Use of the AB5000™ Ventricular Assist Device in Cardiogenic Shock After Acute Myocardial Infarction

Temporary Mechanical Circulatory Support in Acute Heart Failure

Cardiogenic shock (CS) is a challenging syndrome, associated with significant morbidity and mortality. Although pharmacological therapies are successful and can successfully control this acute cardiac illness, some patients remain refractory to drugs. Therefore, a more aggressive treatment strategy is needed. Temporary mechanical circulatory support (TCS) can be used to stabilise patients with decompensated heart failure. In the last two decades, the increased use of TCS has led to several kinds of devices becoming available. However, indications for TCS and device selection are part of a complex process. It is necessary to evaluate the severity of CS, any early and prompt haemodynamic resuscitation, prior TCS, specific patient risk factors, technical limitations and adequacy of resources and training, as well as an assessment of whether care would be futile. This article examines options for commonly used TCS devices, including intra-aortic balloon pumps, a pulsatile percutaneous ventricular assist device (the iVAC), veno-arterial extra-corporeal membrane oxygenation and Impella (Abiomed) and TandemHeart (LivaNova) percutaneous ventricular assist device.

Outcomes of Impella 5.0 in Cardiogenic Shock

Objective

The aim of the study was to comprehensively summarize the survival outcomes and complications of Impella 5.0 (Abiomed Inc, Danvers, MA USA) use in patients with cardiogenic shock (CS).

Methods

We performed a literature review for relevant studies by searching in Medline, Medline In-Process, EMBASE, and the CENTRAL bibliographic databases on April 30, 2017. Nonoverlapping studies with 10 patients or more supported for cardiogenic shock with Impella 5.0 or Impella left direct were included. Data on patient characteristics, indication of support, and outcomes were extracted. A random effect was used to pool the various outcomes.

Results

This meta-analysis included six studies totaling 163 patients (mean ± SD age = 56.3 ± 12.0, male 81%). Indications for support included 88 (54.0%) for acute on chronic decompensated heart failure, 35 (21.5%) for postcardiotomy cardiogenic shock, 27 (16.6%) for acute myocardial infarction complicated by cardiogenic shock, and, 13 (8.0%) for cardiogenic shock due to other reasons. Survival to next therapy was 73.5% in patients supported for acute on chronic decompensated heart failure. The survival to device explant among patients supported for postcardiotomy cardiogenic shock or acute myocardial infarction complicated by cardiogenic shock was 90.2%, and of those, myocardial recovery was achieved in 73.8%. The overall estimated survival to discharge, 30, 180, and 365 days was 73.5%, 72.6%, 62.7%, and 58.4%, respectively. Patients supported for postcardiotomy cardiogenic shock had the highest heart recovery among survivors to explant (92.1%) and highest survival at 30 (89.5%) and 365 days (69.5%).

Conclusions

Impella 5.0/LD is associated with favorable survival outcomes and higher rate of myocardial recovery in patients with cardiogenic shock.

The AB Portable Driver Generates Higher Drive-Line Pressures Possibly Leading to Accelerated Hemolysis

The AB5000 Circulatory Support System is paracorporeal pulsatile ventricular assist device. The AB Portable Driver is a portable console for this system. We experienced two cases with accelerated hemolysis while receiving support by the AB Portable Driver. The purpose of this study was to clarify the mechanical differences associated with the hemolysis between the AB5000 console and the AB Portable Driver. The mock circulatory system modeled by an AB5000 ventricle and a blood sampling bag of vinyl chloride was run with an AB5000 console or AB Portable Driver. The peak drive-line pressure, the mean arterial cannula pressure and the pumping rate of the VAD were recorded. The AB5000 console generated a peak drive-line pressure of 280-300 mm Hg in LVAD mode and 210-220 mm Hg in RVAD mode, approximately 100 mm Hg lower than officially documented. In contrast, the AB Portable Driver generated pressures of 310-330 mm Hg in LVAD mode and 230-250 mm Hg in RVAD mode, 65-95 mm Hg higher than officially documented. The AB Portable Driver console generates higher drive-line pressures than the AB5000 console, possibly explaining the accelerated hemolysis.

The future of heart valve replacement: recent developments and translational challenges for heart valve tissue engineering

Heart valve replacement is often the only solution for patients suffering from valvular heart disease. However, currently available valve replacements require either life-long anticoagulation or are associated with valve degeneration and calcification. Moreover, they are suboptimal for young patients, because they do not adapt to the somatic growth. Tissue-engineering has been proposed as a promising approach to fulfil the urgent need for heart valve replacements with regenerative and growth capacity. This review will start with an overview on the currently available valve substitutes and the techniques for heart valve replacement. The main focus will be on the evolution of and different approaches for heart valve tissue engineering, namely the in vitro, in vivo and in situ approaches. More specifically, several heart valve tissue-engineering studies will be discussed with regard to their shortcomings or successes and their possible suitability for novel minimally invasive implantation techniques. As in situ heart valve tissue engineering based on cell-free functionalized starter materials is considered to be a promising approach for clinical translation, this review will also analyse the techniques used to tune the inflammatory response and cell recruitment upon implantation in order to stir a favourable outcome: controlling the blood-material interface, regulating the cytokine release, and influencing cell adhesion and differentiation. In the last section, the authors provide their opinion about the future developments and the challenges towards clinical translation and adaptation of heart valve tissue engineering for valve replacement. Copyright © 2016 John Wiley & Sons, Ltd.

Moving Beyond SHOCK: New Paradigms in the Management of Acute Myocardial Infarction Complicated by Cardiogenic Shock

The current management of patients with acute myocardial infarction complicated by cardiogenic shock (AMI-CS) is associated with a high rate of mortality, despite widespread regional implementation of rapid transfer to percutaneous coronary intervention-capable centres for prompt infarct-related artery reperfusion. The limited clinical effectiveness of early revascularization in patients with AMI-CS might be secondary to the extent of coronary artery disease in these patients and the risk of incomplete revascularization, as well as the lower probability of achieving successful reperfusion compared with acute myocardial infarction without hemodynamic instability. Also, the severity of end-organ injury is a critical determinant of outcome. We review adjunctive therapies to early revascularization in AMI-CS, specifically with a focus on the role of short-term mechanical circulatory support. In selected patients with AMI-CS, there might be a benefit associated with early institution of mechanical circulatory support before revascularization.

Bridge-to-decision therapy with a continuous-flow external ventricular assist device in refractory cardiogenic shock of various causes

BACKGROUND

Mortality for refractory cardiogenic shock remains high. In this patient cohort, there have been mixed results in mechanical circulatory support device use as a bridge-to-decision therapy. We evaluated a continuous-flow external ventricular assist device (VAD), CentriMag VAD (Thoratec Corp., Pleasanton, CA), in patients with various causes of refractory cardiogenic shock.

METHODS AND RESULTS

This is a retrospective review of adult patients who underwent surgical CentriMag VAD insertion as bridge-to-decision therapy. From January 2007 through June 2012, 143 patients received CentriMag VAD. The cause of refractory cardiogenic shock was failure of medical management in 71 patients, postcardiotomy shock in 37, graft failure post-heart transplantation in 22, and right ventricular failure post-implantable left VAD in 13. Mean age was 52±16 years, and 71% were in INTERMACS (Interagency Registry for Mechanically Assisted Circulatory Support) profile 1. Among 158 device runs, device configuration was BiVAD in 67%, isolated right VAD in 26%, and isolated left VAD in 8%. Median duration of support was 14 days (interquartile range, 8-26). Survival was 69% at 30 days and 49% at 1 year. The next destination after the CentriMag VAD was myocardial recovery in 30%, device exchange to an implantable VAD in 15%, and heart transplantation in 18%. The failure of medical management and the graft failure post-heart transplantation groups had higher 30-day survival compared with the postcardiotomy shock group. Major bleeding events occurred in 33% and cerebrovascular accidents in 14%. There was no CentriMag pump failure or thrombosis.

CONCLUSIONS

Bridge-to-decision therapy with CentriMag VAD is feasible in a variety of refractory cardiogenic shock settings. Patients with postcardiotomy shock have inferior survival.

Current status of extracorporeal ventricular assist devices in Japan

Extracorporeal VADs are less expensive, their prices reimbursable by the health insurance being about one-sixth of those of implantable VADs in Japan. However, a disadvantage is that, in Japan, their use is restricted to hospitals, necessitating prolonged hospitalization, reducing the patients' quality of life. According to the Japanese registry for Mechanically Assisted Circulatory Support, the survival rate does not differ significantly between patients with extracorporeal and implantable VADs. As in Europe and North America, extracorporeal VADs in Japan are commonly used as Bridge to Decision or Bridge to Recovery. Extracorporeal VADs are switched to implantable VADs as a Bridge-to-Bridge strategy after stabilization or when cardiac function recovery fails. They are also used as right ventricular assist devices (RVADs) in patients with right heart failure. A special characteristic of extracorporeal VADs in Japan is their frequent use as a Bridge to Candidacy. In Japan, indications for implantable VADs are restricted to patients registered for heart transplantation. Therefore, in patients who cannot be registered for transplantation because of transient renal dysfunction, etc., due to heart failure, extracorporeal VADs are used first, and then replaced by implantable VADs after transplant registry is done. Here, we describe the current status of extracorporeal VADs in Japan, focusing on the environmental backgrounds, along with a review of the relevant literature.

Mechanical circulatory support in cardiogenic shock

Despite advances in coronary revascularization and widespread use of primary percutaneous interventions, cardiogenic shock complicating an acute ST-elevation myocardial infarction (CSMI) remains a clinical challenge with high mortality rates. Conservative management with catecholamines is associated with serious limitations, including arrhythmias, increased myocardial oxygen consumption, and inadequate circulatory support. Clinicians have therefore turned to mechanical means of circulatory support. Circulatory assist systems for CSMI can be distinguished by the method of placement (i.e. percutaneous vs. surgical), the type of circulatory support (i.e. left ventricular, right ventricular, or biventricular pressure and/or volume unloading), and whether they are combined with extracorporal membrane oxygenation (ECMO). The percutaneous assist systems most commonly used in CSMI are the intra-aortic balloon pump (IABP), venoarterial ECMO, the Impella pump, and the TandemHeart. Decades of clinical studies and experience demonstrated haemodynamic improvement, including elevation of diastolic perfusion pressure and cardiac output. Recently, the large randomized IABP-Shock II Trial did not show a significant reduction in 30-day mortality in CSMI with IABP insertion. There are no randomized study data available for ECMO use in CSMI. Both the Impella pump and the TandemHeart did not reduce 30-day mortality when compared with IABP in small randomized controlled trials (RCTs). In conclusion, despite the need for effective mechanical circulatory support in CSMI, current devices, as tested, have not been demonstrated to improve short- or long-term survival rates. RCTs testing the optimal timing of device therapy and optimal device design are needed to improve outcomes in CSMI.

Mechanical circulatory support for cardiogenic shock

Cardiogenic shock (CS) is a syndrome of progressive depression of myocardial function with systemic hypoperfusion. It occurs due to various aetiologies such as acute myocardial infarction, myocarditis, acute decompensated heart failure and postcardiotomy. Cardiogenic shock carries poor prognosis, and medical therapy alone is not effective. Mechanical circulatory support is required to unload the ventricles, decrease the myocardial demand, prevent further injury, improve the coronary perfusion, stabilise the haemodynamics and maintain the end-organ perfusion before definitive interventions such as coronary reperfusion can take place. Currently, there are several methods of mechanical circulatory support. These include extracorporeal life support, paracorporeal or extracorporeal ventricular-assist devices, percutaneous ventricular assist devices, intra-aortic balloon counterpulsation and total artificial heart. In this review, we discuss the role of each of these circulatory support devices in the management of acute cardiac failure.

Mechanical assistance of the circulation during cardiogenic shock

PURPOSE OF REVIEW

Cardiogenic shock still has a grave prognosis. We present the recent advances in mechanical circulatory support (MCS) for the treatment of refractory cardiogenic shock.

RECENT FINDINGS

The contraindications for short-term MCS in rapid-onset cardiogenic shock are becoming fewer and the threshold for its application has been progressively lowered. Short-term MCS is increasingly used in refractory cardiac arrest and will be probably integrated as the last means in the advanced cardiopulmonary resuscitation algorithm (provided there is experienced team and technical support). Improved device technology has contributed to improved results of long-term MCS. Emergent application of long-term MCS in patients with critical cardiogenic shock after a long history of progressively deteriorating end-stage chronic heart failure should be interpreted as delayed application associated with increased mortality.

SUMMARY

Although MCS can be life saving in cardiogenic shock, the results are still suboptimal. Mortality is associated with the critical presupport state and the adverse events during MCS. Early initiation of support that meets the patient's requirements, potent support in the early phase, adverse event prevention, global combined management (surgical, interventional, medical), balanced support duration, bridging to further therapeutic modalities including heart transplantation or longer-term support, and advanced technology could offer improved results.

Cardiogenic Shock in Women

Cardiogenic shock (CS) describes the physiologic state in which reduced cardiac output and resultant tissue hypoxia occur in the presence of adequate intravascular volume. Among patients hospitalized with myocardial infarction (MI), CS is the foremost cause of death. Women are more susceptible to CS than men in the setting of ST segment increase MI. Introduction of early revascularization strategies and mechanical ventricular support have seen a decrease in short-term mortality from CS. However, the prognosis following CS remains poor. This article examines the prevalence, causes, pathophysiology, and therapeutic options for CS among women.

Preliminary in vivo testing of a novel pump for short-term extracorporeal life support

BACKGROUND

Blood pumps used for temporary circulatory support have limitations. We propose a novel device designed for short-term extracorporeal support that is intrinsically volume responsive, afterload insensitive, and incapable of cavitation or excessive hemolysis. After in vitro testing, we performed the initial in vivo implantations and assessments.

METHODS

The BioVAD prototype (MC3, Inc, Ann Arbor, MI) was implanted in 6 adult male sheep (60.2±2.8 kg) through the left ventricular apex and descending thoracic aorta. Arterial, left and right atrial, and pump inlet and outlet pressures and BioVAD flow were measured and recorded. The animals were volume loaded to assess volume responsiveness, and the inlet lines were abruptly clamped during maximum support to observe for cavitation. An acute heart failure model was created with rapid ventricular pacing, and the animals were supported for 4 hours.

RESULTS

Peak flow was 3.19±0.56 L/min and increased to 3.71±0.53 L/min with 20 mm Hg vacuum-assisted drainage. Without manual changes in pump settings, pump flow increased 17.5% with volume loading. During acute venous line occlusion, there was no evidence of cavitation, and inlet suction was minimal. Hemodynamics were maintained for 4 hours during acute heart failure.

CONCLUSIONS

The BioVAD provided adequate flow in an acute in vivo model. Its design may be superior for short-term extracorporeal support.

Post myocardial infarction cardiogenic shock: a review of current therapies

Cardiogenic shock is often a devastating consequence of acute myocardial infarction (MI) and portends to significant mortality and morbidity. Despite improvements in expediting the time to treatment and enhancements in available medical therapy and reperfusion techniques, cardiogenic shock remains the most common cause of mortality following MI. Post-MI cardiogenic shock most commonly occurs as a consequence of severe left ventricular dysfunction. Right ventricular (RV) MI must also be considered. Mechanical complications including acute mitral regurgitation, ventricular septal rupture, and ventricular free-wall rupture can also lead to cardiogenic shock. Rapid diagnosis of cardiogenic shock and its underlying cause is pivotal to delivering definitive therapy. Intravenous vasoactive agents and mechanical support devices may temporize the patient's hemodynamic status until definitive therapy by percutaneous or surgical intervention can be performed. Despite prompt management, post-MI cardiogenic shock mortality remains high.