Superior myocardial protection with nicorandil cardioplegia.
OBJECTIVE
The ATP-sensitive potassium channel (K(ATP)) activator nicorandil used as cardioplegic agent may protect the left ventricle during cardiac arrest. Nicorandil in cold blood was compared with standard hyperkalemic blood and crystalloid cardioplegia.


METHODS
Twenty-one pigs were randomly assigned to three groups: (1) cold hyperkalemic crystalloid (n=7); (2) cold hyperkalemic blood (n=7); and (3) nicorandil as cardioplegia in cold blood (n=7). Left ventricular mechanical performance, pressure-volume area (PVA) and myocardial oxygen consumption (MVO(2)) were measured before and at 1 and at 2 h after 60 min of cold global ischemia on cardiopulmonary bypass using intraventricular pressure-volume conductance catheters, coronary flow probes and O(2)-content difference.


RESULTS
The slope (M(w)) of the stroke work end-diastolic volume relationship, the preload recriutable stroke work relationship, was unchanged after ischemia in the nicorandil group, but was reduced to averaged 62.5% (standard deviation 14) of baseline values in both hyperkalemic perfusions (P<0.05). The slope of the MVO(2)-PVA relationship was unchanged after nicorandil cardioplegia while the slope after hyperkalemic blood and crystalloid cardioplegia increased with 33% (P<0.02) and 52% (P<0.02) of baseline values, respectively.


CONCLUSIONS
Nicorandil as sole cardioplegic agent in cold blood given intermittently preserves left ventricular contractility and myocardial energetics significantly better than traditional forms of cardioplegia after cardiac arrest.
Steensrud
T
T
Department of Cardiothoracic and Vascular Surgery, University Hospital of North Norway, Breivika, P.O. Box 102, N-9038 Tromsø, Norway. tors@fagmed.uit.no
Nordhaug
D
D
Elvenes
O P
OP
Korvald
C
C
Sørlie
D G
DG
D000818:Animals; D001769:Blood; D002314:Cardioplegic Solutions / Q000627:therapeutic use*; D002315:Cardiopulmonary Bypass; D003326:Coronary Circulation / Q000187:drug effects; D003331:Coronary Vessels / Q000502:physiology; D005260:Female; D006324:Heart Arrest, Induced / Q000379:methods*; D007036:Hypothermia, Induced; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects; D020108:Nicorandil / Q000627:therapeutic use*; D010101:Oxygen Consumption / Q000187:drug effects; D017680:Potassium Compounds / Q000627:therapeutic use; D011897:Random Allocation; D013552:Swine; D016277:Ventricular Function, Left / Q000187:drug effects
D002314:Cardioplegic Solutions; D017680:Potassium Compounds; C018369:potassium cardioplegic solution; D020108:Nicorandil