Epidemiology, mortality and miss rate of acute aortic syndrome in Ontario, Canada: a population-based study

Introduction — Acute aortic syndrome (AAS) is a life-threatening emergency. It describes three distinct diagnoses: acute aortic dissection, acute intramural hematoma and penetrating atherosclerotic ulcer. There are currently no accurate estimates for incidence, mortality or misdiagnosis. Our objectives were to determine the incidence, mortality and miss rate of acute aortic syndrome in the emergency department (ED).

Methods — A population-based retrospective cohort study of anonymously linked data for residents of Ontario, Canada, was carried out. Incident cases of acute aortic syndrome were identified between 2003 and 2018 using a validated algorithm based on ICD-10 codes and death. Incidence (number of cases/population of Ontario), mortality, and miss rate were calculated. Miss rate was defined as when a patient was seen in the ED within 14 days prior to an acute aortic syndrome diagnosis with a presenting complaint consistent with acute aortic syndrome.

Results — There were 1299 cases of acute aortic syndrome over the study period [age mean (SD) 68.03 ± 14.70; female (n = 500, 38.5%); rural areas (n = 111, 8.6%)]. The overall annual incidence for acute aortic syndrome was 0.61 per 100,000. One year mortality decreased from 47.4 to 29.1%. ED mortality was 14.9%. In the 14 days prior to diagnosis 12.5% of patients were seen in the ED with a presentation consistent with acute aortic syndrome.

Conclusions — Annual incidence of acute aortic syndrome was found to be lower than other population-based studies. Also, the burden of mortality is seen in the ED. Education initiatives should focus on the identification of acute aortic syndrome in the ED to address mortality and miss rate.