Introduction
The extent of emergency repair following acute type-A aortic dissection (ATAAD), and in particular the decision whether to conserve the native aortic valve, remains an area of cardiac surgery without standardised practice [1]. In cases of ATAAD with known connective tissue disease, extension of the intimal tear into the root or aneurysmal dilation of the ascending aorta a decision to replace the native aortic valve at the time of emergency surgery is relatively straightforward. In many cases, however, the balance between a more extensive initial operation, incorporating replacement of the native aortic valve, compared to a simpler operation preserving the aortic valve, with a possible higher risk of subsequent re-intervention, is less clear [2][3].
ATAAD typically involves an intimal tear in the ascending aorta distal to the sinotubular junction, a pathological process which is complicated by acute aortic regurgitation in approximately half of cases [3][5]. Several mechanisms have been established for regurgitation in this situation including prolapse of the dissection flap through the aortic valve or leaflet prolapse due to disruption of their attachments to the aortic wall [6].
Deciding whether to preserve the native aortic valve in cases complicated by significant aortic regurgitation is typically determined by individual surgeon preference. However, ensuring aortic valve competency is an important marker of successful ATAAD repair. Surgeons opting for valve replacement can guarantee this, at least in the short term, where the goal is to perform the safest operation that maximises the chances of patient survival. A final decision on the surgical approach to treatment of the aortic valve cannot be taken until the aorta is opened. In addition to the decision regarding replacement of the aortic valve, the surgeon is faced with several other critical operative choices which must be made in a timely manner. These include alternative bypass strategies, cerebral protection, and the need to address the aortic arch.
Despite the well-reported advantages and disadvantages of both options, the factors predicting subsequent aortic regurgitation, dilation of the aortic root and re-intervention are still poorly understood due to the lack of long-term data. This retrospective case series compares the outcomes for patients undergoing preservation of the native aortic valve at the time of emergency surgery for type-A aortic dissection with a cohort of patients where the aortic valve was replaced. In the cohort of patients where the native aortic valve was conserved the echocardiographic performance of the native aortic valve and root was analysed by follow up transthoracic echocardiography.