title: End-diastolic flow reversal limits the efficacy of pediatric intra-aortic balloon pump counterpulsation.
abstract: BACKGROUND
  Counterpulsation with an intra-aortic balloon pump (IABP) has not achieved the same success or clinical use in pediatric patients as in adults. In a pediatric animal model, IABP efficacy was investigated to determine whether IABP timing with a high-fidelity blood pressure signal may improve counterpulsation therapy versus a low-fidelity signal.
  
  
  METHODS
  In Yorkshire piglets (n = 19; weight, 13.0 ± 0.5 kg) with coronary ligation-induced acute ischemic left ventricular failure, pediatric IABPs (5 or 7 mL) were placed in the descending thoracic aorta. Inflation and deflation were timed with traditional criteria from low-fidelity (fluid-filled) and high-fidelity (micromanometer) blood pressure signals during 1:1 support. Aortic, carotid, and coronary hemodynamics were measured with pressure and flow transducers. Myocardial oxygen consumption was calculated from coronary sinus and arterial blood samples. Left ventricular myocardial blood flow and end-organ blood flow were measured with microspheres.
  
  
  RESULTS
  Despite significant suprasystolic diastolic augmentation and afterload reduction at heart rates of 105 ± 3 beats per minute, left ventricular myocardial blood flow, myocardial oxygen consumption, the myocardial oxygen supply/demand relationship, cardiac output, and end-organ blood flow did not change. Statistically significant end-diastolic coronary, carotid, and aortic flow reversal occurred with IABP deflation. Inflation and deflation timed with a high-fidelity versus low-fidelity signal did not attenuate systemic flow reversal or improve the myocardial oxygen supply/demand relationship.
  
  
  CONCLUSIONS
  Systemic end-diastolic flow reversal limited counterpulsation efficacy in a pediatric model of acute left ventricular failure. Adjustment of IABP inflation and deflation timing with traditional criteria and a high-fidelity blood pressure waveform did not improve IABP efficacy or attenuate flow reversal. End-diastolic flow reversal may limit the efficacy of IABP counterpulsation therapy in pediatric patients with traditional timing criteria. Investigation of alternative deflation timing strategies is warranted.
authors.affiliation: Division of Cardiovascular Surgery, University of Pennsylvania, Philadelphia, Pa; MD/PhD Program, University of Louisville School of Medicine, Louisville, Ky.
authors.forename: Carlo R
authors.initials: CR
authors.lastname: Bartoli
authors.affiliation: University of Louisville School of Medicine, Louisville, Ky.
authors.forename: Benjamin D
authors.initials: BD
authors.lastname: Rogers
authors.affiliation: Cardiovascular Innovation Institute, University of Louisville, Louisville, Ky.
authors.forename: Constantine E
authors.initials: CE
authors.lastname: Ionan
authors.affiliation: Cardiovascular Innovation Institute, University of Louisville, Louisville, Ky; Department of Bioengineering, University of Louisville, Louisville, Ky; Department of Surgery, University of Louisville, Louisville, Ky. Electronic address: gmpant02@louisville.edu.
authors.forename: George M
authors.initials: GM
authors.lastname: Pantalos
mesh_terms: D000367:Age Factors; D000818:Animals; D001794:Blood Pressure; D003326:Coronary Circulation; D004195:Disease Models, Animal; D006333:Heart Failure / Q000209:etiology / Q000378:metabolism / Q000503:physiopathology / Q000628:therapy*; D006339:Heart Rate; D006353:Heart-Assist Devices; D007423:Intra-Aortic Balloon Pumping / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods*; D017202:Myocardial Ischemia / Q000150:complications; D009206:Myocardium / Q000378:metabolism; D010101:Oxygen Consumption; D013552:Swine; D013997:Time Factors; D018487:Ventricular Dysfunction, Left / Q000209:etiology / Q000378:metabolism / Q000503:physiopathology / Q000628:therapy*; D016277:Ventricular Function, Left