The use of Impella 2.5 in severe refractory cardiogenic shock complicating an acute myocardial infarction

Impella - Current issues and future expectations for the percutaneous, microaxial flow left ventricular assist device

The importance of temporary mechanical circulatory support for treating acute heart failure with cardiogenic shock is increasingly recognized, and Impella (Abiomed, Danvers, MA, USA) has received particular attention in this regard. Impella is an axial flow left ventricular assist device (LVAD) built into the tip of a catheter. It is inserted via a peripheral artery and implanted into the left ventricle. Although the morphology of Impella is different from a typical LVAD, it has similar actions and effects as an LVAD in terms of left ventricular drainage and aortic blood delivery. Impella increases mean arterial pressure (MAP) and systemic blood flow, thereby improving peripheral organ perfusion and promoting recovery from multiple organ failure. In addition, left ventricular unloading with increased MAP increases coronary perfusion and decreases myocardial oxygen demand, thereby promoting myocardial recovery. Impella is also useful as a mechanical vent of the left ventricle in patients supported with veno-arterial extracorporeal membrane oxygenation. Indications for Impella include emergency use for cardiogenic shock and non-emergent use during high-risk percutaneous coronary intervention and ventricular tachycardia ablation. Its intended uses for cardiogenic shock include bridge to recovery, durable device, heart transplantation, and heart surgery. Prophylactic use of Impella in high-risk patients undergoing open heart surgery to prevent postcardiotomy cardiogenic shock is also gaining attention. While there have been many case reports and retrospective studies on the benefits of Impella, there is little evidence based on sufficiently large randomized controlled trials (RCTs). Currently, several RCTs are now ongoing, which are critical to determine when, for whom, and how these devices should be used. In this review, we summarize the principles, physiology, indications, and complications of the Impella support and discuss current issues and future expectations for the device.

Microaxial Left Ventricular Assist Device in Cardiogenic Shock: A Systematic Review and Meta-Analysis

Microaxial left ventricular assist devices (LVAD) are increasingly used to support patients with cardiogenic shock; however, outcome results are limited to single-center studies, registry data and select reviews. We conducted a systematic review and meta-analysis, searching three databases for relevant studies reporting on microaxial LVAD use in adults with cardiogenic shock. We conducted a random-effects meta-analysis (DerSimonian and Laird) based on short-term mortality (primary outcome), long-term mortality and device complications (secondary outcomes). We assessed the risk of bias and certainty of evidence using the Joanna Briggs Institute and the GRADE approaches, respectively. A total of 63 observational studies (3896 patients), 6 propensity-score matched (PSM) studies and 2 randomized controlled trials (RCTs) were included (384 patients). The pooled short-term mortality from observational studies was 46.5% (95%-CI: 42.7–50.3%); this was 48.9% (95%-CI: 43.8–54.1%) amongst PSM studies and RCTs. The pooled mortality at 90 days, 6 months and 1 year was 41.8%, 51.1% and 54.3%, respectively. Hemolysis and access-site bleeding were the most common complications, each with a pooled incidence of around 20%. The reported mortality rate of microaxial LVADs was not significantly lower than extracorporeal membrane oxygenation (ECMO) or intra-aortic balloon pumps (IABP). Current evidence does not suggest any mortality benefit when compared to ECMO or IABP.

Axial flow ventricular assist devices in cardiogenic shock complicating acute myocardial infarction

Cardiogenic shock (CS) remains the leading cause of death in patients hospitalised with acute myocardial infarction with mortality as high as 40%-50% prior to hospital discharge. The failure of inotropic therapy to maintain adequate perfusion and to prevent irreversible end-organ failure has led to attempts to improve outcomes by mechanical circulatory support (MCS) devices. Axial flow ventricular assist devices, namely Impella, are an attractive therapeutic option due to their positive haemodynamic benefits and ease of use. Despite clear beneficial haemodynamic effects, which should significantly impact on the pathophysiology of CS, there are currently no clear data to support their use in the reduction of clinical end points such as cardiac death. This review summarises and critically evaluates the current scientific evidence for the use of axial flow ventricular assist devices and highlights gaps in our understanding. Given such gaps, a consensus multidisciplinary approach, predicated on emphasising timely diagnosis and appropriate use of MCS, is vital to ensure that the right patient is paired with the right device at the right time.

Left Ventricle Architecture and Valvular Integrity Following Microaxial Mechanical Support: A Two-Year Follow-Up Study

Although the use of microaxilar mechanical circulatory support systems may improve the outcome of patients with cardiogenic shock (CS), little is known about its effect on the long-term structural integrity of left ventricular (LV) valves as well as on the development of LV-architecture. Therefore, we aimed to study the integrity of the LV valves and architecture and function after Impella support. Thus, 84 consecutive patients were monitored over two years having received Impella^TM CP (n = 24) or 2.5 (n = 60) for refractory CS (n = 62) or for high-risk percutaneous coronary interventions (n = 22) followed by optimal medical treatment. Beside a significant increase in LV ejection fraction after two years (p ≤ 0.03 vs. pre-implantation), we observed a statistically significant decrease in LV dilation (p < 0.001) and severity of mitral valve regurgitation (p = 0.007) in the two-year follow-up period, suggesting an improved LV architecture. Neither the duration of support, nor the size of the Impella device or the indication for its use revealed any devastating impact on aortic or mitral valve integrity. These findings indicate that Impella device is a safe means of support of LV-function without detrimental long-term effects on the structural integrity of LV valves regardless of the size of the device or the indication of support.

Contemporary device management of cardiogenic shock following acute myocardial infarction

Despite advances in the overall management of acute myocardial infarction (AMI), cardiogenic shock in the setting of AMI (CS-AMI) continues to be associated with poor patient outcomes. There are multiple devices that can be used in CS-AMI to support the failing circulation, although their utility in improving outcomes as compared with conventional pharmacotherapy of vasopressors and inotropes remains to be established. This contemporary review provides an update on the evidence base for each of these techniques. In CS-AMI, acute thrombotic occlusion of a major epicardial artery leads to hypoxia and myocardial ischaemia in the territory subtended by that vessel. The resultant regional dysfunction in myocardial contractility can severely compromise stroke volume and result in acute circulatory failure, systemic hypoperfusion, lactic acidosis, multi-organ failure and ultimately death.

Biventricular Unloading with Impella and Venoarterial Extracorporeal Membrane Oxygenation in Severe Refractory Cardiogenic Shock: Implications from the Combined Use of the Devices and Prognostic Risk Factors of Survival

Since mechanical circulatory support (MCS) devices have become integral component in the therapy of refractory cardiogenic shock (RCS), we identified 67 patients in biventricular support with Impella and venoarterial Extracorporeal Membrane Oxygenation (VA-ECMO) for RCS between February 2013 and December 2019 and evaluated the risk factors of mortality in this setting. Mean age was 61.07 ± 10.7 and 54 (80.6%) patients were male. Main cause of RCS was acute myocardial infarction (AMI) (74.6%), while 44 (65.7%) were resuscitated prior to admission. The mean Simplified Acute Physiology Score II (SAPS II) and Sequential Organ Failure Assessment Score (SOFA) score on admission was 73.54 ± 16.03 and 12.25 ± 2.71, respectively, corresponding to an expected mortality of higher than 80%. Vasopressor doses and lactate levels were significantly decreased within 72 h on biventricular support (p < 0.05 for both). Overall, 17 (25.4%) patients were discharged to cardiac rehabilitation and 5 patients (7.5%) were bridged successfully to ventricular assist device implantation, leading to a total of 32.8% survival on hospital discharge. The 6-month survival was 31.3%. Lactate > 6 mmol/L, vasoactive score > 100 and pH < 7.26 on initiation of biventricular support, as well as Charlson comorbity index > 3 and prior resuscitation were independent predictors of survival. In conclusion, biventricular support with Impella and VA-ECMO in patients with RCS is feasible and efficient leading to a better survival than predicted through traditional risk scores, mainly via significant hemodynamic improvement and reduction in lactate levels.

Percutaneous Biventricular Mechanical Heart Support in Cardiogenic Shock: A Nursing Case Report

INTRODUCTION

Only a few cases of biventricular cardiogenic shock have been treated with Impella circulatory assist devices in the United States.

CLINICAL FINDINGS

A 29-year-old man came to the emergency department because of cough, shortness of breath, fever, and chills. Initial assessment revealed hypotension; an elevated creatinine level of 2.1 mg/dL; and markedly elevated results on liver function tests, with alanine transaminase 5228 IU/L and aspartate aminotransferase 6200 IU/L. The patient's signs and symptoms met criteria for New York Heart Association class IV heart failure and associated poor prognosis for recovery.

DIAGNOSIS

Echocardiography revealed dilated cardiomyopathy and biventricular failure with an ejection fraction of 15%. Results of an endomyocardial biopsy confirmed the diagnosis of myocarditis.

INTERVENTIONS

After unsuccessful treatment with inotropes, biventricular support was started with an Impella CP device in the left ventricle and an Impella RP device in the pulmonary artery.

OUTCOMES

The patient was maintained on support for 8 days and was discharged to home from the hospital after 27 days. Repeat echocardiography 90 days after discharge indicated improvement in ejection fraction to 40%. At follow-up 16 weeks after discharge, all signs and symptoms of heart failure had resolved. The patient has not had any inpatient readmissions to the hospital to date.

CONCLUSION

This case presents an opportunity for analysis of care activities and role responsibilities of bedside nurses in caring for this patient. Discussion of this case expands the literature describing nursing activities associated with caring for patients with Impella devices.

Haemodynamic efficacy of microaxial left ventricular assist device in cardiogenic shock: a systematic review and meta-analysis

The Impella percutaneous mechanical circulatory support device is designed to augment cardiac output and reduce left ventricular wall stress and aims to improve survival in cases of cardiogenic shock. In this meta-analysis we investigated the haemodynamic effects of the Impella device in a clinical setting. We systematically searched all articles in PubMed/Medline and Embase up to July 2019. The primary outcomes were cardiac power (CP) and cardiac power index (CPI). Survival rates and other haemodynamic data were included as secondary outcomes. For the critical appraisal, we used a modified version of the U.S. Department of Health and Human Services quality assessment form. The systematic review included 12 studies with a total of 596 patients. In 258 patients the CP and/or CPI could be extracted. Our meta-analysis showed an increase of 0.39 W [95% confidence interval (CI): 0.24, 0.54], (p = 0.01) and 0.22 W/m² (95% CI: 0.18, 0.26), (p < 0.01) for the CP and CPI, respectively. The overall survival rate was 56% (95% CI: 0.50, 0.62), (p = 0.09). The quality of the studies was moderate, mostly due to the presence of confounders. Our study suggests that in patients with cardiogenic shock, Impella support seems effective in augmenting CP(I). This study merely investigates the haemodynamic effectiveness of the Impella device and does not reflect the complete clinical impact for the patient.

Impact of microaxillar mechanical left ventricular support on renal resistive index in patients with cardiogenic shock after myocardial infarction: a pilot trial to predict renal organ dysfunction in cardiogenic shock

OBJECTIVES

To evaluate the effects of left ventricular support with the microaxial left ventricular pump using the Impella device on the renal resistive index assessed by Doppler ultrasonography in haemodynamically stable patients with cardiogenic shock following myocardial infarction.

METHODS

A non-randomised interventional single-centre study. Consecutive patients with cardiogenic shock supported with an Impella were included during May 2018 and October 2018. The renal resistive index determined as a quotient of (peak systolic velocity - end diastolic velocity)/ peak systolic velocity was obtained using Doppler ultrasound; invasive blood pressure was determined in radial artery simultaneously for safety reasons.

RESULTS

A total of 15 patients were measured. The renal resistive index was determined in both kidneys in 13 patients and for one kidney in two patients, respectively. The mean difference between right and left renal resistive index was 0.026 ± 0.023 (P=0.72). When increasing the Impella microaxillar mechanical support by a mean of 0.44 L/min (±0.2 L/min), the renal resistive index decreased significantly from 0.66 ± 0.08 to 0.62 ± 0.06 (P<0.001) consistently in all patients, whereas systolic or diastolic blood pressure remained unchanged.

CONCLUSIONS

Microaxillar mechanical support by the Impella device in haemodynamically stable patients with cardiogenic shock led to a significant reduction of the renal resistive index without affecting systolic or diastolic blood pressure. This observation is consistent with the notion that Impella support may promote renal organ protection by enhancing renal perfusion.

Management of advanced heart failure: a review

INTRODUCTION

Heart failure (HF) has become a global pandemic. Despite recent developments in both medical and device treatments, HF incidences continues to increase. The current definition of HF restricts itself to stages at which clinical symptoms are apparent. In advanced heart failure (AdHF), it is universally accepted that all patients are refractory to traditional therapies. As the number of HF patients increase, so does the need for additional treatments, with an increased proportion of patients requiring advanced therapies. Areas covered: This review discusses extensive evidence for the effect of medical treatment on HF, although the data on the effect on AdHF is scare. Authors review the relevant literature for treating AdHF patients. Furthermore, mechanical circulatory devices (MCD) have emerged as an alternative to heart transplantation and have been shown to enhance quality of life and reduce mortality therefore authors also review the current literature on the different MCD and technologies. Expert commentary: More patients will need advanced therapies, as the access to heart transplantation is limited by the number of available donors. AdHF patients should be identified timely since the window of opportunities for advanced therapy is narrow as their morbidity is progressive and survival is often short.

Place de l’assistance circulatoire dans le choc cardiogénique en France en 2018 : revue de la littérature et perspectives

Le choc cardiogénique reste de nos jours une entité mal définie, assez fréquente en pratique clinique (60 000–70 000 cas/an en Europe), dont le pronostic est sombre, avec une mortalité souvent supérieure à 40 % à 30 jours. À travers cette revue de la littérature, nous essaierons de définir cette entité et ses étiologies, avant de parler de son incidence et de son pronostic. L’approche physiopathologique du choc cardiogénique nous permettra par la suite d’approcher sa prise en charge thérapeutique classique (gestion de la volémie, amines inotropes et vasoconstrictives, ventilation) et les limites de cette dernière. Ainsi, nous aborderons les assistances circulatoires et cardiocirculatoires disponibles en France, afin de les envisager au sein d’une stratégie globale de prise en charge du patient en choc cardiogénique. Nous discuterons plus spécifiquement leurs indications ainsi que l’importance du moment d’implantation afin d’optimiser leur efficacité. Enfin, nous évoquerons les assistances actuellement en développement, mais également les nouvelles stratégies thérapeutiques qui pourraient arriver dans les prochaines années.

When more is not better-appropriately excluding patients from mechanical circulatory support therapy

Mechanical circulatory support (MCS) devices are continually evolving and are providing greater hemodynamic support. This review was conducted to evaluate the prophylactic use of MCS in hemodynamically stable patients who were awaiting future coronary artery revascularization. A thorough review of published literature was conducted to evaluate for patients and clinical scenarios that are indicated for MCS, including hemodynamically stable and unstable patients awaiting revascularization. Although there have been several studies demonstrating the benefit of MCS use in hemodynamically unstable patients, there was limited trials in patients that were hemodynamically stable. The use of prophylactic MCS was limited to intra-aortic balloon pump (IABP) in "high risk" patients awaiting coronary artery bypass grafting (CABG). This review article was conducted to evaluate for possible prophylactic MCS in patients awaiting revascularization. In hemodynamically stable patients, literature is limited to the use of IABP for "high-risk" patients awaiting CABG. A thorough review of literature suggest that hemodynamically stable patients likely would not benefit from prophylactic placement MCS while awaiting revascularization although further clinical trials are needed to identify the ideal patients and clinical scenarios for the use of MCS.

The effectiveness and safety of the Impella ventricular assist device for high-risk percutaneous coronary interventions: A systematic review

BACKGROUND

Small randomized controlled trials (RCTs) and observational studies have examined the effectiveness and safety of the Impella device, a percutaneous left ventricular assist device, in the setting of high-risk percutaneous coronary intervention (PCI). However, data are sparse and results are conflicting. Our objective was to evaluate the effectiveness and safety of the Impella device in high-risk patients undergoing PCI via a systematic review of the literature.

METHODS

We searched Medline, EMBASE, and the Cochrane Library for RCTs and observational studies that evaluated the Impella device in high-risk patients undergoing PCI. Inclusion was restricted to studies in which ≥10 patients received the Impella device; both uncontrolled and controlled (versus intra-aortic-balloon pump [IABP]) studies were included.

RESULTS

A total of 20 studies (4 RCTs, 2 controlled observational studies, and 14 uncontrolled observational studies; 1,287 patients) were included, with follow-up ranging from 1 to 42 months. The use of Impella resulted in improved procedural and hemodynamic characteristics in controlled and uncontrolled studies. In controlled studies, the 30-day rates of all-cause mortality and MACE were similar across groups. In most uncontrolled studies, the 30-day rates of all-cause mortality were generally low (range: 3.7%-10%), though rates of MACE were slightly higher (range: 5%-20%).

CONCLUSION

The Impella device was found to improve procedural and hemodynamic parameters, but only limited randomized data are available regarding clinical outcomes associated with its use. Large, multicenter RCTs are needed to definitively establish the effectiveness of the Impella device among high-risk PCI patients.

Long-term clinical results of acute myocardial infarction at the left main trunk requiring percutaneous cardiopulmonary support

The clinical results of patients with acute myocardial infarction (AMI) at the left main trunk (LMT) remain unclear, especially in cases requiring percutaneous cardiopulmonary support (PCPS). Twenty seven cases of AMI at the LMT requiring emergent PCPS were retrospectively investigated. These 27 patients were aged 44-83 years (65.6 ± 8.6 years) and 20 (81.5%) were men. Peak creatine kinase (CK) leakage ranged from 538 to 34,010 IU/l (13,553 ± 7656 IU/l). Eight (29.6%) patients were discharged without mechanical support. Ten (37.0%) patients underwent left ventricular assist device (LVAD) implantation, five of whom with preoperative organ failure could not survive more than 6 months after implantation. The other nine (33.3%) patients died of low output syndrome or brain damage. The overall survival rates were 53.7, 41.3, 33.0, and 28.3% at 3 months, 6 months, 1 year, and 2 years, respectively. Multivariate analysis showed that Killip class 3/4 at hospital arrival was an independent risk factor for hospital mortality (odds ratio 20.4). Patients with more than 5 days of PCPS support period (n = 6), ≥ 4 h to revascularization (n = 6) or maximum CK leakage ≥20,000 IU/dl (n = 3) were not associated with successful PCPS or IABP weaning. The long-term clinical outcomes of patients with LMT disease requiring PCPS is devastating. Rapid cardiopulmonary resuscitation and coronary revascularization and timely insertion of LVAD before the onset of complications might lead to better survival.

Management and outcome of patients supported with Impella 5.0 for refractory cardiogenic shock

Introduction

Cardiogenic shock refractory to standard therapy with inotropes and/or intra-aortic balloon pump is accompanied with an unacceptable high mortality. Percutaneous left ventricular assist devices may provide a survival benefit for these very sick patients. In this study, we describe our experience with the Impella 5.0 device used in the setting of refractory cardiogenic shock.

Methods

In this observational, retrospective, single-center study we included all the consecutive patients supported with Impella 5.0, between May 2008 and December 2013, for refractory cardiogenic shock. Patients’ baseline and procedural characteristics, hemodynamics and outcome to the first 48 h of support, to ICU discharge and day-28 visit were collected.

Results

A total of 40 patients were included in the study. Median age was 57 years and 87.5 % were male. Cardiogenic shock resulted from acute myocardial infarction in 17 patients (43 %), dilated cardiomyopathy in 12 (30 %) and postcardiotomy cardiac failure in 7 (18 %). In 15 patients Impella 5.0 was added to an ECMO to unload the left ventricle. The median SOFA score for the entire cohort prior to circulatory support was 12 [10–14] and the duration of Impella support was 7 [5–10] days. We observed a significant decrease of the inotrope score (10 [1–17] vs. 1 [0–9]; p = 0.04) and the lactate values (3.8 [1.7–5.9] mmol/L vs. 2.5 [1.5–3.4] mmol/L; p = 0.01) after 6 h of support with Impella 5.0. Furthermore, at Impella removal the patients’ left ventricular ejection fraction improved significantly (p < 0.001) when compared to baseline. Cardiac recovery, bridge to left ventricular assist device or heart transplantation was possible in 28 patients (70 %). Twenty-six patients (65 %) survived at day 28. A multivariate analysis showed a higher risk of mortality for patients with acute myocardial infarction (hazard ratio = 4.1 (1.2–14.2); p = 0.02).

Conclusions

Impella 5.0 allowed fast weaning of inotropes and might facilitate myocardial recovery. Despite high severity scores at admission, day-28 mortality rate was better than predicated.