Management of the cardiac risk patient

Surgery-induced hyperdynamic cardiac responses compromise the myocardial oxygen supply ratio. Patients with coronary artery disease are therefore at risk of peri-operative myocardial ischaemia, which may result in an adverse cardiac outcome. A predominant effect of α2-adrenergic drugs is a modulation of the central sympathetic tone, thereby preventing catecholamine release, hypertension and tachycardia. The protective cardiac and anti-ischaemic effects of α2-adrenergic agonists are well documented in animals. Cardiac surgery and vascular surgery patients were studied using clonidine, mivazerol and dexmedetomidine. There is good evidence that, in humans, α2-agonists protect the heart at risk of peri-operative ischaemia, especially in high-stimulation phases intra-operatively and post-operatively. The greatest benefit of peri-operative therapy with α2-adrenergic agonists is documented for vascular surgery patients. Besides their anti-ischaemic effect, clonidine and dexmedetomidine are associated with a greater need for intervention to treat hypotension and bradycardia