Ultrasound thrombolysis.

The possibility of lysing clots by the direct intravascular application of ultrasound was described first in 1974 in an animal experiment. However research on therapeutic ultrasound for thrombolysis gained momentum in the early 1980s and is now divided into several directions: 1) pharmacological thrombolysis supported by externally applied ultrasound; 2) pharmacological thrombolysis accelerated by intravascular ultrasound; 3) lysis of intravascular clots by intravascular ultrasound applied as singular treatment; 4) facilitating angioplasty by intravascular ultrasound which may smoothen the rigid surface of calcified arteries by lysing calcified structures out of sclerotic plaques. In acute myocardial infarction first evidence of efficacy in lysing clots by ultrasound was described in two small series of 15 patients in 1997. Furthermore, ultrasound thrombolysis seems to be efficient also in occluded saphenous vein grafts and in completely obstructed peripheral arteries, where the latest clinical experience gives very promising results.