What are the indications and mechanism of an Intra-Aortic Balloon Pump (IABP)?

Intra-Aortic Balloon Pump (IABP): Indications and Mechanism

Mechanism of Action

The IABP improves diastolic coronary and systemic blood flow while simultaneously reducing afterload and myocardial work through counterpulsation. 1

The device operates through the following physiological principles:

• Inflates during diastole to augment diastolic arterial pressure, thereby increasing coronary perfusion and systemic blood flow 1, 2
• Deflates during systole to decrease systolic pressure and reduce left ventricular afterload 2
• Decreases myocardial oxygen consumption while modestly improving cardiac output, favorably modifying the oxygen demand/supply balance 3
• Modern IABPs use aorta flow detection for triggering, overcoming previous limitations in patients with atrial fibrillation and other arrhythmias 3

Current Evidence-Based Indications

Strongly Supported Indications

IABP is recommended for mechanical complications of acute myocardial infarction, including interventricular septal rupture, acute mitral regurgitation from papillary muscle rupture, and free wall rupture with tamponade. 3, 4

• Severe acute myocarditis requiring hemodynamic support 3, 4
• Bridge therapy for patients awaiting ventricular assist device implantation or heart transplantation 4
• Postcardiotomy cardiac dysfunction, especially with suspected coronary hypoperfusion 3
• Selected patients with acute myocardial ischemia/infarction before, during, and after revascularization who are at high risk for complications 3, 4

NOT Routinely Recommended

IABP is NOT recommended for routine use in cardiogenic shock complicating acute myocardial infarction without mechanical complications, as recent evidence shows no 30-day survival benefit and higher rates of stroke and bleeding. 3, 4

• Randomized trials in STEMI showed neither survival benefit nor improved left ventricular ejection fraction, while being associated with significantly higher stroke and bleeding rates 1
• In STEMI patients with cardiogenic shock treated with primary PCI, IABP was associated with a 6% increase in 30-day mortality 1
• The only potential benefit was seen in patients treated with thrombolysis (18% decrease in mortality), though this data is hampered by bias and confounding 1

Contraindications

IABP is contraindicated in patients with severe aortic insufficiency and advanced peripheral or aortic vascular disease. 3

Additional contraindications include:

• Aortic dissection or aneurysm 2
• Severe peripheral vascular disease 2

Clinical Decision Algorithm

When considering IABP, follow this approach:

1. First, identify if mechanical complications are present (septal rupture, acute MR, free wall rupture) → Insert IABP immediately and arrange emergent surgical consultation 3, 4

2. For severe acute myocarditis with hemodynamic compromise → Consider IABP for temporary support 3, 4

3. For cardiogenic shock from LV failure alone (no mechanical complications) → Do NOT routinely use IABP; consider alternative mechanical support devices like Impella or VA-ECMO instead 3, 4

4. For high-risk PCI or CABG → Consider prophylactic IABP in highly selected cases, though evidence is limited 5, 6

5. As bridge to durable therapy → IABP may be used while awaiting VAD or transplant 4

Important Clinical Pitfalls

• Do not delay surgery when mechanical complications are present; IABP is only a bridge to definitive surgical repair, not definitive therapy 3
• Do not use IABP routinely in cardiogenic shock without mechanical complications, as this increases complications without improving mortality 3, 4
• Monitor for complications including bleeding, systemic thromboembolism, limb ischemia, and rarely death 2
• Ensure adequate anticoagulation to prevent pump thrombosis while balancing bleeding risk 3

Alternative Mechanical Support Options

For patients with severe or refractory cardiogenic shock where IABP is not indicated:

• Microaxial intravascular flow pumps (Impella) may be reasonable to reduce mortality in selected STEMI patients 3
• Ventricular assist devices should be considered early for more severe heart failure 3
• VA-ECMO may serve as a bridge to recovery or decision-making, though not recommended routinely due to lack of survival benefit 3