Augmentation Index in an Animal Model of Myocardial Ischemia-Reperfusion and Heart Failure: a Preliminary Report

Cardiovascular indices are useful to evaluate myocardial damage and the effectiveness of medical interventions during ischemic heart failure. Left ventricular thickening has been used to evaluate myocardial ischemia generated by transitory induced coronary occlusion. Ischemic alterations can be quantified using the wall thickening fraction (WTF). Likewise, the augmentation index (AIx) is used to estimate the elasticity of an artery by observing the influence of incident and reflected waveforms in the systolic aortic pressure. WTF and the AIx indices were calculated using data obtained from an animal model with induced heart failure and transient myocardial ischemia, followed and a reperfusion stage. The relationship between both indices was analyzed. The analysis of the relationship between WTF and AIx during heart failure and reperfusion stage showed: a) a positive correlation in six animals (p<;0.05), b) a negative relationship in eight animals (p<;0.05), and c) no significant correlation in 16 animals. Results obtained in the animal model partially demonstrated the possibility of obtaining information about the left ventricular wall function using an index based on arterial pressure signals. Since AIx can be non-invasively calculated in clinical practice, further research would be necessary in order to elucidate the origin of the different WTF-AIx relationships observed in this work.