Changes in serum cyclic nucleotide concentration during open-heart surgery.
Changes in serum cyclic AMP and GMP concentrations were studied in 14 patients undergoing open-heart surgery with cold cardioplegia. Blood samples were taken on total bypass from the radial artery and from the coronary sinus before aortic cross-clamping and 1 and 9 min after declamping. The samples were analyzed for cyclic nucleotides. The cAMP levels showed no pronounced change in the arterial samples, but were significantly increased in the coronary sinus samples after declamping of the aorta. The cGMP values showed the same trend of change in the arterial and the coronary sinus samples, viz. significant fall after aortic release, and after 9 min an increase. The cAMP/cGMP ratio after clamp removal showed pronounced increase in the first minute and some reduction at 9 min. All the changes were statistically significant. Beating recommenced spontaneously in seven hearts. The cAMP levels were lower in this group than in the patients without spontaneous recovery. The outset cGMP levels and the cAMP/cGMP ratio were higher in the latter group. Absence of increase in the cGMP level may be due to effectiveness of cardioplegia in reducing the energy requirements of the ischemic myocardium. The study indicates that hearts without spontaneous recovery of beating react more sensitively to hypoxia and have to use up more of their energy resources for restoration of function.
D000328:Adult; D001158:Arteries; D006348:Cardiac Surgical Procedures; D000242:Cyclic AMP / Q000097:blood*; D006152:Cyclic GMP / Q000097:blood*; D005260:Female; D006324:Heart Arrest, Induced; D006801:Humans; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction; D009206:Myocardium / Q000378:metabolism
D000242:Cyclic AMP; D006152:Cyclic GMP