Introduction

Congenital cardiovascular anomalies are the most common birth defects in fetuses. Among these, vascular rings form a rare entity, with an estimated incidence of 1 to 1.3 per 10,000 live births, accounting for less than 1% of all congenital cardiovascular malformations [1].

This condition is characterised by abnormal formation of the main vessels that encircle the trachea and oesophagus, frequently causing mechanical compression of these structures, which may then lead to respiratory and gastrointestinal complications [2, 3].

The embryonic arterial system develops from six pairs of pharyngeal arches that connect the truncus arteriosus to the dorsal aortae. The arches then undergo a selective process of regression and remodeling. Due to the complexity of this process, even minor changes may lead to vascular anomalies. A normal, left-sided aortic arch develops mainly from the left 4^th embryonic arch and the left dorsal aorta. However, if this process is disrupted and the right 4^th arch also persists, a double aortic arch is formed, which is the most common variant of the vascular ring [4]. It can also be formed by a right aortic arch that is closed by a ligamentum arteriosum, often combined with an aberrant subclavian artery.

The severity of symptoms depends directly on the specific anatomical type and the extent of this developmental disorder. In severe cases, neonates and infants manifest symptoms of upper respiratory or gastrointestinal obstruction, including stridor, recurrent respiratory tract infections, wheezing, dyspnoea, dysphagia, and choking during feeding. Nevertheless, some patients may also remain asymptomatic [5]. Advances in prenatal diagnostics, particularly in fetal echocardiography, are increasingly allowing the detection of upper mediastinal anomalies at an early stage, which are often difficult to diagnose postnatally. This was achieved, among other factors, through the introduction of the 3VT view into routine prenatal screening – an advancement that has improved the detection of selected cardiac and great vessel anomalies, enabling precise planning of perinatal care and treatment [6, 7].

Case report

A 30-year-old primigravida with a high-risk pregnancy (gestational diabetes, pregnancy-induced hypertension, Hashimoto disease, and obesity) underwent routine prenatal examinations at 12 and 18 weeks of gestation, which were reported as normal. At 20 weeks, an abnormal origin of the great vessels was detected the first time by an obstetrician. At 24 weeks, a right-sided aortic arch with mild aortic dextroposition was suspected. Following these findings, the patient was referred to the Department of Prenatal Cardiology Polish Mother’s in at 28 weeks of gestation for further evaluation. Eventually, at 28 + 6 weeks in a male fetus, a vascular ring was confirmed and described based on targeted fetal echocardiography in three-vessel and trachea view (3VT view), consisting of a right aortic arch, a left-sided ductus arteriosus, and additional encircling vessel. No extracardiac anomalies were identified. During follow-up fetal echocardiography at 35 weeks, accelerated flow through the ductus arteriosus (V max – 180 cm/s) and interventricular septal hypertrophy (SEP ) with right ventricular overload (Tei RV: 0,76) were noted (Figures 1 and 2). A three-vessel umbilical cord was also noted around the fetal neck. During fetal echo monitoring the four-chamber view of the heart was “normal”, but its size was at the upper limit from 28 weeks () up to 35 weeks () (Figure 3).

Based on prenatal findings, the schematic drawing was prepared as part of the written medical record (Figure 4).

The patient provided written informed consent for the publication of their clinical details and images.

Postnatal course

The neonate was delivered at 39.9 weeks via caesarean section due to maternal orthopaedic indications, with a birth weight of 3130 g and an Apgar score of 8/8.

Computed tomography (CT) angiography of the chest revealed an ascending aorta that divided before the arch into two branches: a dominant right arch and a hypoplastic left arch. These vessels formed a complete vascular ring encircling the trachea and oesophagus, merging into a singular descending aorta at the level of the tracheal carina. Slight tracheal compression was noted, with a maximum lumen diameter of 5.5 × (Figures 5 and 6).

On the 3^rd day of life, a chest X-ray of the newborn was performed, which revealed no abnormalities (Figure 7).

The general condition of the neonate assessed in the Neonatology Department was good, with no respiratory or feeding dysfunctions. The patient was discharged on the 15^th day of life with a recommendation for further follow-up.

At the age of 7 months, the male infant was readmitted due to intermittent choking during feeding. Due to the clear prenatal diagnosis, the patient was scheduled for elective surgical correction of the vascular ring. A chest X-ray was performed, which demonstrated an increased cardiothoracic ratio (CTR ≈ 0.67), suggestive of cardiomegaly. The cardiac position was normal with no significant pulmonary abnormalities (Figure 8).

The infant underwent a surgical division of the ring and transection of the arterial ligament and was then transferred to the Paediatric Cardiac Intensive Care Unit for postoperative monitoring with continued mechanical ventilation. The child was successfully extubated during the afternoon hours the same day without any airway complications, allowing the patient to be transferred to the Cardiac Surgery Department the next day.

Follow-up echocardiography demonstrated good cardiac contractility with no evidence of pericardial effusion. The child was discharged from hospital in good general condition.

Discussion

Vascular rings remain a diagnostic challenge in prenatal cardiology despite advances in fetal cardiology. One of the main reasons for a missed diagnosis is their rarity, which may lead to lower suspicion and reduced attention during standard examinations. Additionally, most pregnancies undergo only basic ultrasound assessment, while detailed fetal echocardiography is usually used in high-risk cases [8]. The standard screening is based on the four-chamber view, which often appears normal in these anomalies and may provide false reassurance. As demonstrated in our case, the four-chamber view remained unremarkable throughout gestation, even though the fetus had a clinically significant vascular abnormality.

The clinical presentation of vascular rings is variable, ranging from completely asymptomatic cases to severe respiratory and feeding difficulties. Symptoms may not be present in the neonatal period or occur as nonspecific symptoms, which can delay correct diagnosis after birth. Undetected cases may lead to prolonged and unnecessary treatment and potentially life-threatening complications [9]. Early prenatal diagnosis is crucial because it allows for appropriate postnatal monitoring and timely intervention, and it is associated with improved clinical outcomes and better prognosis [10].

The most important ultrasound projection for detecting vascular rings is the three-vessel and trachea view (3VT). This view allows for visualisation of the spatial relationship between the aortic arch, ductus arteriosus, and trachea, which is essential for identifying these anomalies [11, 12]. In the presented case, it was the repeated and detailed assessment of the 3VT view, combined with the colour Doppler imaging, that enabled confirmation of the diagnosis.

The diagnostic process in this case highlights the importance of targeted evaluation after finding the initial subtle anomalies.

Compared to previously published cases, our observations are consistent with the literature in several aspects; the presence of right aortic arch combined with a left-sided ductus arteriosus represents a common anatomical variant leading to complete vascular ring. Additionally, the absence of symptoms in the neonatal period followed by the development of feeding difficulties later in infancy corresponds with known clinical patterns, where severity of the symptoms depends on the degree of compression of trachea and oesophagus. Finally, the favourable surgical outcome observed in this patient aligns with reports indicating good prognosis when timely diagnosis and intervention are achieved [10].

Conclusions

The occurrence of feeding difficulties and choking episodes during the second half of the first year of life, together with appropriate prenatal assessment, allowed for timely referral to a cardiac centre and early correction. This case highlights the diagnostic challenge of vascular rings, as the standard four-chamber view seemed unremarkable, and only detailed assessment using the 3VT view enabled the confirmation of the malformation. This demonstrates the importance of including the 3VT view in routine prenatal screening for detecting these subtle anomalies.

Disclosures

Ethical considerations: not applicable.

This research received no external funding.

The authors declare no conflict of interest.