Análisis inmunohistológico del aspirado intracoronario en pacientes con IAMCEST: implicaciones clínicas de los hallazgos anatomopatológicos

To Gain Insights into the Pathophysiological Mechanisms of the Thrombo-Inflammatory Process in the Atherosclerotic Plaque

Thromboinflammation, the interplay between thrombosis and inflammation, is a significant pathway that drives cardiovascular and autoimmune diseases, as well as COVID-19. SARS-CoV-2 causes inflammation and blood clotting issues. Innate immune cells have emerged as key modulators of this process. Neutrophils, the most predominant white blood cells in humans, are strategically positioned to promote thromboinflammation. By releasing decondensed chromatin structures called neutrophil extracellular traps (NETs), neutrophils can initiate an organised cell death pathway. These structures are adorned with histones, cytoplasmic and granular proteins, and have cytotoxic, immunogenic, and prothrombotic effects that can hasten disease progression. Protein arginine deiminase 4 (PAD4) catalyses the citrullination of histones and is involved in the release of extracellular DNA (NETosis). The neutrophil inflammasome is also required for this process. Understanding the link between the immunological function of neutrophils and the procoagulant and proinflammatory activities of monocytes and platelets is important in understanding thromboinflammation. This text discusses how vascular blockages occur in thromboinflammation due to the interaction between neutrophil extracellular traps and ultra-large VWF (von Willebrand Factor). The activity of PAD4 is important for understanding the processes that drive thromboinflammation by linking the immunological function of neutrophils with the procoagulant and proinflammatory activities of monocytes and platelets. This article reviews how vaso-occlusive events in thrombo-inflammation occur through the interaction of neutrophil extracellular traps with von Willebrand factor. It highlights the relevance of PAD4 in neutrophil inflammasome assembly and neutrophil extracellular traps in thrombo-inflammatory diseases such as atherosclerosis and cardiovascular disease. Interaction between platelets, VWF, NETs and inflammasomes is critical for the progression of thromboinflammation in several diseases and was recently shown to be active in COVID-19.

Thromboembolic Disease and Cardiac Thrombotic Complication in COVID-19: A Systematic Review

The coronavirus 2019 pandemic has affected many healthcare systems worldwide. While acute respiratory distress syndrome (ARDS) has been well-documented in COVID-19, there are several cardiovascular complications, such as myocardial infarction, ischaemic stroke, and pulmonary embolism, leading to disability and death. The link between COVID-19 and increasing thrombogenicity potentially occurs due to numerous different metabolic mechanisms, ranging from endothelial damage for direct virus infection, associated excessive formation of neutrophil extracellular traps (NETs), pathogenic activation of the renin-angiotensin-aldosterone system (RAAS), direct myocardial injury, and ischemia induced by respiratory failure, all of which have measurable biomarkers. A search was performed by interrogating three databases (MEDLINE; MEDLINE In-Process and Other Non-Indexed Citations, and EMBASE). Evidence from randomized controlled trials (RCT), prospective series, meta-analyses, and unmatched observational studies were evaluated for the processing of the algorithm and treatment of thromboembolic disease and cardiac thrombotic complications related to COVID-19 during SARS-CoV-2 infection. Studies out with the SARS-Cov-2 infection period and case reports were excluded. A total of 58 studies were included in this analysis. The role of the acute inflammatory response in the propagation of the systemic inflammatory sequelae of the disease plays a major part in determining thromboembolic disease and cardiac thrombotic complication in COVID-19. Some of the mechanisms of activation of these pathways, alongside the involved biomarkers noted in previous studies, are highlighted. Inflammatory response led to thromboembolic disease and cardiac thrombotic complications in COVID-19. NETs play a pivotal role in the pathogenesis of the inflammatory response. Despite moving into the endemic phase of the disease in most countries, thromboembolic complications in COVID-19 remain an entity that substantially impacts the health care system, with long-term effects that remain uncertain. Continuous monitoring and research are required.

Insights into the Role of Neutrophils and Neutrophil Extracellular Traps in Causing Cardiovascular Complications in Patients with COVID-19: A Systematic Review

Background: The coronavirus disease 2019 (COVID-19) pandemic caused by the SARS-CoV-2 virus has resulted in significant mortality and burdening of healthcare resources. While initially noted as a pulmonary pathology, subsequent studies later identified cardiovascular involvement with high mortalities reported in specific cohorts of patients. While cardiovascular comorbidities were identified early on, the exact manifestation and etiopathology of the infection remained elusive. This systematic review aims to investigate the role of inflammatory pathways, highlighting several culprits including neutrophil extracellular traps (NETs) which have since been extensively investigated. Method: A search was conducted using three databases (MEDLINE; MEDLINE In-Process & Other Non-Indexed Citations and EMBASE). Data from randomized controlled trials (RCT), prospective series, meta-analyses, and unmatched observational studies were considered for the processing of the algorithm and treatment of inflammatory response during SARS-CoV-2 infection. Studies without the SARS-CoV-2 Infection period and case reports were excluded. Results: A total of 47 studies were included in this study. The role of the acute inflammatory response in the propagation of the systemic inflammatory sequelae of the disease plays a major part in determining outcomes. Some of the mechanisms of activation of these pathways have been highlighted in previous studies and are highlighted. Conclusion: NETs play a pivotal role in the pathogenesis of the inflammatory response. Despite moving into the endemic phase of the disease in most countries, COVID-19 remains an entity that has not been fully understood with long-term effects remaining uncertain and requiring ongoing monitoring and research.

Assessment of Neutrophil Extracellular Traps in Coronary Thrombus of a Case Series of Patients With COVID-19 and Myocardial Infarction

Importance

Severe coronavirus disease 2019 (COVID-19) is characterized by the intense formation of neutrophil extracellular traps (NETs), leading to the occlusion of microvessels, as shown in pulmonary samples. The occurrence of ST-elevated myocardial infarction (STEMI) is a serious cardiac manifestation of COVID-19; the intrinsic mechanism of coronary thrombosis appears to still be unknown.

Objective

To determine the role of NETs in coronary thrombosis in patients with COVID-19.

Design, Setting, and Participants

This was a consecutive series of patients with COVID-19 at an academic tertiary hospital in Madrid, Spain, who underwent primary coronary interventions for STEMI in which coronary aspirates were obtained in the catheterization laboratory using a thrombus aspiration device. Patients with COVID-19 who experienced a STEMI between March 23 and April 11, 2020, from whom coronary thrombus samples were aspirated during primary coronary intervention, were included in the analysis. These patients were compared with a series conducted from July 2015 to December 2015 of patients with STEMI.

Main Outcomes and Measures

The presence and quantity of NETs in coronary aspirates from patients with STEMI and COVID-19. The method for the analysis of NETs in paraffin-embedded coronary thrombi was based on the use of confocal microscopy technology and image analysis for the colocalization of myeloperoxidase-DNA complexes and citrullinated histone H3. Immunohistochemical analysis of thrombi was also performed. Clinical and angiographic variables were prospectively collected.

Results

Five patients with COVID-19 were included (4 men [80%]; mean [SD] age, 62 [14] years); the comparison group included 50 patients (44 males [88%]; mean [SD] age, 58 [12] years). NETs were detected in the samples of all 5 patients with COVID-19, and the median density of NETs was 61% (95% CI, 43%-91%). In the historical series of patients with STEMI, NETs were found in 34 of 50 thrombi (68%), and the median NET density was 19% (95% CI, 13%-22%; P < .001). All thrombi from patients with COVID-19 were composed of fibrin and polymorphonuclear cells. None of them showed fragments of atherosclerotic plaque or iron deposits indicative of previous episodes of plaque rupture.

Conclusions and Relevance

In this small case series of patients with COVID-19 and myocardial infarction, NETs seem to play a major role in the pathogenesis of STEMI in COVID-19 disease. Our findings support the idea that targeting intravascular NETs might be a relevant goal of treatment and a feasible way to prevent coronary thrombosis in patients with severe COVID-19 disease.

A simple score to select patients for manual thrombectomy in emergent percutaneous coronary interventions: the DDTA score

BACKGROUND

The objective of manual thrombectomy is the removal of occlusive thrombus to improve the results of primary angioplasty. The better understanding of the factors associated with successful manual thrombectomy may provide relevant information regarding thrombus formation and resolution.

METHODS

Observational study of all consecutive patients remitted for emergent percutaneous coronary intervention (PCI) in a single centre. Successful manual thrombectomy was considered when TIMI 3 was achieved after using the device and a score to predict successful manual thrombectomy was designed.

RESULTS

We included 618 patients, 65.1% treated with manual thrombectomy. No relevant differences in clinical features or time delays were observed between patients treated with vs. without manual thrombectomy, but manual thrombectomy treated patients received more often dual antiplatelet treatment (DAPT) before PCI. Final TIMI flow 3 was achieved in most patients and more frequently in manual thrombectomy treated patients (94.8 vs. 86.6%; P < 0.01). The successful manual thrombectomy rate was 81.3% and it was higher in patients pretreated with DAPT (89.0 vs. 73.3%; P < 0.01). The time delay to first medical contact was not related to the final TIMI 3, but it was significantly and negatively related to successful manual thrombectomy. According to the multivariate analysis, we designed the DDTA score: DAPT pretreatment (2), delay less than 2 h (3) or 2-4 h (2), TIMI flow improvement after wiring the lesion (2) and age less than 55 years (3). Patients with DDTA score at least 4 had lower no-reflow, mortality and major cardiovascular complications incidence.

CONCLUSION

The DDTA score (DAPT pretreatment, time delays, TIMI flow improvement after wiring the lesion and age) identifies patients who benefit mostly from manual thrombectomy.

Cell-free DNA and Microvascular Damage in ST-segment Elevation Myocardial Infarction Treated With Primary Percutaneous Coronary Intervention

INTRODUCTION AND OBJECTIVES

Cell-free DNA (cfDNA) in ST-segment elevation myocardial infarction might originate from hyperactivated leukocytes at the coronary lesion. Our aim was to investigate the relationship between cfDNA and coronary reperfusion.

METHODS

We studied 116 patients treated with primary angioplasty using thrombus aspiration. Coronary (during aspiration) and peripheral (at the end of the procedure) blood samples were drawn for cfDNA, as well as high-sensitivity troponin T and myeloperoxidase quantification. The primary endpoint was no ST-segment resolution (STR) (≥ 70%) and the secondary endpoint was lack of final Thrombolysis In Myocardial Infarction flow 3 (TIMI 3).

RESULTS

ST-segment resolution was achieved in 51 (44%) patients and TIMI 3 flow in 97 (84%). Patients without STR and TIMI 3 flow had a smaller peripheral-coronary cfDNA gradient (P = .02 and P = .04 respectively). A small cfDNA gradient (< 1.82 ng/mL) was associated with a higher rate of no STR (65% vs 30%; P = .001) and lack of TIMI 3 flow (21% vs 3%; P = .05). After multivariable adjustment, the small cfDNA gradient was predictive of no STR (OR, 4.50; 95%CI, 1.60-12.62; P = .004), while there was a nonsignificant trend for final TIMI 3 flow (P = .14). Cell-free DNA levels did not correlate with troponin T or myeloperoxidase.

CONCLUSIONS

A small peripheral-coronary cfDNA gradient, as an expression of high coronary cfDNA burden, is associated with no STR in acute myocardial infarction. Intracoronary cfDNA might reflect neutrophil activation. Whether this phenomenon contributes to thrombus aspiration failure requires further study.