Evidences for Inotropism Triggered by Simultaneous Antegrade And Retrograde Myocardial Perfusion in A Swine Model

Objectives: Retrograde perfusion into the coronary sinus is currently used to deliver cardioplegia. We developed an in-vivo porcine beating-heart model of self-myocardial retroperfusion (SMR) using the venous route to increase myocardial oxygenation of the left ventricle. Then, we sought to assess whether the association of a simultaneous antegrade and retrograde myocardial perfusion with oxygenated blood might trigger hemodynamic and cardiac responses compared with a single antegrade myocardial supply. Methods: A group of 8 pigs was dedicated to undergo SMR with a simultaneous antegrade physiological LAD perfusion. SMR was achieved with a bypass-line between the ascending aorta and the coronary sinus to perform a selective retrograde perfusion of the great cardiac vein with oxygenated blood after ligation of the left azygos vein. Cardiac output (CO), maximal pressure in the LV (Pmax in-LV), stroke volume (SV), left ventricular ejection fraction (LVEF), diastolic durations, heart rate (HR), and arterial systemic pressure were monitored with conductance catheters. These data were collected during the antegrade myocardial perfusion (baseline period) and compared with data recorded during a simultaneous antegrade and retrograde perfusion. At the end of the procedures, the hearts were harvested for histology. Results: SMR with antegrade LAD perfusion showed inotropic properties with significant improvements in CO, SV, Pmax in-LV and LVEF (p<0.0001) compared with baseline values. Histology confirmed no signs of tissular injuries. Conclusions: The selective retrograde perfusion of the great cardiac vein with oxygenated blood combined with an antegrade physiological LAD perfusion showed obvious capacities to trigger inotropic properties opening interesting perspectives.