An intraaortic balloon pump (IABP) is a device that increases blood flow to the heart muscle and decreases the heart’s workload through a process called counterpulsation.

In the early 1950s, researchers discovered that the heart is doing two different kinds of work. The first type of work occurs during the pumping part of the heartbeat (the systole), during which the heart must overcome the blood pressure in the aorta in order to pump blood through it. The second type of work occurs during the relaxed part of the heartbeat (the diastole), during which the heart receives blood via backflow from the aorta. This is described as the difference between pressure work and flow work, respectively. The flow of blood to the heart muscle through the coronary arteries mainly occurs during the diastole.  A healthy heart is normally able to accomplish both types of work effectively, but a weakened heart will have more difficulty.

Counterpulsation was introduced as a strategy by which the blood flow to the heart muscle could be increased during diastole (less flow work). The increased blood flow provides the heart with more oxygen, which improves circulation, cardiac output and the heart rate. As a result, the technique relieves, for example, the pain and discomfort from angina.

The IABP device contains a small balloon that is inflated inside the aorta when the heart muscle relaxed, increasing pressure inside the heart chambers and increasing blood flow to the coronary arteries. Then the balloon is deflated just before the heart muscle pumps, creating a vacuum effect that aids blood flow from the heart, thus reducing systolic blood pressure and increasing the heart’s ability to pump blood. In this way, the device improves blood flow to the heart muscle and reduces the workload of the heart muscle. 

The IABP has been modified and improved upon numerous times since its introduction in 1967, including its adaptation to catheters. Today, IABPs are inserted using catheters. The gas used to inflate the balloon is either carbon dioxide (which has fewer consequences in the rare event of a balloon bursting) or helium (which has the fastest ability to travel or diffuse).

With more than 70,000 IABP procedures performed every year, it is the most commonly used circulatory assist device in the United States. For instance, the IABP is used to help wean high-risk patients off the heart-lung machine after bypass surgery. It also is used in the early support and stabilization of high-risk patients undergoing angiography and angioplasty.

Other uses include:

• Treating patients with shock due to left ventricular failure or heart attack
  
• Treatment of intractable angina
  
• Among patients with severe coronary artery disease who are waiting for surgery

Because it is placed in the aorta, patients with aorta-related problems (e.g., aortic dissection, aortic regurgitation) are not generally eligible for this treatment.