What are the key considerations for managing a patient with severe cardiac dysfunction requiring Impella (intra-aortic balloon pump) support in the ICU, including those with a history of cardiac surgery or comorbidities like diabetes or hypertension?

Impella ICU Management: Key Considerations

Initial Assessment and Patient Selection

Impella should be considered in refractory cardiogenic shock when patients fail to stabilize with pharmacological therapy (inotropes and vasopressors), but only after careful exclusion of contraindications and assessment of candidacy for mechanical circulatory support. 1, 2

Absolute Contraindications to Screen For:

• Left ventricular thrombus 2
• Severe aortic stenosis 2
• Significant aortic insufficiency 2
• Severe peripheral artery disease 2
• Aortic dissection 2

Pre-Implantation Hemodynamic Criteria:

• Systolic blood pressure <90 mmHg despite adequate volume status 1
• Signs of hypoperfusion: oliguria (<0.5 ml/kg/h for ≥6 hours), altered mentation, cool extremities with livedo reticularis 1
• Lactate >2-4 mmol/L 1
• Cardiac power output assessment via pulmonary artery catheter 1

Device Selection Algorithm

Choose the Impella model based on body surface area, degree of shock severity, and whether biventricular support is needed. 2, 3

Left Ventricular Support Options:

• Impella 2.5: Provides up to 2.5 L/min flow; may be inadequate for patients with large body mass index or severe cardiogenic shock 2
• Impella CP: Intermediate flow capacity
• Impella 5.0: Provides 5.0-5.5 L/min; faster recovery of microcirculation and cardiac function than Impella 2.5 2, 3

Right Ventricular Support:

• Impella RP: Specifically designed for right ventricular failure; provides hemodynamic improvement with increase in cardiac index from 1.9 to 3.1 L/min/m² and decrease in CVP from 19 to 13 mmHg 2, 4
• Consider for post-LVAD RVF, post-cardiotomy RVF, or RV failure complicating MI 4

Anticoagulation Protocol

Initiate unfractionated heparin bolus of 100 U/kg (maximum 5000 U) at time of implantation to prevent pump thrombosis. 2

Critical Monitoring:

• Severe bleeding occurs in 8.5% vs 3.0% with IABP 2
• Vascular complications occur in 9.8% vs 3.8% with IABP 2
• Balance thrombotic risk against bleeding risk through serial hemoglobin monitoring and vascular access site assessment 2

Hemodynamic Management During Support

Target mean arterial pressure >65 mmHg and monitor cardiac output, cardiac index, and end-organ perfusion markers continuously. 2

Vasopressor Selection:

• Preferred: Vasopressin or norepinephrine (increase systemic afterload without significantly increasing pulmonary vascular resistance) 2
• Avoid: Excessive inotrope use that increases myocardial oxygen demand 2

Motor Current Monitoring:

• Motor current reflects work required to overcome pressure gradient 2
• High motor current with low flow suggests suction events (device inlet obstruction) 2
• Monitor for aortic insufficiency development with prolonged support 2

Fluid Management Strategy

Administer initial fluid challenge of 200-250 mL crystalloid over 10-30 minutes only if no overt volume overload is present; if no hemodynamic response occurs, immediately initiate inotropic support rather than additional fluids. 5

Critical Error to Avoid:

• Never assume cardiogenic shock requires aggressive fluid resuscitation like other shock states 5
• If systolic BP remains <90 mmHg after fluid challenge, start dobutamine immediately 5
• If hypotension persists despite inotropes, add norepinephrine—not more fluids 5

Escalation Strategy for Deteriorating Patients

When patients worsen despite Impella support, immediately assess for device malfunction, inadequate flow capacity, and consider escalation to higher-flow models or alternative mechanical circulatory support. 2

Biventricular Failure:

• Add Impella RP to create bilateral Impella support 2
• Consider VA-ECMO with LV venting (maintain Impella or add IABP) 2
• VA-ECMO alone increases LV afterload and may cause ventricular distension without venting 2

Right Ventricular Predominance:

• Impella RP provides 72% survival at 30 days in severe RVF 4
• Mean support duration 4.0 days 4

Weaning Protocol

Assess for improvements in left ventricular function through serial echocardiographic evaluations and resolution of mechanical complications before weaning. 2

Prognostic Indicators:

• Residual cardiac function >1 L/min above pump flow: 10% mortality 6
• Residual cardiac function ≤1 L/min above pump flow: 88% mortality 6
• Lactate clearance and cardiac power output guide weaning strategies 1

Failed Weaning:

• Consider longer support duration 2
• Transition to more durable mechanical circulatory support devices 2
• Assess candidacy for durable VAD or cardiac transplantation 1

Multidisciplinary Team Requirements

All cardiogenic shock patients requiring Impella should be managed in a level 1 shock center with 24/7 cardiac catheterization capability, dedicated ICU, and availability of short-term mechanical circulatory support. 1

Essential Team Composition:

• Interventional cardiologist 1
• Cardiothoracic surgeon 1
• Cardiac intensivist 1
• Advanced heart failure specialist 1

Vascular Access Expertise:

• Axillary artery access for patients with prohibitive iliofemoral vasculature 1
• Facilitates earlier ambulation and improved nutritional status during prolonged support 1

Comorbidity Considerations

Post-Cardiac Surgery:

• Impella reduces mortality in postcardiotomy low-output syndrome when residual cardiac function is adequate 6
• 54% mortality overall, but only 10% when cardiac output increases ≥1 L/min above pump flow 6

Diabetes and Hypertension:

• These comorbidities influence candidacy for durable MCS or transplantation 1
• Age, comorbidities, and neurological function determine appropriateness of mechanical circulatory support escalation 1

Outcomes Data

Overall 30-day survival is 67-72% with Impella support in severe cardiogenic shock, with survivors less likely to require mechanical ventilation or continuous renal replacement therapy. 2, 4

• 85% survival to device explantation when used early in AMI-CS 2
• 68.8% survive to next therapy (durable MCS, transplant, or recovery) 2
• Median duration of support: 7 days 2