Giant Pulmonary Artery Aneurysm in a Young Male Patient

Abstract

Pulmonary artery aneurysm (PAA) is a rare disease. Its causes can be varied and, in some patients, unidentified. Diagnosis is problematic because most patients are completely asymptomatic or present with nonspecific symptoms. Given the rarity of PAA, definitive treatment is still under research. We present the case of a healthy 47-year-old man who had some discomfort during an exercise routine and, because of his family cardiac history, presented to our office. On further evaluation, a giant idiopathic PAA was detected and successfully treated.

Idiopathic pulmonary artery aneurysm (PAA) is a rare disorder that has been reported in fewer than 100 cases.^1,2 It is usually asymptomatic.² Nonetheless, it represents a potentially life-threatening condition that needs prompt diagnosis and treatment.1 We present the case of a 47-year-old male patient with a giant PAA who fully recovered after surgical treatment.

The patient is a 47-year-old man without any past medical history. While doing his exercise routine, he experienced chest pain; the pain was transitory and disappeared after a few minutes. Because his family members had histories of heart disease, he decided to consult his cardiologist. On clinical examination, a healthy patient was encountered; he denied episodes of dyspnea or palpitations. An electrocardiogram revealed normal sinus rhythm, but the chest roentgenogram showed a widened mediastinum. Therefore, transthoracic echocardiography was obtained, revealing a 51-mm main PAA. There was mild dilation of the right ventricle and atrium without hypertension. The tricuspid and pulmonary valves appeared normal, without regurgitation or stenosis. With these findings, computed tomography angiography was performed to evaluate this aneurysm. The imaging confirmed the diagnosis of a large main PAA, without signs of rupture or thrombus, measuring 75 mm (axial), 55.3 mm (sagittal), and 58 mm (coronal). The right and left pulmonary arteries were also dilated (40 mm and 50 mm) (Figure 1).

Figure 1.

(A) Angiotomography of the pulmonary artery aneurysm. (B) Angiotomography of the division of the pulmonary artery. (C) Tomographic reconstruction of the aneurysms. (D) Division of the pulmonary arteries.

After explaining his condition to the patient, a cardiothoracic assessment was needed, and surgical treatment was chosen. After performing a median sternotomy, we identified significant dilation of the main, right, and left pulmonary arteries and mild dilation of the right ventricle and atrium. To initiate the repair, we achieved cardiopulmonary bypass and deep hypothermic circulatory arrest with cold blood cardioplegia. We then dissected the main, right, and left pulmonary arteries. We discovered that the pulmonary arteries had thin walls without signs of dissection or thrombus, and the pulmonary valve annulus was not compromised.

Therefore, a longitudinal incision of the anterior wall of the pulmonary trunk was achieved, allowing us to remove the aneurysm. Because the aneurysm was near the pulmonary valve, we made sure that the graft would not impede the movement of the valve and cause functional stenosis or valve incompetence. The arteries were substituted using an artificial blood vessel (polyethylene terephthalate [Dacron]). It measured 22 mm in diameter and was positioned 1 cm away from the pulmonary valve. It was anastomosed with a 4-0 nonabsorbable polypropylene suture in a 1-layer fashion and reinforced with bovine pericardium. The right and left pulmonary remnants were also anastomosed to this artificial blood vessel without complications. We made sure that the right pulmonary graft path under the aorta was not under any tension that would cause stenosis or kinking. Subsequently, after meticulous hemostasis and avoiding damage to nearby structures that would cause bleeding of bronchial fistulas, the heart was deaired, and the patient was rewarmed and weaned from cardiopulmonary bypass without complications (Figures 2A, 2B).

Figure 2.

(A) Pulmonary artery reconstruction. (B) Postoperative chest roentgenogram without pleural effusions. (C) Pathologic features. The wall of the aneurysm is seen with all its layers (original magnification 20X). (R, right.)

Pathologic examination revealed that the vessel wall was fragile, with dilatation of all 3 layers. Idiopathic PAA was the final diagnosis (Figure 2C).

His postoperative course was uneventful. He was admitted to the intensive care unit, had no complications during his stay, and was discharged to a general ward room 2 days postoperatively. The thoracic drain was removed because of low and serous production, and after a complete diet was tolerated, he was discharged without complications (Figure 3). On follow-up visits, the patient is doing well, without signs of complications.

Figure 3.

Drawing of the surgical procedure.

Comment

PAA is a rare condition (1 in 14,000 individuals) first described by Bristowe and colleagues in 1860, characterized by extreme dilatation involving all 3 layers of the main pulmonary artery or its branches.^1,2 Although there is no standard definition of PAA, most investigators describe it as a dilatation greater than 1.5 times the standard upper limit (43 mm in men and 40 mm in women).¹ Several explanations have been proposed to describe the origin of PAA, including congenital, acquired, iatrogenic, and idiopathic.^1,3 Idiopathic PAA is extremely rare, with few cases described in the English literature.^2,4 PAA arises without a specific cause. ⁵ However, it is characterized by dilatation of the pulmonary trunk, the absence of cardiac shunts, the lack of cardiac or pulmonary disease, and the absence of arterial disease,³ as we discovered in our patient.

Limited data exist on the pathophysiologic pathways in PAA; the most accepted view is that the flow caused by left-to-right shunts or pulmonary hypertension results in increased stress on the vessel walls and promotes aneurysm formation.^1,5Clinical manifestations of PAA are nonspecific, and many patients can remain asymptomatic even with a large PAA; other patients present with dyspnea, chest pain, cough, and bronchiectasis.^1,6 As the aneurysm grows, patients have a high incidence of pulmonary emboli, hemoptysis, dissection, and rupture.^1,5,6 Rupture and dissection are the most dreaded complications because they can be lethal.^7,8 In our case, our patient presented with mild chest pain, and after evaluation, we detected a large aneurysm.

The diagnosis is difficult when it is based on clinical features.^1,7 Nonetheless, a systolic heart sound can develop in these patients.^1,2,8 An electrocardiogram may show signs of right ventricular or atrial hypertrophy, and a standard chest roentgenogram may show hilar enlargement.^1,2,6,8

Imaging is critical for PAA.^1,4 Echocardiography can assess heart function, yet angiography and contrast-enhanced computed tomography are needed to evaluate the aneurysm and its characteristics.¹ In our patient, the chest roentgenogram revealed a widened mediastinum, which forced us to investigate further and allowed us to identify the PAA. Treatment depend on the aneurysm’s size and symptoms.^1,5 Conservative therapy for asymptomatic patients without pulmonary hypertension can be reasonable but needs close surveillance along with medication.^1,3,7 Surgery is required if the PAA is ≥5.5 cm or the diameter increases by ≥0.5 cm in 6 months.¹ Urgent surgery is needed if there is compromise of neighboring structures, thrombus, rupture, or dissection.⁸ Dacron prosthesis, homograft interposition, reconstruction with a pericardial patch, aneurysmorrhaphy, arterioplasty, and plication are among the available surgical options, yet the only treatment that offers full recovery is aneurysmectomy and repair of the right ventricular outflow if the pulmonary valve is affected.^1,2,8 In our patient, given the size of the PAA and his symptoms, the compromised arteries were replaced to remove the aneurysm without complications.

Idiopathic PAA is rare and difficult to diagnose because of its nonspecific symptoms. Imaging is essential to evaluate and delineate preoperative and surveillance procedures. Close surveillance is necessary to avoid complications and plan for safe surgical treatment.

In conclusion, PAA is a rare disease that does not manifest with distinguishable symptoms; thus, diagnosis and treatment are challenging. In these rare disorders, joint efforts of the medical, surgical, and diagnostic teams are essential to provide these patients the opportunity to achieve complete recovery. Further research is needed regarding the diagnostic criteria, follow-up imaging, and treatment.