Related Experiment Videos
Changes in serum cyclic nucleotide concentration during open-heart surgery
Insights
Serum cyclic adenosine monophosphate (cAMP) increased in coronary sinus blood after open-heart surgery, while cyclic guanosine monophosphate (cGMP) decreased. Lower cAMP and higher cGMP levels correlated with impaired spontaneous heart recovery after surgery.
Area of Science:
- Cardiology
- Biochemistry
- Physiology
Background:
- Open-heart surgery often involves myocardial ischemia.
- Cold cardioplegia is used to protect the heart during surgery.
- Cyclic nucleotides (cAMP and cGMP) play roles in cellular energy regulation and function.
Purpose of the Study:
- To investigate changes in serum cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) concentrations during open-heart surgery with cold cardioplegia.
- To correlate these changes with spontaneous recovery of heart function post-surgery.
Main Methods:
- Blood samples were collected from the radial artery and coronary sinus of 14 patients during open-heart surgery.
- Samples were analyzed for cAMP and cGMP levels before aortic cross-clamping and at 1 and 9 minutes after declamping.
- Statistical analysis was performed to assess significant changes and correlations.
Main Results:
- Serum cAMP levels significantly increased in the coronary sinus after aortic declamping, with no significant arterial changes.
- Serum cGMP levels significantly decreased after aortic release, followed by an increase at 9 minutes.
- Patients with spontaneous heart recovery had lower cAMP and higher cGMP levels compared to those without recovery.
Conclusions:
- Cold cardioplegia affects myocardial cyclic nucleotide levels during open-heart surgery.
- Altered cAMP and cGMP dynamics may indicate myocardial sensitivity to hypoxia and energy resource utilization.
- These findings suggest potential biomarkers for predicting spontaneous cardiac recovery after surgical procedures.
Abstract:
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.