Optimizing the Definition of Ischemic Core in CT Perfusion: Influence of Infarct Growth and Tissue-Specific Thresholds.

BACKGROUND AND PURPOSE: CTP allows estimating ischemic core in patients with acute stroke. However, these estimations have limited accuracy compared with MR imaging. We studied the effect of applying WM- and GM-specific thresholds and analyzed the infarct growth from baseline imaging to reperfusion. MATERIALS AND METHODS: This was a single-center cohort of consecutive patients (n = 113) with witnessed strokes due to proximal carotid territory occlusions with baseline CT perfusion, complete reperfusion, and follow-up DWI. We segmented GM and WM, coregistered CTP with DWI, and compared the accuracy of the different predictions for each voxel on DWI through receiver operating characteristic analysis. We assessed the yield of different relative CBF thresholds to predict the final infarct volume and an estimated infarct growth-corrected volume (subtracting the infarct growth from baseline imaging to complete reperfusion) for a single relative CBF threshold and GM- and WM-specific thresholds. RESULTS: The fixed threshold underestimated lesions in GM and overestimated them in WM. Double GM- and WM-specific thresholds of relative CBF were superior to fixed thresholds in predicting infarcted voxels. The closest estimations of the infarct on DWI were based on a relative CBF of 25% for a single threshold, 35% for GM, and 20% for WM, and they decreased when correcting for infarct growth: 20% for a single threshold, 25% for GM, and 15% for WM. The combination of 25% for GM and 15% for WM yielded the best prediction. CONCLUSIONS: GM- and WM-specific thresholds result in different estimations of ischemic core in CTP and increase the global accuracy. More restrictive thresholds better estimate the actual extent of the infarcted tissue.

Leukoaraiosis May Confound the Interpretation of CT Perfusion in Patients Treated with Mechanical Thrombectomy for Acute Ischemic Stroke.

BACKGROUND AND PURPOSE: Leukoaraiosis frequently coexists in patients with acute stroke. We studied whether leukoaraiosis could confound the interpretation of CTP findings in patients treated with mechanical thrombectomy. MATERIALS AND METHODS: We analyzed 236 patients with stroke treated with mechanical thrombectomy and studied with CTP, of whom 127 (53.8%) achieved complete reperfusion. Periventricular white matter hyperintensities on MR imaging and hypodensities on NCCT were assessed through the Fazekas score. CTP-predicted nonviable tissue was defined as relative CBF <30%, and final infarct volume was quantified in DWI. We estimated mean MTT, CBV, and CBF in the asymptomatic hemisphere. In patients achieving complete reperfusion, we assessed the accuracy of nonviable tissue to predict final infarct volume using the intraclass correlation coefficient across periventricular hyperintensity/hypodensity Fazekas scores and variable relative CBF cutoffs. RESULTS: MTT was longer (Spearman ρ = 0.279, P < .001) and CBF was lower (ρ = -0.263, P < .001) as the periventricular hyperintensity Fazekas score increased, while CBV was similar across groups (ρ = -0.043, P = .513). In the subgroup of patients achieving complete reperfusion, nonviable tissue-final infarct volume reliability was excellent in patients with periventricular hyperintensity Fazekas score grade 0 (intraclass correlation coefficient, 0.900; 95% CI, 0.805-0.950), fair in patients with periventricular hyperintensity Fazekas scores 1 (intraclass correlation coefficient, 0.569; 95% CI, 0.327-0.741) and 2 (intraclass correlation coefficient, 0.444; 95% CI, 0.165-0.657), and poor in patients with periventricular hyperintensity Fazekas score 3 (intraclass correlation coefficient, 0.310; 95% CI, -0.359-0.769). The most accurate cutoffs were relative CBF <30% for periventricular hyperintensity Fazekas score grades 0 and 1, relative CBF <25% for periventricular hyperintensity Fazekas score 2, and relative CBF <20% for periventricular hyperintensity Fazekas score 3. The reliability analysis according to periventricular hypodensity Fazekas score grades on NCCT was similar to that in follow-up MR imaging. CONCLUSIONS: In patients with stroke, the presence of leukoaraiosis confounds the interpretation of CTP despite proper adjustment of CBF thresholds.

Viabilidad y eficacia de una estrategia multidimensional para fomentar la actividad física en pacientes con ictus agudo / Feasibility and efficacy of a multidimensional strategy to promote physical activity in acute stroke patients

Objetivo: Describir la viabilidad, la seguridad y la eficacia de un enfoque multidimensional para fomentar la actividad física precoz después de un ictus isquémico. Materiales y métodos: Estudio de casos y controles que compara los resultados en los pacientes ingresados en la unidad de ictus antes y después de establecer un protocolo de fomento de la actividad física mediante la incorporación de un ejercicio aeróbico usando un cicloergómetro, y la facilitación de información verbal y escrita sobre los beneficios de la actividad física. La medida principal del estudio fue la actividad física realizada a los 3 meses usando el International Physical Activity Questionnaire. Resultados: Incluimos 93 pacientes (60 controles y 33 en el grupo activo). La actividad física previa al ictus era baja. Las 126 sesiones de cicloergómetro se toleraron bien. A los 3 meses del ictus, la actividad física fue mayor (693 vs. 462 MET-min/semana; p=0,039) y el tiempo de sedestación, menor (2.100 vs. 2.520min; p=0,009) en el grupo activo. Conclusiones: A pesar de un conocimiento apropiado de los beneficios del ejercicio sobre la salud, la actividad física es baja después del ictus. Un enfoque multidisciplinar, combinando ejercicio precoz e información individualizada, puede incrementarla

Objective: To describe the feasibility, safety, and efficacy of a multidimensional approach to promote physical activity soon after ischaemic stroke. Materials and methods: Case-control study comparing the outcomes in consecutive patients admitted to a stroke unit before and after implementing a physical activity promotion protocol by performing aerobic exercise using a cycle ergometer, and informing them on the benefits of physical activity. The primary outcome measurement was physical activity at 3 months using the International Physical Activity Questionnaire. Results: A total of 93 patients were included (60 controls and 33 in the active group). Pre-stroke activity was low. A total of 126 cycle ergometer sessions were well tolerated. At 3 months, post-stroke physical activity was greater (693 vs. 462 MET-min/week; P=.039) and sedentary time shorter (2,100 vs. 2,520min; P=.009) in the active group. Conclusions: Despite proper knowledge of the health benefits of exercise, physical activity is low after stroke. A multidisciplinary approach combining early exercise and individualised information on its benefits may increase physical activity after stroke

The I/D polymorphism of the ACE1 gene is not associated with ischaemic stroke in Spanish individuals.

BACKGROUND: The angiotensin-converting enzyme 1 (ACE1) gene has been extensively studied in stroke, yet generating conflicting results. The goal of our study was thus to clarify the influence of the ACE1 on the risk of suffering an ischaemic stroke (IS). METHODS: We genotyped the rs4341 (in linkage disequilibrium with the I/D polymorphism) of the ACE1 gene in 531 patients with IS and 549 healthy controls, and the rs1799752 (I/D polymorphism) in a subset of 68 patients with IS and 27 controls. We also performed functional studies by measuring serum ACE protein levels and enzymatic activity in 27 controls, 68 patients with IS at baseline and 35 patients with IS 24 h after onset of stroke symptoms. RESULTS: There was no association of the ACE1 variant with IS, although it affected ACE protein levels (P = 0.001). Indeed, patients with IS showed lower ACE levels than controls in the acute phase (115.9 } 38.9 vs. 174.1 } 56.1 ng/ml, P < 0.001), but not in the chronic phase (168.2 } 51.2, P = 0.673), and ACE protein levels did not differ between IS etiologies. Similar results were found for ACE activity. CONCLUSIONS: The D allele of the ACE1 I/D and ACE protein levels was not associated with a higher risk of IS in Spanish individuals.

Influence of antiplatelet pre-treatment on the risk of symptomatic intracranial haemorrhage after intravenous thrombolysis.

BACKGROUND: The influence of antiplatelet agents (AP) in the development of a symptomatic intracranial haemorrhage (SICH) after intravenous rt-PA is not well known. We assessed the hypothesis that pre-treatment with AP may increase that risk. METHODS: We studied data from consecutive patients with ischaemic stroke treated with intravenous rt-PA within the first 3 h after symptom onset. We recorded the antecedent of any AP therapy previous to thrombolysis. A follow-up CT was performed routinely 24-36 h after the infusion of rt-PA. Intracranial bleeding was categorized according to the criteria of the European Cooperative Acute Stroke Study II (ECASS II) into haemorrhagic infarction type 1 and 2 and parenchymal haemorrhage type 1 and 2. SICH was diagnosed if it was of the parenchymal haemorrhage type, occurred within the first 36 h and was associated with neurological deterioration. RESULTS: Of a total of 605 patients, 137 (22.6%) were pre-treated with AP, most of them (n = 106) with aspirin. Any type of intracranial haemorrhage was observed in 119 patients (19.7%), without differences between the AP (18.4%) and the non-AP (20.2%) groups. Parenchymal haemorrhage was observed in 41 patients (8.5%) and SICH in 26 (4.3%). There was a non-significant rise in the frequency of SICH in the AP group compared with the non-AP group (6.6 vs. 3.6% p = 0.10). CONCLUSIONS: Pre-treatment with AP non-significantly increases the risk of SICH and therefore this antecedent should not be a contraindication for intravenous thrombolysis.

The response to IV rt-PA in very old stroke patients.

The use of rtPA in stroke patients aged >80 years remains controversial and it is debated whether there are sex-based differences in the response to rtPA. We assessed the clinical value of thrombolytic therapy in patients aged >80 years (elderly group) in comparison with a non-elderly group, and evaluated the existence of sex differences in the response to rtPA. All consecutive patients (n = 157) treated with rtPA were prospectively assessed since July 2001, including 49 elderly patients who fulfilled the National Institute of Neurological Disorders and Stroke (NINDS) criteria. Changes of the National Institute of Health Stroke Scale (NIHSS) score at 1 h, 24 h, and 7 days after rtPA administration, favourable outcome at day 90 [(modified Rankin Scale) mRS 0-1, or 2 if mRS = 2 before the stroke], symptomatic bleedings, and death rates were compared between elderly and non-elderly patients. Using logistic regression, baseline NIHSS score [odds ratio (OR) 0.59, 95% confidence interval (CI) 0.41-0.84] was an independent predictor of favourable outcome, but not sex (OR 0.72, 95% CI 0.33-1.56), or age >80 years (OR 0.74, 95% CI 0.32-1.70). The rates of clinical improvement, mortality, or symptomatic CNS bleeding were also unrelated to age and sex. In conclusion, the response to IV rtPA is not impaired in elderly stroke patients and male and female are equally responsive.

The BC genotype of the VNTR polymorphism of platelet glycoprotein Ibalpha is overrepresented in patients with recurrent stroke regardless of aspirin therapy.

BACKGROUND: The contribution of genetic factors to aspirin treatment failure (ATF) for secondary prevention is not settled in patients with ischemic stroke. METHODS: We assessed the polymorphisms VNTR (A, B, C, D) of glycoprotein (GP) Ibalpha, 807C/T of GP Ia/IIa, and Pl(A1/A2) of GP IIb/IIIa, and the 5-year incidence of major recurrent events in 82 stroke patients with no major sources of cardioembolism (mean age 70, SD 9.0 years; female gender 23%). Using a structured interview, all participants confirmed good compliance with aspirin (100-300 mg/day) for secondary prevention. Demographics and atherothrombotic risk factors assessed included diabetes, hypertension, dyslipemia, smoking, and coronary heart disease. RESULTS: Thirty-one stroke patients had one recurrent stroke or myocardial infarction within 33 (7-48) months of aspirin onset, while 51 patients demonstrated an uneventful clinical course. Female gender (p < 0.05), diabetes (p < 0.05), dyslipemia (p < 0.05), and the BC genotype of VNTR (25.8 vs. 7.8%, p < 0.05) were more prevalent in patients in whom aspirin failed to prevent clinical events than in those in whom it did not. The BC genotype of VNTR was the only factor that remained associated with ATF in an age-, sex-, and risk factor-adjusted logistic regression analysis (OR 9.6, 95% CI 1.5-61.0). CONCLUSION: The BC genotype of the VNTR polymorphism of GP Ibalpha is an independent predictor of recurrent events in stroke patients treated with aspirin. This finding suggests that high shear-induced platelet activation mediated by GP Ibalpha and von Willebrand factor is an important contributor to ATF in the stroke population.

Prevention of ischemic stroke: antithrombotic therapy in cardiac embolism.

Ischemic stroke secondary to cardiac disease accounts for approximately 30% of all stroke subtypes and it may be due to a large list of conditions. Stroke secondary to heart disease causes more severe deficits, higher mortality, and increased costs that other stroke subtypes. Therefore, proper identification of cardioembolic stroke is crucial for adequate selection of optimal preventive strategies. Identification of stroke prone individuals with heart disease could also have an important therapeutic impact. This manuscript reviews the interaction between the heart and brain with a particularly emphasis in the current state of older and newer antithrombotic drugs for stroke prevention in patients with atrial fibrillation. Other neuro-cardiological issues reviewed include current antithrombotic strategies in patients with a host of heart conditions which include pacemakers, acute myocardial infarction, congestive heart failure, cardiac procedures, patent foramen ovale, valve disease, endocarditis, or cardiac tumours.

Interleukin 10, monocytes and increased risk of early infection in ischaemic stroke.

BACKGROUND AND PURPOSE: The pathophysiology of stroke-associated infection (SAI) is uncertain. The cytokine profile and peripheral white cell response were assessed in patients with or without SAI. METHODS: The incidence of SAI was assessed in 110 patients with ischaemic stroke allocated antibiotic prophylaxis or placebo within 24 h of clinical onset. Peripheral white cell counts, interleukin (IL)6, tumour necrosis factor (TNF)alpha and IL10 were measured in plasma. RESULTS: 17 (15%) patients developed infection and showed time-dependent increases of total white cell count, neutrophils, monocytes, lymphocytes, IL6 and IL10, whereas TNFalpha and the TNFalpha/IL10 ratio decreased. In logistic regression, IL10 (odds ratio (OR) 1.08, 95% confidence interval (CI) 1.01 to 1.16), monocyte count (OR 1.42, 95% CI 1.08 to 1.87) and National Institute for Health Stroke Survey score on admission (OR 1.17, 95% CI 1.05 to 1.31) were independent predictors of systemic infection. CONCLUSIONS: SAI is associated with stroke severity, excessive IL10-mediated response and an increased number of circulating monocytes. These results support the finding that acute ischaemic brain injury triggers a blood-borne anti-inflammatory response that decreases the antimicrobial drive of the immune system.

Aspirin or anticoagulants in stenosis of the middle cerebral artery: A randomized trial.

BACKGROUND: We report the results of an open, randomized, multicenter trial that compared the efficacy of aspirin to oral anticoagulants (OA) for the prevention of vascular events in patients with symptomatic stenosis of the middle cerebral artery (MCA). METHODS: Participants were randomly assigned to receive 300 mg/day of aspirin or a dose of OA (target INR 2-3). The MCA stenosis was demonstrated by conventional angiography or by at least two noninvasive examinations. Patients had either transient ischemic attack or cerebral infarct (CI) attributable to the MCA stenosis within 90 days before inclusion. The primary endpoint was: nonfatal CI, nonfatal acute myocardial infarct, vascular death and major hemorrhage. The patients were followed-up for a minimum of 1 year and a maximum of 3 years. RESULTS: The study included 28 patients (14 in each treatment group); the average age was 67 +/- 9.9 years. Men constituted 68% of the patients. After a mean follow-up of 23.1 +/- 10.9 months, there were no recurrences of CI in both groups. No endpoint was reported in the aspirin group, but 2 patients in the OA group (14.3%) exhibited vascular events: 1 acute myocardial infarct and 1 intracerebral hemorrhage). However, this difference was not statistically significant (p = 0.48). CONCLUSIONS: Our study suggests that aspirin is the treatment of choice for the prevention of vascular events in patients with symptomatic MCA stenosis.

Cortical laminar necrosis related to prolonged focal status epilepticus.

Cortical laminar necrosis (CLN) is radiologically defined as high intensity cortical lesions on T1 weighted MRI images following a gyral distribution. Histopathologically, CLN is characterised by pannecrosis of the cortex involving neurones, glial cells, and blood vessels. It has been reported to be associated with hypoxia, metabolic disturbances, drugs, and infections. We present two patients who developed CLN and permanent neurological deficits after prolonged and repeated focal status epilepticus. The possible mechanisms leading to CLN in these patients are discussed, together with the implications of prompt and aggressive treatment in similar cases.

The Early Systemic Prophylaxis of Infection After Stroke study: a randomized clinical trial.

BACKGROUND AND PURPOSE: Early infection after stroke is frequent but the clinical value of antibiotic prophylaxis in acute stroke has never been explored. OBJECTIVE AND METHODS: The Early Systemic Prophylaxis of Infection After Stroke (ESPIAS) is a randomized, double-blind, placebo-controlled study of antibiotic prophylaxis in patients older than 18 years with nonseptic ischemic or hemorrhagic stroke enrolled within 24 hours from clinical onset. Interventions included intravenous levofloxacin (500 mg/100 mL/d, for 3 days) or placebo (0.9% physiological serum) in addition to optimal care. A sample size of 240 patients was calculated to identify a 15% absolute risk reduction of the primary outcome measure, which was the incidence of infection at day 7 after stroke. Secondary outcome measures were neurological outcome and mortality at day 90. RESULTS: Based on a preplanned futility analysis, the study was interrupted prematurely when 136 patients had been included. Levofloxacin and placebo patients had a cumulative rate of infection of 6% and 6% (P=0.96) at day 1; 10% and 12% (P=0.83) at day 2; 12% and 15% (P=0.66) at day 3; 16% and 19% (P=0.82) at day 7; and 30% and 33% (P=0.70), at day 90. Using logistic regression, favorable outcome at day 90 was inversely associated with baseline National Institutes of Health Stroke Scale (OR, 0.72; 95% CI, 0.59 to 0.89; P=0.002) and allocation to levofloxacin (OR, 0.19; 95% CI, 0.04 to 0.87; P=0.03). CONCLUSIONS: Prophylactic administration of levofloxacin (500 mg/100 mL/day for 3 days) is not better than optimal care for the prevention of infections in patients with acute stroke.

The -174G/C polymorphism of the interleukin 6 gene is a hallmark of lacunar stroke and not other ischemic stroke phenotypes.

BACKGROUND AND PURPOSE: The CC genotype of the -174 G/C interleukin (IL)-6 polymorphism has been associated with lacunar stroke. However, it remains unsettled whether this polymorphism is also associated with other ischemic stroke phenotypes. METHODS: The -174 G/C IL-6 polymorphism was genotyped in patients with lacunar stroke (n = 89), stroke due to large vessel disease (n = 82), cardioembolism (n = 53), stroke of undetermined cause (n = 49) and in white controls without any history of stroke (n = 105) by PCR and restriction enzyme analysis. Independent predictors of the -174 G/C IL-6 genotypes were assessed using multivariate logistic regression models adjusted for demographics, risk factors and disease state. RESULTS: The prevalence of the CC genotype was 8.5% in large vessel disease, 7.5% in embolism, 19.1% in lacunar stroke, 14.3% in stroke of undetermined cause and 8.6% in controls. The CC genotype was independently associated with lacunar stroke only (adjusted OR 3.22, 95% CI 9.09-1.12). Contrarily, there were no significant differences in genotype and allele distribution in the remainder of ischemic stroke phenotypes. Pooling of patients with nonlacunar stroke did not show any independent association with the CC genotype as compared with controls (OR 1.01, 95% CI 2.77-0.36). CONCLUSIONS: The unique association between the CC genotype of the -174 G/C IL-6 polymorphism and lacunar stroke suggests a particular susceptibility of small deep penetrators of cerebral arteries to IL-6-mediated inflammatory damage.

[Antithrombotic treatment of fusiform aneurysms of the basilar artery]. / Tratamiento antitrombótico en los aneurismas fusiformes de la arteria basilar.

Fusiform aneurysms are unusual, and they are most found in the vertebrobasilar system. Although the presence of such aneurysms has been related to atheromatous degeneration of the arterial wall, in many cases the cause of their formation is unknown. The clinical manifestations of fusiform aneurysms of the vertebrobasilar system are generally due to mass effect with compression of adjacent structures or to ischemic events; exceptionally they are due to subarachnoidal haemorrhage. We present the case of a patient with symptoms suggestive of brainstem ischemic damage, in which neuroimaging showed a fusiform aneurysm of the basilar artery with an intraaneurysmatic thrombus. Antiaggregation did not prevent new ischemic events, so anticoagulation therapy was initiated. The patient remained asymptomatic at 8 months of follow-up. The treatment of fusiform aneurysms is controversial; however, there are some evidences in the literature supporting that patients with ischemic events may be treated with long term anticoagulation, especially in cases of non-giant aneurysms of the vertebrobasilar system not accompanied by aneurysms in other sites.

Tratamiento antitrombótico en los aneurismas fusiformes de la arteria basilar / Antithrombotic treatment in the fusiform aneurysms of the basilar artery

Los aneurismas fusiformes (AF) son poco frecuentes, y se localizan principalmente en el sistema vertebrobasilar. Aunque se ha relacionado la presencia de estos aneurismas con la degeneración ateromatosa de la pared arterial, en la mayoría de casos la causa de su formación es desconocida. Las manifestaciones clínicas de los AF del sistema vertebrobasilar son generalmente debidas a fenómenos mecánicos por compresión de las estructuras adyacentes o a fenómenos isquémicos. Excepcionalmente, la clínica es debida a una hemorragia subaracnoidea. Presentamos el caso de un paciente con sintomatología sugestiva de afectación isquémica del tronco del encéfalo, en el que la neuroimagen demostró la presencia de un AF de la arteria basilar con un trombo intraaneurismático. El tratamiento antiagregante no previno la aparición de nuevos fenómenos isquémicos, por lo que se instauró un tratamiento descoagulante quedando el paciente asintomático tras 8 meses de seguimiento. El tratamiento de los AF es controvertido; sin embargo, existen algunas evidencias en la bibliografía de que los pacientes con síntomas isquémicos pueden beneficiarse de una anticoagulación mantenida, sobre todo en los casos de aneurismas no gigantes de territorio vertebrobasilar que no se acompañan de aneurismas en otras localizaciones. (AU)

Analysis of the coding and the 5' flanking regions of the alpha-synuclein gene in patients with Parkinson's disease.

Missense mutations of the alpha-synuclein gene have been reported to explain a few kindreds with autosomal dominant Parkinson's disease (PD). In order to identify mutations in our PD patients, we have screened the coding region and 5'flanking region of the gene. DNA samples from 50 patients with familial PD were screened via single-strand conformation polymorphism (SSCP) for mutations in the alpha-synuclein gene. The 5' flanking region was examined in 117 additional PD patients (27 patients with unclear family history for PD, and 90 patients without family history) and in 169 control subjects. We found one change (G199A) in exon 4 in one family with a pattern of autosomal dominant PD. However, this mutation did not result in an amino acid substitution (valine) and did not segregate completely with PD. The analysis of the 5' flanking region also showed a new polymorphism, a nucleotide insertion (- 164insA) linked to a nucleotide substitution (C-116G), in patients and in controls. The -164insA/C-116G allele was present in 52.3% of the patients and in 47.6% of the controls. We did not find significant differences regarding the allelic and genotype frequencies between PD and control groups. These results suggest that mutations in the alpha-synuclein gene are a very rare cause of familial PD and that the novel -164insA/C-116G polymorphism in the 5' flanking region does not confer susceptibility to develop PD.

alpha(1)-antichymotrypsin polymorphism: a risk factor for hemorrhagic stroke in normotensive subjects.

BACKGROUND AND PURPOSE: Although genetic factors may be important in the pathogenesis of ischemic stroke (IS), little is known on the potential role of genes in most cases of hemorrhagic stroke (HS). Preliminary data showed that the TT genotype of the alpha(1)-antichymotrypsin (ACT) gene polymorphism was associated with HS, although it remained unsettled whether prevalence of this polymorphism might differ between hypertensive and normotensive HS. METHODS: Ninety-nine patients with HS, 182 patients with IS (symptomatic control subjects), and 80 asymptomatic control subjects were genotyped for the ACT polymorphism using polymerase chain reaction amplification. Chronic hypertension was recorded in 66 patients with HS. RESULTS: The ACT-TT genotype was more prevalent in patients than in asymptomatic or symptomatic control subjects: 26%, 15%, and 16%, respectively. The ACT-TT genotype was obtained in 33% of HS who lacked arterial hypertension (P<0.05). After adjustment for age, gender, and vascular risk factors, the ACT-TT genotype remained independently associated with HS (OR 2.80, 95% CI 1.19 to 6.58, compared with asymptomatic control subjects; OR 1.79, 95% CI 0.95 to 3.40, compared with symptomatic control subjects). In analyses restricted to HS in normotensive patients, the ORs were 3.10 (95% CI 1.10 to 8.68) and 2.53 (95% CI 1.04 to 6.18), respectively. CONCLUSIONS: These findings confirm in a larger series of patients the association between the ACT-TT genotype and HS. This polymorphism is more prevalent in normotensive bleedings. Pathological studies will be required to establish whether the ACT-TT genotype facilitates proteolytic rupture of vessels that harbor amyloidotic changes or another form of nonhypertensive cerebral angiopathy.