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CARDIOVASCULAR ANESTHESIOLOGY

Elephant Trunk Prosthesis Kinking: Transesophageal Echocardiography Diagnosis

Florent Wallet, MD^*, Sébastien Perbet, MD^*, Marie-Hélène Fléron, MD^*, Victor De Castro, MD^*, Gilles Godet, MD^*, Michèle Bertrand, MD^*, Edouard Kieffer, MD, Pierre Coriat, MD^*, and Jean-Pierre Goarin, MD^*

From the Departments of *Anesthesiology and Critical Care, and Vascular Surgery, Pitié-Salpêtrière University Hospital, Assistance Publique-Hôpitaux de Paris, Paris, France.

Address correspondence and reprint requests to Dr. Marie-Hélène Fléron, Département d’Anesthésie-réanimation, CHU Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, 47-83 boulevard de l’Hôpital, 75013 Paris Cedex 13, France. Address e-mail to mh.fleron{at}psl.aphp.fr.

A patient underwent aortic arch replacement by the elephant trunk technique as the first part of treatment of a Stanford type A aortic dissection with retrograde extension into the aortic arch. The aortic arch was approached through a median sternotomy and was replaced because of extended dissection to left subclavian artery. Cardiopulmonary bypass (123 min) and deep hypothermic circulatory arrest at 18°C (34 min) allowed both anastomosis of the elephant trunk and cerebral protection. An intimal tear was clearly identified 50 mm after the origin of left subclavian artery. The proximal end of a 22-mm aortic prosthesis (Polythese®, LPI France) was sutured to the ascending aorta 10 mm distal to the sinotubular junction. Then, the innominate and left common carotid arteries were implanted directly onto the graft. The left subclavian artery was transposed onto the left common carotid artery. The length of the inserted prosthesis was 150 mm. A large portion of intimal flap was resected as far as possible into the aorta (leaving at least 1 cm on both sides of the membrane to avoid injury to the aorta) to allow insertion of the distal part of the prosthesis. The final result of the procedure is described on Figure 1. After placement of several clips to facilitate radiologic visualization, the distal end of the prosthesis was introduced and left free in the descending thoracic aorta.

View larger version (38K): [in this window] [in a new window]   Figure 1. Schematic drawings showing the main steps of the elephant trunk vascular prosthesis procedure.

A major enlargement of the mediastinum appeared 28 days after surgery on chest radiograph with the upside-down position of metallic clips marking the distal part of the aortic prosthesis. A pressure gradient between the arm and leg was then noted (125/65 and 85/45, respectively) 28 days after surgery. Our patient’s clinical examination was normal and there was no sign of organ failure. A transesophageal echocardiography (TEE) examination was then performed showing on a descending aorta short-axis view (desc aorta SAX) a double-lumen aspect of the distal part of the prosthesis. A descending aorta long-axis view revealed a complete kinking of the prosthesis with the distal end in cephalad direction (Fig. 2). A high velocity (yellow) and turbulent color Doppler flow pattern (mosaic) was noted at the kinking level and at the distal end of the prosthesis (please see video loop at www.anesthesia-analgesia.org). Further TEE examination showed that the prosthesis was positioned inside the false lumen without intimal membrane in the initial part of descending aorta. Swirling echo reflections indicative of low flow were noted in the false lumen. Complete examination of the descending aorta revealed that the intimal membrane was preserved in the distal part of the aneurysm with false and true lumens. A mural thrombus partially occluding the false lumen of the dilated aneurysm was also found. Because of the impending risk of rupture, the second stage of the surgical procedure was anticipated and performed 28 days after the first stage. Resection of the distal intimal membrane and anastomosis of a second prosthesis were performed. Postoperative follow-up was uneventful and the patient was discharged 10 days later.

View larger version (22K): [in this window] [in a new window]   Figure 2. Composite two-dimensional proximal descending aortic short-axis view at a multiplane angle of 0 and 90° showing the complete kinking of the prosthesis with two circular lumens in the short-axis view at a multiplane angle of 0.

The elephant trunk technique consists of leaving a piece of tube graft floating in the descending aorta1 for the second stage of aortic replacement2,3 (Fig. 1).

The major therapeutic impact of TEE monitoring is recognized for cardiac surgery. This should be extended to major aortic surgery. Exhaustive and close TEE examination should be part of routine procedures for cardiovascular anesthesiologists, especially for complex aortic surgeries.

In this rare surgical procedure, it is of major importance to check that the graft is adequately positioned in the descending aorta. TEE examination of the descending thoracic aorta is accomplished by turning the transducer to the left from the midesophageal four-chamber view until the aorta is located in the center of the screen. This is the desc aortic SAX view. Normal TEE aspect of an elephant trunk is one single circular prosthesis inside the descending thoracic aorta on a desc aortic SAX. A rotation of the multiplane angle from 0 to 90°, providing a scan of the descending thoracic aorta, should then be performed. During scanning, we first see a single circular prosthesis inside the native descending thoracic aorta on the desc aortic SAX and after rotation of the probe, the prosthesis is seen as two parallel lines inside the aorta. The position of the distal part of the graft should be checked at the end of the surgical procedure, because of possible aberrant placement of the prosthesis. Normal aspect is a floating graft in the native aorta. Normal aspect should be confirmed by a Doppler examination, showing a normal laminar Doppler color flow imaging from the distal end of the prosthesis.

In case of aortic dissection, it is also important to clearly discriminate false and true lumen on TEE imaging in order to check the correct location of the aortic prosthesis with perfusion of the true and false lumens after resection of the intimal membrane. It is also generally impossible to place the elephant trunk in the true lumen because of compression by the false lumen, poor elasticity due to fibrosis of the intimal membrane, risk of exclusion of the left renal artery and, sometimes, the arteries supplying the spine. TEE allows perfect location of the distal part of the elephant trunk in the descending aorta after surgical control. The distal ascending aorta and proximal aortic arch could not be visualized because of an air-filled trachea interposition.

Footnotes

Accepted for publication September 19, 2007.

REFERENCES

1. Borst HG, Walterbusch G, Schaps D. Extensive aortic replacement using "elephant trunk" prosthesis. Thorac Cardiovasc Surg 1983;31:37–40[Web of Science][Medline]
2. Heinemann MK, Buehner B, Jurmann MJ, Borst HG. Use of the "elephant trunk technique" in aortic surgery. Ann Thorac Surg 1995;60:2–7[Abstract/Free Full Text]
3. Svensson LG, Kim KH, Blackstone EH, Alster JM, McCarthy PM, Greenberg RK, Sabik JF, D’Agostino RS, Lytle BW, Cosgrove DM. Elephant trunk procedure: newer indications and uses. Ann Thorac Surg 2004;78:109–16[Abstract/Free Full Text]

This Article Full Text (PDF) CME: Take the course for this article: Echocardiography Rounds Echo Loops Alert me when this article is cited Alert me if a correction is posted Services Email this article to a colleague Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Wallet, F. Articles by Goarin, J.-P. Search for Related Content PubMed PubMed Citation Articles by Wallet, F. Articles by Goarin, J.-P. Related Collections Cardiovascular Monitoring (Cardiac) Echo Rounds Video Clip