SCCM Resource Library-Intra-Aortic Balloon Pump

Video Transcription

It is a pleasure to present at the 51st virtual SCCM Congress. I'm here to discuss interuric balloon pumps for the session that's mechanical circulatory  support for cardiogenic shock, past, present, and future.  My name is Sami Zakaria. I'm an associate professor of medicine at Johns Hopkins University School of Medicine,  and I currently serve as the director of the Cardiac Intensive Care Unit at Johns Hopkins Bayview Medical Center. Inter-aortic balloon pumps have been around for a very long time.  Dr. Adrian Kantrowicz, who was also famous for performing the first human heart transplant in the United States three days after the first attempt in South Africa, first conceived  of this idea in the 1950s and 1960s. His vision was that you would implant a balloon in the descending aorta, which would inflate  during diastole, thereby increasing diastolic blood pressure and blood delivery to the heart and the coronary arteries.  But during systole, the balloon would deflate, which would decrease left ventricular afterload and make it easier for the heart to pump blood into the aorta.  He finally had a working model in 1968 and implanted it in two human patients. Both had improvements in hemodynamics, and actually one patient survived hospitalization.  Since then, there have been improvements in the design of the inter-aortic balloon pump. It has become thinner and subsequently was able to be inserted percutaneously starting  in the early 1980s. It has been a common tool used by interventional cardiologists and now is the most popular form of temporary mechanical circulatory support devices.  The graphic on the left just is a reminder of how an inter-aortic balloon pump works. During diastole, the balloon inflates, and it increases diastolic blood pressure into  the great arteries and also into the coronary arteries, increasing blood flow to the heart and delivering more oxygen.  During systole, the balloon deflates, which decreases LV afterload and allows for blood to exit from the left ventricle into the aorta.  The net effect of this can be seen in this graphic on the right during fluoroscopy, where you see a balloon being inflating and deflating in time with cardiac contraction.  Dynamically, the inter-aortic balloon pump has a number of effects. To the left side of the screen, you'll see aortic tracing during unassisted systole and diastole.  In other words, the balloon pump isn't working. You'll see unassisted systole around 110 here, then the blood pressure decreases, and then  you'll have the dicrotic notch is when the aortic valve closes, and then blood pressure in the aorta decreases until you reach end diastolic pressure in the aorta.  Then the left ventricle contracts again, the aortic valve opens, and then you have a rapid increase in aortic blood pressure until you reach unassisted systole peak again.  However, this time, what you see is the inter-aortic balloon pump blows up at the dicrotic notch,  which increases diastolic aortic root and coronary artery pressures, which increases blood flow and oxygen into the heart.  The balloon then deflates, and then you'll see assisted systole being the second portion of it. And notice that it's lower pressure than unassisted systole.  The net effect of this is a decline in afterload, which decreases cardiac work and stress. These changes in aortic hemodynamics lead to a net increase in cardiac output by 0.5  to 1 liters, which is about a 20% increase in cardiac output. And this can make a big difference in patients in shock. There are a lot of indications for inter-aortic balloon pumps.  Probably the best evidence-based indication is for patients who have cardiogenic shock secondary to acute myocardial infarction.  In these patients, 75% of them will have improvements in hemodynamics after you put in a balloon pump.  It could be used for other indications as well, including post-cardiotomy shock or refractory stage D heart failure patients.  That being said, in recent years, the inter-aortic balloon pump has started to fall out of favor, although it remains heavily used. And evidence is mixed on its benefits.  There was an old trial published in the late 90s and early 2000s called the IABP shock trial, which had routine use of inter-aortic balloon pumps.  And that was associated with a mortality benefit that continued to six years. A more recent trial published in 2012 called the IABP shock two trial showed no benefit  for the routine use in acute myocardial infarction patients who had associated cardiogenic shock.  There were many thoughts why there's no benefit in a newer trial. One is that more of these patients underwent emergent percutaneous coronary intervention.  Another reason is that balloon pumps were often placed after the intervention in 85% of patients, not before, when it may be more helpful.  The third comment is that there was frequent crossover and higher use of percutaneous ventricular assist devices in the control group.  Nonetheless, despite these criticisms, it's pretty clear that there's really no benefit with the routine use of inter-aortic balloon pumps in acute MI patients.  And it really should be reserved for a select group of patients and based on clinical judgment.  For chronic heart failure, there really are no trials looking at its use in patients who need LVAD as a transplant. In historical times, it was used more from a femoral approach.  And the problem with that is that the patients were unable to rehab because they couldn't walk.  And there are other devices, such as an EVAD, which is far preferable in these patients. Nowadays, many more balloon pumps are being placed from an axillary approach, which allows  for ambulation and allows for rehabilitation. This could be especially helpful for patients who are awaiting heart transplant, where it's  very important to have some type of mechanical circulatory support device to bridge them to transplant.  Balloon pumps have been compared to other temporary mechanical circulatory support devices, including the Impella device or the TandemHeart.  Both of these were reviewed in a paper published in CurriculCare Medicine in 2017. Notice that all were small trials.  In fact, the largest trial only included 48 patients, and the smallest one included 21.  But for what it's worth, there was no difference in outcomes in patients who were treated with  balloon pump therapy versus those who were treated with other types of percutaneous mechanical circulatory support devices. A later study reported similar results.  In this trial, it compared patients with a balloon pump versus an Impella device. And again, there was no difference in outcomes.  That being said, there was one paper that was published in JAMA in 2020 that showed a benefit to balloon pump placement compared to an intervascular microaxial left ventricular  assist device. The brand name would be Impella. This was based on a propensity-matched registry study, and it showed that there was benefits  to the balloon pump compared to the other type of device. In any case, if you decide to use a balloon pump, it's important that you place it early.  Look at this study that was published in the American Journal of Cardiology in 2019. Patients who had a balloon pump in less than one hour after presentation had a much higher  survival rate compared to those who had balloon pumps placed in later. So in summary, I have a few real-world indications where you could consider using a balloon pump  in patients who are in shock. Based on the IAVP SHOCK 2 trial, I'm pretty convinced that you don't need to routinely  place a balloon pump in patients who are in cardiogenic shock that are improving after percutaneous coronary intervention or who are stabilized with other therapies.  However, it's extremely useful for crashing cardiogenic shock patients, and it could quickly stabilize patients, and it could be inserted percutaneously in a few minutes.  Most of the time, these devices are inserted in the cardiac cath lab where they have fluoroscopic guidance, or you can insert it blindly at the bedside with no guidance at all.  You could also consider inserting it with TE guidance. Here to the top right of the screen, you'll see a picture of the descending aorta, and  you can see a balloon pump being inserted in real time. In the bottom right, you'll see a graphic where the balloon pump is inflating and deflating in time with the cardiac cycle.  So the bottom line is that this device could be quickly inserted using direct visualization or without it.  A balloon pump is also extremely valuable as a bridge to another procedure. You could quickly insert a balloon pump, and then it buys you time to consider placing  a more comprehensive MCS device that could have a greater cardiac output or might buy you enough time to place a permanent ventricular assist device or even to cardiac transplant.  Finally, a balloon pump is useful as a bridge to recovery. In other words, a patient might need a balloon pump for a few hours, two days, and then gets  removed as the patient gets better. It's also useful for another situation such as high-risk PCI or electrophysiology procedures  such as VT ablations, but that's less often used in the real world. And most practitioners, they're now turning to microaxial percutaneous ventricular assist devices.  Here are my contraindications for using a balloon pump in the real world. Number one, because a balloon pump inflates during diastole, it will push more blood into  the left ventricle if there's significant aortic regurgitation. So it is contraindicated in patients with aortic regurgitation or in those with AV shunting  because it'll also push more blood into the venous side. It's also not useful in patients who have an aortic aneurysm or aortic dissection because it could cause further damage.  It's not too useful for sepsis since it's associated with infection. It's not good for bleeding disorders because it could shred platelets and red blood cells.  And it's not useful in patients with bilateral peripheral vascular disease or grafts, and that's because it's just too hard to place the device.  A balloon pump is also associated with significant complications. Because you're putting a big catheter inside the femoral artery, it could occlude blood flow into the distal leg.  And 8% to 10% of patients will have leg ischemia. And some of them, 3% to 5%, will have clinically significant thrombosis or cholesterol embolization.  Because it could damage red blood cells and platelets, it's also associated with bleeding, both at the insertion site and elsewhere.  And so these patients have to be watched for thrombocytopenia or hemolysis. Finally, there could be obstruction of arterial flow due to malposition.  If the balloon pump is too low, it might occlude the renal arteries. Or if it's too high, it might occlude the great arteries.  To be honest, I have never seen this, and I don't know how much clinically relevant it is. But it is something to be aware of.  Less common complications from a balloon pump include stroke because it could damage a plaque or dislodge a plaque that's on the aorta and embolize it to the brain.  Because it's a device, it could be associated with sepsis or other types of infections. And there could be other problems like balloon leaks or ruptures or peripheral neuropathy.  So you have to keep these in mind when you decide to insert a balloon pump. But in summary, I wanted to thank you for listening to this virtual presentation.  My email address is on the top right hand of this slide in case you have any further questions.  But I believe that the balloon pump has a useful role in patients with cardiogenic shock. And the following presentations will also tell you the roles for other temporary mechanical  circulatory support devices. Thank you, and have a great day.

Video Summary

The speaker discusses inter-aortic balloon pumps as a form of mechanical circulatory support for cardiogenic shock. The history, design, and functionality of the pumps are explained, as well as their impact on aortic hemodynamics and cardiac output. The effectiveness and indications for use are discussed, with a focus on patients with cardiogenic shock secondary to acute myocardial infarction. The speaker also mentions the mixed evidence on the benefits of inter-aortic balloon pumps, highlighting the need for clinical judgment in their use. The presentation concludes with contraindications and potential complications of using balloon pumps.

Asset Subtitle

Cardiovascular, Shock Non Sepsis, 2022

Asset Caption

Cardiogenic shock after acute myocardial infarction requires immediate resuscitative therapy to prevent irreversible organ damage. Mortality, although decreased significantly, remains high. Intensivists more frequently encounter patients with cardiogenic shock. The key to a good outcome is an organized approach, with rapid recognition and prompt initiation of therapy to improve hemodynamics, tissue perfusion, ventilatory support, and reversal of the underlying cause. The concept of establishing ventricular support before revascularization stresses the notion that unloading the left ventricle is key to its recovery. Different percutaneous devices for mechanical support have different effects on left ventricular afterload and myocardial oxygen demand. An understanding of the advantages and disadvantages of these devices helps the clinician select the right device in the right setting.

Meta Tag

Content Type Presentation

Knowledge Area Cardiovascular

Knowledge Area Shock Non Sepsis

Knowledge Level Intermediate

Knowledge Level Advanced

Learning Pathway Cardiothoracic Critical Care

Membership Level Select

Tag Hemodynamic Monitoring

Tag Cardiovascular

Tag Cardiothoracic Critical Care

Year 2022

Keywords

inter-aortic balloon pumps

mechanical circulatory support

cardiogenic shock

aortic hemodynamics

cardiac output

	Society of Critical Care Medicine 500 Midway Drive Mount Prospect, IL 60056 USA Phone: +1 847 827-6888 Fax: +1 847 439-7226 Email: support@sccm.org	Contact Us About SCCM Newsroom Advertising & Sponsorship DONATE	MySCCM LearnICU Patients & Families Surviving Sepsis Campaign Critical Care Societies Collaborative	GET OUR NEWSLETTER
© Society of Critical Care Medicine. All rights reserved. \| Privacy Statement \| Terms & Conditions The Society of Critical Care Medicine, SCCM, and Critical Care Congress are registered trademarks of the Society of Critical Care Medicine.