Abstract
BackgroundCoronary artery bypass surgery can be performed without (Off-Pump) or with cardiopulmonary bypass (On-Pump). Extracorporeal circulation and cardioplegic arrest may cause alterations in the plasma metabolome. We assessed metabolomic changes in patients undergoing On-Pump or Off-Pump coronary artery bypass surgery.MethodsWe assessed five analyte classes (41 acylcarnitines, 14 amino acids, 92 glycerophospholipids, 15 sphingolipids, sugars, lactate) using a mass-spectrometry-based kit (Biocrates AbsoluteIDQ® p150) in paired arterial and coronary sinus blood obtained from 10 consecutive On-Pump and 10 Off-Pump patients. Cardioplegia for On-Pump was warm blood Calafiore. On-Pump outcomes were corrected for hemodilution through crystalloid priming.ResultsDemographic data were equal in both groups with normal ejection fraction, renal and liver function. Patients received 2.25 ± 0.64 bypass grafts. All postoperative courses were uneventful. Of 164 measured metabolites, only 13 (7.9%) were altered by cardiopulmonary bypass. We found more long-chain acylcarnitines Off-Pump and more short-chain acylcarnitines On-Pump. Glycerophospholipids showed lower concentrations On-Pump and arginine (as the only different amino acid) Off-Pump. Interestingly, plasma arginine (nitric oxide precursor) concentration at the end of surgery correlated inversely with postoperative vasopressor need (r = −0.7; p < 0.001). Assessing arterial/venous differences revealed phosphatidylcholine-production and acylcarnitine-consumption. These findings were unaffected by cardiopulmonary bypass, cardioplegia or temporary vessel occlusion during Off-Pump surgery.ConclusionsCardiopulmonary bypass and warm blood cardioplegia cause only minor changes to the metabolomic profile of patients undergoing coronary artery bypass surgery. The observed changes affected mainly acylcarnitines. In addition, there appears to be a relationship between arginine and vasopressor need after bypass surgery.
Highlights
Coronary artery bypass surgery can be performed without (Off-Pump) or with cardiopulmonary bypass (On-Pump)
The On-Pump patients had high arginine concentrations and low postoperative noradrenaline doses and, vice versa, Off-Pump patients had low arginine concentrations but higher postoperative noradrenaline requirements. We demonstrate in this manuscript that cardiopulmonary bypass and warm blood cardioplegia cause only minor changes to the metabolomic profile of patients undergoing bypass surgery and that acylcarnitines are elevated in both Off-Pump and On-Pump, but chain lengths differ
We demonstrate that there appears to be a correlation between arterial arginine concentration and vasopressor need after bypass surgery
Summary
Coronary artery bypass surgery can be performed without (Off-Pump) or with cardiopulmonary bypass (On-Pump). We assessed metabolomic changes in patients undergoing On-Pump or Off-Pump coronary artery bypass surgery. Recent studies have shown that specific metabolic profiles may independently predict adverse events after coronary artery bypass grafting (CABG) [1] or in heart failure patients and after left ventricular assist device (LVAD) implantation [2]. While these investigations addressed the metabolic signatures either before and/or. We hypothesized that patients undergoing CABG On-Pump and those operated Off-Pump would show substantial differences in their plasma metabolomic profile. We tested our hypothesis in a proof-of-principle type study using targeted metabolomic analysis
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