Within 30 days of non-cardiac surgery, one in 10 patients will have a major vascular complication. In the CCC State-of-the-Art lecture, Dr. PJ Devereux of McMaster University brought to the fore work being done to reduce myocardial injury after non-cardiac surgery (MINS).
Surgery is stressful, and many assessment tools don’t identify all individuals at risk. Dr. Devereux emphasized the need for both pre-operative and post-operative assessment to identify patients at risk. Pre-operatively, nuclear stress and echocardiography tests are not that effective. CT angiography looks promising, and the Heart Institute’s Dr. Ben Chow is participating in a multicentre study to evaluate this.
Dr. Devereux’s work indicates that measuring post-operative troponin T levels is the best way to identify a patients MINS risk. Troponins are proteins key to cardiac muscle contraction. In fact, Dr. Devereux and colleagues have defined MINS as a troponin T level of .03 or higher, well below widely accepted levels. Of patients with MINS under this definition, 34 per cent will die.
Preventing perioperative vascular complications is not straightforward. Beta blockers reduce MINS but increase serious stroke, and aspirin has no clear evidence behind it. A clinical trial is underway to look at the use of anticoagulants because most fatal events are due to blood clots. Dr. Devereux expects that continuing to monitor troponin after discharge will be an important way forward.