After a blocked artery is treated with angioplasty to restore blood flow, the artery may become blocked again. This is called restenosis. One way to prevent restenosis is to place a stent inside the artery at the spot where the blockage was cleared by angioplasty. A stent is a tiny, metal mesh tube that is placed with a catheter and permanently embedded within the artery wall to prop open and prevent it from collapsing.
Associations between Agent Orange and other dioxin-contaminated herbicides and structural birth defects like spina bifida, oral clefts, heart defects and hypospadias may be just the âtip of the icebergâ.
Many other birth defects appear to be caused by multiple genes and environmental factors, adding to the complexity of understanding their causes. For example, March of Dimes grantees have discovered genes that contribute to heart defects and to cleft lip/palate, both of which are among the most common birth defects. However, in most cases, the causes of these defects remain unknown.