Catheter systems for having both a thermodilution action and a body obstruction destruction action, and methods for determining blood flow rates and for performing body obstruction destruction

A method of performing destruction of a body obstruction in a body vessel of a live being, the method comprising:

• advancing a catheter to a desired location comprising said obstruction within the body vessel, the catheter including a catheter shaft comprising a proximal end and a distal end, comprising an outer tubular member and at least one inner tubular member disposed within the outer tubular member;
• a first fluid lumen defined between the inner tubular member and the outer tubular member and at least one second lumen defined by the inner tubular member;
• one or more fluid exit openings located at a distal end region of the catheter configured to permit fluid to exit the catheter from the first fluid lumen;
• providing a delivery of a fluid through the first fluid lumen to a distal end region of the catheter and at a pressure range predetermined to exit said fluid at a pressure and for a period of time causing destruction of said obstruction.