Page 448 - Read Online

Page 2 of 8 Yamanaka et al. Vessel Plus 2020;4:39 I http://dx.doi.org/10.20517/2574-1209.2020.46

INTRODUCTION
The frozen elephant trunk (FET) technique was initially developed in 1994 as one of the first types of
[1]
hybrid surgery to combine endovascular treatment and open surgery and has since been disseminated
worldwide. This technique has been widely adopted as a single-stage open aortic repair technique for
[2]
non- dissecting arch aneurysm with a downstream extension or a first-stage procedure , followed by a
second open repair or thoracic endovascular aortic repair. In cases of acute or chronic aortic dissection,
this technique is a useful additional total aortic arch replacement (TAR) procedure; in such cases, FET is
[3]
used to reinforce the distal anastomosis of the TAR and close the false lumen of the descending aorta . In
Japan, handmade FET device had been used in some hospitals since 1994. The first commercial product (JG
open stent) was introduced in 2014 and modified to Frozenix in 2017. Although this graft has been widely
used with concomitant TAR in Japan, the indication for non-dissecting distal aortic arch aneurysm is still
[4]
controversial . We studied the outcomes of TAR by the use of the FET technique for distal aortic arch
aneurysms.

METHODS
Between August 2014 and February 2020, 40 patients underwent TAR for distal aortic arch aneurysms
using the FET technique at Tenri Hospital and Nara Prefecture General Medical Center. Informed consent
was obtained from all patients on their information. We have followed up all patients until June 2020.
The preoperative patient characteristics are listed in Table 1. The age at surgery was 77.0 ± 6.0 years (16
octogenarians, range 59-87 years), and the number of males was 35 (87.5%). The number of fusiform distal
aneurysm was over half. The rate of saccular type aneurysm and the extension of aneurysm was 35% and
10%. Surgical indication of fusiform distal aneurysm is more than 55mm of diameter. But the indication of
saccular type aneurysm depends on configuration, diameter and enlargement rate. Preoperative comorbid
diseases were hypertension in 32 patients (80.0%), dyslipidemia in 16 (34.7%), chronic obstructive
pulmonary disease in 13 (32.5%), coronary artery disease in 10 (25.0%), stroke in 9 (22.5%), diabetes
mellitus in 9 (22.5%) and chronic renal dysfunction, (defined serum creatinine ≥ 1.2 mg/dL, in 10 patients
(25%). Six patients of them (15%) had aortic surgery previously.

FET selection
We used Frozenix (or JG Open Stent) in all cases. The available sizes of Frozenix as follows, the diameter of
Frozenix: 21, 23, 25, 27, 29, 31, 33, 35, 37, 39 mm. The length of stented graft: 6, 9, 12 cm. The optimal FET
was selected with use of preoperative computed tomography. The length of FET was decided by measuring
the distance between the site of aortic resection and the intended location of the descending aorta. We
rarely use the unstented part of FET and therefore removed all but 1 cm of the unstented part to prevent
graft kinking. In other word, the distance from the distal end of FET should be no more than the stented
part + 1 cm. The diameter of FET was approximately 10% greater than the diameter of the descending aorta
at the planned location of attachment.

Operative procedure
The operation was performed through median sternotomy. We used 2 main arterial cannulation sites; the
ascending aorta in most of patients and the axillary artery in the shaggy aorta. Venous cannula was inserted
into right atrium. Subsequently, the total extracorporeal circulation was initiated. After cooling to achieve
a bladder temperature of 25 °C, the ascending aorta was cross-clamped, and cold blood cardioplegia was
infused to the aortic root. After circulatory arrest, the proximal left subclavian artery was ligated, and we
started cerebral perfusion (200 mL/min) via an 8-mm graft anastomosed to the left axially artery. After aortic
arch incision, selective cerebral perfusion was established from the brachiocephalic artery (400 mL/min)
and the left common carotid artery (200 mL/min). Total cerebral perfusion was 800 mL/min and was
performed by one roller pump . We closely monitor near infrared spectroscopy and artery pressure in
[5]