Is blood superior to crystalloid cardioplegia? A meta-analysis of randomized clinical trials.
BACKGROUND
Many small, randomized, controlled trials have evaluated the effectiveness of blood as compared with crystalloid cardioplegia for myocardial protection during cardiac surgery. Blood cardioplegia provides a closer approximation to normal physiology, which may translate into measurable clinical benefits. This meta-analysis describes the effectiveness of blood cardioplegia in lowering adverse postoperative outcomes.


RESULTS
MEDLINE, EMBASE, and the Cochrane registry of controlled trials were searched for clinical trials. The search was restricted to peer-reviewed English language publications of randomized controlled trials that primarily compared blood and crystalloid cardioplegia in adult patients. Each trial was blindly assessed and abstracted by 2 reviewers. The primary outcomes were: low output syndrome (LOS), myocardial infarction (MI), and death. Surrogate outcomes included postoperative creatinine kinase MB (CKMB) increase. Random effects summary odds ratio (OR) for binary outcomes, and weighted mean difference for continuous outcomes were calculated. A total of 34 trials were included. The majority of trials were conducted in patients undergoing elective CABG surgery (n=18). The incidence of LOS was decreased significantly with blood cardioplegia (OR, 0.54; 95% confidence interval [CI], 0.34 to 0.84; P=0.006; 879 patients, 10 trials). The incidence of MI and death were similar between treatment groups (MI: OR, 0.78; 95% CI, 0.54 to 1.13; 4316 patients, 23 trials) (death: OR, 0.80; 95% CI, 0.46 to 1.40; 4022 patients, 17 trials). CKMB release after surgery at 24 hours was reduced with blood cardioplegia (5.9 U/L; 95% CI, 1.6 to 10.2; P=0.007; 821 patients, 7 trials).


CONCLUSIONS
Blood cardioplegia provides superior myocardial protection as compared with crystalloid cardioplegia, including lower rates of LOS, and early CKMB increase, whereas the incidence of myocardial infarction and death are similar.
Guru
Veena
V
Division of Cardiovascular Surgery, Sunnybrook and Women's College Health Sciences Centre, 2075 Bayview Avenue, H-410, Toronto, Ontario M4N 3M5 Canada. veena.guru@utoronto.ca
Omura
John
J
Alghamdi
Abdullah A
AA
Weisel
Richard
R
Fremes
Stephen E
SE
D000368:Aged; D015415:Biomarkers; D001769:Blood; D002303:Cardiac Output, Low / Q000453:epidemiology / Q000517:prevention & control; D002314:Cardioplegic Solutions / Q000494:pharmacology*; D001026:Coronary Artery Bypass; D052279:Creatine Kinase, MB Form / Q000097:blood; D000077324:Crystalloid Solutions; D017558:Elective Surgical Procedures; D005260:Female; D006324:Heart Arrest, Induced / Q000009:adverse effects / Q000379:methods*; D006801:Humans; D015994:Incidence; D007431:Intraoperative Complications / Q000401:mortality; D007552:Isotonic Solutions; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000453:epidemiology / Q000517:prevention & control; D015428:Myocardial Reperfusion Injury / Q000097:blood / Q000517:prevention & control; D016017:Odds Ratio; D011183:Postoperative Complications / Q000453:epidemiology / Q000517:prevention & control; D016032:Randomized Controlled Trials as Topic / Q000706:statistics & numerical data; D016037:Single-Blind Method; D013696:Temperature; D016896:Treatment Outcome
D015415:Biomarkers; D002314:Cardioplegic Solutions; D000077324:Crystalloid Solutions; D007552:Isotonic Solutions; D052279:Creatine Kinase, MB Form