Method and system for assessing severity and stage of peripheral arterial disease and lower extremity wounds using angiosome mapping

Abstract

The present invention provides a system for assessing the severity and stage of PAD including at least one sensor that measures skin perfusion pressure; a knowledge base that provides data on lower extremity angiosomes; and a processing device in operable communication with the sensor and the knowledge base, the processing device that outputs a visual representation of at least one of the lower extremity angiosomes that guides the sensor in the mapping of a testing site relative to a target vessel where the skin perfusion pressure measurement will be taken.

What is claimed is: 
     
         1 . An angiosome-based system for monitoring and assessing lower extremity disease comprising:
 a compression device sized and shaped for placement on a lower extremity limb of a patient, the compression device including a pressure cuff configured to exert a compressive force on said lower extremity limb, the compressive force configured to substantially occlude blood flow in a skin capillary bed adjacent said pressure cuff, said skin capillary bed located in a lower extremity angiosome;   at least one sensor positioned adjacent said pressure cuff, said at least one sensor for measuring peripheral vascular conditions of the patient in the skin capillary bed and configured to generate a signal indicative of the peripheral vascular condition;   a processing device in operable communication with said at least one sensor, said processing device configured to (a) output a visual representation of said lower extremity angiosome, said visual representation to guide the placement of said sensor in the mapping of a testing site relative to said skin capillary bed; (b) receive a peripheral vascular measurement based on said angiosome mapping; and (c) output data that is indicative of lower extremity disease based on said angiosome mapping.   
     
     
         2 . The system of  claim 1  wherein said peripheral vascular conditions include at least one of skin perfusion pressure, pulse volume recordings, transcutaneous oxygen monitoring, ankle brachial index, tissue CO2, temperature, spectral imaging, and hyperspectral imaging. 
     
     
         3 . The system of  claim 1  wherein said at least one sensor comprises a pulse oximetry sensor. 
     
     
         4 . The system of  claim 1  further comprising a knowledge base that provides normative data on said at least one lower extremity angiosome, said processing device in operable communication with said knowledge base. 
     
     
         5 . The system of  claim 4  wherein said processing device is further configured to cross reference said peripheral vascular measurement with said knowledge base to generate a cross referenced data result indicative of the severity and stage of the lower extremity disease. 
     
     
         6 . The system of  claim 1  further comprising a knowledge base of disease scoring and/or classification systems and a knowledge base of peripheral arterial disease and lower extremity wounds, wherein said processing device is further configured to cross reference said peripheral vascular measurement with said knowledge base of disease scoring and/or classification systems and said knowledge base of peripheral arterial disease and lower extremity wounds to generate a combined cross referenced data result indicative of the severity and stage of lower extremity disease and further wherein said processing device outputs data that is indicative of the severity and stage of lower extremity disease based on said combined cross referenced data result. 
     
     
         7 . The system of  claim 1  further comprising at least one metabolic sensor for measuring at least one metabolic condition of the patient, wherein said processing device is arranged to receive inputs from said at least one metabolic sensor. 
     
     
         8 . The system of  claim 1  further comprising at least one skin perfusion sensor for measuring skin perfusion. 
     
     
         9 . The system of  claim 1  further comprising:
 an inflatable cuff, wherein said at least one sensor is a skin perfusion measurement sensor in communication with the cuff; 
 a pressure sensor in communication with the cuff for reading pressure levels in the cuff; 
 a pressure instrument in fluid communication with the cuff for inflation and deflation thereof, the pressure instrument comprising:
 a source of pressurized air; and 
 a conduit connected to the source of pressurized air and the cuff, thereby placing the source of pressurized air in fluid communication with the cuff, wherein said processing device is operably coupled to said pressure instrument and capable of controlling pressurized airflow to and from the cuff, and further wherein said processing device is arranged to receive inputs from said skin perfusion measurement sensor and said pressure sensor; 
 a computer program executable by the processing device such that when executed, the computer program causes the processing device to:
 initiate an automatic inflation sequence resulting in a no flow condition; initiate an automatic deflation sequence; 
 automatically qualify a perfusion measurement as a skin perfusion pressure value upon all conditions of a set of predetermined conditions being met during the deflation sequence; 
 
 
 wherein said processing device receives said skin perfusion pressure value based on said angiosome mapping, and cross references said skin perfusion pressure value with said knowledge base to generate a cross referenced data result indicative of said severity and stage of lower extremity disease. 
 
     
     
         10 . An angiosome-based perfusion monitoring system for peripheral artery disease, the monitoring system comprising:
 a control device including a source of pressurized fluid for introducing into a compression device that is placed on a limb of a subject; and   a control circuit configured to (i) pressurize at least one bladder of a compression device when the compression device is placed on a limb of a subject to substantially occlude blood perfusion in skin capillary beds adjacent to the at least one bladder, (ii) depressurize the at least one bladder at a controlled rate after pressurizing the bladder, (iii) receive a sensor signal from at least one perfusion sensor on the compression device during depressurization of the at least one bladder, wherein the sensor signal is indicative of perfusion parameters of at least one skin capillary bed adjacent said at least one perfusion sensor for quantifying skin capillary bed perfusion, and (iv) map sensor signals from said at least one perfusion sensor to at least one of a first angiosome and at least one artery of the limb to determine whether the received sensor signal is indicative of peripheral artery disease.   
     
     
         11 . The monitoring system of  claim 10 , wherein the control device is configured to determine at least one of: adequate perfusion, no flow, baseline flow, skin perfusion pressure value, and return of microcirculation based on the received sensor signals. 
     
     
         12 . The monitoring system of  claim 10 , wherein the control device is configured to determine skin perfusion pressure value based on the received sensor signals and compare the skin perfusion pressure value to a threshold value to determine whether the received sensor signals are indicative of peripheral artery disease. 
     
     
         13 . The monitoring system of  claim 10 , wherein the control device is configured to determine the baseline flow and the return of microcirculation based on the received sensor signals and determine a time elapsed between the baseline flow and the return of microcirculation to determine whether the received sensor signals are indicative of peripheral artery disease. 
     
     
         14 . The monitoring system of  claim 10 , wherein the control device comprises a user interface display, wherein the control circuit is configured to generate a graphical rendering of the limb and identify on the graphical rendering the location of the determined peripheral artery disease. 
     
     
         15 . A method of monitoring for peripheral artery disease, the method comprising:
 pressurizing a bladder of a compression device that is placed on a limb of a wearer so as to substantially occlude blood perfusion to skin capillary beds adjacent the bladder of the compression device;   depressurizing the bladder at a controlled rate after said pressurizing the bladder;   detecting, during said depressurizing the bladder and using at least one sensor, a perfusion parameter of a skin capillary bed located in at least one angiosome of the limb;   generating a sensor signal indicative of the perfusion parameter detected by said at least one sensor;   receiving, by a control circuit, said at least one sensor signal;   mapping, by the control circuit, said at least one sensor signal to at least one of the first angiosome and a first artery associated with the first angiosome; mapping, by the control circuit, the second sensor signal at least one of said angiosome; and   determining, by the control circuit, whether the first and second sensor signals are indicative of peripheral artery disease.   
     
     
         16 . The method of  claim 15 , further comprising determining, by the control circuit, at least one of: adequate perfusion, no flow, baseline flow, skin perfusion pressure value, and return of microcirculation based on the received sensor signals. 
     
     
         17 . The method of  claim 16 , further comprising determining, by the control circuit, skin perfusion pressure value based on the received sensor signals and comparing the skin perfusion pressure value to a threshold value to determine whether the received sensor signals are indicative of peripheral artery disease. 
     
     
         18 . The method of  claim 16 , further comprising determining, by the control circuit, the baseline flow and the return of microcirculation based on the received sensor signals, and calculating, by the control circuit, a time elapsed between the baseline flow and the return of microcirculation for use in determining whether the received sensor signals are indicative of peripheral artery disease.