Prenatal diagnosis of a pulmonary arteriovenous malformation

Abstract

Pulmonary arteriovenous malformations (PAVMs) CASE REPORTPulmonary arteriovenous malformations (PAVMs) are caused by abnormal communications between pulmonary arteries and pulmonary veins, and are most commonly congenital in nature 1 . They may occur as an isolated anomaly or in association with hereditary hemorrhagic telangiectasia (HHT) (Rendu-Osler-Weber syndrome). The right-to-left shunting induces chronic hypoxemia, cyanosis, clubbing, polycythemia, paradoxical embolism and infections 2 . We describe a case of prenatal diagnosis of PAVM in a 16-week-old fetus.The patient presented for early targeted organ screening at 15 weeks' gestational age. The left side of the fetal heart was enlarged with a shift towards the left thorax; the left atrium was particularly enlarged. The tricuspid valve appeared to be wide with mild regurgitation, and the supravalvular aorta and pulmonary artery were slightly widened.Fetal echocardiographic examination at 16 weeks showed the left heart to be enlarged as compared to the right, particularly the left atrium as compared to the right atrium. At least one muscular ventricular septal defect was present. During two-dimensional gray-scale ultrasound examination, a jet was observed in the posterior portion of the left atrium flowing from one of the right pulmonary veins into the left atrium ( Figure 1a). Longitudinal color Doppler showed antegrade flow in the main pulmonary artery that appeared to be joined to the jet, whose flow direction was posterior-anterior. Applying four-dimensional ultrasound (4DUS) scanning a spatiotemporal image correlation (STIC) volume dataset with color Doppler was acquired. In post-processing multiplanar reconstruction (MPR) we observed in the apical four-chamber view that the jet crossed the mitral valve. With the aid of the navigation dot, we observed in all three orthogonal planes (apical four-chamber view, longitudinal view and coronal C-plane) the area of the junction of the pulmonary artery and what appeared to be a pulmonary vein (Figure 1b and supplementary Videoclip S1). Pulsed wave color Doppler was applied to this area and showed a typical triphasic flow pattern in the shunt, which confirmed it as a pulmonary vein. Flow in the shunt reached maximum velocity of 60 cm/s (Figure 1c). In light of these findings a diagnosis of PAVM was made. Owing to the poor prognosis for this kind of PAVM the parents opted for termination of pregnancy, which was performed by dilation and evacuation (precluding postmortem evaluation). DISCUSSIONPAVMs are direct communications between the smaller pulmonary arteries and veins. These vascular fistulas allow blood to bypass the capillary system, and flow from arteries directly into veins. These lesions are usually congenital and are caused by failure of differentiation of the embryonic vascular plexus. The low-resistance venous system is exposed to systemic pressures leading to abnormal vascular formations 2 . Since the first description at an

Large Fetal Pulmonary Arteriovenous Malformation Detected at Midtrimester Scan with Subsequent High Cardiac Output Syndrome and Favorable Postnatal Outcome

“…Though it is a rare finding, prenatal diagnosis of PAVM has been previously described in a few case reports [2,4,7,8,9,10]. Corresponding to our case, the described 6 fetuses had isolated PAVM and no family history for HHT.…”

“…Especially pregnant women with familial teleangiectasia and arteriovenous fistulas are at high risk of developing hemoptysis and hemothorax during the second half of pregnancy [3]. No general screening test is available, though a known familial genetic defect can reliably be determined in other family members [4], especially two genes (DNA sequencing and deletion duplication analysis of the coding exons of the endoglin gene and the activin A receptor type II-like 1 gene) account for the majority of cases [5]. …”

A case of prenatally diagnosed extrapulmonary arteriovenous malformation associated with a complex heart defect

“…In addition to these findings, it is the first case of a PAVM associated with a complex heart defect diagnosed prenatally. In previous cases of PAVM diagnosed prenatally, three were associated with a congenital heart defect, but a simple disease such as valvular pulmonary stenosis, muscular VSD, and atrial septal defect [169]. In our case, a complex heart defect of DORV with VSD might add the hemodynamic effect to the already exiting shunting through a PAVM.…”

“…In eight previous cases of prenatally diagnosed PAVMs, four infants survived after successful treatment (Table 1) [13456789]. Among four survived infants, one was diagnosed as late as 37 weeks.…”

“…They are quite rare and only a few reports of prenatal diagnosis have been described [123456789]. The cases diagnosed prenatally were reported as an isolated anomaly or in association with simple cardiac defects.…”