Achalasia

Surgical treatment of recurrent achalasia includes esophagectomy with gastric pull-up. A MEDLINE search yielded no articles describing an adverse effect of this surgery on pulmonary function. We report the first case of acute ventilatory failure caused by gastric pull-up. An evaluation by flexible bronchoscopy, spirometry with flow-volume loops, and dynamic CT scanning revealed extrinsic compression of the trachea by the stomach causing obstruction. Endotracheal placement of a self-expanding stent resulted in the rapid extubation of the patient with normalization of the flow-volume loop and dramatic improvement in the FVC, FE[V.sub.1], and peak expiratory flow.

Key words: bronchoscopy; dynamic CT; esophagectomy; spirometry; stent; tracheal obstruction; tracheomalacia

Abbreviation: ETT = endotracheal tube

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The causes of benign upper airway obstruction are numerous. They include compression by bronchogenic cysts, thyroid goiter, and vascular structures, inflammatory diseases such as relapsing polychondritis and Wegener granulomatosis, postintubation tracheal stenosis, and tracheomalacia. Because of its position immediately posterior to the trachea, the esophagus also can contribute to upper airway obstruction. Megaesophagus secondary to advanced achalasia can cause acute tracheal obstruction. (1) There are, however, no reports describing an adverse effect of the surgical treatment of this disorder, esophagectomy with gastric pull-up, on pulmonary function. We report a case of tracheal compression by the stomach in a patient after such a procedure. Tracheal stent placement resulted in the successful extubation and discharge of the patient from the ICU.

CASE REPORT

A 58-year-old woman with a history of achalasia treated with laparoscopic transhiatal esophagectomy and cervical esophagogastrectomy presented to her primary physician with a 1-week history of somnolence and dyspnea worsened by eating. She was stridorous on examination and was referred to the emergency department. A direct laryngoscopy revealed no obstructive airway lesions, mobile vocal cords, and purulent secretions in the trachea and oropharynx. The examination was notable for a bulging neck mass, coarse breath sounds, and hypoxemia with an [O.sub.2] saturation of 88% while breathing room air. A chest radiograph revealed an abnormal gas density that projected over the mediastinum and extended into the neck, which was consistent with distention of the intrathoracic stomach. The lungs were otherwise clear. The patient was admitted to the hospital with a diagnosis of aspiration pneumonia.

The patient had dinner and later in the evening was noted to be somnolent and apneic. The measurement of arterial blood gases revealed the following: pH, 7.19; PC[O.sub.2], 88 mm Hg; and P[O.sub.2], 24 mm Hg. She was emergently intubated with a No. 7 endotracheal tube (ETT) and transferred to the ICU. A bronchoscopy, which was performed the next day, revealed no evidence of upper airway obstruction. The patient's arterial blood gas values had normalized, and she was breathing with minimal assistance from the mechanical ventilator and was extubated without incident. She experienced intermittent stridor over the next 2 days. Spirometry with flow-volume loops revealed severe obstruction with an FVC of 1.6 L (50% of predicted), an FE[V.sub.1] of 0.4 L (17% of predicted), and an FE[V.sub.1]/FVC ratio of 28. The peak flow was 0.7 L/s. The expiratory loop was flattened, suggesting an intrathoracic obstruction to airflow (Fig 1). Later that day, she experienced another respiratory arrest and was reintubated. Repeat bronchoscopy during careful withdrawal of the ETT revealed severe tracheal obstruction during expiration by structures anterior and posterior to the trachea. A chest CT scan was performed to delineate the cause of the extrinsic tracheal compression. The ETT was removed to facilitate the examination with an anesthesiologist in attendance. Following the insufflation of air into the intrathoracic stomach, a chest CT scan was performed during full inspiration, following complete exhalation, and while scanning was continuously performed at the level of maximal tracheal narrowing (without table increment) during an FVC maneuver. The inspiratory CT scan revealed that the trachea was compressed between the air-filled intrathoracic stomach and the innominate artery (Fig 2). CT scans obtained during the forced expiratory vital capacity maneuver revealed the dynamic nature of the tracheal obstruction. The tracheal diameter decreased from 8 mm during the inspiratory scan to 4 mm during the forced expiratory study (Fig 3). An upper GI study was performed to rule out gastric outlet obstruction. The gastric pull-up and intra-abdominal small intestine appeared normal in caliber without focal areas of narrowing or filling defects. There was normal emptying of contrast from the stomach into the small bowel. No anatomic obstruction was identified.

[FIGURES 1-3 OMITTED]

To alleviate the extraluminal compression of the trachea, a team consisting of a pulmonologist and an interventional radiologist deployed two 16 x 60-mm overlapping Wallstents under fluoroscopic guidance over the two areas of severest tracheal narrowing. After the stent placement, the trachea was visibly patent during bronchoscopy. The patient was extubated and transferred to the ICU for observation. Her dyspnea and stridor resolved, and she had no further episodes of respiratory compromise. Prior to discharge from the hospital, spirometry with flow-volume loop testing was repeated (Fig 1). Both the FVC and FE[V.sub.1] values had dramatically increased compared to those measured prior to the stent placement (FVC, 3.13 L [98% of predicted]; FE[V.sub.1], 1.96 L [77% of predicted]). Three months following hospital discharge, the patient underwent CT scanning with dynamic expiratory views. This revealed some granulation tissue within the diameter of the stent and no evidence of tracheal collapse (Fig 4).

[FIGURE 4 OMITTED]

Except for some mild mucus production, which was treated with an inhaler (Combivent; Boehringer Ingelheim; Ridgefield, CT), the patient has had no complications arising from stent placement. She remains well 18 months after undergoing the procedure.

DISCUSSION

This case demonstrates the value of employing a multimodal approach in the evaluation of benign airway obstruction involving bronchoscopy, dynamic CT scanning, and pulmonary function testing. The initial flexible fiberoptic bronchoscopy that was performed with an ETT in place revealed no obvious cause for upper airway obstruction. But because the expiratory flow-volume loop suggested intrathoracic airway obstruction, bronchoscopy was repeated while the ETT was carefully removed. This revealed severe tracheal obstruction during expiration by structures anterior and posterior to the trachea. CT images captured during dynamic expiration identified these structures as the innominate artery and stomach, respectively. The trachea narrowed to 4 mm at this point, which is approximately the diameter of the critical orifice predicted by the expiratory flow-volume loop and is much smaller than the mean anteroposterior diameter of the normal trachea during the forced expiration observed with dynamic CT scanning. (2) After stent placement, the following were observed: (1) the trachea remained patent during bronchoscopic endotracheal examination; (2) a CT scan with dynamic expiratory views revealed no evidence of tracheal compression; and (3) FE[V.sub.1] values improved from 0.45 to 1.96 L with no evidence of flattening of the expiratory flow-volume loop.

Dynamic CT scanning in this patient demonstrated tracheal compression by the innominate artery anteriorly, and by the stomach posteriorly. Compression of the trachea by vascular structures has been best described in the pediatric literature. In a review of 46 cases of esophageal atresia repair in children, 12 developed severe airway problems that were manifested mainly by acute apneic episodes. (3) These were related to compression by the innominate artery alone in eight patients, and in combination with the aortic arch in four patients. The dilated esophagus may compress the trachea posteriorly in this disorder. Upper airway obstruction caused by esophageal dilatation is also a rare, but potentially fatal, complication of achalasia, a motility disorder characterized by aperistalsis of the esophageal body and a hypertonic lower esophageal sphincter. (4) Although uncommon, achalasia is also sometimes associated with gastroduodenal motility disorders. (5) The initial surgical treatment for achalasia includes a Heller myotomy, a combined myotomy with antireflux procedure, or an antireflux procedure alone. Esophageal resection is accepted as a reoperative procedure for recurrent symptoms or for treatment complications of achalasia. In this surgical approach, anastomosis of the upper esophagus usually is established with the stomach at the cervical or intrathoracic level. Some degree of gastric distention is very common in patients with gastric pull-up. Our patient may have experienced gastric dilatation from gastroparesis associated with achalasia and from the gastric pull-up procedure itself. Similar to a child who develops tracheomalacia in association with esophageal atresia, our patient may have developed an abnormally compliant trachea from continuous extrinsic compression by a dilated esophagus, then gastric pull-up, over many years.

For airway obstruction due to extraluminal compression, the only endoscopic treatment, aside from dilation with a rigid bronchoscope, is the placement of stents or endoprostheses. Several studies (6,7) have demonstrated the utility of tracheal and bronchial stents for benign airway obstruction. These wire stents are desirable because they can be incorporated into tissue with less bronchial obstruction and mucus plugging than silicone stents. However, there are problems with their use. These include excessive granulation, hemorrhage, malposition, migration, perforation, and unraveling. In a small study (8) of four patients with tracheal stents, main bronchial stents, or both, all three patients with tracheal stents required their removal for stent-related complications within the first 6 months. The authors of this study suggested that the malacic trachea with its associated variation in shape and diameter during the respiratory cycle may adversely affect the longevity of expandable metal stents. However, growing experience has shown that metal stents, such as the Wallstent, are easy to deploy with adequate radial force, flexibility, and dynamic expansiveness to accommodate the trachea.

This case expands the differential diagnosis of tracheal obstruction in patients who have undergone the gastric pull-up procedure. In addition, it emphasizes both the benefit of a multimodal approach, including bronchoscopy, dynamic CT scanning, and measurements of airway physiology, in documenting upper airway obstruction and the utility of expandable metal stents as an alternative to surgery.

REFERENCES

(1) Berrisford RG, Oo A, Walshaw MJ, et al. Tracheal obstruction in achalasia: a role for airway stenting? Ann Thorac Surg 1998; 66:939-941

(2) Stern EJ, Graham CM, Webb WR, et al. Normal trachea during forced expiration: dynamic CT measurements. Radiology 1993; 187:27-31

(3) Triglia JM, Guys JM, Borrione CL. Tracheomalacia caused by arterial compression in esophageal atresia. Ann Otol Rhinol Laryngol 1994; 103:516-521

(4) Requena R, Hart AK, Kuhn JJ. Acute upper airway obstruction in achalasia. Otolaryngol Head Neck Surg 1999; 120: 105-108

(5) Eldeer JR, Gillespie G. The vagus and achalasia. Gut 1969; 10:1045-1046

(6) Eisner MD, Gordon RL, Webb WR, et al. Pulmonary function improves after expandable stent placement for benign airway obstruction. Chest 1999; 115:1006-1011

(7) Vergnon J-M, Costes F, Bayon MC, et al. Efficacy of tracheal and bronchial stent placement on respiratory functional tests. Chest 1995; 107:741-746

(8) Hramiec JE, Haasler GB. Tracheal wire stent complications in malacia: implications of position and design. Ann Thorac Surg 1997; 63:209-213

* From the Departments of Medicine (Drs. Kim and Golden) and Radiology (Drs. Gotway and Webb), Division of Pulmonary and Critical Care Medicine, and the Section of Interventional Radiology (Dr. Gordon), University of California, San Francisco, CA.

Manuscript received May 16, 2001; revision accepted August 21, 2001.

Correspondence to: Jeffrey A. Golden, MD, Division of Pulmonary and Critical Care Medicine, University of California, San Francisco, 400 Parnassus Ave, Box 0359, San Francisco, CA 94143-0359; e-mail: jgolden@itsa.ucsf.edu

COPYRIGHT 2002 American College of Chest Physicians
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