DRUG-THERAPY IN CORONARY HEART-DISEASE - PERIOPERATIVE IMPLICATIONS

Objective: The aim of our review is to summarize relevant data on the perioperative use of anti-ischaemic drugs in patients at risk for or w ith proven coronary heart disease. Data sources. The accessible medica l literature according to current electronic information sources was e xplored. Results. One in every eight general anaesthetics is administe red to a patient at risk for or with proven coronary heart disease. Of these patients, it is estimated that 20%-40% have perioperative myoca rdial ischaemia (PMI), the majority being nonsymptomatic. This figure correlates with the occurrence of postoperative cardiac complications and myocardial infarction. The anaesthetist therefore has an important role to play in reducing the rate of perioperative cardiac sequelae. This can be achieved with good control of haemodynamic stability and t he timely and appropriate use of anti-ischaemic drugs. Nitrocompounds (nitrates, molsidomine) serve as the gold standard in current angina p ectoris treatment. Acting as coronary and systemic vasodilators, they effect an immediate reduction in preload and have been shown to be the drugs of first choice for intra-operative myocardial ischaemia. Beta- blockers reduce the rate of PMI to a greater extent than nitrates. The y are also effective in myocardial ischaemia not accompanied by an inc reased heart rate. Single pre-operative administration of beta-blocker s has also been shown to be beneficial in reducing theincidence of per ioperative tachycardia, hypertension, and PMI. Consequently, such one- time medication can be considered for previously untreated high-risk p atients presenting for surgery. The continuation of oral calcium chann el blockers to the morning of surgery also reduces the rate of PMI and myocardial infarction in coronary-bypass patients, and combination wi th beta-blockers enhances this effect. Intra-operative diltiazem infus ions are similarly advantageous in this patient group. In addition to nitrates, calcium antagonists are the drug of choice for coronary vaso spasm. Drugs inhibiting platelet aggregation have a particular role in patients with coronary heart disease, however, they also cause increa sed perioperative bleeding. Consequently, it is recommended that these medications be discontinued 5-10 days prior to major surgery, with th e exception of high-risk patients. Pilot studies using alpha2-agonists have shown reduced anaesthetic requirements and a reduction in PMI. T he perioperative relevance of these drugs is currently being investiga ted. Conclusions. Beta-blockers, calcium channel blockers, nitrates, a nd possibly alpha2-agonists lead to reduced rates of PMI and other car diac complications in risk patients. Current anti-anginal medications, with the exception of anti-platelet agents, should be maintained to t he day of surgery and continued as soon as possible thereafter. All of these drugs except anti-platelet agents may also be used intra-operat ively, however, possible interactions with anaesthetic agents should b e carefully considered.