CIRCULATORY ASSIST DEVICES
Circulatory assist devices (CADs) decrease cardiac work and improve organ perfusion
when conventional drug therapy is no longer adequate.
CADs provide interim support in three types of situations: (1) the left, right, or both
ventricles require support while recovering from acute injury; (2) the heart requires
surgical repair (e.g., a ruptured septum), but the patient must be stabilized; and (3) the
heart has failed, and the patient is awaiting cardiac transplantation.
Intraaortic Balloon Pump
The intraaortic balloon pump (IABP) provides temporary circulatory assistance to the
compromised heart by reducing afterload (via reduction in systolic pressure) and
augmenting the aortic diastolic pressure resulting in improved coronary blood flow and
perfusion of vital organs.
The IABP consists of a sausage-shaped balloon, a pump that inflates and deflates the
balloon, control panel for synchronizing the balloon inflation to the cardiac cycle, and
IABP therapy is referred to as counterpulsation because the timing of balloon inflation is
opposite to ventricular contraction.
The IAPB assist ratio is 1:1 in the acute phase of treatment, that is, one IABP cycle of
inflation and deflation for every heartbeat.
Complications of IABP therapy may include vascular injuries such as dislodging of
plaque, aortic dissection, and compromised distal circulation.
o Thrombus and embolus formation add to the risk of circulatory compromise to the
o Mechanical complications are rare and include improper timing of balloon
inflation causing increased afterload, decreased CO, myocardial ischemia, and
increased myocardial oxygen demand.