Safety of intravenous fibrinolysis in imaging-confirmed single penetrator artery infarcts

Efficacy and Safety of Intravenous rtPA in Ischemic Strokes Due to Small-Vessel Occlusion: Systematic Review and Meta-Analysis

Intravenous recombinant tissue plasminogen activator (iv-rtPA) has been routinely used to treat ischemic stroke for 25 years, following large clinical trials. However, there are few prospective studies on the efficacy and safety of this therapy in strokes attributed to cerebral small vessel disease (SVD). We evaluated functional outcome (modified Rankin scale, mRS) and symptomatic intracerebral hemorrhage (sICH) using all available data on the effects of iv-rtPA in SVD-related ischemic stroke (defined either using neuroimaging, clinical features, or both). Using fixed-effect and random-effects models, we calculated the pooled effect estimates with regard to excellent and favorable outcomes (mRS=0-1 and 0-2 respectively, at 3 months), and the rate of sICH. Twenty-three studies fulfilled the eligibility criteria, 11 of which were comparative, and there were only 3 randomized clinical trials. In adjusted analyses, there was an increased odds of excellent outcome (adjusted OR=1.53, 95% CI: 1.29-1.82, I2: 0%) or favorable outcome (adjusted OR=1.68, 95% CI: 1.31-2.15,I2: 0%) in patients who received iv-rtPA compared with placebo. Across the six studies which reported it, the incidence of sICH was higher in the treatment group (M-H RR = 8.83, 95% CI: 2.76-28.27). The pooled rate of sICH in patients with SVD administered iv-rtPA was only 0.72% (95% CI: 0.12%-1.64%). We conclude that when ischemic stroke attributed to SVD is considered separately, available data on the effects of iv-rtPA therapy are insufficient for the highest level of recommendation, but it seems to be safe. Although further therapeutic trials in SVD-related ischemic stroke appear to be justified, our findings should not prevent its continued use for this group of patients in clinical practice.

Factors Associated with Hemorrhagic Transformation in Infarctions Involving the Posterior Circulation System

BACKGROUNDS AND PURPOSE

Hemorrhagic transformation (HT) following stroke of the posterior circulation is a rare occurrence, and its risk factors remain relatively unknown. This study aimed at examining the rate of HT and its risk factors in patients enduring acute ischemic stroke in the territories of the vertebral, basilar, and posterior-cerebral arteries.

MATERIALS AND METHODS

A total of 217 consecutive patients the risk factors for ischemic stroke were recorded and comprehensive biochemical, cardiac assessments, and neuroimaging were performed. National Institutes of Health Stroke Scale (NIHSS) scores were calculated for each patient. Those with HT as documented with neuroimaging based on the European Cooperative Acute Stroke Study criteria and potential risk factors were assessed.

RESULTS

There were 217 participants with a mean age of 67.33 ± 12.44 years. Among 17 patients (7.8%) developing HT, 8 (47%) had parenchymal hematoma, and 9(53.5%) had hemorrhagic infarction. Cardioembolism was the most frequent etiological factor both in the overall group (31.0%) as well as in those with HT (41.2%). Factors that emerged as significant predictors of HT included high systolic (odds ratio [OR] 1.14; 95% confidence interval [CI] 1.08-1.20; P< .001) and diastolic blood pressure (P= .001) on the day of admission and the infarction volume of greater than or equal to 3.60 ± 3.29 cm³(OR 1.00, 95% CI 1.00-1.01; P< .001). While NIHSS scores were not significantly different on Day 1, HT patients had higher NIHSS scores at Day 10(OR 1.22; 95% CI 1.09-1.36; P< .001), and this difference was also reflected in mRS at the end of the 3 month period.

CONCLUSION

HT is a rare complication of the infarction of the posterior circulation that is associated with increased morbidity and mortality. Identification of predictive factors for HT in patients with the acute infarction of the posterior circulation may facilitate patient selection for thrombolytic treatment.

Intravenous thrombolysis with tissue-plasminogen activator in small vessel occlusion

Intravenous tissue-plasminogen activator (IV-TPA) treatment in acute ischemic stroke (AIS) patients due to small vessel occlusion (SVO) has been debated because of its small expected benefit and symptomatic intracranial hemorrhage (SICH) risk. Furthermore, data on subgroups of SVO patients are limited. From a prospective multicenter stroke registry database, AIS patients due to SVO within 24 h from onset were selected. Efficacy outcomes were 3-month modified Rankin Scale (mRS) score 0-1 proportion and mRS score distribution. Additionally, subgroup analyses were conducted by age, sex, initial National Institute Health Stroke Scale (NIHSS) score, and presenting limb paresis. This study included 2482 patients: 193 in the IV-TPA group and 2289 in the control group. After adjusting covariates, IV-TPA treatment was associated with an increased mRS 0-1 outcome (adjusted OR [95% CI], 1.56 [1.06-2.29]; P = 0.0249), but was not significantly associated with a favorable mRS shift (1.33 [0.98-1.81]; P = 0.0709). SICH and 3-month death occurred in three (1.6%) and none in the IV-TPA group versus one (0.04%) and 16 (0.7%) in the control group. In subgroup analyses, the IV-TPA effect appeared significantly greater in patients aged ≥80 versus <80 for mRS score distribution (P_interaction = 0.012). This study showed that, in SVO patients, IV-TPA within 4.5 h may improve functional outcome with a low SICH risk. The benefit appeared more substantial in patients aged ≥80.

Outcome after intravenous thrombolysis in patients with acute lacunar stroke: An observational study based on SITS international registry and a meta-analysis

BACKGROUND

Intravenous thrombolysis (IVT) for lacunar stroke (LS) is debated, as the underlying pathophysiological mechanism may not be thrombogenic.

AIMS

To investigate outcomes after IVT in LS in the SITS International Stroke Thrombolysis Register and perform a meta-analysis.

METHODS

LS was identified by both baseline NIHSS-subscores and discharge ICD-10 codes, and contrasted by IVT to non-IVT treated. IVT patients were predominantly from Europe, non-IVT patients predominantly from South America and Asia. Outcome measurements were functional independence (modified Rankin Scale [mRS] score ≤2), excellent outcome (mRS ≤ 1), and mortality at three months. Matched-control comparisons of symptomatic intracerebral hemorrhage (SICH) between IVT-treated LS and IVT-treated non-LS patients were performed. Additionally, we performed a meta-analysis.

RESULTS

Median age for IVT-treated LS patients (n = 4610) was 66 years vs. 64 years and NIHSS score was 6 vs. 3, compared to non-IVT-treated LS (n = 1221). Univariate outcomes did not differ; however, IVT-treated LS patients had higher adjusted odds ratios (aOR) for functional independence (aOR = 1.65, 95% CI = 1.28-2.13) but similar mortality at three months (aOR = 0.57, 0.29-1.13) than non-IVT-LS. Propensity-score matched analysis showed that IVT-treated LS patients had a 7.1% higher chance of functional independency than non-IVT LS patients (p < 0.001). IVT-treated LS patients had lower odds for SICH (aOR = 0.33, 0.19-0.58 per SITS, aOR = 0.40, 0.27-0.57 per ECASS-2) than matched non-LS controls, which was mirrored in the meta-analysis.

CONCLUSIONS

Our adjusted results show that IVT treatment in LS patients was associated with better functional outcome than non-IVT-treated LS and less SICH than IVT-treated non-LS patients.

Multimodal CT provides improved performance for lacunar infarct detection

BACKGROUND AND PURPOSE

Lacunar infarcts account for approximately 25% of acute ischemic strokes. Compared with NCCT alone, the addition of CTP improves sensitivity for detection of infarcts overall. Our aim was to systematically evaluate the diagnostic benefit and interobserver reliability of an incremental CT protocol in lacunar infarction.

MATERIALS AND METHODS

Institutional review board approval and patient consent were obtained. One hundred sixty-three patients presenting with a lacunar syndrome ≤4.5 hours from symptom onset were enrolled. Images were reviewed incrementally by 2 blinded readers in 3 separate sessions (NCCT only, NCCT/CTA, and NCCT/CTA/CTP). Diagnostic confidence was recorded on a 6-point scale with DWI/ADC as a reference. Logistic regression analysis calculated differences between actual and observed diagnoses, adjusted for confidence. Predictive effects of observed diagnostic accuracy and confidence score were quantified with the entropy r(2) value. Sensitivity, specificity, and confidence intervals were calculated accounting for multiple readers. Receiver operating characteristic analyses were compared among diagnostic strategies. Interobserver agreement was established with Cohen κ statistic.

RESULTS

The final study cohort comprised 88 patients (50% male). DWI/ADC-confirmed lacunar infarction occurred in 59/88 (67%) with 36/59 (61%) demonstrating a concordant abnormal finding on CTP. Sensitivity for definite or probable presence of lacunar infarct increased significantly from 9.3% to 42.4% with incremental protocol use, though specificity was unchanged (range, 91.9%-95.3%). The observed diagnosis was significantly related to the actual diagnosis after adjusting for CTP confidence level (P = .04) and was 5.1 and 2.4 times more likely to confirm lacunar infarct than NCCT or CTA source images. CTP area under the curve (0.77) was significantly higher than that of CTA source images (0.68, P = .006) or NCCT (0.55, P < .001).

CONCLUSIONS

CTP offers an improved diagnostic benefit over NCCT and CTA for the diagnosis of lacunar infarction.

Cardioembolic stroke diagnosis using blood biomarkers

Stroke is one of the main causes of death and disability in the world. Cardioembolic etiology accounts for approximately one fifth of all ischemic strokes whereas 25-30% remains undetermined even after an advanced diagnostic workup. Despite there is not any biomarker currently approved to distinguish cardioembolic stroke among other etiologies in clinical practice the use of biomarkers represents a promising valuable complement to determine stroke etiology reducing the number of cryptogenic strokes and aiding in the prescription of the most appropriated primary and secondary treatments in order to minimize therapeutic risks and to avoid recurrences. In this review we present an update about specific cardioembolic stroke-related biomarkers at a protein, transcriptomic and genetic level. Finally, we also focused on reported biomarkers associated with atrial fibrillation (a cardiac illness strongly related with cardioembolic stroke subtype) thus with a potential to become biomarkers to detect cardioembolic stroke in the future.

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.

Diffusion- and perfusion-weighted imaging in acute lacunar infarction: is there a mismatch?

PURPOSE

Characterization of lacunar infarction (LI) by use of multimodal MRI including diffusion- and perfusion-weighted imaging (DWI, PWI) is difficult because of the small lesion size. Only a few studies evaluated PWI in LI and the results are inconsistent.

METHODS

In 16 LI patients who underwent initial MRI within 6 hours after symptom onset and follow-up MRI within 1 week demographics, clinical presentation, and MRI findings were analyzed with special emphasis on DWI and PWI findings. Time to peak maps were classified as showing a normal perfusion pattern or areas of hypoperfusion which were further categorized in mismatch (PWI>DWI), inverse mismatch (PWI<DWI), and match (PWI=DWI). Quantitative perfusion maps were generated and analyzed by use of Signal Processing in NMR-Software (SPIN).

RESULTS

Of the 16 patients (mean age 65.5±12.9 years), 14 (87.5%) were male. Clinical symptoms comprised dysarthria (50%), hemiparesis (81.3%), and hemihypaesthesia (18.8%). Intravenous thrombolysis was performed in 7 (43.8%) patients. Clinical improvement was observed in 12 patients (75 %), while 2 (12.5%) patients showed a deterioration and another 2 (12.5%) a stable course. Acute ischemic lesions (mean volume of 0.46±0.29 cm³) were located in the thalamus (n=8, 50%), internal capsule (n=4, 25%), corona Radiata (n=3, 18.8%) and the mesencephalon (n=1, 6.3%). Circumscribed hypoperfusion (mean volume 0.61±0.48 cm³) was evident in 10 (62.5%) patients. Of these, 3 patients demonstrated a match, 4 an inverse mismatch, and 3 a mismatch between DWI and PWI lesion. Mean CBF and CBV ratios were 0.65±0.28 and 0.84±0.41 respectively. Growth of DWI lesions was observed in 7 (43.8%) and reversal of DWI lesions in 3 (18.8%) patients.

CONCLUSIONS

MRI allows identification of different DWI and PWI patterns in LI, including growth and reversal of ischemic lesions. Consequently, it may serve for a better characterization of this stroke subtype and support treatment decisions in daily clinical practice.

The exact science of stroke thrombolysis and the quiet art of patient selection

The science of metric-based patient stratification for intravenous thrombolysis, revolutionized by the landmark National Institute of Neurological Disorders and Stroke trial, has transformed acute ischaemic stroke therapy. Recanalization of an occluded artery produces tissue reperfusion that unequivocally improves outcome and function in patients with acute ischaemic stroke. Recanalization can be achieved mainly through intravenous thrombolysis, but other methods such as intra-arterial thrombolysis or mechanical thrombectomy can also be employed. Strict guidelines preclude many patients from being treated by intravenous thrombolysis due to the associated risks. The quiet art of informed patient selection by careful assessment of patient baseline factors and brain imaging could increase the number of eligible patients receiving intravenous thrombolysis. Outside of the existing eligibility criteria, patients may fall into therapeutic 'grey areas' and should be evaluated on a case by case basis. Important factors to consider include time of onset, age, and baseline blood glucose, blood pressure, stroke severity (as measured by National Institutes of Health Stroke Scale) and computer tomography changes (as measured by Alberta Stroke Programme Early Computed Tomography Score). Patients with traditional contraindications such as wake-up stroke, malignancy or dementia may have the potential to receive benefit from intravenous thrombolysis if they have favourable predictors of outcome from both clinical and imaging criteria. A proportion of patients experience complications or do not respond to intravenous thrombolysis. In these patients, other endovascular therapies or a combination of both may be used to provide benefit. Although an evidence-based approach to intravenous thrombolysis for acute ischaemic stroke is pivotal, it is imperative to examine those who might benefit outside of protocol-driven practice.

Progressive lacunar stroke: review of mechanisms, prognostic features, and putative treatments

Lacunar stroke is generally considered to have a fair outcome. However 20-30% of patients with lacunar stroke worsen neurologically in hours or days after onset, reaching eventually an unexpectedly severe disability status. In the field of acute stroke, progressive lacunar stroke remains an important unresolved practice problem, because as yet no treatment does exist proven to prevent or halt progression. Pathophysiology of progression is yet incompletely understood. Hemodynamic factors, extension of thrombosis, excitotoxicity, and inflammation, have been proposed as possible mechanisms of progression. A few clinical studies also aimed at establishing presentation features that may help identifying patients at risk of deterioration. In this paper, we review hypothesized mechanisms of lacunar stroke progression and possible markers of early deterioration. Moreover, based on putative mechanisms and suggestions from reported evidence, we propose a few treatments that seem worthy to be tested by randomized clinical trials.

Improving reperfusion therapy for acute ischaemic stroke

BACKGROUND

The first generation of clinical reperfusion treatment, intravenous (IV) fibrinolysis with tissue plasminogen activator (tPA), was a transformative breakthrough in stroke care, but is far from ideal.

OBJECTIVES

TO survey emerging strategies to increase the efficacy and safety of cerebral reperfusion therapy.

METHODS

Narrative review.

RESULTS AND CONCLUSIONS

Innovative IV pharmacologic reperfusion strategies include: extending IV tPA use to patients with mild deficits; developing novel fibrinolytic agents (tenecteplase, desmetolplase, plasmin); using ultrasound to enhance enzymatic fibrinolysis; combination clot lysis therapies (fibrinolytics with GPIIb/IIIa agents or direct thrombin inhibitors); co-administration of MMP-9 inhibitors to deter haemorrhagic transformation; and prehospital neuroprotection to support threatened tissues until reperfusion. Endovascular recanalisation strategies are rapidly evolving, and include intra-arterial fibrinolysis, mechanical clot retrieval, suction thrombectomy, and primary stenting. Combined approaches appear especially promising, using IV fibrinolysis to rapidly initiate reperfusion, mechanical endovascular treatment to debulk large, proximal thrombi, and intra-arterial (IA) fibrinolysis to clear residual distal thrombus elements and emboli.