title: Withdrawing intra-aortic balloon pump support paradoxically improves microvascular flow.
abstract: BACKGROUND
  The Intra-Aortic Balloon Pump (IABP) is frequently used to mechanically support the heart. There is evidence that IABP improves microvascular flow during cardiogenic shock but its influence on the human microcirculation in patients deemed ready for discontinuing IABP support has not yet been studied. Therefore we used sidestream dark field imaging (SDF) to test our hypothesis that human microcirculation remains unaltered with or without IABP support in patients clinically ready for discontinuation of mechanical support.
  
  
  METHODS
  We studied 15 ICU patients on IABP therapy. Measurements were performed after the clinical decision was made to remove the balloon catheter. We recorded global hemodynamic parameters and performed venous oximetry during maximal IABP support (1:1) and 10 minutes after temporarily stopping the IABP therapy. At both time points, we also recorded video clips of the sublingual microcirculation. From these we determined indices of microvascular perfusion including perfused vessel density (PVD) and microvascular flow index (MFI).
  
  
  RESULTS
  Ceasing IABP support lowered mean arterial pressure (74 ± 8 to 71 ± 10 mmHg; P = 0.048) and increased diastolic pressure (43 ± 10 to 53 ± 9 mmHg; P = 0.0002). However, at the level of the microcirculation we found an increase of PVD of small vessels <20 μm (5.47 ± 1.76 to 6.63 ± 1.90; P = 0.0039). PVD for vessels >20 μm and MFI for both small and large vessels were unaltered. During the procedure global oxygenation parameters (ScvO2/SvO2) remained unchanged.
  
  
  CONCLUSIONS
  In patients deemed ready for discontinuing IABP support according to current practice, SDF imaging showed an increase of microcirculatory flow of small vessels after ceasing IABP therapy. This observation may indicate that IABP impairs microvascular perfusion in recovered patients, although this warrants confirmation.
authors.affiliation: Department of Translational Physiology, Academic Medical Center, University of Amsterdam, Amsterdam, PO box 22,660 1100DD, The Netherlands. luukmunsterman@gmail.com
authors.forename: Luuk D H
authors.initials: LD
authors.lastname: Munsterman
authors.forename: Paul W G
authors.initials: PW
authors.lastname: Elbers
authors.forename: Alaattin
authors.initials: A
authors.lastname: Ozdemir
authors.forename: Eric P A
authors.initials: EP
authors.lastname: van Dongen
authors.forename: Mat
authors.initials: M
authors.lastname: van Iterson
authors.forename: Can
authors.initials: C
authors.lastname: Ince
mesh_terms: D000368:Aged; D001783:Blood Flow Velocity; D001794:Blood Pressure / Q000502:physiology; D005260:Female; D006801:Humans; D007423:Intra-Aortic Balloon Pumping / Q000009:adverse effects; D008297:Male; D008833:Microcirculation / Q000502:physiology*; D055806:Microvessels / Q000503:physiopathology; D009060:Mouth Floor / Q000098:blood supply*; D010092:Oximetry; D010100:Oxygen / Q000097:blood
chemical_list: D010100:Oxygen