Department of Cardiothoracic Anesthesiology, Cleveland Clinic Foundation, Cleveland, Ohio
January 16, 2002.
Address correspondence and reprint requests to Emad Mossad, MD, The Cleveland Clinic Foundation, Department of Cardiothoracic Anesthesiology (G-3), 9500 Euclid Avenue, Cleveland, OH 44195. Address email to email@example.com.
Congenital abnormalities of the aortic arch can occur in association with anomalous origin of the right subclavian artery (ARSA) or left subclavian artery (ALSA). Kommerell’s diverticulum is a saccular aneurysmal dilation at the origin of an ARSA or ALSA (1), and can present with respiratory difficulty or dysphagia. Surgical repair is commonly done through a lateral thoracotomy, requiring single lung ventilation. We present a case of Kommerell’s diverticulum causing unexpected significant tracheal deviation and difficulty in lung separation with a review of a series of similar cases in our practice.
A 50-yr-old man presented to our hospital with a 1-yr history of progressive dysphagia and minimal dyspnea on exertion. Physical examination was nonspecific. Chest auscultation was normal with no rales and no vascular or precordial murmur. Chest radiography identified a right aortic arch with mild tracheal deviation to the left and clear lung fields (Fig. 1). Esophagogram showed extrinsic narrowing of the upper thoracic esophagus at the level of the right-sided aortic arch with temporary impediment to the passage of a 12.5-mm barium tablet. There was no evidence of stricture or ulceration in that region (Fig. 2).
Magnetic resonance imaging (MRI) showed a right aortic arch that was hypoplastic (mid-arch 2.2 cm). Arising from the anterior surface of the ascending aorta was the left common carotid artery followed by the right common carotid artery, the right subclavian artery, and the aberrant left subclavian artery that arose from a diverticulum of Kommerell. There was no evidence of complete vascular ring and no ligamentum was identified. This region of the aorta was enlarged to 3.7 cm, including both the main portions of the aorta and the diverticulum. The diverticulum was 2 cm in length and tapered to a normal-sized left subclavian artery. The descending aorta maintained a rightward anterior position relative to the spine and reached the midline position at the level of the diaphragm. There was displacement of the trachea and the esophagus to the left, but no significant narrowing of the airway was seen (Fig. 3).
A left thoracotomy, division of the diverticulum of Kommerell, and reimplantation of the left subclavian artery were planned.
After premedication with oral diazepam, the patient arrived to the operating room, where a peripheral IV was started, and standard monitoring applied. In a sitting position, the patient received a T4-5 thoracic epidural catheter for postoperative pain management. After induction with thiopental, fentanyl, and rocuronium, endotracheal intubation was attempted using a 37F left Mallinckrodt double-lumen endotracheal tube (DLT). On auscultation a marked decrease in breath sounds was noted through the right lung. Normal breath sounds were heard on the left lung when the tracheal connecting tube was clamped, but no breath sounds were heard on the right lung when the bronchial connecting tube was clamped and the right lung could not be ventilated. A 3.0-mm pediatric fiberoptic bronchoscope (FOB) was used to check placement of the tube. The FOB was inserted into the tracheal lumen but could not be introduced past the tube in order to visualize the carina. The FOB was then inserted into the bronchial lumen and the DLT was withdrawn up the trachea along with the FOB until the carina was visualized. The FOB was inserted into the left main bronchus and the DLT was forwarded over the FOB into the left main bronchus confirming proper positioning of the tube. Again, the right lung could not be ventilated. The same maneuver was repeated unsuccessfully with a smaller DLT. The tracheal deviation was believed to be unavoidably obstructing the tracheal lumen of the DLTs. Finally, the patient was reintubated with a standard 8.5-mm inner diameter endotracheal tube. A left main bronchus blockade was performed using a fiberoptically directed Arndt endobronchial blocker (BB) with a monofilament guide loop. Successful lung separation and bilateral ventilation was achieved. The surgical repair was done uneventfully through a left thoracotomy by reducing the size of the diverticulum, esophageal mobilization, and aortopexy.
The patient was transferred to the intensive care unit and successfully extubated 4 h later. Recovery was uneventful, notably without laryngeal edema or tracheal injury. He was discharged 4 days after the operation.
From 1994 to 2000, 13 patients underwent surgical correction of vascular rings with tracheoesophageal compression. The diagnoses included double aortic arch in 6 patients, right aortic arch with ALSA in 5 patients, and left aortic arch with ARSA in 2 patients. Kommerell’s diverticulum was present in 6 of these patients (Table). The most common presentation was dysphagia, with respiratory distress and stridor only in the smaller children. All patients underwent surgical repair through a lateral thoracotomy with lung separation using a DLT (in 4 patients) or a BB (in 2 patients), and all had a favorable postoperative course with a mean time to extubate of 2 hours, hospital length of stay of 5 days, and no mortality.
Kommerell’s diverticulum is a rare anomaly that occurs in association with a double aortic arch, a left aortic arch, and ARSA (0.5% of the population), or a right aortic arch with ALSA (0.1%) (2). Embryologically it represents the persistent distal end of the interrupted fourth aortic arch between the carotid and subclavian arteries (3).
Dysphagia of unclear etiology (dysphagia lusoria) is the most common presenting symptom of an enlarged anomalous subclavian artery and a Kommerell’s diverticulum (2). In the presence of a ligamentum arteriosum or a ductus between the subclavian artery and the pulmonary artery (as in small children), the vascular ring is complete and may compress the tracheobronchial tree, causing respiratory symptoms.
Diagnosis of this congenital vascular abnormality depends on clinical symptoms and several diagnostic modalities. Chest radiographs in 41 children with documented vascular rings were retrospectively reviewed and found to have an abnormality in 92% of the cases (4). Barium swallow with esophagogram and cardiac MRI are the most valuable diagnostic tests to demonstrate compression of the esophagus or the airway at the anticipated level of the aortic arch and the diverticulum. Aortography is only required if the precise vascular pattern needs further delineation (5). Although echocardiography may be used to establish the diagnosis, caution should be taken to avoid false diagnosis of aortic dissection or a mediastinal mass (6).
Kommerell’s diverticulum can compress the surrounding structures either directly, by aneurysmal dilation, or with age-related atherosclerotic changes (7). Once diagnosed, the diverticulum should be surgically resected regardless of size, for risk of rupture. Austin and Wolfe (8) reported 32 cases of aberrant subclavian artery with 20/32 having a Kommerell’s diverticulum. Rupture occurred in 6 patients (with two <5 cm in diameter) and was always fatal despite an emergent surgical attempt at repair.
The repair is commonly done through a left thoracotomy without cardiopulmonary bypass, thus necessitating lung separation. Although respiratory symptoms may be absent or minimal, as in our case, difficulty can be encountered during airway management. If a complete vascular ring is present, airway obstruction and collapse may occur with induction of anesthesia, and require positive pressure ventilation and attempts to bypass the site of obstruction by an endotracheal tube (ETT) or even a rigid bronchoscope (9). Separation of the lungs is preferably performed using a left-sided DLT for ease of insertion and positioning and the ability to suction and apply positive airway pressure to the operative lung during surgery. A right DLT is not preferred because of the risk of occluding the right upper lobe bronchus and the possibility of tracheal deviation by the diverticulum (10). If a DLT is difficult to position, as happened in our case, an attempt to use a single ETT with a BB that allows suctioning and oxygenation through an inner channel, as the Arndt blocker, should be used for lung separation.
In conclusion, we presented a series of patients with Kommerell’s diverticulum and a case demonstrating airway compromise and difficulty in lung separation. Alternative methods for one-lung ventilation should be available when managing this rare but potentially fatal congenital vascular anomaly.
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