Endothelial nitric oxide synthase is not essential for the development of fibrosis and portal hypertension in bile duct ligated mice

BACKGROUND/AIMS: It is postulated that nitric oxide (NO) is responsible for the hyperdynamic circulation of portal hypertension. Therefore, we investigated induction of fibrosis and hyperdynamic circulation in endothelial NO synthase knock-out (KO) mice. METHODS: Fibrosis was induced by bile duct ligation. Hemodynamic studies were performed after portal vein ligation. All studies were performed in wild-type (WT) and KO mice. RESULTS: Three to 4 weeks after bile duct ligation (BDL), both WT and KO groups had similar degrees of portal hypertension, 12 (9-14) and 11(8-15) mmHg, median (range), and liver function. Fibrosis increased from 0.0% in sham operated to 1.0 and 1.1% in WT and KO mice, respectively. Cardiac output was similar after portal vein ligation (20 and 17 ml/min in WT and KO mice, respectively). There was no difference in liver of mRNA for endothelin 1, inducible NO synthase (iNOS) and hem-oxygenase 1 (HO1); proteins of iNOS, HO1 and HO2; nor in endothelin A and B (EtA and EtB) receptor density between WT and KO mice after BDL. CONCLUSIONS: These results suggest that endothelial NO synthase is neither essential for the development of fibrosis and portal hypertension in bile duct ligated mice, nor for the hyperdynamic circulation associated with portal hypertension in the portal vein ligated mice.

Intra-arterial thrombolysis of acute iatrogenic intracranial arterial occlusion attributable to neuroendovascular procedures or coronary angiography

BACKGROUND AND PURPOSE: For selected stroke patients, intra-arterial thrombolysis (IAT) has been shown to be an effective treatment option. However, knowledge of safety and efficacy of IAT in patients with acute stroke as a complication of arterial catheter interventions is limited. METHODS: We analyzed clinical radiological findings and functional outcomes in consecutive patients 3 months after treatment with IAT for peri-procedural strokes occurring during neuroendovascular or cardiac catheter interventions. To measure outcome, the modified Rankin scale score was used. RESULTS: Of a total of 432 patients treated with IAT, 12 (4 women and 8 men; mean age, 60 years) were treated because of an ischemic stroke after a neuro-endovascular procedure (n=6) or coronary angiography (n=6). The median baseline National Institutes of Health Stroke Scale score was 15. Recanalization was complete (thrombolysis in myocardial infarction grade 3) in 6, partial (thrombolysis in myocardial infarction 2) in 5, and minimal (thrombolysis in myocardial infarction 1) in 1. Nine patients (75%) had a favorable outcome (modified Rankin scale score, 0 to 2), and 3 had a poor outcome (modified Rankin scale score, 3 or 4). All patients with complete recanalization had a favorable outcome, whereas only 3 of 6 patients with partial or minimal recanalization (P=0.18) had a favorable outcome. Follow-up brain imaging was normal in 2 and showed new ischemic lesions in 10 patients. Two patients (17%) had a symptomatic intracerebral hemorrhage. CONCLUSIONS: In acute stroke attributable to arterial catheter interventions, IAT is feasible and has the potential to improve outcome in these patients. A high recanalization rate could be achieved.

Brain edema and increased intracranial pressure in the pathophysiology of bacterial meningitis

A number of advances in our understanding of the pathophysiology of bacterial meningitis have been made in recent years. In vivo studies have shown that bacterial cell wall fragments and endotoxins are highly active components, independent of the presence of viable bacteria in the subarachnoid space. Their presence in the cerebrospinal fluid is associated with the induction of inflammation and with the development of brain edema and increased intracranial pressure. Antimicrobial therapy may cause an additional increase of harmful bacterial products in the cerebrospinal fluid and thereby potentiate these pathophysiological alterations. These changes may contribute to the development of brain damage during meningitis. Some promising experimental work has been directed toward counteracting the above phenomena with non-steroidal or steroidal anti-inflammatory agents as well as with monoclonal antibodies. Although considerable advances have been made, further research needs to be done in these areas to improve the prognosis of bacterial meningitis.

Influence of granulocytes on brain edema, intracranial pressure, and cerebrospinal fluid concentrations of lactate and protein in experimental meningitis

Brain water content (brain edema), intracranial pressure, and cerebrospinal fluid (CSF) concentrations of lactate and protein increased significantly during 24 h of experimental meningitis due to Streptococcus pneumoniae, but changes were similar in normal and neutropenic rabbits. In sterile meningitis induced by N-formyl-methionyl-leucyl-phenyl-alanine (fMLP), low and high doses of fMLP were equally effective in inducing CSF pleocytosis, whereas only high doses of fMLP caused brain edema. High doses of fMLP injected intracisternally during pneumococcal meningitis also increased brain water content. The fMLP did not significantly increase intracranial pressure or CSF concentrations of lactate or protein in sterile or pneumococcal meningitis, nor did it cause brain edema in neutropenic animals. Thus, granulocytes may contribute to brain edema during meningitis if adequately stimulated, but intracranial pressure and CSF protein and lactate concentrations appear independent of granulocytes. Stimulation does not appear to occur early in meningitis, when granulocytes were without effect on brain edema.

Stent placement in the endovascular treatment of intracranial aneurysms

To analyze the immediate and midterm angiographic and clinical results of stent placement in the endovascular treatment of intracranial cerebral aneurysms.

Abciximab for thrombolysis during intracranial aneurysm coiling

INTRODUCTION: Thrombotic events are a common and severe complication of endovascular aneurysm treatment with significant impact on patients' outcome. This study evaluates risk factors for thrombus formation and assesses the efficacy and safety of abciximab for clot dissolution. MATERIALS AND METHODS: All patients treated with abciximab during (41 patients) or shortly after (22 patients) intracranial aneurysm coil embolisation were retrieved from the institutional database (2000 to 2007, 1,250 patients). Sixty-three patients (mean age, 55.3 years, +/-12.8) had received either intra-arterial or intravenous abciximab. Risk factors for clot formation were assessed and the angiographic and clinical outcome evaluated. RESULTS: No aneurysm rupture occurred during or after abciximab application. The intra-procedural rate of total recanalisation was 68.3%. Thromboembolic complications were frequently found in aneurysms of the Acom complex and of the basilar artery, whilst internal carotid artery aneurysms were underrepresented. Two patients died of treatment-related intracranial haemorrhages into preexisting cerebral infarcts. Two patients developed a symptomatic groin haematoma. CONCLUSIONS: Abciximab is efficacious and safe for thrombolysis during and after endovascular intracranial aneurysm treatment in the absence of preexisting ischaemic stroke.

Efficacy of the combination of amlodipine and valsartan in patients with hypertension uncontrolled with previous monotherapy: the Exforge in Failure after Single Therapy (EX-FAST) study

In this randomized, double-blind, multicenter study, patients whose blood pressure (BP) was uncontrolled by monotherapy were switched directly to amlodipine/valsartan 5/160 mg (n=443) or 10/160 mg (n=451). After 16 weeks, BP control (levels <140/90 mm Hg or <130/80 mm Hg for diabetics) was achieved in 72.7% (95% confidence interval [CI], 68.6-76.9) of patients receiving amlodipine/valsartan 5/160 mg and in 74.8% (95% CI, 70.8-78.9) receiving amlodipine/valsartan 10/160 mg. Incremental reductions from baseline in mean sitting systolic and diastolic BP were significantly greater with the higher dose (20.0+/-0.7 vs 17.5+/-0.7 mm Hg; P=.0003 and 11.6+/-0.4 vs 10.4+/-0.4 mm Hg; P=.0046). Incremental BP reductions were also achieved with both regimens irrespective of previous monotherapy, hypertension severity, diabetic status, body mass index, and age. Peripheral edema was the most frequent adverse event. These results provide support for the BP-lowering benefits of complementary antihypertensive therapy with amlodipine and valsartan in patients with hypertension uncontrolled by previous monotherapy.

Prior statin use, intracranial hemorrhage, and outcome after intra-arterial thrombolysis for acute ischemic stroke

BACKGROUND AND PURPOSE: There are only limited data on whether prior statin use and/or cholesterol levels are associated with intracranial hemorrhage (ICH) and outcome after intra-arterial thrombolysis. The purpose of this study was to evaluate the association of statin pretreatment and cholesterol levels with the overall frequency of ICH, the frequency of symptomatic ICH, and clinical outcome at 3 months. METHODS: We analyzed 311 consecutive patients (mean age, 63 years; 43% women) who received intra-arterial thrombolysis. RESULTS: Statin pretreatment was present in 18%. The frequency of any ICH was 20.6% and of symptomatic ICH 4.8%. Patients with any ICH were more often taking statins (30% versus 15%, P=0.005), more often had atrial fibrillation (45% versus 30%, P=0.016), had more severe strokes (mean National Institute of Health Stroke Scale score 16.5 versus 14.7, P=0.022), and less often good collaterals (16% versus 24%, P=0.001). Patients with symptomatic ICH were more often taking statins (40% versus 15%, P=0.009) and had less often good collaterals (0% versus 24%, P<0.001). Any ICH or symptomatic ICH were not associated with cholesterol levels. After multivariate analysis, the frequency of any ICH remained independently associated with previous statin use (OR, 3.1; 95% CI, 1.53 to 6.39; P=0.004), atrial fibrillation (OR, 2.5; CI, 1.35 to 4.75; P=0.004), National Institutes of Health Stroke Scale score (OR, 1.1; CI, 1.00 to 1.10; P=0.037), and worse collaterals (OR, 1.7; CI, 1.19 to 2.42; P=0.004). There was no association of outcome with prior statin use, total cholesterol level, or low-density lipoprotein cholesterol level. CONCLUSIONS: Prior statin use, but not cholesterol levels on admission, is associated with a higher frequency of any ICH after intra-arterial thrombolysis without impact on outcome.

Stent placement in acute cerebral artery occlusion: use of a self-expandable intracranial stent for acute stroke treatment

Stent placement has been applied in small case series as a rescue therapy in combination with different thrombolytic agents, percutaneous balloon angioplasty (PTA), and mechanical thromboembolectomy (MT) in acute stroke treatment. These studies report a considerable mortality and a high rate of intracranial hemorrhages when balloon-mounted stents were used. This study was performed to evaluate feasibility, efficacy, and safety of intracranial artery recanalization for acute ischemic stroke using a self-expandable stent.

Normobaric hyperoxia--induced improvement in cerebral metabolism and reduction in intracranial pressure in patients with severe head injury: a prospective historical cohort-matched study

OBJECT: The effect of normobaric hyperoxia (fraction of inspired O2 [FIO2] concentration 100%) in the treatment of patients with traumatic brain injury (TBI) remains controversial. The aim of this study was to investigate the effects of normobaric hyperoxia on five cerebral metabolic indices, which have putative prognostic significance following TBI in humans. METHODS: At two independent neurointensive care units, the authors performed a prospective study of 52 patients with severe TBI who were treated for 24 hours with 100% FIO2, starting within 6 hours of admission. Data for these patients were compared with data for a cohort of 112 patients who were treated in the past; patients in the historical control group matched the patients in our study according to their Glasgow Coma Scale scores after resuscitation and their intracranial pressure within the first 8 hours after admission. Patients were monitored with the aid of intracerebral microdialysis and tissue O2 probes. Normobaric hyperoxia treatment resulted in a significant improvement in biochemical markers in the brain compared with the baseline measures for patients treated in our study (patients acting as their own controls) and also compared with findings from the historical control group. In the dialysate the glucose levels increased (369.02 +/- 20.1 micromol/L in the control group and 466.9 +/- 20.39 micromol/L in the 100% O2 group, p = 0.001), whereas the glutamate and lactate levels significantly decreased (p < 0.005). There were also reductions in the lactate/glucose and lactate/pyruvate ratios. Intracranial pressure in the treatment group was reduced significantly both during and after hyperoxia treatment compared with the control groups (15.03 +/- 0.8 mm Hg in the control group and 12.13 +/- 0.75 mm Hg in the 100% O2 group, p < 0.005) with no changes in cerebral perfusion pressure. Outcomes of the patients in the treatment group improved. CONCLUSIONS: The results of the study support the hypothesis that normobaric hyperoxia in patients with severe TBI improves the indices of brain oxidative metabolism. Based on these data further mechanistic studies and a prospective randomized controlled trial are warranted.