Blood-flow-occluding, temperature-sensing catheters and methods of use

Abstract

A catheter assembly for sensing the temperature of an arterial wall or other body lumen includes a blood-flow-occluding feature to increase the accuracy the temperature measurements. In addition to the flow-occluding feature, the catheter includes a distal end with a temperature sensing structure and a proximal end including a manually operated expansion control. The temperature sensing structure including one or more presentation elements in the form of a basket or braided structure having at least one temperature sensor supported thereon, each sensor being operative to generate an electrical signal indicative of temperature. The presentation elements are physically coupled to the manually operated expansion control, such that operation of the control causes the structure to move between a collapsed state, enabling the temperature sensing structure to be positioned in a section of the vessel to be measured, and an expanded state, wherein the sensor is in contact with, or immediately proximate to, the vessel wall. In the preferred embodiment, the feature to occlude blood flow is an inflatable balloon disposed near the expandable basket or braid structure. The temperature sensors are preferably thermistors, and an elastic sleeve covering the expandable basket or braid structure is also preferably provided to further insulate the temperature sensors from the cooling effects of blood flow.

We claim:  
     
         1 . A method of measuring the temperature of a blood vessel wall using a temperature-sensing catheter having proximal and distal ends, the distal end including an expansion device with at least one sensor operative to generate an electrical signal indicative of vessel wall temperature, and the proximal end including a control to operate the expansion device and instrumentation to receive the electrical signal, the method comprising the steps of: 
 inserting the catheter into the vessel such that the temperature-sensing tip is proximate to a point on the vessel wall to be measured;    operating the control to expansion device so that the sensor is in contact with the point on the wall; and    determining the temperature of the vessel wall using the instrumentation by observing the electrical signal several seconds after the sensor makes contact with the vessel wall.    
     
     
         2 . The method of  claim 1 , including the step of observing the electrical signal at five seconds or more after the sensor makes contact with the vessel wall.  
     
     
         3 . The method of  claim 1 , including the step of observing the electrical signal at ten seconds or more after the sensor makes contact with the vessel wall.  
     
     
         4 . The method of  claim 1 , including the step of observing the electrical signal at fifteen seconds or more after the sensor makes contact with the vessel wall.  
     
     
         5 . The method of  claim 1 , including the step of observing the electrical signal at twenty seconds or more after the sensor makes contact with the vessel wall.  
     
     
         6 . The method of  claim 1 , further including the step of occluding blood flow before determining the temperature of the vessel wall.  
     
     
         7 . The method of  claim 1 , further including the steps of: 
 occluding blood flow after determining the temperature of the vessel wall; and    determining a subsequent temperature of the vessel wall using the instrumentation by observing the electrical signal several seconds following the occlusion.    
     
     
         8 . The method of  claim 7 , including the step of observing the electrical signal at five seconds or more after occluding blood flow.  
     
     
         9 . The method of  claim 7 , including the step of observing the electrical signal at ten seconds or more after occluding blood flow.  
     
     
         10 . The method of  claim 7 , including the step of observing the electrical signal at fifteen seconds or more after occluding blood flow.  
     
     
         11 . The method of  claim 7 , including the step of observing the electrical signal at twenty seconds or more after occluding blood flow.  
     
     
         12 . A method of determining whether a point on the wall of a blood vessel exhibits an elevated temperature, comprising the steps of: 
 contacting the point with a temperature sensor;    measuring the temperature of the point at least a few seconds after making contact to obtain a first temperature reading;    occluding blood flow through the vessel;    measuring the temperature of the same point at least a few seconds after the blood flow is occluded to obtain a second temperature reading; and    comparing the first and second temperature readings to determine whether the temperature of the point is elevated.    
     
     
         13 . The method of  claim 12 , further including the step of choosing an alternative therapeutic technique in the event the temperature is elevated.  
     
     
         14 . The method of  claim 12 , wherein the therapeutic technique involves the selection of a stent to minimize restenosis.  
     
     
         15 . The method of  claim 14 , wherein the selection includes a choice between a drug-coated versus non-drug-coated stent.