Clinical meaning
The IABP uses counterpulsation to augment coronary perfusion and reduce left ventricular workload. The balloon inflates during diastole (increasing diastolic augmentation and coronary perfusion pressure) and deflates just before systole (reducing afterload by creating a vacuum effect that facilitates ventricular ejection). This increases myocardial oxygen supply while decreasing demand.
Diagnosis & workup
Diagnostics & workup: - Order chest X-ray to verify balloon tip position (2-3 cm distal to left subclavian) - Monitor arterial waveform for proper timing - Order hemodynamic monitoring (CO, PAWP, MAP) - Monitor peripheral pulses in catheterized leg - Order daily CBC and coagulation studies - Monitor urine output hourly
Risk factors: - Cardiogenic shock post-MI - Refractory unstable angina - Mechanical complications of MI (VSD, papillary muscle rupture) - Bridge to cardiac surgery or transplant - Post-cardiotomy low cardiac output syndrome