Is the Impella (Intra-Aortic Balloon Pump) a temporary ventricular assist device?

Impella as a Temporary Ventricular Assist Device

Yes, the Impella is a nondurable, temporary ventricular assist device designed for short-term circulatory support. 1

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 1
• It is inserted via a peripheral artery and positioned across the aortic valve to pump blood from the left ventricle to the ascending aorta 2
• The device functions similarly to other left ventricular assist devices (LVADs) by providing left ventricular drainage and aortic blood delivery, but in a catheter-based format 2

Available Models and Capabilities

• Impella 2.5: Provides up to 2.5 L/min of flow, can be inserted percutaneously in the catheterization laboratory 1
• Impella 5.0/5.5: Larger devices capable of delivering 5-6.2 L/min flow, requiring surgical cut-down on a peripheral artery for insertion 1, 3
• Impella RP: Designed specifically for right ventricular support 1

Duration of Support

• The Impella is FDA-approved for temporary circulatory support 1
• While originally designed for shorter durations, newer models like the Impella 5.5 have been used for extended periods (median 10 days, with cases reported up to 83 days) 4, 3
• The FDA has approved the Impella 5.5 for up to 14 days of support 3

Clinical Applications

• Cardiogenic shock, particularly following acute myocardial infarction 1, 2
• High-risk percutaneous coronary interventions 1, 2
• Postcardiotomy shock 3
• Bridge to recovery, durable device, or heart transplantation 2, 4
• Left ventricular venting in patients supported with veno-arterial extracorporeal membrane oxygenation (VA-ECMO) 2

Advantages and Limitations

Advantages:

• Provides immediate and sustained unloading of the left ventricle while increasing systemic cardiac output 5
• Allows straightforward percutaneous insertion and rapid initiation of circulatory support 1
• Minimally invasive implantation reduces bleeding and enables earlier patient ambulation 4

Limitations:

• Maximum flow limitations (particularly for Impella 2.5) may be inadequate for patients with large body mass index or severe cardiogenic shock 1
• Potential complications include bleeding, thrombosis, and limb ischemia 1
• Contraindicated in patients with left ventricular thrombus, aortic stenosis, severe peripheral artery disease, or aortic disease 1

Comparison to Other Temporary Support Devices

• Unlike Intra-Aortic Balloon Pump (IABP), which provides minimal hemodynamic support, Impella devices offer greater left ventricular support 1
• Compared to TandemHeart, which requires transseptal puncture, the Impella has a simpler design and implantation procedure 1
• VA-ECMO provides biventricular support but may require additional left ventricular venting (potentially using an Impella) to prevent left ventricular distension 1

Clinical Evidence

• Observational studies and registry data suggest potential value in reducing mortality associated with cardiogenic shock 5, 3
• In the first 200 US patients treated with Impella 5.5, overall survival to explant was 74%, with better outcomes in cardiomyopathy cases (80%) compared to post-cardiotomy cardiogenic shock (57.6%) 3
• However, randomized controlled trial data supporting mortality benefit remains limited 2, 5

The Impella represents an important option in the armamentarium of temporary mechanical circulatory support devices, offering a balance between invasiveness and hemodynamic support for patients requiring short to intermediate-term cardiac assistance.