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Biomedical subjects

R von Kummer

Publications and source records attributed to R von Kummer.

At least 19 recordsLinked to original sources
PubMed2002

What is effective in malignant middle cerebral artery infarction: reperfusion, craniectomy, or both? An experimental study in rats.

BACKGROUND AND PURPOSE: We sought to evaluate the effects of reperfusion and craniectomy treatment at different time points after middle cerebral artery (MCA) occlusion on infarct volume and neurological outcome in MCA infarction in rats. METHODS: We used an endovascular technique to obtain MCA occlusion in 182 rats. Thirteen groups with 14 animals each were investigated: control group 1 with no treatment; groups 2 to 7 with only reperfusion or craniectomy at 1, 4, or 12 hours, respectively; and groups 8 to 13 with reperfusion at 1 or 4 hours combined with craniectomy at 1, 4, or 12 hours, respectively. We used infarct volume and neurological performance as study end points in all animals at day 7. RESULTS: Neurological score and infarct volume in animals undergoing early reperfusion at 1 hour were significantly smaller (1.8/79+/-59 mm3) than those in control animals (3.8/225+/-26 mm3) (P<0.01). Reperfusion at 4 hours (2.8/182+/-62 mm3) and 12 hours (3.7/231+/-69 mm3) did not result in significant improvement. Animals undergoing craniectomy at 1, 4, and 12 hours demonstrated significantly better outcome and significantly reduced infarct volume (1.6/96+/-30 mm3, 1.9/109+/-39 mm3, and 2.6/150+/-34 mm3, respectively) (P<0.05). Compared with 1 treatment at a time, combined reperfusion and craniectomy did not result in a significant additional benefit. CONCLUSIONS: Early reperfusion and craniectomy at 1 hour are both effective in large MCA infarction. While reperfusion later than 1 hour was not beneficial, late craniectomy at 4 and 12 hours still resulted in significant improvement of neurological score and reduction of infarction size. Combined treatment at different time points yields no significant additional benefit compared with 1 treatment at a time.

Acute Disease↗
PubMed2001

Ultrasound in acute stroke: a review.

Ultrasound is widely used for assessment of neurovascular disease, mainly during the subacute or chronic phases of cerebral ischaemia. The availability of aggressive and potentially harmful treatments for acute ischaemic stroke demands fast, and noninvasive examination of the intracranial vasculature. Current ultrasound techniques have the potential to provide essential information about the intracranial arteries in acute stroke. Application of echo-enhancing agents promises to effectively extend current techniques. The clinical significance of sonography in acute stroke needs to be evaluated prospectively and compared with other radiological techniques.

Carotid Arteries↗
PubMed2001

EFNS Task Force on Teaching of Neuroimaging in Neurology Curricula in Europe: present status and recommendations for the future.

A Task Force on 'Teaching of Neuroimaging in Neurology Curricula in Europe' was appointed in September 1998 by the education committee of the European Federation of Neurological Societies (EFNS) in order to: (1) examine the present status of teaching of neuroimaging in the training of neurology in European countries, and, in particular, to assess the strengths and weaknesses of the various countries; (2) give recommendations for global improvement and harmonization of such training. A questionnaire was completed in February 1999 and sent to 35 delegates of national neurological societies. Completed questionnaires were received from 21 countries: Albania, Austria, Croatia, Czech Republic, Denmark, Estonia, Finland, Germany, Greece, Hungary, Israel, Italy, Netherlands, Norway, Poland, Portugal, Slovakia, Spain, Switzerland, Turkey and UK. The questionnaire revealed that the situation in Europe is highly heterogeneous, both as regards the training in neurology in general and, more specifically, the teaching of neuroimaging during the training. Some recommendations to make the teaching of neuroimaging more homogeneous across European countries and to improve it are provided.

Curriculum↗
PubMed2001

Early prediction of irreversible brain damage after ischemic stroke at CT.

PURPOSE: To assess the capability of computed tomography (CT) in the prediction of irreversible ischemic brain damage and its association with the clinical course within 6 hours of stroke onset. MATERIALS AND METHODS: Serial CT scans obtained within 6 hours of stroke onset, at 22-96 hours (median, 1 day), and at 2-36 days (median, 7 days) after symptom onset in 786 patients with ischemic stroke were prospectively studied, and follow-up CT scans were used as the reference. Clinical variables were assessed prospectively and independently of CT evaluation. RESULTS: The specificity and positive predictive value of ischemic edema at baseline CT for brain infarcts were 85% (95% CI: 77%, 91%) and 96% (95% CI: 94%, 98%), respectively. Sensitivity and negative predictive values were 64% (95% CI: 60%, 67%) and 27% (95% CI: 23%, 32%), respectively. Patients without early CT findings were less severely affected (P<.001), developed smaller infarcts (P<.001), had fewer intracranial bleeding events (P<.001), and had a better clinical outcome at 90 days (P<.001) compared with patients with hypoattenuating brain tissue at early CT. CONCLUSION: After ischemic stroke, x-ray hypoattenuation at CT is highly specific for irreversible ischemic brain damage if detection occurs within the first 6 hours. Patients without hypoattenuating brain tissue have a more favorable clinical course.

Adolescent↗
PubMed2001

Echo-enhanced transcranial color-coded duplexsonography to study collateral blood flow in patients with symptomatic obstructions of the internal carotid artery and limited acoustic bone windows.

We prospectively evaluated 30 consecutive patients with echo-enhanced transcranial color-coded duplexsonography (TCCD) and correlative transfemoral digital subtraction angiography to assess the diagnostic efficacy of echo-enhanced TCCD for evaluation of collateral pathways through the circle of Willis in patients with limited acoustic bone windows and critical symptomatic carotid disease. Echo-enhanced TCCD detected collateral blood flow through the anterior communicating artery in 16 of 18 patients (sensitivity 89%, 95% CI 65-99%) and was false positive in one out of 12 patients without collateral flow (specificity 92%, 95% CI 59-100%). For the posterior communicating artery, sensitivity was 11/14 (79%, 95% CI 49-95%) and specificity was 15/16 (94%, 95% CI 70-100%). Echo-enhanced TCCD enables to study collateral blood flow through the communicating arteries of the circle of Willis with high sensitivity and specificity in patients with obstructions of the internal carotid artery and limited acoustic bone windows.

Aged↗
PubMed2001

Treatment of acute ischemic stroke with the low-molecular-weight heparin certoparin: results of the TOPAS trial. Therapy of Patients With Acute Stroke (TOPAS) Investigators.

BACKGROUND AND PURPOSE: To study the safety and efficacy of the low-molecular-weight heparin certoparin, we performed a randomized, double-blind, dose-finding multicenter trial in patients with acute ischemic stroke (Therapy of Patients With Acute Stroke [TOPAS]). METHODS: We randomized 404 patients to 4 treatment groups within 12 hours of stroke onset: 3000 U anti-factor Xa (aXa) certoparin once daily (treatment group 1); 3000 U aXa twice daily (group 2); 5000 U aXa twice daily (group 3); and 8000 U aXa twice daily (group 4). The primary efficacy variable was the proportion of patients reaching a favorable functional outcome (Barthel Index >/=90 points) at 3 months. CT was performed at trial entry, after 7 days, and on clinical deterioration. RESULTS: The proportion of patients with Barthel Index >/=90 was not different between treatment arms (61.5%, 60.8%, 63.3%, and 56.3% in the 4 groups, respectively; intent-to-treat population). European Stroke Scale scores improved in all treatment groups within the first 14 days to a similar extent. During the follow-up of 6 months, percentages of patients with recurrent stroke/transient ischemic attack were 11.0%, 5.9%, 9.7%, and 13.0% in the 4 groups, respectively. Overall mortality was only 7.4%. Two parenchymal cerebral hematomas and 1 extracranial bleeding episode occurred in treatment group 1 versus 1 and 0 in group 2, 2 and 0 in group 3, and 4 and 5 in group 4, respectively. During certoparin treatment, 1 deep vein thrombosis but no pulmonary embolism was observed. CONCLUSIONS: Dose increase of certoparin up to 8000 U aXa twice daily did not improve the functional outcome of patients with ischemic stroke. Severe bleeding tended to be more frequent in the highest dose group only.

Adolescent↗
PubMed2001

Hemorrhagic transformation of ischemic brain tissue: asymptomatic or symptomatic?

BACKGROUND AND PURPOSE: The term symptomatic hemorrhage secondary to ischemic stroke implies a clear causal relationship between clinical deterioration and hemorrhagic transformation (HT) regardless of the type of HT. The aim of this study was to assess which type of HT independently affects clinical outcome. METHODS: We used the data set of the European Cooperative Acute Stroke Study (ECASS) II for a post hoc analysis. All patients had a control CT scan after 24 to 96 hours or earlier in case of rapid and severe clinical deterioration. HT was categorized according to radiological criteria: hemorrhagic infarction type 1 and type 2 and parenchymal hematoma type 1 and type 2. The clinical course was prospectively documented with the National Institutes of Health Stroke Scale and the modified Rankin Scale: The independent risk of each type of HT was calculated for clinical deterioration at 24 hours and disability and death at 3 months after stroke onset and adjusted for possible confounding factors such as age, severity of stroke syndrome at baseline, and extent of the ischemic lesion on the initial CT. RESULTS: Compared with absence of HT, only parenchymal hematoma type 2 was associated with an increased risk for deterioration at 24 hours after stroke onset (adjusted odds ratio, 18; 95% CI, 6 to 56) and for death at 3 months (adjusted odds ratio, 11; 95% CI, 3.7 to 36). All other types of HT did not independently increase the risk of late deterioration. CONCLUSIONS: Only parenchymal hematoma type 2 independently causes clinical deterioration and impairs prognosis. It has a distinct radiological feature: it is a dense homogeneous hematoma >30% of the ischemic lesion volume with significant space-occupying effect.

Age Factors↗
PubMed2000

Identification of lacunar infarcts before thrombolysis in the ECASS I study.

BACKGROUND: The identification of lacunar infarcts before thrombolysis would make it possible either to exclude them from treatment or to show that they also may benefit from it. OBJECTIVE: To determine whether clinical presentation or early CT findings of patients enrolled in the first European Cooperative Acute Stroke Study (ECASS I) trial would identify lacunar infarcts before treatment. METHODS: Predictive values, sensitivity, specificity, and accuracy of clinical presentation as pure motor hemiparesis (PMH) or sensorimotor stroke (SMS) syndromes and of baseline CT findings in predicting lacunar infarcts were calculated in the ECASS I patients. RESULTS: Of 514 patients, 44 placebo (17%) and 44 recombinant tissue plasminogen activator (rt-PA) (18%) patients had PMH/SMS involving at least two of three areas. Thirty-one placebo (12%) and 32 rt-PA (13%) patients had PMH/SMS involving three areas. The 7-day CT was compatible with a lacunar infarct in 32 placebo (12%) and 44 rt-PA (18%) patients. PMH/SMS involving at least two areas had a positive predictive value of 30% both in placebo and rt-PA patients, whereas positive predictive values of the involvement of three areas were 23% and 31%. Those of absence of early CT signs were 21% and 30%, and those of leukoaraiosis or previous lacunar infarcts were 21% and 23%. Positive predictive values of PMH/SMS involving at least two areas combined with absence of early CT signs were 36% in placebo and 33% in t-PA patients, and those of PMH/SMS plus leukoaraiosis or previous lacunes were 28% and 7%, respectively. CONCLUSIONS: In the ECASS I trial, lacunar infarcts were not recognizable on clinical grounds, and early CT findings, alone or in combination with the clinical picture, added poorly to the differential diagnosis.

Cerebral Infarction↗
PubMed2000

Functional recovery despite prolonged bilateral loss of somatosensory evoked potentials: report on two patients.

A bilateral loss of short latency somatosensory evoked potentials (SSEPs) after head trauma or non-traumatic brain damage is normally associated with a deleterious neurological outcome. An adequate recovery in reported in two deeply comatose patients with head trauma or severe hypertensive encephalopathy despite prolonged bilateral loss of SSEPs over days, found in repeated recordings. Hence, a bilateral loss of SSEPs should not be considered alone for prediction of outcome in cerebral injury.

Adult↗
PubMed2000

Early x-ray hypoattenuation of brain parenchyma indicates extended critical hypoperfusion in acute stroke.

BACKGROUND AND PURPOSE: The presence of early x-ray hypoattenuation is an important selection criterion for thrombolytic therapy. However, knowledge about the pathophysiological constellation reflected by this hypoattenuation is lacking. Our objective was to study the relationship between the presence of early CT hypoattenuation and the volumes of critical cortical hypoperfusion. METHODS: In 32 patients with acute ischemic stroke, CT was performed 20 to 170 minutes (mean, 94 minutes) after symptom onset, and [(15)O]H(2)O-PET 20 to 120 minutes (mean, 67 minutes) later. CTs were scrutinized for the presence of hypoattenuation. On the PET scans, the volumes of critical cortical hypoperfusion were assessed. RESULTS: CT hypoattenuation was present in 18 patients (56%), all of whom had critical cortical hypoperfusion and developed infarction. Of the 14 patients with normal CTs, critical hypoperfusion was found in 6, and 7 developed infarction. The mean volumes of critically hypoperfused tissue differed significantly (P=0.0001, Wilcoxon test) between the CT normal (mean 13.9 cm(3), range 0 to 71 cm(3)) and the CT abnormal (mean 116.3 cm(3), range 4 to 389 cm(3)) groups. CONCLUSIONS: Early presence of hypoattenuation is indicative of extended volumes of critically hypoperfused cortical tissue. The extent of hypoperfusion may exceed that of hypoattenuation, and some of that tissue might still be salvageable.

Acute Disease↗