The Annals of Thoracic Surgery, Vol 22, 347-355, Copyright © 1976 by The Society of Thoracic Surgeons
Constant-pressure coronary artery perfusion during aortic valve operations
S Giannelli Jr, EF Conklin, RT Potter, EA Bonfils-Roberts, JT Mazzara and AH Moreno
We considered the theoretical differences between the normal relationships
of coronary blood flow and perfusion pressure in the working heart and
those obtained with continuous, steady-flow perfusion by a roller pump
during aortic valve replacement. Steady pump perfusion should deliver less
blood flow to the endocardium because: 1. For the same mean artery
perfusion pressure, the average coronary blood flow is less with
constant-flow pump perfusion. 2. With constant pump perfusion, pressure
would be excessively high during systole, and during diastole it would be
significantly lower than the mean perfusion pressure. Instantaneous
pressure and flow were measured in the left coronary artery in 8 patients
undergoing aortic valve replacement, employing either roller pump perfusion
or a gravity flow system to provide a steady pressure source. Although we
did not attempt to demonstrate improved endocardial flow, the mean left
coronary flow was always greater with gravity perfusion (297 versus 153
ml/min), lending support to the theoretically proposed differences between
the two perfusion methods.