The Annals of Thoracic Surgery, Vol 38, 232-236, Copyright © 1984 by The Society of Thoracic Surgeons
Identification and control of noncoronary collateral blood flow
SF Bolling, KR Kanter, JT Flaherty, VL Gott and TJ Gardner
To identify the source of noncoronary collateral myocardial blood flow and
to establish methods to control it during induced ischemia, 29 dogs were
placed on cardiopulmonary bypass. The right and left ventricles were
vented, vent flows were measured volumetrically, and intracavitary left
ventricular (LV) pressures were monitored. After induction of ischemia by
aortic cross-clamping and infusion of cardioplegic solution, six different
microspheres 7 to 10 microns in diameter were injected into the aorta at
six different times to measure myocardial blood flow during the following
interventions:vent drainage of the right or left ventricle or both,
proximal ligation of both coronary arteries, severance of the proximal
pulmonary artery or the ascending aorta or both, and ligation of the
bronchial arteries. Without effective LV venting, LV intracavitary pressure
rose to 7.0 +/- 0.1 mm Hg (mean +/- standard error of the mean) and
myocardial blood flow in the anterior left ventricle was 2.3 +/- 1.3 ml/100
gm/min. When the LV vent was opened, vent flow was 35.9 +/- 3.5 ml/min and
myocardial blood flow fell to 0.3 +/- 0.2 ml/100 gm/min. Right ventricular
(RV) vent flow was absent except when the LV vent was occluded, and this RV
vent flow was abolished by ligating the coronary arteries. With bronchial
artery ligation, LV vent flow ceased and myocardial blood flow was
virtually absent. These studies demonstrate that myocardial blood flow does
occur during induced ischemia, but that the source of this blood flow is
primarily through systemic-pulmonary channels. True noncoronary collateral
myocardial blood flow was virtually nonexistent.