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Case Reports
NUMBER 3-4 YEAR 2011
Replacement of the Ascending Aorta and the Aortic Arch for Acute Type A Aortic Dissection
Clinic of Cardiovascular Surgery, Niculae Stancioiu Heart Institute, Cluj-Napoca

Correspondence to:
Dan Bindea, MD, Clinic of Cardiovascular Surgery, Niculae Stancioiu Heart Institute,
19-21 Motilor Str., Cluj-Napoca, Romania,
Tel. +40-264-591531
Email: bindea_dan_ch@yahoo.com
REZUMAT
Pacienta L.M. in varsta de 53 ani a fost internata de urgenta in Serviciul nostru cu diagnosticul de disectie de aorta (Ao) tip A cu interesarea portiunilor initiale a trunchiului arterial brahiocefalic (TABC) si a arterei carotide comune (ACC) stangi (confirmat prin CT in Spitalul teritorial). Ecografia cardiaca confirma diagnosticul si arata prezenta unei colectii pericardice cu semne de tamponada si a insuficientei aortice severe. În aceste conditii, pacienta este supusa de urgenta unei interventii chirurgicale complexe: protezarea valvei aortice, inlocuirea Ao ascendente si a 2/3 proximale din arcul aortic, reimplantarea arterelor coronare prin interpozitia a doua segmente de proteza scurte si reimplantarea TABC si a ACC stangi, de-asemenea prin intermediul unor segmente de proteza. Pentru refacerea portiunii initiale a aortei s-a utilizat procedeul Bentall si tehnica Mills. Pe perioada arestului cardiocirculator (53 min) perfuzia cerebrala a fost asigurata prin incanularea directa a TABC. Evolutia postoperatorie a fost marcata de prezenta unui sindrom de insuficienta respiratorie acuta (ARDS), care a necesitat ventilatia mecanica prelungita a pacientei. În ziua a 14-a postoperator a fost necesara evacuarea unei colectii pericardice compresive prin abord chirurgical subxifoidian. Ulterior, evolutia a fost fara alte evenimente. Consideram ca, chirurgia arcului aortic ramane o provocare pentru chirurgul cardiac; o tehnica chirurgicala excelenta alaturi de o protectie cerebrala buna asigura premisele unei reusite.

ABSTRACT
A 53-year old female patient was admitted in our Service for acute type A aortic dissection (confirmed on a CT scan made at a local hospital). The cardiac echography confirm the diagnostic and showed cardiac effusion with tamponade and severe aortic regurgitation. The patient underwent emergency surgery: replacement of the aortic valve, replacement of the ascending aorta and of the 2/3 of the aortic arch, associated with reconnection of the coronary arteries, the brachiocephalic trunk and the left common carotid artery to the aortic graft using also prosthetic grafts (For the replacement of the ascending aorta we performed Bentall procedure associated with Mills technique). During the cardio-circulatory arrest (53 min), the cerebral perfusion was made possible by cannulation of the brachiocephalic trunk. Surgery of the aortic arch remains a challenge for the cardiac surgeon. A good surgical technique together with a good cerebral perfusion assure the success of the surgical procedure.
INTRODUCTION

Acute type A aortic dissection, especially the one interesting the aortic arch, bears a high mortality (10-20%) and morbidity.1 The incidence of postoperative neurological complications remains high (5-70%) due to the advanced cerebral protection techniques: deep hypothermia with circulatory arrest, antegrade or retrograde cerebral perfusion.2-5
The structure of the aortic wall in the dissected area, the involvement of the coronary arteries, of the aortic arch and its branches represent technical difficulties that impose replacement of the ascending aorta and of the aortic arch, with reconnection of these branches to the aortic graft.
We are going to present the case of a female patient with type A aortic dissection involving the brachiocephalic trunk and the origin of the left common carotid artery, who underwent successful surgical correction.

CASE REPORT

Figure 1. CT Scan: type A aortic dissection.
A 53-year old female patient was admitted in our hospital with shock due to acute type A aortic dissection, diagnosed at a local hospital by CT scan.(Fig. 1)
Emergency cardiac echography revealed acute type A dissection that involved the aortic arch, the first 3 cm of the brachiocephalic trunk and of the left common carotid artery, severe aortic regurgitation and cardiac tamponade.
The patient was obese, diabetic and hypertensive.
An emergency operation was undertaken under general anesthesia and through a median sternotomy. Cardiopulmonary bypass was established via cannulation of the right femoral artery and of the right atrium and 500 ml of blood were evacuated from the pericardium; the aortic cross-clamp was applied and the dissected ascending aorta opened. The coronary ostia were also circumferentially dissected.
Giving the fact that the aortic root dissection involved also the coronary ostia and was associated with severe aortic regurgitation, Bentall reconstruction of the aorta was chosen (an intraoperatively-made composite valve graft conduct - mechanical 21 Carbomedics bileaflet valve and 26 Dacron graft was used), associated with reimplantation of the coronary arteries by interposing short 8 mm Dacron grafts (Mills technique).6
Using deep hypothermia (150C) and antegrade cerebral perfusion via direct cannulation of the brachiocephalic trunk (at a flow rate of 350-400 ml and a perfusion pressure of 60-70 mm Hg), the aortic arch was opened: an intimal tear was found at the origin of the brachiocephalic trunk, which extend on the 2/3 aortic arch and on the first 3 cm of the brachiocephalic trunk and the origin of the left common carotid artery.4,7 Therefore, the replacement of the aortic arch, up to the origin of the left subclavian artery was necessary (using the same 26 mm Dacron graft) and the distal anastomosis site was reinforced with Teflon felt strips using Prolene 3/0. The brachiocephalic trunk and the left common carotid artery were reconnected to the aortic graft using the interposition of 8 mm Dacron grafts. (Figs. 2,3)

Figure 2. Drawing showing the replacement of the aortic valve, replacement of the ascending aorta and of the 2/3 of the aortic arch, associated [...]
Figure 3. Intraoperative view showing the replacement of the aortic valve, replacement of the ascending aorta and of the 2/3 of the aortic arch [...]

Afterwards, the cardiopulmonary by-pass was reinstituted, the patient rewarmed, and the course of the operation was uneventful. The total extracorporeal circulation time was 4h 58 min, the aortic cross-clamp time was 2h 50min and the cardio-circulatory arrest time was 53 min.
Figure 4. Angio-CT at 3 months follow-up show no obstruction /stenosis of the grafts, and no dissection on the descending aorta.
Extubation was possible only during the 6th postoperative day, due to an acute respiratory distress syndrome (ARDS), without neurological deficit.
Postoperatively, on the 14th day, the patient required evacuation of a sero-sanguinolent pericardic effusion through a subxiphoidal incision. The postoperative course was uneventful and the patient was discharged 19 days after the main surgical procedure.
At the 3-month follow-up the angio CT scan shows no obstruction/stenosis of the grafts, and no dissection on the descending aorta; the patient remained free of symptoms. (Fig. 4)

DISCUSSIONS

Despite advances in operative techniques and postoperative care, repair of aortic dissection involving the aortic arch remains a challenging and high-risk procedure.
The success of the surgical intervention depends on a prompt and accurate diagnosis, emergency operation submission together with two extremely important surgical factors:
1. Correct evaluation of the lesion, removal of the entry point of the dissection and an aggressive replacement of as much dissected artery as possible; total arch replacement for acute type A aortic dissection may decrease the risk of late complications related to the false lumen and lead to excellent long term survival.8-11
2. Cerebral protection and a short circulatory arrest time (30-40 min); cerebral blood flow during the period of circulatory arrest may be delivered in either a retrograde or antegrade technique. The antegrade cerebral perfusion is considered more efficient and allows the surgeon a longer "safe" time to complete the anastomosis on the aortic arch.3,4,12
In our case we dealt with a complex lesion: ascending aortic dissection involving the proximal 2/3 of the aortic arch, the origin of the innominate artery, left common carotid artery, coronary ostia and severe aortic regurgitation. This lead to performing the Bentall procedure using the Mills technique: reimplantation of the coronary arteries by interposing short 8 mm Dacron grafts (this allowed for less anastomotic tension, and a more precise suture).
We had to prepare the valved tube together with its branches intraoperatively, due to lack of availability of ready-made prostheses for this type of pathology in our hospital. This has obviously prolonged the operative time.
Cerebral protection was ensured by direct cannulation of the innominate artery, distally to the dissection area, associated with profound hypothermia during the cardio-circulatory arrest. The efficiency of these methods was verified by cerebral transcranian pulse-oximetry, and by the presence of blood reflow in the left common carotid artery.

CONCLUSIONS

We chose to present this case in order to describe the successfully used technique for cerebral protection and due to the types of surgical techniques combined (Bentall procedure modified by Mills, aortic arch replacement with brachiocephalic trunk and left common carotid artery implantation using interposition grafts).
Although we resolved that case successfully, we must note that the operative mortality for acute aortic dissection in our hospital in 2010 remains high (around 37%).
REFERENCES

1. Reece TB, Green GR, Kron IL. Aortic dissection. In: LW Cohn. Cardiac Surgery in the Adult, Third edition, Ed. McGraw Hill Medical;2008:1195-1222.
2. Hagl C, Khaladj N, Krack M, et al. Hypothermic circulatory arrest during ascending and aortic arch surgery: the theoretical impact of different cerebral perfusion techniques and other methods of cerebral protection. Eur J Cardiothorac Surg 2003;24:371-378.
3. Okita Y, Minatoya K, Tagusari O, et al. Prospective comparative study of brain protection in total arch replacement: deep hypothermic circulatory arrest with retrograde cerebral perfusion or selective antegrade cerebral perfusion. Ann Thorac Surg 2001;72(1):72-9
4. Ueda Y, Miki S, Kusuhara K, et al. Deep hypothermic systemic circulatory arrest and continuous retrograde perfusion for surgery of aortic arch aneurysm. Eur J Cardio Thorac Surg 1992;6:36-41.
5. Bachet J, Teodori G, Goudout B, et al. Replacement of the transverse aoric arch during emergency operations for type A acute aortic dissection: report of 26 cases. J Thorac Cardiovasc Surg 1988;96:912-924.
6. Mills NL, Morgenstern DA, Gaudiani VA, Ordoyne F. "Legs" technique for management of widely separated coronary arteries during ascending aortic repair. Ann Thorac Surg 1996;61:869-873.
7. Guilmet D, Roux PM, Bachet J, et al. Nouvelle technique de protection cerebrale: Chirurgie de la crosse aortique. Presse Med 1986;15:1096-1098.
8. Ochiai Y, Imoto Y, Sakamoto M, et al. Long-term effectiveness of total arch replacement for type A aortic dissection. Ann Thorac Surg 2005;80:1297-1302.
9. Ando M, Nakajima N, Adachi S, et al. Simultaneous graft replacement of the ascending aorta and total aortic arch for type a aortic dissection. Ann Thorac Surg 1994;57:669-676.
10. Erwin M, Tan SH, Dossche KM, et al. Is extended arch replacement for acute type a aortic dissection an additional risk factor for mortality? Ann Thorac Surg 2003;76:1209-1214.
11. Estrera AL, Miller CC, Huynh TT, et al. Replacement of the ascending and transverse aortic arch: determinants of long-term survival. Ann Thorac Surg 2002;74:1038-1065.
12. Krahenbuhl ES, Immer FF, Stadler M, et al. Technical advances improved outcome in patients undergoing surgery of the ascending aorta and/or aortic arch: ten years experience. Eur J Cardio Thorac Surg 2008;34:595-599.


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