Harri Rusanen

The mid-M1 segment of the middle cerebral artery is a cutoff clot location for good outcome in intravenous thrombolysis.

Background and purpose:  We studied the impact of the location of the thrombus (internal carotid artery, proximal M1 segment, distal M1 segment, M2 segment, and M3 segment of the middle cerebral artery) in predicting the clinical outcome of patients treated with intravenous thrombolytic therapy (<3 h) in a retrospective cohort.

Safety of low-dose subcutaneous enoxaparin for the prevention of venous thromboembolism after primary intracerebral haemorrhage

BACKGROUND The risks and benefits of low molecular weight heparins (LMWH) for the prevention of deep-vein thrombosis (DVT) and pulmonary embolism (PE) after intracerebral haemorrhage (ICH) have not been assessed. The few studies on this subject have revealed conflicting results. METHODS We retrospectively evaluated whether subcutaneous enoxaparin (20 mg daily) reduced symptomatic venous complications or caused increased 3-month death rate. We included 407 patients who were admitted to a stroke unit and survived the first two days after onset of ICH. There were 232 patients who received anticoagulant treatment for the prevention of DVT and PE and 175 who did not. RESULTS Despite the fact that the treated patients were in worse clinical condition at the start of the treatment, 3-month death rate was 19% among them compared to 21% among those not receiving anticoagulant therapy. Low-dose subcutaneous enoxaparin (20 mg once daily) induced a significant plasma anti-factor Xa activity 2-3 hours after administration (p=0.018). Haematoma enlargements (33%) occurred in 9% and 7% of the treated and untreated patients, whereas symptomatic venous thromboembolic complications were observed in 3% and 2%, respectively. CONCLUSIONS We did not observe any increased mortality among ICH patients who survived the first 2 days after the onset of ICH and were thereafter treated with enoxaparin 20 mg daily relative to patients remaining untreated. A randomized trial of the effect of LMWH with a higher dose in prevention of venous thromboembolic complications would be indicated.

CT Perfusion ASPECTS in the Evaluation of Acute Ischemic Stroke: Thrombolytic Therapy Perspective

Background and Purpose: Advances in the management of acute ischemic stroke and medical imaging are creating pressure to replace the rigid one-third middle cerebral artery (MCA) and non-contrast-enhanced CT (NCCT) Alberta Stroke Program Early CT Score (ASPECTS) thresholds used for the selection of patients eligible for intravenous thrombolytic therapy. The identification of potentially salvageable ischemic brain tissue lies at the core of this issue. In this study, the role of CT perfusion ASPECTS in the detection of reversible ischemia was analyzed. Materials and Methods: We retrospectively reviewed the clinical and imaging data of 92 consecutive patients who received intravenous thrombolytic therapy for acute (duration <3 h) ischemic stroke. Most of the patients underwent admission multimodal CT, and all patients had follow-up NCCT at 24 h. ASPECTS was assigned to all modalities and correlated with clinical and imaging parameters. Receiver-operating characteristic curve analysis was performed to determine optimal thresholds for different parameters to predict clinical outcome. Results: A perfusion defect could be detected in 50% of the patients. ASPECTS correlated inversely with the clinical outcome in the following order: follow-up NCCT > cerebral blood volume (CBV) > mean transit time (MTT) > admission NCCT. The follow-up NCCT and the CBV displayed a statistically significant difference from the admission NCCT, while the MTT did not reach statistical significance. The threshold that best differentiated between good and bad clinical outcome on admission was CBV ASPECTS ≧7. In patients with CT perfusion ASPECTS mismatch, MTT and CBV ASPECTS essentially provided the lower and upper limits for the follow-up NCCT ASPECTS, thus defining the spectrum of possible outcomes. Furthermore, CT perfusion ASPECTS mismatch strongly correlated (r = 0.83) with the mismatch between the tissue at risk and the final infarct, i.e. the amount of salvaged tissue. This finding suggests that the CT perfusion ASPECTS mismatch adequately identifies the amount of potentially salvageable ischemic brain tissue. Conclusions: Parameters derived from the use of CT perfusion ASPECTS can detect reversible ischemia and are correlated with clinical outcome.

Location of the Clot and Outcome of Perfusion Defects in Acute Anterior Circulation Stroke Treated with Intravenous Thrombolysis

These investigators studied the impact of clot location in patients with acute stroke receiving IV thrombolysis. Four locations (ICA, proximal M1, distal M1, and M2 segment and more distal) of clots were correlated with CT perfusion maps, mismatches, salvaged brain volumes, and outcomes in 105 patients. Clots that were more proximal in location produced larger perfusion defects and lesion volumes. The amount of tissue salvaged was greater in patients with more distally located clots. In conclusion, admission CBV defects were larger in proximal vessel occlusions. More of the penumbra was salvaged if the occlusion was located more distally. This effect reached a plateau in the distal M1 segment of the MCA. BACKGROUND AND PURPOSE: The location of the clot is a major determinant of ischemic stroke outcome. We studied the impact of the location (ICA, proximal M1 segment of the MCA, distal M1 segment, and M2 segment and more distally) of the clot on the CT perfusion parametric maps, the mismatch ratio, the amount of salvaged brain tissue, and the imaging and clinical outcomes in a retrospective acute (<3 hours) stroke cohort treated with intravenous thrombolysis. MATERIALS AND METHODS: We reviewed 105 patients who underwent admission multimodal CT that revealed an occluded vessel on CTA. CT perfusion was successfully performed in 58 patients (55%). Differences among the parameters in different vessel positions were studied with the ANCOVA by using onset-to-imaging time as a covariate followed by pair-wise testing. RESULTS: There were no significant differences in potential confounding variables among the groups. A clot proximal to the M2 segment produced a significantly larger defect on the MTT map. A clot in the ICA resulted in a significantly larger CBV lesion compared with the distal M1 segment, the M2 segment, and the M3 segment. In general, a more proximal thrombus created a larger CBV defect. The fraction of penumbra that was salvaged at 24 hours was higher in the more distal vessel positions. CONCLUSIONS: Admission CBV defects are larger in proximal vessel occlusions. More of the penumbra can be salvaged if the occlusion is located distally. This effect seems to reach a plateau in the distal M1 segment of the MCA.

Collateral Score Complements Clot Location in Predicting the Outcome of Intravenous Thrombolysis

BACKGROUND AND PURPOSE: Collateral circulation is an important determinant of stroke outcome. We studied the impact of leptomeningeal collateral circulation with respect to the location of the thrombus in predicting the clinical outcome of patients treated with intravenous thrombolytic therapy (<3 hours) in a retrospective cohort. MATERIALS AND METHODS: Anterior circulation thrombus was detected with CT angiography in 105 patients. Baseline clinical and imaging information was collected, and the site of the occlusion was recorded. Collaterals were assessed by using a 5-grade collateral score and were entered into logistic regression analysis to predict favorable clinical outcome (3-month modified Rankin Scale score of 0–2). RESULTS: Two-thirds of patients with a proximal occlusion displayed poor collateral filling (collateral score 0–1), whereas in more distal clot locations, approximately one-third had poor collaterals. Only 36% of patients with a proximal occlusion and good collaterals experienced favorable clinical outcome. In multivariate analysis, both clot location and collateral score were highly significant (P = .003 and P = .001) and independent predictors of favorable clinical outcome. Good collateral status increased the odds of favorable clinical outcome about 9-fold (OR = 9.3; 95% CI, 2.4–35.8). After dichotomization, a distal clot location had a larger odds ratio (OR = 13.3; 95% CI, 3.0–60.0) compared with the odds ratio of good collaterals (OR = 5.9; 95% CI, 1.8–19.0). CONCLUSIONS: A proximal occlusion in the anterior circulation is associated with poorer collateral status compared with a more distal occlusion. Both the clot location and collateral score are important and independent predictors of favorable clinical outcome of hyperacute stroke treated with intravenous thrombolysis. The location of the clot is a stronger determinant of the outcome than the collateral score.

Collateral Circulation Predicts the Size of the Infarct Core and the Proportion of Salvageable Penumbra in Hyperacute Ischemic Stroke Patients Treated with Intravenous Thrombolysis.

Background: We studied the impact of collateral circulation on CT perfusion (CTP) parametric maps and the amount of salvaged brain tissue, the imaging and clinical outcome at 24 h and at 3 months in a retrospective acute (<3 h) stroke cohort (105 patients) with anterior circulation thrombus treated with intravenous thrombolysis. Methods: Baseline clinical and imaging information were collected and groups with different collateral scores (CS) were compared. Binary logistic regression analyses using good CS (CS ≥2) as the dependent variable were calculated. Results: CTP Alberta Stroke Program Early CT Score (ASPECTS) was successfully assessed in 58 cases. Thirty patients displayed good CS. Poor CS were associated with more severe strokes according to National Institutes of Health Stroke Scale (NIHSS) at arrival (15 vs. 7, p = 0.005) and at 24 h (10 vs. 3, p = 0.003) after intravenous thrombolysis. Good CS were associated with a longer mean onset-to-treatment time (141 vs. 121 min, p = 0.009) and time to CTP (102 vs. 87 min, p = 0.047), better cerebral blood volume (CBV) ASPECTS (9 vs. 6, p < 0.001), better mean transit time (MTT) ASPECTS (6 vs. 3, p < 0.001), better noncontrast CT (NCCT) ASPECTS (10 vs. 8, p < 0.001) at arrival and with favorable clinical outcome at 3 months (modified Rankin Scale ≤2, p = 0.002). The fraction of penumbra that was salvageable at arrival and salvaged at 24 h was higher with better CS (p < 0.001 and p = 0.035, respectively). In multivariate analysis, time from the onset of symptoms to imaging (p = 0.037, OR 1.04 per minute, 95% CI 1.00-1.08) and CBV ASPECTS (p = 0.001, OR 2.11 per ASPECTS point, 95% CI 1.33-3.34) predicted good CS. In similar multivariable models, MTT ASPECTS (p = 0.04, OR 1.46 per ASPECTS point, 95% CI 1.02-2.10) and NCCT ASPECTS predicted good CS (p = 0.003, OR 4.38 per CT ASPECTS point, 95% CI 1.66-11.55) along with longer time from the onset of symptoms to imaging (p = 0.045, OR 1.03 per minute, 95% CI 1.00-1.06 and p = 0.02, OR 1.05 per minute, 95% CI 1.00-1.09, respectively). CBV ASPECTS had a larger area under the receiver operating characteristic curve for good CS (0.837) than NCCT ASPECTS (0.802) or MTT ASPECTS (0.752) at arrival. Conclusions: Favorable CBV ASPECTS, NCCT ASPECTS and MTT ASPECTS are associated with good CS along with more salvageable tissue and longer time from the onset of symptoms to imaging in ischemic stroke patients treated with intravenous thrombolysis.

The association of blood pressure and collateral circulation in hyperacute ischemic stroke patients treated with intravenous thrombolysis.

Background: The integrity of collateral circulation is a major prognostic factor in ischemic stroke. Patients with good collateral status have larger penumbra and respond better to intravenous thrombolytic therapy. High systolic blood pressure is linked with worse clinical outcome in patients with acute ischemic stroke treated with intravenous thrombolytic therapy. We studied the effect of different blood pressure parameters on leptomeningeal collateral circulation in patients treated with intravenous thrombolytic therapy (<3 h) in a retrospective cohort. Methods: Anterior circulation thrombus was detected with computed tomography angiography and blood pressure was measured prior to intravenous thrombolytic therapy in 104 patients. Baseline clinical and imaging information were collected. Group comparisons were performed; Collateral Score (CS) was assessed and entered into logistic regression analysis. Results: Fifty-eight patients out of 104 displayed good collateral filling (CS ≥2). Poor CS was associated with more severe strokes according to National Institutes of Health Stroke Scale (NIHSS) at arrival (16 vs. 11, p = 0.005) and at 24 h (15 vs. 3, p < 0.001) after the treatment. Good CS was associated with higher systolic blood pressure (p = 0.03), but not with diastolic blood pressure (p = 0.26), pulse pressure (p = 0.20) or mean arterial pressure (p = 0.07). Good CS was associated with better Alberta Stroke Program Early CT Score (ASPECTS) in 24 h follow-up imaging (p < 0.001) and favorable clinical outcome at three months (mRS ≤2, p < 0.001). Median CS was the highest (CS = 3) when systolic blood pressure was between 170 and 190 mm Hg (p = 0.03). There was no significant difference in the number of patients with good (n = 11) and poor (n = 12) CS who received intravenous antihypertensive medication (p = 0.39) before or during the thrombolytic therapy. In multivariate analysis age (p = 0.02, OR 0.957 per year, 95% CI 0.92-0.99), time from the onset of symptoms to treatment (p = 0.005, OR 1.03 per minute, 95% CI 1.01-1.05), distal clot location (p = 0.02, OR 3.52, 95% CI 1.19-10.35) and systolic blood pressure (p = 0.04, OR 1.03 per unit mm Hg, 95% CI 1.00-1.05) predicted good CS. Higher systolic blood pressure (p = 0.049, OR 0.96 per unit mm Hg, 95% CI 0.93-1.00) and pulse pressure (p = 0.005, OR 0.94 per unit mm Hg, 95% CI 0.90-0.98) predicted unfavorable clinical outcome at three months in multivariate analysis. Conclusion: Moderately elevated systolic blood pressure is associated with good collateral circulation in patients treated with intravenous thrombolytic therapy. However, there is an inverse association of systolic blood pressure with the three-month clinical outcome. Diastolic blood pressure, mean arterial pressure and pulse pressure are not statistically and significantly associated with collateral status.

Impact of ischemic heart disease and atrial fibrillation on survival after spontaneous intracerebral hemorrhage

OBJECT The well-known predictors for increased early deaths after spontaneous intracerebral hemorrhage (ICH) include the clinical and radiological severity of bleeding as well as being on a warfarin regimen at the onset of stroke. Ischemic heart disease and atrial fibrillation may also increase early deaths. In the present study the authors aimed to elucidate the role of the last 2 factors. METHODS The authors assessed the 3-month mortality rate in patients with spontaneous ICH (453 individuals) who were admitted to the stroke unit of Oulu University Hospital within a period of 11 years (1993-2004). RESULTS The 3-month mortality rate for the 453 patients was 28%. The corresponding mortality rates were 42% for the patients who had ischemic heart disease and 61% for those with atrial fibrillation on admission. The following independent predictors of death emerged after adjustment for sex and the use of warfarin or aspirin at the onset of ICH: 1) ischemic heart disease (hazard ratio [HR] 1.67, 95% confidence interval [CI] 1.12-2.48, p < 0.02); 2) atrial fibrillation on admission (HR 1.79, 95% CI 1.12-2.86, p < 0.02); 3) the Glasgow Coma Scale score on admission (HR 0.82 per unit, 95% CI 0.79-0.87, p < 0.01); 4) size of hematoma (HR 1.11 per 10 ml, 95% CI 1.07-1.16, p < 0.01); 5) intraventricular hemorrhage (HR 2.62, 95% CI 1.71-4.02, p < 0.01); 6) age (HR 1.04 per year, 95% CI 1.02-1.06, p < 0.01); and 7) infratentorial location of the hematoma (HR 1.93, 95% CI 1.26-2.97, p < 0.01). CONCLUSIONS Both ischemic heart disease and atrial fibrillation independently and significantly impaired the 3-month survival of patients with ICH.

Lambert-Eaton myasthenic syndrome following H1N1-influenza vaccination: a case report.

The outbreak of influenza A (H1N1) pandemic during the year 2009 led to the development of several vaccinations against H1N1 virus. In Finland, 2.6 million citizens were vaccinated during pandemic 2009 – 2010 with adjuvanted influenza vaccine, Pandemrix®.

Computed tomography angiography source images closely reflect the integrity of collateral circulation.

BACKGROUND We studied the interplay between collateral circulation, the location of the thrombus and infarct extent based on evaluation of CT angiography source images (CTA-SI) in predicting the clinical outcome of patients treated with intravenous thrombolytic therapy (<3h) in a retrospective cohort. METHODS Anterior circulation occlusion was detected with CTA in 105 patients. The site of the occlusion was recorded, collaterals were assessed with Collateral Score (CS) and Alberta Stroke Program Early CT Score (ASPECTS) was evaluated from CTA-SI, and entered into logistic regression analysis to predict favorable clinical outcome (three-month modified Rankin Scale 0-2). RESULTS CTA-SI ASPECTS was highly correlated with CS (Spearmans rho=0.63, P=0.01). Not a single patient with good collaterals (CS 2-4) had a poor CTA-SI scan (ASPECTS 0-7). The mean CTA-SI ASPECTS score became progressively lower when the status of the collateral circulation deteriorated (ANOVA P<0.001). In univariate analysis a good CTA-SI scan at the admission predicted favorable three-month outcome (P<0.001). In a multivariate model containing CTA-SI ASPECTS, CS and the site of the occlusion along with significant clinical parameters, CTA-SI ASPECTS was rendered non-significant (P=0.43) in the presence of CS. CONCLUSIONS CTA-SI and CS convey overlapping information. CTA-SI is not a significant predictor of the clinical outcome three months after intravenous thrombolysis when the other CTA-based parameters, CS and the clot location, are considered simultaneously. CTA-SI may have a role in the assessment of the extent of irreversible ischemic changes at admission if contrast injection and image acquisition protocols are designed suitably.