Magnesium-supplemented warm blood cardioplegia in patients undergoing coronary artery revascularization.
BACKGROUND
Although there is growing evidence to suggest that the administration of magnesium (Mg2+) to patients undergoing coronary artery bypass grafting (CABG) and to patients after myocardial infarction is beneficial, the addition of Mg2+ to cardioplegic solutions remains controversial. The aim of this study was to compare the effects of intermittent warm blood cardioplegia with and without Mg2+ supplementation on the early postoperative clinical outcomes in patients undergoing both elective or urgent CABG.


METHODS
Four hundred patients undergoing CABG were prospectively randomized to receive either blood cardioplegia without Mg2+ (BC, n = 200) or supplemented with Mg2+ (BC-Mg2+, n = 200). Serial plasma Mg2+ concentrations were recorded at base line and postoperatively from days 1 to 4.


RESULTS
Patient characteristics were similar and no significant differences were found in early mortality and morbidity in the two groups. Analysis of 178 patients undergoing urgent CABG for unstable symptoms (BC = 95, BC-Mg2+ = 83) demonstrated a significantly lower requirement for internal defibrillation and temporary epicardial pacing in the BC-Mg2+ group. Furthermore, there was a nearly twofold lower incidence of new postoperative atrial fibrillation in the BC-Mg2+ group compared with the BC group (19% versus 34%, p = 0.03). Postoperative plasma Mg2+ levels were consistently lower in those patients who developed new postoperative atrial fibrillation compared with those who did not (p = 0.05).


CONCLUSIONS
The addition of Mg2+ to warm blood cardioplegia resulted in a lower incidence of intraoperative and postoperative arrhythmias in patients undergoing urgent CABG for unstable angina.
Yeatman
Mark
M
Bristol Heart Institute, University of Bristol, United Kingdom.
Caputo
Massimo
M
Narayan
Pradeep
P
Lotto
Attilio A
AA
Ascione
Raimondo
R
Bryan
Alan J
AJ
Angelini
Gianni D
GD
D000368:Aged; D001281:Atrial Fibrillation / Q000097:blood / Q000209:etiology; D002314:Cardioplegic Solutions / Q000737:chemistry*; D001026:Coronary Artery Bypass / Q000009:adverse effects; D004311:Double-Blind Method; D005260:Female; D006324:Heart Arrest, Induced / Q000379:methods*; D006801:Humans; D007431:Intraoperative Complications / Q000517:prevention & control; D008274:Magnesium / Q000097:blood / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000517:prevention & control; D011446:Prospective Studies
D002314:Cardioplegic Solutions; D008274:Magnesium