Does enflurane-nitrous oxide anaesthesia and surgical stimulation alter regional coronary haemodynamics in a patient with an LAD bypass graft?
Enflurane-nitrous oxide anesthesia and surgical stimulation can compromise regional coronary blood flow in patients with LAD grafts and collateral circulation due to coronary steal and vasoconstriction.
Central and regional coronary haemodynamics were studied in a patient with a left anterior descending artery (LAD) graft and angiographically visible collaterals from a normal right coronary artery. A three-thermistor thermodilution catheter was used for measuring total coronary sinus blood flow and great cardiac venous blood flow, the latter being a good representative of blood flow through the LAD. Enflurane-nitrous oxide anaesthesia induced marked coronary vasodilatation and redistribution of blood flow from the LAD to other areas draining into the coronary sinus. The most likely mechanism for the redistribution of blood flow in this patient was steal via the collaterals between the LAD and the right coronary artery. During surgical stimulation, the flow through the LAD was further compromised due to pronounced coronary vasoconstriction, probably mediated by catecholamine release.
S. Reiz (Sat,) studied this question.
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