An apparatus is for use in a vascular space in a body. A catheter has a lumen adapted for communicating fluid between a distal end for insertion in the vascular space and a proximal end. A transducer is adapted for removably connecting to the catheter for contacting the fluid and transmitting energy through the fluid in the lumen for dissolving an obstruction therein. A suction is provided for removing any debris from the obstruction in the lumen of the catheter. The wave guide may be tubular, and may have a length corresponding to the length of the lumen. A catheter or an implantable port including an embedded ultrasonic transducer is also provided.