Intraaortic balloon counterpulsation and microcirculation in cardiogenic shock complicating myocardial infarction: an IABP-SHOCK II substudy.

OBJECTIVES: This study sought to evaluate the influence of intraaortic balloon pump (IABP) counterpulsation on the microcirculation in patients with cardiogenic shock (CS) complicating acute myocardial infarction.

BACKGROUND: In patients with shock profound alterations of the microcirculation have been observed and their clinical relevance has been described. Different treatment strategies exist to improve microvascular perfusion in patients with CS; however, the role of IABP treatment is not clearly defined.

METHODS: A predefined substudy of the randomized Intraaortic Balloon Pump in Cardiogenic Shock II trial (IABP-SHOCK II) investigated the sublingual microcirculation using a sidestream darkfield intravital microscope on days 1, 2 and 4 after the onset of shock. Perfused capillary (<20 µm, PCD) and vessel densities (<100 µm, PVD), total capillary (TCD) and vessel (TVD) densities were determined. In addition, the proportion of perfused vessels was assessed.

RESULTS: Forty-one patients were included in this substudy (n = 24 with IABP support vs. n = 17 without IABP support). No significant differences between treatment with or without IABP regarding PCD, PVD, TCD, TVD and the proportion of perfused vessels were evident on all three timepoints (p = n.s. for all). Microvascular perfusion showed inverse correlation with subsequent serum lactate levels (-0.366; p = 0.02) without being significantly correlated with lactate levels at the timepoint of the microcirculatory investigation. In Kaplan-Meier analysis microcirculatory parameters showed significant discrimination of prediction for time to death (p < 0.05 for all).

CONCLUSIONS: In patients with CS, there is no effect of IABP treatment on microvascular perfusion. Parameters of the microcirculation might be helpful to identify high risk patients.