Can Impella (percutaneous left ventricular assist device) be used in patients with end-stage renal disease (ESRD) on continuous renal replacement therapy (CRRT) who develop cardiogenic shock, even in the absence of true cardiogenic causes?

Can Impella Be Used in Non-Primary Cardiogenic Causes?

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. 1

Defining the Indication: Hemodynamic Profile Over Etiology

The key determinant for Impella use is the hemodynamic state (hypotension with SBP <90 mmHg despite adequate filling and signs of hypoperfusion), not the primary disease process. 1 The 2016 ESC guidelines explicitly state that cardiogenic shock scenarios "range 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." 1

Critical Assessment Points:

• Verify true cardiogenic shock physiology: Confirm adequate preload (not hypovolemia from ultrafiltration/CRRT), assess cardiac output/index via pulmonary artery catheter, and document end-organ hypoperfusion (elevated lactate, oliguria, altered mental status) 2
• Distinguish from distributive shock: ESRD patients may have mixed shock states; ensure the primary driver is cardiac dysfunction rather than sepsis or vasodilatory shock 2
• Echocardiographic confirmation: Document left ventricular systolic dysfunction as the primary mechanism requiring support 1

Specific Considerations for ESRD Patients on CRRT

Feasibility and Outcomes:

Research specifically examining Impella in ESRD patients on CRRT demonstrates that AKI requiring renal replacement therapy does not preclude Impella use and may actually improve outcomes. 3 In a retrospective study of 34 cardiogenic shock patients on Impella-CP, those with AKI who received RRT had 30-day mortality of 22.2%, comparable to patients without AKI (30.8%), while those with AKI who did not receive RRT had significantly higher mortality at 75.0%. 3

Practical Management Points:

• Anticoagulation complexity: Initial UFH bolus of 100 U/kg (maximum 5000 U) is required for Impella, which must be carefully balanced with bleeding risk in CRRT patients 2
• Volume status optimization: CRRT allows precise volume management, which is advantageous for maintaining optimal Impella function and preventing suction events 2
• Monitor for venous congestion: Elevated central venous pressure independently predicts AKI development (OR 1.216, p=0.02) and should be aggressively managed 4

Absolute Contraindications That Must Be Excluded

Regardless of etiology, Impella is contraindicated in: 2

• Left ventricular thrombus
• Severe aortic stenosis or significant aortic insufficiency
• Severe peripheral artery disease preventing femoral access
• Aortic dissection

Bridge-to-Decision Strategy in Complex Patients

For ESRD patients with multiorgan failure, Impella serves as a bridge-to-decision device, with 68.8% of severe cardiogenic shock patients surviving to next therapy (durable MCS, transplant, or recovery). 2, 5 The median support duration is 7 days, providing time to assess: 5

• Neurologic recovery potential
• Candidacy for durable support or transplantation
• Myocardial recovery trajectory

Prognostic Indicators During Support:

Survivors are significantly less likely to require mechanical ventilation (p=0.049) or CRRT (p<0.001) at baseline, though baseline demographics alone do not predict survival. 5 Monitor for improvement in tissue perfusion markers (lactate clearance, central venous oxygen saturation >70%) as these independently predict outcomes. 4

When to Escalate Beyond Impella

If the patient deteriorates despite Impella support in the setting of ESRD/CRRT: 2

• Biventricular failure: Add Impella RP for right ventricular support or transition to VA-ECMO with Impella maintained as LV venting mechanism
• Inadequate flow capacity: Upgrade from Impella 2.5 (2.5 L/min) to Impella CP (3.5 L/min) or 5.0 (5.0-5.5 L/min) based on body habitus and hemodynamic requirements 2
• Persistent hypoperfusion: Consider VA-ECMO, which provides biventricular support but requires LV venting to prevent distension 1, 2

Common Pitfalls to Avoid

• Assuming ESRD is a contraindication: No guideline lists ESRD or CRRT as contraindications; focus on cardiac anatomy and hemodynamics 1, 2
• Delaying RRT in AKI: Early RRT initiation in Impella patients with AKI improves survival; do not withhold dialysis 3
• Overlooking vascular complications: Impella has higher rates of vascular complications (9.8%) and bleeding (8.5%) compared to IABP, requiring meticulous access site management 1
• Inadequate anticoagulation monitoring: Pump thrombosis risk necessitates strict UFH protocols despite bleeding concerns in CRRT patients 2