Smooth muscle-dependent changes in aortic wall dynamics during intra-aortic counterpulsation in an animal model of acute heart failure.
OBJECTIVE
Intra-aortic balloon pumping (IABP) may modify arterial biomechanics; however, its effects on arterial wall properties during acute cardio-depression have not yet been fully explored. This dynamical study was designed to characterize the effects of IABP on aortic wall mechanics in an in vivo animal model of acute heart failure.


METHODS
Aortic pressure, diameter and blood flow were measured in six anesthetized sheep with acute cardio-depression by halothane (4%), before and during IABP (1:2). Aortic characteristic impedance and aortic wall stiffness indexes were calculated.


RESULTS
acute experimental cardio-depression resulted in a reduction in mean aortic pressure (p<0.05) and an increase in the characteristic impedance (p<0.005), incremental elastic modulus (p<0.05), stiffness index (p<0.05) and Peterson elastic modulus (p<0.05). IABP caused an increase in the cardiac output (p<0.005) and a reduction in the systemic vascular resistances (p<0.05). In addition, the aortic impedance, incremental elastic modulus, stiffness index and Peterson modulus were significantly reduced during IABP (p<0.05).


CONCLUSIONS
Our findings show that IABP caused changes in aortic wall impedance and intrinsic wall properties, improving the arterial functional capability and the left ventricular afterload by a reduction in both. Systemic vascular resistances and aortic stiffness were also improved by means of smooth muscle-dependent mechanisms.
Cabrera Fischer
Edmundo I
EI
Basic Sciences Research Institute & FICEN-Favaloro University, Buenos Aires, Argentina.
Bia
Daniel
D
Zócalo
Yanina
Y
Armentano
Ricardo L
RL
D000208:Acute Disease; D000818:Animals; D001011:Aorta / Q000503:physiopathology*; D001696:Biomechanical Phenomena; D001794:Blood Pressure; D002302:Cardiac Output; D004195:Disease Models, Animal; D055119:Elastic Modulus; D006221:Halothane; D006333:Heart Failure / Q000139:chemically induced / Q000503:physiopathology / Q000628:therapy*; D006439:Hemodynamics; D007423:Intra-Aortic Balloon Pumping; D008955:Models, Cardiovascular; D009131:Muscle, Smooth, Vascular / Q000503:physiopathology*; D012039:Regional Blood Flow; D012756:Sheep; D014655:Vascular Resistance; D018487:Ventricular Dysfunction, Left / Q000139:chemically induced / Q000503:physiopathology / Q000628:therapy*
D006221:Halothane