Airway obstruction due to bilateral giant pulmonary artery aneurysms.

ABSTRACT: Large pulmonary artery aneurysms are rare, but they are associated with significant morbidity and mortality. Significant airway obstruction due to extrinsic compression solely by a pulmonary artery aneurym is an extremely rare occurrence. We present a case of large bilateral pulmonary artery aneurysms causing extrinsic airway compression with collapse of the left primary bronchus in a 51-year-old woman. This is the first report in an adult in which airway compression due solely to the pulmonary artery aneurysm resulted in airway collapse. Furthermore, we describe the use of interventional bronchoscopy with stent placement as a minimally invasive alternative to surgery for treatment of these patients.

PULMONARY ARTERY ANEURYSMS (PAAs) are rare. (1) Depending on their size and location, they may lead to significant complications including airway compromise in rare cases. We believe we are presenting the first reported case of an adult with bilateral PAAs in which both primary bronchi were markedly narrowed resulting in airway collapse. Only one other case of airway occlusion in an adult, which was due to a vascular aneurysm, has been reported, but in that case both the aorta and pulmonary artery were involved. (2)

CASE REPORT

A 51-year-old woman with a history of coronary artery disease, systemic hypertension, pulmonary embolism, and asthma presented with chest pain and dyspnea. She was an obese African American woman in moderate respiratory distress, with blood pressure of 138/88 mm Hg, heart rate 128/min and regular, respiratory rate 36/min, and temperature 36.7[degrees]C (98.2[degrees]F). On cardiac examination, a precordial 2/6 holosystolic murmur was heard, and the second heart sound was increased. Examination of the lungs revealed diffuse bilateral expiratory wheezing, greater on the left. The remainder of the examination was noncontributory. Sublingual nitroglycerin, intravenous furosemide, and intravenous methylprednisolone were given for presumptive congestive heart failure and/or asthma exacerbation before transfer to our institution. Myocardial infarction was ruled out. Laboratory studies were noncontributory. The patient required oxygen via nasal cannula at 6 L/min to achieve oxygen saturations >92%. An electrocardiog ram showed normal sinus rhythm with a first-degree atrioventricular block and right axis deviation. A chest roentgenogram showed opacification of the left lung and a large mass projecting over the right hilum (Fig 1). Transthoracic echocardiography revealed four-chamber cardiac dilatation, a dilated aortic root and pulmonary artery, and severe mitral regurgitation. The estimated pulmonary artery systolic pressure was 50 mm Hg. The left ventricular ejection fraction was 50%. Findings on venous duplex scan of the lower extremities were normal. Computed tomography of the chest with intravenous contrast medium showed cardiomegaly with a 100 mm dilatation of the right pulmonary artery and 85 mm dilatation of the left pulmonary artery (Fig 2). A ventilation-perfusion lung scan was read as showing low probability for pulmonary embolus. Flexible bronchoscopy revealed significant extrinsic compression of both primary bronchi, the left with an estimated 80% to 90% stenosis (Fig 3). The patient was intubated with a 12 m m rigid bronchoscope (Dumon, Bryan Corp, Woburn, Mass) and a 14 x 40 mm coated wire mesh wallstent (Microvasive, Boston Scientific, Natick, Mass) was placed in the left primary bronchus and dilated with a balloon, reestablishing airway patency (Fig 3). The distal airways were normal.

The patient was transferred to the MICU after the procedure. She had an uncomplicated myocardial infarction during the perioperative period. Her oxygen requirements decreased over time, she had an uneventful hospital recovery, and she was discharged to home.

DISCUSSION

Large PAAs are rarely reported. In the pre-antibiotic era, the incidence of PAA was estimated to be only 8 per 100,000. (3) Nevertheless, PAAs are associated with a high morbidity and mortality, usually due to the common presence of underlying pulmonary hypertension and the risk of rupture. (1) Defining the underlying cause of these lesions is difficult, but certain associations are frequently seen. These aneurysms are most commonly encountered in the presence of pulmonary hypertension and congenital or acquired cardiovascular abnormalities, with approximately half being associated with congenital heart disease. (4,5) Infection is also a common cause of acquired PAA, with syphilis and tuberculosis having been major causes in the past. (4)

In 1988, Bartter et al (1) presented a classification of PAA based on the presence or absence of arteriovenous communication. Causes of PAA without arteriovenous communication include infections (eg, tuberculosis, syphilis, bacterial, and fungal), congenital or acquired structural cardiac or vascular abnormalities, vasculitis (Behcet's disease and Hughes-Stovin syndrome), pulmonary artery hypertension, trauma and postoperative changes. Congenital PAAs with arteriovenous communication occur in isolation approximately 60% of the time; the rest occur in association with hereditary hemorrhagic telangectasia. (1,6)

The clinical manifestations of PAA are diverse and nonspecific. Commonly reported symptoms associated with PAA include exertional dyspnea, hemoptysis, cough, and chest pain or tightness. As in the case of our patient, these symptoms can easily be attributed to other disorders. Signs of right ventricular failure (edema, ascites) may be evident, and a harsh holosystolic murmur, a diastolic murmur, tachycardia, tachypnea, thrills, polycythemia, anemia, and leukocytosis can all be detected on presentation but again are nonspecific. If an arteriovenous communication exists, the development of a right-to-left shunt may cause cyanosis, clubbing, and paradoxical emboli to the brain.

Findings on the chest roentgenogram are usually abnormal, but the abnormality can often be mistaken for another more common lesion, such as a neoplasm. Failure to include PAA in the differential diagnosis of pulmonary masses and nodules can lead to a potentially dangerous needle biopsy of a suspected mass. (7) Computed tomography is often the best diagnostic imaging tool. Magnetic resonance imaging has also been used and may avoid the need for contrast medium. Chest fluoroscopy, though not currently used, might reveal a pulsation known as "Pezzi's sign" or the "hilar dance." (8) Echocardiography may also be used to detect PAA, but its main role is the detection and quantification of pulmonary hypertension and other associated cardiac or aortic abnormalities. Finally, angiography remains the standard for diagnosis.

Airway compression due solely to an enlarged PAA has not been previously reported in adults. The ability of PAA to cause airway compression depends on its location in relation to the airways and its size. Our case appears to be the first report of an adult with bilateral PAA that led to airway collapse without an associated congenital or anatomic cardiac or aortic anomaly.

The treatment of patients with PAA is complicated, and as the disease progresses the therapeutic alternatives become limited. Initially, therapy should be directed at treating all underlying diseases (eg, infections, vasculitis). Once the underlying condition has been appropriately addressed, attempts at correcting the PAA itself may be considered. (1) If the aneurysm involves the main pulmonary artery trunk, surgery with aneurysmectomy is the only possible intervention. With more peripheral lesions, options include both vascular ligations with resection of distal vascular dilations and nonsurgical embolotherapy. In the case of embolotherapy, the preferred occlusive materials used are wire coils and detachable balloons. (1) With advanced disease, large aneurysms develop, usually reflecting severe pulmonary hypertension and conveying a high mortality. (1) Furthermore, the high morbidity and mortality among these patients and the commonly associated cardiovascular disease make these patients poor surgical candidates, as was the case in our patient." (1,2) Surgery was also considered prohibitive in a case similar to ours, in which a patient had airway compression between an aortic aneurysm and an enlarged pulmonary artery. (2)

Considering our patient's high surgical risk, we elected a conservative approach with interventional bronchoscopic placement of a wire mesh stent. The occurrence of a myocardial infarction after the procedure corroborated the high surgical risk. In the end, the patient reported substantial relief of symptoms after the procedure, which was anticipated from the successful reestablishment of airway patency.

To diagnose PAA, the clinician must have a high degr111ee of suspicion. Failure to recognize this lesion early allows it to continue growing, perhaps to a stage that would limit therapeutic alternatives and increase morbidity and mortality. Finally, we find interventional bronchoscopy a suitable therapeutic alternative for these high-risk patients who have airway compromise.

References

(1.) Bartter T, Irwin RS. Nash G: Aneurysm of the pulmonary arteries. Chest 1988; 94:1065-1075

(2.) Penner C, Maycher B, Light RB: compression of the left main bronchus between a descending thoracic aortic aneurysm and an enlarged right pulmonary artery. Chest 1994; 106:959-961

(3.) Deterling RA, clagett OT: Aneurysm of the pulmonary artery: review of literature and report of a case. Am Heart] 1947; 34:471-498

(4.) Singh SP, Nath H: Pulmonary hypertension causing pulmonary artery aneurysm. Chest 1999; 116(suppl 2):429S

(5.) Chen YF, Chiu CC, Lee CS: Giant aneurysm of main pulmonary artery. Ann Thorac Surg 1996; 62:272-274

(6.) Hodgson CH, Burchell HB, Good GA, et al: Hereditary hemorrhagic talangiectasia and pulmonary arteriovenous fistula: survey of a large family. N Engl J Med 1959; 261:625-636

(7.) Plokker HW, Wagennar S, Bruscke AVG, et al: Aneurysm of a pulmonary artery branch: an uncommon case of a coin lesion. Chest 1975; 68:258-261

(8.) Boyd LJ, McGavack TH: Aneurysm of the pulmonary artery: a review of the literature and report of two new cases. Am Heart J 1939; 18:562-578

RELATED ARTICLES: KEY POINTS

* Airway obstruction due to many different diseases may be relieved by stenting.

* Relief is often immediate and dramatic.

* Bilateral giant pulmonary artery aneurysms are rare and an extremely rare cause of airway compromise.

* Pulmonary artery aneurysms are commonly encountered in the presence of pulmonary hypertension and cardiovascular abnormalities.

* Surgery is often prohibitive due to comorbidities.

From the Department of Medicine, Section of Pulmonary Diseases, Critical Care and Environmental Medicine, Tulane University Health Sciences center, New Orleans, La.

Reprint requests to Kevin L. Kovitz, MD, 1430 Tulane Ave, SL-9, New Orleans, LA 70112.