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

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.

Quercetin in Shengxian Decoction exhibits anti-ferroptosis protective roles in a myocardial infarction model via targeting DPP4/ HMOX1, based on network pharmacology and molecular docking

Background

Myocardial infarction (MI) is characterized by high morbidity. In this study, we aimed to elucidate potential targets of Shengxian Decoction (SXD) against MI.

Methods

Pairing of SXD active ingredients and MI targets was conducted using the Chinese Medicine System Pharmacological Database, Gene Expression Omnibus (GEO), and STRING databases. The effects of SXD on MI were validated in vitro. Molecular docking was verified using cellular thermal shift assay (CETSA).

Results

A total of 40 active ingredients and 28 MI-related targets were obtained. Cross-analysis on 28 targets and cell death-related genes identified two crucial ferroptosis-related targets, namely, dipeptidyl peptidase 4 (DPP4) and heme oxygenase 1 (HMOX1). In cobalt chloride (CoCl2)-induced hypoxic H9c2 cells, SXD could remarkably improve cell viability and inhibit cell death. Meanwhile, SXD treatment significantly affected the ferroptosis-related markers in hypoxic H9c2 cells. Molecular docking and CETSA results showed that quercetin had good binding activity with DPP4 and HMOX1.

Conclusion

Important active ingredient quercetin in SXD could exert anti-ferroptosis protective roles on MI through targeting ferroptosis-related genes (DPP4/HMOX1), thereby contributing to the protective role of SXD on MI.

Early left ventricular unloading during extracorporeal membrane oxygenation in cardiogenic shock: A systematic review and meta-analysis

BACKGROUND

Left ventricular (LV) unloading is a crucial intervention to decrease the harmful consequences of extracorporeal membrane oxygenation (ECMO) on hemodynamic status in cardiogenic shock (CS) patients. However, a lingering question preoccupies experts: Should we intervene early or wait until clinical deterioration caused by increasing afterload is detected?

METHODS

A systematic review and meta-analysis synthesizing studies, which were retrieved by systematically searching PubMed, Web of Science, SCOPUS, and Cochrane through December 2023. We used R V. 4.3 to pool dichotomous data using risk ratio (RR) and continuous data using mean difference (MD) with a 95% confidence interval (CI).

PROSPERO ID

CRD42024501643.

RESULTS

Eight studies with 2.117 patients were included. Early/prophylactic LV unloading was associated with a lower incidence of all-cause mortality [RR: 0.87 with 95% CI (0.79, 0.95), p < 0.01]. However, there was no significant difference between the two groups regarding cardiac mortality [RR: 1.01 with 95% CI (0.68, 1.48), p = 0.98], non-cardiac mortality [RR: 0.86 with 95% CI (0.46, 1.62), p = 0.64], and in-hospital mortality [RR: 0.95 with 95% CI (0.86, 1.05), p = 0.30]. There was no significant difference between the two groups regarding ECMO weaning, myocardial recovery, ECMO duration, and length of hospitalization.

CONCLUSION

Early/prophylactic LV unloading during ECMO for CS patients was associated with a decreased incidence of all-cause mortality and sepsis or infection, with no effect on ECMO weaning, myocardial recovery, ECMO duration, and hospital length of stay.

Comparison of mechanical resuscitation by an LV Impella device to extracorporeal resuscitation using VAECMO in a large animal model

Extracorporeal cardiopulmonary resuscitation (ECPR) is an effective treatment for cardiac arrest (CA). Percutaneous left ventricular (LV) assist devices such as the Impella ECP (intravascular CPR [ICPR]) have been proposed as a less invasive alternative. The aim of this study was to explore the haemodynamic differences between ECPR and ICPR using a large animal model of electrically induced CA. Fourteen juvenile female German landrace pigs (72.4 ± 9.8 kg) were subjected to electrically induced CA for 5 mins followed by either ECPR (veno-arterial extracorporeal membrane oxygenation [VA-ECMO]) or ICPR (Impella ECP). Haemodynamic parameters and echocardiographic ventricular function indicators were monitored. Mechanical circulatory support (MCS) was continued until five hours after the return of spontaneous circulation (ROSC), when the devices were removed. Resuscitation outcomes and the haemodynamic effects of ECPR and ICPR were compared. The cannulation time for ECMO (469 ± 129 s) was significantly longer than the time for Impella device implantation (153 ± 64 s, p < 0.001). ECPR facilitated ROSC in 6/6 animals, whereas ICPR facilitated ROSC in 6/8 animals (p = 0.19). Echocardiography revealed no difference in LV or right ventricular (RV) dysfunction between the ECPR- and ICPR-treated animals after resuscitation (LV-global longitudinal strain [GLS] 3 h post-ROSC: ICPR: - 16.5 ± 5.6% vs. ECPR: - 13.7 ± 5.9%, p = 0.99; RV-GLS 3 h post-ROSC: ICPR: - 15.9 ± 3.3% vs. ECPR: - 17.3 ± 10.6%, p = 0.99). MCS using VA-ECMO and the Impella device both provided effective haemodynamic support during CA and post-ROSC in this large animal model. Despite LV unloading conferring a hypothetical advantage for ICPR, no significant differences in myocardial recovery were observed.

Impact of Prereperfusion Left Ventricle Unloading on ST-Segment Elevation Myocardial Infarction According to the Onset-to-Unloading Time

It is unclear whether the impact of prereperfusion unloading on improving survival is sustained throughout all periods from the onset in patients with ST-segment elevation myocardial infarction. This study is a post hoc analysis of the Japanese registry for Pectaneous Ventricular Assist Device (J-PVAD) registry. In all patients registered in J-PVAD between February 2020 and December 2021, patients with ST-segment elevation myocardial infarction complicated with cardiogenic shock and treated with Impella support alone were selected. A total of 2 cohorts were provided based on whether the onset-to-unloading time was <6 hours. The patients were divided into 2 groups according to prereperfusion or postreperfusion unloading in each cohort. The primary outcome was the 30-day survival rate. The independent factors of survival were identified with a multivariable Cox proportional hazard regression analysis after adjusting for the variables that were statistically significant in the univariable analysis. Patients with prereperfusion unloading had a significantly higher 30-day survival rate than patients with postreperfusion unloading (91% vs 67%, p <0.01) in the cohort with an onset-to-unloading time ≥6 hours, whereas patients with prereperfusion or postreperfusion unloading had similar 30-day survival rates (88% vs 91%, p = 0.64) in the cohort with an onset-to-unloading time <6 hours. A multivariable analysis revealed that prereperfusion use of Impella was an independent factor of survival (hazard ratio 0.249, 95% confidence interval 0.070 to 0.889, p = 0.03) in the onset-to-unloading time ≥6 hours cohort. In conclusion, prereperfusion left ventricular unloading could be a crucial treatment to improve the short-term survival rate when the onset-to-left ventricular unloading time was ≥6 hours.

Multi-dimensional outcomes following extracorporeal cardiopulmonary resuscitation

Background

Recent trials suggested that extracorporeal cardio-pulmonary resuscitation (ECPR) with veno-arterial extracorporeal membrane oxygenation (VA-ECMO) or "ECMELLA" (VA-ECMO plus Impella®) may improve short-term survival and neurological outcomes in selected patients with refractory cardiac arrest. However, long-term effects on cardiac, cognitive, physical and psychological health need further study. A multidisciplinary post-ECPR outpatient care program was developed at two centers, involving cardiologists, neurologists, psychologists and medical sociologists to assess seven key health dimensions.

Methods

This bicentric, multidisciplinary study, conducted from May 2021 to April 2023, included adult ECPR survivors. Outcomes were assessed approximately 22 months post-cardiac arrest, focusing on cardiac, neurological, psychological and multi-organ functions, as well as social, professional and physical performance.

Results

This study included 33 ECPR survivors, who were predominantly male (70%) with a mean age of 55 years. Left-ventricular ejection fraction improved significantly, from 22% during ICU stay to 51% at follow-up in the ECMELLA group and from 31% to 51% in the VA-ECMO group (p = 0.006). Many patients reported dizziness or dyspnea (>52%) during daily activities, with a median New York Heart Association class of 2, EQ-5D-5L score of 53 and elevated NT-proBNP levels. Despite normal neurological scores, 46% had memory issues, 39% struggled with daily organization, 52% had depression and 12% had suicidal thoughts. Physical performance was reduced, with a mean distance of 394 meters in the 6-minute walk test and a 6-minute bicycle ergometry time.

Conclusion

ECPR patients showed significant improvement in left ventricular function over time but their neuropsychological and physical abilities remained compromised. Timely, multidisciplinary rehabilitation is required, starting in the intensive care unit and extending to include psychological support and community reintegration strategies after discharge.

Left Ventricular Unloading Using Intra-aortic Entrainment Pumping Before Reperfusion Reduces Post-AMI Infarct Size

BACKGROUND

Anterior myocardial infarction standard of care prioritizes swift coronary reperfusion. Recent studies show left ventricular (LV) unloading with transvalvular axial flow pumps for 30 minutes before reperfusion (vs immediate reperfusion) decreases 28-day infarct size. Intra-aortic entrainment pumping, using hardware located away from the heart to provide support throughout the cardiac cycle, decreases effective systemic vascular resistance and augments visceral blood flow and pressure, and may reproduce this benefit with a decreased risk. This study characterized the hemodynamic effects of unloading before and during reperfusion using intra-aortic entrainment pumping and investigated whether unloading decreased anterior myocardial infarction scar size.

METHODS AND RESULTS

Yorkshire swine were subjected to 90 minutes of left anterior descending artery balloon occlusion and randomly assigned to immediate reperfusion (n = 6) vs 30 minutes unloading before reperfusion followed by 120 minutes of further unloading (n = 7). Unloading was achieved using percutaneous entrainment pumping in the descending aorta. The anterior myocardial infarction model matches that used in recent transvalvular pumping studies. Mortality before randomization was 22%. After randomization, mortality was 36% for immediate reperfusion and 0% for unloading. Unloading showed immediate hemodynamic benefit that increased through reperfusion and continued support, leading to distinct differences in cardiac function between groups after 30 minutes of reperfusion. Unloading increased stroke volume and cardiac efficiency at this timepoint relative to preocclusion baseline and reduced 28-day LV scar size by 37%-45%.

CONCLUSIONS

We present the first preclinical data showing extracardiac LV unloading before coronary reperfusion using intra-aortic entrainment pumping decreases 28-day infarct size. Extracardiac unloading to decrease LV scar size may provide an alternative to transvalvular pumping with potential advantages, including reduced risk.

Early unloading and clinical outcomes in patients with fulminant myocarditis undergoing VA-ECMO: results of a multicenter retrospective study

INTRODUCTION AND OBJECTIVES

Although venoarterial extracorporeal membrane oxygenation (VA-ECMO) provides effective cardiocirculatory support in patients with fulminant myocarditis, the most effective timing of venting is uncertain. We aimed to investigate the benefit of early venting among patients who underwent VA-ECMO for fulminant myocarditis.

METHODS

Among 841 patients with acute myocarditis from 7 hospitals in the Republic of Korea, 217 patients with fulminant myocarditis who underwent VA-ECMO were included in this analysis. The patients were categorized into 2 groups: an early unloading group that underwent venting within 24hours of ECMO insertion, and the no or delayed unloading group. The primary outcome was a composite of death, cardiac replacement, or cardiovascular rehospitalization.

RESULTS

Among 217 patients, 56 underwent early venting, 54 underwent delayed venting, and 107 did not undergo venting. On spline curves in 110 patients who underwent venting, rapid deterioration was observed as the timing of venting was delayed. The incidence of the primary outcome was lower in the early venting group than in the no or delayed unloading group (37.5% vs 58.4%; HR, 0.491; 95%CI, 0.279-0.863; P=.014). Among patients not experiencing the primary outcome within 6 months, clinical outcomes were similar after 6 months (P=.375).

CONCLUSIONS

Early left heart unloading within 24hours of ECMO insertion is associated with a lower risk of a composite of death, cardiac replacement therapy, and cardiovascular rehospitalization in patients with fulminant myocarditis undergoing VA-ECMO. Registered at ClinicalTrials.gov (NCT05933902).

Peroxisome proliferator-activated receptor gamma ( PPARG )-mediated myocardial salvage in acute myocardial infarction managed with left ventricular unloading and coronary reperfusion

Ischemic heart disease and acute myocardial infarction (AMI) is a leading cause of morbidity and mortality. Improvements have been made in coronary interventions to restore blood flow, but ischemia/reperfusion (I/R) injury significantly impacts clinical outcomes. We previously reported that activation of percutaneous mechanical unloading of the left ventricle (LV) with a transvalvular axial-flow device simultaneously with reperfusion improves myocardial salvage. However, the underlying mechanisms, potential adjuvant pharmacological interventions and the timing of the use of LV unloading as a cardioprotective approach in AMI are not well understood. This study investigated a) the mechanisms associated with improved myocardial salvage, b) a pharmacological intervention, and c) the timing of LV unloading. Following 90 minutes of ischemia, adult swine were subjected to reperfusion alone, simultaneous unloading with reperfusion, upfront unloading with delayed reperfusion, upfront reperfusion with delayed unloading, or reperfusion with concurrent use of esmolol and milrinone. Compared to controls, the simultaneous group had a 47% increase in myocardial salvage following AMI. This was associated with increased expression of neutrophil degranulation, macrophage activation, iNOS signaling, wound healing, and PPAR signaling. From these pathways, PPARG (peroxisome proliferator-activated receptor gamma) emerged as a potential cardioprotective gene that was uniquely overexpressed in the simultaneously unloaded and reperfused myocardium. Next, we showed PPARG agonism with rosiglitazone reduces mitochondrial oxygen demand in cardiomyocytes and in vivo, improves myocardial salvage following I/R injury in C57BL6/J mice. Thiazolidinediones (TZDs), such as rosiglitazone could be investigated as therapies combined with simultaneous LV unloading and coronary interventions to mitigate reperfusion injury.

GRAPHICAL ABSTRACT

Impact of lactate levels on admission in STEMI patients with cardiogenic shock treated with IMPELLA

The concomitant use of IMPELLA and veno-arterial extracorporeal membrane oxygenation (V-A ECMO) (ECPELLA) has been increasingly used to treat severe cardiogenic shock. However, the relationship between severity of heart failure on admission and prognosis based on differences in the mechanical circulatory support (MCS) is not fully understood. This study evaluated the association between lactate levels on admission and clinical outcomes based on differences in MCS. We identified 852 patients (median age 71 years; 78% male) with cardiogenic shock due to ST-elevation myocardial infarction (STEMI) from the Japanese Registry for Percutaneous Ventricular Assist Devices. The primary endpoint was the in-hospital mortality rate. Additionally, patients were classified into three groups based on lactate levels according to the SCAI SHOCK classification for the assessment of in-hospital mortality: group 1 (lactate level < 2 mmol/L), group 2 (lactate level 2-8 mmol/L), and group 3 (lactate level ≥ 8 mmol/L). The in-hospital mortality rate was 41.8%. The rate of V-A ECMO combined with IMPELLA use was 37.6%. The in-hospital mortality rates of the IMPELLA alone and ECPELLA group were 30.1% and 61.3%, respectively. The median lactate level was significantly higher in non-survivors than in survivors (5.7 mmol/L vs. 3.5 mmol/L, p < 0.0001). The in-hospital mortality rate with IMPELLA alone was significantly higher in group 3 compared to groups 1 and 2; however, there was no difference in in-hospital mortality with ECPELLA among the three groups. A lactate cut-off value of 6.9 mmol/L showed the best discrimination for in-hospital mortality. Patients classified as the SCAI SHOCK stage E have a higher mortality rate with IMPELLA support alone. Further research is needed to optimize management strategies for this high-risk group.

Predictive models of in-hospital deterioration of Society of Cardiovascular Angiography and Intervention shock stage in patients with acute myocardial infarction initially presenting with stable hemodynamic condition

Background

The Society of Cardiovascular Angiography and Intervention (SCAI) has defined 5 stages of cardiogenic shock (CS). In patients with acute myocardial infarction (AMI) who initially present in stable hemodynamic condition (SCAI CS stage: A or B), CS stages could deteriorate despite therapeutic management. However, deterioration of SCAI CS stages after AMI remains to be fully characterized. Therefore, the current study sought to investigate the frequency and clinical characteristics about deterioration of SCAI CS stages after AMI.

Methods

We retrospectively analyzed 347 patients in a derivation cohort and 163 patients in a validation cohort who had AMI (SCAI shock stage upon arrival: A/B) and underwent percutaneous coronary intervention (PCI) at National Cerebral and Cardiovascular Center, Suita, Japan (enrolment period of study subjects: 2019.07.01-2022.09.30). Deterioration of CS (D-CS) was defined as SCAI shock stage C-E after PCI. Clinical characteristics and in-hospital mortality were compared according to D-CS status. Adjusted hazard ratios (HRs) for in-hospital mortality were calculated with multivariate Cox proportional hazards models that included variables with P<0.10 in univariate models. Uni- and multivariate logistic regression analyses were used to identify predictors of D-CS.

Results

D-CS occurred in 17.3% (60/347) of the derivation cohort. Patients with D-CS had lower systolic blood pressure (BP) (P<0.001) and left ventricular ejection fraction (LVEF) (P<0.001) upon arrival with a higher proportion of initial Thrombolysis in Myocardial Infarction (TIMI) grade flow 0 or 1 (P=0.002). During hospitalization (13.9±9.4 days), D-CS was associated with higher in-hospital mortality [adjusted HR, 12.95; 95% confidence interval (CI): 1.46-114.97; P=0.02]. Initial systolic BP, LVEF, and TIMI grade flow 0 or 1 independently predicted D-CS. The D-CS risk score including these variables satisfactorily predicted D-CS [area under the curve (AUC), 0.749; 95% CI: 0.651-0.848] and in-hospital mortality (AUC, 0.961; 95% CI: 0.914-1.000) in the validation cohort.

Conclusions

D-CS occurred in 17.3% of patients with AMI initially presenting in stable condition and increased the risk of in-hospital mortality. Our D-CS risk score (initial systolic BP, LVEF, and TIMI grade flow) could be helpful to predict D-CS.

Animal Models for Mechanical Circulatory Support: A Research Review

Heart failure is a clinical syndrome that has become a leading public health problem worldwide. Globally, nearly 64 million individuals are currently affected by heart failure, causing considerable medical, financial, and social challenges. One therapeutic option for patients with advanced heart failure is mechanical circulatory support (MCS) which is widely used for short-term or long-term management. MCS with various ventricular assist devices (VADs) has gained traction in end-stage heart failure treatment as a bridge-to-recovery, -decision, -transplant or -destination therapy. Due to limitations in studying VADs in humans, animal studies have substantially contributed to the development and advancement of MCS devices. Large animals have provided an avenue for developing and testing new VADs and improving surgical strategies for VAD implantation and for evaluating the effects and complications of MCS on hemodynamics and organ function. VAD modeling by utilizing rodents and small animals has been successfully implemented for investigating molecular mechanisms of cardiac unloading after the implantation of MCS. This review will cover the animal research that has resulted in significant advances in the development of MCS devices and the therapeutic care of advanced heart failure.

Temporary mechanical circulatory support in infarct-related cardiogenic shock: an individual patient data meta-analysis of randomised trials with 6-month follow-up

BACKGROUND

Percutaneous active mechanical circulatory support (MCS) devices are being increasingly used in the treatment of acute myocardial infarction-related cardiogenic shock (AMICS) despite conflicting evidence regarding their effect on mortality. We aimed to ascertain the effect of early routine active percutaneous MCS versus control treatment on 6-month all-cause mortality in patients with AMICS.

METHODS

In this individual patient data meta-analysis, randomised controlled trials of potential interest were identified, without language restriction, by querying the electronic databases MEDLINE via PubMed, Cochrane Central Register of Controlled Trials, and Embase, as well as ClinicalTrials.gov, up to Jan 26, 2024. All randomised trials with 6-month mortality data comparing early routine active MCS (directly in the catheterisation laboratory after randomisation) versus control in patients with AMICS were included. The primary outcome was 6-month all-cause mortality in patients with AMICS treated with early routine active percutaneous MCS versus control, with a focus on device type (loading, such as venoarterial extracorporeal membrane oxygenation [VA-ECMO] vs unloading) and patient selection. Hazard ratios (HRs) of the primary outcome measure were calculated using Cox regression models. This study is registered with PROSPERO, CRD42024504295.

FINDINGS

Nine reports of randomised controlled trials (n=1114 patients) were evaluated in detail. Overall, four randomised controlled trials (n=611 patients) compared VA-ECMO with a control treatment and five randomised controlled trials (n=503 patients) compared left ventricular unloading devices with a control treatment. Two randomised controlled trials also included patients who did not have AMICS, who were excluded (55 patients [44 who were treated with VA-ECMO and 11 who were treated with a left ventricular unloading device]). The median patient age was 65 years (IQR 57-73); 845 (79·9%) of 1058 patients with data were male and 213 (20·1%) were female. No significant benefit of early unselected MCS use on 6-month mortality was noted (HR 0·87 [95% CI 0·74-1·03]; p=0·10). No significant differences were observed for left ventricular unloading devices versus control (0·80 [0·62-1·02]; p=0·075), and loading devices also had no effect on mortality (0·93 [0·75-1·17]; p=0·55). Patients with ST-elevation cardiogenic shock without risk of hypoxic brain injury had a reduction in mortality with MCS use (0·77 [0·61-0·97]; p=0·024). Major bleeding (odds ratio 2·64 [95% CI 1·91-3·65]) and vascular complications (4·43 [2·37-8·26]) were more frequent with MCS use than with control.

INTERPRETATION

The use of active MCS devices in patients with AMICS did not reduce 6-month mortality (regardless of the device used) and increased major bleeding and vascular complications. However, patients with ST-elevation cardiogenic shock without risk of hypoxic brain injury had a reduction in mortality after MCS use. Therefore, the use of MCS should be restricted to certain patients only.

FUNDING

The Heart Center Leipzig at Leipzig University and the Foundation Institut für Herzinfarktforschung.

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.

Management of Myocardial Infarction: Emerging Paradigms for the Future

Despite significant advancements in managing acute ST-segment elevation myocardial infarctions, the prevalence of heart failure has not decreased. Emerging paradigms with a focus on reducing infarct size show promising evidence in the improvement of the incidence of heart failure after experiencing acute coronary syndromes. Limiting infarct size has been the focus of multiple clinical trials over the past decades and has led to left ventricular (LV) unloading as a potential mechanism. Contemporary use of microaxial flow devices for LV unloading has suggested improvement in mortality in acute myocardial infarction complicated by cardiogenic shock. This review focuses on clinical data demonstrating evidence of infarct size reduction and highlights ongoing clinical trials that provide a new therapeutic approach to the management of acute myocardial infarction.

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.

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.

Role of Mechanical Circulatory Support in Acute MI Management

Cardiogenic shock complicating acute MI carries high mortality and morbidity in many cases. Mechanical circulatory support devices are often used in these cases, aimed at improving patient-centered outcomes, although there is a lack of large randomized clinical trial-based evidence for many of such devices. Various circulatory support devices are available with their associated risks and benefits. Ideal circulatory support device intends to unload the myocardium, halt the spiral of ischemia, provide support for revascularization, and/or allow time for myocardial recovery. In this review paper, the commonly used mechanical circulatory support devices available for use in acute myocardial infarction settings are discussed, and the pros and cons of these devices are examined, considering the contemporary data for each. While this is an evolving field, the authors believe this paper can be helpful to review the current status of the use of mechanical support devices in the setting of acute MI and highlight some of the unmet needs in this field.

Prognostic Impact of Prehospital Simple Risk Index in Patients With ST-Elevation Myocardial Infarction

BACKGROUND

The simple risk index recorded in the emergency room (ER-SRI), which is calculated using the formula (heart rate × [age / 10]2) / systolic blood pressure, was shown to be able to stratify the prognosis in ST-elevation myocardial infarction (STEMI) patients. However, the prognostic impact of the prehospital simple risk index (Pre-SRI) remains unknown.

METHODS AND RESULTS

This study enrolled 2,047 STEMI patients from the Mie Acute Coronary Syndrome (ACS) registry. Pre-SRI was calculated using prehospital data and ER-SRI was calculated using emergency room data. The primary endpoint was 30-day all-cause mortality. The cut-off values of Pre-SRI and ER-SRI for predicting 30-day mortality were 34.8 and 34.1, with accuracies of 0.816 and 0.826 based on receiver operating characteristic analyses (P<0.001 for both). There was no difference in the accuracy of the 2 indices. Multivariate Cox regression analysis demonstrated that a High Pre-SRI (≥34) was a significant independent predictor of 30-day mortality. With combined Pre-SRI and ER-SRI assessment, patients with High Pre-SRI/High ER-SRI showed significantly higher mortality than those with High Pre-SRI/Low ER-SRI, Low Pre-SRI/High ER-SRI, and Low Pre-SRI/Low ER-SRI (P<0.001). The addition of High Pre-SRI to High ER-SRI showed incremental prognostic value of the Pre-SRI.

CONCLUSIONS

Pre-SRI can identify high-risk STEMI patients at an early stage and combined assessment with Pre-SRI and ER-SRI could be of incremental prognostic value for risk stratification in STEMI patients.

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.