Left Ventricular Unloading Before Reperfusion Promotes Functional Recovery After Acute Myocardial Infarction

Automated control of Impella maintains optimal left ventricular unloading during periods of unstable hemodynamics and prevents myocardial damage in acute myocardial infarction

BACKGROUND

Left ventricular (LV) unloading by Impella, an intravascular microaxial pump, has been shown to exert dramatic cardioprotective effects in acute clinical settings of cardiovascular diseases. Total Impella support (no native LV ejection) is far more efficient in reducing LV energetic demand than partial Impella support, but the manual control of pump speed to maintain stable LV unloading is difficult and impractical. We aimed to develop an Automatic IMpella Optimal Unloading System (AIMOUS), which controls Impella pump speed to maintain LV unloading degree using closed-feedback control. We validated the AIMOUS performance in an animal model.

METHODS

In dogs, we identified the transfer function from pump speed to LV systolic pressure (LVSP) under total support conditions (n = 5). Using the transfer function, we designed the feedback controller of AIMOUS to keep LVSP at 40 mmHg and examined its performance by volume perturbations (n = 9). Lastly, AIMOUS was applied in the acute phase of ischemia-reperfusion in dogs. Four weeks after ischemia-reperfusion, we assessed LV function and infarct size (n = 10).

RESULTS

AIMOUS maintained constant LVSP, thereby ensuring a stable LV unloading condition regardless of volume withdrawal or infusion (±8 ml/kg from baseline). AIMOUS in the acute phase of ischemia-reperfusion markedly improved LV function and reduced infarct size (No Impella support: 13.9 ± 1.3 vs. AIMOUS: 5.7 ± 1.9%, P < 0.05).

CONCLUSIONS

AIMOUS is capable of maintaining optimal LV unloading during periods of unstable hemodynamics. Automated control of Impella pump speed in the acute phase of ischemia-reperfusion significantly reduced infarct size and prevented subsequent worsening of LV function.

How preclinical models help to improve outcome in cardiogenic shock

PURPOSE OF REVIEW

Preclinical experimentation of cardiogenic shock resuscitation on large animal models represents a powerful tool to decipher its complexity and improve its poor outcome, when small animal models are lacking external validation, and clinical investigation are limited due to technical and ethical constraints. This review illustrates the currently available preclinical models addressing reliably the physiopathology and hemodynamic phenotype of cardiogenic shock, highlighting on the opposite questionable translation based on low severity acute myocardial infarction (AMI) models.

RECENT FINDINGS

Three types of preclinical models replicate reliably AMI-related cardiogenic shock, either with coronary microembolization, coronary deoxygenated blood perfusion or double critical coronary sub-occlusion. These models overcame the pitfall of frequent periprocedural cardiac arrest and offer, to different extents, robust opportunities to investigate pharmacological and/or mechanical circulatory support therapeutic strategies, cardioprotective approaches improving heart recovery and mitigation of the systemic inflammatory reaction. They all came with their respective strengths and weaknesses, allowing the researcher to select the right preclinical model for the right clinical question.

SUMMARY

AMI-related cardiogenic shock preclinical models are now well established and should replace low severity AMI models. Technical and ethical constraints are not trivial, but this translational research is a key asset to build up meaningful future clinical investigations.

Science of left ventricular unloading

The concept of left ventricular unloading has its foundation in heart physiology. In fact, the left ventricular mechanics and energetics represent the cornerstone of this approach. The novel sophisticated therapies for acute heart failure, particularly mechanical circulatory supports, strongly impact on the mechanical functioning and energy consuption of the heart, ultimately affecting left ventricle loading. Notably, extracorporeal circulatory life support which is implemented for life-threatening conditions, may even overload the left heart, requiring additional unloading strategies. As a consequence, the understanding of ventricular overload, and the associated potential unloading strategies, founds its utility in several aspects of day-by-day clinical practice. Emerging clinical and pre-clinical research on left ventricular unloading and its benefits in heart failure and recovery has been conducted, providing meaningful insights for therapeutical interventions. Here, we review the current knowledge on left ventricular unloading, from physiology and molecular biology to its application in heart failure and recovery.

Transcatheter Axial Pump Use in Pediatric Patients on Veno-Arterial Extracorporeal Membrane Oxygenation: An ACTION Collaborative Experience

We report the largest pediatric multicenter experience with Impella pump use and peripheral veno-arterial extracorporeal membrane oxygenation (VA-ECMO) support. Utilizing the Advanced Cardiac Therapies Improving Outcomes Network (ACTION) collaborative database, we conducted a retrospective, multicenter study of all patients with cardiogenic shock requiring VA-ECMO support with subsequent Impella implant between October 2014 and December 2021. The primary outcome was defined as death while on Impella support. Secondary outcomes were recovery, transplantation, and transition to durable ventricular assist device (VAD) at the time of Impella explantation. Adverse events were defined according to the ACTION registry criteria. Twenty subjects were supported with Impella; Impella 2.5 (n = 3), CP (n = 12), 5.0/5.5 (n = 5). The median Interquartile range (IQR) age, weight, and body surface area at implantation were 15.6 years (IQR = 13.9-17.2), 65.7 kg (IQR = 53.1-80.7), and 1.74 m2 (IQR = 1.58-1.98). Primary cardiac diagnoses were dilated cardiomyopathy/myocarditis in nine (45%), congenital heart disease in four (20%), graft failure/rejection in four (20%), and three (15%) others. Most common adverse events included hemolysis (50%) and bleeding (20%). There were two deaths (10%) in the cohort. Nine patients (45%) were explanted for recovery, eight (40%) were transitioned to a durable VAD, and one (5%) underwent heart transplantation. Impella percutaneous pump support should be considered in the older pediatric population supported with peripheral VA-ECMO, as a means of left heart decompression, and a strategy to come off ECMO to achieve endpoints of myocardial recovery, transition to a durable VAD, or transplantation.

Hemodynamics with mechanical circulatory support devices using a cardiogenic shock model

Mechanical circulatory support (MCS) devices, including veno-arterial extracorporeal membrane oxygenation (VA-ECMO) and Impella, have been widely used for patients with cardiogenic shock (CS). However, hemodynamics with each device and combination therapy is not thoroughly understood. We aimed to elucidate the hemodynamics with MCS using a pulsatile flow model. Hemodynamics with Impella CP, VA-ECMO, and a combination of Impella CP and VA-ECMO were assessed based on the pressure and flow under support with each device and the pressure-volume loop of the ventricle model. The Impella CP device with CS status resulted in an increase in aortic pressure and a decrease in end-diastolic volume and end-diastolic pressure (EDP). VA-ECMO support resulted in increased afterload, leading to a significant increase in aortic pressure with an increase in end-systolic volume and EDP and decreasing venous reservoir pressure. The combination of Impella CP and VA-ECMO led to left ventricular unloading, regardless of increase in afterload. Hemodynamic support with Impella and VA-ECMO should be a promising combination for patients with severe CS.

Reperfusion Injury in Patients With Acute Myocardial Infarction: JACC Scientific Statement

Despite impressive improvements in the care of patients with ST-segment elevation myocardial infarction, mortality remains high. Reperfusion is necessary for myocardial salvage, but the abrupt return of flow sets off a cascade of injurious processes that can lead to further necrosis. This has been termed myocardial ischemia-reperfusion injury and is the subject of this review. The pathologic and molecular bases for myocardial ischemia-reperfusion injury are increasingly understood and include injury from reactive oxygen species, inflammation, calcium overload, endothelial dysfunction, and impaired microvascular flow. A variety of pharmacologic strategies have been developed that have worked well in preclinical models and some have shown promise in the clinical setting. In addition, there are newer mechanical approaches including mechanical unloading of the heart prior to reperfusion that are in current clinical trials.

Treatment and Care of Patients with ST-Segment Elevation Myocardial Infarction-What Challenges Remain after Three Decades of Primary Percutaneous Coronary Intervention?

Primary percutaneous coronary intervention (pPCI) has revolutionized the prognosis of ST-segment elevation myocardial infarction (STEMI) and is the gold standard treatment. As a result of its success, the number of pPCI centres has expanded worldwide. Despite decades of advancements, clinical outcomes in STEMI patients have plateaued. Out-of-hospital cardiac arrest and cardiogenic shock remain a major cause of high in-hospital mortality, whilst the growing burden of heart failure in long-term STEMI survivors presents a growing problem. Many elements aiming to optimize STEMI treatment are still subject to debate or lack sufficient evidence. This review provides an overview of the most contentious current issues in pPCI in STEMI patients, with an emphasis on unresolved questions and persistent challenges.

Novel Role for Cardiolipin as a Target of Therapy to Mitigate Myocardial Injury Caused by Venoarterial Extracorporeal Membrane Oxygenation

BACKGROUND

Cardiolipin is a mitochondrial-specific phospholipid that maintains integrity of the electron transport chain (ETC) and plays a central role in myocardial ischemia/reperfusion injury. Tafazzin is an enzyme that is required for cardiolipin maturation. Venoarterial extracorporeal membrane oxygenation (VA-ECMO) use to provide hemodynamic support for acute myocardial infarction has grown exponentially, is associated with poor outcomes, and is under active clinical investigation, yet the mechanistic effect of VA-ECMO on myocardial damage in acute myocardial infarction remains poorly understood. We hypothesized that VA-ECMO acutely depletes myocardial cardiolipin and exacerbates myocardial injury in acute myocardial infarction.

METHODS

We examined cardiolipin and tafazzin levels in human subjects with heart failure and healthy swine exposed to VA-ECMO and used a swine model of closed-chest myocardial ischemia/reperfusion injury to evaluate the effect of VA-ECMO on cardiolipin expression, myocardial injury, and mitochondrial function.

RESULTS

Cardiolipin and tafazzin levels are significantly reduced in the left ventricles of individuals requiring VA-ECMO compared with individuals without VA-ECMO before heart transplantation. Six hours of exposure to VA-ECMO also decreased left ventricular levels of cardiolipin and tafazzin in healthy swine compared with sham controls. To explore whether cardiolipin depletion by VA-ECMO increases infarct size, we performed left anterior descending artery occlusion for a total of 120 minutes followed by 180 minutes of reperfusion in adult swine in the presence and absence of MTP-131, an amphipathic molecule that interacts with cardiolipin to stabilize the inner mitochondrial membrane. Compared with reperfusion alone, VA-ECMO activation beginning after 90 minutes of left anterior descending artery occlusion increased infarct size (36±8% versus 48±7%; P<0.001). VA-ECMO also decreased cardiolipin and tafazzin levels, disrupted mitochondrial integrity, reduced electron transport chain function, and promoted oxidative stress. Compared with reperfusion alone or VA-ECMO before reperfusion, delivery of MTP-131 before VA-ECMO activation reduced infarct size (22±8%; P=0.03 versus reperfusion alone and P<0.001 versus VA-ECMO alone). MTP-131 restored cardiolipin and tafazzin levels, stabilized mitochondrial function, and reduced oxidative stress in the left ventricle.

CONCLUSIONS

We identified a novel mechanism by which VA-ECMO promotes myocardial injury and further identify cardiolipin as an important target of therapy to reduce infarct size and to preserve mitochondrial function in the setting of VA-ECMO for acute myocardial infarction.

Negative Impact of Acute Reloading after Mechanical Left Ventricular Unloading

Mechanical LV unloading for acute myocardial infarction (MI) is a promising supportive therapy to reperfusion. However, no data is available on exit strategy. We evaluated hemodynamic and cellular effects of reloading after Impella-mediated LV unloading in Yorkshire pigs. First, we conducted an acute study in normal heart to observe effects of unloading and reloading independent of MI-induced ischemic effects. We then completed an MI study to investigate optimal exit strategy on one-week infarct size, no-reflow area, and LV function with different reloading speeds. Initial studies showed that acute reloading causes an immediate rise in end-diastolic wall stress followed by a significant increase in cardiomyocyte apoptosis. The MI study did not result in any statistically significant findings; however, numerically smaller average infarct size and no-reflow area in the gradual reloading group prompt further examination of reloading approach as an important clinically relevant consideration.

Delaying reperfusion plus left ventricular unloading reduces infarct size: Sub-analysis of DTU-STEMI pilot study

INTRODUCTION

The STEMI-DTU pilot study tested the early safety and practical feasibility of left ventricular (LV) unloading with a trans-valvular pump before reperfusion. In the intent-to-treat cohort, no difference was observed for microvascular obstruction (MVO) or infarct size (IS) normalized to either the area at risk (AAR) at 3-5 days or total LV mass (TLVM) at 3-5 days We now report a per protocol analysis of the STEMI-DTU pilot study.

METHODS

In STEMI-DTU STUDY 50 adult patients (25 in each arm) with anterior STEMI [sum of precordial ST-segment elevation (ΣSTE) ≥4 mm] requiring primary percutaneous coronary intervention (PCI) were enrolled. Only patients who met all inclusion and exclusion criteria were included in this analysis. Cardiac magnetic resonance (CMR) imaging 3-5 days after PCI quantified IS/AAR and IS/TLVM and MVO. Group differences were assessed using Student's t-tests and linear regression (SAS Version-9.4).

RESULTS

Of the 50 patients enrolled, 2 died before CMR imaging. Of the remaining 48 patients those without CMR at 3-5 days (n = 8), without PCI of a culprit left anterior descending artery lesion (n = 2), with OHCA (n = 1) and with ΣSTE < 4 mm (n = 5) were removed from this analysis leaving 32/50 (64 %) patients meeting all inclusion and exclusion criteria (U-IR, n = 15; U-DR, n = 17) as per protocol. Despite longer symptom-to-balloon times in the U-DR arm (228 ± 80 vs 174 ± 59 min, p < 0.01), IS/AAR was significantly lower with 30 min of delay to reperfusion in the presence of active LV unloading (47 ± 16 % vs 60 ± 15 %, p = 0.02) and remained lower irrespective of the magnitude of precordial ΣSTE. MVO was not significantly different between groups (1.5 ± 2.8 % vs 3.5 ± 4.8 %, p = 0.15). Among patients who received LV unloading within 180 min of symptom onset, IS/AAR was significantly lower in the U-DR group.

CONCLUSION

In this per-protocol analysis of the STEMI-DTU pilot study we observed that LV unloading for 30 min before reperfusion significantly reduced IS/AAR compared to LV unloading and immediate reperfusion, whereas in the ITT cohort no difference was observed between groups. This observation supports the design of the STEMI-DTU pivotal trial and suggests that strict adherence to the study protocol can significantly influence the outcome.

Left-Ventricular Unloading With Impella During Refractory Cardiac Arrest Treated With Extracorporeal Cardiopulmonary Resuscitation: A Systematic Review and Meta-Analysis

OBJECTIVES

Extracorporeal cardiopulmonary resuscitation (ECPR) is the implementation of venoarterial extracorporeal membrane oxygenation (VA-ECMO) during refractory cardiac arrest. The role of left-ventricular (LV) unloading with Impella in addition to VA-ECMO ("ECMELLA") remains unclear during ECPR. This is the first systematic review and meta-analysis to characterize patients with ECPR receiving LV unloading and to compare in-hospital mortality between ECMELLA and VA-ECMO during ECPR.

DATA SOURCES

Medline, Cochrane Central Register of Controlled Trials, Embase, and abstract websites of the three largest cardiology societies (American Heart Association, American College of Cardiology, and European Society of Cardiology).

STUDY SELECTION

Observational studies with adult patients with refractory cardiac arrest receiving ECPR with ECMELLA or VA-ECMO until July 2023 according to the Preferred Reported Items for Systematic Reviews and Meta-Analysis checklist.

DATA EXTRACTION

Patient and treatment characteristics and in-hospital mortality from 13 study records at 32 hospitals with a total of 1014 ECPR patients. Odds ratios (ORs) and 95% CI were computed with the Mantel-Haenszel test using a random-effects model.

DATA SYNTHESIS

Seven hundred sixty-two patients (75.1%) received VA-ECMO and 252 (24.9%) ECMELLA. Compared with VA-ECMO, the ECMELLA group was comprised of more patients with initial shockable electrocardiogram rhythms (58.6% vs. 49.3%), acute myocardial infarctions (79.7% vs. 51.5%), and percutaneous coronary interventions (79.0% vs. 47.5%). VA-ECMO alone was more frequently used in pulmonary embolism (9.5% vs. 0.7%). Age, rate of out-of-hospital cardiac arrest, and low-flow times were similar between both groups. ECMELLA support was associated with reduced odds of mortality (OR, 0.53 [95% CI, 0.30-0.91]) and higher odds of good neurologic outcome (OR, 2.22 [95% CI, 1.17-4.22]) compared with VA-ECMO support alone. ECMELLA therapy was associated with numerically increased but not significantly higher complication rates. Primary results remained robust in multiple sensitivity analyses.

CONCLUSIONS

ECMELLA support was predominantly used in patients with acute myocardial infarction and VA-ECMO for pulmonary embolism. ECMELLA support during ECPR might be associated with improved survival and neurologic outcome despite higher complication rates. However, indications and frequency of ECMELLA support varied strongly between institutions. Further scientific evidence is urgently required to elaborate standardized guidelines for the use of LV unloading during ECPR.

Temporary mechanical circulatory support & enhancing recovery after cardiac surgery

PURPOSE OF REVIEW

This review highlights the integration of enhanced recovery principles with temporary mechanical circulatory support associated with adult cardiac surgery.

RECENT FINDINGS

Enhanced recovery elements and efforts have been associated with improvements in quality and value. Temporary mechanical circulatory support technologies have been successfully employed, improved, and the value of their proactive use to maintain hemodynamic goals and preserve long-term myocardial function is accruing.

SUMMARY

Temporary mechanical circulatory support devices promise to enhance recovery by mitigating the risk of complications, such as postcardiotomy cardiogenic shock, organ dysfunction, and death, associated with adult cardiac surgery.

Rationale and design of the ULYSS trial: A randomized multicenter evaluation of the efficacy of early Impella CP implantation in acute coronary syndrome complicated by cardiogenic shock

CONTEXT

Despite 20 years of improvement in acute coronary syndromes care, patients with acute myocardial infarction complicated by cardiogenic shock (AMICS) remains a major clinical challenge with a stable incidence and mortality. While intra-aortic balloon pump (IABP) did not meet its expectations, percutaneous mechanical circulatory supports (pMCS) with higher hemodynamic support, large availability and quick implementation may improve AMICS prognosis by enabling early hemodynamic stabilization and unloading. Both interventional and observational studies suggested a clinical benefit in selected patients of the IMPELLAⓇ CP device within in a well-defined therapeutic strategy. While promising, these preliminary results are challenged by others suggesting a higher rate of complications and possible poorer outcome. Given these conflicting data and its high cost, a randomized clinical trial is warranted to delineate the benefits and risks of this new therapeutic strategy.

DESIGN

The ULYSS trial is a prospective randomized open label, 2 parallel multicenter clinical trial that plans to enroll patients with AMICS for whom an emergent percutaneous coronary intervention (PCI) is intended. Patients will be randomized to an experimental therapeutic strategy with pre-PCI implantation of an IMPELLAⓇ CP device on top of standard medical therapy or to a control group undergoing PCI and standard medical therapy. The primary objective of this study is to compare the efficacy of this experimental strategy by a composite end point of death, need to escalate to ECMO, long-term left ventricular assist device or heart transplantation at 1 month. Among secondary objectives 1-year efficacy, safety and cost effectiveness will be assessed.

CLINICAL TRIAL REGISTRATION

NCT05366452.

Transvalvular Unloading Mitigates Ventricular Injury Due to Venoarterial Extracorporeal Membrane Oxygenation in Acute Myocardial Infarction

Whether extracorporeal membrane oxygenation (ECMO) with Impella, known as EC-Pella, limits cardiac damage in acute myocardial infarction remains unknown. The authors now report that the combination of transvalvular unloading and ECMO (EC-Pella) initiated before reperfusion reduced infarct size compared with ECMO alone before reperfusion in a preclinical model of acute myocardial infarction. EC-Pella also reduced left ventricular pressure-volume area when transvalvular unloading was applied before, not after, activation of ECMO. The authors further observed that EC-Pella increased cardioprotective signaling but failed to rescue mitochondrial dysfunction compared with ECMO alone. These findings suggest that ECMO can increase infarct size in acute myocardial infarction and that EC-Pella can mitigate this effect but also suggest that left ventricular unloading and myocardial salvage may be uncoupled in the presence of ECMO in acute myocardial infarction. These observations implicate mechanisms beyond hemodynamic load as part of the injury cascade associated with ECMO in acute myocardial infarction.

Left-ventricular unloading in extracorporeal cardiopulmonary resuscitation due to acute myocardial infarction - A multicenter study

BACKGROUND

Guidelines advocate the use of extracorporeal cardio-pulmonary resuscitation with veno-arterial extracorporeal membrane oxygenation (VA-ECMO) in selected patients with cardiac arrest. Effects of concomitant left-ventricular (LV) unloading with Impella® (ECMELLA) remain unclear. This is the first study to investigate whether treatment with ECMELLA was associated with improved outcomes in patients with refractory cardiac arrest caused by acute myocardial infarction (AMI).

METHODS

This study was approved by the local ethical committee. Patients treated with ECMELLA at three centers between 2016 and 2021 were propensity score (PS)-matched to patients receiving VA-ECMO based on age, electrocardiogram rhythm, cardiac arrest location and Survival After Veno-Arterial ECMO (SAVE) score. Cox proportional-hazard and Poisson regression models were used to analyse 30-day mortality rate (primary outcome), hospital and intensive care unit (ICU) length of stay (LOS) (secondary outcomes). Sensitivity analyses on patient demographics and cardiac arrest parameters were performed.

RESULTS

95 adult patients were included in this study, out of whom 34 pairs of patients were PS-matched. ECMELLA treatment was associated with decreased 30-day mortality risk (Hazard Ratio [HR] 0.53 [95% Confidence Interval (CI) 0.31-0.91], P = 0.021), prolonged hospital (Incidence Rate Ratio (IRR) 1.71 [95% CI 1.50-1.95], P < 0.001) and ICU LOS (IRR 1.81 [95% CI 1.57-2.08], P < 0.001). LV ejection fraction significantly improved until ICU discharge in the ECMELLA group. Especially patients with prolonged low-flow time and high initial lactate benefited from additional LV unloading.

CONCLUSIONS

LV unloading with Impella® concomitant to VA-ECMO therapy in patients with therapy-refractory cardiac arrest due to AMI was associated with improved patient outcomes.

Unloading the Left Ventricle in Venoarterial ECMO: In Whom, When, and How?

Venoarterial extracorporeal membrane oxygenation provides cardiorespiratory support to patients in cardiogenic shock. This comes at the cost of increased left ventricle (LV) afterload that can be partly ascribed to retrograde aortic flow, causing LV distension, and leads to complications including cardiac thrombi, arrhythmias, and pulmonary edema. LV unloading can be achieved by using an additional circulatory support device to mitigate the adverse effects of mechanical overload that may increase the likelihood of myocardial recovery. Observational data suggest that these strategies may improve outcomes, but in whom, when, and how LV unloading should be employed is unclear; all techniques require balancing presumed benefits against known risks of device-related complications. This review summarizes the current evidence related to LV unloading with venoarterial extracorporeal membrane oxygenation.

The Use of Cardioprotective Devices and Strategies in Patients Undergoing Percutaneous Procedures and Cardiac Surgery

In the United States, about one million people are seen to visit the operating theater for cardiac surgery annually. However, nearly half of these visits result in complications such as renal, neurological, and cardiac injury of varying degrees. Historically, many mechanisms and approaches have been explored in attempts to reduce injuries associated with cardiac surgery and percutaneous procedures. Devices such as cardioplegia, mechanical circulatory support, and other methods have shown promising results in managing and preventing life-threatening cardiac-surgery-related outcomes such as heart failure and cardiogenic shock. Comparably, cardioprotective devices such as TandemHeart, Impella family devices, and venoarterial extracorporeal membrane oxygenation (VA-ECMO) have also been proven to show significant cardioprotection through mechanical support. However, their use as interventional agents in the prevention of hemodynamic changes due to cardiac surgery or percutaneous interventions has been correlated with adverse effects. This can lead to a rebound increased risk of mortality in high-risk patients who undergo cardiac surgery. Further research is necessary to delineate and stratify patients into appropriate cardioprotective device groups. Furthermore, the use of one device over another in terms of efficacy remains controversial and further research is necessary to assess device potential in different settings. Clinical research is also needed regarding novel strategies and targets, such as transcutaneous vagus stimulation and supersaturated oxygen therapy, aimed at reducing mortality among high-risk cardiac surgery patients. This review explores the recent advances regarding the use of cardioprotective devices in patients undergoing percutaneous procedures and cardiac surgery.

Update on Mechanical Circulatory Support

Mechanical circulatory support (MCS) devices provide temporary or intermediate- to long-term support for acute cardiopulmonary support. In the last 20 to 30 years, tremendous growth in MCS device usage has been seen. These devices offer support for isolated respiratory failure, isolated cardiac failure, or both. Initiation of MCS devices requires the input from multidisciplinary teams using patient factors and institutional resources to guide decision making, along with a planned "exit strategy" for bridge to decision, bridge to transplant, bridge to recovery, or as destination therapy. Important considerations for MCS use include patient selection, cannulation/insertion strategies, and complications of each device.

Impact of Impella RP Versus Vasoactive Treatment on Right and Left Ventricular Strain in a Porcine Model of Acute Cardiogenic Shock Induced by Right Coronary Artery Embolization

Background The response of the left ventricle to cardiogenic shock (CS) caused by right ventricular (RV) infarction and the effect of treatment with either vasoactive treatment or Impella RP are not well described. We sought to determine RV and left ventricular longitudinal strain (LS) by echocardiography after initiation of either Impella RP or vasoactive treatment for CS induced by right coronary artery embolization. Methods and Results CS was induced with microsphere embolization in the right coronary artery in 20 pigs. Shock was defined as a reduction in cardiac output of ≥50% and/or an SvO2 <30%. At the time of CS either Impella RP or vasoactive treatment (norepinephrine and milrinone) was initiated. Echocardiography and conductance measures were obtained at baseline, when CS was present, and 30, 90, and 180 minutes after induction of CS. Of 20 animals, 14 completed the protocol and were treated with either vasoactive treatment (n=7) or Impella RP (n=7); 6 animals died (3 in each group). In the RV there was a significantly higher LS with the vasoactive treatment compared with Impella RP (-7.6% [4.5] to -6.0% [5.2] vs -4.5% [6.6] to -14.2% [10.6]; P<0.006). Left ventricular LS improved with both treatments compared with shock, but with a larger effect (-9.4% [3.2] to -17.9% [3.6]) on LS with vasoactive treatment than Impella RP (-9.8% [3.1] to -12.3% [4.6]; P<0.001). We found a significant correlation between stroke work and RV LS (r=-0.60, P<0.001) and left ventricular LS (r=-0.62, P<0.001). Conclusions We found significantly higher hemodynamic effects with vasoactive treatment compared with Impella RP in both the RV and left ventricular but at a cost of increased stroke work.

Cardiogenic shock code 2023. Expert document for a multidisciplinary organization that allows quality care

Despite the efforts made to improve the care of cardiogenic shock (CS) patients, including the development of mechanical circulatory support (MCS), the prognosis of these patients continues to be poor. In this context, CS code initiatives arise, based on providing adequate, rapid, and quality care to these patients. In this multidisciplinary document we try to justify the need to implement the SC code, defining its structure/organization, activation criteria, patient flow according to care level, and quality indicators. Our specific purposes are: a) to present the peculiarities of this condition and the lessons of infarction code and previous experiences in CS; b) to detail the structure of the teams, their logistics and the bases for the management of these patients, the choice of the type of MCS, and the moment of its implantation, and c) to address challenges to SC code implementation, including the uniqueness of the pediatric SC code. There is an urgent need to develop protocolized, multidisciplinary, and centralized care in hospitals with a large volume and experience that will minimize inequity in access to the MCS and improve the survival of these patients. Only institutional and structural support from the different administrations will allow optimizing care for CS.

Device-Based Approaches Targeting Cardioprotection in Myocardial Infarction: The Expanding Armamentarium of Innovative Strategies

Coronary reperfusion therapy has played a pivotal role for reducing mortality and heart failure after acute myocardial infarction. Although several adjunctive approaches have been studied for reducing infarct size further, both ischemia-reperfusion injury and microvascular obstruction are still major contributors to both early and late clinical events after acute myocardial infarction. The progress in the field of cardioprotection has found several promising proof-of-concept preclinical studies. However, translation from bench to bedside has not been very successful. This comprehensive review discusses the importance of infarct size as a driver of clinical outcomes post-acute myocardial infarction and summarizes recent novel device-based approaches for infarct size reduction. Device-based interventions including mechanical cardiac unloading, myocardial cooling, coronary sinus interventions, supersaturated oxygen therapy, and vagal stimulation are discussed. Many of these approaches can modify ischemic myocardial biology before reperfusion and offer unique opportunities to target ischemia-reperfusion injury.

Primary left ventricular unloading with delayed reperfusion in patients with anterior ST-elevation myocardial infarction: Rationale and design of the STEMI-DTU randomized pivotal trial

BACKGROUND

Despite successful primary percutaneous coronary intervention (PCI) in ST-elevation myocardial infarction (STEMI), myocardial salvage is often suboptimal, resulting in large infarct size and increased rates of heart failure and mortality. Unloading of the left ventricle (LV) before primary PCI may reduce infarct size and improve prognosis.

STUDY DESIGN AND OBJECTIVES

STEMI-DTU (NCT03947619) is a prospective, randomized, multicenter trial designed to compare mechanical LV unloading with the Impella CP device for 30 minutes prior to primary PCI to primary PCI alone without LV unloading. The trial aims to enroll approximately 668 subjects, with a potential sample size adaptation, with anterior STEMI with a primary end point of infarct size as a percent of LV mass evaluated by cardiac magnetic resonance at 3-5 days after PCI. The key secondary efficacy end point is a hierarchical composite of the 1-year rates of cardiovascular mortality, cardiogenic shock ≥24 hours after PCI, use of a surgical left ventricular assist device or heart transplant, heart failure, intra-cardiac defibrillator or chronic resynchronization therapy placement, and infarct size at 3 to 5 days post-PCI. The key secondary safety end point is Impella CP-related major bleeding or major vascular complications within 30 days. Clinical follow-up is planned for 5 years.

CONCLUSIONS

STEMI-DTU is a large-scale, prospective, randomized trial evaluating whether mechanical unloading of the LV by the Impella CP prior to primary PCI reduces infarct size and improves prognosis in patients with STEMI compared to primary PCI alone without LV unloading.

LPS preconditioning of MSC-CM improves protection against hypoxia/reoxygenation-induced damage in H9c2 cells partly via HMGB1/Bach1 signalling

Mesenchymal stem cell-derived conditioned medium (MSC-CM) improves cardiac function after myocardial infarction; however, this cardioprotective effect is moderate and transient. Lipopolysaccharide (LPS) pretreatment partially improves MSC-CM-mediated cardioprotective effects owing to the presence of paracrine factors. However, the mechanism underlying these improved effects remains unknown. To study the effect of LPS-pretreated MSC-CM on hypoxia/reoxygenation (H/R)-induced injury, MSCs were treated with or without LPS (400 ng/mL) for 48 h, and the supernatant was collected (MSC-CM). Subsequently, H9c2 cells were co-cultured with Nor-CM (CM derived from LPS-untreated MSCs) and LPS-CM (CM derived from LPS-pretreated MSCs) for 24 h and subjected to H/R. MSC-CM inhibited the progression of H/R-induced injury in H9c2 cells, and this protective effect was enhanced via LPS pretreatment as evidenced by the improved apoptosis assessment index (i.e. caspase-3 and B-cell lymphoma-2 [Bcl-2] expression) and decreased levels of lactic dehydrogenase (LDH) and cardiac troponin (cTn). In addition, the results of haematoxylin-eosin staining (H&E), transmission electron microscopy (TEM) and TdT-mediated dUTP nick-end labelling (TUNEL) validated that MSC-CM inhibited H/R-induced injury in H9c2 cardiomyocytes. LPS pretreatment downregulated the expression of high mobility group box-1 (HMGB1) and BTB and CNC homology-1 (Bach1) proteins in MSCs but upregulated the expression of vascular endothelial growth factor (VEGF), hepatocyte growth factor (HGF) and insulin-like growth factor (IGF). HMGB1 knockdown (MSC/siHMGB1-CM) significantly decreased the expression of Bach1 and increased the expression of VEGF, HGF and IGF. Bach1 knockdown (MSC/siBach1-CM) did not alter the production of HMGB1 but increased the expression of VEGF and IGF. LPS pretreatment did not alter the expression of the paracrine factors VEGF and HGF in the MSC/siHMGB1 group but increased their expression in the MSC/siBach1 group. The myocyte anti-apoptotic effects of MSCs/siBach1-CM were similar to those of untreated MSCs, which were not enhanced by LPS. LPS-pretreated MSC-CM protects H9c2 cells against H/R-induced injury partly through the HMGB1/Bach1 signalling pathway.

Modified Taohong Siwu decoction improves cardiac function after myocardial ischaemia and reperfusion in rats by promoting endogenous stem cell mobilization and regulating metabolites

CONTEXT

Taohong Siwu decoction (THSWD) has been shown to promote heart repair in myocardial infarction.

OBJECTIVE

To determine the effects of modified THSWD (THSWD plus four ingredients) on myocardial ischaemia and reperfusion (I/R) injury.

MATERIALS AND METHODS

Sixty Sprague-Dawley rats were randomly divided into the I/R group and three different modified THSWD dose groups (gavage administration, 1.215, 2.43, and 4.86 g, respectively). 2,3,5-Triphenyltetrazolium chloride and Evans blue staining were used to detect the infarct area at 24 h after treatment. The serum biochemical indexes and cell apoptosis were examined to determine myocardial injury. The number of endogenous stem cells, expression of stromal dell derived factor-1 (SDF-1) and stem cell factor (SCF), and cardiac function were measured at 4 weeks. The serum was collected for metabolomic analysis.

RESULTS

The high-dose modified THSWD group presented a reduced infarction area (decreased by 21.3%), decreased levels of lactate dehydrogenase and creatinine kinase, attenuated cell apoptosis, and enhanced superoxide dismutase activity in early stage I/R compared with other groups. The serum SCF and SDF-1 levels were higher in the high-dose group than in the I/R group. At 4 weeks, the infarct size and collagen content were the lowest, and the ejection fraction and fractional shortening values were the highest in the high-dose group. Moreover, high-dose modified THSWD affected the metabolism of phosphonate and phosphonate, taurine, and hypotaurine.

CONCLUSIONS

Endogenous stem cell mobilization and metabolic regulation were related to the cardioprotection of modified THSWD. We provided a new strategy and direction for the treatment of cardiovascular diseases with traditional Chinese medicine.

Cardiac fibroblasts and mechanosensation in heart development, health and disease

The term 'mechanosensation' describes the capacity of cells to translate mechanical stimuli into the coordinated regulation of intracellular signals, cellular function, gene expression and epigenetic programming. This capacity is related not only to the sensitivity of the cells to tissue motion, but also to the decryption of tissue geometric arrangement and mechanical properties. The cardiac stroma, composed of fibroblasts, has been historically considered a mechanically passive component of the heart. However, the latest research suggests that the mechanical functions of these cells are an active and necessary component of the developmental biology programme of the heart that is involved in myocardial growth and homeostasis, and a crucial determinant of cardiac repair and disease. In this Review, we discuss the general concept of cell mechanosensation and force generation as potent regulators in heart development and pathology, and describe the integration of mechanical and biohumoral pathways predisposing the heart to fibrosis and failure. Next, we address the use of 3D culture systems to integrate tissue mechanics to mimic cardiac remodelling. Finally, we highlight the potential of mechanotherapeutic strategies, including pharmacological treatment and device-mediated left ventricular unloading, to reverse remodelling in the failing heart.

Trajectories of Cardiac Function Following Treatment With an Impella Device in Patients With Acute Anterior ST-Elevation Myocardial Infarction

Background

Left ventricular (LV) unloading via the percutaneous micro-axial Impella pump is increasingly used in patients with anterior ST-segment elevation myocardial infarction (STEMI) and overt cardiogenic shock. In this context, the evolution of cardiac function and dimensions beyond hospital discharge remains uncertain. We aimed to characterize echocardiographic changes over time in patients with acute anterior STEMI treated with an Impella device.

Methods

From an ongoing prospective registry, consecutive patients with acute anterior STEMI managed with an Impella device were extracted. Transthoracic echocardiography was performed at index hospitalization and at first outpatient follow-up. Predictors of response, defined as a ≥ 10% absolute increase in left ventricular ejection fraction (LVEF) at follow-up, were sought.

Results

A total of 66 patients (89.4% male, aged 64.3 ± 11.6 years) with anterior STEMI were treated with an Impella device in the first 24 hours of hospitalization, from 2014 to 2022. In-hospital mortality was 24%. Major bleeding and vascular complications requiring surgery occurred in 24% and 11% of patients, respectively. At baseline, mean LVEF was 34% ±12%. At follow-up, survivors showed a significant increase in LVEF (P < 0.0001), whereas LV dimensions, diastolic parameters, and measures of right ventricular dimension and function remained stable. Overall, 28 patients had a ≥ 10% absolute increase in LVEF at follow-up. Baseline creatinine was the only significant predictor of response at univariate analysis.

Conclusions

Among patients with anterior STEMI requiring mechanical hemodynamic support with an Impella device, the majority of survivors showed a sustained increase in LV function, without evidence of adverse remodelling. This signal warrants further investigation in dedicated trials.

Case report: Refractory cardiac arrest supported with veno-arterial-venous extracorporeal membrane oxygenation and left-ventricular Impella CP®-Physiological insights and pitfalls of ECMELLA

INTRODUCTION

To the best of our knowledge, this is the first case report which provides insights into patient-specific hemodynamics during veno-arterio-venous-extracorporeal membrane oxygenation (VAV ECMO) combined with a left-ventricular (LV) Impella® micro-axial pump for therapy-refractory cardiac arrest due to acute myocardial infarction, complicated by acute lung injury (ALI).

PATIENT PRESENTATION

A 54-year-old male patient presented with ST-segment elevation acute coronary syndrome complicated by out-of-hospital cardiac arrest with ventricular fibrillation upon arrival of the emergency medical service. As cardiac arrest was refractory to advanced cardiac life support, the patient was transferred to the Cardiac Arrest Center for immediate initiation of extracorporeal cardiopulmonary resuscitation (ECPR) with peripheral VA ECMO and emergency percutaneous coronary intervention using drug eluting stents in the right coronary artery. Due to LV distension and persistent asystole after coronary revascularization, an Impella® pump was inserted for LV unloading and additional hemodynamic support (i.e., "ECMELLA"). Despite successful unloading by ECMELLA, post-cardiac arrest treatment was further complicated by sudden differential hypoxemia of the upper body. This so called "Harlequin phenomenon" was explained by a new onset of ALI, necessitating escalation of VA ECMO to VAV ECMO, while maintaining Impella® support. Comprehensive monitoring as derived from the Impella® console allowed to illustrate patient-specific hemodynamics of cardiac unloading. Ultimately, the patient recovered and was discharged from the hospital 28 days after admission. 12 months after the index event the patient was enrolled in the ECPR Outpatient Care Program which revealed good recovery of neurologic functions while physical exercise capacities were impaired.

CONCLUSION

A combined mechanical circulatory support strategy may successfully be deployed in complex cases of severe cardio-circulatory and respiratory failure as occasionally encountered in clinical practice. While appreciating potential clinical benefits, it seems of utmost importance to closely monitor the physiological effects and related complications of such a multimodal approach to reach the most favorable outcome as illustrated in this case.

IMPELLA VERSUS EXTRACORPOREAL MEMBRANE OXYGENATION IN CARDIOGENIC SHOCK: A SYSTEMATIC REVIEW AND META-ANALYSIS

ABSTRACT

Background: Cardiogenic shock (CS) carries high mortality. The roles of specific mechanical circulatory support (MCS) systems are unclear. We compared the clinical outcomes of Impella versus extracorporal membrane oxygenation (ECMO) in patients with CS. Methods: This is a systematic review and meta-analysis that was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta Analyses guidelines. We searched PubMed, Cochrane Central Register, Embase, Web of Science, Google Scholar, and ClinicalTrials.gov (inception through May 10, 2022) for studies comparing the outcomes of Impella versus ECMO in CS. We used random-effects models to calculate risk ratios (RRs) with 95% confidence interval (CIs). End points included in-hospital, 30-day, and 12-month all-cause mortality, successful weaning from MCS, bridge to transplant, all reported bleeding, stroke, and acute kidney injury. Results: A total of 10 studies consisting of 1,827 CS patients treated with MCS were included in the analysis. The risk of in-hospital all-cause mortality was significantly lower with Impella compared with ECMO (RR, 0.80; 95% CI, 0.65-1.00; P = 0.05), whereas there was no statistically significant difference in 30-day (RR, 0.97, 95% CI, 0.82-1.16; P = 0.77) and 12-month mortality (RR, 0.90; 95% CI, 0.74-1.11; P = 0.32). There were no significant differences between the two groups in terms of successful weaning (RR, 0.97; 95% CI, 0.81-1.15; P = 0.70) and bridging to transplant (RR, 0.88; 95% CI, 0.58-1.35; P = 0.56). There was less risk of bleeding and stroke in the Impella group compared with the ECMO group. Conclusions: In patients with CS, the use of Impella is associated with lower rates of in-hospital mortality, bleeding, and stroke than ECMO. Future randomized studies with adequate sample sizes are needed to confirm these findings.

Novel therapeutic strategies to reduce reperfusion injury after acute myocardial infarction

For almost 30 years, urgent revascularization termed primary percutaneous coronary intervention (pPCI) has been a cornerstone of modern care for acute myocardial infarction (AMI). It lowers mortality and improved cardiovascular outcome compared to conservative therapy including thrombolysis. Reperfusion injury, which occurs after successful re-opening of the formerly occluded coronary artery, had been exploited as a potential therapeutic target. When revascularisation became faster and pPCI was successfully performed within 60-90 minutes of symptom onset, the interest in a potential additive effect of targeting reperfusion injury vanished. More recently, several meta-analyses indicated that limiting reperfusion injury prevents microvascular obstruction and reduces final infarct size, thereby lowering the probability of heart failure events and improving quality of life in AMI survivors. Here, we describe the current strategies to limit reperfusion injury and to improve post-AMI outcomes such as systemic or intracoronary hypothermia, left-ventricular unloading, intracoronary infusion of super-saturated oxygen, intermittent coronary sinus occlusion, and C-reactive protein apharesis.

Mechanical Unloading of the Left Ventricle before Coronary Reperfusion in Preclinical Models of Myocardial Infarction without Cardiogenic Shock: A Meta-Analysis

Aim: to compare a conventional primary reperfusion strategy with a primary unloading approach before reperfusion in preclinical studies. Methods: we performed a meta-analysis of preclinical studies. The primary endpoint was infarct size (IS). Secondary endpoints were left ventricle end-diastolic pressure (LVEDP), mean arterial pressure (MAP), heart rate (HR), cardiac output (CO). We calculated mean differences (MDs) and associated 95% confidence intervals (CIs). Sensitivity and subgroup analyses on the primary and secondary endpoints, as well as a meta-regression on the primary endpoint using the year of publication as a covariate, were also conducted. Results: 11 studies (n = 142) were selected and entered in the meta-analysis. Primary unloading reduced IS (MD −28.82, 95% CI −35.78 to −21.86, I2 96%, p < 0.01) and LVEDP (MD −3.88, 95% CI −5.33 to −2.44, I2 56%, p = 0.02) and increased MAP (MD 7.26, 95% CI 1.40 to 13.12, I2 43%, p < 0.01) and HR (MD 5.26, 95% CI 1.97 to 8.55, I2 1%, p < 0.01), while being neutral on CO (MD −0.11, 95% CI −0.95 to 0.72, I2 88%, p = 0.79). Sensitivity and subgroup analyses showed, overall, consistent results. The meta-regression on the primary endpoint demonstrated a significant influence of the year of publication on effect estimate. Conclusions: in animal models of myocardial infarction, a primary unloading significantly reduces IS and exerts beneficial hemodynamic effects compared to a primary reperfusion.

Effect of Enalapril Combined with Bisoprolol on Cardiac Function and Inflammatory Indexes in Patients with Acute Myocardial Infarction

Objective

The use of enalapril in combination with bisoprolol in patients with acute myocardial infarction (AMI) was studied for its effect on cardiac function and inflammatory parameters.

Methods

Sixty-two cases of AMI patients admitted to our clinic from November 2019 to November 2021 were selected for the study and grouped according to the random number table method, those enrolled were given conventional treatment such as oxygenation, absolute bed rest, and sedation, and administered low molecular heparin, aspirin, atorvastatin calcium tablets, clopidogrel, and nitrates. The control group (31 cases) was treated with enalapril maleate folic acid tablets, and the treatment group (31 cases) was treated with bisoprolol fumarate tablets on top of the control group, and the efficacy, adverse effects, cardiac function, inflammatory indexes, and oxidative stress indexes of the two arms were contrasted.

Results

The incidence of adverse reactions in the therapy cohort was 12.90% higher than that in the controlled arm, but the discrepancy was not medically relevant (P < 0.05). The SOD level was larger than the concentration in the corresponding drug therapy group, and the MDA level was lower than the concentration in the respective test cases (P < 0.05); the incidence of 12.90% adverse reactions in the treatment period was lower than that of 16.13% in the specific drug therapy group, but the variance was not scientifically evident (P > 0.05).

Conclusion

Enalapril application combined with bisoprolol in AMI patients is beneficial to boost the efficacy, promote the improvement of cardiac function, reduce the inflammatory response, and improve the oxidative stress with fewer adverse effects, which can ensure the therapeutic security.

Ischemic Cardiomyopathy and Heart Failure After Acute Myocardial Infarction

Purpose of Review

Ischemic cardiomyopathy refers to systolic left ventricular dysfunction in the setting of obstructive coronary artery disease and represents the most common cause of heart failure worldwide. It is often the combination of an irreversible loss of viable mass following an acute myocardial infarction (AMI) with a dysfunctional, but still viable, myocardium in the context of a chronically reduced myocardial blood flow and reduced coronary reserve. Medical treatments aiming at modulating neurohumoral response and restoring blood flow to the ischemic cardiomyocytes were shown to dramatically abate the occurrence of ventricular dysfunction and adverse remodeling in ischemic cardiomyopathy.

Recent Findings

Novel therapeutic approaches, such as mechanical unloading and modulation of the inflammatory response, appear to be promising. Furthermore, the understanding of the mechanisms by which, despite optimal treatment, heart failure ensues after AMI, with or without adverse remodeling and systolic dysfunction, is a critical step in the search for novel ways to tackle heart failure risk beyond preservation of left ventricular volumes and systolic function.

Summary

In this review article, we explore the principal pathophysiological mechanisms and pathways of heart failure in ischemic cardiomyopathy, therapeutic opportunities, and knowledge gaps in this area.

The Effects of Ticagrelor Combined with Tirofiban on Coagulation Function, Serum Myocardial Injury Markers, and Inflammatory Factor Levels in Patients with Acute Myocardial Infarction after Percutaneous Coronary Intervention

Background

Acute myocardial infarction (AMI) refers to the acute necrosis of part of the myocardium caused by persistent and severe myocardial ischemia. This study is aimed at investigating the efficacy of tirofiban combined with ticagrelor in AMI patients after percutaneous coronary intervention (PCI) and its effects on plasma activated partial thromboplastin time (APTT), fibrinogen (FIB), D-dimer (D-D) levels, myocardial injury markers, and inflammatory factors.

Methods

68 AMI patients with AMI who received PCI were divided into control group and observation group (n =34) according to postoperative treatment methods. Both groups received ticagrelor tablets (90 mg). The observation group was additionally given tirofiban (10 μg/kg). APTT, FIB, D-D, serum myoglobin (MB), cardiac troponin I (cTnI), serum C-reactive protein (CRP), tumor necrosis factor-α (TNF-α), and IL-6, myeloperoxidase (MPO) levels and the peak time in both groups were detected. The incidence of cardiovascular events and drug safety were compared.

Results

After treatment, APTT was increased, and FIB and D-D levels were decreased in both groups. After treatment, the APTT in the observation group was longer, and FIB and D-D levels were lower than those in the control group. The peak time of serum MB and cTnI in the observation group was earlier than that in the control group. The levels of serum MB and cTnI in the observation group were lower than those in the control group. After treatment, serum CRP, TNF-α, IL-6, and MPO levels were decreased. And the incidence of cardiovascular events was reduced.

Conclusion

Tirofiban combined with ticagrelor can improve coagulation function, protect myocardium, relieve inflammation, and reduce the risk of cardiovascular events in patients with AMI after PCI.

Signaling Pathways Involved in Myocardial Ischemia-Reperfusion Injury and Cardioprotection: A Systematic Review of Transcriptomic Studies in Sus scrofa

Myocardial damage in acute myocardial infarctions (AMI) is primarily the result of ischemia−reperfusion injury (IRI). Recognizing the timing of transcriptional events and their modulation by cardioprotective strategies is critical to address the pathophysiology of myocardial IRI. Despite the relevance of pigs for translational studies of AMI, only a few have identified how transcriptomic changes shape cellular signaling pathways in response to injury. We systematically reviewed transcriptomic studies of myocardial IRI and cardioprotection in Sus scrofa. Gene expression datasets were analyzed for significantly enriched terms using the Enrichr analysis tool, and statistically significant results (adjusted p-values of <0.05) for Signaling Pathways, Transcription Factors, Molecular Functions, and Biological Processes were compared between eligible studies to describe how these dynamic changes transform the myocardium from an injured and inflamed tissue into a scar. Then, we address how cardioprotective interventions distinctly modulate the myocardial transcriptome and discuss the implications of uncovering gene regulatory networks for cardiovascular pathologies and translational applications.

Impella to Treat Acute Myocardial Infarct-Related Cardiogenic Shock

Acute myocardial infarction complicated by cardiogenic shock (AMICS), is characterized by critically low cardiac output and decreased myocardial contractility. In this situation, a treatment that unloads the myocardium and restores CO without increasing the myocardial oxygen demand is theoretically appealing. Axial flow pumps offer hemodynamic support without increasing myocardial oxygen consumption. Consequently, the use of axial flow pumps, especially the Impella devices, is increasing. It is likely that the SCAI C patient with predominantly left ventricular failure and without prolonged cardiac arrest is the best candidate for these devices. Registry data suggest that pre-PCI Impella may be advantageous to post-PCI placement. However, several gaps in knowledge exist regarding optimal patient selection, futility criteria, timing, weaning and escalation strategy, and until data from adequately sized randomized trials are available, immediate individual evaluation for mechanical circulatory support by a shock team is warranted when a patient is diagnosed with AMICS.

Percutaneous Transvalvular Microaxial Flow Pump Support in Cardiology

The Impella device (Impella, Abiomed, Danvers, MA) is a percutaneous transvalvular microaxial flow pump that is currently used for (1) cardiogenic shock, (2) left ventricular unloading (combination of venoarterial extracorporeal membrane oxygenation and Impella concept), (3) high-risk percutaneous coronary interventions, (4) ablation of ventricular tachycardia, and (5) treatment of right ventricular failure. Impella-assisted forward blood flow increased mean arterial pressure and cardiac output, peripheral tissue perfusion, and coronary blood flow in observational studies and some randomized trials. However, because of the need for large-bore femoral access (14 F for the commonly used Impella CP device) and anticoagulation, the incidences of bleeding and ischemic complications are as much as 44% and 18%, respectively. Hemolysis is reported in as many as 32% of patients and stroke in as many as 13%. Despite the rapidly growing use of the Impella device, there are still insufficient data on its effect on outcome and complications on the basis of large, adequately powered randomized controlled trials. The only 2 small and also underpowered randomized controlled trials in cardiogenic shock comparing Impella versus intra-aortic balloon pump did not show improved mortality. Several larger randomized controlled trials are currently recruiting patients or are in preparation in cardiogenic shock (DanGer Shock [Danish-German Cardiogenic Shock Trial; NCT01633502]), left ventricular unloading (DTU-STEMI [Door-To-Unload in ST-Segment-Elevation Myocardial Infarction; NCT03947619], UNLOAD ECMO [Left Ventricular Unloading to Improve Outcome in Cardiogenic Shock Patients on VA-ECMO], and REVERSE [A Prospective Randomised Trial of Early LV Venting Using Impella CP for Recovery in Patients With Cardiogenic Shock Managed With VA ECMO; NCT03431467]) and high-risk percutaneous coronary intervention (PROTECT IV [Impella-Supported PCI in High-Risk Patients With Complex Coronary Artery Disease and Reduced Left Ventricular Function; NCT04763200]).

Ventricular Unloading Using the ImpellaTM Device in Cardiogenic Shock

Cardiogenic shock (CS) remains a leading cause of hospital death. However, the use of mechanical circulatory support has fundamentally changed CS management over the last decade and is rapidly increasing. In contrast to extracorporeal membrane oxygenation as well as counterpulsation with an intraaortic balloon pump, ventricular unloading by the Impella™ device actively reduces ventricular volume as well as pressure and augments systemic blood flow at the same time. By improving myocardial oxygen supply and enhancing systemic circulation, the Impella device potentially protects myocardium, facilitates ventricular recovery and may interrupt the shock spiral. So far, the evidence supporting the use of Impella™ in CS patients derives mostly from observational studies, and there is a need for adequate randomized trials. However, the Impella™ device appears a promising technology for management of CS patients. But a profound understanding of the device, its physiologic impact and clinical application are all important when evaluating CS patients for percutaneous circulatory support. This review provides a comprehensive overview of the percutaneous assist device Impella™. Moreover, it highlights in depth the rationale for ventricular unloading in CS and describes practical aspects to optimize care for patients requiring hemodynamic support.

Intracoronary Application of Super-Saturated Oxygen to Reduce Infarct Size Following Myocardial Infarction

Optimal medical therapy for secondary prevention following acute myocardial infarction reduces non-fatal ischaemic events. Intensive antithrombotic or lipid-lowering approaches have failed to significantly lower mortality. In the past, reduction of infarct size in patients undergoing primary percutaneous revascularisation for acute myocardial infarction had been considered as a surrogate outcome marker. However, infarct size measured by magnetic resonance imaging or SPECT is strongly associated with all-cause mortality and hospitalization for heart failure within the first year after an acute myocardial infarction. Intracoronary administration of super-saturated oxygen (SSO₂) immediately after revascularisation is an approach that can be used to reduce infarct size and, therefore, improve cardiovascular outcome in patients with acute myocardial infarction. In this article, we describe the modulation of pathophysiology by SSO₂, review the existing trial data and present our first impressions with the technique in real clinical practice.

Timing of mechanical circulatory support during primary angioplasty in acute myocardial infarction and cardiogenic shock: Systematic review and meta-analysis

OBJECTIVES

We aim to define whether the timing of microaxial left ventricular assist device (IMLVAD) implantation might impact on mortality in acute myocardial infarction (AMI) cardiogenic shock (CS) patients who underwent primary percutaneous coronary intervention (PPCI).

BACKGROUND

Despite the widespread use of PPCI, mortality in patients with AMI and CS remains high. Mechanical circulatory support is a promising bridge to recovery strategy, but evidence on its benefit is still inconclusive and the optimal timing of its utilization remains poorly explored.

METHODS

We compared clinical outcomes of upstream IMLVAD use before PPCI versus bailout use after PPCI in patients with AMI CS. A systematic review and meta-analysis of studies comparing the two strategies were performed. Effect size was reported as odds ratio (OR) using bailout as reference group and a random effect model was used. Study-level risk estimates were pooled through the generic inverse variance method (random effect model).

RESULTS

A total of 11 observational studies were identified, including a pooled population of 6759 AMI-CS patients. Compared with a bailout approach, upstream IMLVAD was associated with significant reduction of 30-day (OR = 0.65; 95% confidence interval [CI] = 0.51-0.82; I²  = 43%, adjusted OR = 0.54; 95% CI = 0.37-0.59; I²  = 3%, test for subgroup difference p = 0.30), 6-month (OR = 0.51; 95% CI = 0.27-0.96; I²  = 66%), and 1-year (OR = 0.56; 95% CI = 0.39-0.79; I²  = 0%) all-cause mortality. Incidence of access-related bleeding, acute limb ischemia and transfusion outcomes were similar between the two strategies.

CONCLUSION

In patients with AMI-CS undergoing PPCI, upstream IMLVAD was associated with reduced early and midterm all-cause mortality when compared with a bailout strategy.

Poncirin ameliorates cardiac ischemia-reperfusion injury by activating PI3K/AKT/PGC-1α signaling

Poncirin, a flavonoid glycoside derivative extracted from the fruits of Poncirus trifoliata (trifoliate orange or Chinese bitter orange), has a variety of documented bioactivities, including anti-tumor, anti-inflammatory, and antioxidant effects. Oxidative stress is a major underlying factor in the pathogenesis of cardiac ischemia-reperfusion (I/R) injury. Therefore, we investigated the protective efficacy of poncirin on primary cardiomyocytes subjected to anoxia-reoxygenation (A/R) injury in vitro, and on rat hearts subjected to ischemia-reperfusion (I/R) injury in vivo. Poncirin pretreatment enhanced cardiomyocyte survival, inhibited A/R-induced oxidative stress by upregulating cellular antioxidant capacity, suppressed mitochondrial depolarization, and ultimately inhibited apoptosis. Similarly, systemic poncirin treatment significantly reduced cardiomyocyte apoptosis and infarct size in rat hearts. In addition, activity of the PI3K/AKT/PGC-1α pathway was significantly increased by poncirin pretreatment in both A/R and I/R injury models, while PI3K and PGC-1α inhibitors abolished all poncirin related effects, suggesting that this pathway is essential for the cardioprotective effects of poncirin. Pretreatment with the PGC-1α inhibitor reversed effects of poncirin without affecting p-AKT expression, indicating that PGC-1α is downstream of AKT. In conclusion, both in vitro and in vivo studies suggested that poncirin alleviates cardiac ischemia-reperfusion injury by mitigating oxidative stress, which is dependent on activation of the PI3K/AKT/PGC-1α signaling pathway.

Impaired Diastolic Function Predicts Improved Ischemic Myocardial Flow by Mechanical Left Ventricular Unloading in a Swine Model of Ischemic Heart Failure

Background: Impact of mechanical left ventricular (LV) unloading on myocardial tissue perfusion and its regulating factors remain unclear. This study was conducted to elucidate the predictors of regional blood flow (RBF) improvement by mechanical LV unloading. Materials and Methods: One to four weeks after percutaneous induction of myocardial infarction (MI), Yorkshire pigs (n = 15) underwent mechanical LV unloading using Impella CP. Hemodynamic parameters were collected prior to LV unloading. RBF in infarct, border and remote myocardium were measured by fluorescent microsphere injections before and 120 min after LV unloading. Results: RBF showed variable responses to mechanical LV unloading. While infarct RBF improved in general (0.33 ± 0.13 to 0.42 ± 0.19 mL/min/g, p = 0.06), there were a few pigs that showed little improvement. Meanwhile, there were no clear trends in the border (1.07 ± 0.47 to 1.02 ± 0.65 mL/min/g, p = 0.73) and remote myocardial RBF (1.25 ± 0.52 to 1.23 ± 0.68 mL/min/g, p = 0.85). In the simple linear regression analysis, cardiac output, mean pulmonary arterial wedge pressure, mean left atrial pressure, minimum LV pressure, end-diastolic LV pressure, maximum dP/dt, slope of end-diastolic pressure-volume relationship (EDPVR) and end-diastolic wall stress were significantly associated with % change of infarct RBF. In the multiple regression model, slope of EDPVR and maximum dP/dt remained as independent predictors of infarct RBF change. Conclusion: Steeper EDPVR and lower maximum dP/dt were associated with increased blood perfusion in the infarct area after LV unloading. Our data suggests mechanical LV unloading is more beneficial in post-MI patients with high diastolic pressure associated with increased LV stiffness and in those with worse cardiac contractility.

Mitochondrial Metabolism in Myocardial Remodeling and Mechanical Unloading: Implications for Ischemic Heart Disease

Ischemic heart disease refers to myocardial degeneration, necrosis, and fibrosis caused by coronary artery disease. It can lead to severe left ventricular dysfunction (LVEF ≤ 35–40%) and is a major cause of heart failure (HF). In each contraction, myocardium is subjected to a variety of mechanical forces, such as stretch, afterload, and shear stress, and these mechanical stresses are clinically associated with myocardial remodeling and, eventually, cardiac outcomes. Mitochondria produce 90% of ATP in the heart and participate in metabolic pathways that regulate the balance of glucose and fatty acid oxidative phosphorylation. However, altered energetics and metabolic reprogramming are proved to aggravate HF development and progression by disturbing substrate utilization. This review briefly summarizes the current insights into the adaptations of cardiomyocytes to mechanical stimuli and underlying mechanisms in ischemic heart disease, with focusing on mitochondrial metabolism. We also discuss how mechanical circulatory support (MCS) alters myocardial energy metabolism and affects the detrimental metabolic adaptations of the dysfunctional myocardium.