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The Aortic Uncrossing Procedure for Circumflex Aorta

      A “circumflex aorta” is a rare vascular ring caused by a right aortic arch with a left ligamentum arteriosum and a descending thoracic aorta that crosses posteriorly from right to left above the level of the tracheal carina (Fig. 1). The trachea and esophagus are compressed from the right aortic arch, the left ligamentum, and the posterior crossing aorta causing the typical symptoms of noisy breathing, dyspnea on exertion, dysphagia, and frequent upper respiratory tract infections. Although ligamentum division would divide the ring, that alone would not relieve the compression produced from this abnormal vascular anatomy. The aortic uncrossing procedure was first reported by Drs PlanchȨ and LaCoeur-Gayet

      Planche C, Lacour-Gayet F: Aortic uncrossing for compressive circumflex aorta: 3 cases. Presse Med 13:1331–1332, 1984 (Article in French)

      (Fig. 2). They also coined the term “circumflex aorta.” They performed the operation in 3 patients, all of whom had previously undergone ligamentum division and had persistent postoperative symptoms.
      • Robotin M.C.
      • Bruniaux J.
      • Serraf A.
      • et al.
      Unusual forms of tracheobronchial compression in infants with congenital heart disease.
      We now have experience with this operation in 4 patients.
      Figure thumbnail gr1
      Figure 1This computed tomography angiogram (CTA) demonstrates the posterior view of a 4.6-year-old child with a right cervical aortic arch, left ligamentum arteriosum, and retroesophageal left subclavian artery. The descending thoracic aorta crossing right to left posterior to the trachea and superior to the carina is clearly seen on this CTA. This posterior compression of the trachea is not relieved by ligamentum division.
      Figure thumbnail gr2
      Figure 2(A) This image illustrates the anatomy as exposed through a median sternotomy incision. The ascending aorta is on the right. The first brachiocephalic branch is the left carotid artery, the second branch is the right carotid artery, and the third branch is the right subclavian artery. The descending thoracic aorta crosses posterior to the trachea and esophagus and the left subclavian artery originates from the descending thoracic aorta adjacent to the ligamentum arteriosum. (B) The completed aortic uncrossing. The descending thoracic aorta has been brought anterior to the trachea and esophagus and anastomosed to the side of the ascending aorta. The ligamentum has been ligated and divided. The posterior compression of the trachea is now completely relieved. Ao = aorta; Pa = pulmonary artery.
      All vascular ring operations at our institution begin with a preoperative rigid bronchoscopy to assess for unsuspected additional tracheal pathology such as complete tracheal rings and to evaluate the extent and location of compression from the aorta.
      • Backer C.L.
      • Mavroudis C.
      • Rigsby C.K.
      • et al.
      Trends in vascular ring surgery.
      A circumflex aorta would have both right-sided compression from the right aortic arch as well as posterior compression produced from the circumflex descending aorta.
      The “aortic uncrossing” procedure is performed through a median sternotomy with cardiopulmonary bypass, hypothermia, and a short period of circulatory arrest (Figure 3, Figure 4, Figure 5, Figure 6, Figure 7, Figure 8, Figure 9, Figure 10, Figure 11, Figure 12, Figure 13). The heart is arrested with cardioplegia, head vessels are snared, and deep hypothermic circulatory arrest is established. The aorta is transected distal to the takeoff of the right subclavian artery and the proximal stump oversewn. The ligamentum arteriosum is ligated and divided. The right and left recurrent laryngeal nerves must be identified and preserved. The descending aorta is dissected from its posterior attachments and brought up on the left side of the ascending aorta. An arteriotomy is performed on the side of the ascending aorta adjacent to the left carotid artery. An anastomosis between the descending aorta and the arteriotomy is performed. The circulation is resumed and the patient is warmed and weaned from cardiopulmonary bypass. This procedure relieves both the posterior compression caused by the circumflex aorta and the right-sided compression of the trachea from the right aortic arch (Fig. 14).
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      Figure 3The heart and great vessels are exposed through a median sternotomy. The innominate vein is isolated and retracted cephalad. Ao = aorta; Pa = pulmonary artery; Svc = superior vena cava.
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      Figure 4Vessel loops have been placed around the great vessels for mobilization and snaring during a period of circulatory arrest. The ligamentum arteriosum is doubly ligated and divided.
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      Figure 5The plane between the ascending aorta and main pulmonary artery is dissected.
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      Figure 6Marking suture is placed on the left lateral side of the ascending aorta at the site of the proposed reimplantation. It is important to mark this site with the heart beating and full prior to the initiation of cardiopulmonary bypass. The left pulmonary artery is being retracted for exposure.
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      Figure 7Aortic uniatrial cannulation is performed and cardiopulmonary bypass is initiated with cooling to 18×C. During the cooling phase, further dissection of the right aortic arch is performed to delineate the site of aortic transection distal to the takeoff of the right subclavian artery. Great care is taken in the region of the right recurrent laryngeal nerve. The relationship of the left recurrent laryngeal nerve to the ligamentum is shown here. Ao = aorta.
      Figure thumbnail gr8
      Figure 8Once the patient's core temperature has reached 18×C, the aorta is cross-clamped and cardioplegic arrest is initiated. The head vessels are snared and circulatory arrest is begun. Dashed line marks the site of aortic transection.
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      Figure 9The aorta is transected distal to the right subclavian artery and the proximal end oversewn with running 5-0 prolene in 2 layers. Ao = aorta.
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      Figure 10The descending aorta is then dissected from its posterior attachments and brought up on the left side of the ascending aorta. Again, great care is taken in the region of the left recurrent laryngeal nerve. Dotted line shows site of arteriotomy for reimplantation.
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      Figure 11An arteriotomy is performed at the site of the previously placed marking sutures, this orifice mirrors the opening in the descending aorta.
      Figure thumbnail gr12
      Figure 12The path of the descending aorta is inspected to ensure there is no twist or irregularity and an anastomosis is performed with running 5-0 prolene sutures. The aorta is deaired with cold saline prior to securing the suture line.
      Figure thumbnail gr13
      Figure 13The ascending aorta is carefully deaired, the head vessels are unsnared, and the perfusion is resumed. The aortic cross clamp is released and the patient is rewarmed and weaned from cardiopulmonary bypass.
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      Figure 14The postoperative CTA shows the descending aorta and the transverse aortic arch are now anterior and to the left of the trachea. The anastomosis of the descending thoracic aorta to the transverse arch in this patient was widely patent and is off to the left of the trachea and is not compressing the trachea. Note: Adequate room must be left for the right pulmonary artery to traverse between the anterior portion of the trachea and the posterior aspect of the ascending aorta and transverse aortic arch. CTA, computed tomography angiogram.

      Results

      We have now performed this operation on 4 patients (age range, 18 months-5 years). Mean age was 3.6Ø1.7 years. Clinical details of these patients are shown in Table 1. All had preoperative imaging with computed tomography angiography (Fig. 1). Two patients had previous division of a small left aortic arch (1) and left ligamentum (2) through a left thoracotomy without improvement in their symptoms. The mean circulatory arrest time was 34Ø8 minutes. The mean cardiopulmonary bypass time was 98Ø19 minutes. There was no postoperative mortality or neurologic complications. Mean length of stay was 18Ø12 days (6, 6, 30, and 31 days). One patient required a temporary tracheostomy because of bilateral laryngeal nerve palsy, which recovered completely over a period of several months. All patients had a postoperative computed tomography angiogram demonstrating a patent arch and complete relief of posterior compression (Fig. 14). These patients may however have residual tracheomalacia that may take months to years to resolve. This is a major cardiovascular procedure, and is only indicated for a select group of patients with this precise anatomy. The key is to perform this operation (aortic uncrossing) rather than performing a prior left thoracotomy with ligamentum division because that procedure does not improve symptoms in patients with a circumflex aorta.
      Table 1Patients Undergoing Aortic Uncrossing for Circumflex Aorta
      Diagnosis
      (All had Circumflex Aorta)Age (y)Prior ProcedureCirculatory Arrest Time (min)CPB Time (min)Length of Stay (d)Complications
      1Double aortic arch, right arch dominant5.75Division of left aortic arch and left ligamentum (45 mo prior)358330Respiratory insufficiency requiring reintubation and mechanical ventilatory support (18 d)
      Left ligamentum arteriosumAortopexy (36 mo prior)
      Severe right-sided tracheomalacia
      Severe right bronchomalacia
      Apneic spells
      2Right cervical aortic arch2.58451316
      Left ligamentum arteriosum
      Retroesophageal left subclavian artery
      Coarctation of the posterior right arch
      Retro aortic innominate vein
      3Right aortic arch1.52Ligamentum division (11 months prior)28916
      Left ligamentum arteriosum
      Dysphagia
      Recurrent upper respiratory distress
      4Right cervical aortic arch4.65288731Postoperative temporary tracheostomy
      Left ligamentum arteriosumRight Horner Syndrome, bilateral recurrent laryngeal nerve paresis—both resolved
      Retroesophageal left subclavian artery
      Recurrent upper respiratory tract infectionsArrhythmia—sinus tachycardia
      Stridor
      Exercise intolerance
      Mean3.63Ø1.6734Ø8.0498Ø19.2618.25Ø12.26

      References

      1. Planche C, Lacour-Gayet F: Aortic uncrossing for compressive circumflex aorta: 3 cases. Presse Med 13:1331–1332, 1984 (Article in French)

        • Robotin M.C.
        • Bruniaux J.
        • Serraf A.
        • et al.
        Unusual forms of tracheobronchial compression in infants with congenital heart disease.
        J Thorac Cardiovasc Surg. 1996; 112: 415-423
        • Backer C.L.
        • Mavroudis C.
        • Rigsby C.K.
        • et al.
        Trends in vascular ring surgery.
        J Thorac Cardiovasc Surg. 2005; 129: 1339-1347