Aortic coarctation

A 33-year-old white man was at his work as an auto mechanic when leaning over a car engine, he had the sudden onset of cough and produced a mouthful of blood with the first tussive effort. He subsequently expectorated a "basin-full" of blood. At a local emergency room he was found to be moderately hypotensive with a hemoglobin of 15.0 g/dl and a hematocrit value of 43.5 percent. He received one unit of packed red blood cells and was transferred to our facility. His hemoptysis stopped spontaneously and on presentation to our institution, he was asymptomatic other than noting the urge to cough on deep inspiration. He had no chest pain, denied any previous hemoptysis, and had no fever, rigors, cough, or sputum production. He denied any history of lung disease including tuberculosis. He had been exposed to asbestos while doing brake work as a mechanic, but otherwise had no occupational or recreational exposures. He had a 5 pack-year history of smoking. His past medical history was notable for surgical repair of an aortic coarctation at age 16. His medical history was otherwise unremarkable and he took no medication.

On physical examination, the patient was afebrile with a heart rate of 90 bpm, respiratory rate of 18/min, and blood pressure of 133/78 mm Hg. He appeared comfortable at rest. Crusted blood was noted about the right nares; the head and neck were otherwise normal. Rhonchi were heard at the right lung base while the left lung field was clear. The remainder of the physical examination was unremarkable.

Initial laboratory investigations at our institution revealed that the patient's hemoglobin had dropped to 12.4 g/dl. The white blood cell count was 9,800/[mm.sup.3], and platelets, 274,000/[mm.sup.3]. Prothrombin and partial thromboplastin times were normal, as were values for BUN, creatinine, and urinalysis. Plain chest radiograph is shown in Figure 1.

Because the aortic knob was ill-defined on chest x-ray film, a thoracic computed tomography scan was obtained. This showed a 2-cm soft tissue density adjacent to the proximal descending thoracic aorta (Fig 2), as well as patchy infiltrates in several lung segments bilaterally.

Diagnosis: Aortobronchial fistula at the site of previous aortic repair

Aortography demonstrated a pseudoaneurysm of the proximal descending thoracic aorta projecting in a posterolateral direction (Fig 3). Fiberoptic bronchoscopy revealed no endobronchial lesions and no active bleeding.

On the basis of the pseudoaneurysm with adjacent airspace disease, fistulous connection between the pseudoaneurysm and the bronchi was suspected. Thus, the patient underwent thoracotomy which confirmed the presence of a pseudoaneurysm and fistula arising from the junction between a pre-existing Dacron patch and the aortic wall. The pseudoaneurysm was removed and the patient had an unremarkable postoperative course.

Mycotic aneurysms or traumatic pseudoaneurysms were common causes of fistula formation in earlier reports of aortobronchial fistulae. In more recent literature, fistulae arising from an area of previous thoracic aorta vascular procedure are reported increasingly. A recent review described 63 reported aortobronchial fistulae.[1] Virtually all patients with aortobronchial fistula experienced at least one episode of hemoptysis. Plain roentgenographic findings were most often nonspecific consisting of pulmonary infiltrates. An aneurysm was definitively diagnosed from the plain film in only 16 percent of the cases. Although computed tomography demonstrated the presence of thoracic aneurysm in over 90 percent of cases, the actual fistula was seen in only half of these cases.[1] Aortography revealed the aortic abnormality in over 90 percent of cases, but in only 17 percent of cases did angiography reveal the actual fistulous tract.[1] Prognosis following surgical repair of aortobronchial fistula was good with 76 percent undergoing successful repair. Without surgical intervention, all reported cases of aortobronchial fistula were fatal.[1]

Aortobronchial fistula following repair of an aortic coarctation has been described five times previously. The time interval from initial aortic repair to presentation with hemoptysis ranged from 1 month[2] to 5 years.[3] All patients presented with hemoptysis. Two patients also presented with fever and subsequently had documented staphylococcal sepsis. Chest radiograph at the time of presentation was normal in one case,[4] while the remaining cases revealed densities adjacent to the aortic graft area[2,5] or infiltrates suggestive of aspirated blood.[3] Only one case included CT scanning which demonstrated an irregular mass of perigraft soft tissue around the lower anastomotic site.[3] Aortography was performed on three of the five patients, confirming the presence of pseudoaneurysm at the graft site in two cases,[3,6] but was normal in the other.[2] In no instance was the actual fistulous tract visualized on aortography or CT scan. In all five patients, the presence of aortobronchial fistula was confirmed at thoracotomy.

As in the five previously described cases of aortobronchial fistula secondary to surgical repair of aortic coarctation, this patient presented with hemoptysis. While a pseudoaneurysm was demonstrated on CT scanning and aortography, no definite fistula was identified until surgery. This case differs from those previously described in the 17-year interval between surgery and the presentation with hemoptysis. Hence, the clinical presentation of aortobronchial fistula following repair of aortic coarctation may be delayed for a long period. CT scanning or aortography may not clearly document a fistulous tract, although other radiologic abnormalities compatible with pseudoaneurysm may be seen. It is necessary to consider aortobronchial fistula as the cause of hemoptysis in any patient with a compatible clinical history, as a favorable patient outcome may be achieved with its recognition and surgical intervention.

REFERENCES

[1] MacIntosh SL, Parrott JCW, Unruh HW. Fistulas between the aorta and tracheobronchial tree. Ann Thorac Surg 1991; 51:515-19

[2] Salomon J, Levy MJ. Aorticopulmonary fistula following repair of coarctation of the aorta. Isr J Med Sci 1974; 10:666-69

[3] Garniek A, Morag B, Schmahmann S, Rubinstein ZJ. Aortobronchial fistula as a complication of surgery for correction of congenital aortic anomalies. Radiology 1990; 175:347-48

[4] Davey MG. Aorto-pulmonary fistula due to failure of an Ivalon graft for coarctation of the aorta. Thorax 1962; 17: 363-65

[5] Grillo IA, Kimball KG, Hardy KL, May IA. Recurrent aortopulmonary fistula. Ann Thorac Surg 1968; 5:459-63

[6] Boerema I. Repair of a traumatic false aneurysm of the aorta perforating into the bronchus. J Cardiovasc Surg 1971; 12:93-4

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