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Elephant stent aorta repair – good outcomes, but is it too complex?

Key clinical point: Total aortic arch replacement with implantation of an elephant-trunk stent avoids risks of other more conventional approaches.

Major finding: Among 20 patients who had the elephant-trunk procedure, 18 had good results at a mean of 26 months after the operation (one had thoracoabdominal aortic arch replacement at 9 months and one was lost to follow-up).

Data source: Retrospective review of 20 patients with acute type A dissection who had total arch replacement at a single center.

Disclosures: The study authors reported having no financial disclosures.

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Technique preserves key vessels

The Beijing study authors’ excellent postoperative outcomes show that alternative surgical techniques for elephant-trunk implantation can be employed safely, but their technique also raises questions about the use of advanced technology, Dr. Prashanth Vallabhajosyula and Dr. Wilson Y. Szeto of the University of Pennsylvania said in their commentary on the study (J. Thorac. Cardiovasc. Surg. 2015 [doi: 10.1016/j.jtcvs.2015.04.003]).

“But does this mean we should be doing [elephant-trunk] operation on every type A dissection patient?” wrote Dr. Vallabhajosyula and Dr. Szeto. If no primary tear appears in the aortic arch or the proximal descending thoracic aorta (DTA), “then should we empirically dissect the arch vessels and perform total arch replacement in an emergent situation?” They also questioned extensive dissection of the left subclavian artery (LSCA) by cutting into the muscles around the surgical site.

Elephant-trunk implantation is more complex than other aortic repair procedures, they noted. “So, if a total arch replacement is not required, then why do it?”

While they acknowledged advantages of total arch replacement, and elephant-trunk implantation in particular, most operations for type A dissection occur in smaller, community hospitals that are ill equipped to perform the procedure. “This raises the issue of wide clinical application of the [elephant-trunk] technique for acute type A dissection,” they said. The real issue may not be what type of anastomosis for the elephant-trunk technique surgeons should use, but rather what surgical technique – the elephant-trunk technique vs. transverse hemiarch reconstruction, they said. (Dr. Vallabhajosyula and Dr. Szeto mentioned that their institution has advocated for the latter.)

“To address this, a more comprehensive and meticulous approach is warranted based on parameters such as patient clinical picture, acuity, malperfusion, arch and DTA anatomy, and primary tear site location,” they said. But for now, Dr. Vallabhajosyula and Dr. Szeto said, the medical literature does not support total arch replacement over transverse hemiarch reconstruction.

Dr. Vallabhajosyula is assistant professor of surgery at the Hospital of the University of Pennsylvania; Dr. Szeto is associate professor of surgery in the division of cardiovascular surgery at the University of Pennsylvania Medical Center–Penn Presbyterian Medical Center.


 

FROM THE JOURNAL OF THORACIC AND CARDIOVASCULAR SURGERY

References

An acute aortic tear can be lethal, and more cardiac surgeons are favoring extended aortic arch replacement in these cases. Cardiac surgeons have tried many different arch replacement techniques, but en bloc repair and double- or triple-branch stent grafting carry significant risks, so a team of cardiac surgeons in Beijing has reported good 2-year results with a novel technique that combines stented elephant-trunk implantation with preservation of key vessels.

The technique accomplishes total arch replacement with the stent while preserving the autologous brachiocephalic vessels.

“This technique simplified hemostasis and anastomosis, reduced the size of the residual aortic patch wall, and preserved the autologous brachiocephalic vessels, yielding satisfactory surgical results,” wrote Dr. Li-Zhong Sun and colleagues at Beijing’s Capital Medical University (J. Thorac. Cardiovasc. Surg. 2015 [doi:10.1016/j.jtcvs.2015.03.002]).

There are four keys to the procedure:

• The use of forceps to grasp the stent-free sewing edge of the stented elephant trunk and straightening of the spiral shaped Dacron graft to approximately 3 cm.

• Preservation of the native brachiocephalic vessels.

• Creating a residual aortic wall containing the innominate artery and LCCA that’s as small as possible.

• An end-to-side anastomosis between the left subclavian artery (LSCA) and the left common carotid artery (LCCA), a key junction in their technique.

The 20 study subjects had surgery within 2 weeks of the onset of pain. All 20 were discharged after the procedure, and in a mean follow-up period of 26 months, 18 had good outcomes while 1 patient had thoracoabdominal aortic replacement 9 months after the initial surgery (1 patient was lost to follow-up).

The researchers used computed tomography to confirm patency of the anastomosis between the LSCA and LCCA.

In 2 of the 20 patients, the aorta was normal with aortic dissection limited to the descending aorta. In the remaining patients, the investigators observed thrombus obliteration of the false lumen around the surgical graft in 16, partial thrombosis in 1 and patency in 1.

The surgical technique exposes the right axillary artery through a right subclavicular incision and a median sternotomy, then dissects and exposes the brachiocephalic vessels and the transverse arch. Dissection of the LSCA and LCCA is the key step in making the end-to-end anastomosis between the two vessels. The researchers accomplished this by partially transecting the sternocleidomastoid muscle and other cervical muscles.

Dr. Sun and coauthors said that a separated graft technique offers a number of advantages over other techniques for aortic arch reconstruction. While en bloc repair preserves the native brachiocephalic vessels and, thus, results in long-term patency, the technique carries risk for postoperative rupture of the aortic patch containing the brachiocephalic vessels. Double- or triple-branched stent grafting has resulted in shifting or kinking of the graft and eventually graft occlusion or aortic disruption.

The authors acknowledged the study’s small sample size, and that the outcomes are “preliminary.” They said long-term follow-up would be required to confirm the outcomes.

They had no disclosures to report.

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