Non-cardiac surgery in patients with severe aortic stenosis: time to revise the guidelines?

Many patients undergoing major non-cardiac surgery have a high risk of perioperative cardiovascular complications. Several studies have identified variables that are associated with this increased perioperative cardiovascular risk, 3 including arrhythmias, heart failure, recent myocardial infarction, and ischaemic heart disease. Aortic stenosis (AS) is not always included in cardiac risk prediction models, because it is regularly underdiagnosed and therefore also under-represented in databases and the resulting risk assessment tools. Nevertheless, severe AS is the most prevalent valvular heart disease in the elderly, many of whom regularly require non-cardiac surgery. Patients with AS have an obstruction in the outflow tract that gradually results in left ventricular myocardium hypertrophy. Initially, the cardiac output and left ventricular end-diastolic volumes are preserved, permitting patients to stay asymptomatic. Eventually, however, the concentric left ventricular hypertrophy and reduced compliance of the myocardium leads to diastolic dysfunction. At that point, patients develop symptoms of dyspnoea or chest pain due to the increased diastolic pressure of the left ventricle. In addition, the AS causes systemic hypotension and reduction of coronary flow reserve. When patients in this condition are exposed to the haemodynamic stress of a major surgical procedure, they are at higher risk of decompensated heart failure. Therefore, the European Society of Cardiology (ESC), European Association of Cardio-Thoracic Surgery (EACTS), and American College of Cardiology (ACC)/American Heart Association (AHA) Guidelines dedicate special sections to decision-making in noncardiac surgery for patients with severe AS. –7 These guidelines recommend postponing or cancelling non-cardiac surgery if severe AS is symptomatic, and recommend that surgical or transcatheter aortic valve replacement prior to non-cardiac surgery should be considered. For asymptomatic patients, the AHA guideline suggests postponing non-cardiac surgery if the valve has not been evaluated within 1 year. The ESC/EACTS guideline recommends proceeding with non-cardiac surgery in asymptomatic patients that are at low or moderate surgical risk for the non-cardiac surgery, whereas in high risk patients, the patients’ risk for surgical aortic valve replacement is decisive (Figure 1A). These recommendations are largely based on small and old observational studies. –11 Tashiro et al. now present a large contemporary study of patients with severe AS undergoing moderate to high risk non-cardiac surgery. By linking . 500 000 echocardiagrams with their surgical database, the authors were able to identify 256 patients with severe AS. These patients were matched to patients without AS based on age, gender, and year of surgery. There was no significant difference in 30-day mortality (5.9% vs. 3.1%, P 1⁄4 0.13). The rate of major adverse cardiovascular events (MACE; death, stroke, myocardial infarction, ventricular tachycardia/fibrillation, and heart failure) was higher in the severe AS group (18.8% vs. 10.5%, P 1⁄4 0.01), mainly due to higher rates of heart failure. In addition, emergency surgery was shown to be the strongest predictor of 30-day mortality. This important study has several implications for perioperative management of patients with severeAS and may even lead to revision of the aforementioned guidelines. The perioperative mortality rate was lower than previously reported. Therefore, the authors speculate that the threshold to proceed with the non-cardiac surgical procedure without treating a severe AS could be lowered. There are several potential reasons for the relatively low rate of mortality in this study, including improvements in surgical and anaesthesia techniques compared with earlier studies. However, outcomes in the symptomatic group (n 1⁄4 106) were markedly worse than in the asymptomatic group (n 1⁄4 150). In asymptomatic patients and their matched controls, mortality and MACE rates were practically equal ( 3% and 10–12%, respectively) in both patients with and without AS. On the other hand, in the patients with symptoms, MACE rates at 30 days were significantly higher compared with their controls (28.3% vs. 8.5%, P , 0.001), although the difference in mortality (9.4% vs. 3.8%) did not reach statistical significance (P 1⁄4 0.097). This suggests that the excellent outcomes of patients