[Efficacy of intravenous thrombolysis for acute severe cerebral infarction and risk factors of poor prognosis: a randomized controlled trial in 152 cases]

OBJECTIVE

To investigate the clinical efficacy and safety of intravenous thrombolysis in patients with acute severe cerebral infarction and analyze the risk factors of poor prognosis after thrombolysis.

METHODS

This randomized controlled trial was conducted among 152 patients with acute severe cerebral infarction, with the onset time all within 4.5 h. The patients were randomized into control group (76 cases) and observation group (76 cases) and received treatment with routine therapy (antiplatelet aggregation, statins, neuroprotection and drugs that stimulate blood flow) and intravenous thrombolytic therapy with alteplase in addition to the routine therapy, respectively. The NIHSS scores were recorded at 24 h, 1 week and 1 month after the treatment. The mRS scores at 3 months and the incidence of symptomatic intracranial hemorrhage at one week after the treatment were compared between the two groups. According to mRS scores at 3 months, the patients in the observation group were divided into good prognosis group (30 patients) and poor prognosis group (46 patients), and the risk factors for poor prognosis were analyzed using univariate and multivariate Logistic regression analysis.

RESULTS

At 24 h, 1 week and 1 month after the treatment, the reduction of NIHSS scores was more significant in the observation group than in the control group (F=24.684, P < 0.001). At 3 months after the treatment, the mRS scores were significantly lower (t=4.396, P < 0.001) and the good prognosis rate was significantly higher (χ2=13.636, P < 0.001) in the observation group than those of the control group. Symptomatic intracranial hemorrhage occurred in 4 cases in the observation group and in 2 cases in the control group within 1 week after the treatment (χ2=0.694, P=0.405). The time from onset to thrombolysis (OR=0.173, P=0.035), prethrombolytic systolic pressure (OR=0.869, P=0.019) and baseline NIHSS score (OR=0.466, P=0.011) were identified as independent risk factors for poor prognosis after intravenous thrombolysis.

CONCLUSION

Intravenous thrombolysis is effective and safe for patients with acute severe cerebral infarction, and the time from onset to thrombolysis, prethrombolytic systolic pressure and baseline NIHSS score are independent risk factors for a poor prognosis after intravenous thrombolysis.

Recanalization of Chronic Occlusion of the Middle Cerebral Artery With Tissue Plasminogen Activator Treatment: A Case Report

OBJECTIVES

Patients with chronic proximal middle cerebral artery (MCA) occlusion do not present with severe symptoms, but early recanalization of acute occlusion is associated with high morbidity and mortality. Tissue plasminogen activator (tPA) is a recombinant thrombolytic agent approved for treating ischemic stroke, although only a few cases of tPA administration in chronic MCA occlusion have yielded positive results.

METHODS

A 71-year-old patient had a history of right MCA territorial infarction with the occlusion occurring 12 years ago (November 2005). Although the patient was treated with antiplatelet agents, MCA recanalization was not achieved. The patient was referred to our hospital again (January 2017) for newly discovered symptoms. We immediately administered tPA because the patient presented 2 hours after onset of symptoms.

RESULTS

Neurological symptoms resolved within 24 hours of treatment, and magnetic resonance angiography confirmed recanalization of the right MCA territorial lesion. No neurological abnormalities were observed during the 12-week follow-up.

CONCLUSIONS

At present, tPA is the only approved treatment for acute ischemic stroke, although it presents a limited time frame to avoid severe medication-related adverse effects. Our report suggests nonatherosclerotic chronic MCA occlusion as an alternative application of tPA therapy.

Short and long-term outcomes after combined intravenous thrombolysis and mechanical thrombectomy versus direct mechanical thrombectomy: a prospective single-center study

Recent clinical trials demonstrated that mechanical thrombectomy (MT) using second-generation endovascular devices has beneficial effects in acute ischemic stroke (AIS) due to large vessel occlusion (LVO). However, it remains controversial if intravenous thrombolysis (IVT) prior to MT is superior compared to direct mechanical thrombectomy (DMT). The aims of this study were to compare short and long-term outcomes between IVT + MT and DMT patients. We prospectively recruited AIS patients with LVO in the anterior or posterior circulation eligible for MT with and without prior IVT. Modified Rankin Scale (mRS) and mortality were assessed at baseline, at discharge, 90-days and 1-year after stroke. Favorable outcome was defined as a mRS score ≤2. Of the 66 patients included, 33 (50%) were in IVT + MT group and 33 (50%) were in DMT group. Except for a higher prevalence of patients using anticoagulants at admission in DMT group, baseline characteristics did not differ in the two groups. Procedural characteristics were similar in IVT + MT and DMT group. Rate of favorable outcome was significantly higher in IVT + MT patients than DMT ones both 90-days (51.5 vs. 18.2%; p = 0.004) and 1-year (51.5 vs. 15.2%; p = 0.002) after stroke. DMT patients were six times more likely to die during the 1-year follow-up compared to IVT + MT patients. This study suggests that bridging therapy may improve short and long-term outcomes in patients eligible for endovascular treatment. Further studies with larger patient numbers and randomized design are needed to confirm our findings.

Comparison of Outcomes After Mechanical Thrombectomy Alone or Combined with Intravenous Thrombolysis and Mechanical Thrombectomy for Patients with Acute Ischemic Stroke due to Large Vessel Occlusion

BACKGROUND

Whether intravenous thrombolysis (IVT) before mechanical thrombectomy (MT) provides additional benefits remains controversial. We aimed to compare clinical and radiologic outcomes between IVT+MT and MT alone groups.

METHODS

We retrospectively reviewed the clinical and radiological features of patients from the prospectively collected database who sustained anterior circulation stroke due to large vessel occlusion (LVO) and were treated with MT within 8 hours of symptom onset. We compared rates of successful reperfusion, functional independence and mortality at 90 days, and symptomatic intracranial hemorrhage (sICH) as clinical endpoints between the 2 groups.

RESULTS

The 81 patients included in this study included 38 (46.9%) in the MT alone group (mean age, 72.6 ± 14.1 years; 17 males [44.7%]) and 43 in the IVT+MT group (mean age, 68.9 ± 12.8 years; 29 males [67.4%]). There were no significant differences in patient baseline characteristics between the 2 groups except for a male predominance in the IVT+MT group. The mean interval from onset to groin puncture (221.6 ± 110.5 minutes vs. 204.7 ± 63.7 minutes; P = 0.472) and the rate of successful reperfusion rate (thrombolysis in cerebral infarction 2b/3, 60.5% vs. 58.1%; P = 0.827) did not differ significantly between the MT and IVT+MT groups. The rate of favorable functional outcome, as determined by a modified Rankin Scale score 0-2 (36.8% vs. 51.2%; P = 0.263) and mortality at 90 days (18.4% vs. 9.3%; P = 0.332), and the rate of sICH (5.3% vs. 4.6%; P = 1.000) were also not significantly different between the 2 groups.

CONCLUSIONS

This study suggests that previous IVT might not facilitate successful reperfusion and favorable functional outcomes in patients with anterior circulation stroke treated with MT. MT alone can be a safe and effective treatment modality in patients who are ineligible for IVT for various reasons.

Ischaemic stroke and the recanalization drug tissue plasminogen activator interfere with antibacterial phagocyte function

Background

Stroke induces immune alterations such as impaired oxidative burst and reduced release of neutrophil extracellular traps (NETs). We hypothesised that key enzymes of these defence mechanisms may be altered in ischaemic stroke. Therefore, we analysed the intra- and extracellular amounts of myeloperoxidase (MPO) and neutrophil elastase (NE) in patient sera and granulocytes and monocytes. Because the autonomous nervous system is thought to mediate stroke-induced immune alterations, we also studied the influence of stress hormones and acetylcholine on MPO and NE.

Rapid recanalization by recombinant tissue plasminogen activator (r-tPA) is the only available treatment for ischaemic stroke besides thrombectomy, and its influence on antibacterial defence mechanisms of granulocytes and monocytes were addressed here.

Methods

Ex vivo: Intracellular and serum MPO and NE were measured on days 0, 1, 3 and 5 post-stroke by either flow cytometry or enzyme-linked immunosorbent assay (ELISA) and compared to controls. In vitro: Blood from healthy donors was incubated with catecholamines, dexamethasone and acetylcholine, and the percentage of NET-producing cells and the area covered by NETs were quantified immunohistochemically. Intra- and extracellular MPO and NE were quantified by flow cytometry or ELISA. Blood samples from healthy donors were incubated with r-tPA, and oxidative burst, phagocytosis, NETosis, cytokine release, MPO and NE were quantified by flow cytometry, ELISA and microscopy.

Results

MPO was reduced in granulocytes but increased in sera obtained from stroke patients compared to controls. NE was not altered intracellularly but was elevated in patient sera. The percentage of NET-producing neutrophils was decreased by stress hormones and increased by acetylcholine. Neither intracellular MPO nor NE was altered by hormone treatment; however, adrenaline and acetylcholine induced NE release.

r-tPA led to reduced phagocytosis and oxidative burst in granulocytes and monocytes in vitro. NETosis, MPO release and cytokines were not altered, whereas NE release was enhanced by r-tPA.

Conclusions

Intracellular reduction of MPO might be responsible for reduced NETosis in stroke patients. The impact of enhanced MPO and NE serum levels in stroke patients should be addressed in future studies.

r-tPA impaired antibacterial defence function in vitro. Therefore, patients who undergo unsuccessful recanalization therapy might be at higher risk for infection, which should be analysed in future investigations. Immune alterations due to r-tPA effects in stroke patients should also be investigated.

Electronic supplementary material

The online version of this article (doi:10.1186/s12974-017-0914-6) contains supplementary material, which is available to authorized users.

Alteplase Reduces Downstream Microvascular Thrombosis and Improves the Benefit of Large Artery Recanalization in Stroke

BACKGROUND AND PURPOSE

Downstream microvascular thrombosis (DMT) is known to be a contributing factor to incomplete reperfusion in acute ischemic stroke. The aim of this study was to determine the timing of DMT with intravital imaging and to test the hypothesis that intravenous alteplase infusion could reduce DMT in a transient middle cerebral artery occlusion (MCAO) rat stroke model.

METHODS

Rats were subjected to 60-minute transient MCAO. Alteplase (10 mg/kg) was administered 30 minutes after the beginning of MCAO. Real-time intravital fluorescence microscopy through a dura-sparing craniotomy was used to visualize circulating blood cells and fibrinogen. Cerebral microvessel patency was quantitatively evaluated by fluorescein isothiocyanate-dextran perfusion.

RESULTS

Immediately after MCAO, platelet and leukocyte accumulation were observed mostly in the venous compartment. Within 30 minutes after MCAO, microthrombi and parietal fibrin deposits were detected in postcapillary microvessels. Alteplase treatment significantly (P=0.006) reduced infarct volume and increased the percentage of perfused vessels during MCAO (P=0.02) compared with saline. Plasma levels of fibrinogen from alteplase-treated rats showed a rapid and profound hypofibrinogenemia. In vitro platelet aggregation demonstrated that alteplase reduced platelet aggregation (P=0.0001) and facilitated platelet disaggregation (P=0.001). These effects were reversible in the presence of exogenous fibrinogen.

CONCLUSIONS

Our data demonstrate that DMT is an early phenomenon initiated before recanalization. We further show that alteplase-dependent maintenance of downstream perfusion during MCAO improves acute ischemic stroke outcome through a fibrinogen-dependent platelet aggregation reduction. Our results indicate that early targeting of DMT represents a therapeutic strategy to improve the benefit of large artery recanalization in acute ischemic stroke.

Imaging predictors of outcome following intravenous thrombolysis in acute stroke

Intravenous tissue plasminogen activator is the only approved medical treatment for patients with acute ischemic stroke. While it is associated with excellent clinical outcome in about 30 %, even with timely thrombolysis administration, certain strokes continue to evolve and lead to poor outcomes. Several studies have attempted to identify predictors of outcome despite timely thrombolysis. Persistence of a proximal clot burden and large vessel occlusion following thrombolysis are markers for patients who may potentially benefit from advanced treatment modalities like intra-arterial thrombolysis and thrombectomy. Timely brain imaging and interpretation play a crucial role in providing these treatment decisions. In this review, various imaging predictors of poor outcome among patients with acute ischemic stroke treated with intravenous thrombolysis are outlined. Despite identification of these imaging predictors, thrombolysis should not be withheld, as it may still be beneficial in a subset of patients. Knowledge of these predictors may set benchmarks for selecting candidates who may potentially benefit from advanced management strategies in future trials.

Pro-inflammatory mediators and apoptosis correlate to rt-PA response in a novel mouse model of thromboembolic stroke

BACKGROUND

A recent study suggests that patients with persistent occlusion of the middle cerebral artery (MCA) following treatment with recombinant tissue plasminogen activator (rt-PA) have better outcomes than patients with MCA occlusion not receiving rt-PA. We performed a study to elucidate possible mechanisms of this finding in a new model of thromboembolic stroke closely mimicking human pathophysiology.

METHODS

Thromboembolic stroke was induced by local injection of thrombin directly into the right MCA of C57 black/6J mice. Rt-PA was administered 20 and 40 min after clot formation. The efficiency of rt-PA to induce thrombolysis was measured by laser Doppler. After 24 h, all animals were euthanized and interleukin (IL)-6, tumor necrosis factor-alpha (TNF-α), matrix metalloproteinase (MMP)-9, Caspase-3, hsp 32 and hsp 70 protein levels were investigated by immunofluorescence. Presence of hemorrhage was verified and infarct volume was measured using histology.

RESULTS

Thrombin injection resulted in clot formation giving rise to cortical brain infarction. Early rt-PA treatment starting at 20 min after the clot formation resulted in 100% recanalization. However, rt-PA-induced thrombolysis dissolved the clot in only 38% of the animals when administered 40 min after clot formation. Protein levels of IL-6, TNF-α, MMP-9, Caspase-3, hsp 32 and hsp 70 were increased after MCAO, whereas treatment with rt-PA attenuated the expressions of inflammatory markers in those animals where the thrombolysis was successful. In addition, the infarct size was significantly reduced with rt-PA treatment compared to non-treated MCAO, regardless of whether MCA thrombolysis was successful.

CONCLUSIONS

The present study demonstrates a clear correlation of the protein expression of inflammatory mediators, apoptosis and stress genes with the recanalization data after rt-PA treatment. In this model rt-PA treatment decreases the infarct size regardless of whether vessel recanalization is successful.

Thrombolysis in patients with lacunar stroke is safe: an observational study

Research suggests that the etiology of lacunar stroke is different from that of other stroke subtypes. This could imply an altered response to thrombolysis, but data concerning the efficacy of rt-PA in lacunar stroke is limited and inconsistent. From our prospectively collected stroke database, we identified patients with an MRI-confirmed purely lacunar stroke that were treated in our Stroke Unit between 2004 and 2011. We compared both the clinical course (NIHSS, deterioration, mRS at 3 months) and the MRI findings between patients who either received or did not receive rt-PA. In comparison to patients who obtained standard medical care (n = 468), acute lacunar stroke patients treated with rt-PA (n = 69) were more severely affected on admission (median NIHSS of 5 vs. 3; p < 0.001) and presented less frequently with a lacunar syndrome (74 vs. 88 %; p = 0.003). The clinical course was more favorable in patients treated with rt-PA (median NIHSS improvement of 3 vs. 1; p < 0.001), while functional deficit after 3 months was similar in both groups (median mRS of 2; p = 0.211). Overall complication rates did not differ significantly between the two groups, but while we did not detect symptomatic intracranial hemorrhage, hemorrhagic transformation was more frequent in thrombolyzed patients (11.6 vs. 1.9 %; p = 0.001). Patients with acute lacunar stroke benefited from thrombolysis without additional complications. Thus, patients with suspected acute lacunar stroke or lacunar syndrome should not be treated differently than other stroke populations.

Tissue plasminogen activator prevents mortality from sulfur mustard analog-induced airway obstruction

Sulfur mustard (SM) inhalation causes the rare but life-threatening disorder of plastic bronchitis, characterized by bronchial cast formation, resulting in severe airway obstruction that can lead to respiratory failure and death. Mortality in those requiring intubation is greater than 80%. To date, no antidote exists for SM toxicity. In addition, therapies for plastic bronchitis are solely anecdotal, due to lack of systematic research available to assess drug efficacy in improving mortality and/or morbidity. Adult rats exposed to SM analog were treated with intratracheal tissue plasminogen activator (tPA) (0.15-0.7 mg/kg, 5.5 and 6.5 h), compared with controls (no treatment, isoflurane, and placebo). Respiratory distress and pulse oximetry were assessed (for 12 or 48 h), and arterial blood gases were obtained at study termination (12 h). Microdissection of fixed lungs was done to assess airway obstruction by casts. Optimal intratracheal tPA treatment (0.7 mg/kg) completely eliminated mortality (0% at 48 h), and greatly improved morbidity in this nearly uniformly fatal disease model (90-100% mortality at 48 h). tPA normalized plastic bronchitis-associated hypoxemia, hypercarbia, and lactic acidosis, and improved respiratory distress (i.e., clinical scores) while decreasing airway fibrin casts. Intratracheal tPA diminished airway-obstructive fibrin-containing casts while improving clinical respiratory distress, pulmonary gas exchange, tissue oxygenation, and oxygen utilization in our model of severe chemically induced plastic bronchitis. Most importantly, mortality, which was associated with hypoxemia and clinical respiratory distress, was eliminated.

Selection of possible responders to thrombolytic therapy in acute ischemic stroke

Ischemic stroke is one of the leading causes of death and morbidity worldwide, and systemic thrombolytic treatment is still the first-line therapy within 4.5 h from symptom onset. Selecting patients for treatment response is mandatory in any time window but challenging as well. The authors aim to support stroke physicians in their individual decision making. Besides evidence from clinical trials, some suggestions included here exclusively reflect the authors' opinions. This article presents clinical and imaging criteria of selecting patients reasonably, offering causal therapy to a growing number of patients.