Intra-aortic balloon pump (IABP) 

The intra-aortic balloon pump (IABP) is a mechanical device that provides circulatory assistance to patients with serious cardiac impairment awaiting heart transplant. An IABP is primarily a mechanical circulatory support device used as a bridge to heart transplant in patients with severe cardiac failure.

What is an Intra-Aortic Balloon Pump (IABP)?

An IABP is a catheter with a balloon at its end that is inserted into the aorta to assist the heart in pumping blood. It is usually placed in the aorta below the celiac artery. An IABP is typically inserted into the femoral artery (or, more rarely, the subclavian artery) and guided into the aorta.

How IABP Works

Balloon Inflation

The balloon of the IABP is inflated at the beginning of diastole and increases blood flow and coronary artery perfusion.

Balloon Deflation

The balloon of the IABP is deflated just before systole to reduce the afterload and, thus, decrease the oxygen demand of the heart.

Assisting Cardiac Output

This assistance to the heart allows maintaining the cardiac output in patients with significantly reduced cardiac function.

IABP as a Bridge to Heart Transplant (Indications)

IABP is indicated in patients who require temporary circulatory assistance for bridging until a donor heart becomes available. Thus, IABP can be used in patients with cardiogenic shock or acute decompensation of chronic heart failure. The following diseases/conditions are the major indications for IABP as a bridge to heart transplant:

Cardiogenic Shock

Cardiogenic shock is a syndrome that involves decreased cardiac output and tissue perfusion, which leads to dysfunction of other organs. This condition can be caused by cardiomyopathy, valvular or congenital heart disease, among other causes. An IABP can be used to increase coronary artery perfusion and help the heart pump blood.

Acute Decompensated Heart Failure

Acute decompensation of chronic heart failure is a clinical manifestation of chronic heart failure deterioration. It can be caused by various factors, including fluid accumulation, arrhythmia, or disease progression. An IABP can be used as a bridge to heart transplant to temporarily reduce the afterload and increase the cardiac output in patients with acute decompensated heart failure.

Severe Left Ventricular Dysfunction

Left ventricular dysfunction is a condition characterized by the reduced ability of the left ventricle to pump blood. It can be caused by coronary artery disease, myocarditis, cardiomyopathy, or other conditions. An IABP can be used to increase coronary artery perfusion, reduce afterload, and improve the cardiac output.

Post-Surgical Heart Failure

This type of heart failure develops as a complication following a surgical intervention, for example, coronary artery bypass grafting or heart valve surgery. An IABP can be used to provide temporary circulatory assistance to the heart.

Post-Myocardial Infarction (Heart Attack)

This condition is characterized by the development of heart failure following a severe heart attack that inflicts significant damage to the mycardium. An IABP can be used to assist the heart in pumping blood and increasing coronary blood flow until a heart transplant is available.

End-Stage Heart Failure

End-stage heart failure is severe heart failure that generally requires a heart transplant to recover. An IABP can be used as a bridge to heart transplant in patients with end-stage heart failure.

How IABP Works as a Bridge to Heart Transplant

An IABP can be used as a bridge to heart transplant to provide temporary circulatory assistance to patients with severe cardiac dysfunction. The mechanisms by which an IABP works as a bridge to heart transplant include:

Improving Coronary Blood Flow

As described above, an IABP increases coronary blood flow by inflating the balloon at the beginning of diastole. This mechanism is especially beneficial for patients with coronary artery disease because it improves the perfusion of the heart muscle.

Reducing Afterload on the Heart

An IABP decreases the afterload by deflating the balloon just before the beginning of systole. This reduces the pressure in the aorta, which decreases the resistance in the systemic circulation. This, in turn, decreases the workload of the heart.

Improving Organ Perfusion

The increased cardiac output due to reduced afterload and improved coronary perfusion helps increase the perfusion of other organs and tissues, such as the brain and kidneys. This prevents their dysfunction that can be caused by inadequate blood supply.

Stabilizing the Patient

An IABP can temporally stabilize the patient with severe cardiac dysfunction to allow for a heart transplant.

Bridge to Recovery or Transplant

Although the primary indication for an IABP as a bridge to heart transplant is to allow the patient to survive until a donor heart is available, this mechanical support can facilitate partial recovery of the heart function. During this period, the patient is taken off the IABP and placed on other types of circulatory support, including heart transplant.

Procedure for IABP Insertion

An IABP is inserted through a minimally invasive procedure in a catheterization lab or an operating room. The procedure involves the following major steps:

Access Site

The first step in inserting an IABP is to gain access to the femoral artery (or, rarely, the subclavian artery). The area of insertion is numbed by local anaesthetic. Moreover, the patient may be given sedative medication to help them relax.

Insertion

A catheter with a balloon at its end is then guided into the aorta and placed below the celiac artery. When the catheter is placed at the desired position, the balloon is connected to a pressure pump.

Balloon Inflation and Deflation

The pressure pump causes the balloon to inflate and deflate at specific times during the cardiac cycle. The timing of the balloon inflation and deflation is coordinated with the heartbeat of the patient. In particular, the balloon is inflated at the beginning of diastole and deflated just before the start of systole.

Monitoring

Then, the functioning of the IABP is monitored to ensure that it is appropriate. The functioning of the heart is also assessed. If everything is okay, the patient is sent to the intensive care unit.

Duration of Use

The IABP is typically left in place for a short period of time until a donor heart becomes available. Then, it is removed, and the patient is subjected to heart transplant surgery.

Benefits of IABP as a Bridge to Heart Transplant

The major benefits of using an IABP as a bridge to heart transplant are listed below:

Providing Temporary Hemodynamic Support

An IABP can provide temporary hemodynamic support to patients with severe cardiac dysfunction.

Improving Myocardial Perfusion

An IABP increases coronary artery perfusion, which improves myocardial perfusion.

Reducing Myocardial Oxygen Demand

An IABP decreases the afterload and, thus, decreases the oxygen demand of the heart.

Protecting Vital Organs

An IABP can protect vital organs, such as the brain, kidneys, and liver, from hypoperfusion-related damage.

Minimally Invasive

An IABP is inserted using a minimally invasive procedure. Moreover, an IABP generally has fewer complications compared to other mechanical circulatory support devices, such as extra-corporeal membrane oxygenation (ECMO).

Improving Survival Rates in Patients with Cardiogenic Shock

Studies have shown that an IABP can improve survival rates in patients with cardiogenic shock.

Risks and Complications of IABP Use

An IABP is generally safe, but it is also associated with several risks and potential complications, including:

Vascular Injury

The insertion of an IABP can lead to several vascular injuries, including bleeding at the site of catheterization, formation of a hematoma, and dissection of the artery.

Infection

An infection can develop at the site of IABP insertion. Moreover, a rare but serious infection can occur in deeper tissues.

Thrombosis

An IABP can cause the formation of blood clots. This complication generally occurs in the arteries and can lead to impaired blood flow and tissue ischemia.

Hemolysis

An IABP can cause the rupture of erythrocytes, leading to hemolysis.

Kidney Injury

Reduced perfusion of the kidneys can cause acute kidney injury.

Device Malfunction

The IABP can malfunction; however, this is a rare complication.

Post-IABP and Heart Transplant Surgery

Following the removal of an IABP, the patient generally undergoes post-transplant recovery. Moreover, the patient is generally monitored in a recovery unit to detect and manage possible transplant-related complications. The patient may also be given immunosuppressive therapy to prevent transplant rejection.

Overall, an IABP is a very beneficial device for patients with severe cardiac dysfunction awaiting heart transplant.