Atrial septal defect (ASD) is a heart defect that is present at birth (congenital). While the baby is in the womb, there is normally an opening between the upper chambers of the heart (atria) to allow blood to flow around the lungs. This opening usually closes around the time when the baby is born.
Atherectomy – A nonsurgical technique for treating diseased arteries with a rotating device that cuts or shaves away material that is blocking or narrowing an artery.
Arcuate arteries – small arteries that lie at the bases of the renal medullary pyramids. They normally appear as thread-like echogenic structures that should not be confused for calculi.