Which techniques of cardioplegia prevent ischemia?
One hundred seven patients undergoing coronary artery bypass grafting were randomized to receive warm antegrade (n = 21), warm retrograde (n = 22), cold antegrade (n = 20), cold retrograde (n = 22), or intermittent cold antegrade (n = 22) blood cardioplegia. Myocardial oxygen consumption and lactate production, adenine nucleotides, and adenine nucleotide degradation products were measured during the operation, and creatine kinase-MB release was assessed postoperatively. Warm cardioplegia resulted in greater myocardial lactate production than cold cardioplegia (p = 0.048). Retrograde cardioplegia was associated with greater lactate production than antegrade cardioplegia (p = 0.015). Adenosine triphosphate depletion was similar among groups. However, poorly diffusible metabolites of adenosine triphosphate accumulated to the greatest extent in the intermittent cold group. Levels of hypoxanthine were highest after warm retrograde cardioplegia. Operative mortality and morbidity were low and were not different among groups. In summary, none of the five techniques of cardioplegia evaluated in this study was able to completely prevent myocardial ischemia. Anaerobic lactate production was minimized with cold cardioplegia and with antegrade cardioplegic delivery. Hypothermia may have impaired regeneration of adenosine triphosphate, however, particularly in association with inadequate or intermittent cardioplegic flow.
Yau
T M
TM
Division of Cardiovascular Surgery, Toronto Hospital, Ontario, Canada.
Ikonomidis
J S
JS
Weisel
R D
RD
Mickle
D A
DA
Hayashida
N
N
Ivanov
J
J
Carson
S
S
Mohabeer
M K
MK
Tumiati
L C
LC
D000249:Adenosine Monophosphate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D001783:Blood Flow Velocity; D001804:Blood Transfusion, Autologous; D001026:Coronary Artery Bypass / Q000379:methods*; D003402:Creatine Kinase / Q000097:blood; D005260:Female; D006321:Heart / Q000503:physiopathology*; D006324:Heart Arrest, Induced / Q000379:methods*; D006439:Hemodynamics; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007036:Hypothermia, Induced / Q000379:methods; D007527:Isoenzymes; D007773:Lactates / Q000378:metabolism; D019344:Lactic Acid; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000517:prevention & control*; D015425:Myocardial Reperfusion / Q000379:methods; D009206:Myocardium / Q000378:metabolism*; D010101:Oxygen Consumption; D011184:Postoperative Period; D013696:Temperature; D013997:Time Factors; D016896:Treatment Outcome
D007527:Isoenzymes; D007773:Lactates; D019344:Lactic Acid; D000249:Adenosine Monophosphate; D000255:Adenosine Triphosphate; D003402:Creatine Kinase