Arch-First Technique Used with Commercial T-Graft

Abstract

Staged repair of extensive thoracic aortic aneurysms puts certain patients at risk of rupture. We report the case of a patient with Marfan syndrome who presented with subacute type-A aortic dissection and a large descending aortic aneurysm. We used the arch-first technique with a commercially available Dacron T-graft. A clamshell incision was used for exposure. A button of arch vessels was anastomosed to the T-graft. Antegrade cerebral perfusion was established through the side branch. The distal end of the graft was anastomosed to the descending aorta and the proximal end to a composite graft. The duration of cerebral ischemia was 30 minutes; antegrade cerebral perfusion lasted 52 minutes. The patient experienced no neurologic dysfunction and was discharged with no major deficit. This technique shortens brain-ischemia time and is a good option if the risk of rupture of the descending component of an extensive thoracic aortic aneurysm is high.

To the best of our knowledge, this is the 1st reported case in which the arch-first technique has been used with a commercially available T-graft to treat subacute type-A aortic dissection in a patient with Marfan syndrome. (Tex Heart Inst J 2002;29:26–9)

Different strategies and approaches have been used to treat extensive thoracic aneurysms. Staged repair has been used with varying rates of success. ^1–3 Crawford and associates ⁴ reported a late or combined mortality rate of 21% after completion of the 2-stage procedure. Single-stage replacement has been preferred in certain situations, such as extensive involvement of the arch or impending rupture of the descending component of a thoracic aortic aneurysm. ^5–7 During traditional single-stage replacement of the thoracic aorta, both distal (lower descending aorta) and proximal (arch) anastomoses are performed under hypothermic circulatory arrest. ^6–8 The arch-first technique, which modifies the perfusion strategy in order to minimize the period of brain ischemia, was introduced by Rokkas and Kouchoukos ⁹ in a group of non-Marfan patients. In their technique, they 1st constructed the arch anastomosis with a custom-made Dacron T-graft and perfused the brain with cold blood through the side branch of the graft while performing reconstruction of the descending thoracic aorta.

To the best of our knowledge, ours is the 1st reported case in which the arch-first technique has been used with a commercially available T-graft to treat subacute type-A aortic dissection in a patient with Marfan syndrome.

Case Report

In February 2001, a 35-year-old woman was admitted to the hospital with a 20-day experience of severe chest and back pain. Remarkable findings on physical examination were the stigmata of Marfan syndrome and a murmur heard both in systole and in diastole, most audibly over the left border of the sternum. Electrocardiography revealed sinus rhythm and left ventricular hypertrophy. Chest radiography showed a large upper-mediastinal mass extending into the left pleural cavity. Transthoracic echocardiography revealed 3+ aortic insufficiency, annuloaortic ectasia, a flap in the ascending aorta, and good left ventricular function. Computed tomography of the chest and abdomen confirmed the diagnosis, which was type-A dissection, and showed that the diameters of the proximal ascending aorta and the proximal descending saccular aneurysm were 7 cm and 9 cm, respectively (Fig. 1). We decided to replace the entire thoracic aorta in a single stage for 2 reasons: the risk of rupture of a large descending thoracic aortic aneurysm was considered to be high in a patient with Marfan syndrome; ¹⁰ and there might be no suitable neck of aorta with which to perform an elephant-trunk procedure.

Fig. 1 Computed tomography shows A) ascending aortic aneurysm and dissection with the intimal flap and B) descending aortic aneurysm.

Surgical Technique

The technique was similar to that described by Rokkas and Kouchoukos. ⁹ We cannulated both radial arteries and placed a jugular venous bulb catheter and a pulmonary artery catheter. Electroencephalographic monitoring was used. We intubated the patient in supine position, then rotated her 30° toward the right by placing towels under the left scapula.

A clamshell incision (bilateral anterior thoracotomy and transverse sternotomy) was used for exposure of the heart and the entire thoracic aorta. Dense adhesions in the left pleural cavity were released for better exposure of the distal descending aorta. The left phrenic nerve was freed from the aorta and protected. The left vagal nerve had to be sacrificed.

After systemic heparinization, cardiopulmonary bypass was established with femoral arterial and 2-stage right atrial cannulation. Despite slow induction of the perfusion, malperfusion of the brachiocephalic vessels was observed after cross-clamping of the ascending aorta. During a brief period of circulatory arrest, we removed the femoral artery cannula and rapidly inserted it into the true lumen of the completely transected ascending aorta, securing it with umbilical tape. Blood cardioplegic solution was administered directly through the coronary ostia. Retrograde infusion was not performed because of a persistent left superior vena cava, which also had been freed from the aneurysm. The left ventricle was vented through the right superior pulmonary vein.

While the patient was being cooled to a rectal temperature of 18 °C, the ascending aorta was explored. There was a flap down to the annulus, but no tear. Button modification of the Bentall technique was performed to enable replacement of the dilated and dissected aortic root with a 26-mm Meadox® Hema-shield® woven double velour graft containing a 23-mm bileaflet mechanical valve (St. Jude Medical, Inc.; St. Paul, Minn). The patient was cooled down further to 15 °C, and an oxygen saturation level of more than 95% was attained in the internal jugular vein. After circulatory arrest, a cuff of aortic tissue containing the arch vessels was prepared. An opening was made on the commercially available Dacron T-graft (Vascutek® Gelweave® 24/8 mm–40/15 cm; Renfrewshire, Scotland) opposite the site of insertion of the side branch, and an anastomosis to the arch vessels was performed (Fig. 2A). All aortic anastomoses were constructed with continuous 3–0 polypropylene suture, buttressed with a strip of Teflon felt. Retrograde cerebral perfusion at a flow of 600 mL/min was begun to evacuate the air from the brachiocephalic arteries. A straight cannula was inserted into the branch graft. After evacuation of the air and clamping of the distal and proximal ends of the graft, cold antegrade cerebral perfusion was established at 800 to 1200 mL/min to maintain a radial artery pressure of 50 mmHg. The descending aorta was incised distal to the arch, and the distal limb of the graft was passed down through the opening under the pedicle containing the phrenic nerve and the left superior vena cava. The origin of the tear was in the proximal descending aortic aneurysm. We fenestrated the multichannel distal descending aorta and anastomosed the distal limb of the graft to it with an open technique (Fig. 2B). The distal clamp was removed and warming was begun. The intercostal and bronchial arteries were ligated. The proximal end of the aortic graft was sutured end-to-end to the composite graft (Fig. 2C). After de-airing, the patient was weaned from cardiopulmonary bypass with some inotropic support. The side branch of the graft was divided and the suture ligated close to the main graft. The duration of cerebral ischemia was 30 minutes; of antegrade cerebral perfusion, 52 minutes; and of pump time, 290 minutes.

Fig. 2 Steps in the aortic replacement: A) anastomosis of arch button to the opening on the T-graft, B) construction of the distal anastomosis during antegrade selective cerebral perfusion, and C) graft-to-graft anastomosis while warming.

Results

The patient awoke 12 hours after the operation but could not be extubated until the 2nd postoperative day due to borderline oxygenation. The postoperative blood loss was 600 mL. Histopathologic examination of the aortic valve was consistent with myxomatous degeneration. The patient did not have any permanent or temporary neurologic dysfunction (the latter has been reported to be a functional manifestation of subtle brain injury ¹¹). Postoperative digital subtraction angiography showed a satisfactory repair (Fig. 3). The patient was discharged without sequelae other than left vocal cord paralysis and has not had any additional problems within a follow-up period of 1 year. Her voice is much improved after speech therapy.

Fig. 3 Postoperative digital subtraction angiogram shows a satisfactory repair.

Discussion

The clamshell incision, which provides excellent exposure of the heart and the entire thoracic aorta, has been used for single-stage replacement of the thoracic aorta with an operative risk comparable to that of the 2-stage approach. ⁷ The clamshell incision was well tolerated by our patient and it was cosmetically acceptable.

The technique of perfusing the cephalic vessels via a separate graft has been described by Ergin and associates. ¹² The arch-first technique follows a similar strategy and minimizes brain-ischemia time by providing uninterrupted antegrade brain perfusion. ⁹ Rokkas and Kouchoukos ⁹ reported 1 death among 10 patients (6 initial and 4 additional), which was a better mortality rate than those reported by investigators who did not use the arch-first technique in performing extensive single-stage resection of the thoracic aorta. ^6,7 None of the patients of Rokkas and Kouchoukos ⁹ had Marfan syndrome or acute or subacute type-A dissection. These same investigators, incidentally, have since reported successful application of the arch-first technique to single-stage reoperative repair of chronic type-A aortic dissection. ¹³

The reason for replacing the entire thoracic aorta in this patient, from the aortic valve annulus to the level of the diaphragm, was the coexistence of subacute type-A dissection, annuloaortic ectasia, and a large descending aortic aneurysm. The arch-first technique with clamshell incision is a good option for patients with Marfan syndrome and subacute type-A dissection when total thoracic aortic replacement is indicated. A commercially available T-graft can be used for this purpose.