed.

Results: A total of 219 carotid stroke patients (7% of all strokes) were identified, of whom 61% were white and 66% were men, with a mean age of 68 ± 12 years. Hypertension (79%) and smoking (33% current; 29% former) were predominant risk factors. On admission, 50% were receiving antiplatelet therapy (aspirin, n = 92 [41%]; clopidogrel, n = 9 [4%]; dual therapy, n = 11 [5%]) and 55% were receiving lipid-lowering agents (statin, n = 115 [53%]; other, n = 6 [2%]); 77 patients (35%) were receiving both antiplatelet and lipid-lowering therapy. Of the 219 patients, 156 (71%) presented with a moderate or severe stroke (National Institutes of Health stroke scale ≥5 at admission), 54 (25%) received lytic therapy, 96 (43%) presented with an occluded ipsilateral internal carotid artery, and 117 (53%) ultimately underwent carotid revascularization at a median of 4 days. Individuals receiving both antiplatelet and lipid-lowering therapy were significantly less likely to experience a moderate or severe stroke (44% vs 78%; P = .006).

Conclusions: Internal carotid artery occlusion is the culprit lesion in 43% of carotid-related strokes in those without previous symptoms. Previously asymptomatic patients not receiving combined antiplatelet and lipid-lowering medical therapy presenting with carotid-related stroke are significantly more likely to experience a severe, debilitating stroke. However, those receiving appropriate risk-reduction medical therapy are still at risk of carotid-mediated stroke. These results suggest medical therapy alone is unlikely to be sufficient stroke prevention for patients with significant carotid stenosis.

Keywords: Anatomy; Carotid; Ischemic; Risk; Stroke.