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# Each Author contributed equally to the writing of the publication.
Alexander M. Bernhardt
Correspondence
Reprint requests: Alexander M. Bernhardt, MD, University Heart and Vascular Center Hamburg, Department of Cardiovascular Surgery, Martinistrasse 52, 20246 Hamburg, Germany. Tel: 0049-40-74105-3440; Fax: 0049-40-74105-4931;
Chairs: Alexander M. Bernhardt, MD; Jason Gluck, DO. Co-Chairs: Arthur Reshad Garan, MD, MS; Shelley Hall, MD; Awori Hayanga, MD; Ivan Knezevic, MD; Federico Pappalardo; MD; Joyce Wald, DO. Contributing Writers: Cristiano Amarelli, MD; William L. Baker, PharmD; David Baran, MD; Daniel Dilling, MD; Airlie Hogan, RN; Anna L. Meyer, MD; Ivan Netuka, MD; Minoru Ono, MD; Federico Pappalardo, MD; Gustavo Parrilla, MD; Duc Thin Pham, MD; Scott Silvestry, MD; Christy Smith, MD; Koji Takeda, MD; Sunu S. Thomas, MD, MSc; Esther Vorovich, MD, MSCE
Task Force 2:
Chair: Michael M. Givertz, MD. Co-Chair: Jo Ellen Rodgers, PharmD. Contributing Writers: Nana Aburjania, MD; Jean M. Connors, MD; Jasmin S. Hanke, MD; Elrina Joubert-Huebner, MD; Gal Levy, MD; Ann E. Woolley, MD, MPH
Task Force 3:
Chair: Hannah Copeland, MD. Co-Chairs: David L.S. Morales, MD; Amanda Vest, MBBS, MPH. Contributing Writers: Francisco A. Arabia, MD, MBA; Michael Carrier, MD, MBA; Christopher T. Salerno, MD; Benedikt Schrage, MD
Task Force 4:
Chair: Anita Deswal, MD, MPH. Co-Chair: Savitri Fedson, MD, MA. Contributing Writers: Larry A. Allen, MD, MHS; Cynthia J. Bither, CRNP; Shannon Dunlay, MD, MS; Paola Morejon, MD; Kay Kendall, MSW, LISW
Reviewers:
Michael Kiernan, MD; Sean Pinney, MD; Stephan Schueler, MD; Peter Macdonald, MD; Diyar Saeed, MD; Evgenij Potapov, MD; Tien M.H. Ng, PharmD
All five chairs contributed equally.
Despite medical advances, cardiogenic and pulmonary shock are associated with high mortality and morbidity.
The availability and use of acute or temporary mechanical support devices has grown over the years, with the goal of improving patient outcomes by temporarily providing support to allow time for organ recovery or for longer term decisions including transition to durable therapies.
A collaborative effort commissioned by the International Society of Heart and Lung Transplantation and the Heart Failure Society of America has developed this critically needed guideline for the management of patients requiring acute mechanical circulatory support (MCS). This document covers definitions of cardiogenic and pulmonary shock, medical treatment and surgical interventions, management of patients supported with temporary devices, complications, special populations, and social and ethical dilemmas. The writing groups include multidisciplinary members from both societies with a focus on diversity in gender, geography, area of expertise and level of seniority. The target audience includes cardiologists, especially interventional and advanced heart failure specialists, pulmonary and critical care specialists, intensivists, and cardiothoracic surgeons, as well as referring providers.
After a review and evaluation of available literature and incorporation of the collective experience of the group, specific recommendations were assigned a class of recommendation and level of evidence. The definitions of the class of recommendation and level of evidence are listed in the Table and they are simplified into fewer categories given the paucity of high quality of evidence from randomized clinical trials of acute MCS.
TableDefinitions of Class of Recommendation and Level of Evidence
Further evolution of the ACC/AHA clinical practice guideline recommendation classification system: a report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines.
Task Force 1: Timing, Patient and Device Selection of Acute MCS, and Periprocedural and Postprocedural Care for Cardiogenic and Pulmonary Shock
This section provides contemporary definitions and outlines pathophysiology and epidemiology of cardiogenic and pulmonary shock. The severity and classification of shock is further defined along with underlying causes and hemodynamic profiles. The timing and requirements for acute MCS are detailed, including the role of shock teams, intensivists, nursing, and supportive care. Finally, specific indications, contraindications, techniques, and risks of available devices for left ventricular (LV), right ventricular (RV) and biventricular (BiV) support are reviewed.
Task Force 2: Adjunctive Pharmacological Management
This section focuses on the management of bleeding, thrombosis, and infection. Risk factors for hemocompatibility-related adverse events are reviewed and the importance of periprocedural planning is highlighted, including formulation of anticoagulation targets and discontinuation of background therapy. Device-specific recommendations regarding periprocedural and postprocedural antithrombotic therapy are provided along with pharmacokinetic information. The management of early and late bleeding, thromboembolism, and heparin-induced thrombocytopenia (HIT) are discussed. Definitions, types, and rates of infection during acute MCS support are outlined, and prophylactic, empiric, and targeted treatment approaches recommended.
Task Force 3: Specific Patient Populations
The population of patients presenting with CS is heterogenous. A range of patient characteristics, comorbidities, and specific shock etiologies may alter the risks and benefits of acute MCS. This section provides guidance in the management of women, racial and ethnic minorities, patients with adult congenital heart disease (ACHD), the elderly or frail, and those with obesity or cachexia who require acute MCS. In addition, specific recommendations are provided for patients with acute fulminant and those with post cardiotomy or post–cardiopulmonary resuscitation (CPR)-related shock. Owing to marked differences in body size, clinical presentation, and available devices, pediatric patients are not covered in this guideline.
Task Force 4: Goals of Care and Role of Palliative Care, Social Work, and Ethics
Decision-making for acute MCS is typically rapid and complex, and involves a variety of invasive options, a high degree of uncertainty in outcomes, and the potential for significant patient and family suffering. This section highlights the importance of shared decision-making and informed consent while engaging necessary stakeholders. Tools to frame conversations, including use of decision aids, are discussed. The important roles of palliative care specialists, social work, ethics consultation, and local religious leaders are detailed. Finally, the concept of medical futility is defined and a decommission check-list is provided.
Task Force 1: Timing, Patient and Device Selection of Acute MCS, and Periprocedural and Postprocedural Care for Cardiogenic and Pulmonary Shock
Cardiogenic Shock Definition
Cardiogenic shock (CS) results from a multitude of cardiovascular (CV) disorders and remains a highly fatal (30%–60%) and morbid syndrome despite different therapeutic approaches. CS is defined as a state of tissue hypoperfusion and end organ dysfunction owing to a primary cardiac disorder with low cardiac output (CO) that can present in different stages (Society for Cardiovascular Angiography and Interventions [SCAI]/Interagency Registry for Mechanically Assisted Circulatory Support [INTERMACS]).
SCAI clinical expert consensus statement on the classification of cardiogenic shock: This document was endorsed by the American College of Cardiology (ACC), the American Heart Association (AHA), the Society of Critical Care Medicine (SCCM), and the Society of Thoracic Surgeons (STS) in April 2019.
A primary cardiac insult (eg, acute myocardial infarction [AMI], acute-on-chronic heart failure (HF), fulminant myocarditis, massive pulmonary embolism) triggers CS. This initial insult results in an abrupt onset of acute or acute-on-chronic ventricular dysfunction (either systolic or diastolic) and stimulates a cascade of pathologic and compensatory reactions including systemic vasoconstriction, systemic inflammatory response syndrome, fluid retention, and impaired tissue microcirculation among others.
These mechanisms in turn result in progressive tissue hypoperfusion, coronary/myocardial hypoperfusion, and increased afterload with resultant further decrement in CO, thus propagating the death spiral of CS.
Temporal trends in incidence and patient characteristics in cardiogenic shock following acute myocardial infarction from 2010 to 2017: a Danish cohort study.
In the United States, analyses using the Nationwide Inpatient Sample (NIS) and the CATH-PCI registry, show a rising incidence of CS complicating STEMI from 6.5% in 2003 to 10.1% in 2010.
Temporal trends and outcomes of patients undergoing percutaneous coronary interventions for cardiogenic shock in the setting of acute myocardial infarction: a report from the CathPCI Registry.
Temporal trends in incidence and patient characteristics in cardiogenic shock following acute myocardial infarction from 2010 to 2017: a Danish cohort study.
Data surrounding CS incidence for non–AMI-related etiologies are more limited. Recent data from the NIS demonstrate a rising rate of non–AMI-related CS of 8.7 of 1000 hospitalizations compared with the previous era, with high mortality and 30-day readmission rates.
Racial, gender, and age disparities exist regarding risk of developing CS. Women, Asian/Pacific Islanders, and patients over the age of 75 demonstrate a higher incidence of AMI CS.
Furthermore, significant regional and hospital heterogeneity in CS management persists. Paralleling data seen with other conditions, higher volume centers are associated with improved outcomes, and as a result regionalization of CS care using a hub-and-spoke model has been proposed.
Shock Classifications by Severity: INTERMACS and SCAI Classifications
The INTERMACS profiles were developed to classify clinical severity of patients with advanced HF undergoing durable ventricular assist device (VAD) implantation.
Patients with acute CS by definition belong to INTERMACS 1 (“the crashing and burning” patient profile), potentially too sick for durable VAD therapy, with more chronic shock states being INTERMACS 2 to 4.
To provide further granularity, the SCAI classification system was created and jointly supported by the American College of Cardiology, the American Heart Association, the Society of Critical Care Medicine, and the Society of Thoracic Surgeons in 2019.
SCAI clinical expert consensus statement on the classification of cardiogenic shock: This document was endorsed by the American College of Cardiology (ACC), the American Heart Association (AHA), the Society of Critical Care Medicine (SCCM), and the Society of Thoracic Surgeons (STS) in April 2019.
The SCAI classification is an easily performed, bedside assessment that stratifies patients with CS into 5 categories: stage A, the at-risk patient; stage B, the patient with beginning CS; stage C, the patient with classic CS; stage D, the deteriorating/doom patient; and stage E, the extremis patient.
SCAI clinical expert consensus statement on the classification of cardiogenic shock: This document was endorsed by the American College of Cardiology (ACC), the American Heart Association (AHA), the Society of Critical Care Medicine (SCCM), and the Society of Thoracic Surgeons (STS) in April 2019.
By design, the SCAI classification has several advantages over the INTERMACS system: the SCAI classification system accounts for changes in clinical trajectory, allows for more granularity in patient description, is specifically designed for this patient population, and can be used to optimize patient selection for future CS trial enrollment. This classification may further elucidate appropriate timing of acute MCS.
The hemodynamic profile of patients in CS can also be classified along similar metrics as patients presenting with acute decompensated HF (ADHF), namely, that of (1) volume status: wet vs dry and (2) systemic perfusion: warm vs cold. Patients with CS typically present as cold and wet, characterized by decreased CO with elevated filling pressures and systemic vascular resistance.
Cold and dry patients or euvolemic CS may be due to either true CS or due to volume depletion. The warm and wet CS subset refers to patients with mixed shock either owing to the well-established inflammatory response seen after an AMI or owing to concomitant infection and sepsis.
Post hoc analyses from the Should We Emergently Revascularize Occluded Coronaries for Cardiogenic Shock (SHOCK) trial found that among patients with AMI-related cardiogenic shock (AMI-CS) with predominant LV shock, 64% of patients were cold and wet, 28% cold and dry, and 5% were warm and wet.
The clinical profile of patients with suspected cardiogenic shock due to predominant left ventricular failure: a report from the SHOCK Trial Registry. SHould we emergently revascularize Occluded Coronaries in cardiogenic shocK?.
Analysis of blood pressure data from the same trial also revealed that despite inclusion criteria of hypotension, 5% of enrolled patients had normotensive shock, defined as a systolic blood pressure of greater than 90 mm Hg despite evidence of end-organ hypoperfusion, with hemodynamic data demonstrating higher systemic vascular resistance than the remainder of the trial cohort.
The clinical profile of patients with suspected cardiogenic shock due to predominant left ventricular failure: a report from the SHOCK Trial Registry. SHould we emergently revascularize Occluded Coronaries in cardiogenic shocK?.
Interestingly, normotensive patients with CS demonstrated elevated in-hospital mortality rates compared with hypotensive patients (66% vs 43%; P = .001).
The clinical profile of patients with suspected cardiogenic shock due to predominant left ventricular failure: a report from the SHOCK Trial Registry. SHould we emergently revascularize Occluded Coronaries in cardiogenic shocK?.
The comparison of clinical outcomes between inferior ST-elevation myocardial infarction with right ventricular infarction vs without right ventricular infarction.
Right ventricular dysfunction in acute myocardial infarction complicated by cardiogenic shock: a hemodynamic analysis of the Should We Emergently Revascularize Occluded Coronaries for Cardiogenic Shock (SHOCK) trial and registry.
Compared with patients with LV-predominant CS, patients with RV-predominant CS demonstrate a shorter time to diagnosis of shock, less prevalence of multivessel disease or prior MI, and a higher incidence of inferior or posterior MI.
RV involvement in non AMI-CS can often be seen with a variety of etiologies, most commonly with acute-on-chronic LV failure. RV-predominant shock is also seen in decompensated pulmonary hypertension, pulmonary embolism, right sided valvular disorders, RV predominant cardiomyopathies, and right HF after heart transplantation or after left ventricular assist device (LVAD) implantation.
Table 1.1Hemodynamic and Echocardiographic Data that may be Supportive of RV Failure
Improved outcome of cardiogenic shock at the acute stage of myocardial infarction: a report from the USIK 1995, USIC 2000, and FAST-MI French nationwide registries.
Thirty-year trends (1975 to 2005) in the magnitude of, management of, and hospital death rates associated with cardiogenic shock in patients with acute myocardial infarction: a population-based perspective.
2014 AHA/ACC guideline for the management of patients with non-ST-elevation acute coronary syndromes: executive summary: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines.
Early revascularization in acute myocardial infarction complicated by cardiogenic shock. SHOCK Investigators. Should We Emergently Revascularize Occluded Coronaries for Cardiogenic Shock.
2013 ACCF/AHA guideline for the management of ST-elevation myocardial infarction: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines.
Ejection fraction, moderate or greater mitral regurgitation, presence of CS on admission or CS developing early rather than later in the course, successful percutaneous coronary intervention (PCI), and the culprit vessel are independent predictors of survival in AMI-CS.
Correlates of one-year survival inpatients with cardiogenic shock complicating acute myocardial infarction: angiographic findings from the SHOCK trial.
Implications of the timing of onset of cardiogenic shock after acute myocardial infarction: a report from the SHOCK Trial Registry. SHould we emergently revascularize Occluded Coronaries for cardiogenic shocK?.
CS owing to non-AMI causes span a range of etiologies and constitutes about 20% of CS cases. The majority (58% of non AMI-CS and 11% of total CS population) present with acute decompensation of chronic HF, 32% with valvular or mechanical causes (6% of total CS), 10% with stress cardiomyopathy (2% of total CS), and 10% with myocarditis (2% of total CS).
Compared with AMI-CS, non-AMI patients with CS are younger, more likely to be women, with larger ventricles, a higher degree of mitral regurgitation, and higher N-terminal pro-B-type natriuretic peptide levels.
Takotsubo or stress cardiomyopathy, typically considered benign, carries a 9.5% incidence of CS with in-hospital mortality ranging from 15% to 23.5% as compared with 2.3% (P < .001) in patients with stress cardiomyopathy who do not develop CS.
The pathophysiology is characterized by a multifactorial etiology in which vasodilatation and hemorrhage owing to cardiopulmonary bypass impact the final outcome. The spectrum of clinical settings varies from the situation in which the heart does not recover sufficient myocardial function to be weaned from cardiopulmonary bypass to abrupt cardiac arrest in the intensive care unit (ICU) during the postoperative period.
Obstructive Shock
The treatment of specific causes of cardiogenic or obstructive shock such as acute pulmonary embolism and cardiac tamponade require timely diagnosis and directed management such as drainage, anticoagulation, systemic or directed thrombolytics, manual thrombectomy, or surgery. Pharmacological support with vasopressors and/or acute MCS with temporary devices may be needed for patient stabilization.
Indications for Acute MCS
The indications for acute MCS in patients in CS vary owing to the heterogeneity in both etiology and severity of presentation. In addition to the baseline characteristics of patients with CS, the indication may also vary by the expected end points of the support (recovery, bridge to decision, mid- to long-term support). It is important to consider exit strategies from acute MCS to minimize medically futile cases. A multidisciplinary team-based approach is warranted to ensure the appropriate referral and timely treatment that are keys to survival benefit. An overview of selected acute MCS devices is displayed in Fig. 1.1.
Fig. 1.1Overview of devices for acute mechanical circulatory support. ECLS, extracorporeal life support; ECMO, extracorporeal membrane oxygenation; IABP, intra-aortic balloon pump.
Recently, data from the Detroit Cardiogenic Shock initiative showed for the first time a higher survival to discharge of 72%. Indeed, such results were achieved through an aggressive use of right heart catheterization, performed in 92% and acute MCS implanted in 74% of patients before PCI.
This study is one of the first demonstrating improved outcomes from CS through an organizational effort for early referral to a shock center, escalation of monitoring and eventually implantation of acute MCS. The study suggests that implementation of a coordinated shock team can improve outcomes through a multidisciplinary effort (Table 1.2).
Table 1.2Recommendations for Parameters for Identification of CS and Need for Acute MCS
Recommendation
Class of Recommendation
Level of Evidence
Classification of degree of shock, and laboratory tests including complete blood count, electrolytes, renal function, liver function, coagulation profile, arterial blood gas and lactate, and serial cardiac troponin levels should be routinely assessed.
I
C
Multidisciplinary evaluation by a shock team with use of an algorithmic approach is recommended.
I
B
Goals of care should be clearly defined when considering acute MCS.
I
C
Admission to an intensive care unit is recommended as soon as possible.
I
C
Aortic regurgitation should be systematically evaluated before MCS implantation.
I
C
Developing systems of care integrating MCS-capable hospitals (hubs) and spoke centers with defined protocols for early recognition, treatment, and transfer has the potential to improve outcomes of patients with CS.
II
C
Acute MCS hospitals should be available to provide support at all times.
Parameters of Evaluation to Select Device and Timing
When hypoperfusion persists despite preload and afterload optimization, the need for more CO should be considered. A higher inotropic dose and multiple inotropes have been demonstrated as significant risk factors and should drive referral to centers or an ICU, where acute MCS is feasible. The etiology of CS has a paramount role in the decision of the need for support and its timing. A reversible cause of CS (ie, successful reperfusion of ischemic lesions, myocarditis, postcardiotomy failure and post-transplant graft failure) should be a factor favoring timely implantation of a short-term device.
Timing of Acute MCS
Given the numerous etiologies of CS, diverse patient presentations, and differences in individual treatment practices, the optimal timing for acute MCS remains ill-defined. Historically and currently, inotropes and vasopressors are first-line therapies for hemodynamic instability and CS. These agents lack data showing benefit and have potential harm with coronary and peripheral vasoconstriction. Early initiation of acute MCS can mitigate the consequences of systemic hypoperfusion, worsening ischemia, and declining cardiac function by relieving ischemic burden, augmenting CO and minimizing medications with high cardiac oxygen demands.
Mechanical circulatory support in patients with cardiogenic shock in intensive care units: a position paper of the “Unité de Soins Intensifs de Cardiologie” group of the French Society of Cardiology, endorsed by the "Groupe Athérome et Cardiologie Interventionnelle" of the French Society of Cardiology.
2015 SCAI/ACC/HFSA/STS clinical expert consensus statement on the use of percutaneous mechanical circulatory support devices in cardiovascular care: endorsed by the American Heart Assocation, the Cardiological Society of India, and Sociedad Latino Americana de Cardiologia Intervencion; Affirmation of Value by the Canadian Association of Interventional Cardiology-Association Canadienne de Cardiologie d'intervention.
In patients with refractory CS with uncertain neurological prognosis (eg, after cardiorespiratory arrest), acute MCS can be used before durable therapies to allow for declaration of long-term candidacy.
2015 SCAI/ACC/HFSA/STS clinical expert consensus statement on the use of percutaneous mechanical circulatory support devices in cardiovascular care: endorsed by the American Heart Assocation, the Cardiological Society of India, and Sociedad Latino Americana de Cardiologia Intervencion; Affirmation of Value by the Canadian Association of Interventional Cardiology-Association Canadienne de Cardiologie d'intervention.
Temporary rather than durable MCS as a first-line device should be considered when immediate stabilization is needed to enable recovery of the heart and other organ systems, when surgical risk is prohibitive but may be attenuated by such stabilization, when support is required to facilitate a definitive procedure or intervention (such as revascularization or arrhythmia ablation), or when time is required to allow transplantation or durable MCS evaluation.
Short-term mechanical circulatory support as a bridge to durable left ventricular assist device implantation in refractory cardiogenic shock: a systematic review and meta-analysis.
Extracorporeal membrane oxygenation (ECMO)–CPR (eCPR) is increasingly being considered based on observational data. eCPR involves the placement of VA-ECMO emergently during chest compression to restore circulation when the heart is in cardiac arrest. Although overall post-eCPR survival to hospital discharge has been approximately 30%, at present there is insufficient evidence to recommend a widespread adoption of this approach.
Importantly, eCPR might be feasible in tertiary care centers with an established VA-ECMO program with rapid deployment teams, usually restricted to patients with a witnessed cardiac arrest, short no-flow time, a primary rhythm that may be cardioverted, and/or a reversible etiology (Table 1.3).
Table 1.3Recommendations for Timing of Acute MCS in CS
Recommendation
Class of Recommendation
Level of Evidence
Acute MCS should be initiated as soon as possible in patients with CS who fail to stabilize or continue to deteriorate despite initial interventions.
I
B
The use of acute MCS should be considered in patients with multiorgan failure to allow successful optimization of clinical status and neurologic assessment before placement of durable MCS or organ transplantation.
II
C
In patients with cardiac arrest receiving cardiopulmonary resuscitation, VA-ECMO can be considered.
II
C
When considering VA-ECMO, the need for left ventricular venting/unloading (pharmacologic or mechanical) should be considered.
II
B
MCS, mechanical circulatory support; VA ECMO, venoarterial extracorporeal membrane oxygenation.
Recommendations for Timing in Acute Coronary Syndromes
Despite prompt revascularization, patients with anterior STEMI and a significant amount of myocardium at risk suffer from high mortality and HF at mid-term follow-up. There is no survival benefit from routine intra-aortic balloon pump (IABP) regarding mortality, reinfarction, HF or infarct size reduction.
Intra-aortic balloon counterpulsation and infarct size in patients with acute anterior myocardial infarction without shock: the CRISP AMI randomized trial.
Although standard therapy for STEMI is rapid myocardial reperfusion, up to one-third of STEMI patients do not experience effective reperfusion as assessed by resolution of ST segment elevation. Moreover, reperfusion itself may cause myocardial damage (reperfusion injury) and life-threatening ventricular arrhythmias. Large registries have reported a potential benefit of acute MCS in CS, particularly if implanted before revascularization.
Mechanical circulatory support in patients with cardiogenic shock in intensive care units: a position paper of the “Unité de Soins Intensifs de Cardiologie” group of the French Society of Cardiology, endorsed by the "Groupe Athérome et Cardiologie Interventionnelle" of the French Society of Cardiology.
Feasibility of early mechanical circulatory support in acute myocardial infarction complicated by cardiogenic shock: The Detroit cardiogenic shock initiative.
Percutaneous left ventricular assist devices vs. intra-aortic balloon pump counterpulsation for treatment of cardiogenic shock: a meta-analysis of controlled trials.
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.
Use of the Impella device for acute coronary syndrome complicated by cardiogenic shock - experience from a single heart center with analysis of long-term mortality.
A randomized clinical trial to evaluate the safety and efficacy of a percutaneous left ventricular assist device versus intra-aortic balloon pumping for treatment of cardiogenic shock caused by myocardial infarction.
Results of the post-U.S. Food and Drug Administration-approval study with a continuous flow left ventricular assist device as a bridge to heart transplantation: a prospective study using the INTERMACS (Interagency Registry for Mechanically Assisted Circulatory Support).
Percutaneous short-term active mechanical support devices in cardiogenic shock: a systematic review and collaborative meta-analysis of randomized trials.
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.
LV mechanical unloading before culprit vessel reopening may reduce reperfusion injury and prime (biologically and mechanically) the myocardium for reperfusion, thus limiting infarct size and preventing subsequent adverse remodeling.
Implantation can usually be achieved within 5–10 minutes and should not exceedingly delay standard care.
Experience with the Impella device (Abiomed, Danvers, MA, USA) in stable patients with STEMI is limited, but preclinical studies have shown that the beneficial effect of acute LV unloading could be seen only when it is initiated 30 minutes before reperfusion but not within 15 minutes or after reperfusion.
Early initiation of hemodynamic support before PCI with Impella is associated with more complete revascularization and significantly improved survival in the setting of refractory CS complicating AMI,
whereas patients supported after PCI seem to have poor survival at 30 days. The Door to Unloading Trial (NCT03947619) will assess the impact of primary unloading before reperfusion vs standard care in AMI. The results of this ongoing trial will provide more definitive data on the role of acute MCS in combination with emergency PCI in patients with AMI.
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.
Acute left anterior descending coronary artery occlusion or left main lesions are often accompanied by acute HF (reduced LVEF, increased LV end-diastolic pressure) and CS with mortality exceeding 50%,
Temporal trends and outcomes of patients undergoing percutaneous coronary interventions for cardiogenic shock in the setting of acute myocardial infarction: a report from the CathPCI Registry.
2015 SCAI/ACC/HFSA/STS clinical expert consensus statement on the use of percutaneous mechanical circulatory support devices in cardiovascular care: endorsed by the American Heart Assocation, the Cardiological Society of India, and Sociedad Latino Americana de Cardiologia Intervencion; Affirmation of Value by the Canadian Association of Interventional Cardiology-Association Canadienne de Cardiologie d'intervention.
In progressive organ dysfunction owing to low CO, it seems intuitive to restore CO as quickly as possible without stressing the myocardium with catecholamines. Some acute MCS modalities can simultaneously unload the LV and augment CO.
For CS, a similar quality metric that reflects the time between the onset of CS and the initiation of acute MCS should be developed as the “door to support” time. Several recent reports support the concept of a door to support time, and have observed improved survival with early initiation of short-term MCS before PCI or before the initiation of inotropes and vasopressors in the setting of AMI-CS.
In AMI-CS, revascularization is immediately required along with early LV unloading. Even cases of preshock may be considered for short-term MCS facilitating a time to support concept.
Mechanical circulatory support in patients with cardiogenic shock in intensive care units: a position paper of the “Unité de Soins Intensifs de Cardiologie” group of the French Society of Cardiology, endorsed by the "Groupe Athérome et Cardiologie Interventionnelle" of the French Society of Cardiology.
In nonischemic CS treated with inotropes and vasopressors, acute MCS should be provided if first line therapy fails or either recovery or future cardiac replacement therapy (transplantation or LVAD) is being considered.
Recommendations for Timing According to Hemodynamic and Laboratory Parameters
Patients with CS should undergo a structured evaluation using right heart catheterization and echocardiography. Hemodynamic and echocardiographic evaluation may help to address the phenotype of the failing heart (eg, RV vs LV vs BiV failure).
Cardiac power output in watts, calculated as (CO × mean arterial pressure)/451, is the strongest independent hemodynamic correlate of in-hospital mortality in patients with CS. In the SHOCK trial, cardiac power output of 0.53 W or less was associated with a 58% in-hospital mortality rate. Advancing age and female sex are independently associated with lower cardiac power output.
Biomarkers are important for the diagnosis, monitoring, and management of patient with CS. Standard parameters such as serum lactate or serum creatinine are most useful. At rest, most cardiac energy results from beta-oxidation of fatty acids and pyruvate,
High lactate levels may reflect a stress response of the body with activation of the sympathetic nervous system, increased glycolysis, and a modified bioenergetic supply in patients with CS.
A peripheral oxygen demand–delivery mismatch will result in low central venous oxygen measurements. Serial measurements of arterial lactate and mixed venous oxygen saturation levels may be helpful to temporally monitor responses to therapeutic interventions. Arterial blood gas measurements also permit the assessment of arterial oxygenation and ventilation, as well as metabolic and respiratory acid–base status.
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.
Biomarkers of cardiac myonecrosis are useful to gauge the severity of acute underlying myocardial injury in conditions such as fulminant myocarditis. In AMI, cardiac troponin is noted to be elevated and has a rise-and-fall pattern consistent with acute ischemic injury.
N-terminal pro-B-type natriuretic peptide—a routinely used prognostic marker in HF—was not associated with short-term mortality in multivariable analysis in CS.
Growth-differentiation factor 15 and osteoprotegerin in acute myocardial infarction complicated by cardiogenic shock: a biomarker substudy of the IABP-SHOCK II-trial.
Therefore, early recognition of loss of function of single organs may be useful to assess prognosis and possibly for treatment decisions regarding timing of intervention with MCS. Acute kidney injury, which is reflected by a rise in serum creatinine and a potential reduction in urinary output in the setting of CS may indicate renal hypoperfusion and is associated with poor outcomes.
Growth-differentiation factor 15 and osteoprotegerin in acute myocardial infarction complicated by cardiogenic shock: a biomarker substudy of the IABP-SHOCK II-trial.
Prognostic impact of established and novel renal function biomarkers in myocardial infarction with cardiogenic shock: a biomarker substudy of the IABP-SHOCK II-trial.
Acute ischemic or congestive liver injury can occur in the setting of CS and manifests as a marked elevation in serum aspartate aminotransferase, alanine aminotransferase, bilirubin, and lactate dehydrogenase levels, often accompanied by an increase in prothrombin time. These patients have a 2.5-fold higher 30-day mortality than patients without acute liver injury.
A paradigm change has expanded the pathophysiology in CS from a simple low output syndrome to a more complex syndrome involving inflammation and nitric oxide production.
Cardiogenic shock complicating acute myocardial infarction–etiologies, management and outcome: a report from the SHOCK Trial Registry. SHould we emergently revascularize Occluded Coronaries for cardiogenic shocK?.
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.
Recommendations for Timing According to Scoring Systems
Multiple scoring systems to predict clinical outcomes in CS have been proposed (Table 1.4). Several models were derived in the general ICU population and include the Acute Physiology and Chronic Health Evaluation (APACHE)-II score and Simplified Acute Physiology Score (SAPS)-II scoring systems.
APACHE-II includes 13 physiological variables and was designed to be measured during the first 24 hours after ICU admission for patients more than 16 years of age. The APACHE-III scoring system adds variables such as pathogenesis of shock, sex, race, and comorbidities to the APACHE-II system and was validated in more than 17,000 ICU patients in the United States. The SAPS-II includes 12 physiological and 3 disease-related variables, was validated in 12,997 patients from 12 countries, and is used to predict in-hospital mortality. A small study comparing the APACHE-II, APACHE-III, SAPS-II, and the Sequential Organ Failure Assessment scoring systems in CS reported that APACHE-III and SAPS-II had the best mortality discrimination.
Predictive value of outcome scores in patients suffering from cardiogenic shock complicating AMI: APACHE II, APACHE III, Elebute-Stoner, SOFA, and SAPS II.
The CardShock study was a series of 219 patients with all-cause CS, and identified 7 variables associated with in-hospital mortality (c index 0.85). However, it lacked external validation.
Among patients with an acute coronary syndrome (ACS) complicated by CS, the Global Registry of Acute Coronary Events score has good discrimination and calibration for in-hospital and long-term mortality among all patients presenting with ACS, but it is not applicable to non-ACS presentations.
Limitations of available models include the lack of a CS-specific derivation population, external validation, dynamic application (ie, single point in time only), applicability to all CS types, and capture of all potentially prognostic clinical, laboratory, hemodynamic, imaging, and biomarker data.
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.
The SOFA (Sepsis-related Organ Failure Assessment) score to describe organ dysfunction/failure. On behalf of the Working Group on Sepsis-Related Problems of the European Society of Intensive Care Medicine.
Predicting the development of in-hospital cardiogenic shock in patients with ST-segment elevation myocardial infarction treated by primary percutaneous coronary intervention: the ORBI risk score.
Development and validation of a prognostic model for survival in patients treated with venoarterial extracorporeal membrane oxygenation: the PREDICT VA-ECMO score.
Identifying the preshock state is appealing as it may reduce mortality by preventing progression to overt CS through initiation of adequate management strategies. The best validated score in this setting is the recently introduced Observatoire Regional Breton sur l'Infarctus (ORBI) score to predict the development of CS.
Predicting the development of in-hospital cardiogenic shock in patients with ST-segment elevation myocardial infarction treated by primary percutaneous coronary intervention: the ORBI risk score.
Based on 11 routinely collected variables available in the catheterization laboratory, the ORBI score allowed independent prediction of the development of in-hospital CS after primary PCI (low risk, 0–7 points; low to intermediate risk, 8–10 points; intermediate to high risk, 11–12 points; high risk, >13 points). The score may be useful in the selection of high-risk patients in the setting of future randomized trials designed to provide a tailored aggressive management to preshock or patients with CS (Table 1.4).
Currently, the only CS score with both internal and external validation is derived from the Intraaortic Balloon Pump in Cardiogenic Shock II (IABP-SHOCK II) trial.
Based on 6 variables—including the biomarkers lactate, creatinine and glucose—with a maximum of 9 points, the IABP-SHOCK II score divides patients into 3 risk groups. Patients in the low (0–2 points), intermediate (3 or 4 points), and high-risk categories (5–9 points) have 30-day mortality risk of 20%–30%, 40%–60%, and 70%–90%, respectively. This score may also be a suitable tool to tailor more aggressive treatment strategies such as acute MCS. However, this requires further validation in randomized trials.
Several risk scores have been proposed for assessing the likelihood of survival to hospital discharge in patients with ECMO, such as Predicting Death for Severe ARDS on VV-ECMO (PRESERVE),
Predicting survival after extracorporeal membrane oxygenation for severe acute respiratory failure. The Respiratory Extracorporeal Membrane Oxygenation Survival Prediction (RESP) score.
Development and validation of a prognostic model for survival in patients treated with venoarterial extracorporeal membrane oxygenation: the PREDICT VA-ECMO score.
Only the SAPS II and the SAVE score were found to be suitable specifically for short- and long-term outcome prediction in this vulnerable patient population.
Biomarkers have been incorporated in both scores. These multiparametric scores can assist the HF team in arriving at comprehensive risk assessments to inform decisions. However, there are several important considerations and limitations that are often overlooked when applying these tools in clinical settings and in clinical trial design, including the fact that these risk scores have modest discrimination at best.
In light of the high in-hospital mortality, costs, and ethical issues, appropriate patient selection for MCS requires careful consideration of the aforementioned factors.
Requirements for the Use of MCS in Acute CS
Many hospitals have developed multidisciplinary care teams for patients with AMI-CS. Cardiac surgeons, interventional cardiologists, advanced HF cardiologists and critical care specialists have collaborated to institute shock teams. These teams are based on several requirements: (1) the multidisciplinary approach must be maintained on every patient, (2) consistent treatment options must be available 24 hours a day and 7 days a week, (3) team members should ideally commit to rounds with representation from each member specialty, and (4) information must flow to all team members in a timely manner.
Shock Team Coordination, Notification, and Communication
The most important aspect of team-based care of the CS patient is the relational coordination of the multidisciplinary team, not the management of materials or resources. The shock team evaluation of patients with CS begins with multidisciplinary team notification, and assessment and information must continue to flow to team members with changes in status and care in a timely manner. Initial presentation may be accomplished through a central referral center with some or all team members receiving the initial information and determining suitability for treatment/transfer. This assessment may suggest an initial treatment strategy and determine the receiving location (ICU, catheterization laboratory, or operating room). Once the decision is made to accept and treat, the multidisciplinary team evaluates the patient and formulates further treatment strategy.
Adapted from the American College of Cardiology/American Heart Association Clinical Practice Guideline Recommendation Classification system.
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