Characteristics of the Pathological Images of Coronary Artery Thrombi According to the Infarct-Related Coronary Artery in Acute Myocardial Infarction

The Inflammasome Signaling Pathway Is Actively Regulated and Related to Myocardial Damage in Coronary Thrombi from Patients with STEMI

Background

The Nod-Like-Receptor-Protein-3 (NLRP3) inflammasome and the Interleukin-6 (IL-6) pathways are central mechanisms of the inflammatory response in myocardial reperfusion injury. Expanding our knowledge about the inflammasome signaling axis is important to improve treatment options. In a cross-sectional study, we aimed to study presence, localization, and genetic expression of inflammasome- and IL-6- signaling-related proteins in coronary thrombi and circulating leukocytes from ST-elevation myocardial infarction (STEMI) patients, with relation to myocardial injury and time from symptoms to PCI.

Methods

Intracoronary thrombi were aspirated from 33 STEMI patients. Blood samples were drawn. mRNA of Toll-Like-Receptor-4 (TLR4), NLRP3, caspase 1, Interleukin-1β (IL1-β), Interleukin-18 (IL-18), IL-6, IL-6-receptor (IL-6R), and glycoprotein 130 (gp130) were isolated from thrombi and circulating leukocytes and relatively quantified by RT-PCR. A part of each thrombus was embedded in paraffin for histology and immunohistochemistry analyses.

Results

Genes encoding the 8 markers were present in 76-100% of thrombi. Expression of TLR4 in thrombi significantly correlated to troponin T (r = 0.455, p = 0.013), as did NLRP3 (r = 0.468, p = 0.024). Troponin T correlated with expression in circulating leukocytes of TLR4 (r = 0.438, p = 0.011), NLRP3 (r = 0.420, p = 0.0149), and IL-1β (r = 0.394, p = 0.023). IL-6R expression in thrombi correlated significantly to troponin T (r = 0.434, p = 0.019), whereas gp130 was inversely correlated (r = −0.398, p = 0.050). IL-6 in circulating leukocytes correlated inversely to troponin T (r = −0.421, p = 0.015). There were no significant correlations between genes expressed in thrombi and time from symptom to PCI.

Conclusions

The inflammasome signaling pathway was actively regulated in coronary thrombi and in circulating leukocytes from patients with STEMI, in association with myocardial damage measured by troponin T. This supports the strategy of medically targeting this pathway in treating myocardial infarction and contributes to sort out optimal timing and targets for anti-inflammatory treatment. The study is registered at clinicaltrials.gov with identification number NCT02746822.

Asymmetrical Forces Dictate the Distribution and Morphology of Platelets in Blood Clots

Primary hemostasis consists in the activation of platelets, which spread on the exposed extracellular matrix at the injured vessel surface. Secondary hemostasis, the coagulation cascade, generates a fibrin clot in which activated platelets and other blood cells get trapped. Active platelet-dependent clot retraction reduces the clot volume by extruding the serum. Thus, the clot architecture changes with time of contraction, which may have an important impact on the healing process and the dissolution of the clot, but the precise physiological role of clot retraction is still not completely understood. Since platelets are the only actors to develop force for the retraction of the clot, their distribution within the clot should influence the final clot architecture. We analyzed platelet distributions in intracoronary thrombi and observed that platelets and fibrin co-accumulate in the periphery of retracting clots in vivo. A computational mechanical model suggests that asymmetric forces are responsible for a different contractile behavior of platelets in the periphery versus the clot center, which in turn leads to an uneven distribution of platelets and fibrin fibers within the clot. We developed an in vitro clot retraction assay that reproduces the in vivo observations and follows the prediction of the computational model. Our findings suggest a new active role of platelet contraction in forming a tight fibrin- and platelet-rich boundary layer on the free surface of fibrin clots.

4-Hydroxyl-2-Nonenal Localized Expression Pattern in Retrieved Clots is Associated with Large Artery Atherosclerosis in Stroke Patients

OBJECTIVES

The relationship between stroke etiology and clot pathology remains controversial.

MATERIALS AND METHODS

We performed histological analysis of clots retrieved from 52 acute ischemic stroke patients using hematoxylin and eosin staining and immunohistochemistry (CD42b and oxidative/hypoxic stress markers). The correlations between clot composition and the stroke etiological group (i.e., cardioembolic, cryptogenic, or large artery atherosclerosis) were assessed.

RESULTS

Of the 52 clots analyzed, there were no significant differences in histopathologic composition (e.g., white blood cells, red blood cells, fibrin, and platelets) between the 3 etiological groups (P = .92). By contrast, all large artery atherosclerosis clots showed a localized pattern with the oxidative stress marker 4-hydroxyl-2-nonenal (P < .01). From all 52 clots, 4-hydroxyl-2-nonenal expression patterns were localized in 28.8% of clots, diffuse in 57.7% of clots, and no signal in 13.5% of clots.

CONCLUSIONS

A localized pattern of 4-hydroxyl-2-nonenal staining may be a novel and effective marker for large artery atherosclerosis (sensitivity 100%, specificity 82%).

Very Early Versus Early Percutaneous Coronary Intervention in Patients with Decreased e-GFR after Successful Fibrinolytic Therapy

Background:

Pharmacoinvasive strategy (PIS) is the alternative approach to primary percutaneous coronary intervention (PCI) if PCI capable center isn’t available especially in the developing countries. Our objective of the current study was to investigate the incidence of contrast induced nephropathy (CIN), the occurrence of no reflow phenomenon and major adverse cardiac events (MACE) in patients with decreased estimated glomerular filtration rate (e-GFR) after successful fibrinolytic therapy in order to assess the benefit from very early PCI strategy (within 3–12 hours) or early PCI strategy (within 12–24 hours).

Methods:

This randomized clinical trial included 420 patients with STEMI. All participants were classified randomly into two groups according to the time of intervention; Group I patients were subjected to very early PCI (within 3–12 hours) and Group II patients were subjected to early PCI (within 12–24 hours) after receiving successful fibrinolytic therapy.

Results:

The incidence of CIN in Group I was slightly higher than Group II (23 patients [10.7%] versus 19 patients [9.3%]) respectively, with no statistically significant difference between the two groups (P value = 0.625). The incidence of no-reflow phenomenon (TIMI 0–2 flow) after the procedure was higher in Group II, while TIMI 3 flow (normal flow) was significantly higher in Group I than Group II (184 [85.6%] vs. 153 [74.6%], respectively) with P value = 0.044. There was no statistically significant difference between the two groups regarding mortality and MACE.

Conclusion:

The incidence of CIN was nearly equal in very early PCI (within 3–12 hours) versus early PCI (within 12–24 hours); however, the incidence of no-reflow phenomenon was significantly higher in patients subjected to early PCI (within 12–24 hours).

Predictors and prognosis of no-reflow during primary percutaneous coronary intervention

The no-reflow phenomenon occurs in a considerable number of patients with ST elevation myocardial infarction (STEMI) undergoing primary reperfusion therapy. Our study aimed to identify clinical, angiographic, and procedural variables that predict this phenomenon in patients with STEMI undergoing primary percutaneous coronary intervention (PPCI), as well as determine the impact of no-reflow on in-hospital mortality. Prospective observational data from 410 patients with STEMI undergoing PPCI were obtained. In this study, diabetes mellitus, late presentation, higher Killip class at admission, anterior wall infarction, proximal site of occlusion, presence of high-grade thrombus, and left ventricular systolic dysfunction at admission were significantly associated with suboptimal coronary flow. Diabetes mellitus, a high thrombus burden, prolonged total ischemic time, and low left ventricular ejection fraction on admission were independent predictors of no-reflow. No-reflow during PPCI was associated with in-hospital mortality more than twice that for normal flow.

The predictors of no reflow phenomenon after percutaneous coronary intervention in patients with ST elevation myocardial infarction: A meta-analysis

OBJECTIVE

To investigate the no reflow risk factors after percutaneous coronary intervention in ST elevation myocardial infarction patients.

METHOD

Sample size, mean±standard deviation (SD) or frequencies (percent) of normal and no reflow groups were extracted from each study.

RESULTS

Of 27 retrospective and prospective studies, we found that increasing risks of no reflow were associated with advanced age, male, family history of coronary artery disease, smoking, diabetes mellitus, hypertension, delayed reperfusion, killip class ≥2, elevated blood glucose, increased creatinine, elevated creatine kinase (CK), higher heart rate, decreased left ventricular ejection fraction (LVEF), collateral flow ≤1, longer lesion length, multivessel disease, reference luminal diameter, initial thrombolysis in myocardial infarction (TIMI) flow, and high thrombus burden. Moreover, initial TIMI flow ≤1 and high thrombus burden had the greater impact on no reflow (OR95%CI=3.83 [2.77-5.29], p<0.0001 and 3.69 [2.39-5.68], p<0.0001, respectively).

CONCLUSION

Our meta-analysis reveals that initial TIMI flow ≤1 and high thrombus burden are the most impacted no reflow risk factors.

Combination of magnetic resonance imaging and targeted contrast agent for the diagnosis of myocardial infarction

Myocardial infarction is one of the most common human cerebrovascular conditions and frequently leads to ischemic stroke. Evidence has indicated that magnetic resonance imaging (MRI) is a potential method for the diagnosis of patients with cardiovascular injury. However, the efficacy of MRI in diagnosing patients with myocardial infarction requires to be improved. In the present study, a novel nano-size contrast agent, a chitosan/Fe₃O₄-enclosed albumin (CFEA), was introduced that was used to quantify blood volume and permeability in the infarcted myocardium. A total of 68 patients with suspected myocardial infarction were recruited to analyze the efficacy of MRI combined with CFEA (MRI-CFEA). All patients received diagnosis by MRI and MRI-CFEA. It was revealed that MRI-CFEA provided a higher signal intensity than MRI in the same patients. It was demonstrated that the diagnostic efficacy of MRI-CFEA for patients with myocardial infarction was higher than that of MRI (P<0.05). By MRI-CFEA, 50/68 of cases with myocardial infarction were diagnosed, providing a significantly higher diagnostic rate compared with the 38/68 of cases diagnosed by contrast-enhanced MRI (P<0.01). MRI-CFEA successfully discriminated the infarcted regions based on a decreased fractional blood volume and increased permeability-surface (PS) area product in the infarcted myocardium. A pharmacodynamics analysis indicated that CFEA was eliminated within 24 h in all individuals. In conclusion, the present study provided a novel method to diagnose infarcted myocardium for patients with myocardial infarction, providing an imaging biomarker for the assessment of endothelial dysfunction in the clinic.

Evidence for polymicrobial communities in explanted vascular filters and atheroma debris

RATIONALE

Microbial communities have been implicated in a variety of disease processes and have been intermittently observed in arterial disease; however, no comprehensive unbiased community analysis has been performed. We hypothesize that complex microbial communities may be involved in chronic vascular diseases as well and may be effectively characterized by molecular assays.

OBJECTIVE

The main objective is to survey vascular debris, atheroma, and vascular filters for polymicrobial communities consisting of prokaryotic and eukaryotic microbes, specifically eukaryotic microbes.

METHODS AND RESULTS

We examined vascular aspirates of atheromatous debris or embolic protection filters in addition to matched peripheral blood samples, from fifteen patients, as well as three cadaveric coronary arteries from two separate patients, for microbial communities. General fluorescence microscopy by Höechst and ethidium bromide DNA stains, prokaryotic and eukaryotic community analysis by Next Generation DNA Sequencing (NGS), and a eukaryotic microbial 9 probe multiplexed quantitative PCR were used to detect and characterize the presence of putative polymicrobial communities. No prokaryotes were detected in peripheral blood; however, in 4 of 9 sequenced filters and in 2 of 7 sequenced atheroma debris samples, prokaryotic populations were identified. By DNA sequencing, eukaryotic microbes were detected in 4 of 15 blood samples, 5 of the 9 sequenced filters, and 3 of the 7 atheroma debris samples. The quantitative multiplex PCR detected sequences consistent with eukaryotic microbes in all 9 analyzed filter samples as well as 5 of the 7 atheroma debris samples. Microscopy reveals putative polymicrobial communities within filters and atheroma debris. The main contributing prokaryotic species in atheroma debris suggest a diverse and novel composition. Additionally, Funneliformis mosseae, an arbuscular mycorrhizal fungus in the Glomeraceae family, was detected in the coronary hard plaque from two patients. Well studied biofilm forming bacteria were not detectable in circulating peripheral blood and were not universally present in atheroma or filters. Analyses of the sequenced eukaryotes are consistent with a diverse of array poorly studied environmental eukaryotes. In summary, out of 15 patients, 6 exhibited molecular evidence of prokaryotes and 14 had molecular evidence of eukaryotic and/or polymicrobial communities in vivo, while 2 post-mortem coronary plaque samples displayed evidence of fungi.

CONCLUSION

Prokaryotes are not consistently observed in atheroma debris or filter samples; however, detection of protozoa and fungi in these samples suggests that they may play a role in arterial vascular disease or atheroma formation.

Predictors of no- reflow during primary angioplasty for acute myocardial infarction, from Medical College Hospital, Trivandrum

Background

Primary angioplasty (PCI) for acute myocardial infarction is associated with no-reflow phenomenon, in about 5–25% of cases. Here we analysed the factors predicting no reflow .

Methods

This was a case control study of consecutive patients with acute myocardial infarction who underwent Primary PCI from August 2014 to February 2015.

Results

Of 181 patients who underwent primary PCI, 47 (25.9%) showed an angiographic no-reflow phenomenon. The mean age was 59.19 ± 10.25 years and females were 11%.

Univariate predictors of no reflow were age >60 years (OR = 6.146, 95%CI 2.937–12.86, P = 0<0.001), reperfusion time >6 h (OR = 21.94, 95%CI 9.402–51.2, P = < 0.001), low initial TIMI flow (≤1) (OR = 12.12, 95%CI 4.117–35.65, P < 0.001), low initial TMPG flow (≤1) (OR = 36.19, 95%CI 4.847–270.2, P < 0.001) a high thrombus burden (OR = 11.04,95%CI 5.124–23.8, P < 0.001), a long target lesion (OR = 8.54, 95%CI 3.794–19.23, P < 0.001), Killip Class III/IV(OR = 2.937,95%CI 1.112–7.756,P = 0.025) and overlap stenting(OR = 3.733,95%CI 1.186–11.75,P = 0.017).

Multiple stepwise logistic regression analysis predictors were: longer reperfusion time > 6 h (OR = 13.844, 95%CI 3.214–59.636, P = <0.001), age >60 years (OR = 8.886, 95%CI 2.145–36.80, P = 0.003), a long target lesion (OR = 8.637, 95%CI 1.975–37.768, P = 0.004), low initial TIMI flow (≤1) (OR = 20.861, 95%CI 1.739–250.290, P = 0.017).

Conclusions

It is important to minimize trauma to the vessel, avoid repetitive balloon dilatations use direct stenting and use the shortest stent if possible.

Oral anticoagulants in coronary heart disease (Section IV). Position paper of the ESC Working Group on Thrombosis - Task Force on Anticoagulants in Heart Disease

Until recently, vitamin K antagonists (VKAs) were the only available oral anticoagulants evaluated for long-term treatment of patients with coronary heart disease (CHD), particularly after an acute coronary syndrome (ACS). Despite efficacy in this setting, VKAs are rarely used because they are cumbersome to administer. Instead, the more readily manageable antiplatelet agents are the mainstay of prevention in ACS patients. This situation has the potential to change with the introduction of non-VKA oral anticoagulants (NOACs), which are easier to administer than VKAs because they can be given in fixed doses without routine coagulation monitoring. The NOACs include dabigatran, which inhibits thrombin, and apixaban, rivaroxaban and edoxaban, which inhibit factor Xa. Apixaban and rivaroxaban were evaluated in phase III trials for prevention of recurrent ischaemia in ACS patients, most of whom were also receiving dual antiplatelet therapy with aspirin and clopidogrel. Although at the doses tested rivaroxaban was effective and apixaban was not, both agents increased major bleeding. The role for the NOACs in ACS management, although promising, is therefore complicated, because it is uncertain how they compare with newer antiplatelet agents, such as prasugrel, ticagrelor or vorapaxar, and because their safety in combination with these other drugs is unknown. Ongoing studies are also now evaluating the use of NOACs in non-valvular atrial fibrillation patients, where their role is established, with coexistent ACS or coronary stenting. Focusing on CHD, we review the results of clinical trials with the NOACs and provide a perspective on their future incorporation into clinical practice.

Associations between circulating proteins and corresponding genes expressed in coronary thrombi in patients with acute myocardial infarction

INTRODUCTION

Several genes are expressed in aspirated coronary thrombi in acute myocardial infarction (AMI), exhibiting dynamic changes along ischemic time. Whether soluble biomarkers reflect the local gene environment and ischemic time is unclear. We explored whether circulating biomarkers were associated with corresponding coronary thrombi genes and total ischemic time.

MATERIAL AND METHODS

In 33 AMI patients undergoing percutaneous coronary intervention (PCI), blood samples were collected within 6-24h for markers related to plaque rupture (metalloproteinase 9, tissue inhibitor of metalloproteinases 1), platelet and endothelial cell activation (P-selectin, CD40 ligand, PAR-1), hemostasis (tissue factor, tissue plasminogen activator, plasminogen activator inhibitor 1, free and total tissue factor pathway inhibitor, D-dimer, prothrombin fragment 1+2), inflammation (interleukin 8 and 18, fractalkine, monocyte chemoattractant protein 1 (MCP-1), CXCL1, pentraxin 3, myeloperoxidase) and galectin 3, caspase 8 and epidermal growth factor (EGF). Laboratory analyses were performed by Proximity Extension Assay (Proseek Multiplex CVD I(96 × 96)), ELISAs and RT-PCR.

RESULTS

Only circulating P-selectin correlated to the corresponding P-selectin gene expression in thrombi (r=0.530, p=0.002). Plasma galectin 3, fractalkine, MCP-1 and caspase 8 correlated inversely to ischemic time (r=-0.38-0.50, all p <0.05), while plasma MCP-1, galectin 3 and EGF were higher at short (≤ 4 h) vs. long (>4h) ischemic time (all p <0.05).

CONCLUSIONS

The dynamic changes in circulating mediators along ischemic time were not reflected in the profile of locally expressed genes. These observations indicate a locally confined milieu within the site of atherothrombosis, which may be important for selective therapy.

Clinical significance of no-reflow in different stages of primary angioplasty among patients with acute myocardial infarctions

Background:

The coronary no-reflow (NR) phenomenon, which is associated with poor clinical outcomes, is usually referred to as a post-percutaneous coronary intervention (PCI) state. NR can occur in different stages of the PCI procedure, not only including the post-stenting stage, but from balloon pre-dilation to pre-stenting. The clinical significance of NR in the different stages of the PCI procedure is unclear. The purpose of the current study was to analyze the clinical and angiographic characteristics, the prognosis for NR patients in the aforementioned two stages and to determine the predictors of NR in the early stage.

Methods:

Between January 2009 and December 2013, a total of 420 consecutive patients with ST-segment elevation myocardial infarction (STEMI) underwent primary PCI. Sixty-three patients (15%) with NR constituted the study population. The patients were divided into an early NR group and a subsequent NR group. The clinical and angiographic findings were compared between the two groups. Multivariate logistic regression was used to determine the predictors for early NR. The long-term clinical outcomes after PCI were analyzed.

Results:

Regarding the baseline characteristics, we identified that the early NR group had statistically significant effects on the higher percentage of diabetes mellitus (42.9% vs. 20%), lower admission systolic blood pressure (SBP) (102.2±8.3 mmHg vs. 110.5±7.6 mmHg), higher percentage of Killip classification III (71.4% vs. 45.7%,) and longer reperfusion time (7.1±2.3 h vs. 5.88±2.2 h) compared to the subsequent NR group. There were significant differences between the two groups with respect to the percentage of initial thrombolysis in myocardial infarction (TIMI) flow 0/1 (64.3% vs. 37.1%), target lesion length (31.4±13.6 mm vs. 20.5±17.3 mm) and thrombus score ⩾4 (67.9% vs. 42.9%; p<0.05 for all). Multiple stepwise logistic regression analysis indicated that an admission SBP <100 mmHg (OR=4.580; 95% CI=1.385–15.150; p=0.0130), reperfusion time ⩾6 h (OR=4.978; 95% CI=1.468–16.882; p=0.010) and a thrombus score ⩾4 (OR=2.708; 95% CI=0.833–8.799; p=0.008) were the independent determinants of the early NR. During a 1-year follow-up, the all-cause mortality and overall major adverse cardiac events (MACEs) in the early NR group occurred significantly more often than in the subsequent NR group (28.6% vs. 5.7% and 35.7% vs. 14.3%, respectively, p <0.05). The early NR group had a lower left ventricular ejection fraction (LVEF) (42.5±4.7 vs. 47.8±3.5, p <0.001) and a larger left ventricular end diastolic diameter (LVEDD) (56.0±4.0 vs. 51.5 ±4.7, p=0.001) at the end of the follow-up.

Conclusion:

Early NR patients during primary PCI have more severe baseline clinical and angiographic characteristics, as well as a poorer long-term prognosis.

Simple clinical risk score for no-reflow prediction in patients undergoing primary Percutaneous Coronary Intervention with acute STEMI

Objectives:

To identify the STEMI patients at high risk in terms of no-reflow during percutaneous coronary intervention (PCI) with a simple risk score system that can be used before reperfusion.

Methods:

Total 173 patients who had undergone primary or rescue percutaneous coronary intervention following the diagnosis of STEMI, were classified as “no-reflow” developers and “no-reflow” non-developers, during the procedure. The pre-procedural ECGs, laboratory parameters, demographic data, time for the treatment, and the treatment methods were evaluated with univariate analysis. The independent predictors were identified by multivariate logistic regression analysis among the no-reflow risk factors. Using the independent predictors, we developed a simple risk score system proportional to area under the ROC (AUROC) curves.

Results:

The independent predictors of “no-reflow” phenomenon were identified as follows: high values of blood glucose at reference; long symptom-onset-to-balloon-time; and low lymphocyte count. The incidence rates of “no-reflow” in patients with low (0-1), moderate (2-3) and high (4-6) risk factors were 13.3%, 40.0%, and 46.7%, respectively. The risk score system demonstrated a good risk prediction between patients with various risk levels of the development of “no-reflow” with a c-statistics of 0.734 (95% CI 0.654-0.814).

Conclusion:

The development of “no-reflow” which is an adverse event in STEMI treatment can be predicted efficiently by simple clinical risk scoring method.

Clinical and procedural predictors of no-reflow in patients with acute myocardial infarction after primary percutaneous coronary intervention

BACKGROUND

The treatment of acute myocardial infarction (AMI) is thought to restore antegrade blood flow in the infarct-related artery (IRA) and minimize ischemic damage to the myocardium as soon as possible. The present study aimed to identify possible clinical predictors for no-reflow in patients with AMI after primary percutaneous coronary intervention (PCI).

METHODS

A total of 312 consecutive patients with AMI who had been treated from January 2008 to December 2010 at the Cardiology Department of East Hospital, Tongji University School of Medicine were enrolled in this study. Inclusion criteria were: (i) patients underwent successfully primary PCI within 12 hours after the appearance of symptoms; or (ii) patients with ischemic chest pain for more than 12 hours after a successful primary PCI within 24 hours after appearance of symptoms. Exculsion criteria were: (i) coronary artery spasm; (ii) diameter stenosis of the culprit lesion was <50% and coronary blood flow was normal; (iii) patients with severe left main coronary or multivessel disease, who had to require emergency revascularization. According to thrombolysis in myocardial infarction (TIMI), the patients were divided into a reflow group and a no-reflow group. The clinical data, angiography findings and surgical data were compared between the two groups. Univariate and multivariate logistic regressions were used to determine the predictors for no-reflow.

RESULTS

Fifty-four (17.3%) of the patients developed NR phenomenon after primary PCI. Univariate analysis showed that age, time from onset to reperfusion, systolic blood pressure (SBP) on admission, Killip class of myocardial infarction, intra-aortic balloon pump (IABP) use before primary PCI, TIMI flow grade before primary PCI, type of occlusion, thrombus burden on baseline angiography, target lesion length, reference luminal diameter and method of reperfusion were correlated with no-reflow (P<0.05 for all). Multiple logistic regression analysis identified that age >65 years [OR=1.470, 95% confidence interval (CI) 1.460-1.490, P=0.007], long time from onset to reperfusion >6 hours (OR=1.270, 95%CI 1.160-1.400, P=0.001), low SBP on admission <100 mmHg (OR=1.910, 95%CI 1.018-3.896, P=0.004), IABP use before PCI (OR= 1.949, 95%CI 1.168-3.253, P=0.011), low (≤1) TIMI flow grade before primary PCI (OR=1.100, 95%CI 1.080-1.250, P<0.001), high thrombus burden (OR=1.600, 95%CI 1.470-2.760, P=0.030), and long target lesion (OR=1.948, 95%CI 1.908-1.990, P=0.019) on angiography were independent predictors of no-reflow.

CONCLUSION

The occurrence of no-reflow after primary PCI for acute myocardial infarction can predict clinical, angiographic and procedural features.

Clinical significance of histological features of thrombi in patients with myocardial infarction

Background

Percutaneous Coronary Intervention (PCI) is the most common strategy for the treatment of Acute ST segment elevation Myocardial Infarction (STEMI), and thromboaspiration has been increasingly utilized for removal of occlusive thrombi.

Objectives

To analyze the influence of histopathological features of coronary thrombi in clinical outcomes of patients with STEMI, and the association of these variables with clinical, angiographic, and laboratory features and medications used in hospitalization.

Methods

Prospective cohort study. All patients were monitored during hospitalization and thirty days after the event. Aspirated thrombi were preserved in formalin and subsequently stained with hematoxylin-eosin and embedded in paraffin. Thrombi were classified as recent and old. The primary outcome was the occurrence of major cardiovascular events within thirty days.

Results

During the study period, 1,149 patients were evaluated with STEMI, and 331 patients underwent thrombi aspiration, leaving 199 patients available for analysis. It was identified recent thrombi in 116 patients (58%) and old thrombi in 83 patients (42%). Recent thrombi have greater infiltration of red blood cells than old thrombi (p = 0.02), but there were no statistically significant differences between other clinical, angiographic, laboratory, and histopathological features and medications in both group of patients. The rates of clinical outcomes were similar in both groups.

Conclusions

Recent thrombi were identified in 58% of patients with STEMI and it was observed an association with infiltration of red blood cells. There was no association between histopathological features of thrombi and clinical variables and cardiovascular outcomes.

Relationship of thrombus characteristics to the incidence of angiographically visible distal embolization in patients with ST-segment elevation myocardial infarction treated with thrombus aspiration

OBJECTIVES

This study sought to investigate the association between pathological characteristics of aspirated intracoronary thrombi and the incidence of angiographically visible distal embolization (AVDE) during primary percutaneous coronary intervention (p-PCI) in patients with ST-segment elevation myocardial infarction (STEMI) treated with thrombus aspiration.

BACKGROUND

AVDE of atherosclerotic and thrombotic material has been shown to impair myocardial perfusion and contribute to poor clinical outcome in patients with STEMI. Recent studies have shown that thrombus composition and size are associated with the incidence of AVDE.

METHODS

Aspirated thrombi from 164 STEMI patients within 12 h of symptom onset were investigated immunohistochemically using antibodies against platelets, erythrocytes, and inflammatory cells.

RESULTS

The angiographic results showed that AVDE during p-PCI occurred in 22 (13.4%) patients. Pathological analysis revealed that thrombi from patients with AVDE had a greater erythrocyte-positive area (60 ± 15% vs. 43 ± 21%, p < 0.0005) and more myeloperoxidase-positive cells (943 ± 324 cells/mm(2) vs. 592 ± 419 cells/mm(2), p < 0.0005) than those from patients without AVDE. Thrombus size, quantified as the thrombus surface area, was positively correlated with the erythrocyte component (r = 0.362, p < 0.0001). Moreover, multivariate logistic analysis demonstrated that erythrocyte-positive area in the thrombi, glucose levels on admission, larger vessel diameter (≥ 3.5 mm), and pre-balloon dilation were independent predictors of the incidence of AVDE.

CONCLUSIONS

This study demonstrated that the erythrocyte-rich component of aspirated thrombi may be associated with the incidence of AVDE during p-PCI in patients with STEMI.

Cellularity and structure of fresh human coronary thrombectomy specimens; presence of cells with markers of progenitor cells

Acute coronary syndromes and acute myocardial infarctions are often related to plaque rupture and the formation of thrombi at the site of the rupture. We examined fresh coronary thrombectomy specimens from patients with acute coronary syndromes and assessed their structure and cellularity. The thrombectomy specimens consisted of platelets, erythrocytes and inflammatory cells. Several specimens contained multiple cholesterol crystals. Culture of thrombectomy specimens yielded cells growing in various patterns depending on the culture medium used. Culture in serum-free stem cell enrichment medium yielded cells with features of endothelial progenitor cells which survived in culture for a year. Immunohistochemical analysis of the thrombi revealed cells positive for CD34, cells positive for CD15 and cells positive for desmin in situ, whereas cultured cell from thrombi was desmin positive but pancytokeratin negative. Cells cultured in endothelial cell medium were von Willebrand factor positive. The content of coronary thrombectomy specimens is heterogeneous and consists of blood cells but also possibly cells from the vascular wall and cholesterol crystals. The culture of cells contained in the specimens yielded multiplying cells, some of which demonstrated features of haematopoietic progenitor cells and which differentiated into various cell-types.

Scavenger receptor A index and coronary thrombus in patients with acute ST elevation myocardial infarction

To examine the relationship between the scavenger receptor A (SRA) index (the number of SRA+ cells observed in 10 high power fields of peripheral blood (PB) smear samples; normal upper limit <30) and coronary thrombus, 389 thrombi obtained from 393 patients with acute ST elevation myocardial infarction were examined. Thrombi were classified into platelets (PT), mixed (MT), fibrin-rich (FT) and organizing thrombi (OT); 387, 269, 57 and 29 cases were detected, respectively. Patients were divided into group A (PT only, 89 cases), B (containing MT and PT but not FT, 243 cases), and C (containing FT, 57 cases). SRA+ cells had infiltrated into all FT cases and 147 of the 269 MT, but no PT. At hospitalization, the SRA index exceeded 30 in 276 patients. PT was observed in 274 cases, and MT and FT (residual mural thrombus; RMT) observed in 230. Infarct-related coronary artery was thought to be totally and rapidly occluded by PT that had formed as a result of severe stenosis due to extrusion of plaque content or growth of RMT. An abnormal increase of SRA+ cells is considered to be a useful finding to detecting the presence of PT and, probably, RMT.

Predictors and long-term prognosis of angiographic slow/no-reflow phenomenon during emergency percutaneous coronary intervention for ST-elevated acute myocardial infarction

OBJECTIVE

Angiographic slow/no-reflow during emergency percutaneous coronary intervention (PCI) in patients with ST-elevated acute myocardial infarction (AMI) may result in unfavorable outcomes. The aim of our study was to investigate the clinical factors and angiographic findings that predict slow/no-reflow phenomenon and the long-term prognosis of AMI patients with angiographic slow/no-reflow.

METHODS

A total of 210 consecutive AMI patients, who underwent primary PCI within 12 hours of symptom onset were divided into a normal flow group (thrombolysis in myocardial infarction [TIMI] flow grade 3, n = 169) and a slow/no-reflow group (≤TIMI flow grade 2, n = 41), based on cineangiograms performed during PCI.

RESULTS

A total of 41 patients (19.5%) developed slow/no-reflow phenomenon. Univariate analysis showed that delayed reperfusion, high thrombus burden on baseline angiography, and acute hyperglycemia all correlated with slow/no-reflow (P < 0.05 for all). Multivariate analysis revealed that hyperglycemia on admission (≥10 mmol/L; odds ratio [OR]: 1.7, 95% confidence interval [CI]: 1.423-2.971, P = 0.012), reperfusion time (≥6 h; OR:1.4, 95% CI: 1.193-1.695, P = 0.040), and high thrombus burden (OR: 1.6, 95% CI: 1.026-2.825, P = 0.031) were significant and independent predictors of angiographic slow/no-reflow. The 6-month mortality and incidence of major adverse cardiac and cerebrovascular events (MACCE) were significantly higher in the slow/no-reflow group than in the normal flow group. Angiographic slow/no-reflow was independently predictive of MACCE (hazard ratio [HR]: 2.642, 95% CI: 1.304-5.932, P = 0.028).

CONCLUSION

Delayed reperfusion, high thrombus burden on baseline angiography, and blood glucose level on admission can be used to stratify AMI patients into a lower or higher risk for angiographic slow/no-reflow during PCI. In addition, angiographic slow/no-reflow predicts an adverse outcome in AMI patients.

Eosinophils may be involved in thrombus growth in acute coronary syndrome

Thrombus aspiration therapy allows for the examination of thrombus and atheroma fragments in acute coronary syndrome (ACS). Inflammatory cells and platelet activation play key roles in thrombus formation in ACS. However, histopathologic evaluation of thrombi in ACS has not been adequately addressed. We performed histologic analysis of tissue samples obtained by thrombus aspiration therapy. We studied 165 samples from patients with ACS. The area of each sample, percentage of red thrombus, and percentage of white thrombus were measured. Samples were stained immunohistochemically with antibodies against macrophages, activated platelets, and interleukin (IL)-5. Seventy-six samples included atheroma fragments. Macrophages, neutrophils, and activated platelets were observed in thrombi and in atheroma fragments. Eosinophil infiltration was also observed predominantly in the area between white thrombus and red thrombus in 106 samples. We categorized all samples into 3 groups according to the grade of eosinophil infiltration (eos-, eos+, eos++ group). Sample area in the eos++ group was greater than that in the eos- group (P < 0.0001). In addition, the percentage of the red thrombus areas in the eos++ group and the eos+ group was greater than that in the eos- group (P < 0.009, P < 0.02, respectively). However, there was no difference in the percentage of white thrombus area between the 3 groups. Staining for IL-5 was identified in inflammatory cells within thrombi. Eosinophils may play an important role in coronary occlusion by promoting thrombus growth.

Impact of PercuSurge GuardWire device on prevention and reduction of recovery time from complete heart block in patients with acute inferior myocardial infarction undergoing primary percutaneous coronary intervention

Second-degree heart block or complete heart block (CHB) is a relatively frequent complication of acute inferior wall myocardial infarction (AIWMI). This study investigated whether the PercuSurge device can prevent procedure-related CHB or can shorten CHB recovery time in patients with AIWMI undergoing primary percutaneous coronary intervention (PCI). Between May 2002 and April 2005, a PercuSurge device was utilized in 113 patients (study population, group 1) with AIWMI due to obstruction of the right coronary artery (RCA) with a reference lumen diameter (RLD) > or = 3.5 mm. The control subjects (group 2) consisted of 119 patients who experienced AIWMI due to RCA obstruction with a RLD > or = 3.5 mm from May 2000 to April 2002. The combined incidence of new onset of CHB following the interventional procedure was significantly higher in group 2 than in group 1. Additionally, recovery time from CHB to first-degree heart block or normal sinus rhythm was remarkably longer in group 2 than in group 1. Furthermore, the duration of hospitalization in group 2 was significantly longer than in group 1. Multiple stepwise analyses demonstrated that the PercuSurge device was the only independent predictor of preventing new onset of CHB during the procedure. Additionally, this mechanical device along with final TIMI-3 flow and final myocardial blush grade > or = 2 was independently associated with reducing recovery time from CHB. In conclusion, the PercuSurge device can prevent procedure-related CHB and shorten the recovery time for CHB in patients with AIWMI undergoing primary PCI.

[Atypical presentation of right coronary artery occlusion]

INTRODUCTION

Inferior wall myocardial infarctions are usually benign and uncomplicated and rarely result in ventricular disturbances of the heart rhythm. An unusual presentation of an inferior acute myocardial infarction (AMI) with atypical symptoms, and ventricular tachycardia is described.

CASE REPORT

A 44-year-old patient was admitted to the coronary care unit (CCU) due to atypical chest pain during exercise and ECG abnormalities in leads L2, L3 and aVF. On admission, ECG could mimic myocarditis, pericardial effusion, left anterior bundle branch block or early repolarization. Two-dimensional echocardiography revealed a hypertrophic myocardium without abnormal regional wall motion, good left ventricular function and ejection fraction of 65%. The presumptive prediction of a culprit artery based on the ECG recorded on admission was conclusive for inferior AMI. Fibrinolytic therapy was started 3 hours after the onset of chest pain. Resolution of ST segment elevation and relief of chest pain occurred within one hour of the infusion. On the fifth day after admission, the patient had a nonsustained ventricular tachycardia (VT) which was resolved with amiodarone. Angiography showed acute occlusion of the mid portion, right coronary artery (RCA) and collateral circulation in the distal portion.

DISCUSSION AND CONCLUSION

Malignant ventricular arrhythmias can result from isolated inferior wall AMI, but literature reports on this phenomenon are rather rare. Collateral circulation can prevent myocardial ischemia and preserve myocardial function, but does not provide protection against exercise-induced myocardial ischemia.

Effects of thrombus suction therapy on myocardial blood flow disorders in males with acute inferior myocardial infarction

Several studies have reported that the use of a distal protection device decreases the incidence of slow-flow and/or no-reflow in patients with myocardial infarctions. In the present study, we investigated the influence of a RESCUE/Thrombuster system and a PercuSurge GuardWire catheter on coronary microcirculation disorders in patients with acute myocardial infarction using the natriuretic polypeptide (ANP), the brain natriuretic peptide (BNP), and (99m)Tc-tetrofosmin myocardial scintigraphy (TF). The group consisted of a 77 patients with initial inferior myocardial infarction who had undergone emergency coronary angioplasty. The patients were randomly divided into: Group D (n=28), in which a direct stent alone was inserted, Group R/T (n=25), in which a stent was inserted after RESCUE system or a Thrombuster system was performed, and Group P (n=24), in which a stent was inserted after thrombus suction using a PercuSurge GuardWire catheter. Patients with coronary slow-flow/no-reflow were 3, 2 and 0 cases in Group D, Group R / T and Group P, respectively. In the present study, patients with good-reflow were enrolled in order to investigate the coronary microcirculation disorder in patients with visually similar coronary blood flow obtained in coronary angiography after percutaneous coronary reperfusion therapy. TF myocardial scintigraphy was performed 10+/-3 days after admission. Bull's eye images were divided into 8 sections, and each section was evaluated in 4 grades. The grade of each segment was regarded as the defect score. The results were compared with the database prepared based on bull's eye maps from 50 healthy adults in our hospital, and count areas of -2 x SD (standard deviation) or less were calculated as the extent score (%), reflecting the area in which myocardial blood flow was decreased. The extent and severity scores in Groups P and R/T were significantly lower than those in Group D. Coronary angiography at the chronic stage (6 months after surgery) showed the patency of the responsible vascular lesion in all patients. However, the ANP, BNP, cardiac index, and pulmonary capillary wedge pressure (PCWP) were significantly improved in Groups R/T and P, compared to Group D (p<0.01). These results suggest that the use of a RESCUE/Thrombuster system and a PercuSurge GuardWire catheter system in patients with acute inferior wall infarction improves coronary microcirculation disorders and acute- to chronic-phase cardiac function.

Detection of von Willebrand factor and tissue factor in platelets-fibrin rich coronary thrombi in acute myocardial infarction

The rapid closure of coronary arteries due to occlusive thrombi is the major cause of acute myocardial infarction. However, the mechanisms of coronary thrombus formation have not been elucidated. We immunohistochemically assessed the localizations and their changes over time of glycoprotein IIb/IIIa, fibrin, von Willebrand factor (vWF), and tissue factor (TF), after the onset of chest pain (<4, 4 to 6, or 6 to 12 hours), in fresh coronary thrombi causing acute myocardial infarction. The occlusive thrombi were consistently composed of platelets, fibrin, vWF, and TF from the early phase of onset, and glycoprotein IIb/IIIa and fibrin were closely associated with vWF and TF, respectively. vWF and/or TF may contribute to occlusive thrombus formation and be novel therapeutic candidates for treating patients with coronary thrombosis.

Plaque instability frequently occurs days or weeks before occlusive coronary thrombosis: a pathological thrombectomy study in primary percutaneous coronary intervention

BACKGROUND

Acute ST-elevation myocardial infarction (STEMI) is caused by sudden occlusive coronary thrombosis, after plaque disruption; however, a considerable time interval between plaque disturbance and the onset of symptoms has been suggested. We therefore studied the age of intracoronary thrombi, aspirated during angioplasty in patients with acute STEMI.

METHODS AND RESULTS

Percutaneous intracoronary thrombectomy during angioplasty was performed in 211 consecutive STEMI patients within 6 hours after onset of anginal symptoms. The aspirated material was histologically screened on thrombus and plaque components, and thrombus age was classified as fresh (<1 day), lytic thrombus (1 to 5 days), and organized thrombus (>5 days). In all patients, intracoronary-derived material was retrieved in the filter of the collection bottle. Thrombus was identified in 199 (95%) of 211 patients. In 12 patients (5%), only plaque components were identified, and in 85 patients (41%), both thrombus and plaque material were aspirated. In 18 (9%) of 199 patients, the thrombus was organized, and in 70 patients (35%), the thrombus showed lytic changes, whereas in 98 (49%), a completely fresh thrombus was found. In 14 (7%) of 199 patients, the thrombus showed combined features of both fresh thrombus and organized thrombus.

CONCLUSIONS

In at least 50% of patients with acute STEMI, coronary thrombi were days or weeks old. This indicates that sudden coronary occlusion is often preceded by a variable period of plaque instability and thrombus formation, initiated days or weeks before onset of symptoms.

Acute Myocardial Infarction in a Patient With Essential Thrombocythemia Successful Treatment With Percutaneous Transluminal Coronary Recanalization

A 65-year-old woman with essential thrombocythemia (ET) was admitted to hospital where she was diagnosed as acute myocardial infarction (AMI). Because of abundant thrombus of right coronary arteries, percutaneous transluminal coronary recanalization by administration of urokinase was selected as the reperfusion therapy, resulting in successful revascularization with Thrombolysis in Myocardial Infarction grade III coronary flow. The maximum creatine kinase reached 507 IU/L, and left ventriculography performed at 1 month after initiation of both anticoagulant and antiplatelet therapies revealed reduced motion in the inferior wall with an ejection fraction of 57%. Despite good recovery of left ventricular function, bleeding complications, such as epistaxis or ecchymoma, which did not require blood transfusion, occurred during the clinical course. Because ET causes not only thrombus formation but also bleeding tendency, it is very important to carefully follow-up any clotting abnormality in AMI patients with ET.

Long-Term Clinical Outcomes of Platelet Glycoprotein IIb/IIIa Inhibitor Combined With Low Molecular Weight Heparin in Patients With Acute Coronary Syndrome

BACKGROUND

Platelet activation and aggregation with resultant arterial thrombus formation play a pivotal role in the pathophysiology of acute coronary syndrome (ACS). In the present study the efficacy of tirofiban, a specific inhibitor of the platelet glycoprotein IIb/IIIa receptor, combined with heparin or low-molecular-weight heparin (dalteparin), was evaluated for the management of ACS.

METHODS AND RESULTS

One hundred and sixty patients (60.9+/-11.1 years, 104 male) with unstable angina or non-ST elevation myocardial infarction and who had ST-T changes and elevated troponin were randomly assigned to 4 groups: group I (n=40: heparin alone), group II (n=40: dalteparin alone), group III (n=40: tirofiban + heparin) and group IV (n=40: tirofiban + dalteparin). The occurrence of major adverse cardiac events (MACE) was compared prospectively during a 6-month clinical follow-up. Percutaneous coronary intervention or coronary artery bypass graft was performed in 32 cases in group I, 29 in group II, 28 in group III and 31 in group IV (p=0.72). Minor bleeding complication developed in 2 patients (5.0%) in group I, 2 (5.0%) in group II, 4 (10.0%) in group III and 3 (7.5%) in group IV (p=0.78). During the follow-up MACE occurred in 10 patients (31.3%) in group I, 9 (31.0%) in group II, 4 (14.3%) in group III and 4 (12.9%) in group IV (p=0.02: Group I and II vs Group III and IV).

CONCLUSIONS

Tirofiban combined with dalteparin was associated with relatively more bleeding complications in the short term, but was effective in reducing the incidence of MACE during long-term clinical follow-up in patients with ACS.