Ultrasonic devices and methods for ablating and removing obstructive matter from anatomical passageways and blood vessels

1. A method of ultrasonically treating an obstruction of a blood vessel, said method comprising the steps of:

a) providing an ultrasound catheter having a proximal end and a distal end, said catheter comprising:

i) an elongate flexible catheter having a proximal end, a distal end and a longitudinal axis extending longitudinally therethrough;

ii) at least one ultrasound transmission member extending longitudinally through said catheter body and coupleable to an ultrasound source, said ultrasound transmission member having a distal end which is substantially coterminous with the distal end of said catheter body;

iii) at least one fluid infusion lumen extending longitudinally through said catheter body and opening through at least one fluid outflow aperture formed at the distal end of said catheter body;

iv) at least one aspiration lumen extending longitudinally through said catheter body and opening through at least one aspiration port formed in the distal most centimeter of said catheter body;

b) inserting said catheter device, distal end first, into the vasculature and advancing said catheter to a point where the distal end of said catheter is adjacent the obstruction to be treated;

c) coupling said ultrasound transmission member to an ultrasound source and utilizing said ultrasound source to pass ultrasound through said ultrasound transmission member to the distal end of said catheter;

d) infusing a liquid infusate through said infusion lumen in contact with said ultrasound transmission member and out of said distal outflow aperture, thereby removing excess heat from said ultrasound transmission member;

e) applying suction to said aspiration lumen to draw matter into said distal aspiration port and through said aspiration lumen of said catheter.

2. The method of claim 1 utilized to treat a cerebral vascular obstruction, wherein step b) of said method further comprises:

inserting said catheter, distal end first, into the vasculature and

advancing said catheter to a point where the distal end of said catheter is positioned in an intracranial or extracranial cerebral blood vessel, adjacent the obstruction to be treated.

3. The method of claim 2 wherein the obstruction to be treated is in a carotid artery and wherein the distal head of said catheter is positioned within said carotid artery adjacent the obstruction to be treated.

4. The method of claim 2 wherein the obstruction to be treated is in a vertebral artery and wherein step b) further comprises positioning the distal end of said catheter within said vertebral artery adjacent the obstruction to be treated.

5. The method of claim 2 wherein the obstruction to be treated is in a basilar artery and wherein step b) further comprises positioning the distal end of said catheter within said basilar artery adjacent the obstruction to be treated.

6. The method of claim 2 wherein the obstruction to be treated is in a anterior cerebral artery and wherein step b) further comprises positioning the distal end of said catheter within said anterior cerebral artery adjacent the obstruction to be treated.

7. The method of claim 2 wherein the obstruction to be treated is in a middle cerebral artery and wherein step b) further comprises positioning the distal end of said catheter within said middle cerebral artery adjacent the obstruction to be treated.

8. The method of claim 2 wherein the obstruction to be treated is in a posterior cerebral artery and wherein step b) further comprises positioning the distal end of said catheter within said posterior cerebral artery adjacent the obstruction to be treated.

9. The method of claim 2 wherein said method further comprises the step of:

maintaining the rate of infusion through said infusion lumen and

maintaining the rate of aspiration through said aspiration lumen such that said rates of infusion and aspiration are substantially equivalent.

10. The method of claim 1 wherein step c) further comprises:

utilizing said ultrasound source to pass ultrasound within the frequency range of 20 kHz to 1 MHz through said ultrasound transmission member to the distal end of said catheter to thereby cause ultrasound induced smooth muscle relaxation and resultant dilation of the anatomical passageway.