ANNUAL QUEENSTOWN UPDATE IN ANAESTHESIA 2015 32 Cardiac Risk of Non-Cardiac Surgery Roman Kluger Department of Anaesthesia, St. Vincent’s Hospital Is it a problem? Yes – death directly due to anaesthesia is less than 1 in a few hundred thousand. However 30 day mortality and morbidity following surgery is common and much of it is cardiac. Worldwide more than 200 million adults have major non-cardiac surgical procedures annually. Millions of these patients will have a major vascular complication (vascular death, nonfatal myocardial infarction [MI], nonfatal cardiac arrest, or nonfatal stroke) within 30 days after surgery. Myocardial infarction is the most common major peri-operative vascular complication. For example in the original POISE (PeriOperative ISchemic Evaluation) study 1 1.6% died of vascular causes, 0.7% had a stroke, 0.5% had a non-fatal cardiac arrest, and 5.0% had an MI in the first 30 days. Overall postoperative vascular events account for one third of perioperative deaths and are associated with increased hospital stay and long-term mortality rates. Why estimate risk? 1. To inform patient and surgeon decision making. Most surgery is elective and often can be postponed or even cancelled. Less invasive surgical alternatives may be available and more appropriate. 2. To inform peri-operative management. Risk reduction strategies must aim at high risk patients. For example pre-operative troponins, BNP levels and stress testing; invasive haemodynamic monitoring and tighter blood pressure and heart rate control during surgery; and postoperative monitoring in high dependency /ICU, postoperative troponins and long term follow-up and prophylactic cardiac medications. However at this stage none of these strategies have been convincingly shown to safely decrease morbidity or mortality. Peri-operative Myocardial Infarction The risk of an MI in the postoperative period is far higher than at any other period and its prognosis is worse (approximately double the mortality of an outpatient MI) because the postoperative period is a period of inflammation, hypercoagulability, stress, hypoxia and anaemia. Analysis of the POISE data, where all patients had daily cardiac enzymes, ECGs and clinical evaluations provided much information regarding postoperative MIs 2 . 5% of the patients had a postoperative MI and the 30 day mortality was higher for patients who had an MI (11.6%) than for those who did not (2.2%). 74% of MIs occurred within 48 hours of surgery. 58% of patients who had an MI died with 48 hours of the event. Of the patients who had an MI 65% did not have ischaemic symptoms, and the mortality rate was similar between those who did and did not have symptoms. 8.3% of patients had elevated levels of cardiac enzymes (but did not fulfil MI definition) and were also at higher risk of adverse cardiac events. See figure 1. Only 10.6 % of the MIs had ST elevation.