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The Impella Heart Pump: a Bridge to Recovery from Cardiogenic Shock

The Impella heart pump device is an important tool in the interventional cardiologist’s toolkit. Dr. Tim Issac explains the basics behind the Impella, when it’s an appropriate bridge to recovery, and how more recent clinical studies have evolved the way we treat cardiogenic shock at Premier Cardiovascular Care.



In this Article:

  • What is cardiogenic shock

  • How the Impella heart pump works and when it’s an appropriate bridge to recovery

  • Advantages of the Impella heart pump

  • What we’ve learned from recent clinical studies


Heart Attacks and Cardiogenic Shock


If you’ve watched much television in the past couple decades, you’ve likely seen a portrayal of a myocardial infarction, usually called a heart attack. The character will stop suddenly, put a hand to his or her chest, and fall into a seat or onto the floor. You may see paramedics rush to the scene. You may see someone perform CPR, or if the situation is appropriately dramatic, maybe even an electrical shock by an external defibrillator. Then the screen will fade to black, and the next scene is in the hospital, and that same character will be awake and surrounded by family. What television fails to show is what happens between the heart attack and recovery, so we’re here to help shed some light on that part.

First, it’s important to understand a concept called cardiogenic shock.¹ “Shock” is a broad term in medicine that happens when the tissues of the body do not get enough oxygen to survive. There are many different ways this can happen, but cardiogenic shock refers to anytime shock occurs when the heart is failing to pump enough blood to the body. In a heart attack, one of the blood vessels necessary to get oxygen to the heart muscle gets obstructed, leading to damage to that heart muscle. Depending on the location or size of the damage, the heart may no longer be able to adequately pump enough blood, leading to cardiogenic shock. CPR, or cardiopulmonary resuscitation, is the most basic tool we have to help people with cardiogenic shock. And while CPR may be the best option for bystanders or first responders, hospital treatments have taken a leap forward in bridging those with cardiogenic shock to recovery.



The Impella Heart Pump: a Bridge to Recovery


Treatment for cardiogenic shock varies case by case, but the driving principle in nearly every case is to increase blood flow and improve heart function. These goals are achieved through a combination of different means, including medications to maximize heart squeeze, procedural interventions to improve heart function, and implementation of devices to help support blood flow. Often called mechanical circulatory support or a ventricular assist device (VAD),² the implementation of a VAD to help increase blood flow is often used as a bridge in the path from early treatment to long term recovery, and clinical data is increasingly showing its importance. There are generally considered four different kinds of VADs, and each was thought to have its own benefit. The one most commonly used is called an intra-aortic balloon pump, but a challenger came into the scene within the past decade called the Impella.³

The Impella devices work by generating continuous blood flow from the heart to the body through an axial pump. It comes in three versions: the Impella 2.5 provides up to 2.5 L/min of increased blood flow, the Impella CP provides up to 3.0-4.0 L/min, and the Impella 5.0 provides up to 5.0 L/min. In all versions, the device is inserted through a peripheral artery and is directed toward the heart. One end of the device is positioned in the left ventricle of the heart, while the other end extends into the aorta, the large artery of the body. Once in place, the axial pump provides constant circulatory support for the heart, minimizing any stress on the heart muscle while still generating the blood flow that the body needs.²



Advantages of the Impella Heart Pump


The Impella devices have only been around for the past decade, but there is already a substantial amount of evidence on their effectiveness. Initial studies looked at the Impella 2.5 and found that while it improved hemodynamic flow in patients, it did not confer any additional benefit compared to an intra-aortic balloon pump, while being substantially more expensive.⁴⁻⁵

However new data on the Impella CP and Impella 5.0 pumps are much more convincing. These newer studies are taking care to look at the device chosen, when it’s used, and what the outcomes are in terms of recovery of heart health or survival to definitive treatment. And when all things are considered, the data suggests that these higher flow pumps, especially the Impella 5.0, are yielding better results than any of their predecessors when used early in the treatment course.⁶⁻⁷

Finally, the Impella device is also unique for two more reasons.² The first is its low need for anticoagulation, or blood thinning. When mechanical devices are used in the blood vessels, there is often a concern for blood clots that hamper the device’s ability to work or cause additional blockages in the blood vessels. However, anticoagulation also puts patients at increased risk for bleeding, so the ability to minimize the need for anticoagulation is often beneficial. The other unique characteristic of the Impella is its capacity for use in many different situations. At the beginning of this article, we introduced you to cardiogenic shock in the setting of a heart attack, and while heart attacks are a common and concerning cause, there are several other causes of cardiogenic shock. Occasionally cardiogenic shock is due to an arrhythmia in the heart, meaning the electrical system that coordinates the heartbeat is not working properly. Because the Impella is a continuous flow pump, it doesn’t depend on cues from the heart to tell it when to work. It’s always on and always providing support.

Unlike most times in medicine, cardiogenic shock is an emergent condition that requires immediate treatment, so there won’t be time to discuss the treatment options with the doctor beforehand. However it’s important to not only understand what choices the doctor made but why they made those choices. And in the treatment of cardiogenic shock, it’s becoming increasingly clear that the Impella ventricular assist devices provide a safe and effective road to recovery for the many causes of cardiogenic shock.



About the Author


Dr. Tim T. Issac is a practicing interventional cardiologist with Premier Cardiovascular Care in the Dallas, TX metroplex. Dr. Issac has been in private practice since 2011 and specializes in minimally invasive cardiovascular interventions. You can view Dr. Issac's full bio here.


This article was written with research and editorial assistance from OnChart.


References


[1] Khalid L, Dhakam SH. A review of cardiogenic shock in acute myocardial infarction. Curr Cardiol Rev. 2008;4(1):34-40.

[2] Ergle K, Parto P, Krim SR. Percutaneous Ventricular Assist Devices: A Novel Approach in the Management of Patients With Acute Cardiogenic Shock. Ochsner J. 2016;16(3):243-9.

[3] Chera HH, Nagar M, Chang NL, et al. Overview of Impella and mechanical devices in cardiogenic shock. Expert Rev Med Devices. 2018;15(4):293-299.

[4] Mukku VK, Cai Q, Gilani S, Fujise K, Barbagelata A. Use of impella ventricular assist device in patients with severe coronary artery disease presenting with cardiac arrest. Int J Angiol. 2012;21(3):163-6.

[5] Percutaneous Ventricular Assist Devices: A Health Technology Assessment. Ont Health Technol Assess Ser. 2017;17(2):1-97.

[6] Sieweke JT, Berliner D, Tongers J, et al. Mortality in patients with cardiogenic shock treated with the Impella CP microaxial pump for isolated left ventricular failure. Eur Heart J Acute Cardiovasc Care. 2018;:2048872618757393.

[7] Batsides G, Massaro J, Cheung A, Soltesz E, Ramzy D, Anderson MB. Outcomes of Impella 5.0 in Cardiogenic Shock: A Systematic Review and Meta-analysis. Innovations (Phila). 2018;13(4):254-260.


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