Left Ventricular Mechanical Unloading by Total Support of Impella in Myocardial Infarction Reduces Infarct Size, Preserves Left Ventricular Function, and Prevents Subsequent Heart Failure in Dogs

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.

Successful treatment of acute left main coronary artery disease with a drug-coated balloon under left ventricular unloading using Impella: a case report

Background

Although the efficacy and safety of drug-coated balloons (DCBs) for acute left main coronary artery (LMCA) disease have not yet been proven, stentless percutaneous coronary intervention with a DCB is preferred for patients with high bleeding risk requiring a shorter duration of dual antiplatelet therapy. Mechanical circulatory support may improve haemodynamics in patients with cardiogenic shock caused by acute LMCA disease.

Case summary

A 74-year-old man diagnosed with acute congestive heart failure underwent emergency coronary angiography (CAG) at our hospital owing to ischaemic changes on the electrocardiogram (ECG), indicating acute LMCA disease. Coronary angiography revealed severe LMCA ostial stenosis. Immediately after CAG, mechanical circulatory support was initiated using Impella CP® for haemodynamic collapse with abrupt ST-segment elevation in the precordial leads. The haemodynamics stabilized with a dramatic improvement in the ECG. We treated the culprit ostial lesion with inflation of a cutting balloon followed by DCB delivery because of an episode of haematochezia. Subsequently, his cardiac function recovered fully.

Discussion

A case of acute LMCA disease was successfully treated with a DCB under haemodynamic support using Impella CP. The left ventricular (LV) unloading with Impella was indicated to contribute to stable haemodynamics, even during long inflation with the DCB, and the immediate recovery of LV function. Haemodynamic support using Impella may be effective, especially in cases requiring repeated and longer inflation of balloon catheters accompanied by extensive myocardial ischaemia.

Review of Advancements in Managing Cardiogenic Shock: From Emergency Care Protocols to Long-Term Therapeutic Strategies

Cardiogenic shock (CS) is a complex multifactorial clinical syndrome of end-organ hypoperfusion that could be associated with multisystem organ failure, presenting a diverse range of causes and symptoms. Despite improving survival in recent years due to new advancements, CS still carries a high risk of severe morbidity and mortality. Recent research has focused on improving early detection and understanding of CS through standardized team approaches, detailed hemodynamic assessment, and selective use of temporary mechanical circulatory support devices, leading to better patient outcomes. This review examines CS pathophysiology, emerging classifications, current drug and device therapies, standardized team management strategies, and regionalized care systems aimed at optimizing shock outcomes. Furthermore, we identify gaps in knowledge and outline future research needs.

Cardioprotection in cardiovascular surgery

Since the invention of cardiopulmonary bypass, cardioprotective strategies have been investigated to mitigate ischemic injury to the heart during aortic cross-clamping and reperfusion injury with cross-clamp release. With advances in cardiac surgical and percutaneous techniques and post-operative management strategies including mechanical circulatory support, cardiac surgeons are able to operate on more complex patients. Therefore, there is a growing need for improved cardioprotective strategies to optimize outcomes in these patients. This review provides an overview of the basic principles of cardioprotection in the setting of cardiac surgery, including mechanisms of cardiac injury in the context of cardiopulmonary bypass, followed by a discussion of the specific approaches to optimizing cardioprotection in cardiac surgery, including refinements in cardiopulmonary bypass and cardioplegia, ischemic conditioning, use of specific anesthetic and pharmaceutical agents, and novel mechanical circulatory support technologies. Finally, translational strategies that investigate cardioprotection in the setting of cardiac surgery will be reviewed, with a focus on promising research in the areas of cell-based and gene therapy. Advances in this area will help cardiologists and cardiac surgeons mitigate myocardial ischemic injury, improve functional post-operative recovery, and optimize clinical outcomes in patients undergoing cardiac surgery.

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.

Ten-year trends in non-surgical patients requiring intensive care: Long-term prognostic differences by year of admission

BACKGROUND

The aim of the present study is to elucidate prognostic impact of temporal trends of non-surgical patients requiring intensive care over a 10-year period.

METHODS AND RESULTS

A total of 4276 non-surgical patients requiring intensive care from 2012 to 2021 were enrolled. Patients' backgrounds, in-hospital management, and prognoses were compared between five groups [2012-2013 (n = 825), 2014-2015 (n = 784), 2016-2017 (n = 864), 2018-2019 (n = 939), and 2020-2021 (n = 867)]. During the study period, mean age significantly increased from 69 years in 2012-2013 to 72 years in 2020-2021. Mean Acute Physiology and Chronic Health Evaluation scores significantly increased from 10 points in 2012-2013 to 12 points in 2020-2021. The median duration of intensive care unit stays increased from 3 to 4 days. Kaplan-Meier survival curve analysis showed that survival rates during 30- and 365-days were significantly lower in 2020-2021 than in 2012-2013, but it was not significantly different by a Cox proportional hazards regression model in 30 days. A Cox proportional hazards regression model revealed that the risks of 365-day all-cause death were significantly higher in patients enrolled in 2016-2017 (HR: 1.324, 95 % CI: 1.042-1.680, p = 0.021), in 2018-2019 (HR: 1.329, 95 % CI: 1.044-1.691, p = 0.021), and in 2020-2021 (HR: 1.409, 95 % CI: 1.115-1.779, p = 0.004).

CONCLUSION

The condition of patients requiring intensive care is becoming more critical year by year, leading to poorer long-term prognoses despite improvements in treatment strategies. These findings emphasize the importance of additional care management after admission into non-surgical intensive care units, particularly for the aging society of Japan.

Pharmacological inhibition of RUNX1 reduces infarct size after acute myocardial infarction in rats and underlying mechanism revealed by proteomics implicates repressed cathepsin levels

Myocardial infarction (MI) results in prolonged ischemia and the subsequent cell death leads to heart failure which is linked to increased deaths or hospitalizations. New therapeutic targets are urgently needed to prevent cell death and reduce infarct size among patients with MI. Runt-related transcription factor-1 (RUNX1) is a master-regulator transcription factor intensively studied in the hematopoietic field. Recent evidence showed that RUNX1 has a critical role in cardiomyocytes post-MI. The increased RUNX1 expression in the border zone of the infarct heart contributes to decreased cardiac contractile function and can be therapeutically targeted to protect against adverse cardiac remodelling. This study sought to investigate whether pharmacological inhibition of RUNX1 function has an impact on infarct size following MI. In this work we demonstrate that inhibiting RUNX1 with a small molecule inhibitor (Ro5-3335) reduces infarct size in an in vivo rat model of acute MI. Proteomics study using data-independent acquisition method identified increased cathepsin levels in the border zone myocardium following MI, whereas heart samples treated by RUNX1 inhibitor present decreased cathepsin levels. Cathepsins are lysosomal proteases which have been shown to orchestrate multiple cell death pathways. Our data illustrate that inhibition of RUNX1 leads to reduced infarct size which is associated with the suppression of cathepsin expression. This study demonstrates that pharmacologically antagonizing RUNX1 reduces infarct size in a rat model of acute MI and unveils a link between RUNX1 and cathepsin-mediated cell death, suggesting that RUNX1 is a novel therapeutic target that could be exploited clinically to limit infarct size after an acute MI.

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.

Current Use and Impact of Pulmonary Artery Catheters on the Short-Term Outcomes in Patients With Cardiogenic Shock Treated With an Impella: Findings From the Japan Registry for Percutaneous Ventricular Assist Device (J-PVAD)

OBJECTIVES

This study aimed to investigate the current use and impact of pulmonary artery catheters (PACs) in patients with cardiogenic shock (CS) who underwent Impella support.

DESIGN

This was a prospective multicenter observational study between January 2020 and December 2021 that registered all patients with drug-refractory acute heart failure and in whom the placement of an Impella 2.5, CP, or 5.0 pump was attempted or successful in Japan.

SETTING

Cardiac ICUs in Japan.

PATIENTS

Between January 2020 and December 2021, a total of 3112 patients treated with an Impella were prospectively enrolled in the Japan registry for percutaneous ventricular assist device (J-PVAD). Among them, 2063 patients with CS were divided into two groups according to the PAC use.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The primary endpoint was the 30-day mortality, and the secondary endpoints were hemolysis, acute kidney injury, sepsis, major bleeding unrelated to the Impella, and ventricular arrhythmias within 30 days. PACs were used in 1358 patients (65.8%) who underwent an Impella implantation. The use of venoarterial extracorporeal membrane oxygenation (VA-ECMO) was significantly higher in the patients with PACs than in those without. Factors associated with PAC use were the prevalence of hypertension, out-of-hospital cardiac arrest, New York Heart Association classification IV, the lesser prevalence of a heart rate less than 50, and the use of any catecholamine. The primary and secondary endpoints did not significantly differ according to the PAC use. Focusing on the patients with VA-ECMO use, the 30-day mortality and hemolysis were univariately lower in the patients with PACs.

CONCLUSIONS

The J-PVAD findings indicated that PAC use did not have a significant impact on the short-term outcomes in CS patients undergoing Impella support. Further prospective studies are required to explore the clinical implications of PAC-guided intensive treatment strategies in these patients.

Differential Hypoxia Risk in Cardiopulmonary Arrest Patients Undergoing Veno-Arterial Extracorporeal Membrane Oxygenation and IMPELLA Support

Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) is a therapeutic strategy for managing cardiogenic shock. However, it carries the risk of cardiogenic pulmonary edema, potentially leading to differential hypoxia. Although IMPELLA can mitigate pulmonary congestion, the combination of VA-ECMO and IMPELLA has frequently resulted in differential hypoxia, requiring a transition from VA-ECMO to veno-arteriovenous extracorporeal membrane oxygenation (VAV-ECMO). Therefore, this study aimed to examine the influence of IMPELLA on the incidence of differential hypoxia, necessitating a shift to VAV-ECMO. This single-center, retrospective, observational study included patients who experienced cardiopulmonary arrest and received treatment with VA-ECMO combined with an intra-aortic balloon pump (IABP) or IMPELLA between 2017 and 2022. The primary endpoint assessed the incidence of differential hypoxia, necessitating a switch to VAV-ECMO. Patients with cardiopulmonary arrest received treatment with VA-ECMO in combination with IABP (N = 28) or IMPELLA (N = 29). There was a significant increase in differential hypoxia 96 hours post-VA-ECMO initiation in the IMPELLA group, necessitating a transition to VAV-ECMO. The combination of VA-ECMO and IMPELLA in patients experiencing cardiopulmonary arrest may significantly increase the risk of differential hypoxia. A multidisciplinary approach employing mechanical circulatory support is crucial, with ongoing consideration of the potential risks associated with differential hypoxia.

The impact of ECPELLA on haemodynamics and global oxygen delivery: a comprehensive simulation of biventricular failure

BACKGROUND

ECPELLA, a combination of veno-arterial (VA) extracorporeal membrane oxygenation (ECMO) and Impella, a percutaneous left ventricular (LV) assist device, has emerged as a novel therapeutic option in patients with severe cardiogenic shock (CS). Since multiple cardiovascular and pump factors influence the haemodynamic effects of ECPELLA, optimising ECPELLA management remains challenging. In this study, we conducted a comprehensive simulation study of ECPELLA haemodynamics. We also simulated global oxygen delivery (DO2) under ECPELLA in severe CS and acute respiratory failure as a first step to incorporate global DO2 into our developed cardiovascular simulation.

METHODS AND RESULTS

Both the systemic and pulmonary circulations were modelled using a 5-element resistance‒capacitance network. The four ventricles were represented by time-varying elastances with unidirectional valves. In the scenarios of severe LV dysfunction, biventricular dysfunction with normal pulmonary vascular resistance (PVR, 0.8 Wood units), and biventricular dysfunction with high PVR (6.0 Wood units), we compared the changes in haemodynamics, pressure-volume relationship (PV loop), and global DO2 under different VA-ECMO flows and Impella support levels.

RESULTS

In the simulation, ECPELLA improved total systemic flow with a minimising biventricular pressure-volume loop, indicating biventricular unloading in normal PVR conditions. Meanwhile, increased Impella support level in high PVR conditions rendered the LV-PV loop smaller and induced LV suction in ECPELLA support conditions. The general trend of global DO2 was followed by the changes in total systemic flow. The addition of veno-venous ECMO (VV-ECMO) augmented the global DO2 increment under ECPELLA total support conditions.

CONCLUSIONS

The optimal ECPELLA support increased total systemic flow and achieved both biventricular unloading. The VV-ECMO effectively improves global DO2 in total ECPELLA support conditions.

Preoperative management using Impella support for acute aortic dissection with left coronary malperfusion: a case report

BACKGROUND

Acute aortic dissection (AAD) with impaired perfusion of the left coronary artery has a poor prognosis, even after urgent radical aortic surgery, due to extensive myocardial damage. Although Impella, a microaxial-flow catheter pump, is useful in managing acute myocardial infarction, it is generally contraindicated in patients with AAD because it is an intra-aortic device and the aortic structure is compromised in these cases. Here, we introduce a novel intervention that allowed a planned aortic repair after managing circulation using Impella and venoarterial extracorporeal membrane oxygenation in a case of AAD with left main trunk malperfusion.

CASE PRESENTATION

A 40-year-old man presented with cardiogenic shock. Percutaneous coronary intervention was performed to address left main trunk obstruction using an intra-aortic balloon pump; however, circulatory instability persisted. The patient was transferred to our hospital after venoarterial extracorporeal membrane oxygenation. Impella CP™ was used to improve his circulatory status. However, a subsequent CT scan confirmed an AAD diagnosis. After 5 days of stable circulatory support, the patient underwent aortic root replacement and coronary artery bypass grafting.

CONCLUSIONS

In patients with AAD and coronary malperfusion, adjunctive circulatory management with Impella may be a valuable therapeutic option.

Cardioprotective Strategies After Ischemia-Reperfusion Injury

Acute myocardial infarction (AMI) is associated with high morbidity and mortality worldwide. Although early reperfusion is the most effective strategy to salvage ischemic myocardium, reperfusion injury can develop with the restoration of blood flow. Therefore, it is important to identify protection mechanisms and strategies for the heart after myocardial infarction. Recent studies have shown that multiple intracellular molecules and signaling pathways are involved in cardioprotection. Meanwhile, device-based cardioprotective modalities such as cardiac left ventricular unloading, hypothermia, coronary sinus intervention, supersaturated oxygen (SSO2), and remote ischemic conditioning (RIC) have become important areas of research. Herein, we review the molecular mechanisms of cardioprotection and cardioprotective modalities after ischemia-reperfusion injury (IRI) to identify potential approaches to reduce mortality and improve prognosis in patients with AMI.

Late Kidney Injury After Admission to Intensive Care Unit for Acute Heart Failure

Late kidney injury (LKI) in patients with acute heart failure (AHF) requiring intensive care is poorly understood.We analyzed 821 patients with AHF who required intensive care. We defined LKI based on the ratio of the creatinine level 1 year after admission for AHF to the baseline creatinine level. The patients were categorized into 4 groups based on this ratio: no-LKI (< 1.5, n = 509), Class R (risk; ≥ 1.5, n = 214), Class I (injury; ≥ 2.0, n = 78), and Class F (failure; ≥ 3.0, n = 20). Median follow-up after admission for AHF was 385 (346-426) days. Multivariate logistic regression analysis revealed that acute kidney injury (AKI) during hospitalization (Class R, odds ratio [OR]: 1.710, 95% confidence interval [CI]: 1.138-2.571, P = 0.010; Class I, OR: 6.744, 95% CI: 3.739-12.163, P < 0.001; and Class F, OR: 9.259, 95% CI: 4.078-18.400, P < 0.001) was independently associated with LKI. Multivariate Cox regression analysis showed that LKI was an independent predictor of 3-year all-cause death after final follow-up (hazard ratio: 1.545, 95% CI: 1.099-2.172, P = 0.012). The rate of all-cause death was significantly lower in the no-AKI/no-LKI group than in the no-AKI/LKI group (P = 0.048) and in the AKI/no-LKI group than in the AKI/LKI group (P = 0.017).The incidence of LKI was influenced by the presence of AKI during hospitalization, and was associated with poor outcomes within 3 years of final follow-up. In the absence of LKI, AKI during hospitalization for AHF was not associated with a poor outcome.

Mechanical circulatory support in cardiogenic shock

Cardiogenic shock is a complex and diverse pathological condition characterized by reduced myocardial contractility. The goal of treatment of cardiogenic shock is to improve abnormal hemodynamics and maintain adequate tissue perfusion in organs. If hypotension and insufficient tissue perfusion persist despite initial therapy, temporary mechanical circulatory support (t-MCS) should be initiated. This decade sees the beginning of a new era of cardiogenic shock management using t-MCS through the accumulated experience with use of intra-aortic balloon pump (IABP) and venoarterial extracorporeal membrane oxygenation (VA-ECMO), as well as new revolutionary devices or systems such as transvalvular axial flow pump (Impella) and a combination of VA-ECMO and Impella (ECPELLA) based on the knowledge of circulatory physiology. In this transitional period, we outline the approach to the management of cardiogenic shock by t-MCS. The management strategy involves carefully selecting one or a combination of the t-MCS devices, taking into account the characteristics of each device and the specific pathological condition. This selection is guided by monitoring of hemodynamics, classification of shock stage, risk stratification, and coordinated management by the multidisciplinary shock team.

Effect of percutaneous ventricular assisted device on post-cardiac arrest myocardial dysfunction in swine model with prolonged cardiac arrest

BACKGROUND

It remains unclear if percutaneous left ventricular assist device (pLVAD) reduces post-cardiac arrest myocardial dysfunction.

METHODS

This is a prespecified analysis of a subset of swine that achieved return of spontaneous circulation (ROSC) in a study comparing pLVAD, transient aortic occlusion (AO), or both during cardiopulmonary resuscitation (CPR). Devices were initiated after 24 minutes of ventricular fibrillation cardiac arrest (8 min no-flow and 16 min mechanical CPR). AO was discontinued post-ROSC, and pLVAD support or standard care were continued. Beginning 60 minutes post-ROSC, pLVAD support was weaned to < 1.0 L/min and subsequently removed at 240 minutes. The primary outcome was cardiac index (CI), stroke volume index (SVI), and left ventricular ejection fraction (LVEF) at 240 minutes post-ROSC. Data are shown as mean (standard error).

RESULTS

Seventeen swine achieved ROSC without complication and were included in this analysis (pLVAD group, n = 11 and standard care group, n = 6). For the primary outcomes, the pLVAD group had significantly higher CI of 4.2(0.3) vs. 3.1(0.4) L/min/m2 (p = 0.043) and LVEF 60(3) vs. 49(4) % (p = 0.029) at 240 minutes after ROSC when compared with the standard care group, while SVI was not statistically significantly different (32[3] vs. 23[4] mL/min/m2, p = 0.054). During the first 60 minutes post-ROSC, the pLVAD group had significantly higher coronary perfusion pressure, lower LV stroke work index, and total pulmonary resistance index.

CONCLUSION

These results suggest that early pLVAD support after ROSC is associated with better recovery myocardial function compared to standard care after prolonged cardiac arrest.

Modification of a Transvalvular Microaxial Flow Pump for Instantaneous Determination of Native Cardiac Output and Volume

BACKGROUND

The current Impella cardiopulmonary (CP) pump, used for mechanical circulatory support in patients with cardiogenic shock (CS), cannot assess native cardiac output (CO) and left ventricular (LV) volumes. These data are valuable in facilitating device management and weaning. Admittance technology allows for accurate assessment of cardiac chamber volumes.

OBJECTIVES

This study tested the ability to engineer admittance electrodes onto an existing Impella CP pump to assess total and native CO as well as LV chamber volumes in an instantaneous manner.

METHODS

Impella CP pumps were fitted with 4 admittance electrodes and were placed in the LVs of adult swine (n = 9) that were subjected to 3 different hemodynamic conditions, including Impella CP speed adjustments, administration of escalating doses of dobutamine and microsphere injections into the left main artery to result in cardiac injury. CO, according to admittance electrodes, was calculated from LV volumes and heart rate. In addition, CO was calculated in each instance via thermodilution, continuous CO measurement, the Fick principle, and aortic velocity-time integral by means of echocardiography.

RESULTS

Modified Impella CP pumps were placed in swine LVs successfully. CO, as determined by admittance electrodes, was similar by trend to other methods of CO assessment. It was corrected for pump speed to calculate native CO, and calculated LV chamber volumes trended as expected in each experimental protocol.

CONCLUSIONS

We report, for the first time, that an Impella CP pump can be fitted with admittance electrodes and used to determine total and native CO in various hemodynamic situations.

CONDENSED ABSTRACT

Transvalvular mechanical circulatory support devices such as the Impella CP do not have the ability to provide real-time information on native cardiac output (CO) and left ventricular (LV) volumes. This information is critical in device management and in weaning in patients with cardiogenic shock. We demonstrate, for the first time, that Impella CP pumps coupled with admittance electrodes are able to determine native CO and LV chamber volumes in multiple hemodynamic situations such as Impella pump speed adjustments, escalating dobutamine administration and cardiac injury from microsphere injection.

Unexpected deformation of the right coronary artery during percutaneous coronary intervention with venoarterial extracorporeal membrane oxygenation combined with Impella: a case report

Background

The establishment of cautionary notes regarding percutaneous coronary intervention (PCI) with venoarterial extracorporeal membrane oxygenation combined with Impella (ECMELLA) is still lacking.

Case summary

A 68-year-old man was transferred to our hospital with cardiac arrest. ECMELLA insertion was performed via the bilateral femoral artery and vein for refractory ventricular fibrillation. Coronary angiography revealed an occluded lesion in the right coronary artery (RCA). Contrast injection was administered after confirming backflow through the guide catheter (GC) to avoid coronary dissection because the artery pressure was non-pulsatile during total circulation support. Prudent coronary angiography revealed a couple of accordion phenomena. Additionally, coronary angiography showed a shorter distance from the right border of the cardiac silhouette to the RCA and the venous line of extracorporeal membrane oxygenation than before PCI. This drastic change in the cardiac silhouette suggested that ECMELLA induced the collapse of the right heart system. Subsequently, a drug-eluting stent was implanted successfully. Final coronary angiography confirmed severe bending in the proximal segment of the RCA, which was absent in the reference coronary angiography. The patient had an uneventful course except for mild cognitive impairment. The computed tomography coronary angiography after ECMELLA removal indicated the RCA without deformation.

Discussion

In the present case, the collapse of the right heart system caused by ECMELLA resulted in RCA deformation. This case also underscored that contrast injection to the coronary artery in total circulation support should be administered after confirmation of backflow through a GC.

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.

Organ dysfunction, injury, and failure in cardiogenic shock

BACKGROUND

Cardiogenic shock (CS) is caused by primary cardiac dysfunction and induced by various and heterogeneous diseases (e.g., acute impairment of cardiac performance, or acute or chronic impairment of cardiac performance).

MAIN BODY

Although a low cardiac index is a common finding in patients with CS, the ventricular preload, pulmonary capillary wedge pressure, central venous pressure, and systemic vascular resistance might vary between patients. Organ dysfunction has traditionally been attributed to the hypoperfusion of the organ due to either progressive impairment of the cardiac output or intravascular volume depletion secondary to CS. However, research attention has recently shifted from this cardiac output ("forward failure") to venous congestion ("backward failure") as the most important hemodynamic determinant. Both hypoperfusion and/or venous congestion by CS could lead to injury, impairment, and failure of target organs (i.e., heart, lungs, kidney, liver, intestines, brain); these effects are associated with an increased mortality rate. Treatment strategies for the prevention, reduction, and reversal of organ injury are warranted to improve morbidity in these patients. The present review summarizes recent data regarding organ dysfunction, injury, and failure.

CONCLUSIONS

Early identification and treatment of organ dysfunction, along with hemodynamic stabilization, are key components of the management of patients with CS.

A canine model of chronic ischemic heart failure

Preclinical large animal models of chronic heart failure (HF) are crucial to both understanding pathological remodeling and translating fundamental discoveries into novel therapeutics for HF. Canine models of ischemic cardiomyopathy are historically limited by either high early mortality or failure to develop chronic heart failure. Twenty-nine healthy adult dogs (30 ± 4 kg, 15/29 male) underwent thoracotomy followed by one of three types of left anterior descending (LAD) coronary artery ligation procedures: group 1 (n = 4) (simple LAD: proximal and distal LAD ligation); group 2 (n = 14) (simple LAD plus lateral wall including ligation of the distal first diagonal and proximal first obtuse marginal); and group 3 (n = 11) (total LAD devascularization or TLD: simple LAD plus ligation of proximal LAD branches to both the right and left ventricles). Dogs were followed until chronic severe HF developed defined as left ventricular ejection fraction (LVEF) < 40% and NH2-terminal-prohormone B-type natriuretic peptide (NT-proBNP) > 900 pmol/L. Overall early survival (48-h postligation) in 29 dogs was 83% and the survival rate at postligation 5 wk was 69%. Groups 1 and 2 had 100% and 71% early survival, respectively, yet only a 50% success rate of developing chronic HF. Group 3 had excellent survival at postligation 48 h (91%) and a 100% success in the development of chronic ischemic HF. The TLD approach, which limits full LAD and collateral flow to its perfusion bed, provides excellent early survival and reliable development of chronic ischemic HF in canine hearts.NEW & NOTEWORTHY The novel total left anterior descending devascularization (TLD) approach in a canine ischemic heart failure model limits collateral flow in the ischemic zone and provides excellent early survival and repeatable development of chronic ischemic heart failure in the canine heart. This work provides a consistent large animal model for investigating heart failure mechanisms and testing novel therapeutics.

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.

Impact of extracorporeal CPR with transcatheter heart pump support (ECPELLA) on improvement of short-term survival and neurological outcome in patients with refractory cardiac arrest – A single-site retrospective cohort study

Aim

Extracorporeal cardiopulmonary resuscitation (E-CPR) using veno-arterial extracorporeal membrane oxygenation (VA-ECMO) is a novel lifesaving method for refractory cardiac arrest. Although VA-ECMO preserves end-organ perfusion, it may affect left ventricular (LV) recovery due to increased LV load. An emerging treatment modality, ECPELLA, which combines VA-ECMO and a transcatheter heart pump, Impella, can simultaneously provide circulatory support and LV unloading. In this single-site cohort study, we assessed impact of ECPELLA support on clinical outcomes of refractory cardiac arrest patients.

Method

We retrospectively reviewed 165 consecutive cardiac arrest patients, who underwent E-CPR by VA-ECMO with or without intra-aortic balloon pump (IABP) or ECPELLA from January 2012 to September 2021. We assessed 30-day survival rate, neurological outcome, hemodynamic data, and safety profiles including hemolysis, acute kidney injury, blood transfusion and embolic cerebral infarction.

Results

Among 165 E-CPR patients, 35 patients were supported by ECPELLA, and 130 patients were supported by conventional VA-ECMO with or without IABP. Following propensity score matching of 30 ECPELLA and 30 VA-ECMO patients, the 30-day survival (ECPELLA: 53%, VA-ECMO: 20%, p < 0.01) and favorable neurological outcome determined by the Cerebral Performance Category score 1 or 2 (ECPELLA: 33%, VA-ECMO: 7%, p < 0.01) were significantly higher with ECPELLA. Patients receiving ECPELLA also showed significantly higher total mechanical circulatory support flow and lower arterial pulse pressure for the first 3 days (p < 0.01) of treatment. There were no statistical differences in safety profiles between treatment groups.

Conclusion

ECPELLA may be associated with improved 30-day survival and neurological outcome in patients with refractory cardiac arrest.

Protective effect of the Impella on the left ventricular function after acute broad anterior wall ST elevation myocardial infarctions with cardiogenic shock: cardiovascular magnetic resonance imaging strain analysis

BACKGROUND

The clinical efficacy of the Impella for high-risk percutaneous coronary intervention (PCI) and cardiogenic shock remains under debate. We thus sought to investigate the protective effects on the heart with the Impella's early use pre-PCI using cardiac magnetic resonance imaging (CMRI).

METHODS

We retrospectively evaluated the difference in the subacute phase CMR imaging results (19 ± 9 days after admission) between patients undergoing an Impella (n = 7) or not (non-Impella group: n = 18 [12 intra-aortic balloon pumps (1 plus veno-arterial extracorporeal membrane oxygenation) and 6 no mechanical circulation systems]) in broad anterior ST-elevation myocardial infarction (STEMI) cases. A mechanical circulation system was implanted pre-PCI.

RESULTS

No differences were found in the door-to-balloon time, peak creatine kinase, and hospital admission days between the Impella and non-Impella groups; however, the CMRI-derived left ventricular ejection fraction was significantly greater (45 ± 13% vs. 34 ± 7.6%, P = 0.034) and end-diastolic and systolic volumes smaller in the Impella group (149 ± 29 vs. 187 ± 41 mL, P = 0.006: 80 ± 29 vs. 121 ± 40 mL, P = 0.012). Although the global longitudinal peak strain did not differ, the global radial (GRS) and circumferential peak strain (GCS) were significantly higher in the IMPELLA than non-IMPELLA group. Greater systolic and diastolic strain rates (SRs) in the Impella than non-Impella group were observed in non-infarcted rather than infarcted areas.

CONCLUSIONS

Early implantation of an Impella before PCIs for STEMIs sub-acutely prevented cardiac dysfunction through preserving the GRS, GCS, and systolic and diastolic SRs in the remote myocardium. This study provided mechanistic insight into understanding the usefulness of the Impella to prevent future heart failure.

The canine chronic atrioventricular block model in cardiovascular preclinical drug research

Ventricular cardiac arrhythmia is a life threating condition arising from abnormal functioning of many factors in concert. Animal models mirroring human electrophysiology are essential to predict and understand the rare pro- and anti-arrhythmic effects of drugs. This is very well accomplished by the canine chronic atrioventricular block (CAVB) model. Here we summarize canine models for cardiovascular research, and describe the development of the CAVB model from its beginning. Understanding of the structural, contractile and electrical remodelling processes following atrioventricular (AV) block provides insight in the many factors contributing to drug-induced arrhythmia. We also review all safety pharmacology studies, efficacy and mechanistic studies on anti-arrhythmic drugs in CAVB dogs. Finally, we compare pros and cons with other in vivo preclinical animal models. In view of the tremendous amount of data obtained over the last 100 years from the CAVB dog model, it can be considered as man's best friend in preclinical drug research. LINKED ARTICLES: This article is part of a themed issue on Preclinical Models for Cardiovascular disease research (BJP 75th Anniversary). To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v179.5/issuetoc.

Mechanical Circulatory Support in Myocardial Infarction Complicated by Cardiogenic Shock: Impact of Sex and Timing

Background

Sex differences in presentation, treatment, and outcomes persist in patients with acute myocardial infarction complicated by cardiogenic shock (AMICS). Sex-based outcomes of patients with AMICS undergoing percutaneous coronary intervention (PCI) with percutaneous left ventricular assist device (pLVAD) support are poorly defined.

Methods

From January 2017 to August 2019, consecutive patients undergoing PCI who received Impella support within 48 ​hours of myocardial infarction were enrolled in the prospective RECOVER III postmarket registry. In-hospital survival and predictors of mortality were compared by sex.

Results

A total of 358 patients (276 men and 82 women) were included. Women had lower baseline mean arterial pressure and shorter duration of pLVAD support compared with men. In-hospital adverse events were similar in women and men, including mortality (54% versus 46%, P = .25), major bleeding (11% versus 10%, P = .83), and vascular complications requiring surgery (8.5% versus 4%, P = .10). Women had better survival with pre-PCI versus post-PCI pLVAD implantation (59% versus 34%, P = .03), whereas survival in men was similar regardless of pre- versus post-PCI pLVAD support (56% versus 50%, P = .39). The number of inotrope/vasopressor use pre-pLVAD was the strongest predictor of mortality in women (OR 3.03, P = .01) but not in men (OR 1.18, P = .25).

Conclusions

Survival of patients with AMICS treated with PCI and Impella support was 52% at hospital discharge and was similar for women and men. Women with AMICS may derive greater benefit from early pLVAD support prior to escalation of inotrope/vasopressors and had no evidence of increased risk of access-related complications.

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.

Hysteretic device characteristics indicate cardiac contractile state for guiding mechanical circulatory support device use

Background

Acute heart failure and cardiogenic shock remain highly morbid conditions despite prompt medical therapy in critical care settings. Mechanical circulatory support (MCS) is a promising therapy for these patients, yet remains managed with open-loop control. Continuous measure of cardiac function would support and optimize MCS deployment and weaning. The nature of indwelling MCS provides a platform for attaining this information. This study investigates how hysteresis modeling derived from MCS device signals can be used to assess contractility changes to provide continuous indication of changing cardiac state. Load-dependent MCS devices vary their operation with cardiac state to yield a device–heart hysteretic interaction. Predicting and examining this hysteric relation provides insight into cardiac state and can be separated by cardiac cycle phases. Here, we demonstrate this by predicting hysteresis and using the systolic portion of the hysteresis loop to estimate changes in native contractility. This study quantified this measurement as the enclosed area of the systolic portion of the hysteresis loop and correlated it with other widely accepted contractility metrics in animal studies (n = 4) using acute interventions that alter inotropy, including a heart failure model. Clinical validation was performed in patients (n = 8) undergoing Impella support.

Results

Hysteresis is well estimated from device signals alone (r = 0.92, limits of agreement: − 0.18 to 0.18). Quantified systolic area was well correlated in animal studies with end-systolic pressure–volume relationship (r = 0.84), preload recruitable stroke work index (r = 0.77), and maximum slope of left ventricular pressure (dP/dt_max) (r = 0.95) across a range of inotropic conditions. Comparable results were seen in patients with dP/dt_max (r = 0.88). Diagnostic capability from ROC analysis yielded AUC measurements of 0.92 and 0.90 in animal and patients, respectively.

Conclusions

Mechanical circulatory support hysteretic behavior can be well modeled using device signals and used to estimate contractility changes. Contractility estimate is correlated with other accepted metrics, captures temporal trends that elucidate changing cardiac state, and is able to accurately indicate changes in inotropy. Inherently available during MCS deployment, this measure will guide titration and inform need for further intervention.

Interventional heart failure therapy: A new concept fighting against heart failure

Heart failure is a progressive disease that is associated with repeated exacerbations and hospitalizations. The rapid increase in the number of heart failure patients is a global health problem known as the 'heart failure pandemic'. To control the pandemic, multifaceted approaches are essential, ranging from prevention of onset to long-term disease management. Especially in patients with moderate to severe heart failure (stages C and D), surgical and catheter-based interventions are prerequisites for saving lives, preserving cardiac function, improving quality of life (QOL), and prognosis. In addition, various new medical technologies for these interventions have been clinically applied and have been shown to be effective against symptoms and improve the QOL and prognosis of patients with heart failure. Furthermore, the concept of interventional heart failure (IHF) therapy, which considers heart recovery and prevention of worsening of heart failure via multidisciplinary treatment using surgical, catheter interventions, and mechanical circulatory support devices, has been proposed worldwide. This review discusses the importance of IHF therapy in heart failure management, recent changes in interventional technologies and strategies for patients with heart failure, and worldwide education attempts for IHF specialists.

Favorable Effects of Impella on Takotsubo Syndrome Complicated with Cardiogenic Shock

Reportedly, approximately 9.9%-12.4% of patients with Takotsubo syndrome (TTS) are complicated with cardiogenic shock (CS) and its prognosis remains poor even with the support of conventional mechanical circulatory assist devices including intra-aortic balloon pumping and venoarterial extracorporeal membrane oxygenation. Impella, a novel percutaneous left ventricular assist device, provides strong circulatory support together with the unloading of the left ventricle, and it is theoretically a promising mechanical circulatory assist device for TTS. In this case study, we report four consecutive patients with TTS complicated with CS who were successfully resuscitated using the Impella support.

Temporary mechanical circulatory support in cardiogenic shock

Cardiogenic shock (CS) represents one of the foremost concerns in the field of acute cardiovascular medicine. Despite major advances in treatment, mortality of CS remains high. International societies recommend the development of expert CS centers with standardized protocols for CS diagnosis and treatment. In these terms, devices for temporary mechanical circulatory support (MCS) can be used to support the compromised circulation and could improve clinical outcome in selected patient populations presenting with CS. In the past years, we have witnessed an immense increase in the utilization of MCS devices to improve the clinical problem of low cardiac output. Although some treatment guidelines include the use of temporary MCS up to now no large randomized controlled trial confirmed a reduction in mortality in CS patients after MCS and additional research evidence is necessary to fully comprehend the clinical value of MCS in CS. In this article, we provide an overview of the most important diagnostic and therapeutic modalities in CS with the main focus on contemporary MCS devices, current state of art and scientific evidence for its clinical application and outline directions of future research efforts.

Current Landscape of Temporary Percutaneous Mechanical Circulatory Support Technology

Mechanical circulatory support devices provide hemodynamic support to patients who present with cardiogenic shock. These devices work using different mechanisms to provide univentricular or biventricular support. There is a growing body of evidence supporting use of these devices as a goal for cardiac recovery or as a bridge to definitive therapy, but definitive, well-powered studies are still needed. Mechanical circulatory support devices are increasingly used using shock team and protocols, which can help clinicians in decision making, balancing operator and institutional experience and expertise. The aim of this article is to review commercially available mechanical circulatory support devices, their profiles and mechanisms of action, and the evidence available regarding their use.

How Would the Authors Treat Their Own Temporary Left Ventricular Failure With Mechanical Circulatory Support?

In the last 20 years, mechanical circulatory supports (MCS) have overturned completely the outcomes and the clinical recovery of patients with isolated acute left ventricle failure (iALVF). This usually occurs more frequently than right-sided heart failure or biventricular dysfunction, and it mainly is caused by acute myocardial infarction. The primary role of MCS is to restore the tissue metabolism to preserve the vital organs' function but, on the other hand, they also have to relieve the workload stress on the heart. In this way, they allow not only the heart to recover from the acute event, but MCS also can stabilize the patient toward cardiac transplantation. The short-term MCS devices currently used in clinical practice are the intraaortic balloon pump, the Impella (Abiomed, Danvers, MA), and venoarterial extracorporeal membrane oxygenation (VA-ECMO), but the choice of the right and tailored device for each patient, as well as the timing to use it, is actually one of the most debated topics of MCS management.

Increased and continuous coronary arterial flow was induced by LV uncoupling condition using combined treatment of a microaxial heart pump and venoarterial extracorporeal membrane oxygenation

An emerging therapeutic modality, ECPELLA, which combines a transvalvular microaxial left ventricular (LV) assist device, Impella, and venoarterial membrane oxygenation (VA-ECMO), has been applied for patients with refractory cardiogenic shock. During ECPELLA support, VA-ECMO increases the LV load, whereas the Impella reduces the LV load. Studies reported that coronary perfusion is influenced by LV unloading conditions, and the effective degree of LV unloading to increase the coronary perfusion on ECPELLA support remains to be determined. Here, we reported a cardiogenic shock case whose coronary arterial flow was assessed by transesophageal echocardiography during ECPELLA support. The left anterior descending coronary artery (LAD) peak blood flow velocity and the velocity time integral (VTI) were not significantly increased when blood was ejected from the LV (partial LV unloading). When the LV blood ejection was completely bypassed by Impella confirmed by non-pulsatile aortic pressure with significantly reduced LV pressure with no aortic valve opening (LV uncoupling: no blood ejection from the LV), both peak velocity and VTI of the LAD were markedly increased and the blood flow became continuous throughout the cardiac cycle. Our case suggests that the coronary arterial flow in the injured myocardium is sensitive to degrees of LV unloading on ECPELLA support.

Left Ventricular Assist Devices for Acute Myocardial Infarct Size Reduction: Meta-analysis

We conducted a meta-analysis of preclinical studies that tested left ventricular assist device (LVAD) therapy for reducing myocardial infarct size in experimental acute myocardial infarction (AMI). Twenty-six articles were included with a total of 488 experimental animal subjects. The meta-analysis showed that infarct size was significantly decreased by LVAD support compared to control animals (SDM, - 2.19; 95% CI, - 2.70 to - 1.69; P < 0.001). The meta-regression analysis demonstrated a high degree of heterogeneity associated with time from coronary artery occlusion to LVAD support, which correlated positively with infarct size. Subgroup analysis suggested smaller infarct size in LVAD therapies that withdrew blood from left heart than those from right heart. The proportion of left ventricular support relative to total cardiac output was positively correlated with infarct size reduction in Impella studies. Thus, early initiation of LVAD after ischemia and effective left ventricular venting may be important factors to reduce infarct size in AMI.

Successful Treatment of Refractory Cardiogenic Shock and Electrical Storm Using the IMPELLA 5.0 with Atrial Overdrive Pacing, in a Patient with Severe Peripheral Arterial Disease

Cardiogenic shock with electrical storm is a challenging condition to manage in patients with acute myocardial infarction despite primary percutaneous coronary interventions. While active mechanical circulatory support devices may improve hemodynamics in this situation, identifying the appropriate arterial access for device deployment is difficult in patients with severe peripheral arterial disease due to severe stenosis or obstruction and tortuous path of the femoral-iliac artery or descending aorta; additionally, this also reduces the mechanical viability of the implanted circulatory support devices, thus posing a risk for limb ischemia. Herein, we report on the effectiveness of the IMPELLA 5.0, deployed via the axillary artery, in combination with atrial overdrive pacing to manage a patient with cardiogenic shock and electrical storm, without extracorporeal membrane oxygenation. Our strategy, which does not require access via the groin area, may be an attractive option for patients with severe peripheral arterial disease, particularly those with aorto-iliac occlusive disease.

Impella RP Versus Pharmacologic Vasoactive Treatment in Profound Cardiogenic Shock due to Right Ventricular Failure

The aim was to translationally compare a pharmacologic strategy versus treatment with the Impella RP in profound RV cardiogenic shock (CS). The pigs were allocated to either vasoactive therapy with norepinephrine (0.10 μg/kg/min) for the first 30 min, supplemented by an infusion of milrinone (0.4 μg/kg/min) for additional 150 min, or treatment with the Impella RP device for 180 min. Total RV workload (Pressure-volume-area × heart rate*10³(mmHg/min)) remained unaffected upon treatment with the Impella RP and increased in the vasoactive group (CS 179[147;228] to norepinephrine 268[247;306](p = 0.002 compared to Impella RP) and norepinephrine + milrinone 366[329;422] (p = 0.002 compared to Impella RP). A trend towards higher venous cerebral oxygen saturation was observed with norepinephrine than Impella RP (Impella RP 51[47;61]% vs norepinephrine 62[57;71]%; p = 0.07), which became significantly higher with the addition of milrinone (Impella RP 45[32;63]% vs norepinephrine + milrinone 73[66;81]%; p = 0.002). The Impella RP unloaded the failing RV. In contrast, vasoactive treatment led to enhanced cerebral venous oxygen saturation.

Inhaled nitric oxide preserves ventricular function during resuscitation using a percutaneous mechanical circulatory support device in a porcine cardiac arrest model: an echocardiographic myocardial work analysis

Background

Resuscitation using a percutaneous mechanical circulatory support device (iCPR) improves survival after cardiac arrest (CA). We hypothesized that the addition of inhaled nitric oxide (iNO) during iCPR might prove synergistic, leading to improved myocardial performance due to lowering of right ventricular (RV) afterload, left ventricular (LV) preload, and myocardial energetics. This study aimed to characterize the changes in LV and RV function and global myocardial work indices (GWI) following iCPR, both with and without iNO, using 2-D transesophageal echocardiography (TEE) and GWI evaluation as a novel non-invasive measurement.

Methods

In 10 pigs, iCPR was initiated following electrically-induced CA and 10 min of untreated ventricular fibrillation (VF). Pigs were randomized to either 20 ppm (20 ppm, n = 5) or 0 ppm (0 ppm, n = 5) of iNO in addition to therapeutic hypothermia for 5 h following ROSC. All animals received TEE at five pre-specified time-points and invasive hemodynamic monitoring.

Results

LV end-diastolic volume (LVEDV) increased significantly in both groups following CA. iCPR alone led to significant LV unloading at 5 h post-ROSC with LVEDV values reaching baseline values in both groups (20 ppm: 68.2 ± 2.7 vs. 70.8 ± 6.1 mL, p = 0.486; 0 ppm: 70.8 ± 1.3 vs. 72.3 ± 4.2 mL, p = 0.813, respectively). LV global longitudinal strain (GLS) increased in both groups following CA. LV-GLS recovered significantly better in the 20 ppm group at 5 h post-ROSC (20 ppm: − 18 ± 3% vs. 0 ppm: − 13 ± 2%, p = 0.025). LV-GWI decreased in both groups after CA with no difference between the groups. Within 0 ppm group, LV-GWI decreased significantly at 5 h post-ROSC compared to baseline (1,125 ± 214 vs. 1,835 ± 305 mmHg%, p = 0.011). RV-GWI was higher in the 20 ppm group at 3 h and 5 h post-ROSC (20 ppm: 189 ± 43 vs. 0 ppm: 108 ± 22 mmHg%, p = 0.049 and 20 ppm: 261 ± 54 vs. 0 ppm: 152 ± 42 mmHg%, p = 0.041). The blood flow calculated by the Impella controller following iCPR initiation correlated well with the pulsed-wave Doppler (PWD) derived pulmonary flow (PWD vs. controller: 1.8 ± 0.2 vs. 1.9 ± 0.2L/min, r = 0.85, p = 0.012).

Conclusions

iCPR after CA provided sufficient unloading and preservation of the LV systolic function by improving LV-GWI recovery. The addition of iNO to iCPR enabled better preservation of the RV-function as determined by better RV-GWI. Additionally, Impella-derived flow provided an accurate measure of total flow during iCPR.

Pump flow setting and assessment of unloading in clinical practice

The rationale for mechanical circulatory support (MCS) in cardiogenic shock is to restore cardiac output in selected patients when critically low or in case of refractory cardiac arrest. Furthermore, an MCS device that moves blood from either the left atrium or the left ventricle to the systemic circulation will potentially unload the ventricle. These devices are used alone or in combination with venoarterial extracorporeal membrane oxygenation (VA-ECMO). If a left-sided Impella device is used, it should be run at the highest possible performance level during treatment while avoiding suction events. When combined with VA-ECMO, the Impella device should be run at a lower performance level, ensuring sufficient left ventricular emptying but avoiding suction. Continuous monitoring is pivotal and patients managed outside the catheterization laboratory should be monitored with an arterial line, a central venous catheter, frequent use of pulmonary artery catheters and regular imaging by transthoracic echocardiogram.