title: Left ventricular unloading with intra-aortic counter pulsation prior to reperfusion reduces myocardial release of endothelin-1 and decreases infarction size in a porcine ischemia-reperfusion model.
abstract: OBJECTIVE
  We tested the hypothesis that unloading the left ventricle with intra-aortic balloon counter-pulsation just prior to reperfusion provides infarct salvage compared with left ventricular (LV) unloading postreperfusion or reperfusion alone.
  
  
  BACKGROUND
  Previous reports demonstrated infarct salvage with complete LV unloading with an LVAD prior to reperfusion; however, partial LV unloading using intra-aortic balloon pumps (IABPs) has not been evaluated.
  
  
  METHODS
  Twenty-eight Yorkshire pigs were subjected to 1 hr of left anterior descending artery occlusion and 4 hr of reperfusion. An IABP was inserted and activated just prior to reperfusion (IABP-Pre), or 15 min after reperfusion (IABP-Post), or not at all (control).
  
  
  RESULTS
  At baseline, the hemodynamic data were similar in the three groups. Myocardial infarct size expressed a percentage of zone at risk in control animals was 44.9% +/- 4.8%, IAPB-Pre group 20.9% +/- 5.1% (P < 0.05 compared to control), and IABP-Post group 33.2 +/- 6.1% (P = 0.16 vs. control group). There was a correlation between transcardiac endothelin-1 release at 15 min postreperfusion and infarct size (r = 0.59).
  
  
  CONCLUSIONS
  LV unloading with an IABP prior to reperfusion reduces the extent of myocardial necrosis in hearts subjected to 1 hr of left anterior descending artery occlusion and 4 hr of reperfusion compared with either reperfusion alone or LV unloading after reperfusion. Inhibition of myocardial ET-1 release by LV unloading may be a significant mechanism of myocardial protection. These data suggest that in high-risk STEMI patients, IABP unloading prior to reperfusion might be more beneficial than IABP placement postreperfusion.
authors.affiliation: Division of Cardiovascular Medicine, University of Texas Health Science Center at Houston, 77030, USA.
authors.forename: John F
authors.initials: JF
authors.lastname: LeDoux
authors.forename: Sophie
authors.initials: S
authors.lastname: Tamareille
authors.forename: Patty R
authors.initials: PR
authors.lastname: Felli
authors.forename: James
authors.initials: J
authors.lastname: Amirian
authors.forename: Richard W
authors.initials: RW
authors.lastname: Smalling
mesh_terms: D015906:Angioplasty, Balloon, Coronary / Q000009:adverse effects; D000818:Animals; D003326:Coronary Circulation; D004195:Disease Models, Animal; D019332:Endothelin-1 / Q000378:metabolism*; D006353:Heart-Assist Devices; D006439:Hemodynamics; D007423:Intra-Aortic Balloon Pumping / Q000295:instrumentation; D009203:Myocardial Infarction / Q000378:metabolism / Q000503:physiopathology / Q000517:prevention & control*; D015428:Myocardial Reperfusion Injury / Q000378:metabolism / Q000503:physiopathology / Q000517:prevention & control*; D009206:Myocardium / Q000378:metabolism* / Q000473:pathology; D009336:Necrosis; D013552:Swine; D013997:Time Factors; D016277:Ventricular Function, Left
chemical_list: D019332:Endothelin-1