Giant pulmonary artery aneurysm in a patient with rheumatic mitral stenosis.

Pulmonary artery (PA) aneurysm is a rare condition, frequently associated with pulmonary hypertension. However, the evolution and treatment of this pathology is still not clear. We report a case of a 45-year-old female patient with giant PA aneurysm associated with rheumatic mitral stenosis and severe pulmonary arterial hypertension. The patient had undergone balloon mitral valvotomy around 7 years back; aneurysm was first identified 3 years back during routine follow-up. The PA aneurysm size, however, had remained almost unchanged with associated severe pulmonary regurgitation. Surgical correction was advised but denied by the patient. To our knowledge, this is the first case report of such a large PA aneurysm in association with rheumatic heart disease. Although medical therapy for pulmonary hypertension was started, surgical correction of the aneurysm was advised in order to prevent the future complications.

INTRODUCTION

Pulmonary artery (PA) aneurysm refers to dilatation of the PA. Although some authors have proposed a cut-off of 4 cm in diameter in the past,[1] a clear definition of PA aneurysm is not available as for aortic aneurysms.[2]

It used to be an autopsy finding due to its asymptomatic course in the majority of the cases.[3] It is a rare anomaly found in 1 of every 14,000 autopsies and most of these anomalies are present in the main PA. Several etiologies have been described in the pathogenesis of PA aneurysm, namely, pulmonary hypertension (PH), congenital heart disease, Behηet disease, infections such as the formerly prevalent syphilis, arteriovenous fistulas, connective tissue diseases, atherosclerosis, and trauma.[34]

Since the introduction of antibiotics, non-infective causes of PA aneurysms have become more common.[4] With the technological advances in medicine, PA aneurysms have been diagnosed in living patients by 2D-echocardiography, computed tomography, and magnetic resonance imaging.[5] The pathophysiology of the PA aneurysm is related to vessel wall stress that leads to progressive dilatation of the vessel or even rupture. Thus, once formed, an aneurysm tends to gradually enlarge.[6] Aneurysm dissection is a potentially fatal complication in about one third of the patients,[6] but other serious complications of large PA aneurysms can also occur, namely, airway compression and thrombus formation.[3] Nonetheless, due to the low prevalence of PA aneurysms the optimal management is still unclear.

CASE REPORT

A 45-year-old woman, known case of rheumatic mitral stenosis had undergone balloon mitral valvotomy in 2007. She presented with a 6-month history of dyspnea on exertion (New York Heart Association Class II, NYHA II) without dizziness, syncope, or chest pain. Her prior medical evaluation revealed in addition, pulmonary arterial hypertension (PAH) and a PA aneurysm. On examination the patient was found to have a palpable systolic impulse at the second left intercostal space, a grade 3/6 systolic murmur and a 2/6 diastolic murmur at the lower and upper left sternal border, respectively. Chest radiography showed cardiomegaly and dilation of the main PA and its branches [Figure 1]. A transthoracic echocardiography demonstrated severe mitral stenosis, dilated right and left atria [Video 1], moderate tricuspid regurgitation with PAH (PA systolic pressure, 84 mmHg; Figure 2), an aneurysmally dilated main PA (66 mm) and right (25 mm) and left (24 mm) PA branches [Figure 3a and b, Video 2], and severe pulmonary regurgitation [Figure 4].

Figure 1

Chest X-Ray pulmonary artery view showing cardiomegaly and dilatation of the main pulmonary artery and right descending pulmonary artery

Figure 2

Apical 4C view showing moderate tricuspid regurgitation and severe pulmonary arterial hypertension (pulmonary artery systolic pressure, PASP = 84 mm Hg)

Figure 3

(a) Parasternal short axis view at the level of the pulmonary artery showing aneurysmal dilatation of the main pulmonary artery (measuring 66 mm), (b) The corresponding images in a are shown in 3D-echocardiography showing markedly dilated main pulmonary artery and the bifurcation area

Figure 4

Color doppler imaging in parasternal short axis view at the level of the pulmonary artery showing severe pulmonary regurgitation

For evaluation of pulmonary vasculature, the patient underwent a computed tomographic angiography showing an aneurysm affecting the main PA [Figure 5]. In our patient, the PA aneurysm was associated with PH, this being the most prevalent association, described in 66% of the cases.[3] Dyspnea as a symptom is difficult to ascribe to pulmonary aneurysm as it can occur in both PAH and PA aneurysm. Other symptoms that may be present in patients with PA aneurysms are hemoptysis, cyanosis, clubbing, chest pain, and cough.[4] However, none of these were present in our patient. Intensive medical treatment has been one possible approach for PA aneurysms with clinical improvement of signs and symptoms[4789] and so treatment for PAH was started.

Figure 5

CT Angiography showing aneurysm affecting the main pulmonary artery

Although other authors have reported PA aneurysms, as per our knowledge this is the largest described in a patient with rheumatic heart disease. Moreover, it would be challenging to ascertain whether pulmonary regurgitation was the cause of pulmonary dilation or on the contrary, if it was a consequence of the progressive dilation of the pulmonary trunk; severe pulmonary regurgitation with volume overload might play a role on the persistence of the pulmonary aneurysm.

CONCLUSION

The case report presented illustrates a case of PA aneurysm diagnosed in a living patient with PAH. Although this association is rather frequent, this is probably the first case described associated with rheumatic heart disease. Despite medical therapy for PH being commenced no size reduction was observed on PA aneurysm.

In around 50% of the postmortem cases, pulmonary aneurysms were associated with congenital heart disease, most frequently patent ductus arteriosus. In the remaining reported cases, such aneurysms were associated mainly with secondary acquired lesions, such as syphilis and cystic medial degeneration. The natural history of an untreated idiopathic PA aneurysm has not been well elucidated. It is unclear whether there is a size hinge point similar to aortic aneurysms in which the risk of complication increases.