Prenatal Diagnosis of Idiopathic Infantile Arterial Calcification
A 33-year-old, healthy, G3 P1 woman had had a routine obstetrical ultrasound done at 19 weeks of gestation, which reportedly was normal. Because of decreased fetal activity, a repeat obstetrical ultrasound was performed at 32 weeks. That study showed polyhydramnios and a low biophysical profile, prompting transfer to a high-risk obstetrical center. The fetal echocardiogram, done on the same day, revealed a markedly abnormal heart. The heart looked structurally normal, but the aortic annulus, ascending aorta, transverse arch, descending aorta, main pulmonary artery, and coronary arteries were unusually echo-dense. Both ventricles were dilated, and biventricular function was severely depressed. There was a small pericardial effusion. There was almost no detectable antegrade flow across the pulmonary valve. Flow across the aortic valve was present but very low in velocity. Flow across the foramen ovale and the ductus arteriosus was bidirectional.
Figures 1⇓ and 2⇓ are from that fetal echocardiogram and illustrate dense calcification of the vessel walls. Note that the walls of the extracardiac vessels and coronary arteries have the same acoustic properties as that of the sternum. The diagnosis of probable idiopathic infantile arterial calcification was made. Steroids were administered in preparation for a premature delivery, but the fetus died 36 hours later, just before induction. Postmortem radiographs and fluoroscopy showed subtle evidence of aortic calcification. Figure 3⇓ is from a histological specimen obtained at autopsy. This specimen illustrates the typical findings associated with infantile arterial calcification. There is calcium hydroxyapatite deposition in the internal elastic lamina as well as focal intimal proliferation and thickening of the vessel walls.
Despite extensive investigations of maternal factors, fetal calcium metabolism, and histopathology, the pathogenesis of this disease is still not well understood. The diagnosis is usually made postnatally, although there are rare reports of prenatal diagnosis by ultrasound. Most affected individuals die in the first 6 months, although there have been reports of spontaneous resolution of calcification as well as isolated reports of successful medical therapy.
The editor of Images in Cardiovascular Medicine is Hugh A. McAllister, Jr, MD, Chief, Department of Pathology, St Luke’s Episcopal Hospital and Texas Heart Institute, and Clinical Professor of Pathology, University of Texas Medical School and Baylor College of Medicine.
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