Publications by authors named "Nandavar Shobha"

20 Publications

  • Page 1 of 1

COVID-19-related strokes are associated with increased mortality and morbidity: A multicenter comparative study from Bengaluru, South India.

Int J Stroke 2020 Dec 6:1747493020968236. Epub 2020 Dec 6.

Department of Neurology, NH Institute of Neurosciences, Mazumdar Shaw Medical Center, Bengaluru, Karnataka, India.

Background: COVID-19-related strokes are increasingly being diagnosed across the world. Knowledge about the clinical profile, imaging findings, and outcomes is still evolving. Here we describe the characteristics of a cohort of 62 COVID-19-related stroke patients from 13 hospitals, from Bangalore city, south India.

Objective: To describe the clinical profile, neuroimaging findings, interventions, and outcomes in COVID-19-related stroke patients.

Methods: This is a multicenter retrospective study of all COVID-19-related stroke patients from 13 hospitals from south India; 1st June 2020-31st August 2020. The demographic, clinical, laboratory, and neuroimaging data were collected along with treatment administered and outcomes. SARS-CoV-2 infection was confirmed in all cases by RT-PCR testing. The data obtained from the case records were entered in SPSS 25 for statistical analysis.

Results: During the three-month period, we had 62 COVID-19-related stroke patients, across 13 centers; 60 (97%) had ischemic strokes, while 2 (3%) had hemorrhagic strokes. The mean age of patients was 55.66 ± 13.20 years, with 34 (77.4%) males. Twenty-six percent (16/62) of patients did not have any conventional risk factors for stroke. Diabetes mellitus was seen in 54.8%, hypertension was present in 61.3%, coronary artery disease in 8%, and atrial fibrillation in 4.8%. Baseline National Institutes of Health Stroke Scale score was 12.7 ± 6.44. Stroke severity was moderate (National Institutes of Health Stroke Scale 5-15) in 27 (61.3%) patients, moderate to severe (National Institutes of Health Stroke Scale 16-20) in 13 (20.9%) patients and severe (National Institutes of Health Stroke Scale 21-42) in 11 (17.7%) patients. According to TOAST classification, 48.3% was stroke of undetermined etiology, 36.6% had large artery atherosclerosis, 10% had small vessel occlusion, and 5% had cardioembolic strokes. Three (5%) received intravenous thrombolysis with tenecteplase 0.2 mg/kg and 3 (5%) underwent mechanical thrombectomy, two endovascular and one surgical. Duration of hospital stay was 16.16 ± 6.39 days; 21% (13/62) died in hospital, while 37 (59.7%) had a modified Rankin score of 3-5 at discharge. Hypertension, atrial fibrillation, and higher baseline National Institutes of Health Stroke Scale scores were associated with increased mortality. A comparison to 111 historical controls during the non-COVID period showed a higher proportion of strokes of undetermined etiology, higher mortality, and higher morbidity in COVID-19-related stroke patients.

Conclusion: COVID-19-related strokes are increasingly being recognized in developing countries, like India. Stroke of undetermined etiology appears to be the most common TOAST subtype of COVID-19-related strokes. COVID-19-related strokes were more severe in nature and resulted in higher mortality and morbidity. Hypertension, atrial fibrillation, and higher baseline National Institutes of Health Stroke Scale scores were associated with increased mortality.
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http://dx.doi.org/10.1177/1747493020968236DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7723737PMC
December 2020

Effects of aging on the association between cerebrovascular responses to visual stimulation, hypercapnia and arterial stiffness.

Front Physiol 2014 19;5:49. Epub 2014 Feb 19.

Department of Physiology and Pharmacology, Faculty of Medicine, University of Calgary Calgary, AB, Canada ; Department of Clinical Neurosciences, Faculty of Medicine, University of Calgary Calgary, AB, Canada ; Hotchkiss Brain Institute, Faculty of Medicine, University of Calgary Calgary, AB, Canada ; Faculty of Kinesiology, University of Calgary Calgary, AB, Canada ; The Libin Cardiovascular Institute of Alberta, Faculty of Medicine, University of Calgary Calgary, AB, Canada.

Aging is associated with decreased vascular compliance and diminished neurovascular- and hypercapnia-evoked cerebral blood flow (CBF) responses. However, the interplay between arterial stiffness and reduced CBF responses is poorly understood. It was hypothesized that increased cerebral arterial stiffness is associated with reduced evoked responses to both, a flashing checkerboard visual stimulation (i.e., neurovascular coupling), and hypercapnia. To test this hypothesis, 20 older (64 ± 8 year; mean ± SD) and 10 young (30 ± 5 year) subjects underwent a visual stimulation (VS) and a hypercapnic test. Blood velocity through the posterior (PCA) and middle cerebral (MCA) arteries was measured concurrently using transcranial Doppler ultrasound (TCD). Cerebral and systemic vascular stiffness were calculated from the cerebral blood velocity and systemic blood pressure waveforms, respectively. Cerebrovascular (MCA: young = 76 ± 15%, older = 98 ± 19%, p = 0.004; PCA: young = 80 ± 16%, older = 106 ± 17%, p < 0.001) and systemic (young = 59 ± 9% and older = 80 ± 9%, p < 0.001) augmentation indices (AI) were higher in the older group. CBF responses to VS (PCA: p < 0.026) and hypercapnia (PCA: p = 0.018; MCA: p = 0.042) were lower in the older group. A curvilinear model fitted to cerebral AI and age showed AI increases until ~60 years of age, after which the increase levels off (PCA: R (2) = 0.45, p < 0.001; MCA: R (2) = 0.31, p < 0.001). Finally, MCA, but not PCA, hypercapnic reactivity was inversely related to cerebral AI (MCA: R (2) = 0.28, p = 0.002; PCA: R (2) = 0.10, p = 0.104). A similar inverse relationship was not observed with the PCA blood flow response to VS (R (2) = 0.06, p = 0.174). In conclusion, older subjects had reduced neurovascular- and hypercapnia-mediated CBF responses. Furthermore, lower hypercapnia-mediated blood flow responses through the MCA were associated with increased vascular stiffness. These findings suggest the reduced hypercapnia-evoked CBF responses through the MCA, in older individuals may be secondary to vascular stiffening.
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http://dx.doi.org/10.3389/fphys.2014.00049DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3928624PMC
March 2014

Stroke- on- Awakening: Safety of CT-CTA Based Selection for Reperfusion Therapy.

Can J Neurol Sci 2014 Mar;41(2):182-6

Background: We studied the safety of use of acute reperfusion therapies in patients with stroke- on- awakening using a computed tomographic angiography (Cta) based large vessel occlusion-good scan paradigm in clinical routine.

Methods: the Cta database of the Calgary stroke program was reviewed for the period January 2003-March 2010. patients with stroke-on-awakening with large artery occlusions on Cta, who received conservative, iV thrombolytic and/or endovascular treatment at discretion of the attending stroke neurologist were analyzed. time of onset was defined by the time last seen or known to be normal. Baseline non-contrast Ct scan (nCCt) alberta Stroke program early Ct Score (aSpeCtS) > 7 was considered a good scan. hemorrhage was defined on follow-up brain imaging using eCaSS 3 criteria. independence (mrS≤2) at three months was considered a good clinical outcome. Standard descriptive statistics and multivariable analysis were done.

Results: among 532 patients with large artery occlusions, 70 patients with stroke-on-awakening (13.1%) were identified. the median age was 69.5 (iQr 24) and 41 (58.6%) were female; 41 (58.6%) received anti-platelets only and 29 (41.4%) received thrombolytic treatment [iV-12 (17.1%), iV/ia-12 (17.1%) and ia-5(7.1%)]. unadjusted analysis showed that baseline nCCt aSpeCtS ≤ 7 (p=0.002) and higher nihSS scores (p=0.018) were associated with worse outcomes. there were no ph2 hemorrhages in the iV thrombolytic or endovascular treated group. functional outcome was not different by treatment.

Conclusion: When carefully selected using Ct –Cta, by a good scan (aSpeCtS > 7) occlusion paradigm, acute reperfusion therapies in patients with stroke-on-awakening can be performed safely in clinical routine.
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http://dx.doi.org/10.1017/s0317167100016553DOI Listing
March 2014

Neurovascular decoupling is associated with severity of cerebral amyloid angiopathy.

Neurology 2013 Nov 4;81(19):1659-65. Epub 2013 Oct 4.

From the Department of Radiology, Seaman Family MR Centre (S.P., C.R.M., R.F., B.G.G., E.E.S.), Departments of Clinical Neurosciences (E.D., G.K., N.S., K.S., A.C., N.P., M.J.P., R.F., B.G.G., E.E.S.), Physiology and Pharmacology (C.D.S., A.B., D.F., M.J.P.), and Community Health Sciences (G.H.F., E.E.S.), University of Calgary, Canada; Institute of Human Movement Sciences and Sport (D.F.), ETH Zurich, Switzerland; Hotchkiss Brain Institute (M.J.P., R.F., B.G.G., E.E.S.), and Faculty of Kinesiology (M.J.P.), University of Calgary; Foothills Medical Centre, Alberta Health Services, Canada.

Objectives: We used functional MRI (fMRI), transcranial Doppler ultrasound, and visual evoked potentials (VEPs) to determine the nature of blood flow responses to functional brain activity and carbon dioxide (CO2) inhalation in patients with cerebral amyloid angiopathy (CAA), and their association with markers of CAA severity.

Methods: In a cross-sectional prospective cohort study, fMRI, transcranial Doppler ultrasound CO2 reactivity, and VEP data were compared between 18 patients with probable CAA (by Boston criteria) and 18 healthy controls, matched by sex and age. Functional MRI consisted of a visual task (viewing an alternating checkerboard pattern) and a motor task (tapping the fingers of the dominant hand).

Results: Patients with CAA had lower amplitude of the fMRI response in visual cortex compared with controls (p = 0.01), but not in motor cortex (p = 0.22). In patients with CAA, lower visual cortex fMRI amplitude correlated with higher white matter lesion volume (r = -0.66, p = 0.003) and more microbleeds (r = -0.78, p < 0.001). VEP P100 amplitudes, however, did not differ between CAA and controls (p = 0.45). There were trends toward reduced CO2 reactivity in the middle cerebral artery (p = 0.10) and posterior cerebral artery (p = 0.08).

Conclusions: Impaired blood flow responses in CAA are more evident using a task to activate the occipital lobe than the frontal lobe, consistent with the gradient of increasing vascular amyloid severity from frontal to occipital lobe seen in pathologic studies. Reduced fMRI responses in CAA are caused, at least partly, by impaired vascular reactivity, and are strongly correlated with other neuroimaging markers of CAA severity.
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http://dx.doi.org/10.1212/01.wnl.0000435291.49598.54DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3812103PMC
November 2013

A risk score for in-hospital death in patients admitted with ischemic or hemorrhagic stroke.

J Am Heart Assoc 2013 Jan 28;2(1):e005207. Epub 2013 Jan 28.

Department of Clinical Neurosciences, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada.

Background: We aimed to derive and validate a single risk score for predicting death from ischemic stroke (IS), intracerebral hemorrhage (ICH), and subarachnoid hemorrhage (SAH).

Methods And Results: Data from 333 865 stroke patients (IS, 82.4%; ICH, 11.2%; SAH, 2.6%; uncertain type, 3.8%) in the Get With The Guidelines-Stroke database were used. In-hospital mortality varied greatly according to stroke type (IS, 5.5%; ICH, 27.2%; SAH, 25.1%; unknown type, 6.0%; P<0.001). The patients were randomly divided into derivation (60%) and validation (40%) samples. Logistic regression was used to determine the independent predictors of mortality and to assign point scores for a prediction model in the overall population and in the subset with the National Institutes of Health Stroke Scale (NIHSS) recorded (37.1%). The c statistic, a measure of how well the models discriminate the risk of death, was 0.78 in the overall validation sample and 0.86 in the model including NIHSS. The model with NIHSS performed nearly as well in each stroke type as in the overall model including all types (c statistics for IS alone, 0.85; for ICH alone, 0.83; for SAH alone, 0.83; uncertain type alone, 0.86). The calibration of the model was excellent, as demonstrated by plots of observed versus predicted mortality.

Conclusions: A single prediction score for all stroke types can be used to predict risk of in-hospital death following stroke admission. Incorporation of NIHSS information substantially improves this predictive accuracy.
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http://dx.doi.org/10.1161/JAHA.112.005207DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3603253PMC
January 2013

Measurement of length of hyperdense MCA sign in acute ischemic stroke predicts disappearance after IV tPA.

J Neuroimaging 2014 Jan-Feb;24(1):7-10. Epub 2013 Jan 14.

Department of Clinical Neurosciences, University of Calgary, Calgary, Alberta, Canada.

Background: We sought to assess the hypothesis that length and volumes of middle cerebral artery (MCA) thrombus were associated with disappearance of the hyperdense middle cerebral artery sign (HMCAS) in acute ischemic stroke.

Methods: This is a retrospective cohort study of acute ischemic stroke patients with MCA occlusion admitted to the University Hospital in Canada. The length and volumes of the HMCAS was measured on the plain CT by placing CTA images (CTA source images or MIP images) side-by-side.

Results: Seventy-six patients with acute stroke having HMCAS on noncontrast CT (NCCT) with M1 MCA occlusion confirmed by CT angiography or digital subtraction angiography and received tPA. The treatments received were: IV tPA 41(53.9%) and endovascular treatment ± IV tPA 35 (46.1%). In the IV tPA group, the rate of disappearance varied depending on the baseline HMCAS length. Short length HMCAS (<10 mm) disappeared in 6/7 (85.7%) (P < .001). Medium length HMCAS (10-20 mm) disappeared in 9/24 (37.5%). No cases of long length HMCAS (>20 mm) disappeared (0/10) (P = .05). Rate of disappearance of HMCAS was found to be volume dependent (P < .002).

Conclusion: HMCAS length >10 mm infrequently disappears with IV tPA suggesting a potential need for ancillary therapy in this group.
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http://dx.doi.org/10.1111/j.1552-6569.2012.00761.xDOI Listing
April 2015

Do lacunar strokes benefit from thrombolysis? Evidence from the Registry of the Canadian Stroke Network.

Int J Stroke 2013 Oct 11;8 Suppl A100:45-9. Epub 2012 Dec 11.

Bangalore Neuro Centre, Vagus Superspeciality hospital, Bhagwan Mahaveer Jain hospital, Vikram Hospital, Bangalore, India.

Background: Lacunar infarcts constitute up to 25% of all ischaemic strokes. As acute intracranial vascular imaging has become widely available with computed tomographic angiography, thrombolysis of lacunar strokes has become contentious because an intracranial vascular lesion cannot be visualized. We studied the effect of thrombolysis on lacunar strokes compared to other clinical ischaemic stroke sub-types.

Methods: Ischaemic stroke patients from phase 3 of the Registry of the Canadian Stroke Network data (July 2003-March 2008) were included. Lacunar stroke was defined as a lacunar syndrome supported by computed tomography brain showing a subcortical hypodense lesion with a diameter <20 mm. Clinical syndromes were used to define other stroke sub-types. The outcomes were mortality at 90 days, modified Rankin Scale score 0-2 at discharge, occurrence of intracranial haemorrhage as a complication of stroke in-hospital, and discharge disposition to home.

Results: A total of 11,503 patients of ischaemic stroke were included from the Registry of the Canadian Stroke Network 3 between July 2003 and March 2008. Lacunar strokes formed 19.1% of the total strokes. The total number of patients who received tissue plasminogen activator was 1630 (14.2%). A significant association was found between tissue plasminogen activator treatment and outcomes after controlling Oxfordshire Community Stroke Project types--for modified Rankin Scale at discharge and discharge to home, but not for mortality. A thrombolysis-by-Oxfordshire Community Stroke Project stroke sub-type interaction was observed due to lack of benefit among the posterior circulation stroke sub-types. Patients with lacunar strokes, partial anterior circulation stroke, and total anterior circulation strokes all benefited approximately equally from thrombolysis.

Conclusions: Thrombolysis is associated with clinically improved outcome among patients with lacunar stroke syndromes.
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http://dx.doi.org/10.1111/j.1747-4949.2012.00932.xDOI Listing
October 2013

Combined full-dose IV and endovascular thrombolysis in acute ischaemic stroke.

Int J Stroke 2014 Dec 27;9(8):974-9. Epub 2012 Sep 27.

Department of Neurology, All India Institute of Medical Sciences, New Delhi, India.

Background: There is an increasing trend to treating proximal vessel occlusions with intravenous-inter-arterial (IV-IA) thrombolysis. The best dose of IV tissue plasminogen activator (tPA) remains undetermined. We compared the combination of full-dose IV recombinant tissue plasminogen activator (rtPA) and IA thrombolytic therapy to IA therapy.

Methods: Between 2002 and 2009, we reviewed our computed tomographic angiography database for patients who received full-dose intravenous rtPA and endovascular therapy or endovascular therapy alone for acute ischaemic stroke treatment. Details of demographics, risk factors, endovascular procedure, and symptomatic intracranial haemorrhage were noted. Modified Rankin Scale ≤2 at three-months was used as good outcome. Recanalization was defined as Thrombolysis in Myocardial Ischaemia 2-3 flow on angiography.

Results: Among 157 patients, 104 patients received IV-IA treatment and 53 patients underwent direct IA therapy. There was a higher recanalization rate with IV-IA therapy compared with IA alone (71% vs. 60%, P < 0·21) which was driven by early recanalization after IV rtPA. Mortality and independent outcome were comparable between the two groups. Symptomatic intracranial haemorrhage occurred in 8% of patients (12% in the IA group, 7% in the IV-IA group) but was more frequent as the intensity of intervention increased from device alone to thrombolytic drug alone to device plus thrombolytic drug(s). Recanalization was a strong predictor of reduced mortality risk ratio (RR) 0·48 confidence interval95 0·27-0·84) and favourable outcome (RR 2·14 confidence interval95 1·3-3·5).

Conclusions: Combined IV-IA therapy with full-dose intravenous rtPA was safe and results in good recanalization rates without excess symptomatic intracranial haemorrhage. Testing of full-dose IV tPA followed by endovascular treatment in the IMS3 trial is justified.
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http://dx.doi.org/10.1111/j.1747-4949.2012.00890.xDOI Listing
December 2014

Time dependence of reliability of noncontrast computed tomography in comparison to computed tomography angiography source image in acute ischemic stroke.

Int J Stroke 2015 Jan 13;10(1):55-60. Epub 2012 Sep 13.

Department of Clinical Neurosciences, Hotchkiss Brain Institute University of Calgary, Calgary, Alberta, Canada; Section of Neurology, Department of Internal Medicine, Health sciences Centre, Winnipeg, Canada.

There is no consensus on how the reliability and predictive ability of noncontrast computed tomography (NCCT) and computed tomography angiography source image (CTASI) change over time from acute ischemic stroke onset. We hypothesized that the reliability for detecting early ischemic changes (EIC) would be lower in early time periods and that changes identified on CTASI would be more reliable across examiners than changes identified on NCCT. To address this, we compared the relationships between CTASI, NCCT, and final infarct in patients with initial computed tomography (CT) imaging at different time points after stroke onset. Patients with acute ischemic stroke with proximal anterior circulation occlusions (internal carotid artery, middle carotid artery M1, proximal M2) from Calgary CT Angiography (CTA) database were studied. The cohort was categorized in four groups based on time from stroke onset to baseline NCCT/CTA: 0-90 mins (n = 69), 91-180 mins (n = 88), 181-360 mins (n = 46), and >360 mins (n = 58). Median scores of NCCT-Alberta Stroke Program Early CT Score (ASPECTS), CTASI ASPECTS, and follow-up ASPECTS among different time categories were compared. To determine reliability, a subsample of NCCT brain and CTASI were interpreted at separate sessions weeks apart by two neuroradiologists and two stroke neurologists in random order. Median and mean ASPECTS ratings on NCCT and CTASI were higher than final ASPECTS in each time category (P < 0·001 for all comparisons). CTASI ASPECTS was lower than NCCT ASPECTS in each time category, and differences were significant at 0-90 mins and 91-180 mins (P < 0·001). The least agreement among readers was in detection of EIC on NCCT brain in the ultra-early phase (<90 mins) [intraclass correlation coefficient (ICC) = 0·48. By contrast, there was excellent agreement on EIC on CTASI regardless of time period (ICC = 0·87-0·96). Using ASPECTS methodology, CTASI is more reliable than NCCT at predicting final infarct extent particularly in the early time windows.
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http://dx.doi.org/10.1111/j.1747-4949.2012.00859.xDOI Listing
January 2015

Multimodal imaging tools for diagnosis of fat embolism.

J Emerg Trauma Shock 2011 Apr;4(2):306-8

Department of Clinical Neurosciences, Calgary Stroke Program, Calgary, Canada.

It is important to consider several differential diagnoses in a patient presenting with altered sensorium following surgery. Fat embolism syndrome (FES) is a serious condition that needs to be excluded. Although criteria for diagnosis of FES are available, all patients may not satisfy them. We discuss a patient who presented with an incomplete triad of the FES, where the diagnosis was supported by transcranial doppler monitoring of microembolic signals and magnetic resonance imaging.
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http://dx.doi.org/10.4103/0974-2700.82232DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3132374PMC
April 2011

Aphemia as a presenting symptom in acute stroke.

Neurol India 2011 May-Jun;59(3):432-4

Department of Clinical Neurosciences, University of Calgary, Calgary, AB, Canada.

Aphemia is an apraxia of speech characterized by complete articulatory failure in the presence of preserved writing, comprehension and oropharyngeal function and can be the presenting manifestation of acute stroke. The responsible lesion is commonly in the left inferior frontal gyrus or the left motor cortex near the face M1 area. Three patients who developed aphemia due to acute ischemic stroke are described here. All had apraxia of speech due to acute infarct in the left motor cortex near face M1 area. Understanding the underlying speech disorder is crucial in planning the appropriate rehabilitation strategy.
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http://dx.doi.org/10.4103/0028-3886.82766DOI Listing
September 2011

Outcomes in acute ischemic strokes presenting with disabling neurologic deficits without intracranial vascular occlusion.

Int J Stroke 2011 Oct 6;6(5):392-7. Epub 2011 Jun 6.

Department of Clinical Neurosciences, Calgary Stroke Program, Foothills Medical Centre, University of Calgary, Calgary, Alberta, Canada.

Background: Patients with moderate to severe acute ischemic stroke without intracranial vessel occlusion are an intriguing subset of stroke patients. They pose diagnostic and therapeutic challenges to the physician. We sought to study these patients with an emphasis on their radiological and clinical outcomes.

Methods: This is a retrospective cohort study of ischemic stroke patients (NIHSS≥6), with no intracranial vessel occlusion on computed tomography angiography within six-hours of symptom onset. Follow-up imaging - either computed tomography brain or magnetic resonance imaging - was performed within one- to seven-days. The primary outcome was modified Rankin Scale score≤2 at three-months.

Results: In a database of 1308 patients, we identified 99 (7·6%) patients with NIHSS≥6 and no intracranial vessel occlusion on computed tomography angiography. The mean age was 67·8 ± 15·4 years and 60 (60·6%) were men. The median baseline NIHSS was nine (6-28). The initial computed tomography head was normal in 79 (79·8%) patients. Dramatic early clinical improvement at 24 h (NIHSS score ≤2 at 24 h or change between baseline and 24 h NIHSS score ≥15 points) was seen in 38 (38·4%) patients. Follow-up scans showed infarcts in 66 (66·7%) patients. Fifty (50·5%) patients received tissue plasminogen activator; one (2%) tissue plasminogen activator-treated patient developed symptomatic intracranial hemorrhage. At three-months; 59 (59·6%) patients were independent (modified Rankin Scale≤2), 34 (34·3%) patients were dependent (modified Rankin Scale 3-5), and six (6·1%) were dead. The factors associated with the unlikelihood of good outcome were higher initial NIHSS (odds ratio 0·86 per additional point, 95% confidence interval 0·77-0·95, P=0·003), and older age (odds ratio 0·95 per additional year, 95% confidence interval 0·92-0·98, P=0·004).

Conclusion: Stroke without intracranial occlusions are not a benign entity. Factors that are independently associated with decreased likelihood of a good outcome are higher baseline NIHSS, and older age. Treatment with tissue plasminogen activator is not a predictor of outcome.
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http://dx.doi.org/10.1111/j.1747-4949.2011.00607.xDOI Listing
October 2011

CT angiographic source images predict outcome and final infarct volume better than noncontrast CT in proximal vascular occlusions.

Stroke 2011 Jun 12;42(6):1575-80. Epub 2011 May 12.

Department of Neurology, All India Institute of Medical Sciences, New Delhi, India.

Background And Purpose: Alberta Stroke Programme Early CT Score (ASPECTS) is widely used for assessment of early ischemic changes in acute stroke. We hypothesized that CT angiography source image (CTA-SI) ASPECTS correlates better with baseline National Institutes of Health Stroke Scale score, final ASPECTS and neurological outcomes when compared with noncontrast CT ASPECTS.

Methods: We studied patients presenting with acute ischemic stroke and identified proximal arterial occlusions (internal carotid artery, middle cerebral artery M1, and proximal middle cerebral artery M2) from the Calgary CT Angiography database. CT scans were independently read by 3 observers for baseline noncontrast CT ASPECTS, CT angiography source image ASPECTS, and follow-up ASPECTS. Details of demographics and risk factors were noted. A modified Rankin Scale score ≤2 at 3 months was considered a favorable outcome.

Results: We identified 261 patients with proximal occlusions for analysis. We found a better correlation between CT angiography source image ASPECTS and follow-up ASPECTS (Spearman correlation coefficient r=0.65; 95% CI, 0.58 to 0.72; P<0.001) than between noncontrast CT ASPECTS and follow-up CT ASPECTS (r=0.46; 95% CI, 0.36 to 0.55; P<0.001). CT angiography source image ASPECTS correlated better with baseline National Institutes of Health Stroke Scale and 24-hour National Institutes of Health Stroke Scale when compared with noncontrast CT ASPECTS (P<0.001). In an adjusted model including both CT angiography source image ASPECTS and noncontrast CT ASPECTS, CT angiography source image ASPECTS was associated with good outcome (OR, 2.30; 95%, CI, 1.16 to 4.53), whereas noncontrast CT ASPECTS was not (OR, 1.54; 95% CI, 0.84 to 2.82). Among imaging parameters, CT angiography source image ASPECTS was the only independent predictor of good outcome (OR, 2.29; 95% CI, 1.16 to 4.53).

Conclusions: CT angiography source image ASPECTS correlates better with baseline stroke severity, is a better predictor of final infarct extension, and independently predicts neurological outcome than noncontrast CT ASPECTS.
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http://dx.doi.org/10.1161/STROKEAHA.110.603936DOI Listing
June 2011

Thrombolysis at 3-4.5 hours after acute ischemic stroke onset--evidence from the Canadian Alteplase for Stroke Effectiveness Study (CASES) registry.

Cerebrovasc Dis 2011 21;31(3):223-8. Epub 2010 Dec 21.

Calgary Stroke Program, Department of Clinical Neurosciences, Foothills Medical Center, University of Calgary, Calgary, Alberta, Canada.

Background: Extending the therapeutic window for thrombolysis is an important strategy in maximizing the proportion of patients treated. ECASS III examined a 3-4.5-hour window and showed a benefit to treated patients. We examined the experience in Canadian centres using intravenous tPA treatment in the 3-4.5-hour time window.

Methods: The data were obtained from the CASES (Canadian Alteplase for Stroke Effectiveness Study)--a prospective, multicentric cohort study with patient enrollment from 60 centres across Canada over 2.5 years. The 90-day outcome, mortality and symptomatic intracranial hemorrhage of patients thrombolysed between 3 and 4.5 h and within 3 h of symptom onset were compared. A mRS 0-1 (no symptoms at all or no significant disability despite symptoms, able to carry out all usual duties and activities) at 90 days was defined as a favorable outcome.

Results: A total of 1,112 patients with complete data were included. 129 (11.6%) patients received tPA between 3 and 4.5 h of symptom onset and 983 (88.4%) patients received tPA within 3 h. At 90 days, 39.4% of the patients in the 3-4.5-hour treatment group and 36.5% of patients in the under 3-hour treatment group attained a mRS ≤1. There were no differences between the two groups regarding their functional status at 3 months. There was a trend towards higher rate of sICH in the 3-4.5-hour group compared to the 0-3-hour group (7.8 vs. 3.8%, p = 0.06). Similarly there was a trend towards higher rate of deaths in the 3-4.5-hour group compared to the 0-3-hour group (28.4 vs. 21.4%, p = 0.09). A χ(2) test for trend demonstrated a rising proportion of symptomatic ICH in later time windows (p = 0.013). A similar trend (non-significant) was observed for mortality.

Conclusion: Our study suggests that patients with acute ischemic stroke may be successfully treated with intravenous tPA in the 3-4.5-hour treatment window, but cautions that later time window treatment may result in greater adverse events.
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http://dx.doi.org/10.1159/000321893DOI Listing
June 2011

Risk score for in-hospital ischemic stroke mortality derived and validated within the Get With the Guidelines-Stroke Program.

Circulation 2010 Oct 27;122(15):1496-504. Epub 2010 Sep 27.

Calgary Stroke Program, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada.

Background: There are few validated models for prediction of in-hospital mortality after ischemic stroke. We used Get With the Guidelines-Stroke Program data to derive and validate prediction models for a patient's risk of in-hospital ischemic stroke mortality.

Methods And Results: Between October 2001 and December 2007, there were 1036 hospitals that contributed 274,988 ischemic stroke patients to this study. The sample was randomly divided into a derivation (60%) and validation (40%) sample. Logistic regression was used to determine the independent predictors of mortality and to assign point scores for a prediction model. We also separately derived and validated a model in the 109,187 patients (39.7%) with a National Institutes of Health Stroke Scale (NIHSS) score recorded. Model discrimination was quantified by calculating the C statistic from the validation sample. In-hospital mortality was 5.5% overall and 5.2% in the subset in which NIHSS score was recorded. Characteristics associated with in-hospital mortality were age, arrival mode (eg, via ambulance versus other mode), history of atrial fibrillation, previous stroke, previous myocardial infarction, carotid stenosis, diabetes mellitus, peripheral vascular disease, hypertension, history of dyslipidemia, current smoking, and weekend or night admission. The C statistic was 0.72 in the overall validation sample and 0.85 in the model that included NIHSS score. A model with NIHSS score alone provided nearly as good discrimination (C statistic 0.83). Plots of observed versus predicted mortality showed excellent model calibration in the validation sample.

Conclusions: The Get With the Guidelines-Stroke risk model provides clinicians with a well-validated, practical bedside tool for mortality risk stratification. The NIHSS score provides substantial incremental information on a patient's short-term mortality risk and is the strongest predictor of mortality.
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http://dx.doi.org/10.1161/CIRCULATIONAHA.109.932822DOI Listing
October 2010

Low rates of acute recanalization with intravenous recombinant tissue plasminogen activator in ischemic stroke: real-world experience and a call for action.

Stroke 2010 Oct 9;41(10):2254-8. Epub 2010 Sep 9.

Department of Clinical Neurosciences, Foothills Hospital, University of Calgary, Calgary, Alberta, Canada.

Background And Purpose: Acute rates of recanalization after intravenous (IV) recombinant tissue plasminogen activator (rt-PA) in proximal vessel occlusion have been estimated sparingly, typically using transcranial Doppler (TCD). We aimed to study acute recanalization rates of IV rt-PA in CT angiogram-proven proximal (internal carotid artery [ICA], M1 middle cerebral artery [MCA], M2-MCA, and basilar artery) occlusions and their effects on outcome.

Materials And Methods: The CT angiogram database of the Calgary stroke program was reviewed for the period 2002 to 2009. All patients with proximal vessel occlusions receiving IV rt-PA who were assessed for recanalization by TCD or angiogram (for acute endovascular treatment) were included for analysis. Rates of acute recanalization as observed on TCD/first run of angiogram and postendovascular therapy recanalization rates were noted. Modified Rankin Scale score ≤2 at 3 months was used as a good outcome.

Results: Among 1341 patients in the CT angiogram database, 388 patients with proximal occlusion were identified. Of these, 216 patients had received IV rt-PA; 127 patients underwent further imaging to assess recanalization. Among the patients undergoing TCD (n=46) and cerebral angiogram (n=103), only 27 (21.25%) patients had acute recanalization. By occlusion subtype, the rates of recanalization were: distal ICA (with or without ICA neck occlusion or stenotic disease) 1 of 24 (4.4%); M1-MCA (with or without ICA neck occlusion or stenotic disease) 21 of 65 (32.3%); M2-MCA 4 of 13 (30.8%); and basilar artery 1 of 25 (4%). Onset to rt-PA time was comparable in patients with and without recanalization. Recanalization (P<0.0001; risk ratio, 2.7; 95% confidence interval, 1.5-4.6) was the strongest predictor of outcome (adjusted for age and National Institutes of Health Stroke Scale score).

Conclusions: A low rate of acute recanalization was observed with IV rt-PA in proximal vessel occlusions identified by baseline CT angiogram. Recanalization was the strongest predictor of good outcome.
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http://dx.doi.org/10.1161/STROKEAHA.110.592535DOI Listing
October 2010

Carotid angioplasty and stenting is safe in women.

Can Assoc Radiol J 2012 Aug 6;63(3 Suppl):S18-22. Epub 2010 Aug 6.

Department of Clinical Neurosciences, University of Calgary, Calgary, Alberta, Canada.

Background: Results of randomized controlled trials have shown that carotid endarterectomy poses greater perioperative risks to women than to men. There are limited studies regarding sex differences in carotid angioplasty and stenting.

Objectives: To compare male and female patients undergoing carotid stenting with regard to their intraprocedural complications and 30-day outcome.

Methods: We reviewed patients who underwent carotid stenting between 1997 and 2007 at our tertiary centre. Distal protection devices were used in all patients after 1999. Demographics, risk factors, intraprocedural complications, and 30-day outcomes were compared between female and male patients.

Results: Among 243 patients who underwent 255 procedures, 67 were women (27.6%). The mean (SD) age of the female patients was 72.2 ± 8.4 years and that of the male patients was 72.0 ± 9.6 years (P = .83). The majority of patients had symptomatic carotid artery disease; 11 women (16.4%) and 30 men (16.0%) were asymptomatic. The following intraprocedural complications were noticed in female vs male patients: asymptomatic carotid and/or iliac dissections 7.5% vs 0% (P = .001), minor stroke 0% vs 1.1% (P = 1.00), major stroke 0% vs 0.5% (P = 1.00), and cardiac dysrhythmias 3% vs 2.7% (P = 1.00). At 30 days, the outcomes in women vs men were as follows: mortality 3.0% vs 3.2% (P = 1.00), major stroke 3.0% vs 2.1 % (P = .66), and minor stroke 3.0% vs 3.2% (P = 1.00).

Conclusion: Although minor asymptomatic intraprocedural dissections were more common in women, we did not find any impact of sex on the 30-day outcome. We concluded that carotid stenting can be performed as safely in women as in men.
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http://dx.doi.org/10.1016/j.carj.2010.06.005DOI Listing
August 2012

Dental procedures and stroke: a case of vertebral artery dissection.

J Can Dent Assoc 2010 ;76:a82

Department of Clinical Neurosciences, Calgary Stroke Program, University of Calgary, Calgary, Alberta.

As vertebral artery dissections may cause stroke, they must be identified and treated promptly. The association of arterial dissection with dental procedures has been previously observed. In this article, we report on a patient presenting with posterior circulation stroke secondary to vertebral artery dissection following a dental procedure. The clinical course, radiologic findings and management are described and the literature regarding vertebral dissections is reviewed.
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November 2010

Small vessel infarcts and microbleeds associated with radiation exposure.

Can J Neurol Sci 2009 May;36(3):376-8

Calgary Stroke Program, Department of Clinical Neurosciences, Room 1162, Foothills Medical Centre, 1403-29 Street NW, Calgary, Alberta T2N 2T9, Canada.

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http://dx.doi.org/10.1017/s0317167100007162DOI Listing
May 2009

Thrombolysis in aphemia.

N Z Med J 2009 May 8;122(1294):96-8. Epub 2009 May 8.

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May 2009