Large Left Ventricular Pseudoaneurysm Presenting as an Embolic Stroke After a "Silent" Myocardial Infarction.

A 72-year-old woman with no history of coronary artery disease presented with an acute left middle cerebral artery stroke and was found to have a large left ventricular pseudoaneurysm measuring 8.7 × 7.6 cm and 2 large left ventricular thrombi, the source of her systemic embolization. Despite initial medical management, she developed refractory New York Heart Association functional class III heart failure, uncontrolled atrial fibrillation, and further enlargement of her pseudoaneurysm to 5.5 × 10.6 × 9.2 cm. She underwent urgent aneurysmectomy. Left ventricular pseudoaneurysms are rare and most commonly occur following an acute myocardial infarction when a ventricular free-wall rupture is contained by pericardium or thrombi. Historically, left ventricular angiography displaying a lack of an overlying coronary artery was the gold standard for diagnosis. Now, noninvasive imaging such as computed tomography, magnetic resonance imaging, and echocardiogram with ultrasound-enhancing agent, are reliable diagnostic tools. They can distinguish a pseudoaneurysm from a true left ventricular aneurysm using characteristic findings such as a narrow aneurysm neck, bidirectional doppler flow between the pseudoaneurysm and the left ventricle, and abrupt changes in the cardiac wall structures. Progressive dilation, wall thinning, and dyskinesis can result in refractory heart failure, arrhythmias, and thrombi formation from venous stasis. Pseudoaneurysms have a 30% to 45% risk of rupture and can be treated with left ventricular aneurysmectomy.

Acute Hyperglycemia Exacerbates Hemorrhagic Transformation after Embolic Stroke and Reperfusion with tPA: A Possible Role of TXNIP-NLRP3 Inflammasome.

OBJECTIVES: Acute hyperglycemia (HG) exacerbates reperfusion injury after stroke. Our recent studies showed that acute HG upregulates thioredoxin-interacting protein (TXNIP) expression, which in turn induces inflammation and neurovascular damage in a suture model of ischemic stroke. The aim of the present study was to investigate the effect of acute HG on TXNIP-associated neurovascular damage, in a more clinically relevant murine model of embolic stroke and intravenous tissue plasminogen activator (IV-tPA) reperfusion. MATERIALS AND METHODS: HG was induced in adult male mice, by intraperitoneal injection of 20% glucose. This was followed by embolic middle cerebral artery occlusion (eMCAO), with or without IV-tPA (10 mg/kg) given 3 h post embolization. Brain infarction, edema, hemoglobin content, expression of matrix metalloproteinase (MMP-9), vascular endothelial growth factor A (VEGFA), tight junction proteins (claudin-5, occluding, and zonula occludens-1), TXNIP, and NOD-like receptor protein3 (NLRP3)-inflammasome activation were evaluated at 24 h after eMCAO. RESULTS: HG alone significantly increased TXNIP in the brain after eMCAO, and this was associated with exacerbated hemorrhagic transformation (HT; as measured by hemoglobin content). IV-tPA in HG conditions showed a trend to decrease infarct volume, but worsened HT after eMCAO, suggesting that HG reduces the therapeutic efficacy of IV-tPA. Further, HG and tPA-reperfusion did not show significant differences in expression of MMP-9, VEGFA, junction proteins, and NLRP3 inflammasome activation between the groups. CONCLUSION: The current findings suggest a potential role for TXNIP in the occurrence of HT in hyperglycemic conditions following eMCAO. Further studies are needed to understand the precise role of vascular TXNIP on HG/tPA-induced neurovascular damage after stroke.

First approach to distinguish between cardiac and arteriosclerotic emboli of individual stroke patients applying the histological THROMBEX-classification rule.

Endovascular treatment of strokes caused by large vessel occlusion enables the histopathological investigation of the retrieved embolus, possibly providing a novel opportunity to contribute to the diagnostic workup of etiology and to define secondary prevention measures in strokes with uncertain genesis. We aimed to develop a classification rule based on pathophysiological considerations and adjustment to reference thrombi for distinction between cardiac and arteriosclerotic emboli and to validate this classification rule on a patient cohort. From 125 patients with stroke due to large vessel occlusion and thrombectomy, 82 patients with known etiology (55 cardioembolic and 27 arterioembolic strokes) were included. The corresponding emboli were histologically evaluated by two raters blinded to the etiology of stroke by means of a novel classification rule. Presumed etiology and classification results were compared. Agreement concerning cardiac emboli was 72.2% (95% CI: 58.4-83.5) for rater I and 78.2% (95% CI: 65.0-88.2) for rater II. Agreement concerning arteriosclerotic emboli was 70.4% (95% CI: 49.8-86.3) for rater I and 74.1% (95% CI: 53.7-88.9) for rater II. Overall agreement reached 71.6% (95% CI: 60.5-81.1) for rater I and 76.8% (95% CI: 66.2-85.4) for rater II. Within the limits of generally restricted accuracy of histological evaluations, the classification rule differentiates between cardiac and arteriosclerotic emboli of acute ischemic stroke patients. Further improvement is needed to provide valuable complementary data for stroke etiology workup.

Pinocembrin attenuates hemorrhagic transformation after delayed t-PA treatment in thromboembolic stroke rats by regulating endogenous metabolites.

Hemorrhagic transformation (HT) is a common serious complication of stroke after thrombolysis treatment, which limits the clinical use of tissue plasminogen activator (t-PA). Since early diagnosis and treatment for HT is important to improve the prognosis of stroke patients, it is urgent to discover the potential biomarkers and therapeutic drugs. Recent evidence shows that pinocembrin, a natural flavonoid compound, exerts anti-cerebral ischemia effect and expands the time window of t-PA. In this study, we investigated the effect of pinocembrin on t-PA-induced HT and the potential biomarkers for HT after t-PA thrombolysis, thereby improving the prognosis of stroke. Electrocoagulation-induced thrombotic focal ischemic rats received intravenous infusion of t-PA (10 mg/kg) 6 h after ischemia. Administration of pinocembrin (10 mg/kg, iv) prior t-PA infusion significantly decreased the infarct volume, ameliorated t-PA-induced HT, and protected blood-brain barrier. Metabolomics analysis revealed that 5 differential metabolites in the cerebral cortex and 16 differential metabolites in serum involved in amino acid metabolism and energy metabolism were significantly changed after t-PA thrombolysis, whereas pinocembrin administration exerted significant intervention effects on these metabolites. Linear regression analysis showed that lactic acid was highly correlated to the occurrence of HT. Further experiments confirmed that t-PA treatment significantly increased the content of lactic acid and the activity of lactate dehydrogenase in the cerebral cortex and serum, and the expression of monocarboxylate transporter 1 (MCT 1) in the cerebral cortex; pinocembrin reversed these changes, which was consistent with the result of metabolomics. These results demonstrate that pinocembrin attenuates HT after t-PA thrombolysis, which may be associated with the regulation of endogenous metabolites. Lactic acid may be a potential biomarker for HT prediction and treatment.

Atrial Cardiopathy and Likely Pathogenic Patent Foramen Ovale in Embolic Stroke of Undetermined Source.

BACKGROUND: Atrial cardiopathy and likely pathogenic patent foramen ovale (PFO) are two potential embolic sources in patients with embolic stroke of undetermined source (ESUS). The relationship between these two mechanisms among ESUS patients remains unclear. METHODS: Atrial cardiopathy was defined as increased left atrial diameter index (> 23 mm/m2) or left atrial volume index (> 34 mL/m2), or PR prolongation (≥ 200 ms), or presence of supraventricular extrasystoles in the electrocardiograms performed during hospitalization for the index stoke. The presence of PFO was assessed by transthoracic echocardiography with microbubble test or by transesophageal echocardiography. The presence of PFO was considered as likely pathogenic if the Risk of Paradoxical Embolism score was 7 to 10. RESULTS: Among 367 ESUS patients with available information about the presence of PFO and the presence of atrial cardiopathy (median age: 61 years, 40.6% women), likely pathogenic PFO was diagnosed in 62 (16.9%) and atrial cardiopathy in 122 (33.2%). Only 4 patients (1.1%) had both likely pathogenic PFO and atrial cardiopathy. The prevalence of atrial cardiopathy was lower in patients with likely pathogenic PFO (6.5%) compared with patients with likely incidental PFO (31.2%) or without PFO (40.6%) (Pearson's chi-square test: 26.08, p < 0.001; adjusted odds ratio [OR]: 0.28, 95% confidence interval [CI]: 0.09-0.86). The prevalence of likely pathogenic PFO was lower in patients with atrial cardiopathy compared with patients without atrial cardiopathy (3.3% vs. 23.7%, respectively [Pearson's chi-square test: 24.13, p < 0.001; adjusted OR: 0.2, 95% CI: 0.02-0.6]). CONCLUSION: The presence of atrial cardiopathy is inversely related to the presence of likely pathogenic PFO in patients with ESUS.

Fibrin and Platelet-Rich Composition in Retrieved Thrombi Hallmarks Stroke With Active Cancer.

BACKGROUND AND PURPOSE: We aim to investigate whether histopathologic examination of thrombi retrieved from acute ischemic stroke patients undergoing endovascular treatment could distinguish cancer-related stroke from other etiologies. METHODS: Thrombi from patients undergoing endovascular treatment were analyzed. The etiology of stroke was divided into cardioembolism, large artery atherosclerosis, and active cancer groups. All selected thrombi were subjected to hematoxylin and eosin staining. The percentages of fibrin/platelets, red blood cells, and white blood cells within a thrombus were quantified. RESULTS: One-hundred fifty-two patients (active cancer, 19; cardioembolism, 107; large artery atherosclerosis, 26) were included. Thrombi from the active cancer group exhibited a higher fibrin/platelet composition than did those from the cardioembolism and large artery atherosclerosis groups (median, 85.7% versus 43.9% and 42.5%; P<0.001). Fibrin/platelet composition was the only independent factor (odds ratio, 1.05 [95% CI, 1.02-1.08]) in differentiating cancer-related stroke from stroke caused by cardioembolism and large artery atherosclerosis. A fibrin/platelet proportion of ≥65% accurately predicted cancer-related stroke (area under the curve, 0.84; P<0.001). CONCLUSIONS: In thrombi retrieved from patients undergoing endovascular treatment, a high fibrin/platelet composition was a probable indicator of cancer-related stroke.

Clot composition of embolic strokes of undetermined source: a feasibility study.

BACKGROUND: A number of emerging studies have evaluated clot composition in acute ischemic stroke. Studies of clot composition of embolic strokes of undetermined strokes are lacking. OBJECTIVES: We sought to analyze the RBC to platelet ratios in clots and correlated our findings with stroke etiology. METHODS: This was a prospective study analyzing clots retrieved by mechanical thrombectomy in acute ischemic stroke patients at our institution. All clots were stained and scanned at 200x magnification by using a Scanscope XT digital scanner (Apergio, Vista, California). Image-J software (National Institutes of Health, Bethesda, Maryland) was used for semi quantitative analysis of percentage RBC's and platelets. Unpaired t-test was used to compare means of RBC to Platelet ratios. Correlation of RBC to Platelet ratios with stroke etiology was performed. RESULTS: A total of 33 clots from 33 patients were analyzed. Stroke etiology was undetermined in 6 patients, cardioembolic in 14, large vessel atherosclerosis (LVA) in 9, and carotid dissection in 4. The mean RBC to platelet ratio was 0.78:1 (+/- 0.65) in cardioembolic clots, 1.73:1 (+/- 2.38) in LVA and 1.4:1(+/- 0.70) in carotid dissections. Although patients with undetermined etiology had a similar clot composition to cardioembolic stroke (0.36:1+/- 0.33), (p = 0.19), it differed significantly from LVA and dissections respectively (p = 0.037, p = 0.01). CONCLUSION: In our study, a low RBC to Platelet ratio was found among patients with embolic strokes of undetermined source, however shared similar characteristics with cardioembolic thrombi. Ongoing collection and analysis is needed to confirm these findings and its significance in evaluating stroke etiology.

Quantitative Morphology of Cerebral Thrombi Related to Intravital Contraction and Clinical Features of Ischemic Stroke.

BACKGROUND AND PURPOSE: The purpose was to assess quantitatively and qualitatively the composition and structure of cerebral thrombi and correlate them with the signs of intravital clot contraction (retraction), as well as with etiology, severity, duration, and outcomes of acute ischemic stroke. METHODS: We quantified high-resolution scanning electron micrographs of 41 cerebral thrombi for their detailed cellular and noncellular composition and analyzed histological images for the overall structure with the emphasis on red blood cell compression, fibrin age, and the signs of inflammation. RESULTS: Cerebral thrombi were quite compact and had extremely low porosity. The prevailing cell type was polyhedral compressed erythrocytes (polyhedrocytes) in the core, and fibrin-platelet aggregates were concentrated at the periphery; both findings are indicative of intravital contraction of the thrombi. The content of polyhedrocytes directly correlated with the stroke severity. The prevalence of fibrin bundles was typical for more severe cases, while the content of fibrin sponge prevailed in cases with a more favorable course. The overall platelet content in cerebral thrombi was surprisingly small, while the higher content of platelet aggregates was a marker of stroke severity. Fibrillar types of fibrin prevailed in atherothrombogenic thrombi. Older fibrin prevailed in thrombi from the patients who received thrombolytics, and younger fibrin dominated in cardioembolic thrombi. Alternating layers of erythrocytes and fibrin mixed with platelets were common for thrombi from the patients with more favorable outcomes. Thrombi with a higher number of leukocytes were associated with fatal cases. CONCLUSIONS: Most cerebral thrombi undergo intravital clot contraction (retraction) that may be of underestimated clinical importance. Despite the high variability of the composition and structure of cerebral thrombi, the content of certain types of blood cells and fibrin structures combined with the morphological signs of intravital contraction correlate with the clinical course and outcomes of acute ischemic stroke.

An Autopsy Case of Lambl's Excrescences with Trousseau Syndrome that Caused Cardioembolic Stroke.

The frequency and risk of embolism by Lambl's excrescences (LEs) remain unclear. We herein report an autopsy case of LEs that caused cardioembolic stroke. A 74-year-old man with colon cancer was hospitalized for ischemic stroke. His D-dimer levels were elevated. Thus, a diagnosis of ischemic stroke with Trousseau syndrome was made. At the autopsy, we found LEs in the aortic valves and thromboembolism of the brain blood vessels. This finding demonstrated that fibrin clots had adhered to the LEs because of coagulation abnormalities associated with Trousseau syndrome and became embolized. This case highlights the risk of LEs in patients with coagulation abnormalities.

Selective intra-arterial brain cooling improves long-term outcomes in a non-human primate model of embolic stroke: Efficacy depending on reperfusion status.

Nearly all stroke neuroprotection modalities, including selective intra-arterial cooling (SI-AC), have failed to be translated from bench to bed side. Potentially overlooked reasons may be biological gaps, inadequate attention to reperfusion states and mismatched attention to neurological benefits. To advance stroke translation, we describe a novel thrombus-based stroke model in adult rhesus macaques. Intra-arterial thrombolysis with tissue plasminogen activator leads to three clinically relevant outcomes - complete, partial, and no recanalization based on digital subtraction angiography. We also find reperfusion as a prerequisite for SI-AC-induced benefits, in which models with complete or partial reperfusion exhibit significantly reduced infarct volumes, mitigated neurological deficits, improved upper limb motor dysfunction in both acute and chronic stages; however, no further neuroprotection is observed in those without reperfusion. In summary, we discover reperfusion as a crucial regulator of SI-AC-induced neuroprotection and provide insights of long-term functional benefits in behavior and imaging levels. Our findings could be important not only for the translational prerequisite and potential molecular targets, but also for this thrombus-thrombolysis model in monkeys as a powerful tool for further translational stroke studies.

Carotid web leads to new thrombus formation: computational fluid dynamic analysis coupled with histological evidence.

Carotid web has been recognized as a rare cause of ischemic stroke with high recurrence rate. We describe a 48-year-old woman with carotid web who developed embolic stroke. We obtained a fresh thrombus from the internal carotid artery when carotid endarterectomy was performed. A preoperative computational fluid dynamics (CFD) study showed stagnation of blood around the web structure as well as the low wall shear stress. The rheological analysis newly disclosed mechanisms of thrombus formation related to the carotid web. CFD study in the carotid web may determine indication and timing of surgical interventions with further accumulation of clinical evidence.