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Preconditioning the human heart during aorto-coronary bypass surgery
A M Alkhulaifi1, D M Yellon, W B Pugsley
1Department of Cardiothoracic Surgery, Middlesex Hospital, London, UK.
Summary
Controlled aortic cross-clamping may mimic ischaemic preconditioning. This study found that preconditioning significantly depleted myocardial adenosine triphosphate (ATP) but preserved it during subsequent ischaemia compared to controls.
Area of Science:
- Cardiology
- Biochemistry
- Surgical Research
Background:
- Ischaemic preconditioning enhances myocardial resistance to infarction and preserves adenosine triphosphate (ATP).
- Intermittent aortic cross-clamping in surgery shares similarities with preconditioning.
- This study investigates aortic cross-clamping as a preconditioning method.
Purpose of the Study:
- To test if controlled aortic cross-clamping acts as a preconditioning stimulus.
- To evaluate myocardial ATP conservation as an endpoint for preconditioning.
Main Methods:
- Patients were randomized into preconditioned (n=10) and control (n=10) groups.
- The preconditioned group received two 3-min cross-clamping periods with 2-min reperfusion.
- Myocardial ATP, creatine phosphate, and lactate were measured via biopsy at three time points.
Main Results:
- Preconditioning significantly depleted myocardial ATP (11.7 ± 0.9 vs 19.8 ± 1.4 μmol/g dry weight).
- Control group experienced significant ATP depletion after 10 min of ischaemia (7.2 ± 0.3 vs 19.5 ± 1.2 μmol/g dry weight).
Conclusions:
- Controlled aortic cross-clamping appears to induce a preconditioning effect.
- Further research is needed to fully understand the mechanisms of ATP conservation during surgical interventions.