Type A Dissection Repair With Fenestrated Frozen Elephant Trunk

Background

Standard of care for acute type A dissection remains the “hemiarch” technique with an open distal anastomosis. This operation is currently favored because of its simplicity and reproducibility, as it is believed to carry a lower operative risk than more aggressive treatment of arch pathology. Data for this claim remains limited, and there remains a significant portion of patients who survive their initial hemiarch operation but who are left with complex aortic pathology which may require high-risk future intervention.

The question remains whether more aggressive treatment of aortic pathology up front at the time of a type A dissection is better both in the early phase as well as long term. Here, the author presents a video of a simplistic technique for a fenestrated frozen elephant trunk (FET), which allows for more aggressive treatment of the aortic arch at the time of type A dissection, as well as stabilization of the true lumen. The author believes this results in improved aortic remodeling, which should result in improved long-term results with no change in early mortality or complications. This technique was originally described by Roselli and colleagues [1]. It is a simple and effective way to treat more arch pathology up front with limited circulatory arrest time.

Operative Steps

Preoperative Evaluation and Planning

• Confirm normal arch anatomy, with particular attention to the origin of the vertebral artery.
• Preoperative measurements of the transverse and descending aorta, to confirm the size of frozen elephant trunk. Size one-to-one at most, never longer than a 100 mm stent.
• Preoperative measurements of the left subclavian artery, as well as the distance to the take-off of the left vertebral artery.
• Intraoperative transesophageal echocardiographic (TEE) evaluation of the aortic root and the extent of root pathology.

Cannulation and Bypass Setup

• Central cannulation is done using the Seldinger technique. True lumen cannulation is confirmed by TEE visualization of the descending aorta.
• Cooling to 28 degrees, as monitored by rectal and bladder temperatures.
• Retrograde and direct ostial del Nido cardioplegia are given.
• A 16F DLP vent placed in the right superior pulmonary vein.
• Circulatory arrest in steep Trendelenburg position.
• Direct cannulation of the true lumen of the innominate and left carotid arteries with flexible 16F retrograde cardioplegia cannulas, thus initiating selective antegrade cerebral perfusion at 8 -10 cc/kg/min with continuous cerebral oximetry monitoring.

Operation

• Following circulatory arrest, evaluate the aortic root pathology.
• Next, turn attention back to the arch and resect the aorta to the level of the innominate artery.
• Look specifically for large tears and ensure that the innominate and left carotid arteries do not have large tears at ostium. If they do, this may warrant a proper debranching of head vessels.
• Feed a single curve lunderquist wire into the true lumen of the descending aorta.
• Advance the stent into the thoracic aorta.
• Deploy the stent, favoring a slightly deep deployment.
• Use eye cautery to fenestrate the FET at the level of the left subclavian artery.
• Advance the left subclavian stent over a soft J-wire to the desired depth (based on preoperative measurements) and deploy it.
• Use a right-angle clamp to ensure the patency of the left subclavian stent. Confirm back-bleeding.
• Optional placement of several tacking horizontal mattress sutures on the superior third of the FET.
• Trim the collar of the hemiarch graft, and complete a standard hemiarch anastomosis being sure to include the inferior third of the stent graft in the anastomosis. Try to avoid placing stitches through stent struts.
• De-air the graft, clamp proximally, and resume full bypass flow and rewarming down the side-arm of the graft.
• Complete the proximal root operation as needed.
• De-air, reperfuse, wean from bypass, and complete hemostasis in the standard fashion.

Grafts Used

• FET: Medtronic (Dublin, Ireland) Valiant Thoracic Stent Graft
• Left Subclavian Stent: Gore (Newark, Delaware, USA) Viabahn
• Ascending Graft: Terumo (Tokyo, Japan) Sienna Gelweave Single Arm

References

1. Roselli E, Idrees J, Bakaeen F, et al. Evolution of simplified frozen elephant trunk repair for acute Debakey type I dissection: midterm outcomes. Ann Thorac Surg. 2018;105(3):749-755.

Dr Eudailey is a consultant for Medtronic and Terumo.