Tibo Gerriets

Potential and Limitations of Transcranial Color-Coded Sonography in Stroke Patients

BACKGROUND AND PURPOSE Transcranial color-coded duplex sonography (TCCS) enables visualization of the intracranial parenchymal structures and measurement of blood flow velocity in the basal cerebral arteries. The present study aims to evaluate prospectively the clinical usefulness of TCCS in patients with acute stroke. METHODS Eighty-four consecutive patients with central nervous symptoms suggesting acute stroke were investigated within the first 48 hours after clinical onset. TCCS was performed with a 2.5-MHz sector transducer through the temporal bone window. CT was available in all patients. RESULTS Forty-eight patients suffered from an infarction or a transient ischemic attack (TIA) in the territory of the middle cerebral artery (MCA). Fifteen of them showed an MCA occlusion, and 12 of the 15 developed recanalization during follow-up. Twelve revealed an increased, decreased, or oscillating flow pattern in the MCA main stem, and 21 patients had no ultrasonic abnormalities. The positive and negative predictive values of a pathological flow pattern in patients with MCA infarctions or TIA were .92 and .48, respectively. Fifteen patients suffered from an intracerebral hematoma, which could be diagnosed by TCCS in 14 cases. The positive and negative predictive values of a pathological parenchymal echo pattern were .88 and .96, respectively. Three patients suffered from an infarction and one from a TIA in the posterior cerebral artery territory. One female patient with an acute deterioration of a hemiparesis showed a glioma. The dropout rate due to an insufficient acoustic temporal bone window was 20% (17/84). CONCLUSIONS TCCS is a noninvasive bedside method that provides rapid and reliable data regarding stroke subtype and mechanism immediately after onset. Window failure is a serious limitation of this method.

Diffusion-Weighted Magnetic Resonance Imaging and Neurobiochemical Markers After Aortic Valve Replacement Implications for Future Neuroprotective Trials?

Background and Purpose— Cardiac surgery carries a high risk of neurological complications; therefore, these patients would be an appropriate target population for neuroprotective strategies. In this study, we evaluated postoperative diffusion-weighted imaging (DWI) as a potential surrogate marker for brain embolism and its relationship to neurobiochemical markers of brain injury. Methods— Of a total of 45 consecutive patients undergoing aortic valve replacement, 37 completed preoperative and postoperative MRI. At the time of the MRI studies, serum S100&bgr; and neuron-specific enolase concentrations were determined. Preexisting T2 and postoperative DWI lesion volumes were quantified. All patients had a blinded neurological examination before and after operation. Results— New perioperative DWI lesions were present in 14 patients (38%), of whom only 3 developed focal neurological deficits. Eighteen small lesions were found in the white matter or vascular border zones in all but 2 patients with territorial stroke. The appearance of new DWI lesions correlated with age, pre-existing T2 lesion volume, and postoperative S100&bgr; concentrations on days 2 to 4 after surgery. In a forward stepwise canonical discrimination model, only T2 lesion volume was selected as a relevant variable. Conclusions— The incidence of postoperative DWI lesions in aortic valve replacement is high, and a suitable marker for neuroprotective trials would be a reduction in the number of such lesions. The volume of preexisting T2 lesions is related to the development of perioperative DWI lesions.

Evaluation of the ventricular system in adults by transcranial duplex sonography.

Transcranial duplex color‐flow sonography provides visualization of intracranial structures, and measures angle‐corrected blood flow velocity in the basal cerebral artenes of adults. In 44 patients with central nervous system disease, the oblique diameters of the third and the middle part of the lateral ventricle were measured by transcranial duplex color‐flow sonography using a system with a 2.5‐MHz transducer, and compared to computed tomography measurements. The correlation coefficients for the third and lateral ventncle measurements were r = 0.83 (p < 0.0001, N = 38) and 0.73 (p < 0.0001, N = 78), respectively. A second investigation was performed by transcranial duplex to evaluate intraobserver and mterobserver reproducibility. The correlation coefficient representing interobserver reproducibility in 27 patients was r = 0.87 (p < 0.0001, N = 47) for the lateral ventricle and r = 0.9 (p < 0.0001, N = 49) for the third ventricle. The intraobserver reproducibility correlation coefficient was r = 0.93 (p < 0.0001, N = 22) for the lateral ventricle in 12 patients. In 49 healthy volunteers the oblique diameters of the lateral and third ventricles were age dependent measuring 16.7 ± 2.3 mm and 4.8 ± 1.9 mm, respectively, in those younger than 59 years, compared to 19.0 ± 2.9 mm and 7.6 ± 2.1 mm in those 60 years or older. Therefore, transcranial duplex color‐flow sonography measures noninvasively the third and the lateral ventncle in adults.

Influence of Recanalization on Outcome in Dural Sinus Thrombosis A Prospective Study

Background and Purpose— Recanalization in dural sinus thrombosis (DST) has been observed previously; however, systematic prospective data are lacking. The influence of recanalization on DST outcome has not yet been thoroughly evaluated. Methods— Thirty-seven consecutive patients with DST were prospectively examined. Neurological deficits were graded with the National Institutes of Health Stroke Scale (NIHSS) on hospital admission and discharge. Functional outcome was assessed with the modified Rankin Scale (mRS) on hospital discharge and after 12 months. All patients were treated with intravenous heparin in the acute stage of illness, followed by oral anticoagulation for 12 months. Imaging follow-up with MR angiography and, in a few cases, with CT or conventional angiography was performed on hospital discharge and after 6 and 12 months. Results— Twelve-month functional outcome was excellent in 89% of patients with an mRS of 0 or 1. A recanalization rate of 60% was already observed on hospital discharge (22±6 days); thereafter, recanalization rates increased insignificantly. Early recanalization was not related to NIHSS score on hospital discharge or an mRS of 0 on discharge or after 12 months. Conclusions— We found a high frequency of early recanalization but without influence on clinical outcome parameters. Frequent imaging follow-ups in DST are not useful because they provide no information on patient outcome.

Neuropsychological decline after catheter ablation of atrial fibrillation

BACKGROUND Cerebral embolic events represent recognized side effects after catheter ablation in the treatment of recurrent atrial fibrillation (AF). OBJECTIVE The study was performed to analyze the neuropsychological outcome and to detect new embolic ischemic brain lesions after therapeutic left atrial catheter ablation of AF. METHODS We enrolled 23 patients with recurrent AF who underwent elective circumferential pulmonary vein isolation. The primary endpoint was the neuropsychological outcome 3 months after intervention in contrast to the results of non-AF controls (n = 23) without ablation and in covariance of baseline performance. Cerebral diffusion-weighted magnetic resonance imaging (DWI) was performed in 21 AF patients at baseline, 2-4 days, and 3 months after intervention. RESULTS In 3/21 patients (14.3%), new ischemic lesions were detected on DWI shortly after intervention. In one patient, a territorial middle cerebral artery infarct occurred with severe clinical symptoms. The other two patients represented clinically silent small lesions. In contrast to the control group and in covariance of baseline performance, the ablation group showed worse neuropsychological outcome in verbal memory (one of five cognitive domains) with an effect size of d = 0.93[t (.05; 42) = -3.53; P < .001; false discovery rate (FDR)(crit) ≤ .01]. CONCLUSION Adverse neuropsychological changes after left atrial catheter ablation are verifiable in verbal memory and, conjoined with ischemic brain lesions on DWI, might represent cerebral side effects of this procedure.

Sonographic Monitoring of Midline Shift in Space-Occupying Stroke An Early Outcome Predictor

Background and Purpose — Transcranial color-coded duplex sonography (TCCS) allows bedside imaging of intracranial hemodynamics and parenchymal structures. It provides reliable information regarding midline shift (MLS) in space-occupying hemispheric stroke. We studied the value of MLS measurement to predict fatal outcome at different time points after stroke onset. Methods — Forty-two patients with acute, severe hemispheric stroke were enrolled. Cranial computed tomography (CCT) and extracranial duplex sonography were performed on admission. TCCS was carried out 8±3, 16±3, 24±3, 32±3, and 40±3 hours after stroke onset. Lesion size was determined from follow-up CCT. Results — Twelve patients died as the result of cerebral herniation (group 1); 28 survived (group 2). Two patients received decompressive hemicraniectomy and were therefore excluded from further evaluation. MLS was significantly higher in group 1 as early as 16 hours after onset of stroke. Specificity and positive predictive values for death caused by cerebral herniation of MLS ≥2.5, 3.5, 4.0, and 5.0 mm after 16, 24, 32, and 40 hours were 1.0. Conclusions — TCCS helps to estimate outcome as early as 16 hours after stroke onset and thus facilitates identification of patients who are unlikely to survive without decompressive craniectomy. Because of its noninvasive character and bedside suitability, sonographic monitoring of MLS might be a useful tool in management of critically ill patients who cannot undergo repeated CCT scans.

Cerebral venous thrombosis: an all or nothing disease? Prognostic factors and long-term outcome

BACKGROUND There is insufficient data on short- and especially long-term prognosis of cerebral venous thrombosis (CVT). METHODS In 79 consecutive patients, we analyzed factors for acute death and functional outcome at hospital discharge and after 6 months as well as long-term prognosis >/=12 months. Neurological deficits were graded on the National Institute of Health Stroke Scale (NIHSS), functional outcome on the modified Rankin Scale (mRS). Primary outcome was defined as mRS >/= 3 at 6 months, secondary outcomes were death during hospital treatment and number as well as type of complications during follow-up >/=12 months after hospital discharge. Forty-two patients were recruited prospectively, 37 were identified by chart review. Information on outcome was based on neurological examinations at our outpatient clinic. RESULTS Factors significantly related to acute death were age, the NIHSS on admission, more than two seizures despite antiepileptic treatment, venous infarct, and hemorrhagic transformation of the venous infarct. Primary outcome after 6 months in 74 patients was excellent with 73% of patients reaching a mRS 0-1, 4% a mRS of 2, and 23% a mRS 3-6, including 12 deaths in the acute stage of illness. Factors significantly related to a mRS >/= 3 at 6 months in a logistic regression analysis were age and items 1a-c of the NIHSS on admission related to consciousness. Fifty-eight surviving patients had a follow-up >/= 12 months (median: 31; mean: 52 +/- 61 months). Most frequent complication on long-term follow-up was epilepsy in nine patients and recurrent venous thrombosis in seven patients. CONCLUSIONS When the acute stage of illness has been survived, CVT has a good prognosis unlike arterial ischemic stroke.

Protecting the brain from gaseous and solid micro-emboli during coronary artery bypass grafting: a randomized controlled trial

AIMS The purpose of the study was to investigate whether intra-operative filter devices protect the brain during coronary artery bypass grafting (CABG) and to determine the impact of solid and gaseous micro-emboli on neuropsychological functioning. METHODS AND RESULTS Patients undergoing CABG received either an intra-aortic filter (Embol-X) (n = 43), designed to reduce solid micro-emboli, a dynamic bubble trap (DBT) (n = 50), designed to reduce gaseous micro-emboli, or no additional device (control group) (n = 50). Cognitive functioning was assessed before and 3 months after CABG. Micro-emboli signals (MES) were detected during surgery using transcranial Doppler (TCD) sonography. Cerebral magnetic resonance imaging (MRI) was carried out before and after surgery. Primary endpoint was the cognitive outcome of the filter groups compared with the controls. Analysis of covariance was performed using the post-operative cognitive test scores as continuous variables in covariance of the corresponding pre-operative scores. Secondary endpoints were the MES rates and the number of acute ischaemic lesions after CABG. Compared with the controls, cognitive functioning of the DBT group was better in executive functioning (t = 2.525, P = 0.0065) and verbal short-term memory (t = 2.420, P = 0.009). The Embol-X group did not perform better in any test. The total number of MES was lower in the DBT group (median 99, P = 0.0019), but not in the Embol-X group (median 162.5, P > 0.05), both compared with controls (median 164.5). After surgery, 17 patients displayed small ischaemic brain lesions on MRI with equal distribution between the groups. CONCLUSION Gaseous micro-embolization contributes to neuropsychological decline, which is measurable 3 months post-operatively. No filter device could protect the brain during CABG completely. However, the use of the DBT tends to improve the cognitive outcome after CABG. Gas filters are recommendable for neuroprotection during cardiac surgery.

DIAS I: Duplex-Sonographic Assessment of the Cerebrovascular Status in Acute Stroke A Useful Tool for Future Stroke Trials

Background and Purpose A number of controlled trials have evaluated the benefit of intravenous thrombolysis in acute stroke with inconsistent results. None of these studies assessed the initial vascular status or provided information regarding the recanalization rate after therapy. Further trials need to clarify whether certain subgroups might possibly benefit more than others from intravenous thrombolysis. Therefore, a fast and valid method for assessment of cerebrovascular status is needed. In this multicenter study, we evaluated the potentials and limitations of color-coded duplex sonography (TCCS) for cerebrovascular status assessment in acute stroke patients before and after therapy. Furthermore, we compared the recanalization rate for patients referred to thrombolytic and conservative medical therapy. Methods Fifty-eight patients suffering from hemispheric stroke were enrolled consecutively in 8 centers. Duplex sonography was performed on admission, 2 hours after start of therapy, and 24 hours after onset of symptoms. Therapy was started within 6 hours. Results Intravenous thrombolysis was performed in 18 patients, conservative medical therapy in 39 patients, and early thromboendarterectomy in 1 patient. The middle cerebral artery (MCA) mainstem was patent in 29 patients (53.7%), occluded in 25 (46.3%), and was not assessable in 4 patients. Recanalization of the occluded MCA after 2 and 24 hours was diagnosed in 50% and 78% of the patients treated with rtPA and in 0% and 8% in the conservatively treated patients. Conclusions Intravenous thrombolysis is highly effective in restoring blood flow after MCA occlusion. TCCS is suitable for assessment of the cerebrovascular status in acute stroke and therefore might define therapeutically relevant subgroups of patients in future stroke trials on the basis of their vascular pathology.

Anemia as a risk factor for cerebral venous thrombosis? An old hypothesis revisited. Results of a prospective study.

BackgroundSeveral case reports have linked iron deficiency anemia with the occurrence of cerebral venous thrombosis (CVT) or stroke, yet, it is unclear whether this is a chance association.MethodsIn a case-control design data of whole blood count and screening for thrombophilic coagulation abnormalities of 121 prospectively identified patients with CVT and 120 healthy controls were compared. Anemia was defined as a hemoglobin (Hb) concentration of <120 g/l in females, and <130 g/l in males, severe anemia as a Hb <90 g/l. Adjusted odds ratios (OR) were calculated based on a logistic regression model treating variables with a level of significance of p ≤0.2 on univariate analysis as potential confounders.ResultsThrombophilia (OR 1.22, 95% CI 1.07-1.76, p < 0.01), severe anemia (OR 1.10, 95% CI 1.01-2.22, p < 0.05), and hypercholesterinemia (OR 1.21, 95% CI 1.04-2.57, p < 0.05) were the only independent variables associated with CVT on multivariate analysis.ConclusionSevere anemia is significantly and independently associated with CVT.