Reducing the cardiac risks in noncardiac surgery

Cardiac events are the major cause of morbidity and mortality in patients undergoing non-cardiac surgery, and new guidelines issued today by the European Society of Cardiology address this common and complicated challenge.

The risk of cardiac complications depends on the condition of the patient prior to surgery, the prevalence of heart disease, and the magnitude and duration of the surgical procedure. After major surgery the incidence of cardiac death varies between 0.5% and 1.5%, and of non-fatal cardiac complications between 2.0% and 3.5%. When applied to the population in the European Union member states these figures translate into 150,000 to 250,000 life-threatening cardiac complications resulting from non-cardiac surgical procedures annually.

The guidelines recommend a practical, stepwise evaluation of the patient, which integrates cardiac risk factors and test results with the estimated stress of the planned surgical procedure. The guidelines focus on non-cardiac surgery - that is, with heart disease as a potential source of complications during surgery, and not the heart as the target of therapy.

Cardiac complications are more likely to occur in patients with documented or asymptomatic ischaemic heart disease, left ventricular dysfunction, and valvular heart disease undergoing surgical procedures associated with prolonged haemodynamic and cardiac stress. The guidelines therefore recommend preoperative assessment of clinical risk factors, such as heart failure, previous myocardial infarction, and diabetes mellitus, to stratify patients according to risk of cardiac events.

However, the use of additional cardiac testing, such as echocardiography or exercise testing, is only recommended for patients with multiple risk factors scheduled for high risk surgery, in order to assess the presence and extent of ischaemic heart disease. Non-invasive testing should be considered for preoperative revascularization, patient counselling, change of perioperative management in relation to type of surgery, and anaesthesia technique. Emphasis is put on a restricted use of prophylactic coronary revascularisation, as this is rarely indicated just to get the patient through surgery.

Preoperative cardiac risk evaluation also offers a unique opportunity to identify and treat risk factors. The initiation of lifestyle changes and medical therapy for cardiac risk factors should be done prior to surgery, as interventions improve both perioperative and late outcome.

The guidelines make other clear recommendations:

1. The cause of perioperative cardiac events are complex, the assumption that a single drug can intervene in all these factors is unlikely. A combination of beta-blockers, statins, aspirin, and angiotensin converting enzyme inhibitors are probably the best medical option.
2. A low-dose of beta-blocker, timely started prior to surgery is recommended. Beta-blocker dose should be titrated to achieve heart rate between 60 and 70 per minute.
3. Statins with a long half life time or extended release formulations are recommended, to bridge the period immediately after surgery when oral intake is not feasible.
4. Aspirin therapy should be continued, and only stopped in those in which haemostasis is difficult to control during surgery.
5. Preoperative coronary intervention using stents should be discussed with the treating surgeon and anaesthesiologist, as anti-platelet therapy (aspirin and/ or clopidogrel) influences perioperative management. A patient should live long enough to enjoy the benefits of surgery.

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