Case Report
An Unusually Benign Course of Extensive Posterior Circulation Occlusion Sudhir Datar, MD,* Giuseppe Lanzino, MD,† and Alejandro A. Rabinstein, MD‡
Background: Acute basilar artery occlusion is associated with poor outcome. In a few cases, occlusion occurs over a period allowing adequate collateral circulation to the posterior fossa. We describe a rare presentation with transient loss of consciousness (LOC) in a patient with extensive occlusion of the posterior circulation. Methods: Case report. Results: We describe a 70-year-old right-handed man with a history significant for atrial fibrillation and dolichoectasia of the basilar artery. Fourteen years ago, he had a small infarction in the pons resulting in right hemiparesis. Magnetic resonance angiogram at that time showed mild intracranial atherosclerosis. He was treated with warfarin for secondary stroke prevention. He presented to our emergency department after a witnessed spell of LOC after a large meal. On regaining consciousness, he had 2 episodes of emesis. Examination revealed only a spastic right hemiparesis from the old stroke in the pons. Cerebral angiogram showed absent flow in the mid and distal basilar arteries, both posterior cerebral arteries, and both posterior communicating arteries with bilateral stenoses of internal carotid arteries. His international normalized ratio in the emergency department was 1.1. He was treated with intravenous heparin and did well. Three months later, he underwent stent treatment of the worsening stenosis (90%) of the right internal carotid artery. Conclusions: Occasionally, collateral circulation has the potential to maintain adequate perfusion to the posterior fossa in severe cases of posterior circulation occlusion and diffuse intracranial atherosclerotic disease. Careful patient selection is essential before planning any endovascular intervention. Key Words: Stroke— basilar artery occlusion—basilar thrombosis—cerebrovascular atherosclerosis. Ó 2015 by National Stroke Association
From the *Department of Neurology, Wake Forest Baptist Health, Winston-Salem, North Carolina; †Department of Neurosurgery, Mayo Clinic, Rochester, Minnesota; and ‡Department of Neurology, Mayo Clinic, Rochester, Minnesota. Received October 8, 2014; revision received November 29, 2014; accepted March 14, 2015. There was no industry, government, or institutional sponsorship or financial interest in this study. S.D. and A.A.R. declare that they have no conflict of interest and G.L. reports the following disclosures: consultant for Edge Therapeutics, Covidien/ev3, and Codman/Johnson and Johnson. Address correspondence to Sudhir Datar, MD, Department of Neurology, Wake Forest Baptist Health, Medical Center Blvd, Winston-Salem, NC 27157. E-mail: [email protected]. 1052-3057/$ - see front matter Ó 2015 by National Stroke Association http://dx.doi.org/10.1016/j.jstrokecerebrovasdis.2015.03.019
Acute basilar artery occlusion (BAO) is associated with high morbidity and mortality. Atherosclerosis and embolism are common causes. The extent of tissue infarction depends on the following: location of occlusion, degree of occlusion (partial or complete), and the degree of collateral circulation. Often BAO is acute; however, sometimes the occlusion occurs after progressive stenosis, allowing for the development of adequate collateral circulation to the posterior fossa. We describe an unusually benign course of extensive basilar and posterior circulation occlusion.
Case Report A 70-year-old right-handed man presented to our emergency department after a witnessed spell of loss of
Journal of Stroke and Cerebrovascular Diseases, Vol. -, No. - (---), 2015: pp e1-e4
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S. DATAR ET AL.
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Figure 1. Cerebral angiogram: right carotid artery (A, B) and left carotid artery (C, D) showing high-grade stenosis at the origin of both internal carotid arteries and the absence of posterior communicating arteries.
consciousness. After a large carbohydrate-rich meal, he passed out while sitting in his chair at the dining table. Before losing consciousness, he reported a vague nonspecific sensation but denied any symptoms such as vertigo, dysarthria, or diplopia. The patient was unable to respond for several minutes and, on regaining consciousness, had 2 episodes of emesis. He had a medical history significant for hypertension, coronary artery disease, hyperlipidemia, paroxysmal atrial fibrillation, and dolichoectasia of the basilar artery. Fourteen years before presentation, he had a small infarction in the pons resulting in right hemiparesis. Turbulence of blood flow in the dolichoectatic region of the basilar artery with a possible small thrombus was thought to be the cause. He was treated with warfarin for secondary stroke prevention. Magnetic resonance angiogram at that time showed mild intracranial atherosclerosis, which showed progression on subsequent angiograms. The last study was performed 3 years before current presentation. Examination in the emergency room only revealed baseline right hemiparesis from the old stroke in the pons but no new deficits. History of vertebrobasilar disease and 2 episodes of emesis prompted evaluation with cerebral angiogram, (Figs 1 and 2) which showed absent flow in the mid and distal basilar arteries, both posterior cerebral arteries, and both posterior communicating arteries. There were 60%-70% stenoses of both
internal carotid arteries. In addition, the angiogram also showed extensive collateral circulation to the posterior fossa through the external carotid, vertebral, posterior inferior cerebellar, and leptomeningeal arteries. His international normalized ratio in the emergency department was 1.1. He was admitted to the neuroscience intensive care unit and was started on intravenous heparin. Electrocardiogram at presentation, telemetry monitoring in the hospital, and later, Holter monitoring did not show any evidence of cardiac arrhythmias. He continued to be at his neurologic baseline. The patient was eventually discharged from the hospital. His antihypertensive medications were adjusted to prevent drop in blood pressure. Two months later, a follow-up angiogram showed progression of the right internal carotid artery stenosis to 90% for which he underwent endovascular stent treatment. He had improvement in the collateral perfusion to the posterior fossa after the stent placement.
Discussion BAO is usually associated with poor outcome.1,2 This case shows that collateral circulation alone can provide sufficient flow to large areas of the brain, thus averting catastrophic ischemia, even in the presence of extensive large-vessel disease. Our patient had complete cessation
BENIGN COURSE OF BAO
e3
Figure 2. Cerebral angiogram: left vertebral artery anteroposterior view (A, B) and lateral view (C, D) showing no flow in the basilar artery or posterior cerebral arteries. Infratentorial structures and the occipital lobes are perfused by multiple leptomeningeal collaterals coming off posterior inferior cerebellar arteries.
of flow through the basilar, posterior communicating, and posterior cerebral arteries, yet small collateral vessels could provide adequate perfusion to the posterior fossa and the occipital lobes. Magnetic resonance or computed tomography perfusion scans would have added to our understanding of the intracranial circulation; however, they were not performed during the hospital admission as they would not have changed the management. The causative factor for the loss of consciousness cannot be established with certainty. Vasovagal hypotension induced by vomiting is a possibility. Blood pressure was measured after the patient regained consciousness and is thus not reliable. Although we did not find any evidence for a cardiac arrhythmia and the history was not suggestive of seizures as the etiology, these possibilities cannot be completely excluded. Small series of patients have been reported in the literature with subacute to chronic occlusion of the vertebrobasilar circulation that had a relatively benign course.3,4 These patients either had a segmental occlusion of the basilar artery and/or a reconstitution of flow through the posterior communicating arteries. Our patient had more extensive disease, which is what makes this case so unique. He had occlusion of the basilar artery without any flow in the posterior communicating arteries or posterior cerebral arteries. In addition, he
had bilateral stenosis of the internal carotid arteries, thus limiting the collateral flow contribution from the anterior circulation. With the availability of newer interventional techniques to treat basilar occlusion, appropriate selection of the patients who would benefit the most is very important. Recanalization of acute BAO in smaller studies has shown improvement in outcome.5 Basilar recanalization has also been attempted in subacute to chronic cases, but with periprocedural complications.4 This case highlights the importance of recognizing that extensive subacute to chronic occlusion of the posterior circulation, occasionally, can cause minimal symptoms if there is adequate collateral circulation. This should be taken into consideration before planning any endovascular intervention, if technically feasible.
Conclusion Occasionally, collateral circulation has the potential to maintain adequate perfusion to the posterior fossa in severe cases of posterior circulation occlusion and diffuse intracranial atherosclerotic disease. Careful patient selection is essential before planning any endovascular intervention.
S. DATAR ET AL.
e4
References 1. Wijdicks EF, Scott JP. Outcome in patients with acute basilar artery occlusion requiring mechanical ventilation. Stroke 1996;27:1301-1303. 2. Schonewille WJ, Algra A, Serena J, et al. Outcome in patients with basilar artery occlusion treated conv entionally. J Neurol Neurosurg Psychiatr 2005;76: 1238-1241.
3. Caplan LR. Occlusion of the vertebral or basilar artery. Follow up analysis of some patients with benign outcome. Stroke 1979;10:277-282. 4. Dashti SR, Park MS, Stiefel MF, et al. Endovascular recanalization of the subacute to chronically occluded basilar artery: initial experience and technical considerations. Neurosurgery 2010;66:825-831. discussion 31–2. 5. Vergouwen MD, Algra A, Pfefferkorn T, et al. Time is brain (stem) in basilar artery occlusion. Stroke 2012;43:3003-3006.
An Unusually Benign Course of Extensive Posterior Circulation Occlusion Sudhir Datar, MD,* Giuseppe Lanzino, MD,† and Alejandro A. Rabinstein, MD‡
Background: Acute basilar artery occlusion is associated with poor outcome. In a few cases, occlusion occurs over a period allowing adequate collateral circulation to the posterior fossa. We describe a rare presentation with transient loss of consciousness (LOC) in a patient with extensive occlusion of the posterior circulation. Methods: Case report. Results: We describe a 70-year-old right-handed man with a history significant for atrial fibrillation and dolichoectasia of the basilar artery. Fourteen years ago, he had a small infarction in the pons resulting in right hemiparesis. Magnetic resonance angiogram at that time showed mild intracranial atherosclerosis. He was treated with warfarin for secondary stroke prevention. He presented to our emergency department after a witnessed spell of LOC after a large meal. On regaining consciousness, he had 2 episodes of emesis. Examination revealed only a spastic right hemiparesis from the old stroke in the pons. Cerebral angiogram showed absent flow in the mid and distal basilar arteries, both posterior cerebral arteries, and both posterior communicating arteries with bilateral stenoses of internal carotid arteries. His international normalized ratio in the emergency department was 1.1. He was treated with intravenous heparin and did well. Three months later, he underwent stent treatment of the worsening stenosis (90%) of the right internal carotid artery. Conclusions: Occasionally, collateral circulation has the potential to maintain adequate perfusion to the posterior fossa in severe cases of posterior circulation occlusion and diffuse intracranial atherosclerotic disease. Careful patient selection is essential before planning any endovascular intervention. Key Words: Stroke— basilar artery occlusion—basilar thrombosis—cerebrovascular atherosclerosis. Ó 2015 by National Stroke Association
From the *Department of Neurology, Wake Forest Baptist Health, Winston-Salem, North Carolina; †Department of Neurosurgery, Mayo Clinic, Rochester, Minnesota; and ‡Department of Neurology, Mayo Clinic, Rochester, Minnesota. Received October 8, 2014; revision received November 29, 2014; accepted March 14, 2015. There was no industry, government, or institutional sponsorship or financial interest in this study. S.D. and A.A.R. declare that they have no conflict of interest and G.L. reports the following disclosures: consultant for Edge Therapeutics, Covidien/ev3, and Codman/Johnson and Johnson. Address correspondence to Sudhir Datar, MD, Department of Neurology, Wake Forest Baptist Health, Medical Center Blvd, Winston-Salem, NC 27157. E-mail: [email protected]. 1052-3057/$ - see front matter Ó 2015 by National Stroke Association http://dx.doi.org/10.1016/j.jstrokecerebrovasdis.2015.03.019
Acute basilar artery occlusion (BAO) is associated with high morbidity and mortality. Atherosclerosis and embolism are common causes. The extent of tissue infarction depends on the following: location of occlusion, degree of occlusion (partial or complete), and the degree of collateral circulation. Often BAO is acute; however, sometimes the occlusion occurs after progressive stenosis, allowing for the development of adequate collateral circulation to the posterior fossa. We describe an unusually benign course of extensive basilar and posterior circulation occlusion.
Case Report A 70-year-old right-handed man presented to our emergency department after a witnessed spell of loss of
Journal of Stroke and Cerebrovascular Diseases, Vol. -, No. - (---), 2015: pp e1-e4
e1
S. DATAR ET AL.
e2
Figure 1. Cerebral angiogram: right carotid artery (A, B) and left carotid artery (C, D) showing high-grade stenosis at the origin of both internal carotid arteries and the absence of posterior communicating arteries.
consciousness. After a large carbohydrate-rich meal, he passed out while sitting in his chair at the dining table. Before losing consciousness, he reported a vague nonspecific sensation but denied any symptoms such as vertigo, dysarthria, or diplopia. The patient was unable to respond for several minutes and, on regaining consciousness, had 2 episodes of emesis. He had a medical history significant for hypertension, coronary artery disease, hyperlipidemia, paroxysmal atrial fibrillation, and dolichoectasia of the basilar artery. Fourteen years before presentation, he had a small infarction in the pons resulting in right hemiparesis. Turbulence of blood flow in the dolichoectatic region of the basilar artery with a possible small thrombus was thought to be the cause. He was treated with warfarin for secondary stroke prevention. Magnetic resonance angiogram at that time showed mild intracranial atherosclerosis, which showed progression on subsequent angiograms. The last study was performed 3 years before current presentation. Examination in the emergency room only revealed baseline right hemiparesis from the old stroke in the pons but no new deficits. History of vertebrobasilar disease and 2 episodes of emesis prompted evaluation with cerebral angiogram, (Figs 1 and 2) which showed absent flow in the mid and distal basilar arteries, both posterior cerebral arteries, and both posterior communicating arteries. There were 60%-70% stenoses of both
internal carotid arteries. In addition, the angiogram also showed extensive collateral circulation to the posterior fossa through the external carotid, vertebral, posterior inferior cerebellar, and leptomeningeal arteries. His international normalized ratio in the emergency department was 1.1. He was admitted to the neuroscience intensive care unit and was started on intravenous heparin. Electrocardiogram at presentation, telemetry monitoring in the hospital, and later, Holter monitoring did not show any evidence of cardiac arrhythmias. He continued to be at his neurologic baseline. The patient was eventually discharged from the hospital. His antihypertensive medications were adjusted to prevent drop in blood pressure. Two months later, a follow-up angiogram showed progression of the right internal carotid artery stenosis to 90% for which he underwent endovascular stent treatment. He had improvement in the collateral perfusion to the posterior fossa after the stent placement.
Discussion BAO is usually associated with poor outcome.1,2 This case shows that collateral circulation alone can provide sufficient flow to large areas of the brain, thus averting catastrophic ischemia, even in the presence of extensive large-vessel disease. Our patient had complete cessation
BENIGN COURSE OF BAO
e3
Figure 2. Cerebral angiogram: left vertebral artery anteroposterior view (A, B) and lateral view (C, D) showing no flow in the basilar artery or posterior cerebral arteries. Infratentorial structures and the occipital lobes are perfused by multiple leptomeningeal collaterals coming off posterior inferior cerebellar arteries.
of flow through the basilar, posterior communicating, and posterior cerebral arteries, yet small collateral vessels could provide adequate perfusion to the posterior fossa and the occipital lobes. Magnetic resonance or computed tomography perfusion scans would have added to our understanding of the intracranial circulation; however, they were not performed during the hospital admission as they would not have changed the management. The causative factor for the loss of consciousness cannot be established with certainty. Vasovagal hypotension induced by vomiting is a possibility. Blood pressure was measured after the patient regained consciousness and is thus not reliable. Although we did not find any evidence for a cardiac arrhythmia and the history was not suggestive of seizures as the etiology, these possibilities cannot be completely excluded. Small series of patients have been reported in the literature with subacute to chronic occlusion of the vertebrobasilar circulation that had a relatively benign course.3,4 These patients either had a segmental occlusion of the basilar artery and/or a reconstitution of flow through the posterior communicating arteries. Our patient had more extensive disease, which is what makes this case so unique. He had occlusion of the basilar artery without any flow in the posterior communicating arteries or posterior cerebral arteries. In addition, he
had bilateral stenosis of the internal carotid arteries, thus limiting the collateral flow contribution from the anterior circulation. With the availability of newer interventional techniques to treat basilar occlusion, appropriate selection of the patients who would benefit the most is very important. Recanalization of acute BAO in smaller studies has shown improvement in outcome.5 Basilar recanalization has also been attempted in subacute to chronic cases, but with periprocedural complications.4 This case highlights the importance of recognizing that extensive subacute to chronic occlusion of the posterior circulation, occasionally, can cause minimal symptoms if there is adequate collateral circulation. This should be taken into consideration before planning any endovascular intervention, if technically feasible.
Conclusion Occasionally, collateral circulation has the potential to maintain adequate perfusion to the posterior fossa in severe cases of posterior circulation occlusion and diffuse intracranial atherosclerotic disease. Careful patient selection is essential before planning any endovascular intervention.
S. DATAR ET AL.
e4
References 1. Wijdicks EF, Scott JP. Outcome in patients with acute basilar artery occlusion requiring mechanical ventilation. Stroke 1996;27:1301-1303. 2. Schonewille WJ, Algra A, Serena J, et al. Outcome in patients with basilar artery occlusion treated conv entionally. J Neurol Neurosurg Psychiatr 2005;76: 1238-1241.
3. Caplan LR. Occlusion of the vertebral or basilar artery. Follow up analysis of some patients with benign outcome. Stroke 1979;10:277-282. 4. Dashti SR, Park MS, Stiefel MF, et al. Endovascular recanalization of the subacute to chronically occluded basilar artery: initial experience and technical considerations. Neurosurgery 2010;66:825-831. discussion 31–2. 5. Vergouwen MD, Algra A, Pfefferkorn T, et al. Time is brain (stem) in basilar artery occlusion. Stroke 2012;43:3003-3006.
