Intravascular ultrasound in the drug-eluting stent era.

Intravascular ultrasound (IVUS) has become an indispensable part of all drug-eluting stent (DES) studies; findings must be put into context with the IVUS findings in bare metal stents. Unfortunately, there is not yet a complete picture of either the Cypher (Cordis, Miami, Florida) or the Taxus (Boston Scientific, Maple Grove, Minnesota) stent (the two U.S. Food and Drug Administration-approved devices). Intimal hyperplasia volume in DES is reduced to <15% of stent volume, but stent underexpansion continues to be a consistent finding in DES failures (restenosis and thrombosis). The utility of IVUS to assure adequate stent expansion may be more important whenever there are clinical risk factors for DES failure.