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Effects of crystalloid and blood cardioplegic solutions on myocardial cooling during myocardial revascularization
Insights
Cardioplegic solution viscosity does not impact myocardial cooling distribution beyond coronary artery blockages. This finding is crucial for improving cardiac protection in patients with coronary artery disease undergoing revascularization.
Area of Science:
- Cardiology
- Cardiovascular Surgery
- Biomedical Engineering
Background:
- Impaired cardioplegic protection in coronary artery disease leads to temperature gradients and poor myocardial cooling.
- Cardioplegic solution viscosity may influence distribution beyond coronary artery stenosis.
Purpose of the Study:
- To compare the effects of asanguineous and blood cardioplegic solutions on myocardial cooling in patients with coronary artery disease.
- To determine if cardioplegic solution viscosity affects distribution beyond coronary artery stenosis.
Main Methods:
- 26 patients with coronary artery disease undergoing myocardial revascularization were studied.
- 15 patients received blood cardioplegia, and 11 received crystalloid cardioplegia.
- Regional myocardial temperature was measured distal to coronary artery obstructions after cardioplegic infusion.
Main Results:
- Blood cardioplegic solution viscosity was 250% greater than asanguineous solution.
- No significant difference in regional myocardial temperatures was observed beyond coronary artery stenosis.
- Significant temperature gradients were noted distal to critical stenoses, with temperatures ranging from 18-23°C.
Conclusions:
- The viscosity difference between crystalloid and blood cardioplegic solutions does not significantly affect distribution beyond coronary artery stenosis.
- Myocardial cooling remains impaired distal to coronary artery obstructions, irrespective of cardioplegic solution type or viscosity.
Abstract:
Cardioplegic protection during ischemic arrest is impaired in patients with serious coronary artery disease, resulting in large regional temperature gradients and impaired myocardial cooling. Recent data have suggested that the viscosity of cardioplegic solutions may affect their distribution beyond coronary artery stenosis. This study compared the effects of asanguineous and blood cardioplegic solutions on myocardial cooling in 26 such patients who underwent elective myocardial revascularization; 15 were subjected to blood cardioplegia and 11 to crystalloid cardioplegia. One litre of blood or asanguineous cardioplegic solution was infused into the aortic root at a constant infusion pressure. Samples for viscosity determination were taken from both cardioplegic solutions during their infusion. Regional myocardial temperature was measured distal to coronary artery obstructions following administration of the cardioplegic agent. Although the viscosity of the blood solution was 250% greater than the asanguineous solution, regional myocardial temperatures were not significantly different beyond the coronary artery stenosis. Regional temperature was reduced to less than 15 degrees C after infusion of the cardioplegic agent in regional myocardium with a normal coronary circulation. Marked temperature gradients were observed distal to a critical stenosis, with temperatures ranging between 18 degrees C and 20 degrees C for stenosis, and about 23 degrees C for obstruction. The authors conclude that the marked difference in viscosity between crystalloid and blood cardioplegic solutions does not significantly affect their distribution beyond a coronary artery stenosis.