The RADI PressureWire high-sensitivity thermistor and culprit lesion temperature in patients with acute coronary syndromes.

Background. Patients with acute coronary syndromes (ACS) have been shown to have a local increase in culprit lesion temperature of at least 0.5°C using a specialized thermography catheter. However, this device is unique, not clinically available and unable to provide information other than temperature. The 0.014-inch Radi" PressureWire® XT (RPW) contains a high-sensitivity thermistor in the sensor that has a sensitivity of 0.1°C. We evaluated the ability of the RPW to detect an increase in plaque temperature in patients with ACS. Methods and Results. Patients with ACS and a culprit lesion of > 70% stenosis and who were candidates for percutaneous coronary intervention (PCI) were eligible (n = 20). Fractional flow reserve (FFR) post-adenosine administration and temperature estimations were performed prior to PCI. All demographic data are presented as mean ± SD, and temperature data (using delta temperature from baseline) as mean ± SEM. Fifteen men and 5 women were enrolled (age 59.5 ± 11.6 years). The FFR pre-PCI was 0.65 ± 0.06, consistent with hemodynamically significant stenoses. The baseline delta temperature was 0.00 ± 0.01°C. The delta temperature at the culprit lesion was -0.02 ± 0.01°C (p = NS), a result below the resolution of the thermistor. Post-PCI, the FFR was 0.95 ± 0.01 (p < 0.0001). Conclusions. The RPW was unable to detect any temperature increase in patients with ACS.