Method and apparatus for location and temperature specific drug action such as thrombolysis

Abstract

A method is provided of localizing a drug action where the drug is present throughout a vascular system. The localization occurs to within a volume of blood in a blood vessel, the vascular system having an initial temperature substantially within a first temperature range. A temperature-specific enzyme is delivered throughout a vascular system including a volume of blood in a blood vessel, the temperature-specific enzyme having a working temperature within a prespecified temperature range that does not substantially overlap the first temperature range. A heat transfer element is delivered to a blood vessel in fluid communication with the volume of blood. The temperature of the heat transfer element is adjusted such that the volume of blood in the blood vessel is heated or cooled to the prespecified temperature range. In this way, the action of the temperature-specific enzyme is substantially limited to the volume of blood heated or cooled. In an alternative embodiment, the temperature-specific enzyme is localized to the volume of blood in the blood vessel, and the heat transfer element is disposed in fluid communication with the volume of blood in the blood vessel. The enzyme localization may occur by way of direct injection or by way of injection through a lumen of a catheter. The injection lumen of the catheter may be disposed at least partially adjacent or in combination with the heat transfer element and its associated inlet and outlet lumens.

What is claimed is:  
     
         1 . A method of localizing a drug action, the drug present throughout a vascular system, the localization occurring to within a volume of blood in a blood vessel, the vascular system having an initial temperature substantially within a first temperature range, comprising: 
 delivering a temperature-specific enzyme throughout a vascular system including a volume of blood in a blood vessel, the temperature-specific enzyme having a working temperature within a prespecified temperature range that does not substantially overlap the first temperature range;    delivering a heat transfer element to a blood vessel in fluid communication with the volume of blood; and    adjusting the temperature of the heat transfer element such that the volume of blood in the blood vessel is heated or cooled to the prespecified temperature range,    such that the action of the temperature-specific enzyme is substantially limited to the volume of blood heated or cooled.    
     
     
         2 . The method of    claim 1   , wherein the adjusting includes inducing turbulence in the blood to enhance a heat transfer rate.  
     
     
         3 . The method of    claim 2   , wherein the adjusting further includes inducing turbulence in a working fluid flowing through the heat transfer element.  
     
     
         4 . A method for selective drug therapy by selective vessel hypothermia in a vascular system having an average blood temperature at a first temperature, comprising: 
 introducing a catheter having a heat transfer element into a blood vessel in fluid communication with a blood vessel requiring drug therapy in a vascular system having an average blood temperature at a first temperature;    cooling the heat transfer element by flowing a working fluid through the heat transfer element;    cooling the blood by flowing the blood past the heat transfer element and inducing mixing in the blood, such that the blood is cooled from the first temperature to a prespecified temperature range; and    delivering a drug to the blood, the drug having a working temperature within the prespecified temperature range.    
     
     
         5 . A method for selective drug therapy by selective vessel hyperthermia in a vascular system having an average blood temperature at a first temperature, comprising: 
 introducing a catheter having a heat transfer element into a blood vessel in fluid communication with a blood vessel requiring drug therapy in a vascular system having an average blood temperature at a first temperature;    heating the heat transfer element by flowing a working fluid through the heat transfer element;    heating the blood by flowing the blood past the heat transfer element and inducing mixing in the blood, such that the blood is heated from the first temperature to a prespecified temperature range; and    delivering a drug to the blood, the drug having a working temperature within the prespecified temperature range.    
     
     
         6 . A method of localizing a drug action to substantially within a volume of blood in a blood vessel, the vascular system having an initial temperature substantially within a first temperature range, comprising: 
 delivering a temperature-specific enzyme to a volume of blood in a blood vessel, the temperature-specific enzyme having a working temperature within a prespecified temperature range that does not substantially overlap the first temperature range;    delivering a heat transfer element to a blood vessel in fluid communication with the volume of blood; and    adjusting the temperature of the heat transfer element such that the volume of blood in the blood vessel is heated or cooled to the prespecified temperature range,    such that the action of the temperature-specific enzyme is substantially limited to the volume of blood heated or cooled.    
     
     
         7 . The method of    claim 6   , wherein the delivering includes injecting the temperature-specific enzyme intravenously.  
     
     
         8 . The method of    claim 6   , wherein the delivering includes injecting the temperature-specific enzyme through a lumen adjacent the heat transfer element.  
     
     
         9 . The method of    claim 6   , wherein the delivering includes injecting the temperature-specific enzyme through a tip of the heat transfer element.  
     
     
         10 . The method of    claim 4   , wherein the delivering includes injecting the drug intravenously.  
     
     
         11 . The method of    claim 4   , wherein the delivering includes injecting the drug through a lumen adjacent the heat transfer element.  
     
     
         12 . The method of    claim 4   , wherein the delivering includes injecting the drug through a tip of the heat transfer element.  
     
     
         13 . The method of    claim 5   , wherein the delivering includes injecting the drug intravenously.  
     
     
         14 . The method of    claim 5   , wherein the delivering includes injecting the drug through a lumen adjacent the heat transfer element.  
     
     
         15 . The method of    claim 5   , wherein the delivering includes injecting the drug through a tip of the heat transfer element.  
     
     
         16 . The method of    claim 4   , wherein the drug is a neuroprotectant.  
     
     
         17 . The method of    claim 5   , wherein the drug is a neuroprotectant.  
     
     
         18 . The method of    claim 4   , wherein the drug is tPA.  
     
     
         19 . The method of    claim 5   , wherein the drug is tPA.