Myocardial metabolism is better preserved after blood cardioplegia in infants.
BACKGROUND
We have previously reported improved hemodynamic function after blood cardioplegia in comparison with crystalloid cardioplegia. Furthermore, lactate was released from the heart after crystalloid cardioplegia but not after blood cardioplegia. The purpose of this study was to determine whether the difference in substrate metabolism between the two cardioplegia methods was restricted to lactate, or whether the difference in metabolic derangement was more extensive.


METHODS
Thirty consecutive infants with complete atrioventricular septal defects were included in this prospective, randomized, controlled study. Arterial and coronary sinus blood concentrations of substrates and amino acids were measured after weaning from bypass.


RESULTS
After crystalloid cardioplegia, there was a myocardial uptake of glutamate (p = 0.003), leucine (p = 0.03), lysine (p = 0.003), and beta-hydroxybutyrate (p = 0.004), whereas lactate was released (p = 0.03). After blood cardioplegia, there was a myocardial uptake of free fatty acids (p = 0.01) but no uptake of amino acids and no release of lactate.


CONCLUSIONS
There are differences in myocardial substrate metabolism between blood cardioplegia and crystalloid cardioplegia, which involve carbohydrates and amino acids. The differences may include lipids but our data in this respect are not conclusive.
Amark
Kerstin
K
Department of Pediatrics, The Queen Silvia Children's Hospital, Göteborg, Sweden. kerstin.amark@vgregion.se
Berggren
Håkan
H
Björk
Kerstin
K
Ekroth
Annica
A
Ekroth
Rolf
R
Nilsson
Krister
K
Sunnegårdh
Jan
J
D020155:3-Hydroxybutyric Acid / Q000097:blood; D000596:Amino Acids / Q000097:blood*; D001011:Aorta; D001639:Bicarbonates / Q000494:pharmacology; D001769:Blood; D001786:Blood Glucose / Q000032:analysis; D002122:Calcium Chloride / Q000494:pharmacology; D002314:Cardioplegic Solutions / Q000494:pharmacology*; D002315:Cardiopulmonary Bypass; D003331:Coronary Vessels; D017558:Elective Surgical Procedures; D004734:Energy Metabolism; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D006324:Heart Arrest, Induced / Q000379:methods*; D006343:Heart Septal Defects / Q000097:blood / Q000601:surgery; D006801:Humans; D007223:Infant; D007773:Lactates / Q000097:blood*; D008274:Magnesium / Q000494:pharmacology; D008297:Male; D017202:Myocardial Ischemia / Q000378:metabolism / Q000517:prevention & control; D009206:Myocardium / Q000378:metabolism*; D010100:Oxygen / Q000097:blood; D011189:Potassium Chloride / Q000494:pharmacology; D017680:Potassium Compounds / Q000494:pharmacology*; D011446:Prospective Studies; D012965:Sodium Chloride / Q000494:pharmacology
D000596:Amino Acids; D001639:Bicarbonates; D001786:Blood Glucose; D002314:Cardioplegic Solutions; D005230:Fatty Acids, Nonesterified; D007773:Lactates; D017680:Potassium Compounds; C041711:St. Thomas' Hospital cardioplegic solution; C018369:potassium cardioplegic solution; D012965:Sodium Chloride; D011189:Potassium Chloride; D008274:Magnesium; D002122:Calcium Chloride; D010100:Oxygen; D020155:3-Hydroxybutyric Acid