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

Abstract

Prenatal diagnosis of pulmonary arteriovenous malformations (PAVM), caused by abnormal communications between pulmonary arteries and pulmonary veins, is rarely described. We report a case of a PAVM between the right pulmonary artery and the left atrium, referred to our prenatal unit at 22 + 1 weeks of gestation, with severe cardiomegaly, dilation of the right pulmonary artery and a right pulmonary vein and retrograde flow in the ductus arteriosus. The fistula was located in the right lung and showed a broad, disturbed flow at color Doppler with high velocity and low pulsatility. The fetus was monitored weekly and cardiac function remained sufficient until 36 + 1 weeks of gestation, when increasing cardiomegaly prompted delivery by cesarean section. The newborn was transferred to the neonatal intensive care unit, intubated and the fistula was surgically removed. The boy could be discharged at the 43rd day of life and showed an uneventful course until the last follow-up at the age of 4 years, with no residual mental or physical handicaps and a normal cardiac function. Despite adverse outcomes described in previously reported cases of large PAVM complicated by severe cardiomegaly at midtrimester scan, our case had a good outcome.

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.…”

Brazilian Fetal Cardiology Guidelines - 2019

“…The most frequent are Galen's vein aneurysm, hemangioma, hepatoblastoma, pulmonary arteriovenous malformation, vascularized tumors such as sacrococcygeal or cervical teratoma, and the twin-twin transfusion syndrome. 54,55 Severe anemia resulting from viral infection or blood type incompatibilities may lead to heart failure. Fetal hemodynamics may also be compromised by extrinsic fetal heart compressions, such as diaphragmatic hernia, pulmonary cystic adenomatoid malformation, and pericardial tumors.…”

Massive Pulmonary Arteriovenous Malformation as a Cause of Fetal Heart Failure

“…These malformations bypass the pulmonary capillaries, resulting in a right-to-left shunt. Rarely, with larger lesions, pulmonary AVM can cause cyanosis in the newborn and high-output heart failure in the early fetal period [ 2 ].…”