Miguel Bussière

Hemodynamic instability during carotid artery stenting: the relative contribution of stent deployment versus balloon dilation.

OBJECT Hemodynamic instability may complicate carotid angioplasty and stenting in up to 40% of patients. The authors have previously demonstrated that primary self-expanding stent placement alone can gradually dilate severely stenosed carotid arteries without the use of balloons. The authors hypothesized that eliminating the balloon would reduce carotid baroreceptor stimulation, thereby decreasing the incidence of hemodynamic instability. METHODS Ninety-seven high surgical risk patients with symptomatic, severely stenosed carotid arteries were treated with the intention of using a self-expanding stent alone. Seventy-seven arteries (79%) were treated with stenting alone, and 20 required angioplasty (21%). RESULTS Intraprocedural bradycardia (heart rate < 60 bpm) developed in 29 patients (38%) and hypotension (systolic blood pressure < 90 mm Hg) occurred in 1 patient (1%) treated with stenting alone. Fourteen patients (70%) who underwent angioplasty and stenting had bradycardia, and hypotension developed in 4 (20%). Atropine, glycopyrrolate, or vasopressors were required in 8% of patients who received stenting alone, compared to 30% of patients who underwent angioplasty. In the first 24 hours after treatment, hypotension or bradycardia developed in 25 patients (32%) who had undergone stent placement alone, and in 15 patients (75%) after stent placement and balloon angioplasty. There was no difference in the occurrence of intra- or postprocedural hypertension (systolic blood pressure > 160 mm Hg) between patients treated with stenting alone or stenting and balloons. Factors independently associated with hemodynamic depression included baseline heart rate and balloon use. CONCLUSIONS Hemodynamic instability during and after carotid artery stenting was observed more frequently when balloon angioplasty was required than when stent placement was performed without concurrent balloon angioplasty.

Hyperdense Internal Carotid Artery Sign A CT Sign of Acute Ischemia

Background and Purpose— The hyperdense middle cerebral artery sign (HMCAS) is a well-established marker of early ischemia on noncontrast computed tomography of the brain (NCCT). Recently the MCA dot sign has been described and proposed to indicate thrombosis of the M2 or M3 middle cerebral artery branches. The purpose of this study was to define the hyperdense ICA sign (HICAS) and determine its prevalence, diagnostic and prognostic value, and its reliability as a marker for ischemia. Methods— Noncontrast computed tomography scans of 71 patients with acute ischemic stroke were analyzed for the presence of a HICAS, HMCAS, or MCA dot sign. For the validation of HICA and HMCA signs on NCCT, 32 of 71 patients who underwent gold standard CT angiography (CTA) before thrombolytic therapy were included in the analysis. The presence of a HICAS was correlated with initial neurological severity and the short and long-term outcomes. Results— A HICAS was found in 24% of patients on NCCT. In patients with a HICAS, mean age was 63±17.4 and mean time from symptom onset to CT was 103 minutes. Interobserver agreement was excellent for the HICAS. The HICAS has high specificity (100%) and positive predictive value (100%) in predicting the presence of distal internal carotid artery thrombus on CTA. Patients with a HICAS had a more severe initial neurological deficit and worse prognosis than patients without a HICAS. Conclusion— The HICAS is a reliable and a highly specific marker of thromboembolic occlusion of the distal ICA and is associated with severe initial neurological deficit and worse outcome despite thrombolytic therapy.

Prolonged deficits after focal inhibitory seizures

AbstractIntroduction: Seizures are most commonly associated with positive phenomena such as tonic, clonic or myoclonic movements, automatisms, paresthesias and hallucinations. Negative phenomena, however, are not an uncommon manifestation of seizure activity. Examples of negative seizure phenomena include speech arrest, aphasia, amaurosis, amnesia, numbness, deafness, neglect and atonic seizures. Less commonly described in the literature are focal inhibitory motor seizures. Methods and Results: Two patients presenting with rapidly progressive, prolonged hemiparesis, sensory neglect and hemi-visual field obscuration are described. Computed tomography (CT) and magnetic resonance imaging (MRI) of the brain did not reveal progression of known structural lesions or new lesions. The superficial cortex of the hemisphere contralateral to the hemiparesis and sensory neglect enhanced diffusely with gadolinium on T1-weighted MRI images. Electroencephalography demonstrated periodic lateralized epileptiform discharges (PLEDs) in one patient and lateralized suppression and slowing in the other patient. Single photon emission computed tomography (SPECT) revealed hyperperfusion in the hemisphere contralateral to the hemiparesis and sensory neglect. The changes seen on MRI and SPECT resolved with resolution of the symptoms. Conclusion: Taken together with the clinical history, the results from these investigations suggest focal inhibitory seizure as the underlying etiology. A review of the literature and investigations helpful in making this difficult diagnosis are provided.

Transcortical Venous Approach for Direct Embolization of a Cavernous Sinus Dural Arteriovenous Fistula: Technical Case Report

BACKGROUND AND IMPORTANCE: Dural arteriovenous fistulas (dAVFs) represent 10% to 15% of all intracranial arteriovenous malformations. Most often, embolization is accomplished with transfemoral catheter techniques. We present a case in which embolization of a cavernous sinus dAVF was made possible through transcranial cannulation of a cortical draining vein. CLINICAL PRESENTATION: An 82-year-old woman presented with diplopia, left sixth cranial nerve palsy, intraocular hypertension, and bilateral chemosis. Angiography revealed a complex cavernous dAVF with cortical venous reflux, supplied by both external carotid arteries and the left meningohypophyseal trunk. Percutaneous transvenous access failed, and only partial occlusion was achieved by transarterial embolization. A frontotemporal craniotomy was performed to access the superficial middle cerebral vein in the left sylvian fissure. Under fluoroscopic guidance, a microcatheter was advanced through this vein to the floor of the middle cranial fossa and into the dAVF, permitting coil occlusion. CONCLUSION: This transcranial vein technique may be a useful adjunct in dAVF therapy when percutaneous transarterial or transvenous approaches fail or are not possible. ABBREVIATIONS: CVD, cortical venous drainage dAVF, dural arteriovenous fistula ECA, external carotid artery

Auditory-evoked potentials during coma: Do they improve our prediction of awakening in comatose patients?

OBJECTIVE The mismatch negativity (MMN), an auditory event-related potential, has been identified as a good indicator of recovery of consciousness during coma. We explored the predictive value of the MMN and other auditory-evoked potentials including brainstem and middle-latency potentials for predicting awakening in comatose patients after cardiac arrest or cardiogenic shock. MATERIALS AND METHODS Auditory brainstem, middle-latency (Pa wave), and event-related potentials (N100 and MMN waves) were recorded in 17 comatose patients and 9 surgical patients matched by age and coronary artery disease. Comatose patients were followed up daily to determine recovery of consciousness and classified as awakened and nonawakened. RESULTS Among the auditory-evoked potentials, the presence or absence of MMN best discriminated between patients who awakened or those who did not. Mismatch negativity was present during coma in all patients who awakened (7/7) and in 2 of those (2/10) who did not awaken. In patients who awakened and in whom MMN was detected, 3 of those awakened between 2 and 3 days and 4 between 9 and 21 days after evoked potential examination. All awakened patients had intact N100 waves and identifiable brainstem and middle-latency waves. In nonawakened patients, N100 and Pa waves were detected in 5 cases (50%) and brainstem waves in 9 (90%). CONCLUSIONS The MMN is a good predictor of awakening in comatose patients after cardiac arrest and cardiogenic shock and can be measured days before awakening encouraging ongoing life support.

Direct carotid-cavernous fistula causing brainstem venous congestion.

A 39-year-old man who presented with unilateral proptosis and periocular pain rapidly developed reduced consciousness, facial numbness, dysarthria, and gait ataxia from a direct carotid-cavernous fistula (CCF) with drainage into posterior fossa veins. Brain MRI revealed abnormal signal throughout the brainstem, indicative of venous hypertension and edema. Closure of the fistula by detachable balloon eliminated the clinical and imaging abnormalities. This is the fifth reported case of brainstem complications of a direct CCF. It highlights potentially serious complications of this condition and their reversibility with prompt treatment.

Heparin dosing is associated with diffusion weighted imaging lesion load following aneurysm coiling

Background and purpose Diffusion weighted imaging (DWI) may be used to evaluate post-coiling ischemia. Heparinization protocols for cerebral aneurysm coiling procedures differ among operators and centers, with little literature surrounding its effect on DWI lesions. The goal of this study was to determine which factors, including heparinization protocols, may affect DWI lesion load post-coiling. Materials and methods A review of 135 coiling procedures over 5 years at our centre was performed. Procedural data including length of procedure, number of coils used, stent or balloon assistance and operators were collected. Procedures were either assigned as using a bolus dose (>2000 U at any one time) or small aliquots of heparin (≤2000 U). Postprocedure DWI was reviewed and lesions were classified as small (< 5mm), medium (5–10 mm) or large (>10 mm). The cases were then classified into group 1 (≤5 small lesions) or group 2 (>5 small lesions or ≥1 medium or large lesion). Multivariate regression of the procedural variables for the two groups was calculated. A p value of <0.05 was considered significant. Results There were 78 procedures in group 1 and 57 procedures in group 2. Patients who received small aliquots (n=37) versus boluses of heparin (n=98) intraprocedurally had significantly greater frequency and size of DWI lesions (p=0.03). None of the other procedural variables was found to impact on lesion load. Conclusions More substantial DWI lesions were associated with small aliquots of heparin dosage compared with bolus doses. Heparin boluses should be preferentially administered during aneurysm coiling.

Anaemia on Admission is Associated with More Severe Intracerebral Haemorrhage and Worse Outcomes

Background Lower haemoglobin levels may impair cerebral oxygen delivery and threaten tissue viability in the setting of acute brain injury. Few studies have examined the association between haemoglobin levels and outcomes after spontaneous intracerebral haemorrhage. Aims We evaluated whether anaemia on admission was associated with greater intracerebral haemorrhage severity and worse outcome. Methods Consecutive patients with spontaneous intracerebral haemorrhage were analyzed from the Registry of the Canadian Stroke Network. Admission haemoglobin was related to stroke severity (using the Canadian Neurological Scale), modified Rankin score at discharge, and one-year mortality. Adjustment was made for potential confounders including age, gender, medical history, warfarin use, glucose, creatinine, blood pressure, and intraventricular haemorrhage. Results Two thousand four hundred six patients with intracerebral haemorrhage were studied of whom 23% had anaemia (haemoglobin <120 g/l) on admission, including 4% with haemoglobin <100 g/l. Patients with anaemia were more likely to have severe neurological deficits at presentation [haemoglobin ≤100 g/l, adjusted odds ratio 4·04 (95% confidence interval 2·39, 6·84); haemoglobin 101–120 g/l, adjusted odds ratio 1·93 (95% confidence interval 1·43, 2·59), both P < 0·0001]. In nonanticoagulated patients, severe anaemia was also associated with poor outcome (modified Rankin score 4–6) at discharge [haemoglobin ≤100 g/l, adjusted odds ratio 2·42 (95% confidence interval 1·07–5·47), P= 0·034] and increased mortality at one-year [haemoglobin ≤100 g/l, adjusted hazard ratio 1·73 (95% confidence interval 1·22–2·45), P = 0·002]. Conclusions Anaemia on admission is associated with greater intracerebral haemorrhage severity and worse outcomes. The utility of transfusion remains unclear in this setting.

Long-Lasting Functional Disabilities in Patients Who Recover From Coma After Cardiac Operations

BACKGROUND Uncertainty regarding the long-term functional outcome of patients who awaken from coma after cardiac operations is difficult for families and physicians and may delay rehabilitation. We studied the long-term functional status of these patients to determine if duration of coma predicted outcome. METHODS We followed 71 patients who underwent cardiac operations; recovered their ability to respond to verbal commands after coma associated with postoperative stroke, encephalopathy, and/or seizures; and were discharged from the hospital. The Glasgow Outcome Scale Extended (GOSE) was used to assess functional disability 2 to 4 years after discharge. Outcomes were classified as favorable (GOSE scores 7 and 8) and unfavorable (GOSE scores 1-6). RESULTS Of 71 patients identified, 39 were interviewed, 15 died, 1 refused to be interviewed, and 16 were lost to follow-up. Of the 54 patients with completed GOSE evaluations, only 15 (28%) had favorable outcomes. Among patients with unfavorable outcomes, 15 (28%) died, 14 (26%) survived with moderate disabilities, and 10 (18%) had severe disabilities. Factors associated with unfavorable outcomes were increases in duration of coma (p = 0.007), time in intensive care (p = 0.006), length of hospitalization (p = 0.004), and postoperative serum creatine kinase levels (p = 0.006). Only duration of coma was an independent predictor of unfavorable outcome (odds ratio [OR], 1.25; 95% confidence interval [CI], 1.008-1.537; p = 0.042). Patients with durations of coma greater than 4 days were more likely to have unfavorable outcomes (OR, 5.1; 95% CI, 1.3-21.3; p = 0.02). CONCLUSIONS Two thirds of comatose patients who survived to discharge after cardiac operations had unfavorable long-term functional outcomes. A longer duration of unconsciousness is a predictor of unfavorable outcome.

Primary Stenting for Recurrent Stenosis Following Carotid Endarterectomy

BACKGROUND Carotid angioplasty and stenting is an accepted alternative treatment for severe restenosis following carotid endarterectomy. Balloons may not be required to effectively treat these lesions, given their altered histopathology compared to primary atherosclerotic plaque and tendency to be less calcified. Primary stenting using self-expanding stents alone may, therefore, be a safe and effective treatment for restenosis post-carotid endarterectomy. METHODS We review our experience in the treatment of 12 patients with symptomatic severe restenosis following carotid endarterectomy with primary stent placement alone. RESULTS Self-expanding stent placement alone reduced the mean internal carotid artery stenosis from 85% to 29%. Average peak systolic velocity determined at the time of ultrasonography decreased from 480 cm/s at initial presentation to 154 cm/s post-stent deployment and further decreased to 104 cm/s at one year follow-up. The stented arteries remained widely patent with no evidence of restenosis. A single peri-procedural ipsilateral transient ischemic event occurred. There were no cerebral or cardiac ischemic events recorded at one year of follow-up. CONCLUSIONS In this series, primary stent placement without use of angioplasty balloons was a safe and effective treatment for symptomatic restenosis following carotid endarterectomy.