Outcomes of type A aortic dissection in Australia

Introduction: Without surgical intervention, type A aortic dissection (TAAD) carries a high risk of life-threatening complications and mortality. Due to the low incidence of aortic dissection, case numbers vary significantly between institutions. This study reports outcomes for patients undergoing surgical TAAD repair in Australia between 2001 and 2021, and the impact of institution case numbers on mortality. 

Methods: Retrospective multicentre cohort study using the Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) data, including consecutive adult patients undergoing surgery for TAAD. Patients were divided into groups based on 30-day mortality. Secondary morbidity outcomes are reported. 

Results: Between 2001 and 2021, 2604 patients (median age 65; 67% male) underwent operative intervention for TAAD. Over this period, the number of aortic dissections recorded in the database annually increased (from <50 to >200 cases per year), consistent with the increasing number of contributing institutions. Thirty-day mortality rates varied by unit from 0% to 100%, with an average over the period of 18%. Despite unit case numbers ranging from 1 or 2 to over 200 cases, funnel plot analysis demonstrated no units fell outside the accepted 99.7% control level for 30-day mortality. Individual surgeons showed decreased mortality with increased caseload. Non-survivors were more likely to have prior respiratory or cerebrovascular disease, previous myocardial infarction, or severe left ventricular dysfunction. Post-operative stroke, return to theatre for bleeding, renal failure and atrial fibrillation were more common in the non-survivors (P < 0.05). 

Conclusion: Mortality outcomes for TAAD in Australia have improved over time, stabilizing at 18% over the last 5 years. Units performing fewer operations for TAAD showed equivalent mortality outcomes to high volume units, while surgeons performing fewer procedures displayed a higher mortality.