Biomedical subjects

A Algra

Publications and source records attributed to A Algra.

At least 145 records · Page 8Linked to original sources

PubMed1999

Initial loss of consciousness and risk of delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage.

BACKGROUND AND PURPOSE: Delayed cerebral ischemia (DCI) is a major cause of death and disability in patients with aneurysmal subarachnoid hemorrhage. We studied the prognostic value for DCI of 2 factors: the duration of unconsciousness after the hemorrhage and the presence of risk factors for atherosclerosis. METHODS: In 125 consecutive patients admitted within 4 days after hemorrhage, we assessed the presence and duration of unconsciousness after the hemorrhage, the neurological condition on admission, the amount of subarachnoid blood, the size of the ventricles, and a history of smoking, hypertension, stroke, or myocardial infarction. The relationship between these variables and the development of DCI was analyzed by means of the Cox proportional hazards model. RESULTS: The univariate hazard ratio (HR) for the development of DCI in patients who had lost consciousness for >1 hour was 6.0 (95% CI 3.0 to 12.0) compared with patients who had no loss or a <1-hour loss of consciousness. The presence of any risk factor for atherosclerosis yielded an HR of 1.4 (95% CI 0.6 to 3.5). The HR for unconsciousness remained essentially the same after adjustment for other risk factors for DCI. The HR for a poor World Federation of Neurological Surgeons score (grade IV or V) on admission was 2.9 (95% CI 1.5 to 5. 5); that for a large amount of subarachnoid blood on CT was 3.4 (95% CI 1.6 to 7.3). CONCLUSIONS: The duration of unconsciousness after subarachnoid hemorrhage is a strong predictor for the occurrence of DCI. This observation may contribute to a better understanding of the pathogenesis of DCI and increased attention for patients at risk.

Arteriosclerosis↗

PubMed1999

Treatment of intracranial aneurysms by embolization with coils: a systematic review.

BACKGROUND: Embolization with coils is increasingly used for the treatment of intracranial aneurysms. To assess the percentage of complications, the percentage of aneurysm occlusion, and the short-term outcome, we performed a systematic review of studies on embolization with controlled detachable or pushable coils. SUMMARY OF REVIEW: To find studies on embolization with coils, we performed a MEDLINE search from January 1990 to March 1997, checked all reference lists of the studies found, performed a Science Citation Index search on Guglielmi, and hand searched recent volumes of 25 journals. Two authors independently extracted data by means of a standardized data extraction form from 48 eligible studies totalling 1383 patients. Permanent complications of embolization with controlled detachable coils occurred in 46 of 1256 patients (3.7%; 95% CI, 2.7% to 4.9%); 400 of 744 aneurysms (54%; 95% CI, 50% to 57%) were completely occluded. By means of weighted linear regression, no relation between baseline characteristics and outcome measurements was found. The results in the prespecified subgroups of patients with a ruptured aneurysm, an unruptured aneurysm, or a basilar bifurcation aneurysm were essentially the same as the overall results. CONCLUSIONS: Short-term results indicate that embolization with coils is a reasonably safe treatment for patients with an unruptured aneurysm and for patients with aneurysmal subarachnoid hemorrhage. The effectiveness in terms of complete occlusion of the aneurysm is moderate. Randomized trials are warranted to compare surgical clipping with embolization with coils.

Adolescent↗

PubMed1999

Incidence and determinants of mortality and cardiovascular events in diabetes mellitus: a meta-analysis.

Patients with diabetes mellitus are at increased risk of developing atherosclerotic disease. The extent of this additional risk and its determinants are not well known, but this information is needed for sample-size estimations in intervention studies. Therefore, a meta-analysis of epidemiologic studies on this subject was performed. Medline was searched from 1966 onwards, including the reference lists of all relevant publications. A total of 27 prospective follow-up studies in the English language that allowed calculation of the unadjusted incidence of one of the predefined outcome events were included. The influence of age, sex, type of diabetes, duration of diabetes, year of study, HbA1c, cholesterol level, blood pressure and smoking on these incidences was studied by means of univariate Poisson regression analysis. Overall total mortality was 2.9% per year (95% CI 2.8-3.0; 27 studies), and for death from all vascular causes was 1.4% per year (95% CI 1.3-1.4; 16 studies). Only two studies were found that reported on the incidence of the composite outcome 'event death from all vascular causes, non-fatal myocardial infarction, or non-fatal stroke'. In univariate analysis, age, year of study, total cholesterol and systolic blood pressure were positively related to total mortality and death from all vascular causes. After adjustment for age, or limiting the analyses to studies in patients with type 2 diabetes only (n = 11), these relationships remained statistically significant. In conclusion, the overall yearly total mortality in diabetes mellitus is 2.9% and for death from all vascular causes is 1.4%. There are few data on the incidence of composite cardiovascular outcome events.

Cerebrovascular Disorders↗

PubMed1999

MR angiography as a screening tool for intracranial aneurysms: feasibility, test characteristics, and interobserver agreement.

OBJECTIVE: MR angiography may be an appropriate tool to screen for unruptured intracranial aneurysms. Feasibility, test characteristics, and interobserver agreement in evaluation of MR angiograms were assessed by members of the MARS (Magnetic resonance Angiography in Relatives of patients with Subarachnoid hemorrhage) Study Group. SUBJECTS AND METHODS: We screened 626 first-degree relatives of a consecutive series of 193 patients with subarachnoid hemorrhage examined at two institutions. We used MR imaging and MR angiography (three-dimensional time-of-flight imaging at both institutions and additional three-dimensional phase-contrast imaging at one institution). Three observers independently assessed the MR angiograms. Conventional angiography was performed in relatives with possible or definite aneurysms on MR angiography and was considered the standard of reference. RESULTS: Thirty-three aneurysms were found in 25 (4%; 95% confidence interval [CI], 3-6%) of 626 relatives. Thirteen (8%) of 169 relatives who refused screening had MR-related reasons; an additional six persons could not be screened because of contraindications for MR imaging (pregnancy, n = 1; claustrophobia, n = 5). The positive predictive value of MR angiography was 100% (95% CI, 79-100%) for "definite" aneurysms and 58% (95% CI, 28-85%) for "possible" aneurysms. Sensitivity of MR angiography was estimated at 83% (95% CI, 65-94%) and specificity at 97% (95% CI, 94-98%). Interobserver agreement in the evaluation of MR angiograms was poor (kappa < .30), probably because different diagnostic strategies used by individual observers resulted in different use of the assessment category "possible aneurysm." CONCLUSION: MR angiography is a feasible screening tool for detection of intracranial aneurysms. Positive predictive value, sensitivity, and specificity are acceptable when at least two neuroradiologists independently assess MR angiograms.

Adult↗

PubMed1998

Likelihood of underreporting of outlet strut fracture from examination of the Dutch Björk-Shiley CC cohort.

The Dutch Björk-Shiley convexo-concave (BScc) cohort serves as a reference population on the risk of outlet strut fracture and is being used to formulate guidelines for prophylactic replacement. Fractures, however, may be undetected at death. The aim of this study was to quantify the degree of underestimation of strut fracture in the Dutch BScc cohort. Multivariate Cox regression analysis was used to assess the relative and absolute risk of death from different causes within 14 years. The unexplained "excess" mortality among 70 degrees BScc valve recipients was attributed to unreported fatal strut fractures and used to estimate its extent in this group, which then was extrapolated to the 60 degrees BScc valve recipients. For 70 degrees BScc valve recipients, the adjusted hazard ratio for death from all causes except strut fracture was 1.2 (95% confidence interval [CI] 1.0 to 1.5). The 14-year absolute risks for 70 degrees and 60 degrees BScc valve recipients were 44% and 37%, respectively. Among 70 degrees and 60 degrees BScc valve recipients, underreporting of fracture was estimated to be 25% (95% CI 0 to 49) and 26% (95% CI 0 to 52), respectively. Estimates based on sudden death and fatal congestive heart failure yielded essentially the same results. Thus, underreporting of fatal strut fracture in the Dutch BScc cohort is estimated to be approximately 25%. Hence, the risk and lethality of fracture of BScc valves are underestimated and indications for prophylactic replacement should be adjusted accordingly. For example, the advantage of valve replacement in a 40-year-old patient with a 29-mm 60 micro BScc mitral valve would almost double to 0.82 years.

Death, Sudden↗

PubMed1998

[Chronicle of a defective heart valve prosthesis].

The Björk-Shiley convexo-concave (BScc) strut fracture problem is about to enter its third decade. At present, valve carriers still face the risk of outlet strut fracture; a risk which does not seem to decline. The temporising attitude of the manufacturer has led to far more victims than would have been necessary but also the Food and Drug Administration, regulatory agencies outside the US and the medical community share responsibility for this problem.

Confidentiality↗

PubMed1998

[Methylprednisolone in traumatic spinal cord injuries: not proven to be beneficial to the patient at the present time].

Ever since the publication in 1990 in The New England Journal of Medicine of a multicentre, randomised, double-blind, placebo-controlled trial on the efficacy of methylprednisolone (MP) in the treatment of acute, traumatic spinal cord injury, the advice is to administer MP as soon as possible to every patient presenting a traumatic spinal cord injury. This recommendation has been followed throughout the world, especially by traumatologists, and seems to be above criticism. However, the results of most cited studies, which have had a major influence on the treatment of patients with an acute, traumatic spinal cord lesion, show that the improvements in the neurological condition due to MP cannot be translated into a specific improvement in the functional status. Until it has been proven beyond reasonable doubt that MP can play a significant role in the treatment of these patients, we advise that MP should not be administered to a patient with acute, traumatic spinal cord injury, awaiting the results of more quantitative research. Such research is being performed by the Cochrane Brain and Spinal Cord Injury Group.

Emergency Treatment↗

PubMed1998

[The screening for asymptomatic vascular disease and risk factors in high risk patients: current practice].

OBJECTIVE: To assess current practice in screening for asymptomatic vascular disease and risk factors in patients referred with vascular disease or cardiovascular risk factors. DESIGN: Descriptive, retrospective. SETTING: University Hospital Utrecht, Utrecht, the Netherlands. METHOD: By means of the computerized hospital registration system all patients who were referred to the outpatient clinic with carotid stenosis, peripheral artery disease, abdominal aortic aneurysm, diabetes mellitus, hyperlipidaemia or hypertension during one year were identified. By means of the same hospital registration system the frequency of diagnostic tests performed to detect atherosclerosis or risk factors in these patients within a period of 5 months round the first attendance was determined. RESULTS: 372 Patients with a vascular disease and 317 patients with a risk factor were identified. Tests to detect carotid stenosis, peripheral artery disease or an abdominal aortic aneurysm were each performed in less then 6% of all patients except the test for abdominal aortic aneurysm. Tests to detect coronary artery disease were performed in about 50% of all patients. Tests to detect diabetes mellitus were performed in 35% of the patients with vascular disease and in 81% of the patients presenting with hyperlipidaemia or hypertension. Tests to detect hyperlipidaemia were performed in 18% of the patients with a vascular disease and in 76% of the patients with diabetes or hypertension. CONCLUSION: The results of this study suggest that in current practice patients referred for vascular disease or cardiovascular risk factors are infrequently screened for asymptomatic macrovascular disease and risk factors.

Adult↗

PubMed1998

[Secondary prevention following cerebral ischemia: is monotherapy with acetylsalicylic acid still first choice?].

Acetylsalicylic acid (ASA) alone (at least 30 mg per day) in post-cerebral ischaemia patients reduces the relative risk of further vascular events by 13% compared with placebo. A meta-analysis of all studies shows that the combination of ASA with dipyridamole reduces the relative risk by 16% (95% confidence interval: 5-26%) compared with ASA alone, but confirmation by a major trial appears desirable, because of discrepant results of a recent trial and 4 previous ones. Clopidogrel might reduce the risk by 7% compared with ASA alone, but this drug is expected to be expensive. Anticoagulation therapy with an international normalized ratio (INR) of 2.0-4.0 is particularly efficacious for secondary prevention in patients with atrial fibrillation, but anticoagulation therapy with an INR of 3.0-4.5 is not safe in secondary prevention of cerebral ischaemia of presumed arterial origin. Finally, not all atherosclerotic vascular diseases are identical from the therapeutic point of view; the effect of treatment depends in part on the clinical manifestation form.

Anticoagulants↗

PubMed1998

[Prevention of vascular complications following cerebral ischemia of arterial origin; the ESPRIT trial: mild anticoagulant therapy, combination treatment with acetylsalicylic acid plus dipyridamole or treatment with acetylsalicylic acid alone?].

The European and Australian Stroke Prevention in Reversible Ischaemia Trial (ESPRIT) is a randomised clinical trial in which patients with cerebral ischaemia of arterial origin will be randomised between oral anticoagulation (international normalized ratio (INR): 2.0-3.0), the combination of acetylsalicylic acid (in any dose between 30 and 325 mg per day) plus dipyridamole (400 mg daily) and acetylsalicylic acid only (in any dose between 30 and 325 mg per day). It is planned to enroll 4500 patients with a mean follow-up of three years. Primary outcome is the composite event of vascular death, stroke, myocardial infarction, or major bleeding complication; outcome assessment will be blinded. ESPRIT is an international, multicentre study in which 60-80 hospitals in the Netherlands and other countries in Europe and Australia will participate.

Adult↗

PubMed1998

Prophylactic replacement of Björk-Shiley convexo-concave valves at risk of strut fracture. Björk-Shiley Study Group.

OBJECTIVE: Prophylactic replacement of Björk-Shiley convexo-concave valves (Shiley, Inc., Irvine, Calif.) has been advised for selected groups of patients. If prophylactic replacement is considered, risks of postoperative morbidity and mortality have to be weighed against benefits of replacement. Here we report the results of prophylactic replacement of Björk-Shiley convexo-concave valves at risk of strut fracture in The Netherlands. METHODS: We reviewed medical records of 36 patients undergoing prophylactic replacement of their Björk-Shiley convexo-concave valves before August 1995. Replacement was judged to be prophylactic if the risk of strut fracture outweighed that of death from reoperation, or the patient wished to have the valve replaced although it was not recommended. The procedure was also considered to be prophylactic if a concomitant pathologic condition, not likely to require cardiac surgery in the near future, was present or if preoperative examination revealed an unexpected cardiac pathologic condition. RESULTS: Twenty-two 70-degree and 16 60-degree Björk-Shiley convexo-concave valves and one spherical valve were replaced (25 aortic and 14 mitral, including three double-valve replacements). Early mortality was 2.8% (1/36) (exact 95% confidence interval [CI] 0.1 to 14.5). Mean follow-up was 33 months. One- and 3-year survivals were 94% (95% CI 79% to 99%) and 91% (95% CI 74% to 97%), respectively. All three deaths were sudden. CONCLUSIONS: If special care is taken in selecting patients, the risk of prophylactic replacement is comparable to that of primary valve replacement. More data are needed to assess whether the risk of sudden death is possibly increased.

Adult↗

PubMed1998

Effect of timing of blood pressure measurement in the assessment of arterial stiffness: the SMART Study.

In the assessment of arterial stiffness, pulse pressure is measured. Presently, there is no consensus on how pulse pressure should be measured. Distensibility of the left and right common carotid arteries was measured noninvasively in 224 patients participating in the Second Manifestations of ARTerial disease (SMART) study. Blood pressure was recorded every 4 min, using a semiautomatic oscillometric device. Distensibility coefficients (DC) were calculated with pulse pressure obtained as an average of (A) all measurements during the session; (B) the second, third, and fourth measurement; (C) measurements before and after distensibility assessment; and (D) three measurements nearest to distensibility assessment. Associations of cardiovascular risk factors with the four calculated DCs were evaluated with linear regression analysis. DC estimates were slightly more precise with methods A and B than with C or D. The magnitude of the associations showed a slight trend to higher precision for methods A and B. Pulse pressures obtained as an average of all or the second, third, and fourth blood pressure measurements during an arterial stiffness measurement session yield slightly more precise estimates of DC. However, the differences between the methods are small; therefore, we suggest that pragmatic arguments dominate the choice between the methods.

Blood Pressure Determination↗

PubMed1998

Transcranial cerebral oximetry during carotid endarterectomy: agreement between frontal and lateral probe measurements as compared with an electroencephalogram.

OBJECTIVE: Transcranial cerebral oximetry, which is considered a novel technique, was evaluated during carotid endarterectomy. For practical reasons, the use of a single probe attached to the forehead and overlying the territory of the anterior cerebral artery is recommended. Other monitoring systems (transcranial Doppler, electroencephalograms (EEG)) focus more on the territory of the middle cerebral artery. The aim of this study was to evaluate whether a probe in the frontal area is as representative for monitoring cerebral ischaemia during carotid cross-clamping as a probe in the lateral area. DESIGN: Clinical prospective study. MATERIALS: Sixty patients who underwent carotid endarterectomy were studied with continuous and simultaneous EEG and transcranial cerebral oximetry. Forty-three patients (72%) simultaneously underwent frontal and lateral transcranial cerebral oximetry. The lateral probe was only used in 17 patients. METHODS: The percentage decrease of transcranial cerebral oximetry was calculated during cross-clamping. Using the EEG findings as the gold standard in order to detect cerebral ischaemia during carotid cross-clamping, the relationship with transcranial cerebral oximetry was described in terms of sensitivity, specificity and the area under the curve in a receiver operating characteristic curve. RESULTS: The 95% confidence interval of the area under the curve of the receiver operating characteristic of the lateral probe was 0.61-1.00 and that of the frontal probe was 0.65-1.00; therefore there is virtually no difference between the two methods. In 18% of the cases the lateral transcranial cerebral oximetry was hindered by practical failures. CONCLUSION: Considering the lack of additional information and the practical problems experienced with the lateral probe, it was concluded that transcranial cerebral oximetry with a single frontal probe is a practical non-invasive monitoring system and is at least as representative for monitoring cerebral ischaemia during carotid cross-clamping as a lateral probe.

Brain↗

PubMed1998

Reproducibility of measurements of intima-media thickness and distensibility in the common carotid artery.

OBJECTIVE: To assess reproducibility of ultrasonographic measurements of arterial distensibility and intima-media thickness (IMT) in the common carotid arteries. DESIGN: Prospective study. MATERIALS: Measurements of IMT and arterial distensibility were performed on-line in B-mode and M-mode, respectively. Blood pressure was assessed. From the measured variables stiffness indices were derived. METHODS: Twenty-five persons were included in the IMT study, both healthy subjects and patients with atherosclerotic disease. Distensibility was measured in a randomly selected subgroup of 10 persons. All subjects were examined by two different sonographers on the same day and were re-examined after 1 or 2 weeks. RESULTS: When data from both carotid arteries were combined, the interobserver coefficient of variation of IMT was on average 11.7%, of diastolic diameter 3.3% of distension and relative distension 11.8%, of distensibility coefficient 12.3%, and of stiffness parameter beta 19%. Intraobserver variability was slightly lower than interobserver variability. Variability for measurements in the right common carotid artery only was higher than for measurements of both carotid arteries combined. CONCLUSIONS: Our study demonstrates that reproducibility of measurements of IMT and arterial distensibility of the common carotid artery, by B-mode and M-mode ultrasonography respectively, is acceptable when used in large studies.

Aged↗

PubMed1998

Near-infrared reflected spectroscopy and electroencephalography during carotid endarterectomy--in search of a new shunt criterion.

The aim of this clinical study was to evaluate cerebral oximetry with near-infrared reflected spectroscopy (NIRS) as a monitoring system during carotid endarterectomy. The cross-clamping changes of cerebrovascular hemoglobin oxygen saturation (cereb. O2 satn.) were compared with data from a processed EEG analysis. Using the EEG as the gold standard we try to define a new shunt criterion based on near-infrared spectroscopy. 102 patients were studied. During cross-clamping the percentual decrease of cereb. O2 satn. was calculated. The relation between EEG and cereb. O2 satn. is described in terms of sensitivity and specificity, and is graphically shown in a Receiver Operator Characteristic (ROC) curve. At a cut-off value of 5% decrease or more for the cereb. O2 satn., a sensitivity of 100% was found. However, the specificity was only 44%. Higher cut-off values resulted in a gradual increase of the specificity at the expense of a significant decrease of the sensitivity. In conclusion, improved validation and calibration techniques are necessary before this technique may be used for relevant assessment of cerebral oxygenation during carotid surgery. In particular, in order to define a new shunt criterion, the focal aspect of this new technique is probably one of the limitations.

Arteriovenous Shunt, Surgical↗

PubMed1998

Mayo and NINDS scales for assessment of tendon reflexes: between observer agreement and implications for communication.

The purpose of this study was to assess the between observer reliability of two standard notation scales for grading tendon reflexes, The Mayo Clinic scale and the NINDS scale. In a university department of neurology two or three physicians judged the biceps, triceps, knee, and ankle tendon reflexes in two groups of 50 patients using either scale. The interobserver agreement was assessed by means of kappa statistics. The agreement among doctors was never better than "fair" for both scales (highest kappa value 0.35). A verbal description rather than a codified scale may improve communication among doctors.

Adult↗

PubMed1998

Decreased capacity for mental effort after single supratentorial lacunar infarct may affect performance in everyday life.

OBJECTIVES: The long term outcome after a single symptomatic lacunar infarct may be less favourable than is generally assumed. Patients often present with complaints such as fatigue or "being different from before the stroke", for which there are no obvious physical explanations. Although cognitive functioning is considered normal in most patients with lacunar infarction in the internal capsule or corona radiata, a study was carried out to determine if subclinical changes in mental or emotional function can explain these vague complaints characteristic for their disablement. METHODS: Sixteen patients, each with a single symptomatic supratentorial lacunar infarct, and 16 matched healthy controls were examined with an extensive neuropsychological screening battery and a standardised questionnaire aimed at emotional problems. The mean number of correct responses was calculated for each subject and averaged within each group. RESULTS: Although, on the whole, there were no differences in performance, patients' results on the following tasks in different modalities showed evidence for decreased performance under relatively more demanding conditions: line orientation task (mean difference (MD) 261 ms; 95% confidence interval (95%CI) 94 to 428), Rey-Osterrieth delayed recall (MD-3.8, 95% CI -7.5 to 0.0), visual elevator subtest of the everyday attention task (EAT) (MD -0.7, 95% CI -1.5 to 0.1), lottery subtest of the EAT (MD -0.6, 95% CI -1.3 to 0.1) and WAIS similarities (MD -3.2 95% CI -6.3 to 0.1). Patients also more often had emotional disturbances than controls. CONCLUSION: Both subtle cognitive impairments and emotional disturbances may play a part in the decreased competence in everyday life of patients with a supratentorial lacunar infarct.

Activities of Daily Living↗

PubMed1998

Headache characteristics in subarachnoid haemorrhage and benign thunderclap headache.

One third of patients with aneurysmal subarachnoid haemorrhage (ASAH) present with headache only. A prompt diagnosis is crucial, but these patients must be distinguished from patients with non-haemorrhagic benign thunderclap headache (BTH). The headache characteristics and associated features at onset in subarachnoid haemorrhage and benign thunderclap headache were studied to delineate the range of early features in these conditions. In this prospective study, one of two observers interviewed 102 patients with acute severe headache by means of a standard questionnaire. The patients were alert on admission and had no focal deficits. ASAH was subsequently diagnosed in 42 patients, non-aneurysmal perimesencephalic haemorrhage (PMH) in 23 patients, and BTH in 37 patients. Headache developed almost instantaneously in 50% of patients with ASAH, 35% of patients with PMH, and 68% of patients with BTH and within 1 to 5 minutes in 19%, 35%, and 19%, respectively. Loss of consciousness was reported in 26% of patients with ASAH, 4% of patients with PMH and 16% of patients with BTH, and transient focal symptoms in 33%, 9%, and 22% respectively. Seizures and double vision had occurred only in ASAH. Vomiting and physical exertion preceding the onset of headache were more frequent in patients with ASAH (69% and 50%) and those with PMH (83% and 39%) than in those with BTH (43% and 22%). Headache developed almost instantaneously in only half the patients with aneurysmal rupture and in two thirds of patients with benign thunderclap headache. In patients with acute severe headache, female sex, the presence of seizures, a history of loss of consciousness or focal symptoms, vomiting, or exertion increases the probability of ASAH, but these characteristics are of limited value in distinguishing ASAH from BTH. Aneurysmal rupture should be considered even if focal signs are absent and the headache starts within minutes.

Acute Disease↗