Interventional physiology. Part XVIII: Influence of intra-aortic balloon counterpulsation and collateral flow reversal during multivessel angioplasty

Effects of intraaortic balloon counterpulsation on translesional coronary hemodynamics

The intraaortic balloon pump (IABP) provides counterpulsation by displacing a 40-50 cc blood volume during diastole augmenting diastolic pressure. The rapid deflation of the balloon timed to the initiation of systole reduces the afterload of ventricular ejection and thus peak systolic pressure. As a direct result, IABP increases mean arterial pressure (MAP) and peak diastolic pressure while reducing systolic pressure and myocardial work. IABP increases coronary flow velocity in non-obstructed vessels, but does not increase flow across a severe obstruction as shown by intracoronary Doppler flow studies (Kern et al., Circulation, 1993;87:500-511 and Kern et al., Circulation 1991;84:II-485). There are few studies using pressure sensor guidewires to confirm these responses. We present a case illustrating the translesional hemodynamics using an angioplasty sensor pressure wire across a severe stenosis and the unique influence of the IABP.

Role of prophylactic intra-aortic balloon pump in high-risk patients undergoing percutaneous coronary intervention

Intra-aortic balloon pump (IABP) has been shown to support patients who are at high risk for percutaneous coronary interventions (PCIs) or becoming hemodynamically unstable during PCI, but the longer term outcomes of these strategies are unknown. This study investigated the outcomes of high-risk patients who received a prophylactic IABP (P-IABP) versus patients who required rescue IABP (R-IABP) because of intraprocedural complications. Clinical outcomes of 68 consecutive patients (69 procedures) who underwent high-risk PCI with P-IABP support were compared with those of 46 patients who required R-IABP. Patients who presented with cardiogenic shock or acute ST-segment elevation myocardial infarction, and those who were on mechanical ventilators were excluded. Clinical baseline characteristics were similar between groups except for more diabetics and patients with hypercholesterolemia in the P-IABP group. The procedural success was higher in the P-IABP group, with lower in-hospital mortality and major complications, than in the R-IABP group. At 6 months, the mortality and major adverse cardiac event rates were lower in the P-IABP group (8% vs 29%, p < 0.01, and 12% vs 32%, p = 0.02, respectively). Multivariate analysis showed that prophylactic insertion of an IABP is the only independent predictor of survival at 6 months. The incidence of vascular complications was low and comparable except for more major bleeding (15% vs 3%, p = 0.03) in the R-IABP group. In conclusion, patients who undergo high-risk PCI and then receive P-IABP support have favorable outcomes compared with those who require R-IABP for intraprocedural complications. Therefore, in high-risk patients undergoing PCI, liberal use of a P-IABP should be considered.