Cath Lab Digest

Abstract
Background. Non-atherosclerotic internal carotid artery (ICA) lesions are uncommon. The incidence of ICA dissections is estimated to be 2.5 to 3 per 100,000, with a 10% annual recurrence rate of thromboembolic. The incidence of fibromuscular dysplasia (FMD), the most common non-traumatic, non-atherosclerotic, non-inflammatory lesion of the ICA is estimated to be 0.02%, with a more benign natural history. For both pathologies, antithrombotic therapy and blood pressure control are initial therapeutic modalities, surgery only being indicated after ischemic events or aneurysmal degeneration. Herein, we report our experience of a combined conventional and endovascular covered stent treatment of these patients under reversed flow and their respective long-term results.

Patients and methods. From February 1999 to June 2005, 13 patients and 16 ICAs were revascularized using a hybrid conventional/endovascular technique. The patients’ age ranged from 30 to 78 years (mean 48 years). All patients have had neurological symptoms. All patients were treated with a covered stent introduced via a cervical approach.

Results. Two patients suffered from a perioperative transient neurological deficit. Duplex revealed ideally patent prosthesis, both patients fully recovered, with no changes visible on repeat CT scans. One patient developed a recurrent laryngeal nerve weakness perioperatively. However, no perioperative strokes or deaths were observed. The follow-up ranged from 1 to 68 months (mean = 43 months). No thromboembolic neurological events, graft occlusions or hemodynamically significant stenoses were seen during the observation period.

Conclusion. Stent grafting of non-atherosclerotic ICA lesions is safe with low perioperative morbidity and good long-term patency.

Introduction
The current incidence of stroke in Europe and the United States is about 200 per 100,000 population per annum.^1,2 Of these, about 20% are due to atherosclerotic internal carotid artery (ICA) lesions.³ For patients with symptomatic high-grade ICA lesions, it has been proven that surgery significantly reduces stroke recurrence, compared to best medical therapy alone.^4,5
Non-atherosclerotic ICA lesions are much more uncommon. The incidence of ICA dissections is estimated to be 2.5 to 3 per 100,000 with a 10% annual recurrence rate of thromboembolic events.^6–8 The incidence of fibromuscular dysplasia (FMD), the most common non-traumatic, non-atherosclerotic, non-inflammatory lesion of the ICA is estimated to be 0.02%⁹ with a more benign natural history.10 For both pathologies, antithrombotic therapy and blood pressure control are initial therapeutic modalities. Only patients with complications (recurrent ischemic events with high grade stenosis, aneurysmal degeneration of the ICA) after at least 6 months of follow-up are considered surgical candidates.¹¹ The reason for this hesitant surgical approach to these ICA pathologies may well be the unfavorable results. Perioperative stroke rates of 10%, peripheral cranial nerve injury rates of 58%, and mortality rates of 2% in surgically managed patients are reported.¹¹

Recently, we reported on endovascular treatment strategies with covered stents in patients with non-atherosclerotic ICA lesions (FMD and primary dissections) with excellent long-term results and low perioperative morbidity and no mortality.^12,13 Herein, we report our experience using a combined conventional and endovascular covered stent treatment in these patients under reversed flow and their respective long-term results.

Patients and Methods
Patient selection. Symptomatic and asymptomatic patients referred to our department with primary dissection or FMD of the ICA were initially screened with duplex sonography of the carotid and vertebral arteries, accompanied by a magnetic resonance angiography. In inconclusive cases, a digital subtraction angiography was performed. In cases of aneurysm formation, a CT scan (computed tomography) was initiated to evaluate maximum diameter and length of the aneurysm. After assessing all patients neurologically, as well as the morphology of the lesions, antiplatelet therapy was commenced or continued.

The indication for operation was given in patients under antiplatelet therapy with recurrently symptomatic high-grade stenosis measured by flow velocities and DSA as well as aneurysm formation and enlargement during follow up.

Patients
From February 1999 to June 2005, 13 patients and 16 ICA were revascularized using a hybrid conventional/endovascular technique (Table 1).

All patients with FMD were female; two patients with dissection were female, four male ages 30–78, with a mean of 48 years). All patients reported had a history of neurological symptoms.