Intraaortic Balloon Pumping for Ventricular Septal Defect or Mitral Regurgitation Complicating Acute Myocardial Infarction

Abstract

The intraaortic balloon pump (IABP) has been employed in the management of five patients with ventricular septal rupture (VSD) and six patients with acute mitral regurgitation (AMR) following myocardial infarction. All patients were in cardiogenic shock which responded poorly to medical therapy including pressor and inotropic agents. IABP resulted in significant clinical and hemodynamic improvement in all cases. In patients with VSD, IABP produced a fall in wedge (PCW) pressure from 17 ± 4 (sd) to 13 ± 4 mm Hg (P < 0.01) while mean arterial pressure increased from 68 to 73 mm Hg. Systemic A-V O₂ difference fell from 9.7 ± 2.4 to 8.1 ± 2.4 vol % (P < 0.05) while pulmonary A-V O₂ difference was unchanged. Thus the pulmonic/systemic flow ratio (P/S) declined in all patients. In patients with AMR, PCW fell from 25 ± 4 to 20 ± 4 mm Hg (P < 0.02) with a significant diminution in "V"-wave amplitude. Cardiac output (CO) rose from 3.1 ± 0.9 to 3.7 ± 1.0 liters/min (P < 0.01). All patients underwent coronary angiography without complication in preparation for emergency surgery. IABP reduces AMR following acute myocardial infarction and reduces the P/S in VSD by a selective augmentation of systemic CO. Such direct therapy acutely stabilizes these severely ill patients. Detailed angiography may then be performed safely.