Mechanical Circulatory Support Devices

Mechanical circulatory support devices are pumps and related technologies that take over part of the heart's work to maintain blood flow when the native circulation fails. They range from the intra-aortic balloon pump to percutaneous and surgically implanted ventricular assist devices, and they are used to bridge patients through severe pump failure toward recovery, further decisions, or transplantation.

Definition

Mechanical circulatory support comprises devices that mechanically augment or substitute for the pumping function of the heart to sustain systemic and organ perfusion when cardiac output is critically inadequate.

Scope

The entry covers the major categories of mechanical circulatory support short of full extracorporeal membrane oxygenation — counterpulsation, percutaneous flow pumps, and durable ventricular assist devices — the rationale behind each, and the trial evidence that has tested them in cardiogenic shock and advanced heart failure. It is a reference description of these device classes, not guidance on selecting or operating a device.

Core questions

• What different mechanisms do mechanical support devices use to augment the circulation?
• How do temporary percutaneous devices differ from durable implanted devices?
• What does trial evidence show about device support in cardiogenic shock?

Key concepts

• Intra-aortic balloon counterpulsation
• Percutaneous microaxial flow pumps
• Ventricular assist devices
• Temporary versus durable support
• Bridge to recovery, decision, or transplantation
• Afterload and ventricular unloading

Mechanisms

Mechanical support devices augment the circulation through different physical principles. The intra-aortic balloon pump inflates and deflates in time with the cardiac cycle to improve coronary perfusion and reduce the resistance the heart pumps against. Microaxial flow pumps and other percutaneous assist devices draw blood from the ventricle and expel it into the aorta, directly adding forward flow and unloading the ventricle. Durable ventricular assist devices, surgically implanted, take over much of one ventricle's output for longer periods. Across these devices, the shared aims are to restore systemic perfusion and to reduce the workload on the failing heart while its underlying problem is addressed.

Clinical relevance

These device classes show how the circulation can be mechanically supported when drugs are insufficient, and the trials testing them form part of the evidence clinicians appraise in cardiogenic shock and advanced heart failure. This entry describes the devices and their evidence base as a reference; it does not provide criteria for selecting or managing a device in an individual patient.

Epidemiology

Use of mechanical circulatory support has evolved with device technology and trial evidence: routine intra-aortic balloon counterpulsation in infarct-related shock declined after neutral trial results, while newer percutaneous and durable devices have been adopted in selected settings. Patterns of use vary by center and by indication.

Evidence & guidelines

The IABP-SHOCK II trial (Thiele et al., 2012) found no survival benefit from routine intra-aortic balloon counterpulsation in infarct-related cardiogenic shock, and the DanGer Shock trial (Møller et al., 2024) tested a microaxial flow pump in the same setting. The SCAI shock classification (Baran et al., 2019) and society heart-failure guidelines such as the 2021 ESC guidelines (McDonagh et al., 2021) place these devices within the broader management framework.

History

Mechanical circulatory support began with the intra-aortic balloon pump, long the default device in cardiogenic shock, and expanded as percutaneous flow pumps and durable ventricular assist devices were developed. Randomized trials in the 2010s and 2020s tested whether these devices improve survival, and their results — neutral for routine balloon counterpulsation and more nuanced for newer pumps — reshaped how the devices are used and understood.

Debates

Do mechanical support devices improve survival in cardiogenic shock?

The neutral result for routine intra-aortic balloon counterpulsation and the more nuanced findings for newer flow pumps have left the survival benefit of mechanical support in cardiogenic shock contested, with questions of patient selection and timing central to the debate.

Key figures

• Holger Thiele
• Jacob Eifer Møller

Seminal works

• thiele-2012-iabp
• moller-2024-danger

Frequently asked questions

What is the difference between temporary and durable mechanical circulatory support?

Temporary devices, often inserted percutaneously, support the circulation for hours to days during an acute crisis, while durable devices are surgically implanted to provide support over months or longer.

How does a mechanical support device help a failing heart?

Depending on its design, a device adds forward blood flow, improves coronary perfusion, or reduces the resistance the heart pumps against, helping to maintain organ perfusion and unload the failing ventricle.