DOES SIMULTANEOUS ANTEGRADE RETROGRADE CARDIOPLEGIA IMPROVE MYOCARDIAL PERFUSION IN THE AREAS AT RISK - A MAGNETIC-RESONANCE PERFUSION IMAGING STUDY IN ISOLATED PIG HEARTS/
Gh. Tian et al., DOES SIMULTANEOUS ANTEGRADE RETROGRADE CARDIOPLEGIA IMPROVE MYOCARDIAL PERFUSION IN THE AREAS AT RISK - A MAGNETIC-RESONANCE PERFUSION IMAGING STUDY IN ISOLATED PIG HEARTS/, Journal of thoracic and cardiovascular surgery, 115(4), 1998, pp. 913-924
Objective: This study was designed to determine whether simultaneous a
ntegrade/retrograde cardioplegia improves myocardial perfusion in area
s supplied by occluded vessels. Methods: Isolated pig hearts placed in
a Langendorff preparation were divided into two groups. The left ante
rior descending coronary artery was occluded at its origin. In group 1
(n = 7), simultaneous antegrade/retrograde cardioplegia was conducted
with use of a single perfusion unit with tubing in a Y-shaped configu
ration at the end, joined to the aorta and the coronary sinus. In grou
p 2 (n = 8) simultaneous antegrade/retrograde cardioplegia was perform
ed with two separate units, one for antegrade delivery of cardioplegic
solution and the other for retrograde cardioplegic solution delivery.
Myocardial perfusion in the region supplied by the left anterior desc
ending artery and the region not supplied by this artery was assessed
by magnetic resonance imaging, with use of a magnetic resonance contra
st agent. The contrast agent was introduced into the common perfusion
line in group 1 and into the aortic line only in group 2, Results: Mag
netic resonance images showed that the myocardium in the region suppor
ted by the left anterior descending artery could not be perfused with
antegrade cardioplegic solution because of occlusion of the artery. Du
ring simultaneous antegrade/retrograde cardioplegia, however, the myoc
ardium in the left anterior descending region was perfused by approxim
ately 40% to 50% (group 1) or 20% to 30% (group 2) of the degree of pe
rfusion in the region not perfused by the left anterior descending art
ery (100%), Almost no cardioplegic solution was delivered to the heart
through the coronary sinus route during simultaneous antegrade/retrog
rade cardioplegia in both groups of hearts, Myocardial perfusion in th
e region supported by the left anterior descending artery was heteroge
neous during simultaneous antegrade/retrograde cardioplegia. Conclusio
ns: Simultaneous antegrade/retrograde cardioplegia significantly impro
ved myocardial perfusion in jeopardized areas of the myocardium, The j
eopardized myocardium was mainly perfused by the solution drained from
the adjacent normal tissue. Elevated pressure at the coronary sinus d
uring simultaneous antegrade/retrograde cardioplegia is responsible fo
r the redistribution of antegradely delivered cardioplegic solution.