Risk of strut fracture of Björk-Shiley convexo-concave valves.
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Biomedical subjects
Publications and source records attributed to A Algra.
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Proposed guidelines for the diagnosis of transient ischaemic attack (TIA) involve interpretation of symptoms, so it can be very difficult to distinguish a TIA from other disorders, such as migraine, epilepsy, syncope, or neurosis. Atypical cerebral and visual events may be classified as TIA. To see whether TIA or stroke patients with atypical cerebral or visual symptoms are at high or low risk of cardiac complications, we prospectively followed 572 patients (entered into the Dutch multicentre TIA trial) with a diagnosis of TIA or minor ischaemic stroke, but whose symptoms did not fully accord with internationally accepted criteria. We compared their outcome with that of 2555 other TIA or stroke patients in the trial, who had unequivocal symptoms; all patients were treated with aspirin. During mean follow-up of 2.6 years the risk of a major vascular event did not differ between the groups (14.5% in patients with atypical symptoms vs 15.1% of patients with typical attacks). Patients with atypical attacks had a lower risk of stroke (5.6% vs 9.4%, hazard ratio 0.6, 95% confidence interval 0.4-0.9) and a higher risk of a major cardiac event (8.4% vs 5.9%, 1.4, 1.0-2.0) than did patients with typical attacks. These differences could not be explained by differences in cardiac risk factors, and were independent of minor discrepancies in baseline characteristics between the groups. A heavy or tired feeling in one or two limbs was the only atypical symptom associated with cerebral rather than cardiac events (ratio cardiac/cerebral events 0.8). For all other atypical symptoms cardiac events were about twice as common as cerebral events (range 1.3-2.5). Our findings suggest that TIA or minor stroke patients with atypical symptoms may have symptomatic heart disease, especially cardiac arrhythmia.
In a prospective study of 3,017 patients with transient ischemic attack or minor ischemic stroke from the Dutch Transient Ischemic Attack Trial, the presence or absence of diffuse hypodensity of the white matter on a baseline computed tomography (CT) scan of the brain was related to the occurrence of subsequent stroke. On entry, 337 patients were judged to have diffuse hypodensity of the white matter on CT; they were older (71.4 +/- 7.4 years versus 64.4 +/- 9.9 years), more often had hypertension (50% versus 41%), and more often had lacunar infarcts on CT scan (40% versus 26%) than did patients with normal white matter. Strokes, fatal or nonfatal, occurred in 51 (15%) of the patients with diffuse hypodensity of the cerebral white matter, compared to 217 (8%) in the group with normal white matter (crude hazard ratio, 2.0; 95% confidence interval, 1.4-2.7). After adjustment for age and other relevant entry variables, the hazard ratio was 1.6 (95% confidence interval, 1.2-2.2). In patients younger than 70 years the crude hazard ratio was 2.7 (95% confidence interval, 1.7-4.2). The distribution between the main subtypes of stroke was similar for patients with and those without diffuse hypodensity of the cerebral white matter: Intracerebral hemorrhage occurred in 6 and 9%, cortical infarction in 47 and 45%, and lacunar infarction in 34 and 29%, respectively. We conclude that hypodensity of the cerebral white matter in patients with transient ischemic attack or minor stroke is associated with an extra risk of future stroke, from large as well as from small vessels, and particularly in patients under 70 years old; this increase of risk is independent of other risk factors for stroke.
In a prospective study, the prognostic value of clinical characteristics in 157 consecutive patients with spontaneous supratentorial intracerebral haemorrhage were examined by means of multivariate analysis. Two days after the event 37 (24%) patients had died. Factors independently contributing to the prediction of two day mortality were pineal gland displacement on CT of 3 mm or more (p less than 0.001), blood glucose level on admission of 8.0 mmol/l or more (p = 0.01), eye and motor score on the Glasgow Coma Scale of eight out of 10 or less (p = 0.022) and haematoma volume of 40 cm3 or more (p = 0.037). Between the third day and one year after the event another 46 of the 120 two day survivors had died; the independent prognostic indicators for death during that period were: age 70 years or more (p less than 0.001) and severe handicap (Rankin grade five) on the third day (p less than 0.001). Functional independence (Rankin grade two or less) at one year was most common not only with the converse features of age less than 70 years (p less than 0.01) and Rankin grade four or less on the third day (p = 0.002), but also with an eye and motor score on the Glasgow Coma Scale of nine or 10 on the third day (p less than 0.001). The 120 patients with intracerebral haemorrhage who were still alive two days after the event were matched with 120 patients with cerebral infarction, according to age, level of consciousness on the third day after stroke (Glasgow Coma Scale) and handicap (Rankin grade). Survival and handicap after one year did not differ between these two groups. The conclusion drawn is that it is not the cause (intracerebral haemorrhage or cerebral infarction) but the extent of the brain lesion that determines the outcome in patients who survive the first two days.
BACKGROUND AND PURPOSE: We studied silent stroke (i.e., infarcts on computed tomographic scan not related to later symptoms) in patients after transient ischemic attack or minor ischemic stroke. METHODS: Ours is a cross-sectional study of 2,329 patients who were randomized in a secondary prevention trial after transient ischemic attack or minor ischemic stroke and had no residual deficit after the qualifying event. RESULTS: Silent stroke was observed in 13% of the 2,329 patients. Lacunes formed 79%, cortical lesions 14%, and border zone lesions 7% of all silent strokes. Silent lacunes were most often located in the basal ganglia and symptomatic lacunes most often in the corona radiata. Age, hypertension, and current cigarette smoking were related to the presence of silent stroke. Silent stroke was equally common in different types of transient ischemic attack, including transient monocular blindness. Residual symptoms of any kind were more common in patients with silent stroke than in those without. CONCLUSIONS: Because only the sites of silent stroke infarcts differed slightly from those of symptomatic infarcts and the frequency of vascular risk factors was similar to that of symptomatic infarcts, silent stroke may have the same bearing on future risk as known prior stroke.
BACKGROUND: QTc prolongation has been implicated as a risk factor for sudden death; however, a controversy exists over its significance. METHODS AND RESULTS: In the Rotterdam QT Project, 6,693 consecutive patients who underwent 24-hour ambulatory electrocardiography were followed up for 2 years; of these, 245 patients died suddenly. A standard 12-lead electrocardiogram and clinical data at the time of 24-hour ambulatory electrocardiography were collected for all patients who died suddenly and for a random sample of 467 patients from the study cohort. In all patients without an intraventricular conduction defect (176 patients who died suddenly and 390 patients from the sample), QT interval duration was measured in leads I, II, and III and corrected for heart rate with Bazett's formula (QTc). In patients without evidence of cardiac dysfunction (history of symptoms of pump failure or an ejection fraction less than 40%), QTc of more than 440 msec was associated with a 2.3 times higher risk for sudden death compared with a QTc of 440 msec or less (95% confidence interval: 1.4, 3.9). In contrast, in patients with evidence of cardiac dysfunction, the relative risk of QTc prolongation was 1.0 (0.5, 1.9). Adjustment for age, gender, history of myocardial infarction, heart rate, and the use of drugs did not alter these relative risks. CONCLUSIONS: These data indicate that in patients without intraventricular conduction defects and cardiac dysfunction, QTc prolongation measured from the standard electrocardiogram is a risk factor for sudden death independent of age, history of myocardial infarction, heart rate, and drug use. In patients with cardiac dysfunction, QTc duration is not related to the risk for sudden death.
QT-interval prolongation is a recognized risk indicator for ventricular arrhythmias and sudden cardiac death. The effect of beta-blockers on the change of the QT-interval relative to the change in heart rate was studied in 269 male patients who underwent computer-interpreted exercise tests. None of the patients studied used anti-arrhythmic drugs, diuretics or digoxin. In 141 men on beta-blockers the relation between Q-peakT interval and heart rate could be described as follows: Q-peakT = -1.48 X heart rate + 415. In 128 patients not on beta-blockers this relation was: Q-peakT = -1.14 X heart rate + 379. The difference of the slopes is 0.34 (0.22 - 0.46, 95% confidence interval). This difference was even more pronounced in a subgroup of coronary patients: 0.44 (0.30 - 0.57, 95% confidence interval). These results indicate that in men using beta-blockers the QT-interval shortens faster with increasing heart rate than in men not using them. At high heart rates patients on beta-blockers have a shorter QT-interval than those not using them. These observations could explain the beneficial effect of beta-blockers on exercise-induced ventricular arrhythmias and sudden death in coronary patients.
BACKGROUND: Determinants of survival and of risk of vascular events after transient ischaemic attack (TIA) or minor ischaemic stroke are not well defined in the long term. We aimed to restudy these risks in a prospective cohort of patients after TIA or minor ischaemic stroke (Rankin grade< or =3), after 10 years or more. METHODS: We assessed the survival status and occurrence of vascular events in 2473 participants of the Dutch TIA Trial (recruitment in 1986-89; arterial cause of cerebral ischaemia). We included 24 hospitals in the Netherlands that recruited at least 50 patients. Primary outcomes were all-cause mortality and the composite event of death from all vascular causes, non-fatal stroke, and non-fatal myocardial infarction. We assessed cumulative risks by Kaplan-Meier analysis and prognostic factors with Cox univariate and multivariate analysis. FINDINGS: Follow-up was complete in 2447 (99%) patients. After a mean follow-up of 10.1 years, 1489 (60%) patients had died and 1336 (54%) had had at least one vascular event. 10-year risk of death was 42.7% (95% CI 40.8-44.7). Age and sex-adjusted hazard ratios were 3.33 (2.97-3.73) for age over 65 years, 2.10 (1.79-2.48) for diabetes, 1.77 (1.45-2.15) for claudication, 1.94 (1.42-2.65) for previous peripheral vascular surgery, and 1.50 (1.31-1.71) for pathological Q waves on baseline electrocardiogram. 10-year risk of a vascular event was 44.1% (42.0-46.1). After falling in the first 3 years, yearly risk of a vascular event increased over time. Predictive factors for risk of vascular events were similar to those for risk of death. INTERPRETATION: Long-term secondary prevention in patients with cerebral ischaemia still has room for further improvement.
An attack of abrupt loss of vision in one eye that recovers completely after a short period is called "transient monocular blindness" (TMB) or amaurosis fugax. The most common cause of TMB is atherothromboembolism from the origin of the internal carotid artery (ICA), whereas atrial fibrillation is quite uncommon. TMB also can be caused by anterior optic nerve ischemia, that is usually caused by thrombosis in the posterior ciliary artery. Thrombosis in the central retinal vein may be another cause. Dissection of the ICA, vascular malformations, or fibromuscular dysplasia are other potential etiologies. Blurring of vision as compared with blackened vision or positive phenomena such as flashing is probably associated with a higher risk of future cardiovascular events, whereas involvement of the partial monocular field is associated with a relative benign prognosis. In patients with atherosclerosis, antiplatelet therapy is indicated and treatment of vascular risk factors should have high priority. Carotid endarterectomy should be performed only in case of an ICA stenosis of more than 70% in the presence of at least one other risk factor for stroke.