posted on 2020-12-07, 22:36authored byVishal Shah, Oleg Orlov, Konstantadinos Plestis
A 45-year-old male hypertension presented with severe chest and back
pain. Computed tomography (CT) scan revealed a type A aortic dissection
extending into the abdominal aorta. Intraoperative transesophageal
echocardiogram demonstrated severe central aortic insufficiency with a
dissection flap in the ascending aorta. The patient had distal palpable
pulses and no signs of malperfusion.
General anesthesia was induced and the patient received invasive
hemodynamic monitoring with a right heart catheter and bilateral
arterial lines. This is important particularly in cases that the
axillary artery is cannulated for arterial inflow since the right radial
pressure is falsely elevated when the patient is on cardiopulmonary
bypass (CBP). An activated clotting time > 480 seconds indicates
adequate anticoagulation before initiating CBP. Aminocaproic acid was
used. Near infrared spectroscopy (Somanetics Corp., Troy, MI) was also
used to confirm symmetric cerebral perfusion during the operation. The
patient’s head was packed in ice once cooling began.
An
infraclavicular incision was performed to expose the right axillary
artery. The right axillary artery was cannulated using an 8 mm side
graft. Next, cannulation of the right atrium and the coronary sinus were
performed. The patient was placed on cardiopulmonary bypass and was
cooled to 24°C (minimum cooling time is 30 minutes). During cooling, the
innominate vein as well as the innominate and left carotid artery were
mobilized. The aorta was then cross-clamped 2 cm proximal to the
innominate artery and electromechanical arrest was achieved with
cardioplegia given in a retrograde fashion. A transverse aortotomy was
performed 2 cm above the sinotubular junction. There was an intimal tear
1 cm above the sinotubular junction. The dissection extended proximally
in the aortic root. The aortic root was mobilized by dividing its
attachments to the pulmonary artery and dome of the left atrium. Three
4-0 pledgeted polypropylene sutures were placed at the tip of the 3
commissures and secured, effectively resuspending the aortic valve. The
integrity of the aortic valve was easily assessed by pulling the
commissural sutures tight, securing them in the operative field, and
applying suction on the aortic valve.
Given the extensive
involvement of the aortic root and the age of the patient, a decision
was made to perform a valve sparing surgery. Then the right and left
main coronary buttons were mobilized from inside the root. The
noncoronary sinus was excised. The aortic valve had normal cusp
morphology. A circumferential series of 2-0 Ethibond pledgeted annular
sutures were placed underneath the annulus of the aortic valve in a
clockwise fashion, beginning at the nadir of the noncoronary sinus.
These sutures were placed in a horizontal plane formed by the base of
the interleaflet triangles between the noncoronary and left coronary
sinuses, with exceptions at the left coronary/right coronary and right
coronary/noncoronary commissures. The precise height of each commissure
was measured, transposed onto the graft, and the graft was trimmed in
these areas. The subvalvular sutures were passed through a 32 Valasalva
graft aortic graft. The graft was positioned and fastened with an
automated suture fastener device over a 23 Hagar dilator. The
commissures were secured at the appropriate height within the graft with
4-0 pledgeted polypropylene suture. Subsequently, the circumference of
the aortic valve apparatus was secured to the graft with running 4-0
polypropylene sutures. The competency of the aortic valve was
reassessed. The left coronary button was reimplanted into the graft with
Teflon-reinforced continuous full-thickness 5-0 polypropylene sutures.
Since the right coronary button was dissected circumferentially, a 6 mm
graft was anastomosed to the right coronary opening with 5-0
polypropylene suture using the Cabrol technique to prevent undue tension
and bleeding. This graft was subsequently anastomosed to an opening in
the main graft.
Deep hypothermic circulatory arrest was initiated
at 24°C. The aortic arch was inspected. There was a secondary tear
between the left carotid and the innominate artery. The aorta was then
transected between the innominate and left common carotid arteries. The
innominate artery was transected at its base. A 12 mm graft was
anastomosed to the innominate artery with 5-0 Prolene in a continuous
fashion. The graft was de-aired and clamped, and flow was re-established
into the right common carotid artery via the right axillary graft. A
Pruitt catheter was placed in the left carotid artery to deliver
supplemental antegrade cerebral perfusion. Antegrade cerebral flow was
established at 8-10 cc/kg per minute with a perfusion pressure between
50-70 mm Hg, a temperature of 24°C, and a hematocrit of 25%. Alpha stat
was used for pH monitoring. Cerebral perfusion was monitored with
cerebral oximetry.
A 32 mm Valsalva graft was anastomosed to the
aorta just proximal to the takeoff of the left common carotid artery
using 4-0 Prolene continuous suture with Teflon-felt reinforcement. The
12 mm graft was then anastomosed to the 32 mm graft in end-to-side
fashion. The graft was de-aired, clamped, and flow was re-established to
the rest of the body. Rewarming was begun.
The two grafts were
then anastomosed to each other using 4-0 Prolene in continuous fashion,
and the clamp was removed. After the patient was rewarmed, and de-airing
of the heart was achieved under transesophageal echocardiographic (TEE)
guidance, the patient was weaned off cardiopulmonary bypass. TEE
demonstrated that the aortic valve was competent, and the left and right
ventricular functions were normal. The chest was closed in standard
fashion. The patient was discharged home on postoperative day 12.