Red Thrombus Research Articles

Amine-modified nanoplastics promote the procoagulant activation of isolated human red blood cells and thrombus formation in rats

BackgroundMicroplastics (MPs) and nanoplastics (NPs) formed from decomposed plastic are increasing environmental threats. Although MPs and NPs exposed through various routes enter the systemic circulation, the potential toxicity of those is largely unknown. We investigated whether polystyrene NPs (PS-NPs) promote the coagulation activity of red blood cells (RBCs).ResultsWe tested several types of PS-NPs using human RBCs and found that amine-modified 100 nm PS-NPs were the most potent. We measured the uptake of PS-NPs using flow cytometry and confocal microscopy. Electron microscopy revealed morphological changes of RBCs by PS-NPs. PS-NPs induced the externalization of phosphatidylserine, generation of microvesicles in RBCs, and perturbations in the intracellular microenvironment. PS-NPs increased the activity of scramblases responsible for phospholipid translocation in RBCs. PS-NPs modulated the functional interaction to adjacent tissues and coagulation cascade, enhancing RBC adhesion and thrombin generation. Our observations in human RBCs were consistent with those in isolated rat RBCs, showing no inter-species differences. In rat venous thrombosis models, the intravenous administration of PS-NPs enhanced thrombus formation.ConclusionAmine-modified PS-NPs induce the prothrombotic activation of RBCs causing thrombus formation. We believe that our study will contribute to understanding the potential toxicity of amine-modified polystyrene particles in blood cells and cardiovascular systems.

Intracoronary thrombus visualized by optical coherence tomography in a patient with antiphospholipid syndrome

Abstract A patient with a history of deep venous thrombosis on warfarin underwent coronary angiography and was found to have a red intracoronary thrombus in the mid left anterior descending artery by optical coherence tomography. Percutaneous coronary intervention was successfully performed. On discharge, the patient continued triple therapy with aspirin, clopidogrel, and apixaban for 30 days then discontinued aspirin. A hypercoagulable work up was notable for antiphospholipid syndrome and lifelong anticoagulation was recommended. The patient continued apixaban twice daily given recurrent thrombosis while on warfarin and was event free at 6-month follow up.

P201 PURSUING COMPLETENESS OF CORONARY REVASCULARIZATION IN ACUTE SETTING: TIMING AND STRATEGIES

Abstract Patient Presentation A 59 y/o male with history of arterial hypertension and allergic asthma was admitted to our Coronary Care Unit because he went to a spoke emergency department after complaining oppressive and not continuous chest pain for a couple of hours travelling up to the left arm. Increase in cardiac troponin and mild ST–elevation in D3 lead were found. At the spoke cardiology department was treated with intravenous nitrates with relief and Ticagrelor loading dose was administered. He underwent two coronary angiographies, the first one aimed to treat the culprit lesion and the second one to complete revascularization before discharge Management: A heart ultrasound (US) described normal left ventricle ejection fraction (LVEF) with some of the right coronary segments akinesis. The first coronary angiography showed eccentric stenosis (80%) of distal right coronary artery (RCA) with endoluminal thrombosis; intraluminal filling defect of the left main coronary artery (LMCA) which request Optical Coherence Tomography evaluation that showed plaque rupture and red thrombus of LMCA; chronic total occlusion of left anterior descending artery (LAD) with several stenosis up to the apical segments. Glycoprotein IIb/IIIa receptor antagonist infusion was started, and we’ve been forced to treat first the LMCA with drug–eluting stent and then the culprit lesion with angioplasty and two drug–eluting stents complicated by intrastent thrombosis treated with mechanic and rheolytic thrombectomy. Seven days later rotational atherectomy was performed due to LAD artery’s severe calcifications complicated by LMCA intrastent thrombosis caused by stenting crush; cardiopulmonary arrest occurred. Impella ventricular assist device was placed. After LMCA stent optimization, one more drug–eluting stent was placed. Eight days later, heart US described LVEF 37% with apex and right coronary segments hypo–akinesis. Discussion According to latest NSTEMI guidelines, a single stage pursuing of completeness revascularization on multiple vessel disease would have been the best option. In this case, completeness of revascularization hasn’t been achievable due to LMCA plaque rupture. From a technical point of view, considering the complexity of the few days earlier treated LMCA lesion, proximal to LAD lesions we were going to treat, it would have been suitable waiting about four weeks to complete stent endothelization. By the way, it would have been out–guidelines approach.

Effect of Jingfang Granules on carrageenan-induced tail thrombosis in mice based on ERK/p38 MAPK signaling pathway

The present study explored the anti-inflammatory and anti-thrombotic mechanism of Jingfang Granules on tail thrombosis induced by carrageenan in mice. Thirty-two male ICR mice were randomly divided into a control group, a model group, a Jingfang Granules group, and a positive drug(aspirin) group, with eight mice in each group. The thrombosis model was induced by intraperitoneal injection of carrageenan(45 mg·kg~(-1)) combined with low-temperature stimulation, and the mice were treated with drugs for 7 days before modeling. Twenty-four hours after modeling, blood was detected for four blood coagulation indices in each group. The enzyme-linked immunosorbent assay(ELISA) was used to detect the activity of plasma interleukin-6(IL-6), interleukin-1β(IL-1β), tumor necrosis factor-α(TNF-α), and other inflammatory factors. The tails of mice in each group were cut off to observe tail lesions and measure the length of the thrombus. The protein expression and phosphorylation level of extracellular signal-regulated kinase 1/2(ERK1/2) and p38 mitogen-activated protein kinase(p38 MAPK) in spleen tissues were detected by Western blot. The results showed that dark red thrombus appeared in the tails of mice in each group. The length of the black part accounted for about 40% of the total tail in the model group. Additionally, the model group showed prolonged prothrombin time(PT), increased fibrinogen(FIB) content, and shortened activated partial thromboplastin time(APTT). Compared with the model group, the groups with drug intervention displayed shortened black parts in the tail and improved four blood coagulation indices(P<0.05). As revealed by ELISA, the expression levels of TNF-α, IL-1β, and IL-6 in the mouse plasma were significantly up-regulated in the model group, and those in the groups with drug intervention were reduced as compared with the model group(P<0.05). As demonstrated by Western blot, the protein expression and phosphorylation levels of ERK1/2 and p38 MAPK in the spleen tissues were significantly elevated in the model group, while those in the Jingfang Granules group were down-regulated as compared with the model group with a significant difference. Jingfang Granules can inhibit tail thrombosis of mice caused by carrageenan presumedly by inhibiting the activation of ERK1/2 and p38 MAPK signaling pathways.

Intracoronary thrombus assessment with cardiac computed tomography angiography in a deferred stenting strategy

Abstract Funding Acknowledgements Type of funding sources: None. Background. Cardiac computed tomography angiography (CCTA) is precise in non-invasive coronary atherosclerosis characterization but its value in the diagnosis of intracoronary thrombus remains unknown. Therefore, our aim was to evaluate the diagnostic accuracy of CCTA for intracoronary thrombus and stenosis detection in acute coronary syndromes (ACS) with high thrombus burden selected for a deferred stenting (DS) strategy. Methods. We systematically performed a CCTA in consecutive DS patients 24 hours before the scheduled repeated coronary angiography that also included optical coherence tomography (OCT) imaging. Intracoronary thrombus and residual stenosis were blindly and independently evaluated by both non-invasive and invasive diagnostic tests. Agreement was determined per lesion using weighted Kappa (K) coefficient and absolute intra-class correlation coefficient (ICC). A stratified analysis according to OCT-detected thrombus burden was also performed. Results. Thirty lesions in 28 consecutive patients with a large thrombus burden were analyzed. Concordance between CCTA and repeated coronary angiography in thrombus detection was good (K= 0.554; p< 0.001), but both showed a poor agreement with OCT. CCTA needed >11.5% thrombus burden on OCT to obtain adequate diagnostic accuracy. The lesions detected by angiography were more frequently classified as red thrombus (76.5 vs 33.3%; p= 0.087) on OCT. CCTA showed an excellent concordance with coronary angiography in diameter stenosis (ICC= 0.85; p< 0.001), and was able to identify all the patients with severe residual stenosis. Conclusion. CCTA is able to assess intracoronary thrombus. Although CCTA showed just a good concordance with angiography in thrombus detection, the agreement in residual stenosis was excellent. Thus, in patients with a high-thrombus burden CCTA may substitute repeat angiography in patients considered for DS. Abstract Figure.

736 Hazy spots: through the eye of optical coherence tomography

Abstract Aims Acute stent thrombosis after coronary artery stent placement is a rare but serious complication in percutaneous coronary intervention (PCI). Stenting culprit lesions in acute coronary syndrome (ACS) has higher risk of acute stent thrombosis than stable coronary artery disease, and many local and systemic factors may contribute to increase this risk. Tissue protrusion (TP), and in particular, plaque prolapse after PCI can play a role in acute stent thrombosis, and intra-vessel imaging is the principal instrument to identify such underlying lumen alteration after stent implantation, and guide intervention. Methods and results We report the case of a 54-year-old man with a history of hypertension, dyslipidemia, type 2 diabetes mellitus, obesity and no other relevant comorbidities in remote history, who underwent a coronary angiography for an unstable angina. A long, calcific sub-occlusion of the left anterior descending artery (LAD), which involved LAD-first diagonal branch (D1) bifurcation (Medina 1.1.1) and LAD-D2 bifurcation (Medina 1.1.0) was found. After deployment of two overlapping drug-eluting stents (DES), (ULTIMASTER TANSEI 3.0 × 38 mm and 3.0 × 21 mm) and struts apposition optimization with sequence of proximal optimization technique (POT) on D1 and D2, and a kissing balloon technique (KS) on LAD-D2 bifurcation, a ‘hazy’ in-stent image was detected right after the LAD-D2 bifurcation, suggesting an acute in-stent thrombosis, in absence of flow alteration (TIMI 3), symptoms or ECG modifications. Multiple thrombus-aspiration were made and resulted in abundant thrombus removal and improvement in the angiographic image, with persistent valid flow on every three vessels (TIMI 3). After 5 days of triple anticoagulant therapy with ticagrelor, cardioaspirin and UFH infusion, he underwent a new coronary angiography control. A similar ‘hazy’ image was detected right after LAD-D2 bifurcation within the LAD. An optical coherence tomography (OCT) pullback was made to assess the nature of the angiographic finding. OCT showed good struts apposition in almost every cross-sectional images, but an evident TP was detected right on the angiographic hazy spot. OCT allowed to evaluate the lipid-richness of the stented plaque and the nature of the TP, which was mixed with evident both white and red thrombus apposition (minimum luminal area measured 4.5 mm2). OCT guided a new PCI, with a stent-in-stent implantation on LAD. TP was absent on the post-PCI OCT run. Conclusions In this report, we showed the usefulness of OCT in revealing a potential high risk thrombogenic source. OCT not only characterized something that angiography alone couldn’t, but suggested the etiology of the amount of thrombus removed by the vessel during the first PCI. Indeed, despite an optimized cycle of anticoagulant therapy, OCT still revealed several mixed thrombus apposition on the TP, and this suggested its role in the acute stent thrombosis. OCT guided the choice to appose a new stent-in-stent to solve a potential thrombogenic source.

Plaque characteristics in patients with ST-segment elevation myocardial infarction and early spontaneous reperfusion.

Early spontaneous reperfusion (ESR) is not an uncommon phenomenon in clinical settings. The aim of this study was to detect potential mechanisms of ESR in patients with STEMI. This prospective study enrolled a total of 241 consecutive patients with STEMI undergoing optical coherence tomography (OCT) from July 2016 to August 2019. Forty-five patients (18.7%) met angiographic ESR criteria (TIMI 3 flow on the initial angiogram). Among those without ESR (TIMI 0 flow on initial angiogram), 45 patients were assigned to the control group according to propensity score matching with the ESR group. Although the baseline characteristics of the groups were comparable, non-ruptured plaque (62.2% vs 35.6%) predominated and plaque rupture (37.8% vs 64.4%) was less common in the ESR group (p=0.011). Red thrombus (44.4% vs 77.8%) was also less common in the ESR group (p=0.001). Lastly, compared to the control group, the ESR group underwent fewer emergent stent placements (68.9% vs 91.1%, p=0.008). Relief of coronary occlusion induced by a non-ruptured plaque may contribute to ESR in patients with STEMI.

Intracoronary Thrombogenicity in Patients with Vasospastic Angina: An Observation Using Coronary Angioscopy.

Background: Despite significant interest in intracoronary thrombi in patients with vasospastic angina (VSA), the phenomenon remains unclarified. Therefore, we investigated a possible relationship using coronary angioscopy (CAS) in VSA patients. Methods: Sixty patients with VSA, for whom we could assess the spastic segment using CAS, were retrospectively studied. An intracoronary thrombus on CAS was a white thrombus and an erosion-like red thrombus. We verified the clinical characteristics and lesional characteristics as they determined the risk of intracoronary thrombus formation. Results: There were 18 (30%) patients with intracoronary thrombi. More of the patients with intracoronary thrombi were male, current smokers and had severe concomitant symptoms; however, no statistically significant difference was observed upon logistic regression analysis. There were 18 (26%) coronary arteries with intracoronary thrombi out of 70 coronary arteries recognised in the spastic segments. Furthermore, atherosclerotic changes and segmental spasms were significant factors responsible for such lesions. Conclusion: Intracoronary thrombi occurred in 30% of VSA patients and much attention should be paid to the intracoronary thrombogenicity of VSA patients.

Laser Vaporization of Intracoronary Thrombus and Identifying Plaque Morphology in ST-Segment Elevation Myocardial Infarction as Assessed by Optical Coherence Tomography.

Objectives We evaluated the thrombus-vaporizing effect of excimer laser coronary angioplasty (ELCA) in patients with ST-segment elevation myocardial infarction (STEMI) by optical coherence tomography (OCT). Background Larger intracoronary thrombus elevates the risk of interventional treatment and mortality in patients with STEMI. Methods A total of 92 patients with STEMI who presented within 24 hours from the onset and underwent ELCA following manual aspiration thrombectomy (MT) were analyzed. Results The mean baseline thrombolysis in myocardial infarction flow grade was 0.4 ± 0.6, which subsequently improved to 2.3 ± 0.7 after MT (p < 0.0001) and 2.7 ± 0.5 after ELCA (p=0.0001). The median residual thrombus volume after MT was 65.7 mm3, which significantly reduced to 47.5 mm3 after ELCA (p < 0.0001). Plaque rupture was identified by OCT in only 22 cases (23.9%) after MT, but was distinguishable in 36 additional cases after ELCA (total: 58 cases; 63.0%). Ruptured lesions contained a higher proportion of red thrombus than nonruptured lesions (75.9% vs. 43.3%, p=0.001). Significantly larger thrombus burden after MT (69.6 mm3 vs. 56.3 mm3, p < 0.05) and greater thrombus reduction by ELCA (21.2 mm3 vs. 11.8 mm3, p < 0.01) were observed in ruptured lesions than nonruptured lesions. Conclusions ELCA effectively vaporized intracoronary thrombus in patients with STEMI even after MT. Lesions with plaque rupture contained larger thrombus burden that was frequently characterized by red thrombus and more effectively reduced by ELCA.

Platelet Cyclophilin D-Dependent Events Limit Venous Thrombotic Occlusion and Platelet Accretion

The role of platelets in arterial thrombosis is well established. Recent findings have reinforced their importance in venous thrombosis as well. Which of the platelet's many functions mediate its effects in the venous setting remains unclear, and how procoagulant platelet formation regulates venous thrombosis has not been investigated. Cyclophilin D (CypD) is a mitochondrial peptidylprolylisomerase that has the key function of regulation of mitochondrial permeability transition pore (mPTP) formation. In the absence of CypD, mPTP and procoagulant platelet formation are markedly impaired in response to physiologic agonists. The functional consequence of CypD's absence in vivo has been examined in photochemical injury models in photochemical injury models of both the carotid and mesenteric arteries. In mice with platelet CypD-deficiency, in both of these high shear settings, thrombotic vasoocclusion was accelerated implicating procoagulant platelet fragility and loss of adhesiveness as a critical factor limiting thrombus growth. Whether CypD deficiency would similarly impact thrombus growth in a venous setting has not been previously examined.To investigate the role of CypD and procoagulant platelets in the low shear setting of venous thrombosis, we utilized the inferior vena cava (IVC) stenosis ligature murine model of deep vein thrombosis (DVT). This model was chosen as it utilizes mechanical narrowing to induce thrombosis in the setting of venous flow. 24 hours following IVC ligation, thrombi were significantly larger (1.83 fold) in CypD-deficient mice than wild type. (p<0.05). Similarly, in mice with platelet-specific CypD-deficiency, thrombi were 1.54 fold larger than those found in WT mice (p<0.05). To begin to investigate the mechanism by which CypD-deficiency resulted in increased thrombus size, the composition of the venous thrombi was analyzed. Western blots for markers of platelets (CD41), neutrophils (Ly6G), and fibrin (59D8) revealed that their relative levels in thrombi were unchanged, but indicated that red blood cell (spectrin α1) accumulation increased. Histologic appearance in both CypD-deficient and wild-type thrombi was similar with a consistent pattern observed. A white cap area dominated the thrombus closest to the site of ligation, while red thrombus was more common in the remaining thrombus area. To investigate whether the observed pattern is due to more rapid occlusion, ultrasound was utilized to investigate the time course of venous vasoocclusion following ligature placement. Preliminary ultrasound studies suggest that CypD-deficient mice develop vasoocclusion more rapidly, perhaps thus accounting for their larger size.Previous studies have delineated the role of CypD-dependent events in limiting platelet accretion in vitro in arterial, but not venous, flow conditions. In vitro studies utilizing whole blood from CypD-deficient mice showed increased accretion of platelets on collagen under venous flow conditions. Similarly, platelet accretion increased when human whole blood was treated with cyclosporin A, an inhibitor of CypD, and flowed over collagen at venous rates. Interestingly, washed platelets from CypD-deficient mice also showed increased accumulation on a von Willebrand factor (VWF) - coated surface under venous flow conditions, a condition in which neither collagen nor coagulation-mediated procoagulant platelet formation would be expected to occur. Thus, these studies have identified an important role for CypD-dependent platelet events in the regulation of platelet accumulation in vitro and thus slowing the early stages of thrombus growth in vivo . The results here, in venous settings, and previously in arterial settings are consistent with a limiting role for procoagulant platelet formation in thrombus growth. This regulatory feedback role should be taken into consideration prior to modulation of procoagulant platelet formation in the setting of thrombosis or inflammation. DisclosuresNo relevant conflicts of interest to declare.

Exome Sequencing Studies Identify Mutations in STAB2 As a Genetic Risk for Venous Thromboembolic Disease

Deep vein thrombosis and pulmonary embolism, collectively referred to as venous thromboembolism (VTE), are the third leading cause of cardiovascular death in the United States. Genetic factors account for 50-60% of VTE risk and a recent meta-analysis of genome-wide association studies confirmed that common variants in F5, ABO, F2 and seven other very low effect size loci are associated with VTE. Rare mutations in the anticoagulant genes PROC (protein C), PROS1 (protein S) and SERPINC1 (antithrombin III) have been linked to highly penetrant VTE risk in family studies but no genome-wide study of rare variants has been reported to date.We performed whole exome sequencing (WES) in 373 unrelated individuals of European ancestry with well characterized unprovoked VTE and compared results to a previously genome sequenced control cohort of 5784 unrelated Europeans. We then identified single nucleotide variants, small insertion or deletions that were present at allele frequencies less than 0.005% in ExAC and had equal sequencing coverage between groups. Using a dominant model and a collapsing association analysis, we looked for genes that were more likely to harbor “knockout” (frame shift, nonsense, splice site and damaging missense) mutations in cases versus controls. Strikingly, ranked by p-value, among 17,395 genes tested, the top 4 genes were PROS1 (P= 2.01E-09, odds ratio: 11.8), STAB2 (P=2.70E-7, odds ratio 3.37), PROC (P=3.24E-05, odds ratio 11.0) and SERPINC1 (P=1.10E-04, odds ratio 8.5), Figure. These findings suggest that heterozygous deficiency for the STAB2 encoded protein, stabilin-2, confers VTE susceptibility similar to the previously well described phenotypes of heterozygous protein C, protein S and antithrombin III deficiency.Stabilin-2 is a single transmembrane glycoprotein scavenger receptor expressed on venous endothelium of liver sinusoids and spleen. We detected damaging STAB2 mutations in 29 (7%) VTE cases versus 141 (2%) of controls. Common and uncommon variants in STAB2 have been associated with elevated plasma von Willebrand factor (VWF) and coagulation factor VIII levels, which are known risk factors for VTE. Stabilin-2 is implicated as a clearance receptor for VWF, so that haploinsufficiency of stabilin-2 may increase plasma VWF half-life. To test this hypothesis, we examined 1162 individuals in the Twins UK Study (VTE status unknown) with available whole genome sequencing data and measured their plasma VWF levels by AlphaLISA. VWF levels were adjusted by log transformation and ABO blood type tagging SNPs. We identified 38 individuals (3.2%, all heterozygous) with rare damaging variants in STAB2. VWF levels were significantly higher in individuals (N=30) with rare STAB2 variants compared to those without (N=1016) (Mann-Whitney, P= 0.0046).To further examine stabilin-2 function in vivo, we compared Stab2 deficient mice (Stab2 -/-) to wild type (Stab2 +/+) controls. Stab2 -/- mice had elevated plasma levels of factor VIII:C (118%, p=0.0006), but no differences in VWF (p=0.58). Next, we examined thrombosis in a mouse model where venous blood clotting was induced by inferior vena cava stenosis. Thrombi were weighed and longitudinal sections were analyzed by quantitative immunohistochemistry 24 hours post-stenosis. Stab2 -/- mice developed significantly larger thrombi than Stab2 +/+ mice (194%, n=19, p=0.003) but no difference in DVT incidence (64% vs 61%, P= 0.85). Despite equivalent hematocrit (P= 0.91) and white type thrombus (P> 0.05), thrombi from Stab2 -/- mice were comprised of more red type thrombus (185%, P= 0.004).Through an unbiased analysis of whole exome sequencing in 6,157 individuals, this studyconfirms the role of haploinsufficiency of PROC, PROS1 and SERPINC1 for VTE susceptibility and identifies STAB2 deficiency as a potential new risk factor. Analysis of an independent human cohort of 1162 Europeans demonstrates that STAB2 haploinsufficiency is associated with elevated VWF levels, a known risk factor for VTE. Finally, a mouse model of Stab2 deficiency demonstrates enhanced thrombosis, though without an association with elevated VWF levels. Taken together, these results suggest that rare genetic variants in STAB2 collectively play a role in individuals with unprovoked VTE by prolonging the plasma half-life of procoagulant factors such as VWF, adding an important new gene to the short list of known risk factors for this common disease. [Display omitted] DisclosuresReitsma:Leiden University Medical Center; VarmX B.V.: Equity Ownership, Patents & Royalties: co-inventor on a patent application related to this abstract.

MO1030THE FIRST CASE OF ATYPICAL HEMOLYTIC UREMIC SYNDROME (AHUS) FEATURES IN AN EXPERIMENTAL MODEL

Abstract Background and Aims Thrombotic Microangiopathies (TM) are three distinct clinical syndromes presenting the same histological renal pattern: typical and atypical Hemolytic Uremic Syndrome (SEU- aSEU) and Thrombotic Thrombocytopenic Purpura (TTP). So far, the first report of a TM has been generally attributed to Eli Moschowitz. In 1922 he described the case of a 16 years old girl who died after acute onset of fever with petechial lesions and autoptic findings of hyaline thrombosis of terminal arterioles and capillaries, thus profiling the first case of TTP. Only in the 1955, Conrad Gasser described the first medical record of HUS, describing the case of a patient with a manifestation of bilateral necrosis of the renal cortex. We describe the first reported case of a Thrombotic Microangiopathy, in particular an experimentally induced aHUS by Richard M. Pearce in 1909. In this case, the trigger leading to aHUS was represented by snake venom injection in an experimental rabbit model. Method Pearce described acute glomerular lesions produced in the rabbit using dried venom of rattlesnake Crotalus Adamanteus. It was dissolved in salt solution in the proportion of 0.25 of a milligram to one cubic centimeter, rising gradually to two milligrams, and then followed by doses of 0.5 of a milligram of fresh venom at various intervals. The intervals between injections depended on the general condition of the animal and the amount of albuminuria. Results Rabbit kidneys showed well marked hemorrhagic and exudative lesions in the glomeruli; hyaline, granular, blood, and hemoglobin casts in both convoluted and collecting tubules; and granular degeneration of the epithelium of the convoluted tubules and loops of Henle. Pearce also described a “penetration of the cells of the compressed glomerular tuft into the mass of hemorrhage lying either in the tuft itself or in the capsular space” (Figure 1). In animals surviving 20-30 days after the first injection of the venom, the acute lesions were demonstrated to subside at the microscopic examination and their earlier presence was marked by “occasional casts and compressed masses of red cells in the glomerular spaces and tufts”. At the same time other models also showed “extensive granular degeneration of the convoluted tubules and many casts”. The renal autoptic findings presented the features of a vascular nephritis with severe endothelial changes. Conclusion Glomerular and tubular lesions of rabbits’ kidneys induced by crotalus’s venom showed typical features of what is today defined as aHUS. In this first experiment, the author described a glomerular tuft as “more analogous to the organization of a red thrombus than it is to any form of glomerular lesion known in man”, so we can affirm that Pearce described, ante litteram TMA histological features many years before other scientists.

Optical Coherence Tomography of Plaque Erosion and Thrombus in Severe Vertebral Artery Stenosis.

A 69-year-old male presented with medically refractory vertebrobasilar insufficiency and paroxysmal subjective dizziness for six months. Severe stenosis of a dominant left V2 vertebral artery segment was identified on digital subtraction angiography (DSA) with an irregular intraluminal filling defect immediately above the stenosis. Optical coherence tomography (OCT) demonstrated a normal lumen at the distal end, with red thrombus detected distal to the stenosis. Atherosclerotic plaque containing fibro-lipid was also identified and treated with a drug-eluting stent. Distal red thrombi were not covered by stenting, indicating embolization risk in the future. Clear posterior fossa symptoms occurred after intervention, and treatment with a standard dual antiplatelet regimen and statin therapy was prescribed for one year. Six months after treatment, the symptoms improved, and six-minute walking distances were successful with no gait impairment. To our knowledge, this is the first V2 segment stenosis assessed by OCT imaging before and after stenting, indicating an intact fibrous cap with thrombus formation, as well as plaque erosion. Understanding the role and careful use of OCT may improve the identification of red thrombus and plaque erosion when clinically indicated.

Association between Red Cell Distribution Width and Left Atrial Thrombus in Patients with Valvular Atrial Fibrillation

Background: Red cell distribution width (RDW) is a quantitative measure of variability in the size of circulating erythrocytes and previously shown to provide information concerning the prothrombotic status or adverse outcome of cardiovascular disease. Left atrial thrombus (LAT) is commonly detected in patients with valvular atrial fibrillation (VAF) due to rheumatic mitral valve stenosis (RMVS) but there is very limited data regarding the predictive value of RDW for the development of LAT in these patients.&#x0D; Aim: To determine the association between RDW and LAT in VAF patients.&#x0D; Methods: A total of 58 patients were included in a retrospective observational study between January 2016 to December 2016 in patients who admitted to Dr. Moewardi General Hospital, due to symptomatic VAF. Blood examination and transthoracic echocardiography were performed to all patients. LAT was defined as a fixed or mobile echogenic mass within left atrium (LA) and left atrial appendage (LAA). The RDW was compared between a patient with LAT or without LAT.&#x0D; Results: There were 28 patients (mean age: 46.2±13.3 years) in LAT(+) group and 30 patients (mean age: 45.6±11.5 years) in LAT(-) group. RDW was significantly higher in LAT(+) group (14.4±1.8% vs. 13.3±1.5%, p=0.010). The RDW was independent predictor of LAT by multivariate analysis (OR 1.619; p=0.020; 95% CI: 1.079-2.429). The cut-off RDW value for LAT was &gt;13.5% with a sensitivity of 73.3% and a specificity of 64.3% (area under curve=0.700; 95% CI: 0.562-0.838; p=0.009). The prevalence of LAT was significantly higher in patient with an RDW &gt;13.5% than in those with an RDW &lt;13.5 % (64.3% and 35.7%, p=0.002), with prevalence ratio 5.91.&#x0D; Conclusion: This study shows that a higher level of RDW has an association with the presence of LAT and an independent risk factor of LAT formation in patients with VAF.

Experimental Evaluation of the Risk of Distal Embolization during Endovascular Clot Retrieval Using Various Techniques.

Background:This study was conducted to evaluate various devices and techniques for endovascular thrombectomy that can reduce the risk of intraprocedural distal embolism in a preliminary in vitro setting with different types of thrombi.Materials and Methods:Endovascular clot retrieval was performed in a vascular model with collateral circulation. White and red thrombi were prepared using whole blood collected from a pig. A Direct Aspiration First Pass Technique (ADAPT), simple stentretrieving with and without proximal flow arrest by a guiding balloon (SR [B+] and SR [B±]), the AspirationRetriever Technique for Stroke (ARTS), and A stentretrieving into an Aspiration catheter with Proximal balloon (ASAP) were performed three times, respectively. The saline samples that were collected at the distal side during each procedure were examined using a particle counter. The particles were counted and categorized into three groups based on size (100 μm).Results:SR (B−) and SR (B+) could not achieve complete retrieval of the clot, especially using the white thrombus. ASAP was the only method that was able to retrieve the clots in all attempts. In both clot types, SR (B−), SR (B+), and ARTS, which involved a temporary flow restoration through stent deployment, demonstrated the migration of a greater number of particles measuring >100 μm in size than that shown by ADAPT and ASAP.Conclusions:ASAP was the safest method in terms of intraprocedural clot migration among the five methods evaluated in this study. Temporary flow restoration through stent deployment may affect the dangerous distal clot migration.

Morphology and phenotype characteristics of atherosclerotic plaque in patients with acute coronary syndrome: contemporary optical coherence tomography findings.

Contemporary optical coherence tomography (OCT) findings in patients with acute coronary syndromes (ACS) are still subject of controversy. We sought to use OCT to evaluate plaque morphology and phenotype classification in patients with ACS. Using optical coherence tomography, culprit lesions were morphologically classified as plaque rupture, plaque erosion, calcified nodule, thin-cap fibroatheroma, thick-cap fibroatheroma (TCFA) or fibrotic, fibrocalcific or fibrolipidic plaque. Quantitative and qualitative analyses also included cholesterol crystals, neovascularization, spotty calcification and thrombus. Of the 110 lesions imaged from June 2012 to April 2016, 54 (49%) were in patients with unstable angina (UA), 31 (28%) were in non-ST-elevation myocardial infarction (STEMI) patients and 25 (23%) were in STEMI patients. Compared with STEMI patients, patients with UA/non-STEMI were older and had more hypertension, hypercholesterolemia, known coronary artery disease, prior myocardial infarction and higher use of antiplatelet therapy. More patients with STEMI had lipidic arc >90% (36.6 versus 70.8%, P = 0.003), red and mixed thrombus (12.9 versus 28.0% and 7.1 versus 44.0%, respectively, all P < 0.001), plaque rupture (29.4 versus 76.0%, P < 0.001) and TCFA (57.1 versus 84.0%; P = 0.01). Predictors of plaque rupture were STEMI at presentation (odds ratio: 9.35, 95% confidence interval: 1.66-52.61, P = 0.01) and diabetes mellitus (odds ratio: 6.16, 95% confidence interval: 1.33-28.58, P = 0.02). In this single-center study, the culprit lesion of patients with STEMI had more lipid, red and mixed thrombus, plaque rupture and TCFA versus patients with UA/non-STEMI. Clinical presentation may be driven by distinct pathophysiologic mechanisms in patients with ACS.

Bifurcation Stenting Using Bioresorbable Vascular Scaffold in an Adult Male With Radiation-Induced Coronary Artery Disease and Hodgkin Lymphoma: A Case Report

INTRODUCTION: Radiation-induced coronary artery disease is associated with absolute risk between 0.1% and 0.5% per year after mediastinal radiotherapy of Hodgkin disease. Risk increases with time and becomes statistically significant after 10 years. This often involves the left anterior descending (LAD) and right coronary arteries with proximal arterial narrowing involving the coronary ostia. This is the first documented case of radiation-induced coronary artery disease in a 25-year-old Filipino man diagnosed with nodular sclerosing-type Hodgkin lymphoma stage IIA treated with percutaneous revascularization using bioresorbable vascular scaffolds in a bifurcation type of lesion admitted at St Luke’s Medical Center for chest pain. Patient reported progressive worsening of exertional angina 16 months after chemotherapy and external beam radiation therapy in the neck and mediastinum. Treadmill exercise test revealed inducible ischemia in the inferior leads at stage 3, 7 metabolic equivalents. Coronary angiogram showed severe stenosis involving the midsegment of the proximal LAD artery and the ostial-to-proximal segment of the first diagonal branch, a bifurcation lesion, Medina 1,1,1. A percutaneous coronary intervention was successfully done using two bioresorbable vascular scaffolds via T-and-protrude bifurcation stenting technique and achieves a brisk TIMI (Thrombolysis In Myocardial Infarction) 3 flow. Follow-up after 6 months showed a normal treadmill exercise test. However, patient still complains of occasional chest pain and epigastric discomfort. Coronary angiogram was repeated demonstrating an 80% stenosis in the proximal LAD without evidence of in-stent stenosis. This was confirmed by optical coherence tomography with adequate stent apposition to the intima with a note of a large chronic red thrombus proximal to the previously deployed stent; thus, percutaneous coronary intervention using drug-eluting stent was performed. KEYWORDS: radiation-induced coronary artery disease, Hodgkin lymphoma, bifurcation stenting, bioresorbable vascular scaffold, optical coherence tomography

Red and White Thrombus Characteristics in Patients Undergoing Carotid Endarterectomy

ObjectiveThe study aimed to compare the characteristics of red and white thrombi in patients undergoing carotid endarterectomy. Material and MethodsThe study was conducted in 81 patients with ischemic stroke who underwent carotid endarterectomy for carotid artery stenosis. Carotid plaques were graded by two pathologists. Thrombus materials were divided into two groups: white and red. The parameters of assessment were plaque rupture, lipid core, fibrous cap thickness, inflammation, intraplaque hemorrhage, calcification, necrotic core, and neovascularization. Normally distributed data were evaluated using Mann–Whitney U and Chi-squared tests. ResultsThe ratio of white and red thrombus was 19.8% and 80.2%, respectively. Lipid core, plaque rupture, necrotic core, neovascularization, intraplaque hemorrhage, obstruction, and inflammation were observed more in red thrombus, which were statistically significant. Calcification and fibrous cap thickness were not statistically significant in the two groups. Moreover, intimal smooth muscle cells were present in all thrombus types. ConclusionIn our study, we found that red thrombi had more unstable characteristics than white thrombi. Thus, the risk for ischemic cerebrovascular events is more in red thrombi. However, this finding cannot be generalized due to the small number of patients in this study. Therefore, studies involving more patients are needed.

Prognosis of acute ST-elevation myocardial infarction depending on the morphological features of intracoronary thrombi

Risk stratification among patients with acute ST-segment elevation myocardial infarction (STEMI) is very important. Morphological features of intracoronary thrombus significantly influence the prognosis.Aim. To estimate the prognosis after STEMI treated with primary percutaneous coronary intervention (PCI) depending on the morphological structure of intracoronary thrombi obtained during manual thromboaspiration.Materials and methods. Totally 97 patients with STEMI who underwent primary PCI were included into the study. Morphological structure of intracoronary thrombi obtained by manual thromboaspiration was evaluated in all participants. Further, the different structure of thrombi influence on the risk of developing a composite endpoint was determined, which represented a death, myocardial infarction, revascularization, and angina symptoms onset or worsening. The duration of follow-up was 24 months.Results. In 24 months after primary PCI, the occurrence of the endpoint correlated significantly only with macroscopic signs of intracoronary clots, negatively – with white (r = -0.21, P = 0.05) and red thrombi (r = -0.30, P &lt; 0.01), and positively – with mixed thrombi (r = 0.41, P &lt; 0.001). Using the logistic regression, the factors were revealed which in a case of combined action, may increase the risk of the combined endpoint: old blood clots (V1), the presence of microchannels (V2), peripheral leukocyte infiltration (V3), and gross mixed thrombi (V4). The following model was developed for calculating the probability of these factors influence on the occurrence of cardiovascular events included into the endpoint:Z = 2.37 × V1 + 2.21 × V2 + 1.69 × V3 + 3.24 × V4 - 5.60.The model is reliable (P &lt; 0.0001) with a sensitivity of 83.33 % and a specificity of 88.24 %.Conclusions. Despite the similar clinical manifestations and duration of the disease, intracoronary thrombi that cause STEMI differ significantly. Their morphological characteristics were related to the prognosis. These characteristics may be used for construction of a reliable risk scale that is suitable for clinical practice.

Concentrated Growth Factor Matrices Prepared Using Silica-Coated Plastic Tubes Are Distinguishable From Those Prepared Using Glass Tubes in Platelet Distribution: Application of a Novel Near-Infrared Imaging-Based, Quantitative Technique

Platelet-rich fibrin (PRF) matrices were originally prepared using plain glass tubes without the aid of coagulation factors because coagulation factor XII is activated by glass surfaces. Recently, the use of silica-coated plastic tubes as a substitute of glass tubes has been recommended for PRF preparation. This recommendation is owing not only to the shortage of glass tubes for medical use in the market, but also the higher coagulation activity of silica-coated plastic tubes and equal quality of PRF. However, these matrices are not the same. To evaluate the differences, we compared glass- and silica-coated plastic tubes in terms of platelet distribution and quantity in concentrated growth factors (CGF). CGF matrices were immediately prepared from freshly collected blood samples, fixed after red thrombus removal, and divided into two equal pieces sagittally. One piece was used for CD41 detection and the other was applied as an isotype control. Platelet distribution in CGF matrices was examined, without embedding or sectioning, by a novel method using invisible near-infrared imaging. The dehydrated membranous CGF matrix was more transparent. Thus, the fluorescence signal was clearly detectable with less scattering. Platelets were distributed mainly in the distal side of the glass-prepared CGF matrix, but homogeneously in the silica-prepared CGF matrix. Platelet count was positively correlated with fluorescence intensity. Although not yet fully developed, this imaging technique enabled us to recognize the differences in platelet distribution and quantity in CGF matrices by excluding bias caused by the technical limitations of scanning electron microscopy and conventional immunohistochemical methods.