Research Information System
22nd World Congress in Fetal Medicine, Praha, Czech Republic, 29 June - 03 July 2025, pp.43-44, (Summary Text)
22nd World Congress in Fetal Medicine
A Rare Case of Type A4 Truncus Arteriosus with Dextrocardia
Emeklioglu CN, Akalin M, Buyukbayrak EE
Marmara University, Pendik Research and Training Hospital, Istanbul, Turkey
Truncus arteriosus is a rare congenital heart defect resulting from incomplete conotruncal septation, characterized by a single arterial trunk supplying systemic, pulmonary, and coronary circulations. It occurs in 3–10 per 100,000 live births, constituting approximately 4% of all critical congenital heart diseases. According to the Van Praagh classification system, truncus arteriosus is categorized into four distinct types, with type 4a representing 2% to 12% of cases. The objective of this report is to present a rare instance of type 4a truncus arteriosus accompanied by dextrocardia, identified during the third trimester of gestation, which had been previously misdiagnosed.
Methods
The patient's clinical records and diagnostic imaging reports, encompassing a detailed analysis of ultrasound images, pertinent findings, and the fetal echocardiogram, were comprehensively reviewed. Furthermore, a thorough search of relevant literature was conducted to contextualize the observed findings.
Results
A 26-year-old primigravid patient, who conceived via in vitro fertilization, presented with a dichorionic diamniotic twin pregnancy. Her medical history included a cerclage procedure performed at the 16th week of gestation due to cervical insufficiency. She presented to our clinic at the 31 st week of gestation, having been previously diagnosed with right atrial isomerism, dextrocardia, and double outlet right ventricle during a second-trimester anomaly scan conducted at another medical facility. Ultrasonography revealed dextrocardia, characterized by both dextroversion and dextroposition. Assessment of the great vessel outlets demonstrated a single arterial trunk originating from both ventricles, with preferential flow from the right ventricle. This common trunk gave rise to the right and left pulmonary arteries posteriorly. A hypoplastic aortic outlet was observed on the right lateral aspect. Further evaluation of the continuity of the hypoplastic aorta revealed an interrupted aortic arch, with the left subclavian artery originating from the ductal arch. Inferior venous return was normal, and no positional anomalies were observed between the aorta and inferior vena cava. Intra- abdominal evaluation revealed a spleen of normal size and position. Assessment of atrial morphologies indicated situs solitus in both atria. Based on these findings, heterotaxy syndromes were deemed unlikely, and the patient was diagnosed with truncus arteriosus type A4, according to the Van Praagh-modified classification system, in conjunction with dextrocardia.
Conclusion
Truncus arteriosus is a rare and diagnostically challenging cardiac anomaly necessitating meticulous evaluation of the ventricular outlets, as well as the diameter and position of the great vessels. Assessment of atrial morphology and abdominal situs is crucial in the evaluation of heterotaxy syndromes. Although second-trimester ultrasound screening has demonstrated accuracy in diagnosing the majority of fetal cardiac anomalies, third- trimester ultrasound remains equally important. Reliance on prior diagnoses should be avoided, and a comprehensive scan should be performed to mitigate the risk of misdiagnosis.