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Biomedical subjects

A Algra

Publications and source records attributed to A Algra.

At least 199 records · Page 11Linked to original sources

Predictive value of clinical history and electrocardiogram in patients with transient ischemic attack or minor ischemic stroke for subsequent cardiac and cerebral ischemic events. The Dutch TIA Trial Study Group.

OBJECTIVE: Patients with cerebral ischemia have a high mortality rate. The most common cause of death is myocardial infarction. We attempted to identify risk factors for subsequent cardiac events in patients with cerebral ischemia by means of the history and electrocardiography performed with the patient at rest. DESIGN: The original inception cohort was entered in a multicenter randomized clinical trial (30 or 283 mg/d of aspirin) and followed up prospectively for a mean period of 2.6 years. SETTING: Patients were admitted to the hospital or seen in outpatient clinics. PATIENTS: Patients with one or more transient ischemic attacks (symptoms completely reversible within 24 hours) and patients with minor ischemic stroke (symptoms persisting for longer than 24 hours) were randomized, provided they were independent in most activities of daily living. Patients with a definite or probable source of embolism in the heart were excluded. A total of 3021 patients were included in the study. Follow-up was performed at 4-month intervals. MAIN OUTCOME MEASURES: Primary cardiac outcome events were defined as nonfatal myocardial infarction and cardiac death. Cardiac death included sudden death, fatal myocardial infarction, or death due to congestive heart failure; 189 patients suffered a cardiac death--82 of which were sudden deaths--or nonfatal myocardial infarction. RESULTS: By means of multivariate analysis, the following independent predictors for cardiac events were identified (hazards ratio/95% confidence limits): age older than 65 years (1.6/1.2 to 2.2), male sex (1.5/1.1 to 2.1), angina pectoris (1.5/1.0 to 2.3), diabetes (1.6/1.1 to 2.5), anterior infarction noted on electrocardiography (1.7/1.1 to 2.7), inverted T wave noted on the electrocardiogram (1.6/1.1 to 2.4), and left ventricular hypertrophy noted on electrocardiography (3.2/2.0 to 4.9). CONCLUSIONS: The history and the electrocardiogram obtained with the patient at rest are valuable tools for cardiac risk assessment in patients with recent cerebral ischemia.

Adult↗

Benefits of carotid patching: a prospective randomized study with long-term follow-up.

A prospective study with random selection between primary closure and saphenous vein patching after carotid endarterectomy was conducted. Patients were evaluated with intravenous digital subtraction angiography during the initial postoperative period, followed by duplex scanning at 3 and 6 months, and then yearly examinations. The series consisted of 129 carotid endarterectomies, of which 62 were primary closures and 67 were patch procedures. Both groups were identical with regard to risk factors, symptoms, and postoperative control digital subtraction angiography. Restenosis was defined as a stenosis with > or = 50% diameter reduction, as assessed by duplex scanning. Of special interest was the development of restenosis along with the occurrence of cerebrovascular symptoms at long-term follow-up. The follow-up data from the 129 carotid endarterectomies are presented in a life-table analysis. The mean length of follow-up was 5 years (range 1 to 96 months). During the follow-up period 38 patients who had undergone 39 operations died (mortality rate 30%); three deaths were attributed to cerebral causes (two in-hospital deaths due to intracerebral hemorrhage and one cerebral hemorrhage after 6 months). Restenosis occurred in 25 cases (19%). This restenosis was detected in 5 of 45 men with primary closure (11%), 12 of 17 women with primary closure (70%), 7 of 49 men with patch closure (14%), and 1 of 18 women with patch closure (5.5%). The difference between patch and primary closures was found to be statistically significant (hazard ratio 0.39; 95% confidence interval 0.17 to 0.91; p = 0.03).(ABSTRACT TRUNCATED AT 250 WORDS)

Carotid Stenosis↗

Silent infarction on a second CT scan in 91 patients without manifest stroke in the Dutch TIA trial.

The frequency of silent infarction is an important issue because it is a marker of vascular disease. We studied the occurrence of silent infarction in a sample of patients from the Dutch TIA trial, in which patients were randomized between 30 and 283 mg of aspirin. A total of 91 patients with TIA or non-disabling ischemic stroke and who did not suffer a stroke during a period of one to four years (mean 32 months) underwent CT scanning both on entry and at the end of the study. A cardiac source of embolism was an exclusion criterion for the trial. We found only one patient with a possibly silent infarction; in four patients a previously detected symptomatic infarct on CT was no longer visible. The rarity of silent infarction in this study may have several explanations; (1) the relatively short period of follow-up, (2) the selection of patients (no cardiac source of embolism), (3) the clinical monitoring at four monthly intervals aimed at detection of focal ischemia, (4) the use of aspirin. Given these circumstances, silent infarction is an infrequent problem.

Adult↗

Electroencephalography improves the prediction of functional outcome in the acute stage of cerebral ischemia.

BACKGROUND AND PURPOSE: We studied the value of clinical and electroencephalographic assessment in patients with acute first-ever supratentorial ischemia in predicting functional outcome after 1 year. METHODS: In 55 consecutive patients admitted after a median interval of less than 24 hours, the degree of handicap was dichotomized as moderate (Rankin grade 1, 2, or 3) or severe (Rankin grade 4 or 5). Clinical deficits were categorized according to signs of a lacunar or a cortical syndrome. Without knowledge of clinical data, electroencephalograms (EEGs) were classified according to findings predicting good or poor prognosis. The outcome after 1 year was assessed as good (Rankin grade 3 or less) or poor (Rankin grade 4 or 5 or death from stroke) and was correlated to clinical data and to EEG findings in the acute stage. RESULTS: Thirty patients with a moderate handicap on admission all had a good outcome (predictive value [PV] of the initial handicap, 1.00; 95% confidence interval [CI], 0.88 to 1.00). Of the 25 patients with severe handicap on admission a poor outcome occurred in 13 (PV, 0.52; 95% CI, 0.31 to 0.72). If these patients with severe handicap at baseline were subdivided according to clinical features, a lacunar syndrome predicted good outcome in 4 of 5 patients (PV, 0.80; 95% CI, 0.28 to 1.00), but a cortical syndrome predicted poor outcome in only 12 of 20 patients (PV, 0.60; 95% CI, 0.36 to 0.81). Of the 20 patients with severe handicap and a cortical syndrome at baseline, an EEG with features predicting a good prognosis correctly predicted good outcome in 6 of 7 patients (PV, 0.86; 95% CI, 0.42 to 1.00). An EEG with features predicting poor prognosis correctly predicted poor outcome in 11 of 13 patients (PV, 0.85; 95% CI, 0.55 to 0.98). CONCLUSIONS: Electroencephalography improves the prediction of functional outcome in patients with a severe neurological deficit in the acute stage of cerebral ischemia. This may have implications for the design of future intervention trials in acute stroke.

Activities of Daily Living↗

Protection against lethal endotoxemia by anti-lipid A murine monoclonal antibodies: comparison of efficacy with that of human anti-lipid A monoclonal antibody HA-1A.

The protective capacities of murine anti-lipid A monoclonal antibodies (MAbs) 8-2 and 26-20 were examined and compared with those of the human MAb HA-1A with respect to inhibition of lipopolysaccharide (LPS) priming of human polymorphonuclear leukocytes (PMNL) in vitro and protection against lethal endotoxemia in mice. HA-1A did not prevent the priming effect of either rough or smooth LPS, while MAb 26-20 effectively inhibited LPS priming of human PMNL. Also, both murine MAbs protected mice against an otherwise lethal challenge with rough Re LPS of S. minnesota R595 as well as with smooth LPS of E. coli O111:B4. HA-1A exerted no protection against the lethal effects of Re LPS in this in vivo model. The enhanced survival in mice by treatment with MAbs 8-2 and 26-20 was associated with decreased levels of LPS-induced tumor necrosis factor. Neutralization of lipid A as a mechanism of protection was strongly suggested by efficacious inhibition of LPS priming of human PMNL by MAbs 8-2 and 26-20 in vitro.

Animals↗

Escherichia coli in bacteremia: O-acetylated K1 strains appear to be more virulent than non-O-acetylated K1 strains.

A total of 174 blood isolates of Escherichia coli, collected during a 5-year period at the University Hospital Utrecht, were serotyped with rabbit sera against 171 O antigens and 73 capsule (K) antigens. The four most prevalent O-antigen serotypes were O6 (n = 22), O18 (n = 19), O1 (n = 19), and O2 (n = 15). Thirty-one strains were not typeable with any of the O-antigen-typing sera. Of the 148 strains that were subjected to K-antigen serotyping, 34 strains lacked a K antigen and 41 were not typeable with the K-antigen-specific antisera used in the study. K1 was by far the most frequently found K-antigen serotype; this was followed by K2, K53, K5, K13, K7, K(A)28, and K15. Strains possessing a K1 antigen were further classified as either O-acetyl-positive (n = 12) or O-acetyl-negative (n = 21) strains. Retrospective analysis of patients infected with different E. coli isolates--nonencapsulated (n = 23), O-acetylated K1 (n = 12), and non-O-acetylated K1 (n = 21)--revealed clinical differences. More patients suffered from sepsis (94% versus 74%), and a higher rate of mortality was found in the group infected with K1 isolates (18 versus 9%) than in the group infected with nonencapsulated isolates. More patients with severe sepsis (25 versus 10%) and a higher mortality (33 versus 10%) were found in the group infected with O-acetylated K1 isolates than in the group infected with non-O-acetylated isolated. Also, the hospitalization of these patients was prolonged. Thus, O-acetylated E. coli K1 strains seem to be more virulent than non-O-acetylated K1 strains.

Acetylation↗

QT interval variables from 24 hour electrocardiography and the two year risk of sudden death.

OBJECTIVE: To study the effects of variability in the duration of the QT interval corrected for heart rate (QTc) on the occurrence of sudden death. DESIGN: Nested case-referent study. SUBJECTS: Cohort of 6693 consecutive patients who underwent 24 hour electrocardiography and were followed up for two years. Risk implications of QTc interval variables were studied in patients without evidence of cardiac dysfunction or of an intraventricular conduction defect (104 died suddenly and 201 patients were randomly drawn from the study cohort). MAIN OUTCOME MEASURES: Mean QTc interval duration and variation in QTc duration over time correlated with occurrence of sudden death. RESULTS: Patients with a prolonged mean QTc over 24 hours (> or = 440 ms) had a 2.3 times (95% confidence interval 1.3 to 4.5) higher risk of dying suddenly than patients with a normal mean QTc (400-440 ms); patients with a shortened mean QTc (< 400 ms) also had a higher risk (relative risk 2.4 (1.4 to 4.3)). Patients with low (< 20 ms) and high (> or = 25 ms) long term variation in QTc duration had an increased risk of dying suddenly compared with those with intermediate variation (20-25 ms) (relative risks 2.2 (1.2 to 4.2) and 2.3 (1.4 to 4.2) respectively). The relative risks for low and high short term variation were not significantly raised. CONCLUSIONS: A prolonged and a shortened mean QTc interval over 24 hours was associated with a more than twofold risk of sudden death compared with intermediate mean QTc values (400-440 ms). Neither short nor long term variability in QTc had a distinct relation with the risk of sudden death.

Case-Control Studies↗

Contribution of the 24 hour electrocardiogram to the prediction of sudden coronary death.

BACKGROUND: Sudden coronary death is a major public health issue. The identification of patients at high risk should therefore be as efficient as possible. This study compares simple and more elaborate risk stratification procedures. METHODS: Risk functions for the prediction of sudden death were determined in a population of 6693 consecutive patients who had 24 hour electrocardiography for various indications. The functions were based on the clinical and electrocardiographical data on 245 patients who died suddenly during 2 year follow up and 467 patients randomly drawn from the total study population. RESULTS: The model based on history (age, sex, myocardial infarction, congestive heart failure, palpitation, syncope, use of diuretics, and use of nitrates), 12 lead electrocardiography (major intraventricular conduction defect, T wave abnormality, and ST depression > or = 0.05 mV), and standard rhythm analysis of 24 hour electrocardiography (ventricular tachycardia, frequent premature atrial complexes, sinus tachycardia (> 150 min-1), and atrial fibrillation) was almost as efficient in the prediction of sudden death as extended models that also contained information from exercise testing, echocardiography, ventriculography, and computer-aided re-analysis of 24 hour electrocardiography (QT and RR interval variability). CONCLUSIONS: These results indicate that additional information from advanced function tests does little to increase the efficiency of prediction of sudden coronary death over that of tests based on history, the standard 12 lead electrocardiogram, and 24 hour electrocardiography.

Cohort Studies↗

Heart rate variability from 24-hour electrocardiography and the 2-year risk for sudden death.

BACKGROUND: Low heart rate variability has been implicated as a risk factor for sudden death. However, no large epidemiological studies using sudden death as an outcome event have been reported. METHODS AND RESULTS: A total of 6,693 consecutive patients who underwent 24-hour ambulatory ECG were followed up for 2 years; of these, 245 patients died suddenly. Clinical data at the time of 24-hour ambulatory ECG were collected for all patients who died suddenly and for a random sample of 268 patients from the study cohort. In all patients in sinus rhythm with or without occasional supraventricular arrhythmias at the 24-hour ECG (193 patients who died suddenly and 230 patients from the sample), heart rate variability parameters were derived. Patients with low short-term RR interval variability (mean during 24 hours of per-minute standard deviations [SD] of RR intervals < 25 msec) had a 4.1-fold higher risk (95% confidence interval [CI], 2.6, 8.1) for sudden death than patients with high short-term variability (> or = 40 msec); after adjustment for age, evidence of cardiac dysfunction, and history of myocardial infarction, the relative risk was 2.6 (95% CI, 1.4, 5.1). The crude relative risk of long-term RR interval variability (SD during 24 hours of per-minute means of RR intervals < 8 msec) was 4.4 (95% CI, 2.6, 7.7); after adjustment for the same risk factors, it was 2.2 (95% CI, 1.2, 4.1). Patients with a minimum heart rate > or = 65 beats per minute had a double risk of sudden death compared with those with a minimum heart rate < 65 beats per minute (adjusted relative risk, 2.1; 95% CI, 1.3, 3.6). CONCLUSIONS: These findings support the theory that patients with low parasympathetic activity (low short-term RR interval variability) have an increased risk for sudden death independent of other risk factors.

Autonomic Nervous System↗

Does cerebral infarction after a previous warning occur in the same vascular territory?

BACKGROUND AND PURPOSE: The aim of this study was to compare the territory of cerebral infarcts on follow-up with that of the preceding transient ischemic attack or nondisabling stroke. METHODS: The Dutch TIA Trial was a randomized, double-blind, controlled trial, in which the secondary preventive effects of two doses of aspirin were compared in patients with a transient ischemic attack or nondisabling stroke. On the basis of clinical symptoms and computed tomography, qualifying events were classified as pertaining to the left carotid, right carotid, or vertebrobasilar circulation. RESULTS: In 2,993 patients the territory of the qualifying event was that of the left carotid in 1,281 (43%), the right carotid in 1,090 (36%), and the vertebrobasilar in 444 (15%); the territory was uncertain in 178 (6%). On follow-up (mean, 2.6 years), 184 of the 2,371 patients with a baseline event in the carotid circulation suffered a recurrent ischemic stroke (7.8%), as did 28 of the 444 patients in the vertebrobasilar group (6.3%); 117 of these 212 infarcts (55%; 95% confidence interval, 49-62) occurred in the same territory (108 in the ipsilateral carotid and nine in the vertebrobasilar territory) as the event at baseline, compared with 39% to be expected by chance alone (95% confidence interval, 32-45). In the carotid groups patients were significantly more likely to have a subsequent ischemic event in the same territory as at entry than patients in the vertebrobasilar group (relative risk, 1.8; 95% confidence interval, 1.1-3.2). The average interval between the qualifying event and the subsequent stroke was significantly shorter (mean, 167 days; 95% confidence interval, 77-257) if the vascular territory was the same. CONCLUSIONS: These results suggest that single artery disease accounts for at most one half of the strokes on follow-up, relatively more often in the carotid territory, and that recurrent strokes from the same arterial lesion occur sooner than strokes associated with other lesions.

Aspirin↗

[How much information is retained by participants in clinical trials?].

OBJECTIVE: To assess which information participants of the Dutch TIA trial could remember from the informed consent procedure. DESIGN: Descriptive investigation. SETTING: The University Hospital Utrecht and the University Medical Centre Amsterdam. METHODS: One hundred of the 308 patients from 2 of the 63 participating clinical centres (the University Hospital Utrecht and the University Medical Centre Amsterdam), were selected at random for telephone interviews. Nineteen were not interviewed, most of them because they did not have access to a telephone. By a weighted score based on the replies the influence of some baseline variables was explored. The information sheet that patients had received was analysed with the readability tests of Flesh and Fry. RESULTS: Eighty-six percent of all patients were aware of the correct diagnosis. The name and action of the trial drug Ascal (a brand of acetylsalicylic acid) were retained better than those of atenolol. The nature of the disease and therapy were better known than the design of the trial. Of the baseline variables explored only the level of education was significantly related to what patients remembered about the trial. The readability of the information sheet required more education than was intended. CONCLUSION: Although we did not study a random sample the conclusion seems warranted that the level of information was not optimal in this trial.

Adult↗