Modeling Stroke Diagnosis with the Use of Intelligent Techniques

The purpose of this work is to test the efficiency of specific intelligent classification algorithms when dealing with the domain of stroke medical diagnosis. The dataset consists of patient records of the ”Acute Stroke Unit”, Alexandra Hospital, Athens, Greece, describing patients suffering one of 5 different stroke types diagnosed by 127 diagnostic attributes / symptoms collected during the first hours of the emergency stroke situation as well as during the hospitalization and recovery phase of the patients. Prior to the application of the intelligent classifier the dimensionality of the dataset is further reduced using a variety of classic and state of the art dimensionality reductions techniques so as to capture the intrinsic dimensionality of the data. The results obtained indicate that the proposed methodology achieves prediction accuracy levels that are comparable to those obtained by intelligent classifiers trained on the original feature space

Hypothyroidism as a protective factor in acute stroke patients

Objective It has been reported that hypothyroidism is associated with better survival in elderly persons. We investigated possible associations of thyroid status with clinical outcome in patients with acute stroke. Design Retrospective analysis. Patients Consecutive patients (median age 70 years) admitted for acute stroke. Measurements Total T3, T4 and TSH levels. Stroke severity evaluation using the Scandinavian Stroke Scale (SSS) and the Glasgow Coma Score (GCS). Handicap and survival assessment over 12 months. Results Of 744 patients where thyroid function tests were available within the first 24 h of stroke, 13 had elevated TSH (>= 10 mu U/ml; range 10-42 mu U/ml) (hypo-group), 51 had mildly elevated TSH (3.3-9.9 mu U/ml) and 680 had nonelevated TSH < 3.3 mu U/ml. In the hypo-group transient ischaemic attacks (TIA’s) were more prevalent (46.2%) compared to the groups of mildly elevated TSH (11.8%) and nonelevated TSH (12.4%, P < 0.002). Hypo-group had more frequently an adequate level of consciousness (GCS 14-15 = fully alert): 92.3% vs 74.5% and 63.7% (P = 0.033), a milder neurological deficit (SSS score 45-58) 76.9% vs 39.2% and 38.7% (P = 0.02) compared to the other two groups, respectively, and a tendency for lower glucose levels on admission. One year outcome tended to be better with respect to survival and handicap. Conclusions Acute stroke patients with laboratory findings compatible with pre-existing hypothyroidism on admission, appear to have better clinical presentation and outcome; we speculate that a reduced response to stress and previous TIA’s, possibly related to endogenous ‘preconditioning’, may contribute to this phenomenon

Stroke aetiology and predictors of outcome in patients with heart failure and acute stroke: a 10-year follow-up study

Aims The aim of this study was to investigate stroke aetiology and assess the predictors of early and late outcome in patients with heart failure (HF) and acute stroke. Methods and results A total of 2904 patients, admitted between 1993 and 2010, were regularly followed up at months 1, 3, and 6, and yearly thereafter up to 10 years. There were 283 (9.7%) stroke patients with HF; atrial fibrillation (AF) was present in 144 (50.9%) of them. Stroke aetiology in patients with HF and AF was mainly cardioembolism (82%) regardless of HF aetiology. In contrast, in the 139 non-AF patients with HF, the stroke mechanism was associated with the aetiology of HF: valvular heart disease and dilated cardiomyopathy were related to cardioembolism in 60% and 66.7% of patients, respectively, whereas HF due to coronary artery disease or hypertension was associated with atherosclerotic and lacunar stroke in 40.8% and 61.5%, respectively. In the overall population, HF was an independent predictor of 10-year mortality [hazard ratio = 1.54, 95% confidence interval (CI) 1.29-1.83; P < 0.001]. Probability of 10-year survival was 19.4% (95% CI 14.5-23.5) for HF patients and 44.1% (95% CI 41.4-46.8) for non-HF patients (P < 0.0001). Ten-year mortality in HF patients was associated with functional class of HF, age, diabetes, stroke severity, and in-hospital aspirin use. The presence of AF in HF stroke patients did not influence 10-year survival and composite cardiovascular events (P = 0.429 and P = 0.406, respectively). Conclusions In patients with HF, stroke aetiology is influenced by the presence of AF and the underlying cause of HF. Early and late stroke outcome is associated with HF severity but not with the presence of AF

New England Medical Center Posterior Circulation registry.

Among 407 New England Medical Center Posterior Circulation registry patients, 59% had strokes without transient ischemic attacks (TIAs), 24% had TIAs then strokes, and 16% had only TIAs. Embolism was the commonest stroke mechanism (40% of patients including 24% cardiac origin, 14% intraarterial, 2% cardiac and arterial sources). In 32% large artery occlusive lesions caused hemodynamic brain ischemia. Infarcts most often included the distal posterior circulation territory (rostral brainstem, superior cerebellum and occipital and temporal lobes); the proximal (medulla and posterior inferior cerebellum) and middle (pons and anterior inferior cerebellum) territories were equally involved. Severe occlusive lesions (\u3e50% stenosis) involved more than one large artery in 148 patients; 134 had one artery site involved unilaterally or bilaterally. The commonest occlusive sites were: extracranial vertebral artery (52 patients, 15 bilateral) intracranial vertebral artery (40 patients, 12 bilateral), basilar artery (46 patients). Intraarterial embolism was the commonest mechanism of brain infarction in patients with vertebral artery occlusive disease. Thirty-day mortality was 3.6%. Embolic mechanism, distal territory location, and basilar artery occlusive disease carried the poorest prognosis. The best outcome was in patients who had multiple arterial occlusive sites; they had position-sensitive TIAs during months to years