title: IABP timing and ventricular performance--comparison between a compliant and a stiffer aorta: a hybrid model study including baroreflex.
abstract: BACKGROUND
  The aim of this study was to investigate the effects of the intra aortic balloon pump (IABP) and of aortic compliance on left ventricular performance, including the effects of baroreflex control.
  
  
  METHODS
  The study was conducted using a hybrid cardiovascular simulator, including a computational cardiovascular sub-model, a hydraulic sub-model of the descending aorta, and a baroreflex computational sub-model. A 40 cc balloon was inserted into a rubber tube component of the hydraulic sub-model. A comparative analysis was conducted for two aortic compliances (C1 = 2.4 and C2 = 1.43 cm3/mmHg, corresponding to an aortic pulse pressure of 23 mmHg and 35 mmHg, respectively), driving the balloon for different trigger timings.
  
  
  RESULTS
  Under C1 conditions, the IABP induced higher effects on baroreflex activity (decrement of sympathetic efferent activity: 10% for C1 and 14.7% for C2) and ventricular performance (increment of cardiac output (CO): 3.7% for C1 and 5.2% for C2, increment of endocardial viability ratio (EVR): 24.8% for C1 and 55% for C2). The best balloon timing was different for C1 and C2: inflation trigger timing (from the dicrotic notch) -0.09 s for C1 and -0.04 s for C2, inflation duration 0.25 s for C1 and 0.2 s for C2.
  
  
  CONCLUSIONS
  Early inflation ensures better EVR, CO, and an increment of the afferent nerve activity, hence causing peripheral resistance and heart rate to decrease. The best balloon timing depends on aortic compliance, thus suggesting the need for a therapy tailored to the specific conditions of individual patients.
authors: Section of Rome, Institute of Clinical Physiology, National Research Council, Rome - Italy and Nale?cz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, Warsaw - Poland.
authors: Libera
authors: L
authors: Fresiello
authors: Ashraf W
authors: AW
authors: Khir
authors: Arianna
authors: A
authors: Di Molfetta
authors: Maciej
authors: M
authors: Kozarski
authors: Gianfranco
authors: G
authors: Ferrari
mesh_terms: D001011:Aorta; D017704:Baroreflex; D001794:Blood Pressure; D006352:Heart Ventricles; D006353:Heart-Assist Devices; D006439:Hemodynamics; D006801:Humans; D007423:Intra-Aortic Balloon Pumping