Abstract
We describe a case of a patient who presented with an acute stroke and thrombosed aneurysm of the same vessel. We review the literature on acute stroke management in the setting of an ischemic stroke caused by a thrombosed aneurysm, including intravenous thrombolysis and mechanical thrombectomy. We found that it is unclear whether thrombolysis is safe in these cases. Future case series may be helpful in answering the question.
Keywords: stroke, cerebrovascular disorders, intracranial aneurysm, cerebrovascular disorders, thrombolysis
Case Presentation
A 60-year-old woman presents as a stroke code 25 minutes after the onset of left facial droop and left arm weakness. Her initial National Institutes of Health Stroke Scale (NIHSS) score is 7. The unenhanced computed tomography (CT) scan of the head (Figure 1) shows early ischemic changes only in the right frontal operculum and insula (ASPECTS score 8) as well as a large, hyperdense, spherical, extra-axial lesion in the right Sylvian fissure. The CT angiogram (CTA; Figure 2) shows minimal contrast opacification of this lesion, consistent with a thrombosed aneurysm. There is lack of contrastation of the right Middle Cerebral Artery (MCA) anterior M2 branch, which appears to be arising out of the aneurysm. Computed tomography perfusion (Figure 3) demonstrates prolonged time to peak in the right frontal lobe and opercular regions with reduced cerebral blood flow but preserved cerebral blood volume. Should the clinical team provide intravenous thrombolysis?
Figure 1.
Plain computed tomography (CT) head 1.5 hours after the onset of patient’s symptoms, demonstrating a right Middle Cerebral Artery (MCA) bifurcation aneurysm of high attenuation, in keeping with thrombosis.
Figure 2.
Computed tomography (CT) angiogram 1.5 hours after symptom onset, demonstrating occlusion of the anterior M2 branch of the right Middle Cerebral Artery (MCA) with moderate distal collaterals. The right MCA bifurcation aneurysm does not enhance and is in keeping with thrombosis.
Figure 3.
Computed tomography (CT) perfusion 1.5 hours after symptom onset, demonstrating adequate cerebral brain volume (CBV; A) and Cerebral Blood Flow (CBF) (B), despite increased time to perfusion (TTP; C).
Discussion
Incidental unruptured intracranial aneurysms are not infrequently detected in patients with stroke, with a prevalence reported anywhere between 3.6% and 6.6%.1-3 This is likely because the 2 diseases share similar risk factors, including smoking and hypertension. Unruptured cerebral aneurysms are a recognized but rarely reported cause for acute ischemic stroke.4-8 One study of 3202 patients with stroke found that unruptured aneurysms were the potential cause in only 0.5% of cases.9 Proposed mechanisms of stroke related to unruptured aneurysms include thrombosis with distal embolization, extension of thrombosis into the parent artery, or compression of the parent artery by the aneurysm.9 Aneurysm thrombosis has been hypothesized to be caused by flow stasis within the dome of larger aneurysms.7
Unruptured intracranial aneurysms found incidentally in patients with acute stroke are not associated with an increased risk of intracranial bleeding after thrombolysis.3,10,11 Consequently, the 2018 AHA guidelines suggest that thrombolysis (tPA) is safe in unruptured aneurysms less than 10 mm in diameter, though there is limited evidence to guide acute reperfusion in the case of larger aneurysms, or aneurysms causally related to the acute stroke itself.12 A case series of 3 patients with stroke related to thrombosed aneurysm discussed management of the aneurysm but did not consider thrombolysis or thrombectomy acutely.13 We found one reported case where an acute ischemic stroke of the right MCA (M1 occlusion) was treated with intravenous (IV) thrombolysis, resulting in the rupture of a concealed aneurysm in the parent M1.14 The authors suggested that aneurysms related to the artery affected in stroke may present a higher risk of post-thrombolysis rupture and hemorrhage than do distal aneurysms, though this is not known definitively.
Experience with endovascular thrombectomy in patients with thrombosed intracranial aneurysms causing acute stroke is also limited. One case report detailed the endovascular management of a giant aneurysm of the cavernous right internal carotid artery with stroke due to occlusion of the ipsilateral M1; recanalization was achieved after 1 pass with an aspiration catheter and 2 attempts with stent retrievers.15 Intravenous thrombolysis was not administered in that case. The patient had presented with an initial NIHSS of 12 and had a 90-day modified Rankin Score (mRS) of 2.
Management
Immediately after the CT scan, the patient’s NIHSS improved spontaneously from 12 to 4. The decision was made not to offer IV thrombolysis as the overall risk of treatment was felt to outweigh the likely benefit. Had her deficits worsened, we planned to offer thrombolysis, though only after a thorough discussion of the potential risks (including aneurysm rupture) with the patient or with a legally authorized representative. Given the clinical improvement and distal M2 location, thrombectomy was not considered. Because the symptomatic occluded artery appeared to be arising from the aneurysm, the potential risks of thrombectomy, including device-related perforation of the aneurysm and distal embolization, were felt to be high.
The patient ultimately did very well, with an NIHSS of 2 for facial droop and dysarthria at 24 hours. Her 90-day mRS was 1. Subsequent CTA after discharge (Figure 4) demonstrated partial recanalization of the aneurysm, and therefore, the plan was made for serial imaging and consideration of stent-assisted coiling.
Figure 4.
Computed tomography (CT) angiogram 1 week after presentation, demonstrating complete recanalization of the right superior M2 segment and partial recanalization of the right Middle Cerebral Artery (MCA) bifurcation thrombosed aneurysm.
Footnotes
Authors’ Note: The patient discussed in this manuscript provided written informed consent for its publication.
Declaration of Conflicting Interests: The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding: The authors received no financial support for the research, authorship, and/or publication of this article.
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