Keywords
aneurysm - dissection - open surgical management - Florida sleeve - frozen elephant
trunk
Introduction
Type A aortic dissection is a catastrophic surgical emergency with well-known high
morbidity and mortality, despite constant improvements in its management.[1] Important tools of the therapy are (1) replacement of diseased aorta in various
amounts and (2) follow-up and treatment of the distal aortic patent false lumen. Use
of the frozen elephant trunk technique is very well described in the setting of Type
A aortic dissection for the repair of aortic arch and the proximal intrathoracic aorta.
It is under debate which surgical technique to use when there is aortic root involvement
and the aortic valve structure is preserved. The following case report demonstrates
a radical approach to Type A aortic dissection in one single stage: sparing of the
aortic valve, reinforcement of the aortic root, and total replacement of the ascending
aorta, aortic arch, and proximal descending-thoracic aorta.
Case Presentation
A 60-year-old Caucasian male, nondiabetic, smoker with past medical history of hypertension
was admitted to a peripheral hospital after an episode of a transient loss of consciousness,
with a suspected diagnosis of alcoholic hangover. The patient reported chest pain.
On physical examination, he was cold, and sweaty, with a grade-II diastolic murmur
heard best at the left middle sternal border. Blood pressure was140/60 mm Hg and heart
rate was 90/min. A 12-lead electrocardiogram (ECG) showed normal sinus rhytm and inverted
T waves in inferior leads. Blood examinations revealed a mild increase of high sensitive
troponin (68 ng/dL; normal range <40 ng/dL). The transthoracic bidimensional echocardiography
(TTE) revealed severe aortic regurgitation, a 5-cm ascending aortic aneurysm and mild
pericardial effusion. Computed tomography (CT) angiograph demonstrated Type A aortic
dissection, extending upward to the supra-aortic vessels, and distally to the common
iliac arteries, with partial occlusion of right internal carotid artery ([Figs. 1] and [2]). The patient was immediately transferred to our institution for emergent cardiac
surgery.
Fig. 1 Contrast-enhanced computed tomography. (A) Axial section of the upper thorax shows the dissection flap (shown by red arrow)
in the aortic arch. The true lumen is anterior (shown by red asterisks) and the false
lumen is posterior; (B) coronal section of thorax and abdomen shows the Type A aortic dissection involving
the ascending and abdominal aorta and proximal segment of the aortic arch, with an
image of spiral intimal flap and “cobweb sign” of the false lumen (shown by red arrow).
Fig. 2 (A, B) Volume rendering of entire aorta with the image of spiral intimal flap (shown by
red arrows) dividing the true and false lumens and running parallel to the longitudinal
axis of aorta (C, D) Volume rendering of the intrathoracic aorta; (C) posterior view with spiral intimal flap, showing the true and false lumen in the
distal aortic arch; (D) axial section showing the true and false lumens in the ascending and descending
aorta. The spiral intimal flap is shown by red arrows. The true lumen is shown by
red asterisks.
Operative technique: full monitoring was established, with ECG, bilateral radial artery
cannulation, and central venous line insertion. After median sternotomy and a small
inferior cervicotomy along the anterior border of sternocleidomastoid muscle, the
right intrathoracic subclavian artery was prepared and cannulated, with interposition
of an 8-mm prosthesis. The right atrium was cannulated with a two-stage cannula. Cardiopulmonary
bypass (CPB) was instituted and systemic cooling started. At 30°C, the ascending aorta
was clamped and crystalloid cardioplegia was given. Under cardioplegic arrest, the
dissected ascending aorta was transected and excised, the aortic root was skeletonized
completely, and circumferentially mobilized down to the aortic annulus level. Due
to dilatation of Valsava sinus without involvement in the dissection and the preserved
aortic valve structure, it was decided to repair the aortic root and the ascending
aorta using the Florida sleeve aortic root technique with a bio-Valsalva prosthesis
(Vascutek Gelweave Valsalva Graft).
Six Ethibond 3–0 U-stiches were passed at the annulus level (nadir + commissure) and
the bio-Valsalva prosthesis was affixed. The aortic root and the aortic valve were
pulled in and the sinotubular junction was sutured to the prosthesis. The sizing of
bio-Valsalva's prosthesis was chosen considering dimension and form of native aortic
root to avoid further deformation or dilatation and to preserve ventriculoaortic junction
anatomy, the aortic leaflets attachment and the sinotubular junction, and the so-called
functional aortic annulus (geometric approach). We have created specific bottom on
the prothesis to accept the coronary artery ostia and sutured the prosthesis to the
sinus above the coronary ostia to avoid its following avulsion. The coronary arteries
were not involved in the dissection.
Thereafter the left common carotid and left subclavian arteries (via an interposed
graft) were cannulated and the brachiocephalic trunk was clamped, so that total antegrade
cerebral perfusion was obtained.
The aortic arch was completely resected. The Thoraflex system was gently bent and
then advanced into the descending thoracic aorta. Once the stent graft had been deployed,
the distal anastomosis was performed. The fourth branch of the graft was cannulated,
the prosthesis clamped, and lower body reperfusion and partial rewarming initiated.
Sequential reattachment of left subclavian and left common carotid arteries to the
side branches of the Thoraflex was performed. The dissected ascending aorta was resected
and a proximal prosthesis-to-prosthesis anastomosis was then performed. Due to complex
damage of the innominate artery, arch reconstruction was completed using the 8-mm
graft as an extranatomical bypass. The aortic clamp was removed, the myocardium was
reperfused, and systemic rewarming accomplished.
Subsequently, CPB was easily weaned off with low dose inotropic support. Operative
times were as follows: total CPB time, 200 minutes; aortic cross-clamp, 120 minutes;
Kazui's time, 28 minutes.
The postoperative course was uneventful. The patient was neurologically intact. The
postoperative CT angiogram scan demonstrated total reconstruction of the aortic arch,
patent connection of the branches, and partial thrombosis of the persistent false
lumen in the descending thoracic aorta ([Fig. 3]).
Fig. 3 (A, B) Postoperative two-dimensional echocardiogram: parasternal long axis view. (A) Native aortic valve sparing and reinforcement of the aortic root (shown by red arrows),
(B) color flow mapping, in the parasternal long axis view, shows no aortic regurgitation.
(C, D) Volume rendering of the thorax, left (C) and right (D) sagittal views, showing Vascutek Thoraflex hybrid prosthesis in aortic arch and
descending aorta. The Vascutek Thoraflex is shown by white arrows.
The patient was discharged to a rehabilitation facility after 10 days. At 6-month
follow-up, the patient was symptomless. Echocardiogram showed no aortic regurgitation
or pericardial effusion ([Fig. 3]).
Discussion
This case report demonstrates the contemporaneous use of the Florida sleeve technique
plus the Vascutek Thoraflex frozen elephant trunk hybrid prosthesis in an acute Type
A aortic dissection.
Acute Type A aortic dissection carries approximately 56% in-hospital mortality when
surgical intervention is not performed.[2] Surgical series show a 30-day mortality of 10 to 20%.[3]
Different techniques have been applied to treat a widely dissected, aneurysmal aortic
root, including the Bentall–De Bono and David operations.[4] The appropriate technique is controversial when there is aortic root involvement
and the native aortic valve is normal. New hemodynamic conceptions regarding the importance
of avoiding aortic root deformation to optimize transvalvular ejection throughout
the cardiac cycle open a new scenario in terms of aortic root replacement or repair.[5]
The Florida sleeve operation has been proposed as an alternative method to repair
the aortic root and to spare the aortic valve, in the setting of annuloaortic ectasia.
Gamba et al[6] demonstrated satisfactory long-term outcome after application of the Florida sleeve
technique with a mean clinical follow-up of 34 ± 19 months. The Florida sleeve occasionally
has been proposed as a method to treat acute Type A aortic dissection to avoid bleeding
and aortic valve replacement. The Florida Sleeve operation raises interest in the
treatment of Type A aortic dissection for multiple reasons: (1) it accomplishes aortic
valve sparing and annuloplasty; (2) there is no resection of the sinuses of Valsalva;
(3) no coronary artery ostial translocation is required; (4) En bloc resuspension
of the sinotubular junction to the outer graft is accomplished; (5) external protection
of dissected root tissues is achieved without need for reinforcement with Teflon's
strips and/or glue; and (6) the adequate sizing of the sinus graft, ensuring the preservation
of the functional aortic annulus, could prevent further development of valvular regurgitation.
In the setting of a dissected aortic root, bleeding can be prevented by avoiding suturing
through a weakened root wall and avoiding translocation of fragile, dissected coronary,
the coronary ostia especially when dissected could be delicate and cumbersome to reattach.
As suggested by the study of Heo et al,[7] the traditional supra commissural graft replacement could be complicated by progressive
deformation and dilatation of aortic root requiring surgery; reinforcement of the
sinuses of Valsalva, especially with regard to the noncoronary one, choosing an adequate
graft could prevents further complication, such as dilation or dissection.
After ascending replacement for Type A aortic dissection, over 70% of patients show
persistence of the distal false lumen in late follow-up, and further interventions
are frequently needed, either open or endovascular. In the study of Inoue et al,[3] unachieved primary entry resection and absence of total-arch replacement are independent
predictors of distal aortic dilatation (≥50 mm) at multivariable analysis.
Our simultaneous use of a frozen elephant trunk (Vascutek Thoraflex hybrid prosthesis)
provides many advantages: (1) it permits replacement of the entire aortic arch and
supraortic vessels; (2) it secures the isthmic zone, and (3) it creates a thoracic
landing zone suitable for subsequent endoprosthesis implantation.[8]
In this case report, two specific techniques were used to treat a Type A acute aortic
dissection, producing a total proximal aortic replacement. Many positive benefits,
including easier and quicker approach in an emergency, derive from the contemporaneous
use of these two surgical procedures.
There are many unsolved questions about this hybrid technique, especially for results
at long-term follow-up, and further studies are needed, but it could be an easier
choice in this peculiar, urgent setting.
