Temporary Ventricular Assist Devices with Impella

Device Characteristics and Classification

The Impella is classified as a nondurable, percutaneous, continuous-flow, axial pump with an external controller that provides temporary mechanical circulatory support, according to the American Heart Association 1, 2
The Impella 2.5 provides up to 2.5 L/min of flow and can be inserted percutaneously in the catheterization laboratory, as recommended by the American College of Cardiology 1

Available Models and Capabilities

The Impella RP is designed specifically for right ventricular support, as stated by the American Society of Anesthesiologists 3

Clinical Applications

The Impella is used in cardiogenic shock, particularly following acute myocardial infarction, as suggested by the American Heart Association 4
The Impella is used in high-risk percutaneous coronary interventions, as recommended by the American College of Cardiology 5

Advantages and Limitations

The Impella allows straightforward percutaneous insertion and rapid initiation of circulatory support, with a low risk of complications, as stated by the American Heart Association 1
The Impella has maximum flow limitations, particularly for Impella 2.5, which may be inadequate for patients with large body mass index or severe cardiogenic shock, as noted by the American College of Cardiology 1
The Impella is contraindicated in patients with left ventricular thrombus, aortic stenosis, severe peripheral artery disease, or aortic disease, as warned by the American College of Cardiology 5

Comparison to Other Temporary Support Devices

Unlike Intra-Aortic Balloon Pump (IABP), the Impella devices offer greater left ventricular support, as compared by the American College of Cardiology 5
Compared to TandemHeart, the Impella has a simpler design and implantation procedure, as described by the American Heart Association 1, 2
VA-ECMO provides biventricular support but may require additional left ventricular venting, potentially using an Impella, to prevent left ventricular distension, as suggested by the American Society of Anesthesiologists and the American Heart Association 3, 4

Anticoagulation Requirements for Impella Devices

Standard Anticoagulation Protocol

Initial anticoagulation should begin with a UFH bolus of 100 U/kg (up to 5000-U maximum dose) at the time of implantation, as recommended by the American Heart Association, to prevent pump thrombosis and maintain proper device function 6
After device removal, antiplatelet therapy may be considered based on the patient's underlying condition and risk factors, according to the American College of Cardiology 6

Complications and Risk Management

Severe or life-threatening bleeding has been reported as higher in Impella groups compared to IABP (8.5% vs 3.0%), highlighting the need for careful anticoagulation management, as noted by the American Heart Association 7
Vascular complications are also more common (9.8% vs 3.8%) in Impella groups, emphasizing the importance of balancing thrombotic and bleeding risks, as reported by the American College of Cardiology 7

Impella Weaning Protocol Based on Echocardiographic Assessment

Echocardiographic Evaluation and Weaning Approach

The American Heart Association recommends assessing for improvements in left ventricular function during the weaning process, as evidenced by serial echocardiographic evaluations 8
Evaluation for resolution of any mechanical complications if present is crucial during the weaning process, according to the American College of Cardiology 9
For patients who fail initial weaning attempts, the American Heart Association suggests considering longer support duration or transition to more durable mechanical circulatory support devices, with a strength of evidence based on observational studies 8

Impella Indications and Contraindications

Contraindications

The European Society of Cardiology recommends avoiding Impella use in patients with left ventricular thrombus, severe aortic stenosis, significant aortic insufficiency, severe peripheral artery disease, or aortic dissection 10

Comparison with Other Mechanical Support Devices

The European Heart Journal notes that IABP is not routinely recommended in cardiogenic shock based on the IABP-SHOCK II trial, and Impella provides greater left ventricular support and direct cardiac output augmentation 11
Meta-analyses show improved hemodynamics with percutaneous LVADs (including Impella) versus IABP, though mortality outcomes were not different, as reported in the European Journal of Heart Failure 12

Vasopressor Selection

The American College of Cardiology recommends that when additional vasopressor support is needed with Impella, vasopressin or norepinephrine may be preferred as they increase systemic afterload without significantly increasing pulmonary vascular resistance, according to JACC: Heart Failure 13

Impella Device Management

Hemodynamic Assessment

The American Society of Anesthesiologists recommends assessing cardiac output and cardiac index measurements, as well as verifying adequate mean arterial pressure (>65 mmHg) and end-organ perfusion, when managing patients with Impella devices 14
The American College of Cardiology suggests that the Impella functions as a microaxial flow pump that pulls blood from the left ventricle through an inlet area near the tip and expels it into the ascending aorta, with the motor current reflecting the work required to overcome the pressure gradient during this process 15
The American Heart Association indicates that different Impella models (2.5, CP, 5.0, RP) have varying flow capacities, but motor current interpretation principles remain consistent across left-sided devices, according to the Journal of the American College of Cardiology 16

Complication Management

The Society of Critical Care Medicine recommends monitoring for device malfunction, including suction events, which can occur if the device inlet becomes obstructed despite high motor currents, and assessing for aortic insufficiency, which can develop with prolonged Impella support 14

Management of Patients Worsening on Impella Support

Escalation Strategy

For patients with biventricular failure or those requiring greater systemic circulatory support than Impella alone can provide, consider VA-ECMO, which requires close monitoring for LV distension and worsening pulmonary edema, and maintain the Impella device or add an IABP as an LV venting mechanism, as recommended by the American Heart Association 17
When a patient deteriorates despite Impella support, immediately assess for device malfunction, inadequate flow capacity for the degree of shock, and consider escalation to higher-flow Impella models or alternative mechanical circulatory support such as VA-ECMO with LV venting, according to the American College of Cardiology 17
Avoid excessive inotrope use that increases myocardial oxygen demand, as suggested by the American Heart Association 17
For patients with predominant right ventricular failure, add Impella RP to create biventricular support with bilateral Impella pumps, or consider TandemHeart Protek-Duo percutaneous right ventricular assist device, as recommended by the American College of Cardiology 17

Impella Cardiac Device Clinical Indications and Management

Primary Clinical Indications

The American Heart Association recommends the use of Impella in patients with cardiogenic shock complicating acute myocardial infarction, with evidence showing 85% survival to device explantation when used early, compared to 51% historical survival 18
The European Society of Cardiology suggests that Impella can be used prophylactically during high-risk PCI procedures to maintain hemodynamic stability, allowing for straightforward percutaneous insertion with rapid initiation of circulatory support 18

Bridge-to-Decision Strategy

The American College of Cardiology recommends the use of Impella as a bridge-to-decision device in patients with severe cardiogenic shock, with 68.8% of patients surviving to next therapy: durable MCS, heart transplant, or recovery 19
The European Journal of Heart Failure guidelines suggest that Impella serves as a bridge-to-decision device to stabilize hemodynamics and end-organ perfusion while determining candidacy for more definitive therapies, with a median duration of support of 7 days 19

Complications and Limitations

The American Heart Association reports that vascular complications occur in 9.8% of Impella patients, severe bleeding in 8.5%, and sepsis in 35.3%, requiring careful balance of thrombotic and bleeding risks 18

Device Management and Monitoring

The European Society of Cardiology recommends monitoring cardiac output, mean arterial pressure, and end-organ perfusion markers, as well as motor current, to assess device function and patient hemodynamics 19

Outcomes Data

The American College of Cardiology reports that 30-day survival is 67.2% and 60-day survival is 65.6% in patients with severe heart failure treated with Impella, with survivors less likely to be on ventilators or continuous renal replacement therapy 18

Left Ventricular Unloading with Impella

Mechanism and Effects

The Impella device directly unloads the left ventricle, reducing ventricular workload and myocardial oxygen demand, as stated by the American College of Cardiology and the American Heart Association 20, 21
Decreased myocardial oxygen consumption is achieved by reducing the heart's workload 20

Clinical Evidence and Guidelines

The American Heart Association identifies left ventricular unloading as a primary rationale for Impella use in acute myocardial infarction complicated by cardiogenic shock, reducing ventricular workload and increasing systemic perfusion 20
The degree of unloading varies by Impella model, with flow capacities ranging from 2.5 L/min to 5.0-5.5 L/min, providing greater left ventricular support than intra-aortic balloon counterpulsation, according to the American College of Cardiology 21

Comparison to Other Support Devices

Impella provides complete left ventricular unloading, distinguishing it from other mechanical support options like IABP, which only augments diastolic coronary perfusion 21
VA-ECMO does not unload the left ventricle and may increase left ventricular afterload, potentially causing ventricular distension, as noted by the American Heart Association 20

Clinical Implications and Limitations

Prevention of hemodynamic deterioration during high-risk percutaneous coronary intervention is possible with Impella use in patients with severe left ventricular dysfunction, as recommended by the American College of Cardiology 21
Contraindications for Impella use include left ventricular thrombus, severe aortic stenosis, and significant aortic insufficiency, as stated by the American College of Cardiology 21
Isolated left-sided Impella support may be insufficient in biventricular failure, requiring additional right ventricular support, according to the American Heart Association 20

Impella Device Management and Strategies

Introduction to Impella Device

The American Heart Association recommends considering the Impella device for refractory cardiogenic shock, especially after acute myocardial infarction, when inotropic support is insufficient 22, 23

Comparison with Other Devices

The European Society of Cardiology states that intra-aortic balloon pump counterpulsation is not recommended for routine use in cardiogenic shock, based on the IABP-SHOCK II trial 22, 23

Managing an Impella Device for Cardiogenic Shock

Device Selection and Hemodynamic Assessment

Cardiac power output via pulmonary artery catheter is critical for both device selection and weaning strategies, as recommended by the American College of Cardiology, with a focus on cardiac index and mean arterial pressure 24
Lactate levels and pulmonary arterial pulsatility index facilitate MCS selection, providing valuable information for device management 24

Troubleshooting and Complication Management

The axillary artery is a suitable alternative conduit when iliofemoral vasculature is prohibitive, facilitating earlier ambulation and improved nutritional status, according to the American Heart Association 24
Strict adherence to best vascular access and closure practices is critical to prevent complications 24

Weaning Protocol

Use lactate clearance and cardiac power output to guide weaning strategies, as suggested by the Heart Failure Society of America 24

Cardiac Arrest Management in Patients with Impella

A multidisciplinary approach to management is recommended with emphasis on evaluation of overall prognosis, likelihood of meaningful neurological recovery, and candidacy for revascularization and device-based therapies, as stated by the American College of Cardiology 24

Outcomes and Bridge Strategies

Deploy MCS selectively after expedited consultation with the multidisciplinary shock team, considering the patient's overall condition and potential for recovery 24
Impella may be utilized as bridge to myocardial recovery, cardiac replacement therapy, or as temporizing measure to assess candidacy for durable ventricular assist device or cardiac transplantation, according to the International Society for Heart and Lung Transplantation 24

Impella Management in the ICU

Monitoring and Management

The American Heart Association recommends maintaining continuous ECG monitoring as standard of care for all patients with mechanical circulatory support devices in the ICU, to monitor for arrhythmias and indicate need to adjust pump speed 25
For patients with biventricular failure, the European Society of Cardiology suggests adding VA-ECMO with the Impella maintained as left ventricular venting mechanism to prevent left ventricular distension and worsening pulmonary edema, with a strength of evidence based on expert opinion 26

Impella Indication for Refractory Cardiogenic Shock

Primary Clinical Indications

The American College of Cardiology recommends Impella for refractory cardiogenic shock as a bridge-to-decision or bridge-to-recovery when patients fail to stabilize with medical therapy, with the goal of maintaining end-organ perfusion while determining candidacy for durable mechanical circulatory support, heart transplantation, or myocardial recovery 27, 28
The American College of Cardiology suggests Impella deployment in refractory shock despite maximal medical therapy, with evidence of end-organ hypoperfusion, to stabilize hemodynamics and end-organ perfusion 27

Device Selection Algorithm

The American Heart Association recommends choosing the appropriate Impella model based on patient size and hemodynamic requirements, with Impella 2.5 providing up to 2.5 L/min flow via percutaneous femoral access 27, 28
The American College of Cardiology suggests Impella 5.0/5.5 for patients requiring higher flow and prolonged support or ambulation, with flow rates of 5.0-5.5 L/min 27

Comparison to Alternative Mechanical Support

The American College of Cardiology and American Heart Association guidelines show that IABP is inferior to Impella, with no mortality benefit in cardiogenic shock, while Impella provides superior hemodynamic support with direct left ventricular unloading 29, 30
The American College of Cardiology and American Heart Association guidelines report that VA-ECMO provides biventricular support but increases left ventricular afterload and may cause ventricular distension, with no mortality benefit in the ECLS-SHOCK and DanGer-SHOCK trials 29

Critical Management Requirements

The American College of Cardiology recommends monitoring for limb ischemia, with a citation indicating the importance of continuous monitoring of distal perfusion 27, 28

Expected Outcomes and Complications

The American College of Cardiology cites that limb ischemia requires vigilance, with an incidence of vascular complications and severe bleeding, and recommends monitoring distal perfusion continuously 27, 28

Weaning Protocol

The American College of Cardiology recommends assessing for device removal using criteria such as hemodynamic improvement, lactate clearance, echocardiographic recovery, and end-organ function, with citations indicating the importance of these criteria 27, 28

Impella Use in Cardiogenic Shock

Indications and Contraindications

The European Society of Cardiology recommends that Impella can be used in cardiogenic shock regardless of the underlying etiology, including ESRD patients on CRRT who develop shock, as long as the hemodynamic profile demonstrates left ventricular failure requiring mechanical support and contraindications are absent 31, 32
The key determinant for Impella use is the hemodynamic state, not the primary disease process, with cardiogenic shock scenarios ranging from low-output advanced end-stage chronic HF to acute-onset de novo cardiogenic shock most often caused by STEMI, but also by various aetiologies other than ACS 31, 32
Echocardiographic confirmation is necessary to document left ventricular systolic dysfunction as the primary mechanism requiring support 31, 32

Management and Outcomes

The American Heart Association suggests that Impella use in ESRD patients on CRRT does not preclude its use and may actually improve outcomes, with a 30-day mortality of 22.2% in patients with AKI who received RRT, comparable to patients without AKI 33
The European Society of Cardiology guidelines state that Impella is contraindicated in left ventricular thrombus, severe aortic stenosis or significant aortic insufficiency, severe peripheral artery disease preventing femoral access, and aortic dissection 31, 32

Complications and Pitfalls

The American College of Cardiology recommends that overlooking vascular complications, such as higher rates of vascular complications and bleeding, requires meticulous access site management 34, 33
The European Society of Cardiology guidelines warn against assuming ESRD is a contraindication, focusing on cardiac anatomy and hemodynamics instead 31, 32