What is the Impella 5.5 (Intra-Aortic Balloon Pump)?

From the Guidelines

The Impella 5.5 should be considered for use in patients with acute myocardial infarction complicated by cardiogenic shock, particularly those with persistent clinical hypoperfusion, hypotension, vasopressor requirement, or cardiac power output <0.6 W despite adequate filling pressures, as it may provide hemodynamic support and improve outcomes 1.

Key Points

• The Impella 5.5 is a microaxial heart pump that provides up to 5.5 liters per minute of blood flow, supporting the heart's function by unloading the left ventricle and increasing cardiac output 1.
• It is indicated for use in cardiogenic shock, high-risk percutaneous coronary interventions, and as a bridge to recovery, transplant, or durable left ventricular assist device implantation 1.
• Patients with the device require anticoagulation therapy, typically with heparin to maintain an activated clotting time of 160-180 seconds, and careful monitoring for complications such as bleeding, vascular injury, hemolysis, and infection 1.
• The device's effectiveness stems from its ability to reduce myocardial workload while maintaining vital organ perfusion, potentially allowing the heart time to recover from acute injury 1.

Considerations

• The timing of device insertion is crucial, with some studies suggesting that early insertion may be beneficial 1.
• The choice of device should be individualized based on patient characteristics and the specific clinical scenario 1.
• Close monitoring for complications and adjustment of anticoagulation therapy as needed is essential 1.

Outcomes

• Observational studies have reported variable results, with some showing improved survival with Impella use 1.
• However, randomized controlled trials have not shown a significant reduction in mortality with Impella use compared to other devices or conservative management 1.
• Further studies are needed to fully understand the clinical utility of the Impella 5.5 in cardiogenic shock and other clinical scenarios 1.

From the Research

Impella 55 Overview

• The Impella 5.5 device is a surgically inserted, trans-valvular, microaxial flow device capable of providing 5.5 L/min of continuous, antegrade flow from the left ventricle (LV) to the aorta 2.
• It is used for mechanical circulatory support in patients with cardiogenic shock or those undergoing high-risk percutaneous coronary intervention (PCI) 3, 4.

Clinical Applications

• The Impella 5.5 device is used in various clinical scenarios, including escalation of support for acute myocardial infarction cardiogenic shock (AMICS), transition from extracorporeal membrane oxygenation to mobile support, bridge to transplantation or durable MCS in acute decompensated heart failure, or perioperative use in post-cardiotomy cardiogenic shock (PCCS) 2.
• It allows for monitoring of left-heart recovery, optimizing right ventricular function, and rehabilitating patients to meet bridging endpoints 2.

Anticoagulation Protocols

• Anticoagulation protocols for patients with Impella devices are not well established and are complicated by concomitant use of purge solutions containing unfractionated heparin (UFH) and intravenous UFH continuous infusion (CI) for systemic anticoagulation 3.
• A modified UFH protocol targeting an anti-Xa goal of 0.3 to 0.5 units/mL may be a useful approach to achieve therapeutic anticoagulation while accounting for UFH exposure from the purge solution and minimizing need for frequent calculations 3.
• Lowering UFH-targets in left-Impella supported cardiogenic shock patients seems to be a safe and promising strategy for reducing major bleedings without increasing major cardiovascular and cerebrovascular adverse events (MACCE) 5.

Safety and Effectiveness

• The use of Impella devices has been shown to be effective in managing patients with cardiogenic shock and high-risk PCI, with improved survival rates compared to historical mortality rates 4.
• However, thromboembolic and bleeding events are frequent during percutaneous mechanical circulatory support (pMCS), and optimal anticoagulation regimes are still being explored 5.
• The Impella 5.5 device has been shown to have a low rate of thrombotic events, with a rate of overall thrombosis of 4.9% in one study 3.