Do intra-aortic balloon pumps (IABPs) decrease afterload?

From the Guidelines

Yes, intra-aortic balloon pumps (IABPs) do decrease afterload. The mechanism by which IABPs decrease afterload is through counterpulsation, where the balloon inflates during diastole and deflates just before systole, creating a temporary reduction in aortic pressure 1. This reduction in afterload decreases myocardial oxygen demand and workload on the failing heart.

Key Points

• IABPs work by inflating a 30–50-mL balloon placed in the thoracic aorta through the femoral artery, which increases aortic diastolic pressure and coronary flow during inflation, and decreases after-load during deflation 1.
• The use of IABPs is recommended for patients with cardiogenic shock or severe acute left heart failure that does not respond to other treatments, and may be corrected with coronary revascularization, valve replacement, or heart transplant 1.
• IABPs are contraindicated in patients with aortic dissection or significant aortic insufficiency, and should not be used in patients with severe peripheral vascular disease, uncorrectable causes of heart failure, or multi-organ failure 1.

Clinical Considerations

• The afterload reduction effect of IABPs is one of three primary hemodynamic benefits, alongside increased coronary perfusion during diastolic inflation and improved cardiac output.
• Patients with IABPs typically require anticoagulation with heparin to prevent thromboembolic complications.
• The class of recommendation for IABC is I, with a level of evidence B 1.

From the Research

Intra-Aortic Balloon Pumps and Afterload

• Intra-aortic balloon pumps (IABPs) are used to support severely compromised ventricles in critically ill patients 2.
• The device acts by external counterpulsation and uses systolic unloading and diastolic augmentation of aortic pressure to improve hemodynamics 3.
• IABPs enhance myocardial function by maximizing oxygen supply and minimizing oxygen demand, which can lead to a decrease in afterload 4.
• The use of IABPs can increase cardiac output and reduce work on the left ventricle through diastolic augmentation and counterpulsation, thereby decreasing afterload 5.

Mechanism of Action

• The intra-aortic balloon pump works by inflating a balloon in the aorta during diastole, which increases aortic pressure and enhances coronary perfusion 3.
• During systole, the balloon deflates, which decreases aortic pressure and reduces afterload, allowing the left ventricle to pump more efficiently 4.
• This mechanism of action suggests that IABPs can decrease afterload, although the clinical significance of this effect may vary depending on the patient population and underlying condition 2.

Clinical Evidence

• Studies have shown that IABP use is associated with increased cardiac output and reduced mortality in certain patient populations, although the evidence is not uniform 6.
• The IABP-SHOCK-II trial found no survival benefit with IABP use in patients with cardiogenic shock, although subgroup analysis suggested potential benefits in certain patient populations 6.
• Overall, the available evidence suggests that IABPs can decrease afterload, although the clinical implications of this effect require further study 3, 4, 5, 2, 6.