Emergent Self-Expanding Stent Placement for Acute Intracranial or Extracranial Internal Carotid Artery Dissection with Significant Hemodynamic Insufficiency

Discussion

ICAD is an important cause of stroke in young or middle-aged patients.^1–3 Clinical manifestations of acute ICAD vary, with local symptoms, cerebral ischemia, or both.³ In acute ICAD presenting with ischemic symptoms, most strokes or transient ischemic attacks are embolic in nature; therefore, they are mostly associated with good outcomes after administration of anticoagulation and/or antiplatelet medications.^5–12 Although stent placement for ICAD is both feasible and safe,¹³ it is reserved for selected patients with ICAD with recurrent embolism refractory to medication, with contraindications for anticoagulation, or with persistent/enlarging pseudoaneurysms.^14–17 Stent placement for ICADs to reverse acute hemodynamic insufficiency or impending infarcts is described in only a few studies.^18,19 Hemodynamic insufficiency due to acute obstruction or critical stenosis caused by dissection plays a key role in stroke progression in only a small number of patients with acute ICAD when combined with a lack of sufficient collateral circulation. In such cases, the patients have complete stroke at initial presentation or present with progressive neurologic deficits.⁴

Kremer et al²⁰ reported a benign clinical course of unilateral ICAD causing severe stenosis or occlusion in 161 patients. However, in that study, 4 patients with permanent and 5 patients with transient severe stenosis or occlusion were excluded because they had undergone either bypass surgery or endovascular therapy for ICAD. Those 9 patients may be similar to those included in this study. Therefore, in the study of Kremer et al, approximately 5.6% (9/161) of patients with acute ICAD required surgical or endovascular intervention at initial presentation. Patients who survive severely stenotic or occlusive ICAD without stroke or progressive neurologic deficits at initial presentation may have sufficient collateral circulation to relevant brain tissue.

Because most severe stenoses and some occlusions eventually recanalize within weeks or months, embolic phenomena may be the only major complications in such patients.^20,21 Therefore, conservative management with anticoagulation or antiplatelet medication may be sufficient, and further intervention may not be required in such patients. However, patients with impending infarcts or progressive neurologic deficits due to significant hemodynamic insufficiency may require early or emergent surgical or endovascular intervention.^4,18,19

In this study, all patients presented with progressive (n = 6) or fluctuating (n = 2) neurologic deficits and revealed markedly decreased perfusion on CT or MR perfusion studies. Catheter angiograms also showed acute obstruction (n = 2) or critical stenosis (n = 6) with a lack of sufficient collateral supply. On the basis of the progression of neurologic deficits and radiographic findings, all patients underwent emergent self-expanding stent placement for correction of acute hemodynamic insufficiency due to intracranial (n = 3) and extracranial (n = 5) ICADs. All patients experienced excellent clinical and angiographic outcomes, with no procedure-related complications.

To the best of our knowledge, only 1 case of intracranial stent placement used to treat intracranially extended cervical ICAD as a part of multiple stent placement has been described in the literature.²² In that report, a self-expanding Neuroform stent was deployed from the intradural supraclinoid to the cavernous segment of the dissection, followed by tandem stent placement of 4 balloon-expandable stents covering the extradural-cavernous-to-cervical segments. Concerning the use of self-expanding stents to treat dissection, Ansari et al²³ reported that the use of self-expanding Neuroform stents was successful for the treatment of 2 cervical ICADs and 7 high cervical or intracranial vertebrobasilar dissections.

In the current study, self-expanding stent placement was used safely and effectively for the treatment of intracranial ICADs and extracranial ICADs. It was also used in 2 obstructive and 6 stenotic ICADs. Our results correspond well with those of previous case series showing that stent placement is safe and effective for acute extracranial ICAD.^14–19 Our results also suggest that this treatment may be safe and effective for intracranial acute ICAD. When stent placement is tried for treating an intradural dissection, one can never be too careful in navigating a guidewire to cross the dissection. Because the intradural arteries have little external elastic lamina, procedural rupture or aggravation of dissection may occur more easily in intradural arterial segments than in the extradural ones. Therefore, the guidewire should be withdrawn and renavigated if any resistance is felt during navigation. Fortunately, in all intradural ICA dissections in this series, the guidewire was easily negotiated through the dissected segment at the initial attempt. However, when difficulty is encountered in passing a guidewire through the dissected segment with any cause, an alternative surgical option, such as bypass surgery, should be considered.

The long-term patency of stented ICAs is a concern. However, in this study, all 6 patients for whom follow-up angiography was available revealed no residual or in-stent stenosis. This result corresponds well with other results reported in the literature.^13,24 Therefore, delayed in-stent restenosis may not be a significant problem when treating ICA dissection by using stent-placement procedures.