Engineered microparticles and nanoparticles for fibrinolysis

Fibrinolytic agents including plasmin and plasminogen activators improve outcomes in acute ischemic stroke and thrombosis by recanalizing occluded vessels. In the decades since their introduction into clinical practice, several limitations of have been identified in terms of both efficacy and bleeding risk associated with these agents. Engineered nanoparticles and microparticles address some of these limitations by improving circulation time, reducing inhibition and degradation in circulation, accelerating recanalization, improving targeting to thrombotic occlusions, and reducing off-target effects; however, many particle-based approaches have only been used in preclinical studies to date. This review covers four advances in coupling fibrinolytic agents with engineered particles: (a) modifications of plasminogen activators with macromolecules, (b) encapsulation of plasminogen activators and plasmin in polymer and liposomal particles, (c) triggered release of encapsulated fibrinolytic agents and mechanical disruption of clots with ultrasound, and (d) enhancing targeting with magnetic particles and magnetic fields. Technical challenges for the translation of these approaches to the clinic are discussed.

Effectiveness and Cost of Weekly Recombinant Tissue Plasminogen Activator Hemodialysis Catheter Locking Solution

BACKGROUND AND OBJECTIVES

Evidence to guide hemodialysis catheter locking solutions is limited. We aimed to assess effectiveness and cost of recombinant tissue plasminogen activator (rt-PA) once per week as a locking solution, compared with thrice weekly citrate or heparin, in patients at high risk of complications.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We used a prospective design and pre-post comparison in three sites across Canada. Pre-post comparisons were conducted using multilevel mixed effects regression models accounting for cluster with site and potential enrollment of patients more than once. In the pre period, catheter malfunction was managed as per site-specific standard of care. The intervention in the post period was once weekly rt-PA as a locking solution (with citrate or heparin used for other sessions). The primary outcome was rate of rt-PA use for treatment of catheter malfunction. Secondary outcomes included rates of bacteremia, management of catheter malfunction, and cost.

RESULTS

There were 374 patients (mean age 68 years; 52% men) corresponding to 506 enrollments. Mean length of enrollment was 200 days (SD 119) in the pre period and 187 days (SD 101) in the post period. There was a significant decline in rate of rt-PA use for treatment of catheter malfunction in the post compared with pre period (adjusted incidence rate ratio, 0.39; 95% confidence interval, 0.30 to 0.52); however, there was no difference in the rate of bacteremia, or catheter stripping or removal/replacement. The increase in mean total health care cost in the post period was CAD$962 per enrollment, largely related to costs of rt-PA as a locking solution.

CONCLUSIONS

Once weekly rt-PA as a catheter locking solution was associated with a reduction in rt-PA use for treatment of catheter malfunction. Our results showing a reduction in rescue rt-PA use are consistent with a prior randomized trial, although we did not observe a reduction in bacteremia or catheter stripping/removal and did observe an increased incremental cost of this strategy primarily accounted for by the cost of the rt-PA.

P-selectin-targeting of the fibrin selective thrombolytic Desmodus rotundus salivary plasminogen activator α1

During thrombosis, P-selectin is expressed on the surface of activated endothelial cells and platelets. We hypothesized that targeting a plasminogen activator (PA) to P-selectin would enhance local thrombolysis and reduce bleeding risk. Previously, a urokinase (uPA)/anti-P-selectin antibody (HuSZ51) fusion protein was shown to increase fibrinolysis in a hamster pulmonary embolism model. To explore the therapeutic potential of this targeting strategy, we fused the fibrin-selective Desmodus rotundus salivary PA α1 (dsPAα1) to HuSZ51 and compared the fibrinolytic activity of P-selectin-targeted dsPAα1 (HuSZ51-dsPAα1) to unmodified dsPAα1 in vitro and in vivo. HuSZ51-dsPAα1 and dsPAα1 were expressed in CHO cells and purified to homogeneity by affinity chromatography. HuSZ51dsPAα1 bound to thrombin-activated human and dog platelets with comparable affinities to that of parental antibody SZ51. The fusion protein retained the catalytic activities of dsPAα1 in chromogenic and clot lysis assays, indicating that dsPAα1 is fully functional when fused to HuSZ51. Compared to dsPAα1, HuSZ51-dsPAα1 had similar thrombolytic efficacy in a rat pulmonary embolism model and anti-thrombotic potency in a dog model of femoral artery thrombosis. However, HuSZ51dsPAα1 was less effective in lysis of preexisting arterial thrombi in the dog model. The reduced arterial thrombolysis was not due to the pharmacokinetic properties of HuSZ51-dsPAα1 because antigen level and amidolytic activity were higher in plasma from HuSZ51-dsPAα1-treated groups than corresponding dsPAα1-treated groups. These data indicate that the thrombolytic efficacy of HuSZ51-dsPAα1 varied dependent on the physical composition of thrombi. The lack of stimulation by fibrin in arterial thrombi may contribute to the attenuated thrombolytic efficacy of HuSZ51-dsPAα1 in the dog model.

Encapsulation of a plasminogen activator speeds reperfusion, lessens infarct and reduces blood loss in a canine model of coronary artery thrombosis

In the present study, a polymer-encapsulated plasminogen activator was investigated as an alternative to restore blood flow more effectively than free plasminogen activator. While current fibrinolytic agents have limited efficacy, attributable to delayed onset of sustained reperfusion and bleeding complications, encapsulated plasminogen activators have shown promise in addressing these shortcomings. A polymer-encapsulated plasminogen activator could offer an effective formulation with a prolonged shelf-life. In this study, coronary artery thrombosis was produced in the anesthetized dog by the injection of thrombin + whole blood, and then one of five randomly selected formulations was administered intravenously: saline, blank microcapsules, free streptokinase (FREE SK), streptokinase and blank microcapsules (FREE SK + BLANK), or streptokinase entrapped in polymer microcapsules (MESK). MESK significantly accelerated the time to reperfusion compared to FREE SK or FREE SK + BLANK. Additionally, substantial reductions were observed in residual clot mass, infarct mass, reocclusion episodes, fibrinogen depletion and blood loss with MESK compared to FREE SK. The results of this study demonstrate that MESK accelerates thrombolysis and the restoration of blood flow compared to identical dosages of FREE SK while also reducing systemic fibrinogenolysis and blood loss. Microencapsulation may produce an improved dosage form for restoring arterial blood flow and reducing bleeding complications with thrombolytic therapy.

Efficacy and safety of desmoteplase in acute ischemic stroke patients: A systematic review and meta-analysis

BACKGROUND

Pending results from double-blind, multicenter, parallel-group, randomized trials, the benefit and safety of the novel plasminogen activator, desmoteplase remain undetermined. The aim of this meta-analysis was to help evaluate desmoteplase's efficacy and safety.

METHODS

A thorough search was performed of the Cochrane Library, PubMed, and Embase from the inception of electronic data to March 2017, and double-blind, multicenter, parallel-group, randomized trials were chosen. We conducted a meta-analysis of studies investigating intravenous desmoteplase treatment of acute ischemic stroke patients 3 to 9 hours after symptom onset. Asymptomatic intracerebral hemorrhage, good clinical outcome at 90 days, and reperfusion 4 to 8 hours posttreatment were variables assessing efficacy; symptomatic intracerebral hemorrhage and death rates were measures of safety.

RESULTS

Six trials involving 1071 patients thrombolyzed >3 hours postonset were included (600 received intravenous desmoteplase, 471 placebo). Desmoteplase was associated with increased reperfusion (odds ratio [OR] 1.57; 95% confidence interval [CI], 1.10-2.24; P = .01 vs control) and showed a tendency to increase asymptomatic intracerebral hemorrhage (OR 1.25; 95% CI, 0.97-1.62; P = .09 vs control), whereas there was no increase in symptomatic intracerebral hemorrhage and death rate with desmoteplase. However, there was no difference in the clinical response at 90 days (OR 1.14; 95% CI, 0.88-1.49; P = .31 vs control). Subgroup analysis showed that desmoteplase 90 μg/kg (OR 1.53; 95% CI, 1.07-2.21; P = .02 vs control) and 125 μg/kg (OR 4.07; 95% CI, 1.16-14.24; P = .03 vs control) were associated with an increase in reperfusion. Also, we found desmoteplase 90 μg/kg showed a tendency to increase asymptomatic intracerebral hemorrhage (OR 1.25; 95% CI, 0.95-1.63; P = .11 vs control).

CONCLUSION

Intravenous desmoteplase is associated with a favorable reperfusion efficacy and acceptable safety in ischemic stroke treatment >3 hours after symptom onset. Well-designed randomized controlled trials with larger patient cohorts and a moderate dose of drugs are needed to further evaluate the true efficacy of desmoteplase in stroke patients.

TRIAL REGISTRATION

URL: http://www.crd.york.ac.uk/PROSPERO; PROSPERO registration number: CRD42016037667).

[Cerebral infarction due to cardiac myxoma developed with the loss of consciousness immediately after defecation-a case report]

A 74-year-old man lost consciousness immediately after defecation. The loss of consciousness lasted for several minutes, and he experienced difficulty in walking when he regained consciousness. He was transferred to our hospital via an ambulance. Upon neurological examination, nystagmus and ataxia in the left arm and leg were noted. An MRI of the brain revealed multiple acute infarcts mainly in the bilateral cerebellum. Intravenous thrombolytic therapy with alteplase was initiated 3 h and 20 min after the onset of symptoms, and an improvement in neurological symptoms was observed. Echocardiography displayed a mobile mass in the left atrium, suggesting myxoma. After 14 days from the onset of symptoms, the tumor was surgically resected, and a pathological diagnosis of myxoma was established. Because of the unique event surrounding the onset in this case, we considered that there was a potential detachment of myxoma and/or thrombi fragments triggered by an increase in intrathoracic pressure induced by the action of defecation. This present case suggests that clinicians should consider cardiac myxoma in patients with cerebral infarction if the stroke is preceded by a Valsalva maneuver-like action and accompanied by the loss of consciousness.

Complement Activation in Arterial and Venous Thrombosis is Mediated by Plasmin

Thrombus formation leading to vaso-occlusive events is a major cause of death, and involves complex interactions between coagulation, fibrinolytic and innate immune systems. Leukocyte recruitment is a key step, mediated partly by chemotactic complement activation factors C3a and C5a. However, mechanisms mediating C3a/C5a generation during thrombosis have not been studied. In a murine venous thrombosis model, levels of thrombin–antithrombin complexes poorly correlated with C3a and C5a, excluding a central role for thrombin in C3a/C5a production. However, clot weight strongly correlated with C5a, suggesting processes triggered during thrombosis promote C5a generation. Since thrombosis elicits fibrinolysis, we hypothesized that plasmin activates C5 during thrombosis. In vitro, the catalytic efficiency of plasmin-mediated C5a generation greatly exceeded that of thrombin or factor Xa, but was similar to the recognized complement C5 convertases. Plasmin-activated C5 yielded a functional membrane attack complex (MAC). In an arterial thrombosis model, plasminogen activator administration increased C5a levels. Overall, these findings suggest plasmin bridges thrombosis and the immune response by liberating C5a and inducing MAC assembly. These new insights may lead to the development of strategies to limit thrombus formation and/or enhance resolution.

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Thrombin is not a major direct contributor to C5a generation during venous thrombosis in mice.

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Plasmin, a protease generated in response to thrombin generation and fibrin deposition, efficiently cleaves C5 to C5a.

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In an arterial thrombosis model, administration of a plasminogen activator augments C5a plasma levels.

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Plasmin participates in immunothrombosis, liberating chemotactic C5a and inducing assembly of the procoagulant C5b-9.

Venous and arterial thrombosis are major causes of death and morbidity. Leukocytes are early and active participants in thrombus formation, recruited partly by complement factor C5a. We examined how C5a is generated in the setting of thrombosis. In venous thrombosis in mice, we show that thrombin, a key clot-promoting enzyme, is not a major contributor to C5a generation. Rather, plasmin, a fibrinolytic enzyme formed in response to thrombin generation and clot formation, efficiently generates C5a. The findings were validated in an arterial thrombosis model in mice. These insights may be valuable in developing therapeutic strategies to limit thrombus formation.

A treatment option for severe cerebellar hemorrhage with ventricular extension in elderly patients: intraventricular fibrinolysis

External ventricular drainage (EVD) combined with intraventricular fibrinolysis (IVF) is rarely used in severe spontaneous cerebellar hemorrhage (SCH) with intraventricular hemorrhage (IVH). Recently, the treatment strategy was repeatedly performed in our hospital to elderly patients with severe SCH + IVH. To analyze its clinical value, we compared it to two treatment strategies which now commonly are used for these patients: conservative management (CM) and clot evacuation (CE). In this study, a total of 118 cases were observed, of which 28 cases received CM, 43 cases received EVD + IVF and 47 cases received CE. The Glasgow Coma Scale score, frequency of complication, mortality in one month, modified Rankin Scale (mRS) at six months, and causes of death were analyzed. The outcomes of patients in the CM group were extremely poor compared to patients undergoing surgery (P = 0.034) and the mortality was up to 61.3 % (18/28), which was much higher than those of the two surgical groups (P = 0.026). No significant difference was found in mortality and mRS between the two surgical groups (P > 0.05). Patients in the CE group mostly died of deterioration of comorbidities and postoperative complications, whereas more deaths occurred in the CM group and the EVD + IVF group due to rebleeding, brainstem compression, perilesional edema and tight posterior fossa (χ (2), P = 0.006). It is suggested that EVD + IVF is a treatment option for elderly patients with severe SCH + IVH.

Meta-analysis of clinical outcomes of intravenous recombinant tissue plasminogen activator for acute ischemic stroke: within 3 hours versus 3-4.5 hours

OBJECTIVE

This meta-analysis was to compare clinical outcomes of intravenous recombinant tissue plasminogen activator (IV rtPA) administered within 3 hours versus 3-4.5 hours after symptom onset.

METHODS

We collected all interventional or observational studies that compared clinical outcomes of IV rtPA treatment within 3 hours and 3-4.5 hours after acute ischemic stroke onset by searching PubMed (up to October 2012), Embase (1966 to October 2012) and Web of Science (2003 to October 2012) as well as manually searching the references of articles retrieved. The combined effect was calculated by odds ratios (ORs) and 95% confidence intervals (CIs) to analyze favorable functional outcome, mortality and symptomatic intracranial hemorrhage (sICH) at 90 days. Publication bias was analyzed by Begg's funnel plot and Egger's regression test.

RESULTS

Our initial search identified a total of 27,391 articles. After reviewing the titles, abstracts and full text, a total of six studies and more than 25,000 patients were included in the final meta-analysis. The combined analyses demonstrated significant differences in the favorable outcome (modified Rankin scale, mRS: 0-2): OR = 0.89, 95% CI = 0.81-0.98 and very favorable outcomes (mRS: 0-1): OR = 0.86, 95% CI = 0.78-0.94 between two groups, which were both in favor of the 3-4.5 hours group. When all studies reporting data on sICH were combined, the overall summary OR indicated no differences in the two groups. The combined analyses showed no significant differences in 90 day mortality and 7 day mortality between within 3 hours and 3-4.5 hours.

CONCLUSIONS

This meta-analysis does not provide any evidence that treatment with rtPA within 3-4.5 hours is less safe than treatment within 3 hours. It suggests that treatment with IV rtPA may be recommended to ischemic stroke patients that present within 4.5 hours of onset, although every effort should be made to give those patients IV rtPA within 3 hours of symptom onset.

CT angiography in an acute stroke protocol: correlation between occlusion site and outcome of intravenous thrombolysis

Thrombolysis with intravenous rt-PA is the current therapy for acute ischemic stroke. Unlike other outcome factors, relatively little is known about the prognostic value of the occlusion site on treatment outcome. We compared the effectiveness and safety of intravenous thrombolysis in patients with different levels of occlusion identified by CT angiography (CTA) in anterior circulation stroke, and analyzed the influence of the occlusion site on treatment outcome in relation to other outcome factors. We selected 71 patients from a stroke database collected between June 2007 and December 2011 at our hospital. All of the studied patients had anterior circulation stroke with intracranial occlusion detected by CTA and were treated with intravenous rt-PA. They were divided into two groups according to the site of occlusion along the middle cerebral artery course: proximal (carotid "T", complete M1 and mild M1 occlusions) and distal (M2/M3 occlusions). Treatment effectiveness was assessed by modified Rankin Scale (mRS) at three months, considering a positive outcome a mRS value ≤ 2. Treatment safety was assessed by evaluating the rate of hemorrhagic complications seen on unenhanced CT at 24 hours. Binary logistic regression was performed to evaluate the interaction between occlusion site and other variables such as sex, age, ASPECT score on admission and baseline NIHSS value in determining treatment outcome. The degree of effectiveness and safety differed when considering patients with proximal and distal occlusions. The percentage of successfully treated cases was 28.6% in the first group compared to 72% in the second, and the rate of hemorrhagic complications was 28.6% and 6% respectively. After adjustment for sex, age, ASPECT score on admission and baseline NIHSS value, occlusion site was the only variable significantly influencing treatment safety and, together with baseline NIHSS value, the only valid predictor of treatment effectiveness. We demonstrated a correlation between the site of arterial occlusion and outcome of intravenous thrombolysis. By helping the choice of the best therapeutic strategy depending on the identified occlusion site, CTA could be usefully added to the examinations included in the Stroke Protocol for the baseline evaluation of patients with suspected acute stroke.

Lessons learned from 2 years experience in intravenous thrombolysis for acute ischemic stroke in a single tertiary medical center

BACKGROUND

Intravenous tissue plasminogen activator has been approved treatment for acute (< or = 3 hours) ischemic stroke in Israel since late 2004. The Israeli experience with IV tPA is still limited. Several factors may influence the response to IV thrombolysis, including time-to-treatment parameters and tandem internal carotid artery/middle cerebral artery stenosis/occlusion.

OBJECTIVES

To compare our experience with IV tPA treatment of patients with acute ischemic stroke to the findings of the SITS-MOST (Safe Implementation of Thrombolysis in Stroke-MOnitoring STudy, international data) and of the Sheba Medical Center (national data) and to compare the early outcome among patients with ischemic stroke in the MCA with and without severe ICA stenosis.

METHODS

We obtained demographic data, timing details, stroke severity, hemorrhagic complications, mortality, and early outcome from the records of IV tPA-treated acute ischemic stroke patients.

RESULTS

Fifty-eight patients (median age 69 years, 26 females) with acute ischemic stroke were treated by IV tPA at the Tel Aviv Sourasky Medical Center in 2006-2007. Median time between stroke onset and IV tPA administration was 148 minutes for the Sourasky center, 150 minutes for the Sheba center, and 140 minutes for SITS-MOST. The Sourasky mortality rate was 10.5%. Of the 31 patients who suffered MCA stroke, 8 had severe ipsilateral ICA stenosis. These 8 had significantly lower neurological improvement than the 23 without ipsilateral ICA stenosis (1/8 versus 15/23, P < 0.001).

CONCLUSIONS

Our data demonstrate fairly similar parameters of IV tPA treatment compared to other centers and suggest that patients with severe ICA stenosis might be less likely to benefit from IV tPA.

Clinical improvement in systemic sclerosis resulting from urokinase therapy explained by light and electron microscopy skin examination

OBJECTIVE

In our previous work, patients affected by SSc were treated with intravenous urokinase and showed clinical improvement. In this study we used microscopy to document ultrastructural alterations occurring in sclerodermic skin from SSc patients treated with urokinase.

METHODS

Ten patients with SSc were selected for this study. Skin biopsies were taken from the medial side of the right forearm on the third proximal on the volar surface. The patients were then treated with urokinase for 7 consecutive days. At the end of the treatment, the patients were examined and a new skin biopsy was taken close to the above-mentioned zone of the forearm for optic and electron microscopy examination.

RESULTS

The patients showed a gradual improvement of the skin after urokinase treatment. Raynaud's appeared to be less intense, and they had an increased articular range, with the restoration of movements that had previously been limited. Histological findings showed that, after treatment, skin alterations appeared attenuated, in particular the connective tissue showed a decreased density and inflammatory infiltrate was slight. Electron microscopy findings showed that collagen fibres appeared to have a more regular diameter, and the capillary vessels' lining was thicker, with fewer pinocytotic vesicles.

CONCLUSION

These observations show that urokinase treatment seems to be an interesting therapeutic strategy to consider for the treatment of SSc.

Resolution of ST-segment elevation after streptokinase therapy in anterior versus inferior wall myocardial infarction

BACKGROUND

Resolution of ST-segment elevation is the best bedside predictor of myocardial reperfusion.

HYPOTHESIS

This study was conducted to examine the resolution of ST-segment elevation after streptokinase therapy in anterior versus inferior acute myocardial infarction (MI) and to corroborate it with echocardiographic and coronary angiographic data.

METHODS

The study population consisted of 70 patients, 35 each in the anterior and inferior MI groups. The electrocardiograms (ECGs) were recorded before, on completion of, and on Days 1 and 2 post streptokinase therapy. The resolution of ST segment determined from post-streptokinase ECGs was compared between the two groups and correlated with echocardiographic and coronary angiographic data.

RESULTS

On completion of and on Day 1 post streptokinase therapy, ST-segment resolution in both groups was not significantly different. On Day 2 post streptokinase therapy, resolution of the ST segment per lead was significantly lower in anterior than that in inferior MI (61 +/- 21% anterior vs. 77 +/- 21% inferior, p 0.003). The number of patients with akinesis of infarct-related ventricular wall was significantly higher (17 anterior vs. 7 inferior, p 0.02), and left ventricular ejection fraction was significantly lower in anterior MI (39 +/- 7% anterior vs. 48 +/- 8% inferior, p < 0.01). There was no significant difference in coronary angiographic data. One patient in each group demonstrated normal coronary arteries.

CONCLUSIONS

The resolution of ST-segment elevation on the completion of and on Day 1 post streptokinase therapy was comparable between anterior and inferior MI. The significantly less frequent resolution of ST-segment elevation in anterior MI on Day 2 post streptokinase could be due to more akinesis, larger infarct size, and worse systolic function rather than due to failure to open the infarct-related vessel.

Prognostic role of plasminogen-activator-inhibitor-1 levels in treatment with streptokinase of patients with acute myocardial infarction

BACKGROUND

The antifibrinolytic effect of plasminogen-activator-inhibitor type 1 (PAI-1) may be responsible for delays in reperfusion and/or reinfarctions after streptokinase (STK) therapy in patients with acute myocardial infarction (AMI).

HYPOTHESIS

This study aimed to demonstrate the prognostic role of pretreatment PAI-1 levels for the outcome of STK therapy in patients with AMI, depending on reperfusion and/ or reinfarction.

METHODS

The mean pretreatment PAI-1 level of 104 patients with AMI, treated with STK, determined by chromogenic method, was 5.8 +/- 8.6 U/ml, range 0.3-66.2 U/ml. Streptokinase therapy was successful when reperfusion was achieved, as assessed noninvasively, without subsequent reinfarction; it failed when reperfusion was delayed and/or reinfarction developed.

RESULTS

Fibrinolysis with STK failed significantly in patients with elevated pretreatment PAI-1 levels (p < 0.05), especially with levels >4.0 U/ml (p< 0.01). The mean pretreatment PAI-1 level was significantly higher in unsuccessfully treated patients. Multivariate statistical testing demonstrated that among pretreatment variables, elevated PAI-1 activity was the most significant independent risk factor of failed fibrinolysis with STK.

CONCLUSIONS

Among pretreatment variables, elevated pretreatment PAI-1 activity in patients with AMI was the most significant independent risk factor of failed fibrinolysis with STK, especially at levels > 4.0 U/ml.

Intrapulmonary artery infusion of urokinase for treatment of massive pulmonary embolism: a review of 26 patients with and without contraindications to systemic thrombolytic therapy

BACKGROUND

Pulmonary emboli (PE) are a common event seen in over 600,000 patients a year. Occurring suddenly, PE often result in a high rate of mortality. To combat the high rate of mortality, more aggressive therapies including the use of thrombolytics are often indicated. The use of intrapulmonary artery infusion of urokinase has been shown to promote rapid resolution of emboli and restoration of normal pulmonary hemodynamics.

HYPOTHESIS

The study was undertaken to review the effectiveness and safety of pulmonary artery infusion of urokinase in 26 patients with and without contraindications to the use of systemic thrombolytic therapy.

METHODS

We reviewed the outcomes of 26 patients who received infusion of urokinase, using a usual loading dose of 4,000 U/kg body weight given as a bolus, followed by 4,000 U/kg/h for 12 to 24 h, using either/or unilateral or bilateral infusions. Pulmonary angiograms were obtained prior to and following the urokinase infusions.

RESULTS

Intrapulmonary artery infusion of urokinase was given to 26 patients, 9 of whom had contraindications to the use of systemic thrombolytic therapy. Six patients were recent post operative, one was receiving oral anticoagulants, one was receiving chemotherapy with bleeding complications, and one had received cardiopulmonary resuscitation. Twenty of the patients returned to their baseline state (normal heart rate, blood pressure, and p02), one was minimally improved, and five deaths occurred. Of the five deaths, three occurred within 1 h of starting urokinase infusion, the remaining two died more than 36 h after treatment with urokinase as a result of their basic underlying disease. Minor bleeding occurred from puncture sites, two hematomas occurred at the puncture site, and there were two gastrointestinal bleeds, one of which occurred a week post urokinase therapy while the patient was receiving heparin and coumadin. No central nervous system bleeds occurred and no transfusions were required as a result of urokinase intrapulmonary artery infusions. The overall mortality rate in this series was 11.5%.

CONCLUSIONS

Intrapulmonary artery infusion of urokinase in extensive pulmonary embolism is a safe and efficient treatment in patients with and without contraindication to the use of systemic thrombolytic therapy. With a usual loading dose of 4,000 U/kg body weight, followed by an infusion of 4,000 U/kg/h for 12 to 24 h, it produces significant and rapid resolution of pulmonary emboli with a low morbidity and mortality rate. In our series, the mortality rate was 11.5%, and none of the deaths was the direct result of urokinase therapy.

[Intravenous administration of a tissue plasminogen activator beyond 3 hours of the onset of acute ischemic stroke--MRI-based decision making]

After large CT-based clinical trials have failed to prove the benefits of intravenous tissue plasminogen activator (tPA) administration for ischemic stroke patients beyond 3 hours of the onset of the concept of PWI/DWI mismatch which is the volume difference between a PWI lesion and DWI lesion on MRI scans, has been proposed to facilitate the selection of patients with a salvageable area. PWI/DWI mismatch is considered to represent the tissue that is not irreversibly injured and can respond to early reperfusion therapy. When an ischemic lesion is divided into 4 regions, namely, ischemic core, reversible DWI lesion, penumbra and benign oligemia, both the reversible DWI lesion and penumbra are considered to be an optimal targets for thrombolysis. In order to clarify the clinical significance of PWI/DWI mismatch in the selection of candidates for tPA therapy, some multicenter trials were performed. The results of DIAS (desmoteplase in acute ischemic stroke)/DEDAS (dose escalation of desmoteplase for acute ischemic stroke)/DIAS-2 did not difinitly demonstrate the clinical benefits of desmoteplase administration in patients with PWI/DWI mismatch between 3 to 9 hours of onset; in fact, DIAS-2 could not prove any effect of the drug. DEFUSE (diffusion and perfusion imaging evaluation for understanding stroke evolution), in which tPA was administered to all participants between 3 to 6 hours of stroke onset, showed that the occurrence of early reperfusion led to a favorable clinical response in patients with PWI/DWI mismatch. In contrast, early reperfusion was not beneficial in patients without PWI/DWI mismatch. In EPITHET (echoplanar imaging thrombolysis evaluation trial), stroke patients who showed PWI/DWI mismatch after 3 to 6 hours of the onset were assigned to receive either alteplase or placebo administration: lesion growth was lesser in patients with alteplase than in those who received placebo, although the difference was not statistically significant because of a small number of participants. Although these results supported the importance of the PWI/DWI concept, there still remain some issues to be resolved. Regarding the definition of PWI/ DWI mismatch, a larger mismatch ratio than the one that has been typically used seems to be recommended. Most useful parameters of PWI should be determined to standardize volume evaluation using MRI scans. For the institutes where MRI scans are not available 24 hours a day, clinical DWI mismatch has been proposed as an alternative to of PWI/DWI mismatch. The application of MRI-based decision making strategy for stroke patients may facilitate the assessment and treatment of stroke patients beyond 3 hours of stroke onset, and is expected to allow the use of tPA for a substantially greater number of patients.

Effektive Schlaganfalltherapie jenseits der Zulassungsbeschränkungen: intravenöse Thrombolyse im erweiterten Zeitfenster (> 3 h) und bei alten Patienten (≥ 80 J.)

Intravenous thrombolysis with tPA is the only approved and effective treatment for acute ischemic stroke. The approval, however, is restricted to treatment within 3 hours of stroke onset, and it is not recommended to treat patients beyond 80 years of age. Due to these restrictions, thrombolysis is only given to a small number of acute stroke patients. At the same time there is growing evidence that patients can be treated with thrombolysis safely and effectively even beyond these restrictions. We give an overview over the published data regarding thrombolysis beyond the 3 hour time window and in patients aged 80 or over. Based on these data we conclude that (1.) intravenous thrombolysis in MRI selected patients is safe and effective within an extended time window of up to 6 hours, and (2.) there is no increase in mortality or symptomatic intracerebral bleeding complications in patients aged 80 or over treated with thrombolysis. A great number of acute stroke patients reaches the hospital beyond the 3 hour time window, and there is a growing number of old and very old stroke patients in the western world. Treating patients up to a 6 hour time window and beyond the age of 80 years would clearly increase the number of patients, which might benefit from this effective treatment. To summarize, we recommend experienced stroke centres to treat acute stroke patients with thrombolysis up to 6 hours using MRI criteria for patient selection, and to treat also patients aged 80 years or older.

Staphylococcus aureus exploits cathelicidin antimicrobial peptides produced during early pneumonia to promote staphylokinase-dependent fibrinolysis

The increasing prevalence of Staphylococcus aureus strains isolated from hospital- and community-acquired respiratory tract infections is an important public health concern worldwide. The majority of S. aureus strains produce staphylokinase, a plasminogen activator capable of inactivating neutrophil alpha-defensins and of impairing phagocytosis via opsonin degradation. Cathelicidin antimicrobial peptides are present at sites of infection before the release of neutrophil alpha-defensins. Therefore, we hypothesized that staphylokinase interacts with cathelicidin during the early pathogenesis of S. aureus airway infection. In a mouse intranasal infection model, cathelicidin was strongly up-regulated in the airways during the development of staphylococcal pneumonia. In vitro, cathelicidin bound directly to staphylokinase and augmented staphylokinase-dependent plasminogen activation and fibrinolysis at concentrations consistent with those detected in the airways during infection. These data suggest that staphylokinase production may be a novel virulence mechanism by which S. aureus exploits cathelicidin to promote fibrinolysis, leading to enhanced bacterial dissemination and invasive infection.

Design and characterization of a platelet-targeted plasminogen activator with enhanced thrombolytic and antithrombotic potency

To obtain a thrombus-targeted plasminogen activator with high affinity for activated platelets and enhanced thrombolytic and antithrombotic potency, we engineered a sequence encoding RGDS (Arg-Gly-Asp-Ser) peptide into the loop between domains II and III of the sequence-deleted mutant of annexin B1 and then constructed a chimaeric plasminogen activator gene mAnxB1-RGDS-ScuPA by fusing ScuPA32k [low-molecular-mass single-chain urokinase (32 kDa)] with the N-terminus. The chimaeric protein was expressed in inclusion bodies in Escherichia coli at 25% of the total cellular protein content. Ion-exchange and gel-filtration chromatographies were applied to purify the chimaeric protein, achieving purity greater than 98%. We demonstrated that this chimaera can be expressed and purified in an active form; in vitro testing indicated that the chimaera fully retained the thrombolytic activity, platelet membrane-binding activity and anti-platelet aggregation activity of the parent molecules. The plasma clearance of the chimaera was similar to that of urokinase and ScuPA32k. In vivo experiments in a canine system indicated that animals administered the chimaera presented a decreased time to reperfusion, higher reperfusion ratio and less bleeding effects than treatment with urokinase. These results show that the chimaera is a platelet-targeted plasminogen activator with enhanced thrombolytic and antithrombotic potency that may have advantages over currently available thrombolytic agents.

Therapy for early reperfusion after stroke

Ischemic stroke is a leading cause of death and disability in the Western world. At present, intravenous administration of tissue plasminogen activator within 3 h of symptom onset is the only proven effective treatment to re-establish cerebral blood flow in the case of acute vessel occlusion. Unfortunately, few patients presenting with acute ischemic stroke qualify for intravenous tissue plasminogen activator therapy. The focus of current research is, therefore, to find new treatment options by which to obtain early reperfusion, and to extend the therapeutic window for intervention beyond 3 h. The purpose of this Review is to provide an integrated view of the current state of reperfusion therapy in patients with acute stroke, including pharmacologic agents and the methods of delivery. The focus will be on intravenous and intra-arterial use of plasminogen activators in acute supratentorial infarction. Other therapies, such as antiplatelet agents (i.e. glycoprotein IIb/IIIa inhibitors), and anticoagulant drugs will be discussed briefly.

Prospective Studies in Patients with Intraventricular Haemorrhage Without the Capacity to Give Consent in Germany - A Legal Dilemma

OBJECTIVE

The prognosis of intracranial haemorrhage with ventricular participation is poor. The acute onset of hydrocephalus has to be treated with an external ventricular drainage. However, intraventricular blood clots often obstruct the drainage catheter; the reinsertion is usually associated with an increased risk of complications. Therefore, intraventricular thrombolysis using recombinant tissue plasminogen activator (rt-PA), urokinase or streptokinase has been performed in several cases. In Germany, rt-PA does not have approval for intraventricular applications, and the risks and benefits of this treatment are as yet unclear. Several authors recommend its use only in the frame of prospective studies, meaning that intraventricular administration of thrombolytic agents within an individual therapy trial could be viewed as medical malpractice.

METHODS

We designed a national prospective randomised and controlled study in patients with intraventricular haemorrhage to investigate the risks and effects of intraventricular rt-PA treatment. The local ethics committee and lawyers did not accept the study protocol due to a non-acceptable risk of complications. In two further conferences, the risk of undertreatment in the control group was a major reason not to accept the protocol. We discuss the conflicts of law in related studies.

CONCLUSIONS

There is a need for a solution to the legal conflicts of medical malpractice, unclear risk-benefit ratio and unfeasibility due to risk of complications or undertreatment in studies with patients without the capacity to give informed consent.

Angiostatin generating capacity and anti-tumour effects of D-penicillamine and plasminogen activators

Background

Upregulation of endogenous angiostatin levels may constitute a novel anti-angiogenic, and therefore anti-tumor therapy. In vitro, angiostatin generation is a two-step process, starting with the conversion of plasminogen to plasmin by plasminogen activators (PAs). Next, plasmin excises angiostatin from other plasmin molecules, a process requiring a donor of a free sulfhydryl group. In previous studies, it has been demonstrated that administration of PA in combination with the free sulfhydryl donor (FSD) agents captopril or N-acetyl cysteine, resulted in angiostatin generation, and anti-angiogenic and anti-tumour activity in murine models.

Methods

In this study we have investigated the angiostatin generating capacities of several FSDs. D-penicillamine proved to be most efficient in supporting the conversion of plasminogen to angiostatin in vitro. Next, from the optimal concentrations of tPA and D-penicillamine in vitro, equivalent dosages were administered to healthy Balb/c mice to explore upregulation of circulating angiostatin levels. Finally, anti-tumor effects of treatment with tPA and D-penicillamine were determined in a human melanoma xenograft model.

Results

Surprisingly, we found that despite the superior angiostatin generating capacity of D-penicillamine in vitro, both in vivo angiostatin generation and anti-tumour effects of tPA/D-penicillamine treatment were impaired compared to our previous studies with tPA and captopril.

Conclusion

Our results indicate that selecting the most appropriate free sulfhydryl donor for anti-angiogenic therapy in a (pre)clinical setting should be performed by in vivo rather than by in vitro studies. We conclude that D-penicillamine is not suitable for this type of therapy.

IV tissue plasminogen activator use in acute stroke: experience from a statewide registry

OBJECTIVE

To assess the use of IV recombinant tissue plasminogen activator (rt-PA) in a statewide hospital-based stroke registry and to identify factors associated with its use among eligible patients.

METHODS

A modified stratified sampling scheme was used to obtain a representative sample of 16 hospitals. Prospective case ascertainment and data collection were used to identify all acute stroke admissions over a 6-month period. Subjects eligible for IV rt-PA were defined as those who arrived within 3 hours of onset, who had no evidence of hemorrhage on initial brain image, and who had no physician-documented reasons for non-treatment with IV rt-PA. Multivariate logistic regression was used to identify factors associated with IV rt-PA use.

RESULTS

Of 2,566 stroke admissions, 330 (12.9%) met the eligibility criteria for rt-PA treatment, and of these 43 (13%) received IV rt-PA treatment. Among 2,236 admissions excluded from consideration, 21% had evidence of hemorrhage on initial imaging, 35% had unknown stroke onset times, 38% had an onset to arrival time >3 hours, and 6% had physician documented contraindications. Among eligible patients, being male, use of emergency medical services, and rapid presentation were associated with increased IV rt-PA use.

CONCLUSIONS

Treatment with IV rt-PA was underutilized in this hospital-based stroke registry. The primary reason for nontreatment was delayed presentation. Reducing prehospital and in-hospital response times would help increase IV rt-PA use, as would greater emergency medical services use. Improving the documentation of onset times would help clarify the underlying causes of delayed presentation.

Dose Escalation of Desmoteplase for Acute Ischemic Stroke (DEDAS)

Background and Purpose— Desmoteplase is a novel plasminogen activator with favorable features in vitro compared with available agents. This study evaluated safety and efficacy of intravenous (IV) desmoteplase in patients with perfusion/diffusion mismatch on MRI 3 to 9 hours after onset of acute ischemic stroke.

Methods— DEDAS was a placebo-controlled, double-blind, randomized, dose-escalation study investigating doses of 90 μg/kg and 125 μg/kg desmoteplase. Eligibility criteria included baseline National Institute of Health Stroke Scale (NIHSS) scores of 4 to 20 and MRI evidence of perfusion/diffusion mismatch. The safety end point was the rate of symptomatic intracranial hemorrhage. Primary efficacy co-end points were MRI reperfusion 4 to 8 hours after treatment and good clinical outcome at 90 days. The primary analyses were intent-to-treat. Before unblinding, a target population, excluding patients violating specific MRI criteria, was defined.

Results— Thirty-seven patients were randomized and received treatment (intent-to-treat; placebo: n=8; 90 μg/kg: n=14; 125 μg/kg: n=15). No symptomatic intracranial hemorrhage occurred. Reperfusion was achieved in 37.5% (95% CI [8.5; 75.5]) of placebo patients, 18.2% (2.3; 51.8) of patients treated with 90 μg/kg desmoteplase, and 53.3% (26.6; 78.7) of patients treated with 125 μg/kg desmoteplase. Good clinical outcome at 90 days occurred in 25.0% (3.2; 65.1) treated with placebo, 28.6% (8.4; 58.1) treated with 90 μg/kg desmoteplase and 60.0% (32.3; 83.7) treated with 125 μg/kg desmoteplase. In the target population (n=25), the difference compared with placebo increased and was statistically significant for good clinical outcome with 125 μg/kg desmoteplase ( P =0.022).

Conclusions— Treatment with IV desmoteplase 3 to 9 hours after ischemic stroke onset appears safe. At a dose of 125 μg/kg desmoteplase appeared to improve clinical outcome, especially in patients fulfilling all MRI criteria. The results of DEDAS generally support the results of its predecessor study, Desmoteplase in Acute Ischemic Stroke (DIAS).

Fibrinolytic treatment for acute ischaemic stroke

Ischaemic stroke is a leading cause of death and disability in the US. At present, intravenous administration of tissue plasminogen activator within 3 h of symptom onset is the only proven effective treatment for patients with acute ischaemic stroke. Unfortunately, most treated patients do not make a functional recovery and very few patients presenting with acute stroke qualify for intravenous tissue plasminogen activator therapy. The focus of current research is to extend the therapeutic window for intervention beyond 3 h, and to improve the outcome of treated patients. The purpose of the present paper is to describe the current state of affairs for intravenous plasminogen activators, and to review recently published research. Agents and strategies under investigation include the intra-arterial delivery of plasminogen activators or antiplatelet agents, as well as combined intravenous/intra-arterial protocols.

Plasminogen activators: A comparison

Thrombolytic drugs play a crucial role in the management of patients with acute myocardial infarction, pulmonary embolism, deep vein thrombosis, arterial thrombosis, acute thrombosis of retinal vessel, extensive coronary emboli, and peripheral vascular thromboembolism. Recognition of the importance of fibrinolytic system in thrombus resolution has resulted in the development of different fibrinolytic agents. Now a days several newer plasminogen activators with different pharmacokinetic and pharmacodynamic properties have been developed to treat thrombotic disease, which are fibrin specific with prolonged half-life and can be administered as a single bolus.

Intravenous Thrombolysis for Acute Ischaemic Stroke: Preliminary Experience with Recombinant Tissue Plasminogen Activator in the UK

OBJECTIVE

To present the preliminary experience of implementing intravenous thrombolytic therapy for acute ischaemic stroke in three UK stroke centres.

BACKGROUND

Recombinant tissue plasminogen activator for ischaemic stroke received approval from UK regulatory authorities in April 2003. Since 1997, a small number of UK centres had used thrombolytic therapy in highly selected stroke patients. We present the early experience of that treatment in Glasgow and Newcastle.

DESIGN

Patients were selected and treated in accordance with the American Heart Association guidelines. Additionally, radiologic criteria employed in the European-Australasian Acute Stroke Studies were applied. National Institutes of Health Stroke Scale (NIHSS) scores were measured on admission, and Modified Rankin Scale (MRS) scores were assessed at 3 months for all patients with stroke treated prior to initiation of the Safe Implementation of Thrombolysis in Stroke monitoring program for implementation of thrombolysis in stroke in April 2001. Intracranial and systemic haemorrhagic complications were recorded.

RESULTS

120 patients received thrombolytic treatment (approximately 1% of all admissions with presumed stroke). Mean age was 69 years (range 22-93) and initial median NIHSS score was 17 (range 3-31). In the two centres for which temporal data were available, the mean delay between symptom onset and treatment was 139 min (range 20-185). Sixteen episodes of cerebral haemorrhage or haemorrhagic transformation of any degree occurred, of which 5 (4%) were symptomatic. One patient deteriorated and died before repeat CT imaging could be performed. One non-fatal episode of systemic bleeding occurred. One patient was lost to follow-up. At 3 months, 31% of recipients had achieved good (MRS 0-1) outcome, 22% moderate (MRS 2-3) outcome and 21% (MRS 4-5) poor outcome. Twenty-one per cent died within 3 months of stroke. Observed frequency of bleeding complications and protocol violations (6%) was similar to those reported elsewhere.

CONCLUSION

A small proportion of stroke patients received thrombolytic treatment. Patients treated were more severely affected than in other published European and North American series. Outcomes and complications were consistent with experience elsewhere.

In vivo generation of angiostatin isoforms by administration of a plasminogen activator and a free sulfhydryl donor: a phase I study of an angiostatic cocktail of tissue plasminogen activator and mesna

PURPOSE

Angiostatin4.5 (AS4.5), the endogenous human angiostatin, is derived from plasminogen in a two-step process. A plasminogen activator converts plasminogen to plasmin, then plasmin undergoes autoproteolysis to AS4.5. A free sulfhydryl donor can mediate plasmin autoproteolysis. To translate this process to human cancer therapy, we conducted a phase I trial of administration of a tissue plasminogen activator (tPA) with a free sulfhydryl donor (mesna).

PATIENTS AND METHODS

Fifteen patients with advanced solid tumors were treated. The dose of tPA was escalated (cohorts; 1, 2, 3, 5, and 7.5 mg/h for 6 hours). Mesna was administered as a 240 mg/m2 bolus followed by an infusion of 50 mg/h, concurrent with tPA. Both tPA and mesna were administered 3 consecutive days every 14 days.

RESULTS

No dose-limiting toxicity was observed. Two AS4.5 isoforms were generated, Lys-AS4.5 and Glu-AS4.5. Mean baseline Lys-AS4.5 level was 20.4 nmol/L (SE, 2.9). In the 5 mg/h tPA cohort, Lys-AS4.5 levels increased by an average of 143% or 24 nmol/L (SE, 4.9) above baseline. Glu-AS4.5 (M(r) approximately 62,000) was also generated (additional 77 amino acids at amino terminus compared with Lys-AS4.5). Glu-AS4.5 level at baseline was undetectable in four of five patients in the 5 mg/h tPA cohort, but at end of infusion, was approximately 67 nmol/L (SE, 20). Two patients in the 5 mg/h tPA cohort experienced decreases in tumor markers with treatment, although no clinical objective responses were observed.

CONCLUSION

This study shows that in vivo generation of AS4.5 is safe in humans and may provide a practical approach to achieve antiangiogenic therapy.

Intravenous TPA for very old stroke patients

BACKGROUND

Although thrombolysis in patients with advanced age is considered more risky, some may benefit from TPA treatment. We studied safety and recanalization/recovery in patients older than 80 years treated with TPA and compared them with younger stroke patients.

METHODS

We studied patients treated with intravenous TPA and divided them into younger (<80 years) and older (> or =80 years) groups for comparison. Diagnostic transcranial Doppler was completed before bolus, and patients were consequently monitored for up to 2 h when feasible. Clinical data included NIH Stroke Scale score, symptomatic intracranial hemorrhage (ICH) and discharge disposition.

RESULTS

We studied 127 younger (mean 63 years, range 31-79) and 56 older patients (mean 84 years, range 80-93). Median baseline NIH Stroke Scale score was higher in the older group (18 vs. 14 points, NS). Occlusion locations, onset to needle time (median 130 vs. 120 min) as well as improvement at 24 h (median 5 vs. 4 points) were similar in both groups. Transcranial Doppler monitoring showed similar partial or complete recanalization rates (66 vs. 66%), onset to recanalization time (median 160 vs. 158 min) and reocclusion rates (26 vs. 25%). Symptomatic and fatal ICH was not higher in the older group (7.1 and 3.5% vs. 6.3 and 3.9%, NS). There was higher mortality among older patients (20 vs. 11%, NS). At discharge, 23% of older patients went home, 41% underwent rehabilitation and 16% were transferred to skilled nursing facilities, compared with 31, 43 and 15% respectively, in the younger group.

CONCLUSION

After intravenous TPA treatment, patients over 80 years of age have similar recanalization, short-term improvement and symptomatic ICH rates compared with younger patients. However, older patients tend to have higher in-hospital mortality.

Role of MC-1 alone and in combination with tissue plasminogen activator in focal ischemic brain injury in rats

OBJECT

Pyridoxal-5-phosphate (PLP), the biologically active form of pyridoxine, can rescue neurons from death in vitro and in vivo. In the present project, the authors have studied whether MC-1, an analog of PLP, alone or in combination with the thrombolytic agent tissue plasminogen activator (tPA), can protect the brains of rats injured by ischemia.

METHODS

Ischemic brain injury was induced in rats by injecting a preformed blood clot in the middle cerebral artery (MCA). Neurological deficits and infarct volumes caused by the embolus were measured to evaluate the effects of MC-1 on the ischemic injury. Systemic blood pressure and local brain blood flow were also monitored. Administration of different doses of MC-1 1 hour after embolization significantly reduced the infarct volume and improved functional recovery. Injection of MC-1 (40 mg/kg) at 3 or 6 hours after embolization also reduced the volume of the infarct significantly and improved functional recovery. Combined treatment with MC-1 and tPA was also neuroprotective, although it was not superior to treatment involving either MC-1 or tPA alone. Treatment with MC-1 did not result in significant changes in either systemic blood pressure or local blood flow in the ischemic brain.

CONCLUSIONS

These data support the hypothesis that in the focal embolic stroke model in rats MC-1 is a neuroprotective agent. The neuroprotection this compound provides still exists when MC-1 administration is delayed up to 6 hours after ischemic injury.

Acute thromboembolic events during carotid artery angioplasty and stenting: etiology and a technique of neurorescue

PURPOSE

To review the protected carotid stenting experience at two major referral centers to evaluate the frequency of clinically significant intraprocedural thromboembolic events, use of neurorescue techniques, and ultimate clinical outcomes.

METHODS

A retrospective review was conducted of 254 cases of protected transfemoral carotid stenting performed at the Washington University-Barnes Hospital and The Fleni Institute of Buenos Aires in a 6-year period. Medical records of patients with periprocedural thromboembolic events were reviewed to determine the type of complication, method of treatment, and outcome.

RESULTS

Among the 254 cases in which a carotid protection device was used, 2 (0.79%) episodes of witnessed, symptomatic thromboembolism occurred. Both patients suffered thromboembolic occlusion of the M1 branch of the middle cerebral artery (MCA) immediately following crossing of the internal carotid lesion with the protection device. Neurological symptoms consisted of agitation, aphasia, and hemiplegia in both patients. After rapid stent deployment across the carotid lesion, the MCA was cannulated and the occlusion treated with balloon angioplasty. This was followed by selective intra-arterial delivery of urokinase and intravenous abciximab. These maneuvers resulted in excellent restoration of blood flow in the MCA and its branches. With the exception of minor word-finding difficulties in one, both patients demonstrated full neurological recovery within the perioperative period.

CONCLUSIONS

In our experience, intraprocedural thromboembolic events occur despite the use of cerebral protection devices, but are rare. Notably these complications appeared to occur at the time of lesion crossing by distal cerebral protection devices. These thromboembolic events can be successfully treated if the complication is rapidly identified and the physician is adequately prepared and proficient in neurorescue techniques.

Thrombolytic therapy followed by stenting for renal artery dissection secondary to blunt trauma

A 18-year-old man presented at our clinic with pain in the right flank following a motorbike accident. The diagnosis of renal artery dissection followed by thrombosis was made by computed tomography and confirmed by angiography. Successful revascularization was performed by means of repeated transcatheter injection of small doses of thrombolytic agents within the vessel, followed by deployment of a self-expandable stent. There were no complications, and the patient recovered well. Six months after stent placement, a selective renal angiogram showed excellent flow through the stented portion of the artery and normal parenchyma enhancement in the right kidney.

IV tPA for Acute Ischemic Stroke

BACKGROUND

Reviews of the use of intravenous tissue type plasminogen activator (IV tPA) for acute stroke in community hospitals have raised questions regarding its safe use in community practice settings outside major academic stroke centers. Many neurologists have been reluctant to use IV tPA in their practices. We therefore analyzed the experience of this community neurology practice in treating acute strokes with IV tPA.

REVIEW SUMMARY

We retrospectively reviewed our treatment experience for 101 patients given IV tPA in one community neurology practice in 3 Cleveland-area hospitals between 1997 and 2003. Symptomatic hemorrhage occurred in 2 of 101 patients who received IV tPA. Median National Institutes of Health Stroke Scale (NIHSS) was 10.8 pretreatment, 3 at 24 hours, and 2.1 on hospital discharge. IV tPA treatment rate increased from 4.7% to 10.3% between 1999 and 2003.

CONCLUSION

IV tPA for acute ischemic stroke can be given safely and effectively by physicians in an independent neurology practice in the community hospital setting.

Results of a Multicentre, Randomised Controlled Trial of Intra-Arterial Urokinase in the Treatment of Acute Posterior Circulation Ischaemic Stroke

BACKGROUND

Patients with ischaemic stroke due to occlusion of the basilar or vertebral arteries may develop a rapid deterioration in neurological status leading to coma and often to death. While intra-arterial thrombolysis may be used in this context, no randomised controlled data exist to support its safety or efficacy.

METHODS

Randomised controlled trial of intra-arterial urokinase within 24 h of symptom onset in patients with stroke and angiographic evidence of posterior circulation vascular occlusion.

RESULTS

Sixteen patients were randomised, and there was some imbalance between groups, with more severe strokes occurring in the treatment arm. A good outcome was observed in 4 of 8 patients who received intra-arterial urokinase compared with 1 of 8 patients in the control group.

CONCLUSIONS

These results support the need for a large-scale study to establish the efficacy of intra-arterial thrombolysis for acute basilar artery occlusion.

[Long-term outcome of intrapleural fibrinolytic therapy via small-bore catheter drainage in the management of complicated parapneumonic effusion and empyema-a case series]

BACKGROUND AND PURPOSE

Complicated parapneumonic effusions (PPE) and pleural empyemas (PE) are associated with increased morbidity and mortality. Intrapleural fibrinolytic therapy (IFT) has been established, besides video-assisted thoracoscopy (VATS), in the management of PPE and PE. Combination of IFT and small-bore catheter drainage has previously not been investigated.

PATIENTS AND METHODS

15 patients consecutively referred for PPE and PE were managed with simultaneous IFT via small-bore catheter drainage (9, 12, 14 F). In addition to evaluation of primary outcome, lung function testing and radiologic studies were obtained after 3 months to predict potential pulmonary restrictive impairment and residual pleural thickening.

RESULTS

Primary outcome of all 15 patients was positive. Only one patient showed a significant residual pleural thickening. None of the patients showed a restrictive lung function pattern.

CONCLUSION

Proven applicability of IFT via small-bore catheter drainage seems to be effective in the face of long-term outcome. Further prospective and multicentric studies should be initiated to investigate the practicability of IFT via small-bore catheter drainage.

Hyperacute Therapy of Ischemic Stroke: Intravenous Thrombolysis

Stroke is the third most common cause of death in the United States following heart disease and cancer. Following the success of thrombolysis for myocardial infarction in the early 1990s, major trials for evaluation of this new therapeutic approach for ischemic stroke were initiated. The majority of ischemic strokes are due to occlusion of a cerebral vessel by a blood clot. Occlusion of a cerebral blood vessel leads to a core of infracted tissue surrounded by a relatively hypoperfused but viable brain tissue (the ischemic penumbra), which can be potentially salvaged by rapid recanalization of the target vessel. The underlying rationale for introduction of thrombolytic drugs is the lysis of an obliterating thrombus and reestablishment of blood flow. In this article we review the major intravenous thrombolysis trials leading to approval of intravenous recombinant tissue plasminogen activator, the only FDA approved treatment available today for acute ischemic stroke.

Vampire bat salivary plasminogen activator (desmoteplase) inhibits tissue-type plasminogen activator-induced potentiation of excitotoxic injury

BACKGROUND AND PURPOSE

In contrast to tissue-type plasminogen activator (tPA), vampire bat (Desmodus rotundus) salivary plasminogen activator (desmoteplase [DSPA]) does not promote excitotoxic injury when injected directly into the brain. We have compared the excitotoxic effects of intravenously delivered tPA and DSPA and determined whether DSPA can antagonize the neurotoxic and calcium enhancing effects of tPA.

METHODS

The brain striatal region of wild-type c57 Black 6 mice was stereotaxically injected with N-methyl-d-Aspartate (NMDA); 24 hour later, mice received an intravenous injection of tPA or DSPA (10 mg/kg) and lesion size was assessed after 24 hours. Cell death and calcium mobilization studies were performed using cultures of primary murine cortical neurons.

RESULTS

NMDA-mediated injury was increased after intravenous administration of tPA, whereas no additional toxicity was seen after administration of DSPA. Unlike DSPA, tPA enhanced NMDA-induced cell death and the NMDA-mediated increase in intracellular calcium levels in vitro. Moreover, the enhancing effects of tPA were blocked by DSPA.

CONCLUSIONS

Intravenous administration of tPA promotes excitotoxic injury, raising the possibility that leakage of tPA from the vasculature into the parenchyma contributes to brain damage. The lack of such toxicity by DSPA further encourages its use as a thrombolytic agent in the treatment of ischemic stroke.

Utilidad de la urocinasa intrapleural en el tratamiento del derrame pleural paraneumónico

INTRODUCTION

Intrapleural fibrinolytic instillation has been used in the treatment of loculated pleural effusions and empyemas and has reduced the need for surgical intervention. Currently, the most commonly used fibrinolytic is urokinase, although the doses have not yet been standardized in children. The aim of the present study was to evaluate the utility of urokinase in the treatment of infectious pleural effusions in children.

MATERIAL AND METHODS

A retrospective study was performed of children with infectious pleural effusions admitted to the pediatric intensive care unit (PICU) between January 2000 and December 2003. Age, sex, clinical features, laboratory tests, response to urokinase treatment and clinical course during hospital stay were analyzed.

RESULTS

Thirty-one children were treated. The mean age was 38.1 months (SD: 22). There were 18 boys and 13 girls. The most frequent month of diagnosis was November and the number of admission significantly increased from 2002 onwards. The most frequent antibiotic therapy used before admission to the PICU was cefotaxime associated with vancomycin (41 %), followed by cefotaxime alone (16 %). Positive cultures for Streptococcus pneumoniae were found in 11 patients (35 %). Pleural loculation was found in 14 patients (45 %). Treatment with intrapleural urokinase was used in 23 patients (74 %). The mean chest tube drainage was 140 ml (SD: 175) in the 24 hours before urokinase instillation and was 406 ml (SD: 289) in the 48 hours after fibrinolytic therapy (p < 0.05). Twenty-one patients (91 %) who received urokinase treatment had a good response. There were no complications during the treatment. The mean length of stay in the PICU was 5.8 days (SD: 2.6).

CONCLUSIONS

The incidence of complicated pleural effusions due to S. pneumoniae has increased in the last few years, despite antibiotic therapy. Intrapleural urokinase is an effective treatment, including in empyemas without loculation. None of our patients required thoracotomy and there were few adverse effects.

A Case-Control Analysis of Intra-Arterial Urokinase Thrombolysis in Acute Cardioembolic Stroke

BACKGROUND

Intra-arterial urokinase (IA-UK) thrombolysis is frequently given in Japan to selected patients with acute cerebral artery occlusion. However, it is not clear whether or not IA-UK thrombolysis has an efficacy for acute stroke patients. The purpose of this study was to assess the effects of IA-UK thrombolysis in acute cardioembolic stroke patients, by performing a case-control analysis using data from Japan's Multicenter Stroke Investigator's Collaboration (J-MUSIC).

METHODS

16,922 acute ischemic stroke patients were enrolled into J-MUSIC. From these patients, we selected 91 patients (UK group) who met the following criteria: treatment with IA-UK; 20-75 years of age; cardioembolic stroke; presenting with a carotid stroke; admission within 4.5 h of symptom onset, and a National Institutes of Health Stroke Scale (NIHSS) score of 5-22 points on admission. A control group of 182 patients without IA-UK treatment and matched to the NIHSS score, gender, and age was chosen. We compared the modified Rankin scale (mRS) score at discharge and the mortality between the 2 groups.

RESULTS

In both groups, the mean age was 65 +/- 8 years, and the median NIHSS score was 14. The mean interval between symptom onset and UK administration was 3.4 +/- 1.3 h, and the IA-UK dose was 392,000 +/- 200,000 units. The mRS score at discharge was lower in the UK group than in the control group (mean, SD, median; 2.8, 2.9, 2 in UK group vs. 3.3, 1.8, 4, in the control, respectively p = 0.031). A favorable outcome (mRS of 0-2) was more frequently observed in the UK group (50.5%) than in the control group (34.1%, p = 0.0124). No difference in the mortality rate was seen between the UK group (11.0%) and the control group (13.3%). As well, there was no difference in the length of hospital stay between the UK group (46 +/- 41 days, mean +/- SD) and the control group (42 +/- 42 days, mean +/- SD).

CONCLUSIONS

IA-UK thrombolytic therapy may improve the outcome in hyperacute cardioembolic stroke patients.

Rescue use of endovascular snare for acute basilar artery embolic occlusion resistant to balloon angioplasty and fibrinolysis therapy

A rescue clot disruption using a basket snare is described for acute basilar artery embolic occlusion resistant to balloon angioplasty and fibrinolysis therapy. In spite of failed balloon angioplasty in conjunction with fibrinolysis, a basket-shaped snare connected to a microguide wire could be used to catch and crush the clot in the upper basilar artery. The rescue use of a snare may be effective for angioplasty-resistant acute embolic stroke.

Use of intraperitoneal urokinase for resistant bacterial peritonitis in continuous ambulatory peritoneal dialysis

Intraperitoneal (IP) urokinase is a fibrinolytic agent that has been used in the adjunctive treatment of continuous ambulatory peritoneal dialysis (CAPD) and resistant and relapsing peritonitis. However, its efficacy and role in treating resistant CAPD bacterial peritonitis remain unclear and results from previous prospective studies have been conflicting. We prospectively randomized 88 CAPD patients with bacterial peritonitis resistant to initial empirical IP antibiotics into two groups: IP urokinase 60,000 IU and a placebo group. Patients were treated concomitantly with susceptible antibiotics according to culture results. Peritoneal dialysate grew pseudomonas aeruginosa in 13 patients (14.8%), non-pseudomonas bacteria in 63 patients (71.6%) and negative cultures in 12 patients (13.6%). For the clinical outcomes, there were no significant differences in the primary response rates (61.4 vs. 50%), relapse rates (9.1 vs. 13.6%), Tenckhoff catheter removal rates (22.7 vs. 29.5%) and mortality rates (6.8 and 6.8%) between the urokinase group and the controls (p=ns). Subgroup analysis of culture negative patients (n=12) also demonstrated no sgnificant benefit for urokinase treatment. No significant adverse effects were encountered with the IP urokinase instillation. Total median peritonitis-related length of hospitalization for the urokinase group and controls were 7 and 11 days, respectively (p=0.32). We concluded that IP urokinse plays no significant role as an adjuvant therapy in the treatment of bacterial CAPD peritonitis resistant to initial IP antibiotic therapy.