Reperfusion In Myocardial Infarction Research Articles

Illusion of revascularization: does anyone achieve optimal revascularization during percutaneous coronary intervention?

This Perspective article is a form of 'pastiche', inspired by the 1993 review by Lincoff and Topol entitled 'Illusion of reperfusion', and explores how their concept continues to apply to percutaneous revascularization in patients with coronary artery disease and ischaemia. Just as Lincoff and Topol argued that reperfusion of acute myocardial infarction was facing unresolved obstacles that hampered clinical success in 1993, we propose that challenging issues are similarly jeopardizing the potential benefits of stent-based angioplasty today. By analysing the appropriateness and efficacy of percutaneous coronary intervention (PCI), we emphasize the limitations of relying solely on visual angiographic guidance, which frequently leads to inappropriate stenting and overtreatment in up to one-third of patients and the associated increased risk of periprocedural myocardial infarction. The lack of optimal revascularization observed in half of patients undergoing PCI confers risks such as suboptimal physiology after PCI, residual angina and long-term stent-related events, leaving an estimated 76% of patients with an 'illusion of revascularization'. These outcomes highlight the need to refine our diagnostic tools by integrating physiological assessments with targeted intracoronary imaging and emerging strategies, such as co-registration systems and angiography-based computational methods enhanced by artificial intelligence, to achieve optimal revascularization outcomes.

Intracoronary microcatheter indwelling for continuous pumping of low-dose thrombolytic drugs: A new approach to reperfusion in acute myocardial infarction.

Reperfusion therapy of acute myocardial infarction (AMI) refers to physical or chemical recanalization and restoration of blood flow to an occluded coronary artery, and current techniques for reperfusion therapy include intravenous thrombolysis, percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG). The number of patients receiving emergency CABG in the real world is decreasing due to the disadvantages of CABG and the improvement in PCI procedures. Thrombolytic therapy has some disadvantages such as low recanalization rate, high risk of reocclusion and bleeding, and short time window. On the other hand, intracoronary interventional therapy may meet the requirements of "early, complete and persistent" patency of coronary arteries at different time points. However, in the emergency PCI, although thrombus aspiration via a catheter or balloon dilation is performed, residual thrombus with heavy or low TIMI (thrombolysis in myocardial infarction) myocardial perfusion grading is still observed in some patients, suggesting disordered microcirculation. Currently, the treatment of microcirculatory disturbance in emergency PCI mainly employed injection of tirofiban, adenosine, thrombolytic agent or other drugs into the local area via a microcatheter in a short time, all of which can significantly reduce the thrombus load and improve TIMI perfusion. Herein, we report that a microcatheter was indwelled in the coronary artery for continuous pumping of low-dose thrombolytic drugs as reperfusion therapy in 12 patients with acute and subacute MI.

Determinants and Prognoses of Visual-Functional Mismatches After Mechanical Reperfusion in ST-Elevation Myocardial Infarction.

Discordance between the anatomy and physiology of the coronary has important implications for managing patients with stable coronary disease, but its significance in ST-elevation myocardial infarction has not been fully elucidated. The retrospective study involved patients diagnosed with ST-elevation myocardial infarction (STEMI) who underwent percutaneous coronary intervention (PCI), along with quantitative coronary angiography (QCA) and quantitative flow ratio (QFR) assessments. Patients were stratified into four groups regarding the severity of the culprit vessel, both visually and functionally: concordantly negative (QCA-diameter stenosis [DS] ≤ 50% and QFR > 0.80), mismatch (QCA-DS > 50% and QFR > 0.80), reverse mismatch (QCA-DS ≤ 50% and QFR ≤ 0.80), and concordantly positive (QCA-DS > 50% and QFR ≤ 0.80). Multivariable logistic regression analyses were conducted to identify the clinical factors linked to visual-functional mismatches. Kaplan‒Meier analysis was conducted to estimate the 18-month adverse cardiovascular events (MACE)-free survival between the four groups. The study involved 310 patients, with 68 presenting visual-functional mismatch, and 51 exhibiting reverse mismatch. The mismatch was associated with higher angiography-derived microcirculatory resistance (AMR) (adjusted odds ratio [aOR]=1.016, 95% CI: 1.010-1.022, P<0.001). Reverse mismatch was associated with larger area stenosis (aOR=1.044, 95% CI: 1.004-1.086, P=0.032), lower coronary flow velocity (aOR=0.690, 95% CI: 0.567-0.970, P<0.001) and lower AMR (aOR=0.947, 95% CI: 0.924-0.970, P<0.001). Additionally, the mismatch group showed the worst 18-month MACE-free survival among the four groups (Log rank test p = 0.013). AMR plays a significant role in the occurrence of visual-functional mismatches between QCA-DS and QFR, and the mismatch group showed the worst prognosis.

[Position statement for improvement in reperfusion of ST-elevation myocardial infarction in Latin America].

The treatment of ST-segment elevation myocardial infarction has barriers depending on the geographic region. Primary coronary angioplasty is the treatment of choice, if it is performed on time and by experienced operators. However, when it is not available, the administration of fibrinolysis and referral for rescue angioplasty, in case of negative reperfusion, is the best strategy. In the same way, coronary angioplasty, as part of a pharmacoinvasive strategy, is the best alternative when there is positive reperfusion. The development of infarct treatment networks increases the number of patients reperfused within the recommended times and improves outcomes. In Latin America, national myocardial infarction treatment programs should focus on improving outcomes, and long-term success depends on working toward defined goals and enhancing functionality, therefore programs should develop capacity to measure their performance. The following document discusses all of these alternatives and suggests opportunities for improvement.

Principle and design of clinical efficacy observation of extracorporeal cardiac shock wave therapy for patients with myocardial ischemia-reperfusion injury: A prospective randomized controlled trial protocol

Background Acute ST-segment elevation myocardial infarction (STEMI) remains a serious life threatening event with a poor prognosis due to myocardial ischemia/reperfusion injury despite coronary revascularization. Extracorporeal cardiac shock wave (ECSW) is a safe, effective and non-invasive new method for the treatment of cardiovascular diseases. The current results show that extracorporeal cardiac shock wave provides a new treatment option for patients with severe and advanced coronary heart disease. However, there are relatively few clinical studies on the application of in vitro cardiac shock waves in patients with myocardial ischemia-reperfusion injury. We hypothesized that extracorporeal cardiac shock therapy would also be effective in reducing clinical endpoints in patients with STEMI reperfusion. Objective This study is order to provide a new therapeutic method for patients with myocardial ischemia-reperfusion injury and reveal the possible mechanism of ECSW for ischemia-reperfusion injury. Methods and materials CEECSWIIRI is a single-center, prospective randomized controlled trial that plans to enroll 102 eligible patients with acute ST-segment elevation myocardial infarction reperfusion. Eligible patients with STEMI reperfusion will be randomly divided into external cardiac shock therapy (ECSW) trial group and blank control group. The blank control group will receive optimal drug therapy, and the experimental group will receive optimal drug therapy combined with ECSW. The shock wave treatment plan will be 3-month therapy, specifically 1 week of treatment per month, 3 weeks of rest, 3 times of ECSW in each treatment week, respectively on the first day, the third day and the fifth day of the treatment week, lasting for 3 months and follow-up for 2 years. The primary endpoint will be to assess the 2-year improvement in all-cause death, re-hospitalization due to cardiovascular disease, major unintentional cerebrovascular events, including cardiogenic death, myocardial infarction, heart failure, arrhythmia, emergency coronary revascularization, and stroke in patients with STEMI reperfusion. Secondary endpoints will include improvements in angina pectoris, quality of life, cardiac structure and function, coronary microcirculation, and endothelial progenitor cell-derived miR-140-3p in relation to survival outcomes. Trial registration number ClinicalTrial.gov.org PRS:NCT05624203; Date of registration: November 12, 2022.

Reperfusion Arrhythmia in Acute Myocardial Infarction

Management of reperfusion in acute myocardial infarction is an important component of myocardial cell survival to minimize the area experiencing infarction and improve patient clinical outcomes. However, this reperfusion also contributes to myocardial injury which is preceded by the ischemic process. One of the injuries related to the ischemia-reperfusion process in the myocardium is reperfusion arrhythmia. Reperfusion arrhythmias from several studies can begin to occur in the first minutes after restoration of obstructed coronary flow. The features of reperfusion arrhythmia can include accelerated idioventricular rhythm, ventricular tachycardia, ventricular fibrillation, and other arrhythmias. The mechanism of reperfusion arrhythmia can be excess calcium in the cells, oxidative stress due to an increase reactive oxygen species, energy metabolism disorders, and neutrophil accumulation. Excessive intracellular calcium and other mechanisms cause a delay in the depolarization of previously ischemic cells. This reperfusion arrhythmia requires special attention because it can disrupt hemodynamics and patient outcomes after reperfusion procedures. Knowledge of the mechanisms of reperfusion arrhythmias will guide clinicians to provide better management during and after reperfusion procedures.

Non-contrast cine cardiovascular magnetic resonance-based radiomics nomogram for predicting microvascular obstruction after reperfusion in ST-segment elevation myocardial infarction.

This study aimed to develop and validate a cine cardiovascular magnetic resonance (CMR)-based radiomics nomogram model for predicting microvascular obstruction (MVO) following reperfusion in patients with ST-segment elevation myocardial infarction (STEMI). In total, 167 consecutive STEMI patients were retrospectively enrolled. The patients were randomly divided into training and validation cohorts with a ratio of 7:3. All patients were diagnosed with myocardial infarction with or without MVO based on late gadolinium enhancement imaging. Radiomics features were extracted from the cine CMR end-diastolic volume phase of the entire left ventricular myocardium (3D volume). The least absolute shrinkage and selection operator (LASSO) regression was employed to select the features that were most relevant to the MVO; these features were then used to calculate the radiomics score (Rad-score). A combined model was developed based on independent risk factors screened using multivariate regression analysis and visualized using a nomogram. Performance was assessed using receiver operating characteristic curve, calibration curve, and decision curve analysis (DCA). The univariate analysis of clinical features demonstrated that only cardiac troponin I (cTNI) was significantly associated with MVO. LASSO regression revealed that 12 radiomics features were strongly associated with MVO. Multivariate regression analysis indicated that cTNI and Rad-score were independent risk factors for MVO. The nomogram based on these two features achieved an area under the curve of 0.86 and 0.78 in the training and validation cohorts, respectively. Calibration curves and DCA indicated the clinical feasibility and utility of the nomogram. A CMR-based radiomics nomogram offers an effective means of predicting MVO without contrast agents and radiation, which could facilitate risk stratification of patients with STEMI after PCI for reperfusion.

Prognostic role of left atrial morpho-functional parameters in left ventricular remodeling following acute st-elevation myocardial infarction

Abstract Funding Acknowledgements Type of funding sources: None. Background Despite prompt reperfusion and optimal medical therapy of acute ST-elevation myocardial infarction (STEMI), patients may undergo left ventricular (LV) remodeling (REM), which may lead to systolic and/or diastolic heart failure. Little is known regarding factors and mechanisms leading to LV REM, and this knowledge gap hinders potential strategies to prevent this complication. Left atrium (LA) functional and dimensional parameters are emerging as independent prognostic markers in ischemic heart disease. Purpose The present study aims at exploring the potential role of LA morpho-functional parameters by CMR-FT in predicting LV REM following STEMI. Methods This study derives from a sub-analysis of the prospective and multicenter "VavirimS" trial. All patients were assessed through 2 consecutive CMR scans, at 1 and 6 months after STEMI. CMR-FT was applied to both LA and LV. The endpoint was to evaluate the association between LA volumes and phasic functions with LV REM at 6-month follow up, defined as: i) LV REMEDV: ≥10% increase in LV end diastolic volume (EDV); ii) LV REMEDV-ESV: ≥12% increase in LV EDV and ≥6% LV end systolic volume (ESV). Results Out of 193 patients included in the VavirimS trial, 149 were enrolled and 44 have been excluded either for inadequate image quality for CMR-FT analysis or for the presence of factors impacting on LA morphology and function (i.e. mitral regurgitation and atrial fibrillation). LV REMEDV occurred in 34 patients (23%), who showed worse LA strain parameters (reservoir, conduit and booster function), LV global radial strain (GRS) and LV global circumferential epicardial strain [Fig. 1]. At multivariate analysis, LA reservoir and LV global radial strain (GRS) were confirmed as independent predictors of LV-REMEDV [Fig. 1]. The best cut-off for LA reservoir and LV GRS were 20% (sensitivity 97%; specificity 45%) and 56% (sensitivity 67%; specificity 69%), respectively. LV REMEDV-ESV occurred in 17 patients (11%), who showed reduced LA strain and LV GRS [Fig. 1]. The only independent predictor of LV remodeling in this group was LA reservoir [Fig. 1]. A subgroup analysis has been performed on two groups, according to EF: i) p-EF: preserved ejection fraction, ii) r-EF: reduced ejection fraction. In the p-EF group both LA reservoir and LV GRS were confirmed to be associated with LV REM [Fig. 1], while in the r-EF group the only independent predictor of LV REM was LV GRS [Fig. 1]. Conclusions CMR-derived LA reservoir and LV GRS are independent predictors of LV remodeling following STEMI. In patients with preserved EF LA reservoir is confirmed as independent predictor of LV remodeling, hinting at early and subclinical impairment of left chambers compliance. LA functional parameters following STEMI may help physicians in identifying patients at higher risk of LV remodeling.

Upregulation of P2Y14 receptor in neutrophils promotes inflammation after myocardial ischemia/reperfusion injury

BackgroundP2Y14 receptor is expressed in neutrophils and is involved in activation of inflammatory signaling. However, the expression and function of P2Y14 receptor in neutrophils after myocardial infarction/reperfusion (MIR) injury remain to be elucidated. MethodsIn this research, rodent and cellular models of MIR were used to detect the involvement and function of P2Y14 receptor, as well as the regulation of inflammatory signaling via P2Y14 receptor in neutrophils post-MIR. ResultsIn the early stage post MIR, the expression of P2Y14 receptor was upregulated in CD4+Ly-6G+ neutrophils. Additionally, the expression of P2Y14 receptor was highly induced in neutrophils subjected to uridine 5′-diphosphoglucose (UDP-Glu), which is proven to be secreted by cardiomyocytes during ischemia and reperfusion. Our results also showed the beneficial role of P2Y14 receptor antagonist PPTN in counteracting inflammation via promoting polarization of neutrophils to N2 phenotype in the infarct area of the heart tissue after MIR. ConclusionThese findings prove that the P2Y14 receptor is involved in the regulation of inflammation in the infarct area after MIR, and establish a novel signaling pathway concerning the interplay between cardiomyocytes and neutrophils in the heart tissue.

Elevated LDL Cholesterol Increases Microvascular Endothelial VWF and Thromboinflammation After Myocardial Infarction.

In reperfused myocardial infarction, VWF (von Willebrand factor)-mediated platelet adhesion contributes to impaired microvascular reflow and possibly also to postmyocardial infarction inflammation. We hypothesized that postischemic thromboinflammatory processes are worsened by elevated LDL (low-density lipoprotein) cholesterol. Myocardial ischemia-reperfusion or sham procedure was performed in wild-type mice and hyperlipidemic mice deficient for the LDL receptor and Apobec-1 (apolipoprotein-B mRNA editing enzyme catalytic polypeptide-1; DKO [double knockout]). DKO subgroups were treated with N-acetylcysteine, which inhibits pro-adhesive VWF multimers or with recombinant ADAMTS13 (a disintegrin and metalloproteinase with thrombospondin motifs-13), which enzymatically cleaves endothelial surface-associated VWF. Myocardial contrast echocardiography perfusion imaging and molecular imaging for VWF, platelet glycoprotein Ibα, and leukocyte CD18 (cluster of differentiation) were performed 30 minutes post-reperfusion. Histology, infarct sizing, and echocardiography were performed at 1.5 or 72 hours; late echocardiography was performed at day 21. After ischemia-reperfusion, DKO compared with wild-type mice had ≈2-fold higher (P<0.05) risk area signal for microvascular platelet adhesion, VWF, and CD18; greater impairment in microvascular reflow, and 2-fold larger infarct size. Treatment of DKO mice with N-acetylcysteine and ADAMTS13 reduced molecular imaging signal for microvascular platelet adhesion, VWF, and CD18; improved early microvascular reflow; and reduced eventual infarct size. ADAMTS13 suppressed the postmyocardial infarction neutrophil and monocyte infiltration, enhanced the time-dependent recovery of left ventricular systolic function, and prevented late left ventricular remodeling. In reperfused myocardial infarction, elevated LDL cholesterol promotes thromboinflammation through excess microvascular endothelial VWF and platelet adhesion, resulting in less microvascular reflow and larger infarct size. In the presence of elevated LDL cholesterol, therapies that suppress endothelial-associated VWF can promote recovery of left ventricular function and protect against remodeling.

Research progress on the effects of novel hypoglycemic drugs in diabetes combined with myocardial ischemia/reperfusion injury.

Acute myocardial infarction (AMI) reperfusion is associated with ischemia/reperfusion (I/R) injury, which leads to enlarged myocardial infarction size, poor healing of the infarcted myocardium, and poor left ventricular remodeling, thus increasing the risk of major adverse cardiovascular events (MACEs). Diabetes increases myocardial susceptibility to I/R injury, decreases myocardial responsiveness to cardioprotective strategies, exacerbates myocardial I/R injury, and expands the infarct size of AMI, thereby increasing the incidence of malignant arrhythmias and heart failure. Currently, evidence regarding pharmacological interventions for diabetes combined with AMI and I/R injury is lacking. Traditional hypoglycemic drugs have a limited role in the prevention and treatment of diabetes combined with I/R injury. Current evidence suggests that novel hypoglycemic drugs may exert a preventive effect on diabetes combined with myocardial I/R injury, especially glucagon-like peptide-1 receptor agonists (GLP-1 RA) and sodium-dependent glucose transporter protein 2 inhibitors (SGLT2i), which may increase coronary blood flow, reduce acute thrombosis, attenuate I/R injury, decrease myocardial infarction size, inhibit structural and functional remodeling of the ischemic heart, improve cardiac function, and reduce the occurrence of MACEs of diabetes patients combined with AMI via mechanisms such as reduction of inflammatory response, inhibition of oxidative stress, and improvement of vascular endothelial function. This paper will systematically elaborate the protective role and molecular mechanisms of GLP-1 RA and SGLT2i in diabetes combined with myocardial I/R injury, aiming to provide clinical assistance.

Benign Late T Wave Inversion Post Coronary Artery Bypass Grafting: Case Report of Myocardial Reperfusion Sign Appearing Late on ECG

The onset of new T wave inversion (TWI) on an electrocardiogram (ECG) has always been considered an alarming sign of myocardial ischemia. Successful myocardial infarction reperfusion is indicated by the presence of early TWI after revascularization. We report a case of benign late precordial TWI post-coronary artery bypass grafting (CABG) with no evidence of myocardial ischemia.

MicroRNA-155-5p in serum derived-exosomes promotes ischaemia-reperfusion injury by reducing CypD ubiquitination by NEDD4.

Recovery of blood flow is a therapeutic approach for myocardial infarction but paradoxically induces injury to the myocardium. Exosomes (exos) are pivotal mediators for intercellular communication that can be released by different cells and are involved in cardiovascular diseases. This study aimed to explore the possible effects and mechanisms of miR-155-5p loaded by serum-derived exos in myocardial infarction reperfusion injury (MIRI). Exos were isolated from mouse serum after induction of ischaemia reperfusion (I/R) and injected into I/R-treated mice to assess cardiac function, infarction size, and cardiomyocyte apoptosis. Primary cardiomyocytes were transfected with miR-155-5p inhibitor before treatment with oxygen-glucose deprivation and re-oxygenation (OGD/R) and exos derived from the serum of I/R-treated mice (I/R-Exos), in which Bcl-2, Bax, and cleaved-caspase-3 levels were detected. The interactions among miR-155-5p, NEDD4, and CypD were evaluated. miR-155-5p level was evidently increased in I/R-Exos than in exos from the serum of sham-operated mice (P<0.05). In comparison with the I/R group, the I/R-Exos+I/R group had increased infarct size, elevated miR-155-5p expression, and boosted apoptotic rate in mouse myocardium (P<0.05). In mice treated with I/R-Exos and I/R, miR-155-5p inhibition reduced cardiac infarct size and apoptosis (P<0.05). NEDD4 was a target gene of miR-155-5p and promoted CypD ubiquitination. Cardiomyocyte apoptosis was markedly increased in the miR-155-5p inhibitor+shNEDD4+OGD/R group versus the miR-155-5p inhibitor+OGD/R group (P<0.05), but decreased in the miR-155-5p inhibitor+shNEDD4+shCypD+OGD/R group than in the miR-155-5p inhibitor+shNEDD4+OGD/R group (P<0.05). miR-155-5p in I/R-Exos may facilitate MIRI by inhibiting CypD ubiquitination via targeting NEDD4.

Correlation of Electrocardiogram Changes with Epicardial and Myocardial Perfusion in ST-Elevation Myocardial Infarction

Background: The present study was aimed to find the correlation of electrocardiographic changes with epicardial thrombolysis in myocardial infarction (TIMI) flow grade and TIMI myocardial perfusion grade (TMPG) after reperfusion in ST-elevation myocardial infarction (STEMI). Methods: One hundred and fifty patients with STEMI were included. Reperfusion was done either by thrombolysis or primary percutaneous coronary intervention. The summed absolute ST-segment deviation and summed relative ST-segment deviation were calculated. TIMI and TMPG were assessed. The primary outcome measures were to study the correlation of summed absolute ST deviation and summed relative ST deviation with TIMI flow grade and TMPG after reperfusion. The secondary outcome measures were to compare TIMI flow grade and TMPG with respect to time since symptom onset to treatment and T-wave inversion after reperfusion. Results: There was a significant positive correlation between relative ST-segment deviation that occurred after reperfusion with TIMI flow grade (r = 0.475) and TMPG (r = 0.376). There was a significant negative correlation between absolute ST-segment deviation that occurred after reperfusion with TIMI flow grade (r = −0.194) and TMPG (r = −0.288). A significantly higher percentage (87.4%) of patients who got treatment within 1 h showed TMPG 2 and 3. A significantly higher percentage of patients who had T-wave inversion after reperfusion had TIMI flow Grade 3 and TMPG 2 and 3. Conclusions: There was a significant positive correlation between relative ST-segment deviation and significant negative correlation between absolute ST-segment deviation after reperfusion with TIMI flow grade and TMPG.

The Peripandemic Impact of the First Wave of the COVID-19 Pandemic on Management and Prognosis of ST-Segment Elevation Myocardial Infarction in China.

Rapid reperfusion of ST-segment elevation myocardial infarction (STEMI) has been challenging during the coronavirus disease 2019 (COVID-19) outbreak. Whether and to what degree there will be a residual impact when the COVID-19 pandemic has passed is unclear. This nationwide retrospective study was based on electronic records of STEMI patients registered in the Chinese Cardiovascular Association Database. We analyzed 141,375 STEMI patients (including 4871 patients in Hubei province, where 80% of COVID-19 cases in China occurred in 2019-2020) during the pre-outbreak (23 October 2019-22 January 2020), outbreak (23 January 2020-22 April 2020), and post-outbreak (23 April 2020-22 July 2020) periods. In the post-outbreak period in Hubei province, the increased in-hospital mortality dropped to become insignificant (adjusted odds ratio compared to the pre-outbreak level (aOR) 1.40, [95% confidential interval (CI): 0.97-2.03]) and was lower than that in the outbreak period (1.62 [1.09-2.41]). The decreased odds of primary percutaneous coronary intervention (PCI) (0.73 [0.55-0.96]) and timely reperfusion (0.74 [0.62-0.88]) persisted, although they were substantially improved compared to the outbreak period (aOR of primary PCI: 0.23 [0.18-0.30] and timely reperfusion: 0.43 [0.35-0.53]). The residual impact of COVID-19 on STEMI in the post-outbreak period in non-Hubei provinces was insignificant. Residual pandemic impacts on STEMI management persisted after the first wave of the COVID-19 outbreak in Hubei province, the earliest and hardest hit area in China.

Usefulness of a Perfusion Balloon for Intraprocedural Stent Thrombosis in a Patient With ST-Segment Elevated Myocardial Infarction Complicated With Cardiogenic Shock

Intraprocedural stent thrombosis is a rare but serious complication of reperfusion therapy for acute coronary syndrome. There is currently no consensus on the intraprocedural management of intraprocedural stent thrombosis. It is difficult to attain thrombolysis in myocardial infarction flow grade 3, particularly in cases of cardiogenic shock. A 49-year-old man who presented with anterior ST-segment elevated acute myocardial infarction with cardiogenic shock underwent emergency percutaneous coronary intervention to diffuse proximal lesions in the left anterior descending artery under the support of intra-aortic balloon pumping. Intraprocedural stent thrombosis occurred following the postdilations with a 3.5- × 38-mm everolimus-eluting stent. Despite administration of argatroban and nitroprusside, and after frequent balloon inflations using 3.5-mm noncompliant balloons and thrombectomy, the no-reflow phenomenon was repetitively established. However, after brief and prolonged balloon inflations using 3.5- and 3-mm Ryusei perfusion balloon catheters (Kaneka Medix), the diffusely protruded thrombus inside the stent regressed, and thrombolysis in myocardial infarction flow grade 3 was obtained. The final intravascular ultrasound image showed a well-suppressed, in-stent thrombus and 24% gain of stent area (from 7.5 to 9.3 mm2). A Ryusei perfusion balloon enabled frequent, long inflation times without deteriorating hemodynamics during reperfusion in ST-segment elevated acute myocardial infarction complicated with cardiogenic shock. Thus, extended balloon inflation using a perfusion balloon is deemed a viable option not only for intraprocedural stent thrombosis but also for cases with a high burden of thrombi during the primary stenting procedure for patients with acute coronary syndrome.

The Barriers to Rapid Reperfusion in Acute ST-Elevation Myocardial Infarction.

This study aimed to quantify the contribution of various obstacles to timely reperfusion therapy in acute ST-elevation myocardial infarction (STEMI) and to improve performance in a mixed remote rural/urban region. From November1, 2020 to April23, 2021, patients with acute STEMI were prospectively monitored with the critical time intervals, treatment modalities, and outcomes registered. Selected clinical decision-makers in 11 hospitals were appointed as improvement agents and systematically provided with weekly updated information about absolute and relative performance. Suggestions for improvements were invited and shared. Only 29% of the 146 patients received reperfusion therapy within recommended time limits [prehospital thrombolysis, 2/48; in-hospital thrombolysis, 0/20; primary percutaneous coronary intervention (pPCI), 37/68, with median intervals from the first medical contact of 44, 49, and 133min, respectively]. Efficiency varied considerably between health trusts: median time from the first medical contact to prehospital thrombolysis ranged from 29 to 54min (hazard ratio 4.89). The predominant, remediable causes for delays were erroneous tactical choices and protracted electrocardiographic diagnostication, decision-making, and administration of fibrinolytic medication. During the trial, the time to pPCI was non-significantly reduced. We found several targets for system improvements in order to mitigate reperfusion delays along the entire chain of care, regardless of reperfusion modality chosen. More patients should receive prehospital thrombolysis. The most important measures will be training to ensure a more efficient on-site workflow, improved protocols and infrastructure facilitating the communication between first responders and in-hospital clinicians, and education emphasizing prehospital transport times. NCT04614805.

Serial block face scanning electron microscopy reveals region-dependent remodelling of transverse tubules post-myocardial infarction.

The highly organized transverse tubule (t-tubule) network facilitates cardiac excitation–contraction coupling and synchronous cardiac myocyte contraction. In cardiac failure secondary to myocardial infarction (MI), changes in the structure and organization of t-tubules result in impaired cardiac contractility. However, there is still little knowledge on the regional variation of t-tubule remodelling in cardiac failure post-MI. Here, we investigate post-MI t-tubule remodelling in infarct border and remote regions, using serial block face scanning electron microscopy (SBF-SEM) applied to a translationally relevant sheep ischaemia reperfusion MI model and matched controls. We performed minimally invasive coronary angioplasty of the left anterior descending artery, followed by reperfusion after 90 min to establish the MI model. Left ventricular tissues obtained from control and MI hearts eight weeks post-MI were imaged using SBF-SEM. Image analysis generated three-dimensional reconstructions of the t-tubular network in control, MI border and remote regions. Quantitative analysis revealed that the MI border region was characterized by t-tubule depletion and fragmentation, dilation of surviving t-tubules and t-tubule elongation. This study highlights region-dependent remodelling of the tubular network post-MI and may provide novel localized therapeutic targets aimed at preservation or restoration of the t-tubules to manage cardiac contractility post-MI.This article is part of the theme issue ‘The cardiomyocyte: new revelations on the interplay between architecture and function in growth, health, and disease’.

Late myocardial reperfusion in ST-elevation myocardial infarction: protocol for a systematic review and meta-analysis

IntroductionST-segment elevation myocardial infarction (STEMI) is the most severe clinical form of acute myocardial infarction, for which the current treatment consists of effective and timely myocardial reperfusion (within 12 hours...

Early donepezil monotherapy or combination with metoprolol significantly prevents subsequent chronic heart failure in rats with reperfused myocardial infarction

Despite the presence of clinical guidelines recommending that β-blocker treatment be initiated early after reperfused myocardial infarction (RMI), acute myocardial infarction remains a leading cause of chronic heart failure (CHF). In this study, we compared the effects of donepezil, metoprolol, and their combination on the progression of cardiac remodeling in rats with RMI. The animals were randomly assigned to untreated (UT), donepezil-treated (DT), metoprolol-treated (MT), and a combination of donepezil and metoprolol (DMT) groups. On day 8 after surgery, compared to the UT, the DT and DMT significantly improved myocardial salvage, owing to the suppression of macrophage infiltration and apoptosis. After the 10-week treatment, the DT and DMT exhibited decreased heart rate, reduced myocardial infarct size, attenuated cardiac dysfunction, and decreased plasma levels of brain natriuretic peptide and catecholamine, thereby preventing subsequent CHF. These results suggest that donepezil monotherapy or combined therapy with β-blocker may be an alternative pharmacotherapy post-RMI.