Intraaortic balloon pumping: why should we hurry up?

Introduction

Application of the intraaortic balloon pump (IABP) for patients with acute myocardial infarction complicated by cardiogenic shock is undoubted. But the time of IABC initiation is questionable. The goal of the study was to evaluate the influence of the IABP initiation time and dose of dopamine for patient hemodynamic data and inhospital mortality.

Methods

Sixty-two consecutive acute myocardial infarction patients managed with IABP were included in the study. The initiation time of IABP and administered dopamine doses were compared. Two subgroups of patients were separated: those receiving less than 10 μg/kg/minute dopamine, and others receiving 10 μg/kg/minute dopamine or more. Standard hemodynamic indices of cardiac output (CO), cardiac index (CI), stroke volume (SV), stroke index (SI), pulmonary capillary wedge pressure (PCWP), mean pulmonary artery pressure (PAmean), cardiac power (CP = CO × MAP/451, where MAP is mean arterial pressure) and cardiac power index (CPI = CI × MAP/451) were measured.

Results

CO in the first group was 3.58 ± 1.12 l/minute, in comparison with 2.54 ± 1.08 l/minute (P < 0.0001) in the second group. CI correspondingly was 1.9 ± 0.6 l/minute/m² and 1.38 ± 0.61 l/minute/m² (P = 0.001), SV was 43.8 ± 26.14 ml and 30.01 ± 13.75 ml (P = 0.012), SI was 23.93 ± 15.58 ml/m²and 16.28 ± 7.75 ml/m² (P = 0.017), CP was 0.68 ± 0.25 W and 0.4 ± 0.23 W (P < 0.0001), CPI was 0.36 ± 0.14 W/m² and 0.22 ± 0.13 W/m² (P < 0.0001), PCWP was 21.32 ± 6.04 mmHg and 24.16 ± 7.42 mmHg (P = 0,104), PAmean was 28.74 ± 8.53 mmHg and 30.23 ± 7.05 mmHg (P = 0.47). In the second subgroup, hemodynamic indices (CO, CI, SV, SI, CP and CPI) were statistically significantly lower (P < 0.05) in comparison with the data of patients receiving less than 10 μg/kg/minute, while PCWP and CVP values differed insignificantly. Inhospital mortality was higher among patients receiving 10 μg/kg/minute dopamine or more. Among 31 patients receiving less than 10 μg/kg/minute dopamine 16 (51.6%) died, while among those 31 receiving 10 μg/kg/minute or more 27 (87.1%) died. This was a significant difference according to the Pearson χ² criterion (χ² = 9.182, P = 0.002).

Conclusion

Initiation of aortic counterpulsation should be considered as soon as possible, while the patient with acute myocardial infarction is treated with low doses of vasopressors.