Objective--Safety and feasibility evaluation of intracoronary temperature measurements in patients with acute coronary syndromes (ACS) using a catheter based thermography system.

Methods and Results--Thermography was performed in 40 patients with ACS. A 3.5-F thermography catheter containing 5 thermocouples measuring vessel wall temperature, and 1 thermocouple measuring blood temperature (accuracy 0.05°C) was used. Gradient (Tmax) between blood temperature (T_bl) and the maximum wall temperature during pullback was measured. The device showed satisfactory safety in ACS. Only in 16 patients (40%) Tmax was 0.1°C. In 23 patients (57.5%) the highest Tmax was found in the culprit segment. Tmax between culprit and adjacent non-culprit segments was observed in patients with transient blood flow interruption during thermography (0.11±0.03 versus 0.08±0.01; P=0.04), in contrast to patients with preserved flow (0.07±0.03 versus 0.06±0.02; P=0.058).

Conclusions--The novel, technically sophisticated intracoronary thermography proved its safety and feasibility. However, we were not able to convincingly and consistently differentiate between different lesions at risk, despite a selection of lesions that should appear most distinct to differentiate. A systematic interruption of flow may be necessary to achieve diagnostic results consistently, although such requirement may unfavorably change the risk-to-benefit ratio of this developing technology.