Optimizing outcomes in Acute Type A Aortic Dissection: a call for specialized care

Abstract

Acute Type A Aortic Dissection is a life-threatening condition with high early mortality and long-term morbidity. Several factors influence outcomes, including advanced age, comorbidities, haemodynamic collapse, and organ malperfusion with ischaemia. Managing these cases requires a higher level of surgical expertise than elective aortic procedures due to the fragility of dissected tissue, cardiovascular instability, organ ischaemia, and bleeding tendencies. Paradoxically, these emergencies are often handled by less experienced surgeons during after-hours calls, frequently in non-aortic centres, as ambulances prioritize rapid access to operating theatres over specialized care.

I read with great interest the study by Knox et al.¹ in this issue of the journal, examining the relationship between case volume and mortality for both individual surgeons and surgical units in Australia. Utilizing retrospective data from the Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) Adult Cardiac Surgery Database (2001–2021), the study analyzed 2604 cases across 50 units and 167 surgeons. The 30-day mortality averaged 18%, showing a steady decline from nearly 30% in the early 2000s to around 15% over the last decade. A statistical technique called the funnel plot was used to assess institutional and individual performance against case volume.² The study concluded that while individual surgeon case volume impacted outcomes, this correlation was not observed at the unit level. However, the authors acknowledged that not all Australian units contributed data to the registry.

Recent literature supports the influence of experience and case volume on outcomes. Hou et al.³ found that once surgeons surpassed 25 cases, mortality consistently dropped below 10%, advocating for high-volume surgeons in high-volume centres. Lin et al.⁴ demonstrated that in an established aortic centre, early-career surgeons achieved equivalent mortality rates (11%–12%) compared to senior colleagues. Similarly, Harky et al.⁵ found no difference between daytime and night-time surgeries but reported a significant mortality reduction following the establishment of a dedicated aortic service. Anderson et al.⁶ echoed these findings, demonstrating mortality rates of approximately 10% in specialized centres. Additionally, Norton et al.⁷ reported superior outcomes for surgeries performed by specialized aortic surgeons compared to general cardiac surgeons.

Several confounding variables significantly impact outcomes but are not always controlled for in retrospective studies. These include the time from symptom onset to operating room (‘Dissection-to-OR’ time), exclusion criteria, prior exposure of surgeons to high-volume aortic centres during training, and senior supervision during surgery. For example, delayed presentation may lead to an artificially improved survival rate due to the early attrition of high-risk cases. Similarly, stringent exclusion criteria can skew results.

The critical question for Australia is whether we should accept that most units and surgeons operate within three standard deviations of an 18% mortality rate – or whether we should aim to replicate the practices of centres achieving sub-10% mortality. If the prevailing literature supports the superiority of specialized aortic centres with dedicated rosters of trained surgeons, then acute dissections should be preferentially referred to these centres. Given the geographic proximity of most cardiac units in Australian cities, ambulance transfer times would likely remain within acceptable limits. Failing this, we should insist that all trainees complete a rotation at a high-volume aortic centre to gain exposure to the complex nuances of dissection management.

The objective must be clear: no patient should face a worse outcome due to system inefficiencies or lack of access to experienced surgical care. It is time to reassess and optimize the management algorithm for Acute Type A Aortic Dissection in Australia.

George Matalanis: Conceptualization; resources; writing – original draft; review and editing.