Carotid ultrasound imaging in a patient with acute ischemic stroke and aortic dissection: a lesson for the management of ischemic stroke?

Authors


  • Conflict of interest: N. Morelli, M. Mancuso, E. Rota, P. Immovilli, M. Spallazzi, G. Rocca, E. Michieletti, and D. Guidetti report no disclosures.
  • Author contributions: study concepts, N. Morelli; study design, N. Morelli, P. Immovilli; literature research, M. Spallazzi; clinical studies, M. Spallazzi, G. Rocca; data analysis/interpretation, N. Morelli; manuscript preparation and definition of intellectual content, N. Morelli; manuscript editing, N. Morelli.; manuscript revision/review, E. Rota, E. Michieletti, M. Mancuso and D. Guidetti, all author's approval manuscript final version. No financial support was received for this project.

Dear editor, aortic dissection presenting as an acute ischemic stroke represents an important challenge to neurologists, especially in pain-free dissection (5– 15% of the cases) [1]. In this context, thrombolysis is a life-threatening approach for acute ischemic stroke patients.

A 60-year-old smoker female, history of hypertension, no other vascular risk factor, was admitted to emergency department (ED) for sudden left hemiparesis (National Institute of Health Stroke Scale, NIHSS 9) appeared 90 mins before, with a normal brain computed tomography (CT). The patient was fully oriented, without pain or any other complaints. Her blood pressure (BP) was 130/70 mmHg, chest X-ray, electrocardiogram (EKG), and cardiac evaluation were normal. Blood tests were also normal. Therefore, the patient was considered eligible for intravenous recombinant tissue plasminogen activator (rt-PA), which was started 125 mins after the onset of the stroke. The patient's neurological picture improved within 40 mins (NIHSS 3). Four-hours later, her skin became pale and sweaty. Physical examination detected asymmetry of peripheral pulses at the upper extremities, BP dropped to 80/60 in right arm and 110/60 on the left side without any worsening of the neurologic picture or other associated symptoms. An urgent carotid duplex ultrasonography was requested. Extracranial sonography on the longitudinal and axial plane in the right common carotid artery revealed double lumen with moving membrane, attributable to dissection (supporting information Movies S1 and S2). Different flow velocities on pulsed wave analysis were detected within the true and the false lumen with a to-and-fro spectral profile in the latter. The CT angiography of the aorta documented DeBakey type I aortic dissection, which extended to the common iliac arteries and involved the right common carotid artery. An emergency surgical replacement of the ascending aorta was therefore performed 12 h after the onset of the first symptoms. She was discharged 42 days later with left facial and mild upper limb paresis (NIHSS 2). At 12 months, the patient is still independent in her daily life activities.

Aortic dissection presenting as an ischemic stroke represents an important challenge to emergency departments. Neurological symptoms at the onset of aortic dissection are not only frequent (17–40%), but often dramatic and may mask underlying conditions [1]. This is particularly true in the presence of pain-free dissections with predominant neurological symptoms, where diagnosis of aortic dissection can be difficult, delayed, or missed. In case of aortic dissection, massive use of antiplatelet or anticoagulant drugs is contraindicated [2].

Considering that early intravenous thrombolytic therapy in acute ischemic stroke is becoming a common practice in the neurological field, misdiagnosis could be fatal in the case of aortic dissection [1, 3]. However, current guidelines do not state specifically whether aortic dissection is a contraindication to rt-PA administration [2]. The most common mechanism of brain ischemic damage is mechanical obstruction of the common carotid artery due to the dissection. Complete occlusion might be resistant to rt-PA, which is not effective for mechanical occlusion. Therefore, rt-PA for ischemic stroke secondary to aortic dissection might be efficacious only in a minority of patients with thromboembolic mechanism.

Moreover, there are reports of suspected myocardial infarction inadvertently treated with thrombolysis, complicated by extension of the dissection into the pericardium, leading to cardiac tamponade and death [3]. rt-PA must be administrated within a very brief time window; therefore, it is crucial that major contraindications to this therapy must be detected in a very short time.

Whereas rt-PA therapy has been successfully reported in patients with isolated internal carotid artery dissection, the risk of thrombolytic therapy seems to be much higher when dissection occurs in the aorta [4]. Because aortic dissection is a very rare cause of ischemic stroke [1], the acute screening for this entity has to be questioned. A timely chest X-ray should be considered as part of acute ischemic patients' protocols, with special attention to the presence of enlarged mediastinal shadow. Moreover, the presence of hypotension, reduced peripheral pulses, aortic regurgitation murmurs should be always searched before rt-PA therapy.

A common or internal carotid artery dissection has been associated in more than 40% of aortic dissection [5]. These vessels can be easily investigated by sonography, which should be regarded as a helpful, complementary tool for the current diagnostic workup. The sonographic findings might influence the short-term management of a suspected aortic dissection in any patient entering the emergency department.

In conclusion, ultrasonography may be a useful tool in diagnosing aortic dissection before rt-PA infusion in acute ischemic stroke patients. Intravenous rt-PA might not be indicated in most patients with acute ischemic stroke secondary to aortic and carotid dissection, even though some cases [5, 6], including our case, may have a good outcome.

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