Significance of aortic atheroma in elderly patients with ischemic stroke

Meta-Analysis of Secondary Prevention of Cryptogenic Stroke

BACKGROUND

Cryptogenic stroke and embolic stroke of undetermined source (ESUS) are a frequently encountered categories of ischemic stroke with an uncertain cause.

METHODS

We analyzed all randomized clinical trials (RCTs) that evaluated antithrombotic therapy and patent foramen ovale (PFO) closure in cryptogenic stroke and/or ESUS. We calculated aggregate hazard ratios (HRs) using direct and network meta-analysis. The primary outcome was recurrent ischemic stroke.

RESULTS

Ten RCTs with a total of 16,876 patients, randomizing 32,143 patient-years of follow-up (mean age 61.2 ± 13.5 with 39.2% female) were identified. Anticoagulation therapy was associated with significantly reduced recurrent ischemic stroke compared with antiplatelet therapy (HR = 0.66; [95% confidence interval (CI) = 0.47-0.94]). Meta-regression analysis showed significantly reduced recurrent stroke with longer duration of therapy, and significantly increased events with advanced age. Significant interactions were observed based on the presence of PFO, stroke type, and anticoagulant used. There were no significant differences with regard to the composite ischemic outcome, transient ischemic attack, any death, major bleeding, or intracranial bleeding. In the network meta-analysis, compared to antiplatelet therapy, warfarin (HR = 0.31; [95% credible interval (CrI) = 0.12-0.68]) and PFO closure (HR = 0.14; 95% CrI = 0.05-0.31]) were associated with significantly reduced recurrent ischemic stroke. In rank order, PFO closure was associated with the best outcome, followed by warfarin.

CONCLUSIONS

Among patients with cryptogenic stroke, anticoagulation therapy, as compared with antiplatelet therapy is associated with lower rate of recurrent stroke. The small sample size and high heterogeneity with regards to bleeding outcomes require further large trials. In patients with PFO, closure and warfarin are associated with the lowest rates of recurrent stroke.

Association Between Cystatin C and the Risk of Ischemic Stroke: a Systematic Review and Meta-analysis

Ischemic stroke is a disease that affects people^'s health and quality of life. Cystatin C has been found as a new biomarker of cardiovascular disease. We performed this meta-analysis to assess the relationship between cystatin C and the risk of ischemic stroke. The studies on looking at the association between cystatin C and ischemic stroke were identified from inception to November 18, 2018. We performed a random-effects meta-analysis using mean difference. Nine studies with a total of 3773 ischemic stroke patients were included into the meta-analysis. Our results showed that patients with ischemic stroke had significantly higher serum cystatin C concentrations compared with the participants without ischemic stroke (pooled mean difference, 0.11; 95% confidence interval (CI), 0.00-0.22; P = 0.04), in particular acute ischemic stroke and subclinical cerebral infarction (mean difference, 0.23; 95% CI, 0.11-0.36; P = 0.0003 and mean difference, 0.07; 95% CI, 0.05-0.09; P < 0.00001, respectively). Cystatin C was associated with ischemic stroke, and it could be considered a predictor for the risk of ischemic stroke, especially in acute ischemic stroke and subclinical cerebral infarction.

Detecting atheromatous plaques in the aortic arch or supra-aortic arteries for more accurate stroke subtype classification

INTRODUCTION

To investigate the correlations of atheromatous plaques in the aortic arch or supra-aortic arteries with intracranial arterial stenosis and carotid plaques in stroke patients, and to determine whether taking these plaques into account will reduce the proportion of patients in the undetermined etiology group.

METHODS

We prospectively enrolled 308 ischemic stroke patients, whose clinical characteristics and A-S-C-O classifications were compared with analyses of intracranial arteries, carotid arteries, aortic arch, and supra-aortic arteries.

RESULTS

125(40.6%) patients had plaques in the aortic arch or supra-aortic arteries, of which 106 (84.8%) had complex plaques. No correlations were observed between these plaques and carotid plaques ( p = 0.283) or intracranial arterial stenosis ( p = 0.097). After detecting the mobile thrombi in the aortic arch and supra-aortic arteries, the proportion of patients in the atherothrombosis group was increased from 33.8% to 55.5% ( p = 0.00), whereas the proportion of patients in stroke of undetermined etiology group was decreased from 19.2% to 11.0% ( p = 0.00).

DISCUSSION

Examining only the carotid and intracranial arteries may not provide adequate information about large arteries in stroke patients. Therefore, it would be better to include a search for relevant plaques in the aortic arch or supra-aortic arteries in modern stroke workup, for it may lead to more accurate stroke subtype classification and guide secondary prevention.

Embolic strokes of undetermined source: the case for a new clinical construct

Cryptogenic (of unknown cause) ischaemic strokes are now thought to comprise about 25% of all ischaemic strokes. Advances in imaging techniques and improved understanding of stroke pathophysiology have prompted a reassessment of cryptogenic stroke. There is persuasive evidence that most cryptogenic strokes are thromboembolic. The thrombus is thought to originate from any of several well established potential embolic sources, including minor-risk or covert cardiac sources, veins via paradoxical embolism, and non-occlusive atherosclerotic plaques in the aortic arch, cervical, or cerebral arteries. Accordingly, we propose that embolic strokes of undetermined source are a therapeutically relevant entity, which are defined as a non-lacunar brain infarct without proximal arterial stenosis or cardioembolic sources, with a clear indication for anticoagulation. Because emboli consist mainly of thrombus, anticoagulants are likely to reduce recurrent brain ischaemia more effectively than are antiplatelet drugs. Randomised trials testing direct-acting oral anticoagulants for secondary prevention of embolic strokes of undetermined source are warranted.

Correlation between aortic/carotid atherosclerotic plaques and cerebral infarction

The aim of this study was to investigate the correlation between aortic/carotid atherosclerotic plaques and cerebral infarction. We examined 116 cases of cerebral infarction using transcranial Doppler ultrasound in order to exclude cerebrovascular stenosis. Transesophageal echocardiography and color Doppler ultrasound were used to detect aortic atherosclerotic plaques (AAPs) and carotid atherosclerotic plaques (CAPs). AAPs were detected in a total of 70 of the 116 cases (60.3%), including 56 with moderate/severe atherosclerotic changes (48.3%). The difference in the incidence of various types of infarction between APP severity levels was significant (P<0.01). Of the 116 cases, 64 had CAPs (55.2%), including 46 with unstable plaque (39.7%). The difference in the incidence of various types of infarction between CAP stability levels was significant (P<0.01). The results indicate that moderate/severe AAP and unstable CAP are significant causes of embolic infarction without stenosis in the internal carotid arteries.

CT angiography of the aorta is superior to transesophageal echocardiography for determining stroke subtypes in patients with cryptogenic ischemic stroke

BACKGROUND

The etiology of ischemic strokes remains cryptogenic in about one third of patients, even after extensive workup in specialized centers. Atherosclerotic plaques in the aorta can cause thromboembolic events but are often overlooked. They can elude standard identification by transesophageal echocardiography (TEE), which is invasive or at best uncomfortable for many patients. CT angiography (CTA) can be used as an alternative or in addition to TEE if this technique fails to visualize every part of the aorta and in particular the aortic arch.

METHODS

We prospectively studied 64 patients (47 men, age 60 ± 13 years) classified as having cryptogenic stroke after standard and full workup [including brain MRI and 24-hour electrocardiogram (ECG)] with ECG-triggered CTA of the aorta in search of plaques and compared the results with those of TEE. Investigators were blinded to the results of both techniques. Plaques were graded on CTA according to their presence (0 = not present; 1 = mild; 2 = severe) and degree of calcification (1a or 2a = noncalcified; 1b or 2b = calcified). Associations with risk factors and infarct localization were also assessed.

RESULTS

Only 21 of 64 patients (32.8%) had aortic plaques identified by TEE, compared to 43 of 64 (67.2%) with CTA (p < 0.05). The plaque localization was as follows (TEE vs. CTA): ascending aorta, 10 vs. 20 (p < 0.05); aortic arch, 10 vs. 40 (p < 0.05), and descending aorta, 20 vs. 34 (p < 0.05). Grade 1 plaques were most commonly found in the aortic arch (25; 39%), while grade 2 plaques were most often detected in the aortic arch (15; 23.4%) and the descending aorta (14; 21.9%). There was no significant correlation between plaque location, infarct territory or vascular risk profile, except for hypertension (p = 0.003), which was significantly associated with the presence of plaques.

CONCLUSIONS

CTA identifies more plaques throughout the aortic arch and around the origins of the major cerebral arteries in particular compared to TEE. These may represent potential embolic sources of acute ischemic stroke. Better plaque detection may have an impact on the best available secondary prevention regimen in individual patients if proximal embolic sources are suspected.

Capillary injury in the ischemic brain of hyperlipidemic, apolipoprotein B-100 transgenic mice

AIMS

Apolipoprotein B-100 (apoB-100) has been implicated in hyperlipidemia, which contributes to the pathogenesis of vascular disorders. Our aim was to investigate whether the expression of human apoB-100 in transgenic mice and/or a high-cholesterol diet cause cerebral microvascular lesions, and whether these conditions augment ischemia-related capillary damage.

MAIN METHODS

Human apoB-100 overexpressing transgenic (Tg(apoB-100), n=23) and wild-type mice (C5/B6, Wt, n=26) were supplied with standard or 2% cholesterol-enriched diet for 17-19 weeks. Cerebral ischemia was induced by unilateral common carotid artery occlusion. Cortical samples were embedded for electron microscopy. Microvascular density (number of microvascular profiles/examined area), lumen diameter, the swelling of astrocytic endfeet, the occurrence of endothelial microvilli (affected capillaries expressed as ratio of all capillaries encountered), and the ratio of intact capillaries (devoid of all the above pathology) were calculated.

KEY FINDINGS

The expression of apoB-100 coincided with decreased cortical microvascular density (195+/-7 vs. 223+/-8 vessels/mm(2), vs. Wt; P<0.008) and increased capillary lumen diameter (3.16+/-0.5 vs. 2.88+/-0.6 microm, vs. Wt; P<0.001). Cerebral ischemia promoted the swelling of perivascular astrocytes (62.1+/-4.2 vs. 36.5+/-4.0%, vs. contralateral, Wt; P<0.001), and reduced the ratio of intact capillaries (32.1+/-5.6 vs. 65.2+/-3.7%, vs. contralateral, Wt; P<0.001). Hyperlipidemia did not exacerbate the injury.

SIGNIFICANCE

The overexpression of human apoB-100 alters the density of the microvascular network and the diameter of capillaries, which may compromise cerebrovascular reactivity during ischemia.

Use of carotid intima-media thickness to identify patients with ischemic stroke and transient ischemic attack with low yield of cardiovascular sources of embolus on transesophageal echocardiography

BACKGROUND AND PURPOSE

Carotid intima-media thickness (CIMT) is associated with systemic atherosclerosis and cardioembolic conditions and predicts the risk of recurrent strokes. We sought to establish the relationship between CIMT and cardiovascular sources of embolus (CSE) on transesophageal echocardiography (TEE) and hypothesized that a noninvasive strategy of CIMT assessment and transthoracic echocardiography bubble study would identify patients with ischemic stroke or transient ischemic attack in whom TEE would provide little incremental diagnostic yield.

METHODS

In 180 patients with ischemic stroke or transient ischemic attack of undetermined origin referred for TEE, we prospectively performed CIMT measurement/plaque screen (Phase 1, n=96) or CIMT measurement/plaque screen and transthoracic echocardiography bubble study (Phase 2, n=84) before TEE. Phase 1 results were used to construct receiver operating characteristic curves to demonstrate the ability of CIMT to detect CSE on TEE and to identify the optimal CIMT cutoff value for prospective strategy testing (Phase 2).

RESULTS

In Phase 1, CIMT was found to correlate with TEE markers of aortic atherosclerosis, including complex aortic plaques, and combined CSE. The optimal CIMT cutoff for detection of CSE on TEE was 0.78 mm. In Phase 2, a positive noninvasive strategy test (CIMT >or=0.78 mm, +carotid plaque, and/or a positive transthoracic echocardiography bubble study) was present in 61%. The prevalence of CSE on TEE was significantly higher among those with a positive compared with a negative noninvasive strategy test (65% versus 9%, P<0.001), and this strategy had a sensitivity of 92% and a negative predictive value of 91% for the detection of any CSE on TEE.

CONCLUSIONS

In patients with stroke or transient ischemic attack of undetermined origin, a noninvasive strategy of CIMT assessment/plaque screen and transthoracic echocardiography bubble study can identify patients in whom further invasive evaluation with TEE will be of low diagnostic yield.