Intramyocardial haemorrhage after acute myocardial infarction

The use of supersaturated oxygen therapy in patients with late-presentation anterior ST-segment elevation myocardial infarction

BACKGROUND

Patients with late-presentation anterior ST-elevation myocardial infarction (STEMI) are at increased risk of heart failure and mortality due to greater infarct size and microvascular injury including microvascular obstruction (MVO) and intramyocardial hemorrhage (IMH). Apart from primary percutaneous coronary intervention (PCI), no additional therapies are available for this high-risk group. Supersaturated oxygen therapy (SSO2) is utilized for anterior STEMIs with ischemic times under 6 h and may reduce infarct size. We investigated if SSO2 therapy may provide a clinical benefit for late-presentation anterior STEMI patients.

METHODS

SSO2 therapy was administered to 19 late-presentation anterior STEMI patients (12 males (M), 7 females (F); 60 yr.) for 60-min following primary PCI. Patients underwent cardiac MRI (CMR) prior to discharge for evaluation of infarct size, MVO, and IMH. Results were compared to a control group of 31 late-presentation anterior STEMI patients (19 M, 12F; 59 yr.) who received PCI and CMR but not SSO2.

RESULTS

The left anterior descending artery (LAD) was completely occluded in 89 % of SSO2 patients and 77 % of control patients prior to PCI. Final TIMI 3 flow was achieved in 84 % of all patients. Ejection fraction at baseline as well as infarct size, were similar between the two groups. Significantly fewer SSO2 patients had MVO (75 % vs 100 %, p = 0.01) and residual ST-segment elevation following PCI was significantly less in the SSO2 group suggestive of improved microvascular perfusion. Mortality was significantly reduced in the SSO2 group following STEMI compared to control patients (0 % vs 23 %, p = 0.03).

CONCLUSIONS

SSO2 can be safely delivered to late-presentation anterior STEMI patients and results in less MVO and less adverse events including all-cause mortality. SSO2 therapy may represent a new treatment for this high-risk patient group.

Long-term Prognostic Role of Persistent Microvascular Obstruction Determined by Cardiac Magnetic Resonance for ST-segment Elevation Myocardial Infarction

BACKGROUND

Microvascular occlusion (MVO) determined by cardiac magnetic resonance (CMR) exists both in acute phase and recovery period after myocardial infarction. This study aimed to examine the long-term prognosis predictive value of persistent MVO for ST-segment elevation myocardial infarction (STEMI).

METHODS

A prospective registry of 344 patients with STEMI who received primary percutaneous coronary intervention and underwent CMR both in 5-7 days and 6 months after STEMI to determine if MVO had occurred. All patients were followed up for 5 years, and major adverse cardiovascular events (MACE) were recorded.

RESULTS

This study included 344 STEMI patients with an average age of 57 years at six centers in China. A total of 192 (55.81%) patients with STEMI did not have MVO by CMR, and 105 (30.52%) patients showed transient MVO in acute phase of myocardial infarction and 47 (13.66%) patients showed persistent MVO at 6 months after infarction. The patients with persistent MVO had the largest infarct size and the lowest left ventricular ejection fraction both in 5-7 days and 6 months after infarction (all P<0.001). Patients with persistent MVO showed a significantly higher incidence of 5-years MACE than those without MVO or with MVO in only 1 week (66.0% vs. 18.8% and 27.6%, respectively; P < 0.001). Persistent MVO was an independent strong predictor of MACE after adjustment for other CMR variables (OR: 3.912, 95% CI: 1.904-8.037; P<0.001). A propensity score-matched population comprised 43 patients with persistent MVO and 43 patients with transient MVO in only 1 week. The patients with persistent MVO had a higher incidence of MACE than those with transient MVO (65.1% [28/43] vs. 37.2% [16/43]; P = 0.010).

CONCLUSION

Persistent MVO by CMR at the chronic phase of STEMI provides useful prognostic information regarding long-term outcomes after primary percutaneous coronary intervention.

Dissolving porcine and human microthrombi by short exposure to microdoses of alteplase in an in vitro model of microvascular obstruction

Coronary microvascular obstruction (MVO) occurs in up to 57% of patients suffering from ST-segment elevation myocardial infarction (STEMI). One cause for MVO is distal embolization by microthrombi after percutaneous coronary intervention (PCI) of the infarct-related coronary artery. MVO is associated with an adverse cardiac prognosis post-STEMI. However, there are no evidence-based therapies for MVO, presenting an unmet therapeutic need. We investigated a novel pharmacotherapeutic approach to resolve embolizing MVO using an in vitro microfluidic model with porcine or human microthrombi to investigate thrombolysis with alteplase, a fibrinolytic drug. We show that a brief (90 s) exposure to concentrated microdoses of alteplase significantly reduces microthrombus size by up to 75%. 50% lysis occurred within six to twelve minutes after alteplase exposure depending on the initial microdose. Our results suggest that delivering a therapeutic drug directly to the microvasculature to briefly achieve high local drug concentrations has the potential to address embolizing MVO. The combination of short drug exposure and high local concentration is possible with a recently developed infusion system based on intracoronary controlled flow infusion (CoFI). CoFI uses microdoses of alteplase that are up to 1300 times lower than intravenous doses and could thereby minimize bleeding risk.

Application of Myocardial Salvage Index as a Clinical Endpoint: Assessment Methods and Future Prospects

In patients with acute myocardial infarction (AMI), traditional clinical endpoints used to assess drug efficacy and prognosis include infarct size (IS), incidence of heart failure, and mortality rates. Although these metrics are commonly employed to evaluate outcomes in AMI patients, their utility is limited in small-scale studies. The introduction of the myocardial salvage index (MSI) reduces variability in assessments across multiple dimensions, thereby enhancing the sensitivity of outcome measures and reducing the required sample size. Moreover, MSI is increasingly utilized to evaluate drug efficacy, prognosis, and risk stratification in AMI patients. Although a variety of methodologies for measuring the MSI are currently available, the incorporation of these methods as clinical endpoints remains limited. In the clinical application of cardioprotective strategies, it is recommended that MSI be evaluated using late gadolinium enhancement measured along the endocardial surface length combined with IS in cardiac magnetic resonance. In dynamic single-photon emission computed tomography, an assessment of MSI using methods based on abnormalities in myocardial wall thickening combined with perfusion anomalies is advocated. This review comprehensively outlines the principles, advantages, and limitations of different MSI assessment methods and discusses the prospects and challenges of MSI in cardiac protective therapies. Additionally, we summarize recommended strategies for employing MSI as a clinical surrogate endpoint in various clinical scenarios, providing direction for future clinical practice and research. EVIDENCE LEVEL: 5 TECHNICAL EFFICACY: Stage 4.

Association of Intramyocardial Hemorrhage With Inflammatory Biomarkers in Patients With ST-Segment Elevation Myocardial Infarction

BACKGROUND

Ischemia-reperfusion (I/R) injury patterns detected by cardiac magnetic resonance imaging after percutaneous coronary intervention (PCI) have important prognostic implications and trigger inflammatory processes that can further enhance myocardial tissue damage.

OBJECTIVES

The authors aimed to investigate the association of circulating inflammatory markers and I/R injury patterns in patients with ST-segment elevation myocardial infarction (STEMI).

METHODS

This observational study included 456 STEMI patients. Peripheral venous blood samples were drawn 48 hours after PCI for analysis of high-sensitivity C-reactive protein (hs-CRP), white blood cell count (WBCc), and interleukin (IL)-6. The presence of I/R injury was defined by the detection of intramyocardial hemorrhage (IMH) according to cardiac magnetic resonance T2∗. Clinical endpoint was the occurrence of major adverse cardiac events, defined as composite of all-cause death, nonfatal reinfarction, and new congestive heart failure.

RESULTS

IMH was present in 150 (33%) patients. Hs-CRP (OR: 2.89; 95% CI: 1.96-4.26; P < 0.001), WBCc (OR: 1.32; 95% CI: 1.04-1.67; P = 0.021), and IL-6 (OR: 1.86; 95% CI: 1.38-2.51; P < 0.001) were associated with presence of IMH. Only hs-CRP was independently associated with IMH (OR: 1.95; 95% CI: 1.30-2.93; P = 0.001) after adjustment for other clinical parameters. Furthermore, patients with hs-CRP levels above the median (>26.4 mg/L) were more likely to experience major adverse cardiac events (12% vs 4%, P = 0.002) during a median follow-up of 12 (Q1-Q3: 12-13) months.

CONCLUSIONS

In patients with STEMI treated with primary PCI, inflammatory parameters including hs-CRP, WBCc, and IL-6 were significantly associated with I/R injury as defined by IMH. After adjustment for other factors, hs-CRP was the only independent inflammatory biomarker associated with IMH.

Detecting Hemorrhagic Myocardial Infarction With 3.0-T CMR: Insights Into Spatial Manifestation, Time-Dependence, and Optimal Acquisitions

BACKGROUND

Hemorrhagic myocardial infarction (hMI) can rapidly diminish the benefits of reperfusion therapy and direct the heart toward chronic heart failure. T2∗ cardiac magnetic resonance (CMR) is the reference standard for detecting hMI. However, the lack of clarity around the earliest time point for detection, time-dependent changes in hemorrhage volume, and the optimal methods for detection can limit the development of strategies to manage hMI.

OBJECTIVES

The authors investigated CMR signal characteristics of hMI through time-lapse multiparametric mapping using a clinically relevant animal model and evaluated the translatability in ST-segment elevation MI patients when possible.

METHODS

Canines (N = 20) underwent 3.0-T CMR at baseline and various time points over the first week of reperfused MI. Time-dependent relationships between T1, T2, and T2∗ mapping of hMI, non-hMI, and remote territories were determined. Reperfused ST-segment elevation MI patients (N = 50) were studied to establish clinically feasibility.

RESULTS

Although hMI was evident <1 hour after reperfusion on histopathology, it was not reliably detected with T1, T2, or T2∗ CMR. However, 24 hours to 7 days postreperfusion, hMI was detectable on T2∗ (27.0 ± 2.4 ms [baseline] vs 11.7 ± 2.8 ms [hMI]; P < 0.001), with stable volume and transmurality. In T2 maps, hMI was most visible 5 to 7 days postreperfusion with an area under the curve of 0.98 (sensitivity and specificity ≥0.95) relative to T2∗. However, this was not the case with T1 (sensitivity <0.8, across all time points).

CONCLUSIONS

HMI cannot be reliably detected with T1, T2, or T2∗ on 3.0-T CMR immediately after reperfusion. However, T2∗ CMR can be used to diagnose hMI between 24 hours and 7 days postreperfusion. T2 maps at 3.0-T are a strong alternative to T2∗ maps for diagnosing hMI, provided CMR is performed 5 to 7 days postreperfusion. However, diagnosing hMI with T1 is significantly more challenging at 3.0-T compared with both T2∗ and T2.

Intramyocardial Hemorrhage in Patients with Acute Myocardial Infarction Without Reperfusion Therapy: A Prospective Study

Background and Aims

IMH commonly presents in STEMI patients receiving reperfusion therapy and is considered as an ischemic reperfusion injury. However, it is unclear whether IMH occurs in AMI patients without reperfusion therapy.

Methods and Results

We prospectively enrolled 40 patients with STEMI and 41 patients with NSTEMI admitted to the CCU of the Second Xiangya Hospital of Central South University from April 2020 to November 2021, all of whom did not receive reperfusion therapy. In the STEMI group, 16 patients were detected with IMH by CMR. However, in the NSTEMI group, only 3 patients were detected. The incidence of IMH was significantly higher in patients with STEMI than NSTEMI (16/40 vs 3/41, P < 0.001). Among patients with STEMI, the incidence of IMH was not significantly different between patients who underwent primary percutaneous coronary intervention and those who did not (16/40 vs 27/65, P = 0.876). Patients in the spontaneous reperfusion group had a higher incidence of IMH than patients in the non-spontaneous reperfusion group (11/23 vs 5/17, P = 0.240). Similarly, in patients with STEMI who did not receive reperfusion therapy, the incidence of MACE was higher in the IMH-present group than in the IMH-absent group (5/16 vs 2/24, P = 0.063).

Conclusion

The incidence of IMH is comparable in patients with STEMI with or without reperfusion therapy, but considerably higher than that in NSTEMI patients. Patients with STEMI can present with IMH even when infarct-related vessel flow is not restored.

Invasive assessment of coronary microvascular dysfunction and cardiovascular outcomes across the full spectrum of CHD: a meta-analysis

INTRODUCTION AND OBJECTIVES

Coronary microvascular dysfunction (CMD) is highly prevalent and is recognized as an important clinical entity in patients with coronary heart disease (CHD). Nevertheless, the association of CMD with adverse cardiovascular events in the spectrum of CHD has not been systemically quantified.

METHODS

We searched electronic databases for studies on patients with CHD in whom coronary microvascular function was measured invasively, and clinical events were recorded. The primary endpoint was major adverse cardiac events (MACE), and the secondary endpoint was all-cause death. Estimates of effect were calculated using a random-effects model from published risk ratios.

RESULTS

We included 27 studies with 11 404 patients. Patients with CMD assessed by invasive methods had a higher risk of MACE (RR, 2.18; 95%CI, 1.80-2.64; P<.01) and all-cause death (RR, 1.88; 95%CI, 1.55-2.27; P<.01) than those without CMD. There was no significant difference in the impact of CMD on MACE (interaction P value=.95) among different invasive measurement modalities. The magnitude of risk of CMD assessed by invasive measurements for MACE was greater in acute coronary syndrome patients (RR, 2.84, 95%CI, 2.26-3.57; P<.01) than in chronic coronary syndrome patients (RR, 1.77, 95%CI, 1.44-2.18; P<.01) (interaction P value<.01).

CONCLUSIONS

CMD based on invasive measurements was associated with a high incidence of MACE and all-cause death in patients with CHD. The magnitude of risk for cardiovascular events in CMD as assessed by invasive measurements was similar among different methods but varied among CHD populations.

Hemin promotes platelet activation and plasma membrane disintegration regulated by the subtilisin-like proprotein convertase furin

Platelet activation plays a critical role in thrombosis and hemostasis. Several pathophysiological situations lead to hemolysis, resulting in the liberation of free ferric iron-containing hemin. Hemin has been shown to activate platelets and induce thrombo-inflammation. Classical antiplatelet therapy failed to prevent hemin-induced platelet activation. Thus, the aim of the present study was to characterize the mechanism of hemin-induced platelet death (ferroptosis). We evaluated the in vitro effect of hemin on platelet activation, signaling, oxylipins, and plasma membrane destruction using light transmission aggregometry, ex vivo thrombus formation, multiparametric flow cytometry, micro-UHPLC mass spectrometry for oxylipin profiling, and scanning ion conductance microscopy (SICM). We found that hemin induces platelet cell death indicated by increased ROS levels, phosphatidyl serine (PS) exposure, and loss of mitochondrial membrane potential (ΔΨm). Further, hemin causes lipid peroxidation and generation of distinct oxylipins, which strongly affects plasma membrane integrity leading to generation of platelet-derived microvesicles. Interestingly, hemin-dependent platelet death (ferroptosis) is specifically regulated by the subtilisin-like proprotein convertase furin. In summary, platelet undergo a non-apoptotic cell death mediated by furin. Inhibition of furin may offer a therapeutic strategy to control hemin-induced thrombosis and thrombo-inflammation at a site of hemolysis.

Risk factor analysis of microvascular obstruction after percutaneous coronary intervention for ST-segment elevation myocardial infarction

OBJECTIVE

This study aimed to explore the risk factors of microvascular obstruction (MVO) after percutaneous coronary intervention (PCI) in patients with ST-segment elevation myocardial infarction (STEMI).

METHODS

A retrospective analysis was performed on 165 patients with STEMI who successfully underwent emergency PCI and completed cardiac magnetic resonance (CMR) within 1 week after PCI. Total ischemia time (symptom onset to wire, S2W), first medical contact to wire (FMC2W), and door to wire (D2W) were compared with the recommended critical time nodes for STEMI treatment. Left ventricular function was evaluated by CMR cine, and myocardial infarction characteristics and MVO were evaluated by late-gadolinium enhancement (LGE). Binary logistic regression analysis was used to evaluate the effect of delay in treatment of STEMI on the occurrence of MVO after PCI.

RESULTS

In this study, 89 (53.9%) patients with STEMI presented with MVO after emergency PCI. The FMC2W time and S2W time in the MVO (+) group were significantly longer than those in the MVO (-) group (P < 0.05). Compared with the MVO (-) group, the MVO (+) group had larger myocardial infarction size (IS) and lower left ventricular ejection fraction (LVEF) (P < 0.05). Patients with FMC2W time >120 min and S2W time >300 min had greater myocardial IS and MVO than the FMC2W ≤ 120 min and S2W time ≤300 min group, respectively. Logistic regression analysis showed that S2W time >300 min (P = 0.039, OR = 2.756, 95% CI = 1.053-7.213) was an independent predictor of MVO after PCI in patients with STEMI.

CONCLUSION

Shortening the total time of myocardial ischemia and increasing the proportion of early reperfusion therapy can prevent or reduce MVO after PCI.

Post myocardial infarction left ventricular intramyocardial dissecting hematoma penetrated right ventricular outflow tract: a rare complication report

BACKGROUND

Intramyocardial dissecting hematoma (IDH) is a rare mechanical complication following myocardial infarction (MI), and only a few isolated cases have been reported to date. IDH presents with diverse clinical manifestations, often resulting in missed or misdiagnosed cases due to limited physician understanding. The diagnosis and treatment of IDH is a major challenge.

CASE PRESENTATIONS

We report a case of acute extensive anterior MI in a 73-year-old woman, who underwent percutaneous coronary intervention (PCI); the left ventricular intramyocardial dissecting hematoma (LVIDH) penetrated the right ventricular outflow tract (RVOT), resulting in thrombus formation and subsequent RVOT obstruction. Clinically insignificant IDH was detected by transthoracic echocardiography (TTE) at 3 days, 43 days, and 75 days post-PCI, with characteristic changes in the left ventricular wall ultrasound images. This unusual case highlights the important role of continuous transthoracic echocardiography in identifying this rare complication of LVIDH. After a detailed discussion with the patient, the choice between conservative or surgical management of IDH depends on factors such as the size of the hematomae, left ventricular systolic function, and the patient's clinical and haemodynamic status. In this particular case, conservative management was chosen by the patient who declined surgery but unfortunately succumbed to cardiogenic shock.

CONCLUSIONS

This case describes a rare complication of acute myocardial infarction (AMI) and also focuses on the utility of TTE in the diagnosis of this rare complication. Whether LVIDH is treated conservatively or surgically requires careful evaluation to achieve the best prognosis for the patient.

MiRNA Regulates Ferroptosis in Cardiovascular and Cerebrovascular Diseases

Cardiovascular and cerebrovascular diseases (CCVDs) significantly contribute to global mortality and morbidity due to their complex pathogenesis involving multiple biological processes. Ferroptosis is an important physiological process in CCVDs, manifested by an abnormal increase in intracellular iron concentration. MiRNAs, a key class of noncoding RNA molecules, are crucial in regulating CCVDs through pathways like glutathione-glutathione peroxidase 4, glutamate/cystine transport, iron metabolism, lipid metabolism, and other oxidative stress pathways. This article summarizes the progress of miRNAs' regulation on CCVDs, aiming to provide insights for the diagnosis and treatment of CCVDs.

Hypothermia for Cardioprotection in Acute Coronary Syndrome Patients: From Bench to Bedside

Early revascularization for patients with acute myocardial infarction (AMI) is of outmost importance in limiting infarct size and associated complications, as well as for improving long-term survival and outcomes. However, reperfusion itself may further damage the myocardium and increase the infarct size, a condition commonly recognized as myocardial reperfusion injury. Several strategies have been developed for limiting the associated with reperfusion myocardial damage, including hypothermia. Hypothermia has been shown to limit the degree of infarct size increase, when started before reperfusion, in several animal models. Systemic hypothermia, however, failed to show any benefit, due to adverse events and potentially insufficient myocardial cooling. Recently, the novel technique of intracoronary selective hypothermia is being tested, with preclinical and clinical results being of particular interest. Therefore, in this review, we will describe the pathophysiology of myocardial reperfusion injury and the cardioprotective mechanics of hypothermia, report the animal and clinical evidence in both systemic and selective hypothermia and discuss the potential future directions and clinical perspectives in the context of cardioprotection for myocardial reperfusion injury.

Intracoronary thrombolysis in ST-elevation myocardial infarction: a systematic review and meta-analysis

BACKGROUND

Despite restoration of epicardial blood flow in acute ST-elevation myocardial infarction (STEMI), inadequate microcirculatory perfusion is common and portends a poor prognosis. Intracoronary (IC) thrombolytic therapy can reduce microvascular thrombotic burden; however, contemporary studies have produced conflicting outcomes.

OBJECTIVES

This meta-analysis aims to evaluate the efficacy and safety of adjunctive IC thrombolytic therapy at the time of primary percutaneous coronary intervention (PCI) among patients with STEMI.

METHODS

Comprehensive literature search of six electronic databases identified relevant randomised controlled trials. The primary outcome was major adverse cardiac events (MACE). The pooled risk ratio (RR) and weighted mean difference (WMD) with a 95% CI were calculated.

RESULTS

12 studies with 1915 patients were included. IC thrombolysis was associated with a significantly lower incidence of MACE (RR=0.65, 95% CI 0.51 to 0.82, I2=0%, p<0.0004) and improved left ventricular ejection fraction (WMD=1.87; 95% CI 1.07 to 2.67; I2=25%; p<0.0001). Subgroup analysis demonstrated a significant reduction in MACE for trials using non-fibrin (RR=0.39, 95% CI 0.20 to 0.78, I2=0%, p=0.007) and moderately fibrin-specific thrombolytic agents (RR=0.62, 95% CI 0.47 to 0.83, I2=0%, p=0.001). No significant reduction was observed in studies using highly fibrin-specific thrombolytic agents (RR=1.10, 95% CI 0.62 to 1.96, I2=0%, p=0.75). Furthermore, there were no significant differences in mortality (RR=0.91; 95% CI 0.48 to 1.71; I2=0%; p=0.77) or bleeding events (major bleeding, RR=1.24; 95% CI 0.47 to 3.28; I2=0%; p=0.67; minor bleeding, RR=1.47; 95% CI 0.90 to 2.40; I2=0%; p=0.12).

CONCLUSION

Adjunctive IC thrombolysis at the time of primary PCI in patients with STEMI improves clinical and myocardial perfusion parameters without an increased rate of bleeding. Further research is needed to optimise the selection of thrombolytic agents and treatment protocols.

Cardiac-derived extracellular vesicles improve mitochondrial function to protect the heart against ischemia/reperfusion injury by delivering ATP5a1

BACKGROUND

Numerous studies have confirmed the involvement of extracellular vesicles (EVs) in various physiological processes, including cellular death and tissue damage. Recently, we reported that EVs derived from ischemia-reperfusion heart exacerbate cardiac injury. However, the role of EVs from healthy heart tissue (heart-derived EVs, or cEVs) on myocardial ischemia-reperfusion (MI/R) injury remains unclear.

RESULTS

Here, we demonstrated that intramyocardial administration of cEVs significantly enhanced cardiac function and reduced cardiac damage in murine MI/R injury models. cEVs treatment effectively inhibited ferroptosis and maintained mitochondrial homeostasis in cardiomyocytes subjected to ischemia-reperfusion injury. Further results revealed that cEVs can transfer ATP5a1 into cardiomyocytes, thereby suppressing mitochondrial ROS production, alleviating mitochondrial damage, and inhibiting cardiomyocyte ferroptosis. Knockdown of ATP5a1 abolished the protective effects of cEVs. Furthermore, we found that the majority of cEVs are derived from cardiomyocytes, and ATP5a1 in cEVs primarily originates from cardiomyocytes of the healthy murine heart. Moreover, we demonstrated that adipose-derived stem cells (ADSC)-derived EVs with ATP5a1 overexpression showed much better efficacy on the therapy of MI/R injury compared to control ADSC-derived EVs.

CONCLUSIONS

These findings emphasized the protective role of cEVs in cardiac injury and highlighted the therapeutic potential of targeting ATP5a1 as an important approach for managing myocardial damage induced by MI/R injury.

Paintable Decellularized-ECM Hydrogel for Preventing Cardiac Tissue Damage

The tissue-specific heart decellularized extracellular matrix (hdECM) demonstrates a variety of therapeutic advantages, including fibrosis reduction and angiogenesis. Consequently, recent research for myocardial infarction (MI) therapy has utilized hdECM with various delivery techniques, such as injection or patch implantation. In this study, a novel approach for hdECM delivery using a wet adhesive paintable hydrogel is proposed. The hdECM-containing paintable hydrogel (pdHA_t) is simply applied, with no theoretical limit to the size or shape, making it highly beneficial for scale-up. Additionally, pdHA_t exhibits robust adhesion to the epicardium, with a minimal swelling ratio and sufficient adhesion strength for MI treatment when applied to the rat MI model. Moreover, the adhesiveness of pdHA_t can be easily washed off to prevent undesired adhesion with nearby organs, such as the rib cages and lungs, which can result in stenosis. During the 28 days of in vivo analysis, the pdHA_t not only facilitates functional regeneration by reducing ventricular wall thinning but also promotes neo-vascularization in the MI region. In conclusion, the pdHA_t presents a promising strategy for MI treatment and cardiac tissue regeneration, offering the potential for improved patient outcomes and enhanced cardiac function post-MI.

Deciphering the Enigma of Intramyocardial Hemorrhage Following Reperfusion Therapy in Acute ST-Segment Elevation Myocardial Infarction: A Comprehensive Exploration from Mechanisms to Therapeutic Strategies

Acute ST-segment elevation myocardial infarction (STEMI) is a formidable challenge in cardiovascular medicine, demanding advanced reperfusion strategies such as emergency percutaneous coronary intervention. While successful revascularization is pivotal, the persistent "no-reflow" phenomenon remains a clinical hurdle, often intertwined with microvascular dysfunction. Within this intricate scenario, the emergence of intramyocardial hemorrhage (IMH) has garnered attention as a significant contributor. This review offers a detailed exploration of the multifaceted relationship between IMH and the "no-reflow" phenomenon, delving into the mechanisms governing IMH occurrence, state-of-the-art diagnostic modalities, predictive factors, clinical implications, and the evolving landscape of preventive and therapeutic strategies. The nuanced examination aims to deepen our comprehension of IMH, providing a foundation for the identification of innovative therapeutic avenues and enhanced clinical outcomes for STEMI patients.

Non-electrocardiogram-gated, free-breathing, off-resonance reduced, high-resolution, whole-heart myocardial T2 * mapping at 3 T within 5 min

PURPOSE

Widely used conventional 2D T2 * approaches that are based on breath-held, electrocardiogram (ECG)-gated, multi-gradient-echo sequences are prone to motion artifacts in the presence of incomplete breath holding or arrhythmias, which is common in cardiac patients. To address these limitations, a 3D, non-ECG-gated, free-breathing T2 * technique that enables rapid whole-heart coverage was developed and validated.

METHODS

A continuous random Gaussian 3D k-space sampling was implemented using a low-rank tensor framework for motion-resolved 3D T2 * imaging. This approach was tested in healthy human volunteers and in swine before and after intravenous administration of ferumoxytol.

RESULTS

Spatial-resolution matched T2 * images were acquired with 2-3-fold reduction in scan time using the proposed T2 * mapping approach relative to conventional T2 * mapping. Compared with the conventional approach, T2 * images acquired with the proposed method demonstrated reduced off-resonance and flow artifacts, leading to higher image quality and lower coefficient of variation in T2 *-weighted images of the myocardium of swine and humans. Mean myocardial T2 * values determined using the proposed and conventional approaches were highly correlated and showed minimal bias.

CONCLUSION

The proposed non-ECG-gated, free-breathing, 3D T2 * imaging approach can be performed within 5 min or less. It can overcome critical image artifacts from undesirable cardiac and respiratory motion and bulk off-resonance shifts at the heart-lung interface. The proposed approach is expected to facilitate faster and improved cardiac T2 * mapping in those with limited breath-holding capacity or arrhythmias.

An enhanced cardio-protective effect of nanoparticles loaded with active components from Polygonum orientale L. against isoproterenol-induced myocardial ischemia in rats

In this study, nanoparticles loaded with active components from Polygonum orientale L. (PO), a traditional Chinese herb known for its anti-myocardial ischemic properties, were investigated for cardio-protective properties. Specifically, OVQ-Nanoparticles (OVQ-NPs) with Orientin (Ori), Vitexin (Vit), and Quercetin (Que) was obtained by double emulsion-solvent evaporation method. The OVQ-NPs exhibited a spherical shape, with a uniform size distribution of 136.77 ± 3.88 nm and a stable ζ-potential of -13.40 ± 2.24 mV. Notably, these nanoparticles exhibited a favorable sustained-release characteristic, resulting in an extended circulation time within the living organism. Consequently, the administration of these nanoparticles resulted in significant improvements in electrocardiograms and heart mass index of myocardial ischemic rats induced by isoproterenol, as well as decreased serum levels of CK, LDH, and AST. Furthermore, the results of histopathological examination, such as H&E staining and TUNEL staining, confirmed a reduced level of cardiac tissue pathology and apoptosis. Moreover, the quantification of biochemical indicators (SOD, MDA, GSH, NO, TNF-α, and IL-6) demonstrated that OVQ-NPs effectively mitigated myocardial ischemia by regulating oxidative stress and inflammatory pathways. In conclusion, OVQ-NPs demonstrate promising therapeutic potential as an intervention for myocardial ischemia, providing a new perspective on traditional Chinese medicine treatment in this area.

Mesenchymal stromal cells for improvement of cardiac function following acute myocardial infarction: a matter of timing

Acute myocardial infarction (AMI) is the leading cause of cardiovascular death and remains the most common cause of heart failure. Reopening of the occluded artery, i.e., reperfusion, is the only way to save the myocardium. However, the expected benefits of reducing infarct size are disappointing due to the reperfusion paradox, which also induces specific cell death. These ischemia-reperfusion (I/R) lesions can account for up to 50% of final infarct size, a major determinant for both mortality and the risk of heart failure (morbidity). In this review, we provide a detailed description of the cell death and inflammation mechanisms as features of I/R injury and cardioprotective strategies such as ischemic postconditioning as well as their underlying mechanisms. Due to their biological properties, the use of mesenchymal stromal/stem cells (MSCs) has been considered a potential therapeutic approach in AMI. Despite promising results and evidence of safety in preclinical studies using MSCs, the effects reported in clinical trials are not conclusive and even inconsistent. These discrepancies were attributed to many parameters such as donor age, in vitro culture, and storage time as well as injection time window after AMI, which alter MSC therapeutic properties. In the context of AMI, future directions will be to generate MSCs with enhanced properties to limit cell death in myocardial tissue and thereby reduce infarct size and improve the healing phase to increase postinfarct myocardial performance.

A nomogram model for predicting intramyocardial hemorrhage post-PCI based on SYNTAX score and clinical features

OBJECTIVE

The aim of this study is to develop a nomogram model for predicting the occurrence of intramyocardial hemorrhage (IMH) in patients with Acute Myocardial Infarction (AMI) following Percutaneous Coronary Intervention (PCI). The model is constructed utilizing clinical data and the SYNTAX Score (SS), and its predictive value is thoroughly evaluated.

METHODS

A retrospective study was conducted, including 216 patients with AMI who underwent Cardiac Magnetic Resonance (CMR) within a week post-PCI. Clinical data were collected for all patients, and their SS were calculated based on coronary angiography results. Based on the presence or absence of IMH as indicated by CMR, patients were categorized into two groups: the IMH group (109 patients) and the non-IMH group (107 patients). The patients were randomly divided in a 7:3 ratio into a training set (151 patients) and a validation set (65 patients). A nomogram model was constructed using univariate and multivariate logistic regression analyses. The predictive capability of the model was assessed using Receiver Operating Characteristic (ROC) curve analysis, comparing the predictive value based on the area under the ROC curve (AUC).

RESULTS

In the training set, IMH post-PCI was observed in 78 AMI patients on CMR, while 73 did not show IMH. Variables with a significance level of P < 0.05 were screened using univariate logistic regression analysis. Twelve indicators were selected for multivariate logistic regression analysis: heart rate, diastolic blood pressure, ST segment elevation on electrocardiogram, culprit vessel, symptom onset to reperfusion time, C-reactive protein, aspartate aminotransferase, lactate dehydrogenase, creatine kinase, creatine kinase-MB, high-sensitivity troponin T (HS-TnT), and SYNTAX Score. Based on multivariate logistic regression results, two independent predictive factors were identified: HS-TnT (Odds Ratio [OR] = 1.61, 95% Confidence Interval [CI]: 1.21-2.25, P = 0.003) and SS (OR = 2.54, 95% CI: 1.42-4.90, P = 0.003). Consequently, a nomogram model was constructed based on these findings. The AUC of the nomogram model in the training set was 0.893 (95% CI: 0.840-0.946), and in the validation set, it was 0.910 (95% CI: 0.823-0.970). Good consistency and accuracy of the model were demonstrated by calibration and decision curve analysis.

CONCLUSION

The nomogram model, constructed utilizing HS-TnT and SS, demonstrates accurate predictive capability for the risk of IMH post-PCI in patients with AMI. This model offers significant guidance and theoretical support for the clinical diagnosis and treatment of these patients.

Intramyocardial Hemorrhage Leads to Higher MACE Rate by Increasing Myocardial Infarction Volume in Patients with STEMI

Background and Aims

Whether IMH can directly cause persistent myocardial necrosis after reperfusion therapy in STEMI patients is still unclear. We conducted a prospective study to compare the cardiovascular parameters in patients with STEMI with and without IMH to explore the potential correlations between IMH and poor outcomes.

Methods and Results

We prospectively enrolled 65 consecutive patients with newly diagnosed STEMI admitted to the CCU of the Second Xiangya Hospital of Central South University between April 2019 and November 2021, all of whom underwent primary PCI. Of these, 38 (58.5%) and 27 (41.5%) patients were in the IMH-absent and IMH-present groups, respectively. At a mean time of 5-7 days after reperfusion therapy, the volume of MI measured using LGE sequence was larger in STEMI patients with IMH than in patients without IMH (34.2 ± 12.7 cm3 vs 21.1 ± 13.1 cm3, P<0.001). HsTNT levels were significantly higher in the IMH-present group than in the IMH-absent [2500.0 (1681.5-4307.0) pg/mL vs 1710.0 (203.0-3363.5) pg/mL, P=0.021] group during hospitalization. The LVEF measured using CMR in the IMH-present group was lower than that in the IMH-absent group (30.7 ± 9.8% vs 42.3 ± 11.0%, P < 0.001). The rate of MACE at 12 months in IMH-present group was significantly higher than in the IMH-absent group (9/27 VS 2/38, P = 0.012).

Conclusion

IMH can lead to further expansion of MI volumes in patients with STEMI, resulting in lower LVEF and higher MACE rate in the post-discharge follow-up.

Characterization of quantitative susceptibility mapping in the left ventricular myocardium

BACKGROUND

Myocardial quantitative susceptibility mapping (QSM) may offer better specificity to iron than conventional T2* imaging in the assessment of cardiac diseases, including intra-myocardial hemorrhage. However, the precision and repeatability of cardiac QSM have not yet been characterized. The aim of this study is to characterize these key metrics in a healthy volunteer cohort and show the feasibility of the method in patients.

METHODS

Free breathing respiratory-navigated multi-echo 3D gradient echo images were acquired, from which QSM maps were reconstructed using the Morphology Enhanced Dipole Inversion toolbox. This technique was first evaluated in a susceptibility phantom containing tubes with known concentrations of gadolinium. In vivo characterization of myocardial QSM was then performed in a cohort of 10 healthy volunteers where each subject was scanned twice. Mean segment susceptibility, precision (standard deviation of voxel magnetic susceptibilities within one segment), and repeatability (absolute difference in segment mean susceptibility between repeats) of QSM were calculated for each American Heart Association (AHA) myocardial segment. Finally, the feasibility of the method was shown in 10 patients, including four with hemorrhagic infarcts.

RESULTS

The phantom experiment showed a strong linear relationship between measured and predicted susceptibility shifts (R2 > 0.99). For the healthy volunteer cohort, AHA segment analysis showed the mean segment susceptibility was 0.00 ± 0.02 ppm, the mean precision was 0.05 ± 0.04 ppm, and the mean repeatability was 0.02 ± 0.02 ppm. Cardiac QSM was successfully performed in all patients. Focal iron deposits were successfully visualized in the patients with hemorrhagic myocardial infarctions.

CONCLUSION

The precision and repeatability of cardiac QSM were successfully characterized in phantom and in vivo experiments. The feasibility of the technique was also successfully demonstrated in patients. While challenges still remain, further clinical evaluation of the technique is now warranted.

TRIAL REGISTRATION

This work does not report on a health care intervention.

Myocardial ischemia/reperfusion: Translational pathophysiology of ischemic heart disease

Ischemic heart disease is the greatest health burden and most frequent cause of death worldwide. Myocardial ischemia/reperfusion is the pathophysiological substrate of ischemic heart disease. Improvements in prevention and treatment of ischemic heart disease have reduced mortality in developed countries over the last decades, but further progress is now stagnant, and morbidity and mortality from ischemic heart disease in developing countries are increasing. Significant problems remain to be resolved and require a better pathophysiological understanding. The present review attempts to briefly summarize the state of the art in myocardial ischemia/reperfusion research, with a view on both its coronary vascular and myocardial aspects, and to define the cutting edges where further mechanistic knowledge is needed to facilitate translation to clinical practice.

On the loss of image contrast in double-inversion-recovery prepared T2* MRI of Intramyocardial hemorrhage

PURPOSE

Studies have shown that double-inversion-recovery (DIR) prepared dark-blood T2*-weighted images result in lower SNR, CNR and diagnostic accuracy for intramyocardial hemorrhage (IMH) detection compared to non-DIR-prepared (bright-blood) T2*-weighted images; however, the mechanism contributing to this observation has not been investigated and explained in detail. This work tests the hypothesis that the loss of SNR on dark-blood cardiac T2*-weighted images of IMH stems from spin-relaxation during the long RF pulses in double inversion preparation, as a result, compromising image contrast for intramyocardial hemorrhage detection.

METHODS

Phantom and in-vivo animal studies were performed to test the hypothesis of the study. An agar phantom was imaged with multi-gradient-echo T2* imaging protocols with and without double-inversion-recovery (DIR) preparation. Image acquisitions were placed at different delay times (TD) after DIR preparation. SNR, T2* and Coefficient of Variation (COV) were measured and compared between DIR-prepared and non-DIR-prepared images. Canines with hemorrhagic myocardial infarctions were scanned at 3.0 T with DIR-prepared (dark-blood) and non-DIR-prepared (bright-blood) T2* imaging protocols. DIR-prepared T2* images were acquired with short, medium, and long delay times (TD). SNR, CNR, intramyocardial hemorrhage (IMH) extent, T2* and COV were measured and compared between DIR-prepared T2* images with short, medium, and long delay times (TD) to non-DIR-prepared bright-blood T2* images.

RESULTS

Phantom studies confirmed the hypothesis that the SNR loss on DIR-prepared T2* images originated from signal loss during DIR preparation. SNR followed T1 recovery curve with increased delay times (TD) indicating that SNR can be recovered with longer time delay between DIR and image acquisition. Myocardial T2* values were not affected by DIR preparation but COV of T2* was elevated. Animal studies supported the hypothesis and showed that DIR-prepared T2* images with insufficient delay time (TD) had impaired sensitivity for IMH detection due to lower SNR and CNR, and higher COV.

CONCLUSION

We conclude that lower SNR and CNR on DIR-prepared T2* images originate from signal loss during DIR preparation and insufficient recovery between DIR preparation and image acquisition. Although, the impaired sensitivity can be recovered by extending delay time (TD), it will extend the scan time. Bright-blood T2* imaging protocols should remain the optimal choice for assessment of intramyocardial hemorrhage. DIR-prepared dark-blood T2* imaging protocols should be performed with extra attention on image signal-to-noise ratio when used for intramyocardial hemorrhage detection.

Prospects for Precision Medicine in Acute Myocardial Infarction: Patient-Level Insights into Myocardial Injury and Repair

The past decade has seen a marked expansion in the understanding of the pathobiology of acute myocardial infarction and the systemic inflammatory response that it elicits. At the same time, a portfolio of tools has emerged to characterise some of these processes in vivo. However, in clinical practice, key decision making still largely relies on assessment built around the timing of the onset of chest pain, features on electrocardiograms and measurements of plasma troponin. Better understanding the heterogeneity of myocardial injury and patient-level responses should provide new opportunities for diagnostic stratification to enable the delivery of more rational therapies. Characterisation of the myocardium using emerging imaging techniques such as the T1, T2 and T2* mapping techniques can provide enhanced assessments of myocardial statuses. Physiological measures, which include microcirculatory resistance and coronary flow reserve, have been shown to predict outcomes in AMI and can be used to inform treatment selection. Functionally informative blood biomarkers, including cellular transcriptomics; microRNAs; extracellular vesicle analyses and soluble markers, all give insights into the nature and timing of the innate immune response and its regulation in acute MI. The integration of these and other emerging tools will be key to developing a fuller understanding of the patient-level processes of myocardial injury and repair and should fuel new possibilities for rational therapeutic intervention.

Curcumin analogue C66 ameliorates mouse cardiac dysfunction and structural disorders after acute myocardial infarction via suppressing JNK activation

Myocardial infarction contributes to the development of cardiovascular disease, and leads to severe inflammation and health hazards. Our previous studies identified C66, a novel curcumin analogue, had pharmacological benefits in suppressing tissue inflammation. Therefore, the present study hypothesized C66 might improve cardiac function and attenuate structural remodeling after acute myocardial infarction. Administration of 5 mg/kg C66 for 4-week significantly improved cardiac function and decreased infarct size after myocardial infarction. C66 also effectively reduced cardiac pathological hypertrophy and fibrosis in non-infarct area. In vitro H9C2 cardiomyocytes, C66 also exerted the pharmacological benefits of anti-inflammatory and anti-apoptosis under hypoxic conditions Mechanistically, C66 inhibited cardiac inflammation and cardiomyocyte apoptosis by targeting on JNK phosphorylation, whereas replenishment of JNK activation abolished the cardioprotective benefits of C66 treatment. Taken together, curcumin analogue C66 inhibited the activation of JNK signaling, and possessed pharmacological benefits in alleviating myocardial infarction-induced cardiac dysfunction and pathological tissue injuries.

SGLT2 inhibitor dapagliflozin alleviates intramyocardial hemorrhage and adverse ventricular remodeling via suppressing hepcidin in myocardial ischemia-reperfusion injury

Intramyocardial hemorrhage (IMH), a reperfusion therapy-associated complication, is the extravasation of red blood cells caused by severe microvascular injury. IMH is an independent predictor of adverse ventricular remodeling (AVR) after acute myocardial infarction (AMI). Hepcidin, a major regulator of iron uptake and systemic distribution, is a key factor affecting AVR. However, the role of cardiac hepcidin in the development of IMH has not been completely elucidated. This study aimed to explore if sodium-dependent glucose co-transporter 2 inhibitor (SGLT2i) exerts therapeutic effects on IMH and AVR by suppressing hepcidin and to elucidate the underlying mechanisms. SGLT2i alleviated IMH and AVR in the ischemia-reperfusion injury (IRI) mouse model. Additionally, SGLT2i downregulated the cardiac levels of hepcidin in IRI mice, suppressed M1-type macrophage polarization, and promoted M2-type macrophage polarization. The effects of hepcidin knockdown on macrophage polarization were similar to those of SGLT2i in RAW264.7 cells. SGLT2i treatment or hepcidin knockdown inhibited the expression of MMP9, an inducer of IMH and AVR, in RAW264.7 cells. Regulation of macrophage polarization and reduction of MMP9 expression by SGLT2i and hepcidin knockdown is achieved through activation of pSTAT3. In conclusion, this study demonstrated that SGLT2i alleviated IMH and AVR by regulating macrophage polarization. The potential mechanism through which SGLT2i exerted its therapeutic effect seems to involve the downregulation of MMP9 via the hepcidin-STAT3 pathway.

Coronary microvascular dysfunction: A review of recent progress and clinical implications

The coronary microcirculation plays a cardinal role in regulating coronary blood flow to meet the changing metabolic demands of the myocardium. Coronary microvascular dysfunction (CMD) refers to structural and functional remodeling of the coronary microcirculation. CMD plays a role in the pathogenesis of obstructive and non-obstructive coronary syndromes as well as myocardial diseases, including heart failure with preserved ejection fraction (HFpEF). Despite recent diagnostic advancements, CMD is often under-appreciated in clinical practice, and may allow for the development of novel therapeutic targets. This review explores the diagnosis and pathogenic role of CMD across a range of cardiovascular diseases, its prognostic significance, and the current therapeutic landscape.

Imatinib attenuates reperfusion injury in a rat model of acute myocardial infarction

Following an acute myocardial infarction, reperfusion of an occluded coronary artery is often accompanied by microvascular injury, leading to worse long-term prognosis. Experimental studies have revealed the potential of tyrosine-kinase inhibitor imatinib to reduce vascular leakage in various organs. Here, we examined the potential of imatinib to attenuate microvascular injury in a rat model of myocardial reperfusion injury. Isolated male Wistar rat hearts (n = 20) in a Langendorff system and male Wistar rats (n = 37) in an in vivo model were randomly assigned to imatinib or placebo and subjected to ischaemia and reperfusion. Evans-blue/Thioflavin-S/TTC staining and Cardiac Magnetic Resonance Imaging were performed to assess the extent of reperfusion injury. Subsequently, in vivo hearts were perfused ex vivo with a vascular leakage tracer and fluorescence and electron microscopy were performed. In isolated rat hearts, imatinib reduced global infarct size, improved end-diastolic pressure, and improved rate pressure product recovery compared to placebo. In vivo, imatinib reduced no-reflow and infarct size with no difference between imatinib and placebo for global cardiac function. In addition, imatinib showed lower vascular resistance, higher coronary flow, and less microvascular leakage in the affected myocardium. At the ultrastructural level, imatinib showed higher preserved microvascular integrity compared to placebo. We provide evidence that low-dose imatinib can reduce microvascular injury and accompanying myocardial infarct size in a rat model of acute myocardial infarction. These data warrant future work to examine the potential of imatinib to reduce reperfusion injury in patients with acute myocardial infarction.

Effect of ticagrelor and prasugrel on remote myocardial inflammation in patients with acute myocardial infarction with ST-elevation: a CMR T1 and T2 mapping study

PURPOSE

Acute myocardial ischaemia triggers a non-specific inflammatory response of remote myocardium through the increase of plasma concentrations of acute-phase proteins, which causes myocardial oedema. As ticagrelor has been shown to significantly decrease circulating levels of several pro-inflammatory cytokines in patients after acute myocardial infarction with ST-elevation (STEMI), we sought to investigate a potential suppressive effect of ticagrelor over prasugrel on cardiac magnetic resonance (CMR) T1 and T2 values in remote myocardium.

METHODS

Ninety STEMI patients were prospectively included and randomised to receive either ticagrelor or prasugrel maintenance treatment after successful primary percutaneous coronary intervention. Patients underwent CMR after 2-7 days. The protocol included long and short axis cine imaging, T1 mapping, T2 mapping and late gadolinium enhancement imaging.

RESULTS

After excluding 30 patients due to either missing images or insufficient quality of the T1 or T2 maps, 60 patients were included in our analysis. Of those, 29 patients were randomised to the ticagrelor group and 31 patients to the prasugrel group. In the remote myocardium, T1 values did not differ between groups (931.3 [919.4-950.4] ms for ticagrelor vs. 932.6 [915.5-949.2] ms for prasugrel (p = 0.94)), nor did the T2 values (53.8 ± 4.6 ms for ticagrelor vs. 53.7 ± 4.7 ms for prasugrel (p = 0.86)). Also, in the infarcted myocardium, T1 and T2 values did not differ between groups.

CONCLUSION

In revascularised STEMI patients, ticagrelor maintenance therapy did not show superiority over prasugrel in preventing early remote myocardial inflammation as assessed by CMR T1 and T2 mapping.

The Dynamic Relationship Between Invasive Microvascular Function and Microvascular Injury Indicators, and Their Association With Left Ventricular Function and Infarct Size at 1-Month After Reperfused ST-Segment-Elevation Myocardial Infarction

BACKGROUND

The invasive microvascular function indices, coronary flow reserve (CFR) and the index of microcirculatory resistance (IMR), exhibit a dynamic pattern after ST-segment-elevation myocardial infarction. The effects of microvascular injury on the evolution of the microvascular function and the prognostic significance of the evolution of microvascular function are unknown. We investigated the relationship between the temporal changes of CFR and IMR, and cardiovascular magnetic resonance-derived microvascular injury characteristics in reperfused ST-segment-elevation myocardial infarction patients, and their association with 1-month left ventricular ejection fraction and infarct size (IS).

METHODS

In 109 ST-segment-elevation myocardial infarction patients who underwent angiography for primary percutaneous coronary intervention (PPCI) and at 1-month follow-up, invasive assessment of CFR and IMR were performed in the culprit artery during both procedures. Cardiovascular magnetic resonance was performed 2 to 7 days after PPCI and at 1 month and provided assessment of left ventricular ejection fraction, IS, microvascular obstruction, and intramyocardial hemorrhage.

RESULTS

CFR and IMR significantly changed over 1 month (both, P<0.001). The absolute IMR change over 1 month (ΔIMR) showed association with both microvascular obstruction and intramyocardial hemorrhage presence (both, P=0.01). ΔIMR differed between patients with/without microvascular obstruction (P=0.02) and with/without intramyocardial hemorrhage (P=0.04) but not ΔCFR for both. ΔIMR demonstrated association with both left ventricular ejection fraction and IS at 1 month (P<0.001, P=0.001, respectively), but not ΔCFR for both. Receiver-operating characteristics curve analysis of ΔIMR showed a larger area under the curve than post-PPCI CFR and IMR, and ΔCFR to be associated with both 1-month left ventricular ejection fraction >50% and extensive IS (the highest quartile).

CONCLUSIONS

In reperfused ST-segment-elevation myocardial infarction patients, CFR and IMR significantly improved 1 month after PPCI; the temporal change in IMR is closely related to the presence/absence of microvascular damage and IS. ΔIMR exhibits a stronger association for 1-month functional outcome than post-PPCI CFR, IMR, or ΔCFR.

Quantitative susceptibility mapping (QSM) of the cardiovascular system: challenges and perspectives

Quantitative susceptibility mapping (QSM) is a powerful, non-invasive, magnetic resonance imaging (MRI) technique that relies on measurement of magnetic susceptibility. So far, QSM has been employed mostly to study neurological disorders characterized by iron accumulation, such as Parkinson's and Alzheimer's diseases. Nonetheless, QSM allows mapping key indicators of cardiac disease such as blood oxygenation and myocardial iron content. For this reason, the application of QSM offers an unprecedented opportunity to gain a better understanding of the pathophysiological changes associated with cardiovascular disease and to monitor their evolution and response to treatment. Recent studies on cardiovascular QSM have shown the feasibility of a non-invasive assessment of blood oxygenation, myocardial iron content and myocardial fibre orientation, as well as carotid plaque composition. Significant technical challenges remain, the most evident of which are related to cardiac and respiratory motion, blood flow, chemical shift effects and susceptibility artefacts. Significant work is ongoing to overcome these challenges and integrate the QSM technique into clinical practice in the cardiovascular field.

Conservatively treated intramyocardial dissecting haematoma of the interventricular septum as a rare complication of acute myocardial infarction: a case report

Background

Intramyocardial dissecting haematoma (IDH) is a rare and potentially life-threatening complication of acute coronary syndrome. So far only isolated case reports and case series have been published.

Case summary

We report the case of a late presenting myocardial infarction (MI) complicated by IDH of the ventricular septum, following a successful percutaneous coronary intervention (PCI). The clinically inapparent septal mass was discovered during the routine transthoracic echocardiography and the final diagnosis of haematoma was made by magnetic resonance imaging. The patient remained clinically stable, and septal mass on repeated echocardiography showed gradual regression.

Discussion

This report suggests that IDH can spontaneously resolve without surgical intervention. An urgent echocardiogram should be used to assess the vitality of the myocardial tissue, especially with late presenting MI with deep Q-waves on the electrocardiogram strip. Conservative treatment in haemodynamically stable patients with IDH following MI and PCI is a feasible solution.

Gradual Versus Abrupt Reperfusion During Primary Percutaneous Coronary Interventions in ST‐Segment–Elevation Myocardial Infarction (GUARD)

Background

Intramyocardial edema and hemorrhage are key pathological mechanisms in the development of reperfusion‐related microvascular damage in ST‐segment–elevation myocardial infarction. These processes may be facilitated by abrupt restoration of intracoronary pressure and flow triggered by primary percutaneous coronary intervention. We investigated whether pressure‐controlled reperfusion via gradual reopening of the infarct‐related artery may limit microvascular injury in patients undergoing primary percutaneous coronary intervention.

Methods and Results

A total of 83 patients with ST‐segment–elevation myocardial infarction were assessed for eligibility and 53 who did not meet inclusion criteria were excluded. The remaining 30 patients with totally occluded infarct‐related artery were randomized to the pressure‐controlled reperfusion with delayed stenting (PCRDS) group (n=15) or standard primary percutaneous coronary intervention with immediate stenting (IS) group (n=15) (intention‐to‐treat population). Data from 5 patients in each arm were unsuitable to be included in the final analysis. Finally, 20 patients undergoing primary percutaneous coronary intervention who were randomly assigned to either IS (n=10) or PCRDS (n=10) were included. In the PCRDS arm, a 1.5‐mm balloon was used to achieve initial reperfusion with thrombolysis in myocardial infarction grade 3 flow and, subsequently, to control distal intracoronary pressure over a 30‐minute monitoring period (MP) until stenting was performed. In both study groups, continuous assessment of coronary hemodynamics with intracoronary pressure and Doppler flow velocity was performed, with a final measurement of zero flow pressure (primary end point of the study) at the end of a 60‐minute MP. There were no complications associated with IS or PCRDS. PCRDS effectively led to lower distal intracoronary pressures than IS over 30 minutes after reperfusion (71.2±9.37 mm Hg versus 90.13±12.09 mm Hg, P =0.001). Significant differences were noted between study arms in the microcirculatory response over MP. Microvascular perfusion progressively deteriorated in the IS group and at the end of MP, and hyperemic microvascular resistance was significantly higher in the IS arm as compared with the PCDRS arm (2.83±0.56 mm Hg.s.cm −1 versus 1.83±0.53 mm Hg.s.cm −1 , P =0.001). The primary end point (zero flow pressure) was significantly lower in the PCRDS group than in the IS group (41.46±17.85 mm Hg versus 76.87±21.34 mm Hg, P =0.001). In the whole study group (n=20), reperfusion pressures measured at predefined stages in the early reperfusion period showed robust associations with zero flow pressure values measured at the end of the 1‐hour MP (immediately after reperfusion: r =0.782, P <0.001; at the 10th minute: r =0.796, P <0.001; and at the 20th minute: r =0.702, P =0.001) and peak creatine kinase MB level (immediately after reperfusion: r =0.653, P =0.002; at the 10th minute: r =0.597, P =0.007; and at the 20th minute: r =0.538, P =0.017). Enzymatic myocardial infarction size was lower in the PCRDS group than in the IS group with peak troponin T (5395±2991 ng/mL versus 8874±1927 ng/mL, P =0.006) and creatine kinase MB (163.6±93.4 IU/L versus 542.2±227.4 IU/L, P <0.001).

Conclusions

In patients with ST‐segment–elevation myocardial infarction, pressure‐controlled reperfusion of the culprit vessel by means of gradual reopening of the occluded infarct‐related artery (PCRDS) led to better‐preserved coronary microvascular integrity and smaller myocardial infarction size, without an increase in procedural complications, compared with IS.

Registration

URL: https://www.clinicaltrials.gov ; Unique identifier: NCT02732080.

Prevalence and Significance of Impaired Microvascular Tissue Reperfusion Despite Macrovascular Angiographic Reperfusion (No-Reflow)

BACKGROUND AND OBJECTIVES

The relevance of impaired microvascular tissue-level reperfusion despite complete upstream macrovascular angiographic reperfusion (no-reflow) in human stroke remains controversial. We investigated the prevalence and clinical-radiologic features of this phenomenon and its associations with outcomes in 3 international randomized controlled thrombectomy trials with prespecified follow-up perfusion imaging.

METHODS

In a pooled analysis of the Extending the Time for Thrombolysis in Emergency Neurological Deficits-Intra-Arterial (EXTEND-IA; ClinicalTrials.gov NCT01492725), Tenecteplase Versus Alteplase Before Endovascular Therapy for Ischemic Stroke (EXTEND-IA TNK; NCT02388061), and Determining the Optimal Dose of Tenecteplase Before Endovascular Therapy for Ischaemic Stroke (EXTEND-IA TNK Part 2; NCT03340493) trials, patients undergoing thrombectomy with final angiographic expanded Treatment in Cerebral Infarction score of 2c to 3 score for anterior circulation large vessel occlusion and 24-hour follow-up CT or MRI perfusion imaging were included. No-reflow was defined as regions of visually demonstrable persistent hypoperfusion on relative cerebral blood volume or flow maps within the infarct and verified quantitatively by >15% asymmetry compared to a mirror homolog in the absence of carotid stenosis or reocclusion.

RESULTS

Regions of no-reflow were identified in 33 of 130 patients (25.3%), encompassed a median of 60.2% (interquartile range 47.8%-70.7%) of the infarct volume, and involved both subcortical (n = 26 of 33, 78.8%) and cortical (n = 10 of 33, 30.3%) regions. Patients with no-reflow had a median 25.2% (interquartile range 16.4%-32.2%, p < 0.00001) relative cerebral blood volume interside reduction and 19.1% (interquartile range 3.9%-28.3%, p = 0.00011) relative cerebral blood flow reduction but similar mean transit time (median -3.3%, interquartile range -11.9% to 24.4%, p = 0.24) within the infarcted region. Baseline characteristics were similar between patients with and those without no-reflow. The presence of no-reflow was associated with hemorrhagic transformation (adjusted odds ratio [aOR] 1.79, 95% confidence interval [CI] 2.32-15.57, p = 0.0002), greater infarct growth (β = 11.00, 95% CI 5.22-16.78, p = 0.00027), reduced NIH Stroke Scale score improvement at 24 hours (β = -4.06, 95% CI 6.78-1.34, p = 0.004) and being dependent or dead at 90 days as assessed by the modified Rankin Scale (aOR 3.72, 95% CI 1.35-10.20, p = 0.011) in multivariable analysis.

DISCUSSION

Cerebral no-reflow in humans is common, can be detected by its characteristic perfusion imaging profile using readily available sequences in the clinical setting, and is associated with posttreatment complications and being dependent or dead. Further studies evaluating the role of no-reflow in secondary injury after angiographic reperfusion are warranted.

CLASSIFICATION OF EVIDENCE

This study provides Class II evidence that cerebral no-reflow on CT/MRI perfusion imaging at 24 hours is associated with posttreatment complications and poor 3-month functional outcome.

Intramyocardial Hemorrhage and the "Wave Front" of Reperfusion Injury Compromising Myocardial Salvage

BACKGROUND

Reperfusion therapy for acute myocardial infarction (MI) is lifesaving. However, the benefit of reperfusion therapy can be paradoxically diminished by reperfusion injury, which can increase MI size.

OBJECTIVES

Hemorrhage is known to occur in reperfused MIs, but whether hemorrhage plays a role in reperfusion-mediated MI expansion is not known.

METHODS

We studied cardiac troponin kinetics (cTn) of ST-segment elevation MI patients (n = 70) classified by cardiovascular magnetic resonance to be hemorrhagic (70%) or nonhemorrhagic following primary percutaneous coronary intervention. To isolate the effects of hemorrhage from ischemic burden, we performed controlled canine studies (n = 25), and serially followed both cTn and MI size with time-lapse imaging.

RESULTS

CTn was not different before reperfusion; however, an increase in cTn following primary percutaneous coronary intervention peaked earlier (12 hours vs 24 hours; P < 0.05) and was significantly higher in patients with hemorrhage (P < 0.01). In hemorrhagic animals, reperfusion led to rapid expansion of myocardial necrosis culminating in epicardial involvement, which was not present in nonhemorrhagic cases (P < 0.001). MI size and salvage were not different at 1 hour postreperfusion in animals with and without hemorrhage (P = 0.65). However, within 72 hours of reperfusion, a 4-fold greater loss in salvageable myocardium was evident in hemorrhagic MIs (P < 0.001). This paralleled observations in patients with larger MIs occurring in hemorrhagic cases (P < 0.01).

CONCLUSIONS

Myocardial hemorrhage is a determinant of MI size. It drives MI expansion after reperfusion and compromises myocardial salvage. This introduces a clinical role of hemorrhage in acute care management, risk assessment, and future therapeutics.

Coronary blood flow in heart failure: cause, consequence and bystander

Heart failure is a clinical syndrome where cardiac output is not sufficient to sustain adequate perfusion and normal bodily functions, initially during exercise and in more severe forms also at rest. The two most frequent forms are heart failure of ischemic origin and of non-ischemic origin. In heart failure of ischemic origin, reduced coronary blood flow is causal to cardiac contractile dysfunction, and this is true for stunned and hibernating myocardium, coronary microembolization, myocardial infarction and post-infarct remodeling, possibly also for the takotsubo syndrome. The most frequent form of non-ischemic heart failure is dilated cardiomyopathy, caused by genetic mutations, myocarditis, toxic agents or sustained tachyarrhythmias, where alterations in coronary blood flow result from and contribute to cardiac contractile dysfunction. Hypertrophic cardiomyopathy is caused by genetic mutations but can also result from increased pressure and volume overload (hypertension, valve disease). Heart failure with preserved ejection fraction is characterized by pronounced coronary microvascular dysfunction, the causal contribution of which is however not clear. The present review characterizes the alterations of coronary blood flow which are causes or consequences of heart failure in its different manifestations. Apart from any potentially accompanying coronary atherosclerosis, all heart failure entities share common features of impaired coronary blood flow, but to a different extent: enhanced extravascular compression, impaired nitric oxide-mediated, endothelium-dependent vasodilation and enhanced vasoconstriction to mediators of neurohumoral activation. Impaired coronary blood flow contributes to the progression of heart failure and is thus a valid target for established and novel treatment regimens.

Long non-coding RNA growth arrest specific transcript 5 acting as a sponge of MicroRNA-188-5p to regulate SMAD family member 2 expression promotes myocardial ischemia-reperfusion injury

The purpose of this work is to probe into the potential role of long non-coding RNA growth arrest specific transcript 5 (lncGAS5)/ microRNA (miR)-188-5p/SMAD2 axis in MIRI. Through ligating the left anterior descending (LAD) coronary artery, MIRI animal model and hypoxia/reoxygenation (H/R) myocardial injury model in vitro were established. Via adenovirus or plasmid transfection, lncGAS5/MiR-188-5p/SMAD2 expression was up-regulated or down-regulated in the study. RT-qPCR was applied to check LncGAS5/MiR-188-5p/SMAD2 mRNA expression, HE staining for histopathological staining, TUNEL staining and flow cytometry to examine cardiomyocyte apoptotic rate, CCK-8 to check cell viability, ELISA to detect inflammatory factor levels, Western blot to examine Bax, Bcl-2, cleaved caspase-3, NF-κB and SMAD2 expression, and dual luciferase reporter experiment to examine the targeting relationship of miR-188-5p with LncGAS5 and SMAD2. The results indicated that LncGAS5 and SMAD2 were highly expressed in MIRI and miR-188-5p was under-expressed. Silencing LncGAS5 and SMAD2 or overexpressing miR-188-5p could reduce MIRI in myocardial tissue, cardiomyocyte apoptosis, inhibit Bax, cleaved caspase-3 and NF-κB expressions and promote Bcl-2 expression, while reducing inflammatory factors TNF -α, IL-1β and IL-6 levels. Overexpressing LncGAS5 promoted MIRI. Additionally, the impact of silencing LncGAS5 on MIRI could be reversed through inhibiting miR-188-5p. LncGAS5 acted as a sponge of miR-188-5p to target SMAD2 expression. In conclusion, Silencing LncGAS5 is available to improve MIRI through regulating miR-188-5p/SMAD2 axis, and may be used as a potential target for treating MIRI in the future.

Myocardial Ischemia-Reperfusion Injury: Therapeutics from a Mitochondria-Centric Perspective

Coronary arterial disease is the most common cardiovascular disease. Myocardial ischemia-reperfusion injury caused by the initial interruption of organ blood flow and subsequent restoration of organ blood flow is an important clinical problem with various cardiac reperfusion strategies after acute myocardial infarction. Even though blood flow recovery is necessary for oxygen and nutrient supply, reperfusion causes pathological sequelae that lead to the aggravation of ischemic injury. At present, although it is known that injury will occur after reperfusion, clinical treatment always focuses on immediate recanalization. Mitochondrial fusion, fission, biogenesis, autophagy, and their intricate interaction constitute an effective mitochondrial quality control system. The mitochondrial quality control system plays an important role in maintaining cell homeostasis and cell survival. The removal of damaged, aging, and dysfunctional mitochondria is mediated by mitochondrial autophagy. With the help of appropriate changes in mitochondrial dynamics, new mitochondria are produced through mitochondrial biogenesis to meet the energy needs of cells. Mitochondrial dysfunction and the resulting oxidative stress have been associated with the pathogenesis of ischemia/reperfusion (I/R) injury, which play a crucial role in the pathophysiological process of myocardial injury. This review aimed at elucidating the mitochondrial quality control system and establishing the possibility of using mitochondria as a potential therapeutic target in the treatment of I/R injuries.

Cardiac MRI to Visualize Myocardial Damage after ST-Segment Elevation Myocardial Infarction: A Review of Its Histologic Validation

Cardiac MRI is a noninvasive diagnostic tool using nonionizing radiation that is widely used in patients with ST-segment elevation myocardial infarction (STEMI). Cardiac MRI depicts different prognosticating components of myocardial damage such as edema, intramyocardial hemorrhage (IMH), microvascular obstruction (MVO), and fibrosis. But how do cardiac MRI findings correlate to histologic findings? Shortly after STEMI, T2-weighted imaging and T2* mapping cardiac MRI depict, respectively, edema and IMH. The acute infarct size can be determined with late gadolinium enhancement (LGE) cardiac MRI. T2-weighted MRI should not be used for area-at-risk delineation because T2 values change dynamically over the first few days after STEMI and the severity of T2 abnormalities can be modulated with treatment. Furthermore, LGE cardiac MRI is the most accurate method to visualize MVO, which is characterized by hemorrhage, microvascular injury, and necrosis in histologic samples. In the chronic setting post-STEMI, LGE cardiac MRI is best used to detect replacement fibrosis (ie, final infarct size after injury healing). Finally, native T1 mapping has recently emerged as a contrast material-free method to measure infarct size that, however, remains inferior to LGE cardiac MRI. Especially LGE cardiac MRI-defined infarct size and the presence and extent of MVO may be used to monitor the effect of new therapeutic interventions in the treatment of reperfusion injury and infarct size reduction. © RSNA, 2021 Online supplemental material is available for this article.

Assessment of intramyocardial hemorrhage with dark-blood T2*-weighted cardiovascular magnetic resonance

BACKGROUND

Intramyocardial hemorrhage (IMH) within myocardial infarction (MI) is associated with major adverse cardiovascular events. Bright-blood T2*-based cardiovascular magnetic resonance (CMR) has emerged as the reference standard for non-invasive IMH detection. Despite this, the dark-blood T2*-based CMR is becoming interchangeably used with bright-blood T2*-weighted CMR in both clinical and preclinical settings for IMH detection. To date however, the relative merits of dark-blood T2*-weighted with respect to bright-blood T2*-weighted CMR for IMH characterization has not been studied. We investigated the diagnostic capacity of dark-blood T2*-weighted CMR against bright-blood T2*-weighted CMR for IMH characterization in clinical and preclinical settings.

MATERIALS AND METHODS

Hemorrhagic MI patients (n = 20) and canines (n = 11) were imaged in the acute and chronic phases at 1.5 and 3 T with dark- and bright-blood T2*-weighted CMR. Imaging characteristics (Relative signal-to-noise (SNR), Relative contrast-to-noise (CNR), IMH Extent) and diagnostic performance (sensitivity, specificity, accuracy, area-under-the-curve, and inter-observer variability) of dark-blood T2*-weighted CMR for IMH characterization were assessed relative to bright-blood T2*-weighted CMR.

RESULTS

At both clinical and preclinical settings, compared to bright-blood T2*-weighted CMR, dark-blood T2*-weighted images had significantly lower SNR, CNR and reduced IMH extent (all p < 0.05). Dark-blood T2*-weighted CMR also demonstrated weaker sensitivity, specificity, accuracy, and inter-observer variability compared to bright-blood T2*-weighted CMR (all p < 0.05). These observations were consistent across infarct age and imaging field strengths.

CONCLUSION

While IMH can be visible on dark-blood T2*-weighted CMR, the overall conspicuity of IMH is significantly reduced compared to that observed in bright-blood T2*-weighted images, across infarct age in clinical and preclinical settings at 1.5 and 3 T. Hence, bright-blood T2*-weighted CMR would be preferable for clinical use since dark-blood T2*-weighted CMR carries the potential to misclassify hemorrhagic MIs as non-hemorrhagic MIs.

Reducing Cardiac Injury during ST-Elevation Myocardial Infarction: A Reasoned Approach to a Multitarget Therapeutic Strategy

The significant reduction in ‘ischemic time’ through capillary diffusion of primary percutaneous intervention (pPCI) has rendered myocardial-ischemia reperfusion injury (MIRI) prevention a major issue in order to improve the prognosis of ST elevation myocardial infarction (STEMI) patients. In fact, while the ischemic damage increases with the severity and the duration of blood flow reduction, reperfusion injury reaches its maximum with a moderate amount of ischemic injury. MIRI leads to the development of post-STEMI left ventricular remodeling (post-STEMI LVR), thereby increasing the risk of arrhythmias and heart failure. Single pharmacological and mechanical interventions have shown some benefits, but have not satisfactorily reduced mortality. Therefore, a multitarget therapeutic strategy is needed, but no univocal indications have come from the clinical trials performed so far. On the basis of the results of the consistent clinical studies analyzed in this review, we try to design a randomized clinical trial aimed at evaluating the effects of a reasoned multitarget therapeutic strategy on the prevention of post-STEMI LVR. In fact, we believe that the correct timing of pharmacological and mechanical intervention application, according to their specific ability to interfere with survival pathways, may significantly reduce the incidence of post-STEMI LVR and thus improve patient prognosis.

[Cardiac ruptures in acute myocardial infarction]

Presented in the article are the generalized data of the Russian and foreign literature addressing the currently important problem of myocardial ruptures as one of the most dangerous complications of infarction, also analysing the results of clinical studies on interconnection of heart ruptures with systemic thrombolytic therapy and with a percutaneous coronary intervention. This is followed by describing the mechanisms that may lead to myocardial rupture during thrombolytic therapy and surgical endovascular treatment, underlying the necessity of pharmacological pre- and post-conditioning for prevention of reperfusion myocardial lesions. The article also touches upon the clinical and instrumental diagnosis of myocardial ruptures, as well as approaches to surgical treatment depending on the type of rupture and necessity of myocardial revascularization.

Impact of microvascular injury various types on function of left ventricular in patients with primary myocardial infarction with ST segment elevation

AIM

To analyze the long-term effect of microvascular injury various types on the structural and functional parameters of the left ventricle assessed by echocardiography in patients with primary ST-segment elevation myocardial infarction (STEMI).

MATERIALS AND METHODS

The study included 60 patients with primary STEMI admitted within the first 12 hours after the onset of disease who underwent stenting of the infarct-associated coronary artery. Each patient included in the study underwent CMR imaging on the second day post-STEMI. MVO and IMH were assessed using late gadolinium enhancement and T2-weighted CMR imaging. Subsequently, all patients underwent the standard echocardiographic protocol on the 7th day and 3 months after MI.

RESULTS

We divided all patients into 4 groups: the 1st group didn't have any phenomena of IMH and MVO, the 2nd group had only MVO, patients of the 3rd group had only IMH and in the 4th group there was a combination of MVO and IMH. LV ejection fraction was significantly lower in patients with combination of MVO and IMH, if compared to those without it. Correlation analysis showed a moderate inverse correlation between the MVO area and LV contractile function: the larger the area, the lower the LVEF (R=-0,60; p=0,000002).

CONCLUSIONS

The combination of IMH and MVO is a predictor of a reduction in LVEF and an increase of volumetric measurements within 3 months after MI. In comparison with patients without microvascular injury isolated MVO is associated with lower LVEF. The size of MVO is directly correlated with the LV contractile function decrease. Isolated IMH was not associated with deterioration of left ventricular function.

Screening and identification of potential protein biomarkers for the early diagnosis of acute myocardial infarction

Background

Acute myocardial infarction (AMI) is the most serious type of heart disease. Clinically, there is an urgent need to discover diagnostic biomarkers for the early diagnosis of AMI.

Methods

Serum proteomic profiles in AMI patients, healthy controls, and stable angina pectoris (SAP) patients were explored and compared by iTRAQ-2DLC-MS/MS. The clinical data of AMI patients were also analyzed. Differentially expressed proteins were validated by enzyme linked immunosorbent assay (ELISA), and diagnostic models were constructed.

Results

A total of 39 differentially expressed proteins were identified in AMI patients. The results showed that the serum levels of apolipoprotein E (APOE) in AMI patients were notably higher than those in the healthy controls (P=0.0172). The serum levels of aspartate aminotransferase (AATC) in AMI patients were markedly higher than those in the healthy controls and SAP patients (P<0.0001 and P<0.0001, respectively). The serum levels of fibronectin (FINC) in SAP patients were significantly higher than those in the healthy controls and AMI patients (P=0.0043 and P=0.0044, respectively). Clinical data analysis showed a considerable difference in blood glucose levels, troponin I (TNI), and creatine kinase (CK) in AMI patients compared with SAP patients and healthy controls. A diagnostic model consisting of AATC and clinical indicators [lactate dehydrogenase (LDH) and CK] was established to distinguish between AMI patients and healthy controls, with an area under the curve (AUC) value of 0.993 sensitivity and specificity of 96.2% and 96.3%, respectively. A diagnostic model consisting of AATC and CK was established to distinguish between AMI patients and SAP patients, with an AUC value of 0.975 and a sensitivity and specificity of 85.2% and 79.30%, respectively.

Conclusions

In this study, differentially expressed proteins in AMI patients were combined with clinical indexes, LDH and CK, and two diagnostic models were constructed. This study may provide meaningful data for the early diagnosis of AMI.

Adjunctive Intracoronary Fibrinolytic Therapy During Primary Percutaneous Coronary Intervention

Despite routinely restoring epicardial coronary patency, with primary percutaneous coronary intervention (PCI), microvascular obstruction affects approximately half of patients and confers an adverse prognosis. There are no evidence-based treatments for microvascular obstruction. A key contributor to microvascular obstruction is distal embolisation and microvascular thrombi. Adjunctive intracoronary fibrinolytic therapy may reduce thrombotic burden, potentially reducing distal embolisation of atherothrombotic debris to the microcirculation. In this review, the evidence from published randomised trials on the effects of adjunctive intracoronary fibrinolytic therapy during primary PCI is critically appraised, the ongoing randomised trials are described, and conclusions are made from the available evidence. Clinical uncertainties, to be addressed by future research, are highlighted.

Prognostic value and clinical predictors of intramyocardial hemorrhage measured by CMR T2* sequences in STEMI

Recent studies show that microvascular injury consists of microvascular obstruction (MVO) and intramyocardial hemorrhage (IMH). In patients with reperfused ST-segment elevation myocardial infarction (STEMI) quantitative assessment of IMH with T2* cardiovascular magnetic resonance imaging (CMR) appears to be useful in evaluation of microvascular damage. The current study aimed to investigate feasibility of this approach and to correlate IMH with clinical and CMR parameters. A single center observational cohort study was performed in reperfused STEMI patients with CMR examination 7 days (IQR: 5 to 8 days) after percutaneous coronary intervention. Infarct size (IS) and MVO were evaluated in short-axis late gadolinium enhancement sequences and IMH with whole LV volume T2* mapping sequences. Of the 94 patients, MVO was identified in 52% of patients and the median size of MVO was 3% of LV mass (IQR: 1.5 to 5.4%). IMH was present in 28% of patients and the median size of IMH was 1.1% of LV mass (IQR: 0.5 to 2.9%). IMH extent was independently associated with anterior myocardial infarction (p = 0.022) and thrombectomy (p = 0.049). IMH was correlated with MVO (R = 0.62, p < 0.001), necrosis (R = 0.58, p < 0.001) and LVEF (R = -0.21, p = 0.04). Patients with IMH presented higher incidence of MACE events, independently of LVEF (p = 0.022). T2* mapping is a novel imaging approach that proves useful to asses IMH in the setting of reperfused STEMI. T2* IMH extent was associated with anterior infarction and thrombectomy. T2* IMH was associated with higher incidence of MACE events regardless preserved or reduced LVEF.

Angiogenesis after acute myocardial infarction

Acute myocardial infarction (MI) inflicts massive injury to the coronary microcirculation leading to vascular disintegration and capillary rarefication in the infarct region. Tissue repair after MI involves a robust angiogenic response that commences in the infarct border zone and extends into the necrotic infarct core. Technological advances in several areas have provided novel mechanistic understanding of postinfarction angiogenesis and how it may be targeted to improve heart function after MI. Cell lineage tracing studies indicate that new capillary structures arise by sprouting angiogenesis from pre-existing endothelial cells (ECs) in the infarct border zone with no meaningful contribution from non-EC sources. Single-cell RNA sequencing shows that ECs in infarcted hearts may be grouped into clusters with distinct gene expression signatures, likely reflecting functionally distinct cell populations. EC-specific multicolour lineage tracing reveals that EC subsets clonally expand after MI. Expanding EC clones may arise from tissue-resident ECs with stem cell characteristics that have been identified in multiple organs including the heart. Tissue repair after MI involves interactions among multiple cell types which occur, to a large extent, through secreted proteins and their cognate receptors. While we are only beginning to understand the full complexity of this intercellular communication, macrophage and fibroblast populations have emerged as major drivers of the angiogenic response after MI. Animal data support the view that the endogenous angiogenic response after MI can be boosted to reduce scarring and adverse left ventricular remodelling. The improved mechanistic understanding of infarct angiogenesis therefore creates multiple therapeutic opportunities. During preclinical development, all proangiogenic strategies should be tested in animal models that replicate both cardiovascular risk factor(s) and the pharmacotherapy typically prescribed to patients with acute MI. Considering that the majority of patients nowadays do well after MI, clinical translation will require careful selection of patients in need of proangiogenic therapies.