Alan Z Segal's research while affiliated with Weill Cornell Medical College and other places

Publications (78)

Article
Objective: To evaluate whether patients discharged to home after an emergency department (ED) visit for headache face a heightened short-term risk of stroke. Background: Stroke hospitalizations that occur soon after ED visits for headache complaints may reflect diagnostic error. Methods: We conducted a retrospective cohort study using statewid...
Poster
Introduction: Reductions in hospital visits for stroke have been seen during the COVID-19 pandemic, partly reflecting perceived risks of in-hospital care. We recently implemented an evidence-based protocol for outpatient rapid evaluation of transient and minor, non-disabling stroke symptoms for patients seeking care 24 hours after symptom onset. We...
Poster
Background: Cervical artery dissection (CAD) often affects young, otherwise healthy people. Few data exist on whether patients with CAD face an increased vulnerability to aortic dissection. Herein we tested the hypothesis that CAD is associated with an increased risk of aortic dissection. Methods: We performed a retrospective cohort study using sta...
Article
Coronavirus disease (COVID-19) has a number of emerging neurological manifestations in addition to pneumonia and respiratory distress. In what follows, we describe a case of a previously healthy young man with severe COVID-19 who subsequently developed an acute flaccid paralysis. Work up revealed a lesion in his cervical spinal cord concerning for...
Poster
Introduction: Arterial dissections often have no known identifiable risk factor. Whether infection/inflammation may play a role in the development of arterial dissection is uncertain. Hypothesis: Influenza-like illness (ILI) is associated with a heightened risk of arterial dissection. Methods: We performed a case-crossover analysis using administra...
Article
Cerebrovascular complications among critically ill patients with COVID-19 have yet to be fully characterized. In this retrospective case series from a single academic tertiary care referral center in New York City, we present 12 patients with ischemic or hemorrhagic strokes that were found on imaging after a period of prolonged sedation in the sett...
Article
Full-text available
We report a case of central retinal artery occlusion (CRAO) leading to unilateral blindness occurring in a moyamoya patient 30 years after successful pial synangiosis when she was 6 years old. Imaging studies at the time of the CRAO revealed total occlusion of the ipsilateral cervical and intracranial internal carotid artery, a vessel shown to be p...
Article
Importance It is uncertain whether coronavirus disease 2019 (COVID-19) is associated with a higher risk of ischemic stroke than would be expected from a viral respiratory infection. Objective To compare the rate of ischemic stroke between patients with COVID-19 and patients with influenza, a respiratory viral illness previously associated with str...
Article
Objective To report four patients with coronavirus disease 2019 (COVID-19) who developed posterior reversible encephalopathy syndrome (PRES). Methods Patient data was abstracted from medical records at Weill Cornell Medical Center. Results Four patients with SARS-CoV-2 infection and PRES were identified. The patients' ages ranged from 64 to 74 ye...
Article
We report a rare case of a cilioretinal artery occlusion in a young patient with a known history of hereditary spherocytosis statuspost-splenectomy who was otherwise healthy. We believe that his hematologic condition and history of splenectomy caused his clinical picture, and encourage the clinical consideration of this rare diagnosis once all othe...
Chapter
The hypercoagulable state associated with cancer, known since the descriptions of Trousseau in the nineteenth century, has become a well-recognized cause of venous thromboembolism. It has only more recently become apparent that cancer increases the risk of arterial thromboembolism as well. In patients with cancer, cerebrovascular disease is the sec...
Preprint
Full-text available
Importance: Case series without control groups suggest that Covid-19 may cause ischemic stroke, but whether Covid-19 is associated with a higher risk of ischemic stroke than would be expected from a viral respiratory infection is uncertain. Objective: To compare the rate of ischemic stroke between patients with Covid-19 and patients with influenza,...
Article
Introduction: Intravenous thrombolytic therapy with recombinant tissue type plasminogen activator (IV-tPA) is the first-line treatment option for acute ischemic stroke (AIS). The tPA exclusion criteria, defined decades ago, require updates as new technologies emerge. Transcatheter aortic valve replacement (TAVR), which has begun to replace open su...
Article
Background and Purpose We sought to determine the proportion of patients with ischemic stroke evaluated by vascular neurologists in the United States. Methods Using 2009 to 2015 claims from a 5% nationally representative sample of Medicare beneficiaries, we identified patients ≥65 years of age who were hospitalized for ischemic stroke. We ascertai...
Article
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Background: The primary objective of this study was to identify the specific predictors of early and late stroke in patients after open heart surgery. Secondary outcomes included (a) risk factors for perioperative stroke, (b) anatomic location of stroke according to time of presentation, and (c) the impact of stroke on operative mortality. Method...
Article
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Purpose of review This review aims to support obstructive sleep apnea (OSA) as a risk factor for ischemic stroke, review treatment strategies for OSA, provide a comprehensive review of clinical data on OSA treatment and ischemic stroke risk, and to critically assess if treatment of OSA decreases the risk of ischemic stroke and if treatment improves...
Article
Objective: The current understanding of the utility of blood-brain barrier permeability (BBBP) evaluation with extended-pass perfusion CT in the clinical setting is limited. We assessed whether BBBP parameters evaluated with perfusion CT correlate with unfavorable clinical outcomes in patients with aneurysmal subarachnoid hemorrhage (SAH). Materi...
Article
Introduction: Stroke is a frequent complication of infective endocarditis, but there are few data and guidelines to inform appropriate neurological evaluation and imaging in this setting. We sought to determine how often patients with endocarditis undergo neuroimaging and evaluation by a neurologist. Methods: Using claims between 2009-2015 from a 5...
Article
Introduction: Given recent advances in diagnostic and therapeutic tools, delivery of stroke care has become more complex. We sought to investigate what proportion of patients with stroke are evaluated by neurologists, and specifically by vascular neurologists. Methods: Using 2008-2015 claims data from a 5% nationally representative sample of Medica...
Article
Background: Growing evidence suggests that obstructive sleep apnea (OSA) is associated with an increased risk of stroke and adverse cardiovascular outcomes; however, there are limited data that treating OSA with positive airway pressure (PAP) devices significantly decreases this risk. We therefore examined the association between PAP therapy and th...
Article
Background and purpose: CT angiography and perfusion imaging is an important prognostic tool in the management of patients with aneurysmal subarachnoid hemorrhage. The purpose of this study was to perform a cost-effectiveness analysis of advanced imaging in patients with SAH, incorporating the risks of radiation exposure from CT angiography and CT...
Article
Protein Z (PZ) is a vitamin K-dependent plasma protein that exhibits both pro- and anticoagulant properties. Both low and high PZ levels have been linked to ischaemic stroke. Although PZ-lowering gene variants have been found to be less common in ischaemic stroke, the relationship remains unclear. We investigated PZ levels and PROZ variants in a mu...
Article
Background and aims: Circulating lipoprotein (a) [Lp(a)] level relates inversely to apolipoprotein (a) [apo(a)] size. Both smaller apo(a) isoforms and higher Lp(a) levels have been linked to coronary heart disease and stroke, but their independent contributions are less well defined. We examined the role of Lp(a) in younger adults with cryptogenic...
Article
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Background and purpose: Blood-brain barrier permeability is not routinely evaluated in the clinical setting. Global cerebral edema occurs after SAH and is associated with BBB disruption. Detection of global cerebral edema using current imaging techniques is challenging. Our purpose was to apply blood-brain barrier permeability imaging in patients...
Article
Postoperative seizure (PS) is an infrequent, yet distressing, complication after cardiac surgery. We wished to determine the prognostic significance of these complicated neurologic events. The Weill Cornell Medical College Department of Cardiothoracic Surgery database and the New York State Department of Health Database were reviewed to identify al...
Article
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Patients with SAH are at increased risk of delayed infarction. Early detection and treatment of delayed infarction remain challenging. We assessed blood-brain barrier permeability, measured as permeability surface area product, by using CTP in patients with SAH with delayed infarction. We performed a retrospective study of patients with SAH with de...
Article
Mechanical ventilation is frequently performed in patients with ischemic stroke (IS), intracerebral hemorrhage (ICH), and subarachnoid hemorrhage (SAH). In this study, we used statewide administrative claims data to examine the rates of use, associated conditions, and in-hospital mortality rates for mechanically ventilated stroke patients. We used...
Article
Full-text available
Delayed cerebral ischemia and vasospasm are significant complications following SAH leading to cerebral infarction, functional disability, and death. In recent years, CTA and CTP have been used to increase the detection of delayed cerebral ischemia and vasospasm. Our aim was to perform comparative-effectiveness and cost-effectiveness analyses evalu...
Article
Full-text available
Cavernous sinus cavernous hemangiomas in pregnancy are extremely rare lesions. The precise management of these lesions remains unknown. The authors present a case of a cavernous hemangioma in pregnancy, centered within the cavernous sinus that underwent postpartum involution without surgical intervention. A 34-year-old pregnant patient (gravida 1,...
Article
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Aneurysmal subarachnoid hemorrhage is associated with high morbidity and mortality, with delayed neurologic deficits from delayed cerebral ischemia contributing to a large portion of the adverse outcomes in this patient population. There is currently no consensus reference standard for establishing the diagnosis of delayed cerebral ischemia either...
Article
Background and purpose: In recent years CTP has been used as a complementary diagnostic tool in the evaluation of delayed cerebral ischemia and vasospasm. Our aim was to determine the test characteristics of CTP for detecting delayed cerebral ischemia and vasospasm in SAH, and then to apply Bayesian analysis to identify subgroups for its appropria...
Article
Sleep spindles have been suggested as surrogates of thalamo-cortical activity. Internal frequency modulation within a spindle's time frame has been demonstrated in healthy subjects, showing that spindles tend to decelerate their frequency before termination. We investigated internal frequency modulation of slow and fast spindles according to Obstru...
Article
Impairments in cerebrovascular reserve (CVR) have been variably associated with increased risk of ischemic events and may stratify stroke risk in patients with high-grade internal carotid artery stenosis or occlusion. The purpose of this study is to perform a systematic review and meta-analysis to summarize the association of CVR impairment and str...
Article
Background and purpose: DCI is a serious complication following aneurysmal SAH and remains a leading cause of morbidity and mortality. Our aim was to evaluate CTP in aneurysmal SAH by using outcome measures of DCI. Materials and methods: This was a retrospective study of consecutive patients with SAH enrolled in a prospective institutional revie...
Article
The purpose is to perform outcomes-based assessment of a new reference standard for delayed cerebral ischemia (DCI) related to vasospasm. Retrospective study was performed with consecutive aneurysmal subarachnoid hemorrhage (A-SAH) patients between January 2002 and May 2009. A new reference standard for DCI was applied to the study population incor...
Article
DCI is a serious complication following aneurysmal SAH leading to permanent neurologic deficits, infarction, and death. Our aim was to prospectively evaluate the diagnostic accuracy of CTP and to determine a quantitative threshold for DCI in aneurysmal SAH. Patients with SAH were prospectively enrolled in a protocol approved by the institutional re...
Article
To analyze the risk factors, presentation, etiologies, and outcomes of adult cancer patients with intracranial hemorrhage (IH). We analyzed 208 patients retrospectively with the diagnosis of IH from the Memorial Sloan-Kettering neurology database from January 2000 through December 2007. Charts were examined for clinical and radiographic data. Survi...
Article
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The characterization of delayed cerebral ischemia (DCI) and vasospasm (VSP) after aneurysmal subarachnoid hemorrhage (aSAH) has evolved with the recognition of independent impacts of clinical neurological deficits and infarctions on outcome, even in the absence of narrowed vessel (NV). There is inter-and intra-RCT inconsistency in semantics and spe...
Article
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Patient-centered care has become a primary focus in clinical practice. In developing practice guidelines for clinical care, the patients' perspective is an important component. Patients' preferences are represented in a decision analytic model as quality-of-life weights for different health states associated with the aneurysmal subarachnoid hemorrh...
Article
Flawed observational studies find weak associations between high cholesterol and ischemic stroke, and low cholesterol and hemorrhagic stroke. Low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and triglycerides each appear to have individual effects on stroke risk and type. Statins decrease the risk of cerebral infarction in...
Article
Cardioaortic brain embolism is a potentially devastating condition that presents frequent diagnostic and therapeutic challenges. In this report, we review key aspects of the etiology, clinical presentation, diagnosis, prognosis, and treatment of cardiogenic and aortogenic stroke. Emphasis is on advances in diagnostic imaging capabilities and on rec...
Article
Cancer patients are hypercoagulable through a variety of mechanisms and are at significant risk for ischemic stroke. Though usually occurring in the later stages of neoplastic disease, stroke can rarely be the first manifestation of an occult malignancy. We report a 46-year-old woman who presented with multiple cerebral infarctions in numerous vasc...
Article
The objective of this randomized trial was to compare the efficacy of two strategies of hemodynamic management during cardiopulmonary bypass (CPB) on morbidity, mortality, cognitive complications and deterioration in functional status. Patients scheduled to undergo primary elective CABG were eligible. In one group, mean arterial pressure target dur...
Article
Mitral annular calcium (MAC) has been shown to be an independent predictor of stroke, but the basis for this association remains incompletely defined. This study was conducted to investigate the extent to which aortogenic embolism may mediate the MAC-stroke relation. In a cross-sectional study of patients referred for transesophageal echocardiograp...
Article
Cerebrovascular events occur frequently in patients who succumb to cancer, and nonbacterial thrombotic endocarditis (NBTE) is a frequent postmortem finding in these patients. Despite the excellent diagnostic accuracy of transesophageal echocardiography (TEE) for cardiac sources of cerebral embolism, however, the prevalence of NBTE and other cardioe...
Article
Despite the documented association between apolipoprotein E genotype and cerebral amyloid angiopathy (CAA), a substantial proportion of CAA-related hemorrhages occur in patients without known risks for this disorder. Two other factors implicated in the pathogenesis of CAA are the amyloid-β peptide (preferentially deposited in vessels as a 40-amino...
Article
Neurologic toxicity is an infrequently reported and under-recognized consequence of amiodarone, symptoms of which may include tremor, peripheral sensorimotor neuropathy, proximal weakness, and ataxia. The investigators report the rapid and complete remission of 4 months of progressively debilitating ataxia with the discontinuation of small-dose ami...
Article
Internal carotid artery (ICA) dissection remains a major cause of stroke in the young. Although systemic anticoagulation and antiplatelet therapy allow healing of the dissection in most patients, medical treatment can fail or be contraindicated. In selected cases of carotid dissections, the use of endovascular stent-assisted angioplasty has been re...
Article
Cerebrovascular disease is common in cancer patients and often arises from mechanisms unique to malignancy. Direct tumor effects include intratumoral hemorrhage, arterial and venous sinus invasion by tumor mass or leptomeningeal infiltrates, and tumor emboli. Complications of chemotherapy, radiation therapy, and hematopoietic stem-cell transplantio...
Article
Mechanical embolectomy in acute ischemic stroke employs the use of novel endovascular devices to revascularize occluded intracerebral arteries. Devices like the Merci Retiever and other endovascular snares, laser thrombectomy and rheolytic/obliterative microcatheters, intracranial balloon angioplasty and stenting, and intra-arterial and transcrania...
Article
To report the result of the Mechanical Embolus Removal in Cerebral Ischemia (MERCI) 1 study, a phase 1 trial to evaluate the safety and efficacy of mechanical embolectomy in the cerebral vasculature. MERCI 1 enrolled 30 patients in 7 US centers. Main inclusion criteria were: National Institutes of Health Stroke Scale score (NIHSS) > or =10; treatme...
Article
To assess the incidence and type of strokes in patients with cancer at Memorial Sloan-Kettering Cancer Center. Retrospective review of all ischemic strokes diagnosed by a neurologist and confirmed by neuroimaging between February 1997 and April 2001 was conducted. Age, gender, cancer diagnosis and stage, and vascular risk factors were recorded. NIH...
Article
A 61-year-old man presenting with transient global aphasia and chronic major depression was found to have a giant high flow dural arteriovenous fistula of the superior sagittal sinus. EEG and SPECT scan showed left frontoparietal dysfunction. This resolved after fistula embolization, as did the patient's neuropsychiatric complaints.
Article
Full-text available
To the Editor: Castellanos et al1 reported increased matrix metalloproteinase (MMP)-9 plasma levels to be an independent risk factor for hemorrhagic transformation in all stroke subtypes. Plasma levels of MMP-9 in patients without hemorrhage were not significantly different from controls, suggesting that MMP-9 does not play an important role in ea...
Article
The risk of stroke after a transient ischemic attack (TIA) is high. Appropriately directed therapies may reduce this risk. However, sensitive means of detecting the presence of subtle neuronal ischemia are lacking. We investigated the potential use of quantitative diffusion-weighted (DW) MR imaging in the detection of deficits produced by transient...
Article
In CT angiographic and perfusion imaging (CTA/CTP), rapid CT scanning is performed during the brief steady state administration of a contrast bolus, creating both vascular phase images of the major intracranial vessels and perfused blood volume-weighted parenchymal phase images of the entire brain. We assessed the added clinical value of the data p...
Article
The goal of this study was to evaluate the utility of perfusion-weighted CT (PWCT) in predicting final infarct volume and clinical outcome in patients with acute middle cerebral artery (MCA) stroke. Twenty-two consecutive patients with MCA stem occlusion who underwent intra-arterial thrombolysis within 6 hours of stroke onset had noncontrast CT and...
Article
To investigate the causes of fever in subarachnoid hemorrhage (SAH) and examine its relationship to outcome. Fever adversely affects outcome in stroke. Patients with SAH are at risk for cerebral ischemia due to vasospasm (VSP). In these patients, fever may be both caused by, and potentiate, VSP-mediated brain injury. The authors prospectively studi...
Article
The aim of this pilot study was to determine whether the use of induced hypertension in acute stroke is feasible and associated with neurologic improvement. Phenylephrine was used to raise the systolic blood pressure in patients with acute stroke by 20%, not to exceed 200 mmHG: Of 13 patients treated, 7 improved by 2 points on the NIH Stroke SCALE:...
Article
Objective: To investigate the causes of fever in subarachnoid hemorrhage (SAH) and examine its relationship to outcome. Background: Fever adversely affects outcome in stroke. Patients with SAH are at risk for cerebral ischemia due to vasospasm (VSP). In these patients, fever may he both caused by, and potentiate, VSP-mediated brain injury. Methods:...
Article
The authors aimed to delineate the risk factors and radiologic pattern of stroke complicating cardiac catheterization. Twenty-two cases were matched with three control subjects. Stroke was significantly associated with severity of coronary artery disease and length of fluoroscopy time (OR 1.96 and 1.65). The use of MRI with diffusion weighting allo...
Article
Full-text available
52 Objective: The diagnosis of ischemic stroke subtype is difficult in the emergency setting when based only upon a non-contrast CT scan and clinical findings. Accurate diagnosis may be important because prognosis depends upon the size and location of the infarct and emergency therapeutic decisions rest upon attempts to improve prognosis. Diffusion...
Article
Despite the documented association between apolipoprotein E genotype and cerebral amyloid angiopathy (CAA), a substantial proportion of CAA-related hemorrhages occur in patients without known risks for this disorder. Two other factors implicated in the pathogenesis of CAA are the amyloid-beta peptide (preferentially deposited in vessels as a 40-ami...
Article
Full-text available
Recurrent lobar intracerebral hemorrhage is the hallmark of cerebral amyloid angiopathy. The factors that predispose patients to early recurrence of lobar hemorrhage are unknown. One candidate is the apolipoprotein E gene, since both the epsilon2 and the epsilon4 alleles of apolipoprotein E appear to be associated with the severity of amyloid angio...
Article
We performed a case-control study to assess the relationship between primary intracerebral hemorrhage (ICH) and low serum cholesterol. Prospectively recruited, fully evaluated patients with ICH were compared to two independent control groups, one based in a primary care practice and one population-based. Low cholesterol was defined by the sex-speci...
Article
Hemorrhage related to cerebral amyloid angiopathy (CAA) appears to occur through a multistep pathway that includes deposition of beta-amyloid in cerebral vessels and specific vasculopathic changes in the amyloid-laden vessels, such as cracking of the vessel wall. Recent reports suggest a positive association between CAA-related hemorrhage and both...

Citations

... In a large heterogenous cohort, Witsch et al. reported that CeAD was associated with a four-fold increased risk of subsequent aortic dissection. Future studies need to investigate which CeAD patients are at increased risk for aortic dissection in order to provide preventive screening, genetic counselling and aggressive cardiovascular risk factor control [26]. ...
... In accordance with our patient, the cases of Sampogna et al. [4] and Amalia et al. [7] comprise ischemia involving the lower thoracic spinal cord. Conversely, cervical spinal cord infarction was reported by Bax et al. and Kahan et al. [5,6], whereas Eissa et al. [3] describe a case of vertebral artery thrombosis with concomitant posterior circulation stroke. In the case of Bax et al. [6], spinal cord ischemia preceded the initiation of COVID infection symptoms, in contrast to the remainder studies, where spinal stroke occurred 1 to 3 weeks after the flu-like symptoms [3][4][5]7]. ...
... Moreover, in a recent meta-analysis, patients with severe COVID-19 had a five-fold increase in the risk of stroke (OR = 5.1, 95% CI: 2.72-9.54) [163], and these data could even be underestimated, in particular in sedated and mechanically ventilated patients [154,164]. Compared to non-COVID-19 patients, patients with CO-VID-19 suffering a stroke presented in the emergency room in delay were younger, more likely male, with a more severe clinical presentation compared to controls, higher NIHSS on admission and frequently with LVO [165], significantly less likely to receive acute revascularization treatments [166], with longer hospitalization duration, poorer clinical and neuroradiologic outcomes, higher rates of early re-occlusion, and an increased mortality [148,[167][168][169][170]. The etiology of AIS in COVID-19 patients has been more often cardioembolic or cryptogenic [163,169]; this last could be attributed to an incomplete diagnostic path due to the limited availability of resources in the under-pressure healthcare system. ...
... Several pathophysiological mechanisms triggered by the coronavirus could explain the endothelial dysfunction associated with PRES. The latter could be triggered by cytokine release with the development of an exaggerated systemic response, as well as by direct viral injury by SARS-CoV-2, since the nervous system endothelium expresses ACE receptors 3,7 . ...
... Infection with SARS-CoV-2 is associated with neurological and cerebrovascular complications. 1,2,3 Additionally, several studies found greater stroke severity in patients with ischemic stroke (IS) and concurrent SARS-CoV-2 infection. 4,5,6,7,8,9 Most of these data come from the early COVID-19 pandemic period when there was rapid and substantial disruption of stroke care delivery and resources. ...
... As reported by the WHO, the risk of ischemic stroke amongst COVID-19 patients is ~5%, which is higher than the risk for hemorrhagic stroke [53]. The prevalence of stroke in COVID-19 patients is estimated to be seven times higher than in patients admitted to hospital with influenza, even after taking into consideration the severity of the disease [54]. Out of 43 patients who had died in intensive care units, general wards or nursing homes from COVID-19 related pneumonia or sepsis, six individuals (14%) had acute ischemic brain lesions [55]. ...
... Given that TAVR is a less invasive approach to open surgical AVR, the use of thrombolysis may be considered, although the supporting literature is limited to only case reports. [30][31][32] Randomized controlled trials are warranted to investigate outcomes of thrombolysis and endovascular thrombectomy for AIS after TAVR. ...
... [9,10] CPAP is used as therapeutic as well as diagnostic for OSA patient. [11][12][13][14] CPAP works to keep the airway open and therefore prevents airway collapse, improves quality of sleep, reduces mortality rate, reduces high blood pressure, and reduces sympathetic tone during daytime and nighttime. [15][16][17][18][19][20] OA improves upper airway configuration and prevents airway collapse through alteration in positions of jaw and tongue. ...
... Perioperative stroke comprised 2 distinct phenomena: early/intraoperative and late/delayed/postoperative stroke. Early stroke is typically defined as a stroke that is identified when patients first wake from anesthesia or after they are extubated [9]. Patients with late or delayed strokes are defined as those who are normal neurologically when emerging from anesthesia, but later develop symptoms either during the hospital course or after discharge but within 30 days post-surgery. ...
... Neuroinflammatory recruitment to the CSF space appears to be important for the relationship between systemic inflammation and organ-systemic vascular complications in the brain of aSAH patients. Thereby, the integrity of the bloodbrain barrier plays a major role, although with this study it remains unclear whether suPAR can enter the subarachnoid space secondary to a disruption of the blood-brain barrier or whether it is produced more abundantly in this space (49). Further studies are needed to address this topic. ...