Keywords transapical - ascending aorta - CABG pseudoaneurysm
Introduction
Ascending aorta and aortic arch aneurysms still represent one of the most complex
conditions to be managed.
Open surgery is the gold standard in high risk patients; although surgical techniques
have improved considerably over time, the need for cardiac arrest and extracorporeal
circulation carries significant peri- and postoperative morbidity and mortality rates.
On the other hand, thoracic endovascular aortic repair (TEVAR) has evolved rapidly
as the standard treatment for lesions of the descending aorta, because of its high
technical success rate and low operative risk. Therefore, hybrid techniques with surgical
debranching of supra-aortic vessels followed by TEVAR are today a valid alternative
to open repair.[1 ]
Besides that, providing patients an endovascular treatment option for ascending aorta
is still complex and represent one of the last and biggest challenges of the endovascular
era. New trials are testing the role of endoprosthesis dedicated to ascending aorta
and aortic arch even if not yet available commercially.[2 ] At this time, endovascular solutions are applied only to compassionate cases in
need of urgent repair; therapeutic options are based on alternative adaptation of
available devices in a case-by-case fashion.
Technique and Results
The technique is demonstrated in a 63-year-old male, with dilatative cardiomyopathy
and a 32% ejection fraction, who underwent open chest surgery with prosthetic aortic
valve replacement (Magna Ease 23 mm, Edwards Lifesciences, Irvine, CA), mitral valve
repair (St. Jude Rigid Saddle 32 mm, St. Jude Medical, St. Paul, MN), and a double
coronary artery bypass grafting (CABG) (left internal mammary artery [LIMA] to D2
and great saphenous vein to D1) due to severe stenosis of the proximal tract of the
left anterior descending (LAD) coronary artery involving the origin of D1. LAD was
intraoperatively found to be intramyocardial and the operator decided to revascularize
D2. A 6-month follow-up, transthoracic echocardiogram demonstrated the presence of
an ascending aorta dilatation, subsequently confirmed by a computed tomography (CT)
angiogram ([Fig. 1 ]). In particular, a 73 × 70 mm saccular pseudoaneurysm of the ascending aorta at
the proximal anastomosis of the venous graft to D1 was detected.
Fig. 1 Preoperative computed tomography (CT) angiogram three-dimensional (3D) reconstruction;
arrow indicates the anastomotic pseudoaneurysm and the patent venous graft.
Because of the high surgical risk related to clinical and anatomical reasons, the
patient was deemed unsuitable for a redo open surgery and an endovascular solution
had to be considered. The site of the aortic lesion had a suitable landing zone above
the sinotubular junction of 25 mm in length and a landing zone before innominate artery
origin of 20 mm in length, with a homogeneous aortic diameter of 37 mm and a total
length to be covered of 100 mm. A single tube Gore Conformable Thoracic Aortic Graft
(TGE 45–45–10; WL Gore and Assoc. Inc., Flagstaff, AZ) was planned with a 20% oversizing.
Owing to the presence of an aortic prosthetic valve, a femoral access with the shaft
tip crossing valve leaflets in a retrograde fashion was to be avoided, and a transapical
approach through a mini left thoracotomy was considered. Moreover, one of the major
concerns was that the endovascular exclusion of the pseudoaneurysm would also cause
CABG occlusion with high risk for acute myocardial infarction. After multidisciplinary
discussion with interventional cardiologist, we decided for a preventive attempt of
percutaneous transluminal coronary angioplasty (PTCA) of the native LAD at its origin.
The patient accepted the therapeutic program proposed. He first underwent successful
PTCA of the origin of the native LAD; after 48 hours, endovascular exclusion of the
aortic pseudoaneurysm was attempted.
The technique was performed in a surgical hybrid suite, under general anesthesia,
in presence of vascular and cardiac surgeons. Through a left anterolateral mini-thoracotomy
along the fifth intercostal space, exposure of the left ventricular apex was obtained
in a standard fashion. The pericardial sac was opened, and a double purse-string suture,
reinforced with Teflon pledgets, was performed before apex puncture. We decided to
choose as puncture site an area slightly lateral and above the anatomical apex, where
the myocardial tissue seemed thicker. After preparation of the sutures, the patient
was heparinized with an activated clotting time goal of 300″. The left ventricle was
then punctured with a 19-G needle and access to the aorta obtained through a 24 F
Dryseal introducer (WL Gore and Assoc. Inc.) advanced over the prosthetic aortic valve,
to avoid any friction with the valve leaflets during maneuvers of introduction, positioning,
and removal of endograft devices. From a transfemoral venous access, a pacing wire
has been advanced into the right ventricle. As the proximal landing zone of the endograft
has been planned to be just proximally the innominate artery, a guidewire has been
inserted through an omeral access to identify its origin and eventually protect its
patency ([Fig. 2A ]).
Fig. 2 (A ) Angiogram showing the ascending aorta pseudoaneurysm and the positioning of a guidewire
from a right omeral access to identify the exact origin of the innominate artery from
the arch. (B ) Correct positioning of the endograft into the ascending aorta. (C ) Intraoperative final angiogram showing the exclusion of the ascending aorta pseudoaneurysm.
We advanced a guidewire into the ascending aorta under fluoroscopic guidance. Hereafter,
a Lunderquist extra-stiff guidewire (Cook Medical Inc., Bloomington, IN) was placed
and the endoprosthesis, a Gore C-TAG TGE45–45–10 (W. L. Gore and Associates, Flagstaff,
AZ), advanced in the ascending aorta. To guarantee a precise deployment and minimize
windsock effect, we deployed the endograft under rapid pacing stimulation and ventilation
with temporary arrest. At final intraoperatory angiography, the endograft appeared
well positioned, with complete exclusion of the pseudoaneurysm and patency of the
supra-aortic trunks ([Fig. 2B ] and [C ]). Hemostasis was achieved by tightening the purse-string sutures while removing
sheats from the left ventricle. A short period of rapid pacing stimulation during
suture tightening facilitated hemostasis, lowering systolic blood pressure. Finally,
pericardium was closed over the apex and a left lateral chest tube was placed before
wound closure in a standard fashion. The procedure was uneventful, and the overall
procedure time was 90 minutes. Postoperative period was free from complications, intensive
care unit stay was 1 day; a CT angiogram at 8 months demonstrated the complete exclusion
of the pseudoaneurysm ([Fig. 3 ]).
Fig. 3 Computed tomography angiogram three-dimensional (3D) reconstruction at 8 months after
endovascular repair.
Discussion
Saphenous vein graft pseudoaneurysm is a rare complication of CABG surgery and may
lead to life-threatening scenarios. The reported incidence in the literature is less
than 1%.[3 ] Because of the rarity of the disease there is lack of randomized trials and of standardized
treatment procedures.
These are often patients with several comorbidities and their exposure to high surgical
risks related to redo sternotomy, cardiac arrest with cardiopulmonary bypass is a
major issue.
An endovascular option, with exclusion of the ascending aorta CABG pseudoaneurysm,
may be a simple and valid alternative; however, several challenges have to be considered.
First of all, the available thoracic endograft in the market is designed for descending
aorta and has significant limitations when considered for use in a different site
such as the ascending aorta. In particular, in case of tall patients or extremely
tortuous aortic anatomies, the delivery system may be too short to allow deployment
in the ascending aorta from a standard femoral access. Another crucial point is that
often the endograft length is not adequate to fit with the ascending aorta. The length
of the ascending aorta from the sinotubular junction to the innominate artery varies
from 50 to 100 mm, with the majority of cases with a length between 60 and 70 mm.
On the other side, all the commercially available TEVAR devices have a minimum covered
length of 100 mm, or 77 mm considering also the proximal extension component.
Finally, the final tip of standard thoracic endograft is rigid and long, and not adequate
to cross multiple times the aortic valve, increasing the risk for severe traumatic
lesions of the ventricle and valve malfunctions.
To overcome all these limitations, some authors[2 ] already reported their preliminary experience in a small cohort (10 patients) with
a new dedicated ascending aorta device (Zenith AscendEndograft; William Cook Europe,
Bjaeverrskov, Denmark); unfortunately, this is still an investigational device.
Therefore, today the endovascular treatment of these rare cases is based on alternative
adaptation of off-the-shelf devices in a case-by-case fashion.
Different alternative access options for thoracic endograft have been reported by
some authors. Rayan et al[4 ] used a left axillary access, but in this case was to be avoided because of the risk
of temporary LIMA bypass occlusion.
Access from the cardiac apex through a mini thoracotomy is routinely performed in
any cardiac surgery center, where it is widely used for transcatheter aortic valve
implantation in patients with poor femoral access, and is recognized as a safe and
standardized access.[5 ]
To our knowledge, since the first description of a transapical access for the deployment
of a thoracic endograft in 2008 by MacDonald et al,[6 ] only few TEVAR are described with this access,[7 ] and only one is reported for the treatment of an anastomotic CABG pseudoaneurysm
of the ascending aorta.[8 ] However, it is not described yet in the literature a transapical deployment of an
endograft in patient with prosthetic aortic valve.
Conclusion
In conclusion, the use of a transapical access for the deployment of an ascending
thoracic aorta endograft seems safe and feasible also in case of prosthetic aortic
valve; it may be used to extend indications for aortic repair in selected patients
who are at high surgical risk and cannot wait for a custom endograft. A multidisciplinary
approach represents the key for adequate case planning and clinical success in these
rare and unusual pathologies.
