Patients with impaired ventricular function exhibited profound limitations in extraction of all forms of metabolic fuels after global ischemia/reperfusion stress during cardiac surgery.
Observational (n=37)
Does preexisting coronary artery disease or left ventricular dysfunction alter myocardial metabolic substrate use during surgical ischemia/reperfusion in patients undergoing cardiac surgery?
Preexisting ventricular dysfunction is associated with global suppression of metabolic fuel uptake and limited metabolic reserve following surgical ischemia/reperfusion.
BACKGROUND: Human myocardial metabolism has been incompletely characterized in the setting of surgical cardioplegic arrest and ischemia/reperfusion. Furthermore, the effect of preexisting ventricular state on ischemia-induced metabolic derangements has not been established. METHODS AND RESULTS: We applied a mass spectrometry-based platform to profile 63 intermediary metabolites in serial paired peripheral arterial and coronary sinus blood effluents obtained from 37 patients undergoing cardiac surgery, stratified by presence of coronary artery disease and left ventricular dysfunction. The myocardium was a net user of a number of fuel substrates before ischemia, with significant differences between patients with and without coronary artery disease. After reperfusion, significantly lower extraction ratios of most substrates were found, as well as significant release of 2 specific acylcarnitine species, acetylcarnitine and 3-hydroxybutyryl-carnitine. These changes were especially evident in patients with impaired ventricular function, who exhibited profound limitations in extraction of all forms of metabolic fuels. Principal component analysis highlighted several metabolic groupings as potentially important in the postoperative clinical course. CONCLUSIONS: The preexisting ventricular state is associated with significant differences in myocardial fuel uptake at baseline and after ischemia/reperfusion. The dysfunctional ventricle is characterized by global suppression of metabolic fuel uptake and limited myocardial metabolic reserve and flexibility after global ischemia/reperfusion stress in the setting of cardiac surgery. Altered metabolic profiles after ischemia/reperfusion are associated with postoperative hemodynamic course and suggest a role for perioperative metabolic monitoring and targeted optimization in cardiac surgical patients.
Turer et al. (Tue,) conducted a observational in Coronary artery disease or left ventricular dysfunction (n=37). Surgical ischemia/reperfusion vs. Patients with vs without coronary artery disease or left ventricular dysfunction was evaluated on Myocardial substrate use (extraction ratios of metabolites). Patients with impaired ventricular function exhibited profound limitations in extraction of all forms of metabolic fuels after global ischemia/reperfusion stress during cardiac surgery.