[Intravascular echography in interventional vascular radiology]

Intravascular US studies were performed with a 20 MHz rotating transducer mounted on a long flexible shaft in 14 patients undergoing interventional vascular procedures--i.e. percutaneous transluminal angioplasty (PTA), atherectomy with a Simpson device, and Palmaz stent placement. Intravascular US was used immediately before the procedure to assess the lesion characteristics and during and after the procedure to verify its results. In PTA, intravascular US clearly shows the fracture of the plaque, its separation from the medial layer, and the total longitudinal extension of the intimal flaps. Palmaz stents are clearly shown and their correct positioning on the arterial wall is therefore precisely evaluated. After atherectomy, intravascular US shows the changes in wall thickness and identifies the areas where more tissue needs to be removed. Intravascular US appears to be a very promising technique for monitoring and directing revascularization procedures by helping select the correct interventional procedure. The initial limitation of use of intravascular ultrasound catheters to straight arterial segments has been resolved by the development of over-the-wire catheters. Further technical development and clinical research are needed.