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.