2.Operative Technique:
A re-implantation technique (David V) was performed in all patients. All
patients underwent emergency surgery with CPB initiated with arterial
cannulation via the right axillary artery and venous cannulation of the
right atrium, then general cooling was started. The ascending aorta was
cross clamped and myocardial protection was ensured through antegrade
cold crystalloid cardioplegia followed by intermittent administration of
selective coronary cardioplegia throughout the clamping time. Resection
of the aortic root leaving 3 to 4 mm of aortic remnants above the aortic
valve annulus was done systematically. Six sub-annular U stiches were
placed and anchored to a Valsalva Dacron tube (28-30mm diameter). The
aortic valve commissures were attached within the Valsalva Dacron tube.
At a rectal temperature of 28 °C, and with cerebral monitoring by NIRS,
hypothermic peripheral circulatory arrest was started. Cerebral
perfusion was ensured by blood injection (7.5 to 10 ml/kg/min) into the
right subclavian artery and by clamping the origin of the
Brachiocephalic artery and the Left Common Carotid artery. Exploration
of the aortic arch demonstrated no supplementary entry tears in any
patient. Transection of the aorta was performed 1 cm proximal to the
origin of the Innominate trunk. A 55-55 mm uncovered AMDS was
systematically used and deployed over a guidewire in the true lumen of
the descending aorta. Anastomosis between the aorta and the AMDS collar
was performed with a addition of a Dacron tube and reinforced by an
external Teflon felt. General cardiopulmonary bypass was then
re-initiated for rewarming after the aortic arch was purged and the
Dacron tube clamped .
During rewarming time, re-implantation of the aortic remanents into the
valsalva Dacron tube with running 4.0 Polypropylene sutures then
re-implantation of the coronary ostia were performed. In one patient,
the dissection reached the coronary right ostium needing repair. End to
end anastomosis between the two Dacron tubes was done using before
declamping and CPB was weaned in a standard manner withour inotropic
support in any patient.