O. Irtun et Dg. Sorlie, DELIVERY PRESSURE OF THE CARDIOPLEGIC SOLUTION INFLUENCES MYOCARDIAL PROTECTION, European journal of cardio-thoracic surgery, 9(3), 1995, pp. 139-142
To investigate whether cardioplegic solution (CS) delivery pressure in
fluences myocardial protection, intermittent infusions of CS at differ
ent pressures were used in an isolated Langendorff rat heart preparati
on. In group 1 the hearts were kept arrested for 210 min at 12 degrees
C with intermittent infusions of 5 ml CS every 20 min at 30 cm H2O (2
2 mmHg) pressure, in group 2 the same volume of CS was infused at 100
cm H2O (73.5 mmHg) pressure, in group 3 at 145 cm H2O (106.5 mmHg) pre
ssure and in group 4 at 238 cm H2O (175 mmHg) pressure. There was a si
gnificantly higher coronary resistance in groups 1 and 4 (7.3+/-0.2 RU
and 6.9+/-0.2 RU) than in groups 2 and 3 (4.2+/-0.2 RU and 4.2+/-0.2
RU) (P < 0.05) during the ischemic period. There were no significant d
ifferences between group 2 and 3 in the reperfusion period. Groups 2 a
nd 3 showed higher coronary flow and left ventricle developed pressure
than group 1 and 4. Hearts from group 1 and 4 had Lower adenosine tri
phosphate (7.88+/-0.44 mu mol.g(-1), 5.56+/-0.56 mu mol.g(-1)) (P < 0.
05) and creatine phosphate (24.66+/-0.47 mu mol.g(-1), 15.34+/-0.94 mu
mol.g(-1)) (P < 0.05) content at the end of the reperfusion period th
an group 2 (10.56+/-0.41 mu mol.g(-1), 30.06+/-0.38 mu mol.g(-1)) and
group 3 (14.13+/-0.69 mu mol.g(-1), 35.25+/-0.78 mu mol. g(-1)). These
results indicate that with antegrade, intermittent, hypothermic, hype
rkalemic cardioplegic infusion both a low delivery pressure (22 mmHg)
and a high delivery pressure (175 mmHg) are associated with suboptimal
myocardial protection.