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Biomedical subjects

H Mattle

Publications and source records attributed to H Mattle.

At least 19 recordsLinked to original sources
PubMed2004

Locally induced hypothermia for treatment of acute ischaemic stroke: a physical feasibility study.

During the treatment of stroke by local intra-arterial thrombolysis (LIT) it is frequently possible to pass the blood clot with a micro-catheter, allowing perfusion of brain tissue distally to the occlusion. This possibility allows for new early treatments of ischaemic brain tissue, even before the blood clot has been removed. One potential new approach to preserve brain tissue at risk may be locally induced endovascular hypothermia. Physical parameters such as the required micro-catheter input pressure, output velocity and flow rates, and a heat exchange model, applicable in the case of a micro-catheter placed within a guiding catheter, are presented. Also, a simple cerebral temperature model is derived that models the temperature response of the brain to the perfusion with coolant fluids. Based on this model, an expression has been derived for the time needed to reach a certain cerebral target temperature. Experimental in vitro measurements are presented that confirm the usability of standard commercially available micro-catheters to induce local hypothermia of the brain. If applied in vivo, the model predicts a local cooling rate of ischaemic brain tissue of 300 g of approximately 1 degrees C in 1 min, which is up to a factor 30-times faster than the time-consuming systemic hypothermia via the skin. Systemic body temperature is only minimally affected by application of local hypothermia, thus avoiding many limitations and complications known in systemic hypothermia.

Algorithms↗
PubMed2004

Escalating immunotherapy of multiple sclerosis--new aspects and practical application.

Recent clinical studies in multiple sclerosis (MS) provide new data on the treatment of clinically isolated syndromes, on secondary progression, on direct comparison of immunomodulatory treatments and on dosing issues. All these studies have important implications for the optimized care of MS patients. The multiple sclerosis therapy consensus group (MSTCG) critically evaluated the available data and provides recommendations for the application of immunoprophylactic therapies. Initiation of treatment after the first relapse may be indicated if there is clear evidence on MRI for subclinical dissemination of disease. Recent trials show that the efficacy of interferon beta treatment is more likely if patients in the secondary progressive phase of the disease still have superimposed bouts or other indicators of inflammatory disease activity than without having them. There are now data available, which suggest a possible dose-effect relation for recombinant beta-interferons. These studies have to be interpreted with caution, as some potentially important issues in the design of these studies (e. g. maintenance of blinding in the clinical part of the study) were not adequately addressed. A meta-analysis of selected interferon trials has been published challenging the value of recombinant IFN beta in MS. The pitfalls of that report are discussed in the present review as are other issues relevant to treatment including the new definition of MS, the problem of treatment failure and the impact of cost-effectiveness analyses. The MSTCG panel recommends that the new diagnostic criteria proposed by McDonald et al. should be applied if immunoprophylactic treatment is being considered. The use of standardized clinical documentation is now generally proposed to facilitate the systematic evaluation of individual patients over time and to allow retrospective evaluations in different patient cohorts. This in turn may help in formulating recommendations for the application of innovative products to patients and to health care providers. Moreover, in long-term treated patients, secondary treatment failure should be identified by pre-planned follow-up examinations, and other treatment options should then be considered.

Clinical Trials as Topic↗
PubMed2004

Percutaneous closure of patent foramen ovale: impact of device design on safety and efficacy.

OBJECTIVE: To compare the safety and efficacy of percutaneous closure of patent foramen ovale (PFO) with the Amplatzer PFO occluder (Amplatzer) or the PFO STAR device (STAR) in patients with presumed paradoxical embolism. METHODS: Implantation characteristics, procedural complications, residual shunt, and recurrence of thromboembolic events were recorded prospectively in 100 consecutive patients undergoing percutaneous PFO closure with the STAR (n = 50) or Amplatzer (n = 50) devices between 1998 and 2001. The study was not randomised. Device implantation was successful in all cases. RESULTS: There were more procedural complications in the STAR than in the Amplatzer group (8/50 v 1/50, p = 0.01). More than one device placement attempt was an independent predictor of procedural complications (odds ratio (OR) 8.5, 95% confidence interval (CI) 1.3 to 55.8; p = 0.03). A residual shunt six months after PFO closure, assessed by transoesophageal contrast echocardiography, occurred more often in the STAR than the Amplatzer group (17/50 v 3/50, p = 0.004), and was predicted in the STAR group by the use of a device with a 5 mm as opposed to a 3 mm disc connector (OR 6.1, 95% CI 1.1 to 34.0; p = 0.04). The actuarial risk of recurrent thromboembolic events after 3.5 years was 16.8% (95% CI 7.6% to 34.6%) in the STAR and 2.7% (95% CI 0.4% to 17.7%) in the Amplatzer group after three years (p = 0.08). CONCLUSIONS: Percutaneous PFO closure with the Amplatzer PFO occluder had fewer procedural complications and was more likely to be complete than with the STAR device. These findings underline the importance of device design for successful percutaneous PFO closure.

Balloon Occlusion↗
PubMed2003

[Stents in the treatment of supraaortic vessel stenosis].

We describe and discuss our experience of more than 500 endovascular procedures for revascularisation of acute or chronic occlusion and stenosis of supraaortic vessels using stents in 171 cases. Whereas endovascular treatment of the innominate, subclavian and vertebral arteries are routinely used in atherosclerotic occlusive lesions, carotid stenting is currently being investigated as an alternative treatment to carotid endarterectomy and seems to offer a less invasive, less traumatic and less cost expensive alternative to achieve the goal to prevent stroke. In a subgroup of high surgical risk patients carotid artery stenting with simultaneous embolic protection of the cerebral blood flow by filter systems was even superior to the endarterectomy-treated patients in a prospective, randomized multi-center study (SAPPHIRE): at 30-day follow up the major event rate for the stented group of 156 patients was 5.8% versus 12.6 for the 151 endarterectomy-treated patients.

Angiography↗
PubMed2000

[Results and role of carotid endarterectomy].

BACKGROUND: The indications for carotid endarterectomy have been defined on the basis of several large prospective randomised trials. Today this operation is widely performed as primary and secondary stroke prevention in patients with high grade carotid artery stenosis. Permanent quality control of the surgical results is mandatory to ensure optimal stroke prevention and further reduce perioperative complications. METHODS: In this retrospective study we analyse the surgical results of 272 consecutive carotid endarterectomies performed in 260 patients with special emphasis on the prevention of intraoperative brain ischaemia. Patients were operated on in general anaesthesia and moderate hypothermia. Before clamping the arteries at the neck, a fast-acting barbiturate or propofol was administered intravenously to obtain burst suppression on the EEG. Transcranial Doppler sonography allowed continuous intraoperative monitoring of brain perfusion and detection of emboli. Intraoperative shunting was performed only when the collateral circulation was insufficient. RESULTS: The postoperative course was uneventful in 249 endarterectomies (91.5%). The internal carotid artery was sonographically recanalised at hospital discharge and at 6-week follow-up in all 249 cases. Ischaemic cerebral complications were observed in 7 patients (2.6%): minor reversible brain ischaemia in 4 (1.5%), and major brain ischaemia with infarction in 3 (1.1%). Three patients died in the perioperative period, representing a mortality rate of 1.1% in this series. The overall combined stroke and death rate was 3.7%. The combined major stroke and death rate was 2.2%. Various non cerebral complications occurred in 13 patients (4.8%). CONCLUSIONS: These results confirm that endarterectomy is a safe and efficient treatment for atherosclerotic carotid stenosis at the neck. Very low complication rates can be attained by non-invasive diagnostic methods combined with intraoperative monitoring of cerebral blood flow velocity. New upcoming endovascular therapies such as percutaneous angioplasty and stenting need to be compared with these current surgical results with regard not only to perioperative morbidity and mortality but also patency rate, restenosis, and intracerebral blood flow restoration.

Adult↗
PubMed1999

The site of atheromatosis in the subclavian and vertebral arteries and its implication for angioplasty.

We analysed the site of plaques and stenoses in the subclavian and vertebral arteries, to improve the safety of percutaneous transluminal angioplasty (PTA) in high-risk patients. These lesions were assessed on arteriograms of 35 patients with stenoses and occlusions of the subclavian and vertebral arteries; the degree of stenoses was measured. Of 19 subclavian artery stenoses 17 (89%) were in the segment proximal to the vertebral artery; 30 (79%) of 38 vertebral artery stenoses were on the medial wall. With this knowledge, a double-balloon technique using a simultaneous transbrachial and transfemoral approach for angioplasty of high-risk subclavian or combined subclavian and vertebral artery stenoses and occlusions was used successfully in seven patients. This new technique may broaden the endovascular therapeutic possibilities in the rare but dangerous situation where plaque extends directly from the stenotic subclavian artery into the origin of the vertebral artery.

Aged↗
PubMed1998

Local intra-arterial thrombolysis in acute ischemic stroke.

BACKGROUND AND PURPOSE: We performed a retrospective analysis of the prognostic factors in patients treated with local intra-arterial thrombolysis (LIT). The purpose of this study was to evaluate the safety and efficacy of LIT using urokinase in patients with acute ischemic stroke of the anterior or posterior circulation and to determine the influence of clinical and radiological parameters on outcome. METHODS: Forty-three patients were treated with LIT using urokinase (median dose, 0.75x10(6) IU). The median National Institutes of Health Stroke Scale (NIHSS) score at hospital admission was 18 (range, 9 to 36). Nine patients had occlusions of the internal carotid artery (ICA), 23 of the middle cerebral artery (MCA), 1 of the anterior cerebral artery, and 10 of the basilar artery (BA). Outcome was assessed after 3 months and classified as good for Rankin Scale (RS) scores of 0 to 3 and poor for RS scores of 4 or 5 and death. RESULTS: Nine patients (21%) recovered to RS scores 0 or 1, 17 (40%) to scores of 2 or 3, and 7 (16%) to scores of 4 or 5. Ten patients (23%) died. Outcome was good in 17 patients (80%) with MCA occlusions, in 3 patients (33%) with ICA, and in 5 patients (50%) with BA occlusions. Good outcome was associated with an initial NIHSS score of <20 (P<0.001), improvement by 4 or more points on NIHSS score within 24 hours (P=0.001), and vessel recanalization (P=0.02). Recanalization was more likely if LIT was started within 4 hours (P=0.01). Symptomatic cerebral hemorrhage occurred in 2 patients (4.7%). CONCLUSIONS: LIT was most efficacious in patients with MCA and BA occlusions when the initial NIHSS score was less than 20 and when treated within 4 hours. It is of limited value in patients with distal ICA occlusions.

Acute Disease↗
PubMed1997

Medial medullary stroke: report of seven patients and review of the literature.

Medial medullary infarctions (MMI) were reported in less than 40 patients with satisfactory clinicotopographic documentation. We studied seven patients with MRI-proven acute MMI seen in two neurologic departments over a 5-year period (1990-1994). MMI represented less than 1% of ischemic strokes in the posterior circulation. Five patients had an infarction above the pyramidal decussation. All patients had contralateral hemiparesis and lemniscal sensory loss, accompanied by ipsilateral lingual palsy (Dejerine's syndrome) in three. Two patients had infarction below the pyramidal decussation, with ipsilateral hemiparesis and lemniscal sensory loss. Accompanying symptoms and signs of MMI were vertigo and nausea (n = 5), mild ipsi- or contralateral decrease in pain sensation (n = 6), headache (n = 4), ipsilateral limb ataxia (n = 6), contralateral truncal lateropulsion (n = 5), mild ipsilateral ptosis (n = 4), nystagmus (n = 4), dysarthria (n = 3), and somnolence (n = 2). Presumed causes of MMI were stenosis, occlusion or dissection of the ipsilateral vertebral artery (n = 5), and cardioembolism (n = 1). Outcome at 3 months was favorable in five patients. In conclusion, the clinical features of MMI are more heterogeneous than commonly thought, whereas its etiology seems fairly constant (vertebral artery disease).

Adult↗
PubMed1992

[Neuro-Behçet's syndrome: encephalitis and cerebral venous thrombosis--clinical aspects and neuroradiology of 5 cases].

The value of brain CT-scan, magnetic resonance imaging (MRI) and angiography for diagnosis, differential diagnosis and follow up in Neuro-Behçet-Syndrome is assessed in 5 cases. Three of the patients presented with clinical signs of encephalitis. Further investigations led to the diagnosis of Behçet-Syndrome. CT-scan was negative in two of these cases, but MRI showed multiple, predominantly periventricular lesions with high signal intensity on T2-weighted spin-echo images in all three. Clinical symptoms improved with steroid and chlorambucil therapy in all three cases. In two patients the MRI-lesions resolved at least partially after 1.5 and 3 years of treatment respectively. In one patient the initial MRI-findings were still present after 7 months of treatment. The other two patients presented with headache, papilledema and increased CSF-pressure. The cause was superior sagittal sinus thrombosis, confirmed by angiography in both cases. Additional symptoms appeared later and led to the diagnosis of Behçet syndrome. One patient died of pulmonary aneurysms 28 months after the diagnosis had been established. The course of disease of the remaining patient is so far favorable.

Adult↗
PubMed1991

Middle cerebral artery: determination of flow velocities with MR angiography.

A magnetic resonance (MR) angiographic technique for noninvasive measurement of flow velocities in the intracranial cerebral arteries was studied. Velocity measurements were made in a phantom and in the middle cerebral artery of six volunteers. Velocities were assessed in the volunteers before, during, and after finger movement. Average values for mean maximal velocities determined with MR angiography were 69.8 cm/sec before, 77.2 cm/sec during, and 69.6 cm/sec after finger movement. Correlations between values obtained with MR angiography and transcranial Doppler (TCD) sonography were r = .86 and P = .0001 for values obtained at rest and r = .84 and P = .0001 for values obtained during finger movement. The velocity increase during finger movement compared with that at rest was 11% for MR angiography and 11.3% for TCD sonography. Values measured with TCD sonography, however, were less than those measured with MR angiography (P = .001). The results show the feasibility of measuring flow velocities in intracranial arteries with MR angiography.

Adult↗
PubMed1990

[Magnetic resonance angiography. Work in progress].

Rapid progress has been made in the development and clinical application of magnetic resonance (MR) techniques for creating angiogram-like images of blood vessels. Combinations of techniques such as gradient-echo pulse sequences and flow compensation (bright blood imaging) or presaturation (black blood imaging) permit the signal intensities of moving spins to be altered, so as to generate contrast between flowing blood and stationary tissues. Postprocessing of the images allows the creation of projection angiograms, which show the vasculature in a large slice of the body. Preliminary studies suggest a variety of potential clinical applications, including intracranial arteriovenous malformations and aneurysms, carotid artery disease, portal hypertension, renal artery stenosis, peripheral arterial disease and venous thrombosis. At present, MR angiography is not directly competitive with conventional contrast angiography because of lower spatial resolution and loss of signal from flow turbulence and from slow flow. Nonetheless, it is proving to be a useful clinical tool for the investigation of vascular pathology involving the head and body.

Angiography↗
PubMed1990

Flow quantification in the superior sagittal sinus using magnetic resonance.

To date, the intracerebral veins and venous sinuses have not been amenable to noninvasive study. We describe a magnetic resonance (MR) technique using "bolus tracking" for rapid imaging and measurement of cerebral venous flow. We specifically applied the technique to the superior sagittal sinus, but it can be used for evaluation of other cerebral venous structures. In 10 healthy subjects and 21 patients referred for MR brain studies, mean flow was 420 ml/min. There was a significant inverse correlation between blood flow and age. There were dynamic changes in cerebral blood flow (CBF) during hyperventilation and hypercapnia. Since the cerebral cortex drains almost exclusively to the superior sagittal sinus, these flow measurements represent an index of global CBF. MR flow quantification provides a new means for assessing dynamic changes in CBF, and may prove useful for monitoring the effects of various disease processes and pharmaceutical agents on CBF.

Adolescent↗
PubMed1990

[Extreme lateral lumbar intervertebral disk displacement. Incidence, symptoms and therapy].

Upper lumbar nerve root compression or a femoralgia is often caused by extreme lateral lumbar disc herniation. This type of lumbar disc herniation compresses the nerve root inside or laterally to the intervertebral canal, while mediolateral disc herniations squeeze it in the lateral recess. Pain radiating obliquely over the thigh is the dominant clinical symptom. Bending the body to the ipsilateral side usually increases the pain. When neurologic signs are present, motor deficits tend to be more prominent than sensory and the deficits never affect more than one nerve root. Most frequently a weakness of knee extension occurs.

Humans↗
PubMed1989

[Diagnosis, therapy and prevention of cerebrovascular diseases. 2. Therapy and prevention].

Elimination of vascular risk factors is of paramount importance in preventing stroke. Once a vascular pathology is present, various surgical and medical measures must be considered in order to lower the risk of cerebrovascular accident. When infarction has occurred, the therapeutic possibilities are limited and aim at reducing the size of a stroke. The authors review current issues in stroke prevention and treatment.

Anticoagulants↗
PubMed1989

[Neurofibrosarcomas in neurofibromatosis 1].

Between 1983 and 1987 three patients (mean age 31 years) with neurofibrosarcoma were seen among 22 with von Recklinghausen neurofibromatosis (NF-1) at the Department of Neurology, University of Berne, Switzerland. There was an average interval of 14 months between onset of symptoms and treatment. The first presenting sign was a rapidly enlarging mass or unusual persistent pain. The occurrence of either sign, in the known presence of NF-1, should lead to immediate neuroradiological investigation. The mean survival time of the three patients was 37 months. Only early diagnosis provides any chance of curative treatment.

Adult↗
PubMed1989

Anticoagulation-related intracranial extracerebral haemorrhage.

From January 1981 to June 1986 116 patients with anticoagulation-related intracranial haemorrhage were referred to hospital. Seventy six of these haemorrhages were extracerebral, 69 were in the subdural and seven in the subarachnoid space. No epidural haemorrhages were identified. Compared with non-anticoagulation-related haematomas, the risk of haemorrhage was calculated to be increased fourfold in men and thirteenfold in women. An acute subdural haematoma, mostly due to contusion, was more frequently accompanied by an additional intracerebral haematoma than a chronic subdural haematoma. Trauma was a more important factor in acute subdural haematomas than in chronic. Almost half of the patients (48%) had a history of hypertension, more than a third (35%) had heart disease and about one fifth (18%) were diabetic. Headache was the most frequent initial symptom. Later decreased level of consciousness and focal neurological signs exceeded the frequency of headache. Three patients with subarachnoid haemorrhage and nine patients with acute subdural haematomas died, while those with chronic subdural haematomas all survived and had at the most mild, non-disabling sequelae. Myocardial infarction (22%), pulmonary embolism (20%), and arterial disease (20%) were the most frequent reasons for anticoagulant treatment. Critical review based on established criteria for anticoagulation treatment suggests there was no medical reason to treat a third of these patients. The single most useful measure that could be taken to reduce the risk of anticoagulation-induced intracranial haemorrhage would be to identify patients who are being unnecessarily treated and to discontinue anticoagulants.

Aged↗