Pulmonary Artery Stenosis

Pulmonary artery stenosis (PAS) is largely divided into two distinct categories depending on the location of the stenosis: type 1 and type 2. Type 1 PAS involves one or multiple sites of arterial stenosis found in the main pulmonary artery or its major branches, whereas type 2 PAS results in one or more narrowings in the peripheral branches of the pulmonary arteries [1].

Patients may be pediatric but the condition might as well be diagnosed during adulthood. Some individuals with arterial stenoses that amount to less than 50% of the vascular diameter may experience no symptomatology. Patients with more profound stenosis usually exhibit dyspnea and fatigue, poor appetite, tachypnea, and low exercise tolerance, while cyanosis, tachycardia, peripheral edema, and ascites are also possible. Dyspnea and fatigue constitute the symptoms typically involved in the vast majority of PAS cases and are typically elicited following exercise; most individuals are in their second decade of life when symptoms are initially reported [2]. Hepatomegaly may also be found and together with peripheral edemas greatly suggest the existence of right ventricular failure on the grounds of PAS.

In general, most patients affected by type 1 pulmonary artery stenosis are asymptomatic. The most common finding that raises suspicion and necessitates further investigations is a continuous, ductus-like murmur heard during cardiac auscultation. On the other hand, type 2 PAS can either be an isolated abnormal finding or manifest as part of another clinical entity such as Alagille syndrome, Williams-Beuren syndrome (WBS), or following pulmonary artery surgical reconstruction [3] [4]. Therefore, patients with peripheral pulmonary artery stenosis may also exhibit symptoms directly associated with one of these disorders, such as dental malformation and mental retardation, that is caused by Williams-Beuren syndrome. Lastly, both Behçet disease and Takayasu arteritis encompass type 2 PAS in their clinical spectrum and patients affected by the aforementioned disorders are also expected to present with corresponding manifestations such as fever, hypertension, and heart failure in the case of Takayasu arteritis, or uveitis, oral aphthous ulcers, and genital ulcers in Behçet disease [5] [6] [7] [8] [9]. Pulmonary hypertension is a common manifestation of type 2 pulmonary artery stenosis.

Pulmonary artery stenosis often presents a challenge concerning its diagnosis, due to the fact that the disorder is often asymptomatic. The patients that do not experience PAS-related symptoms may be diagnosed incidentally during tests conducted for other cardiac abnormalities, whereas those who complain about significant symptomatology are required to undergo various procedures to reach an accurate diagnosis. A complete workup involves the following tests:

• Thoracic radiograph. A chest X-ray may reveal regions of stenosed pulmonary arteries in some patients, by illustrating the dilated section following the stenosis. Pulmonary vessels might appear as diminished, augmented, or normal, depending on the particular characteristics of the vascular abnormality involved.
• Electrocardiogram. It may reveal findings consistent with right ventricular hypertrophy which results from a systolic overload of the structure [10].
• Selective angiocardiography. A procedure that greatly contributes to the diagnosis of PAS.
• Catheter-guided pulmonary arteriography. It is employed to detect areas of stenosis and can also diagnose right ventricular hypertension [11]. It does constitute the gold standard for the detection of peripheral pulmonary artery stenosis [12].
• Pulmonary perfusion imaging. The procedure may reveal localized imbalance in lung perfusion but remains a test with no specificity for PAS [12].

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