Vulnerable plaque detection by temperature heterogeneity measured with a guidewire system: clinical, intravascular ultrasound and histopathologic correlates.

Diagnosing plaque vulnerability may have therapeutic and prognostic implications. We used a heat sensor-tipped thermography guidewire to identify temperature variations in atherosclerotic coronary arteries in patients undergoing stent placement. This study is the first human experience with the ThermoCoil Guidewire (TG). TG consists of a 0.014 inch wire which rotates as it is retracted so as to interrogate the arterial lumen in a helical path. The wire has a temperature sensor in the distal tip with a sensitivity of 0.03 degrees Celcius. In 13 patients presenting with either acute or chronic coronary syndromes as indications for percutaneous coronary intervention, the following parameters were assessed: thermography, intravascular ultrasound (IVUS), angiography and serum markers for inflammation (C-reactive protein) and ischemia (troponin). Directional atherectomy was performed in 2 patients and tissue was analyzed histopathologically. Two patients had unstable angina, 2 had myocardial infarction, and 9 had stable angina as indications for coronary intervention. There were no device-related adverse events or system failures. Thermography was performed on all patients prior to any other intervention. Intra-arterial temperature rises between 0.1 degrees Celcius and 0.3 degrees Celcius were noted in 4 subjects. Intravascular ultrasound findings and atherectomy tissue histology showed correlates of plaque vulnerability in plaques with elevated temperature. In conclusion, thermography using a guidewire-based system can be performed safely, and detected lesions whose IVUS and/or atherectomy findings suggested plaques at high risk for rupture. Further studies will determine the predictive value of thermography or other techniques for assessing plaque composition and risk through noninvasive or invasive means.