Symptomatic idiopathic pulmonary artery aneurysm: a case report and a mini-review of the literature.

Am J Cardiovasc Dis 2024;14(4):230-235 www.AJCD.us /ISSN:2160-200X/AJCD0155165 Original Article Symptomatic idiopathic pulmonary artery aneurysm: a case report and a mini-review of the literature Caitlin Merrin, Nyein Chan Swe, George Degheim Department of Cardiology, HCA Healthcare/USF Morsani College of Medicine, HCA Florida Northside Hospital, Saint Petersburg, Florida, USA Received December 28, 2023; Accepted July 10, 2024; Epub August 25, 2024; Published August 30, 2024 Abstract: Pulmonary artery aneurysms (PAAs) are rare, more prevalent in younger population with equal sex incidence. Congenital, idiopathic, autoimmune, infectious, inflammatory, and malignant etiologies have been linked to PAAs. Commonly, patients with PAA are asymptomatic, even those with large PAAs. Presenting symptoms, if any, are non-specific. The management should target the underlying conditions and serial imaging follow-up. Signs and symptoms of disease progression should prompt a change in treatment strategy. Though there is no consensus, those who are symptomatic with a PAA diameter > 5 cm generally should undergo surgical repair. More recently, endovascular interventions are available for certain PAAs. We present a 78-year-old female who was referred to the cardiology clinic for cough and dyspnea. Using computed tomography (CTA) of the chest, she was diagnosed with aneurysm of the main pulmonary artery (PA), without involvement of distal pulmonary arteries or thoracic aorta. She underwent repair of the pulmonary artery using a 34-mm tubular graft with a complete resolution of her symptoms. Keywords: Pulmonary artery aneurysm, aneurysm repair, aneurysmectomy of the pulmonary artery Introduction Pulmonary artery aneurysms (PAAs) are rare abnormalities of the pulmonary vasculature and infrequently diagnosed. Based on 105,571 postmortem examinations at the Mayo Clinic, its incidence is estimated to be 1 in 14,000. PAAs usually occur in the younger population than aortic aneurysms and have equal sex incidence [1]. Aneurysms are defined as a focal dilatation of a blood vessel involving all three layers of the vessel wall while pseudoaneurysms do not involve all three layers of the vessel wall. It is important to distinguish between these diagnoses as pseudoaneurysms have a higher risk for rupture and bleeding [2]. A PAA is described as a focal dilatation of pulmonary artery (PA) beyond maximal normal diameter [3]. There are no standard diameter size parameters to clearly define PAAs [2]. By non-contrast computed tomography (CT), the mean diameter for the main PA in normal healthy adults is 25 mm ± 3 mm with the upper limit of normal in males being 29 mm and the upper limit of normal in females being 27 mm [4]. Generally, PAA can be diagnosed when the main PA diameter is 1.5 times greater than the upper limit of normal (≥ 43 mm in males and ≥ 40 mm in females) [2]. Alternatively, PAA can be diagnosed when the main PA diameter is greater than 45 mm or a branch PA diameter is greater than 30 mm in both males and females [5]. The majority of all PAAs are located in the main pulmonary artery (89%) with the remaining locations within the pulmonary branches (11%) [6]. Additionally, the left PAs were more commonly affected than the right PAs. The etiologies of PAAs includes congenital, idiopathic, autoimmune, infectious, inflammatory, and malignant cause. Historically, congenital causes were most commonly associated with PAAs and attributed to 50% of the etiology [7]. More recent study [2] showed that congenital causes were only 25% of all cases. In general, the presumed mechanism is that increased flow from a left-to-right shunt leads to increased hemodynamic shear stress on the vessel walls https://doi.org/10.62347/DBOS5122 Evaluation and treatment of symptomatic idiopathic pulmonary artery aneurysm allowing aneurysm formation in congenital heart diseases [8]. The most commonly associated congenital heart defects with PAAs are persistent ductus arteriosus, ventricular septal defects, and atrial septal defects [1, 7, 9, 10]. Hypoplastic aortic valve and bicuspid aortic valve have also been identified as significant causes of PAAs [1, 7, 9, 10]. Commonly, patients with PAA are asymptomatic, including those with large PAAs with diameters up to 70 mm [10-12]. Additionally, clinical manifestations are nonspecific which include dyspnea, chest pain, hoarseness, palpitations, and syncope [12-15]. Bronchus compression by a PAA may also cause cyanosis, cough, pneumonia, and fever [10, 12, 16]. Idiopathic PAA may present with hemoptysis and may be a warning for impending rupture [12]. The incidence of pulmonary emboli with PAAs is reportedly high [16]. Rarely, idiopathic PAAs may present with hemothorax or recurrent laryngeal nerve palsy [2]. Other possible associations depending on the underlying etiology include right atrial and ventricular hypertrophy, right heart failure, tricuspid regurgitation due to annular dilatation, and mild pericardial effusion and pleural effusions [13, 14, 16]. PAA dissection is rare but life-threatening and can occur in up to 19% of patients without pulmonary hypertension [12]. About 80% of patients with PAA dissection occur in the main PA trunk and only 15% of these patients are diagnosed alive [10]. PAAs are usually diagnosed incidentally on imaging studies performed for unrelated reasons. PAAs may appear as hilar enlargement, lung nodules, or as a pulmonary mass on a standard CXR prompting additional investigation [8, 10]. The gold standard for diagnosis is pulmonary angiography with the ability to identify the PAA and its involvement with the vascular structures as well as hemodynamic assessment [10]. However, it is invasive and only reveals the interior lumen of the PAA [10, 11, 17]. More common at present, contrast-enhanced CT confirms the diagnosis with the ability to provide additional information such as PAA size, location, and extent [12, 14]. Transthoracic or transesophageal echocardiography is another useful modality to investigate the function of the heart and its valves and possible identification of shunts [10-12, 14]. After a PAA has been diagnosed, the decision for treatment poses another challenge as there 231 are no clear guidelines for the best approach [10]. The management should be tailored to the underlying cause, hemodynamics, and associated comorbidities. A conservative approach comprises medications to target the underlying condition, control of pulmonary hypertension, and imaging follow-up [2]. More invasive surgical options include aneurysmorrhaphy, lobectomy, bilobectomy, aneurysmectomy, and pneumonectomy [2]. Generally, surgical intervention is recommended in symptomatic patients and a PAA with diameter greater than 5 cm [18]. Although, there is no set threshold for intervention, a review by Kreibich et al. [10] suggests surgical repair when the PAA diameter size is greater than 5.5 cm, whereas Seguchi et al. [14] recommends surgical repair w (...truncated)