Although ex vivo studies showed marked thermal heterogeneity in atheromatic plaques, in in vivo human studies trivial temperature variations are recorded due to the cooling effect of blood flow. We investigated a new balloon-thermogaphy catheter for temperature measurements during coronary flow interruption. A thermistor probe is positioned at the distal segment of the catheter. At the opposite site of the thermistor, a balloon is placed. By inflation of the balloon, coronary flow is interrupted. Ten patients with effort angina were studied. Coronary flow velocity was continuously recorded. Temperature was recorded at the proximal vessel wall and at the lesion before, during, and after complete interruption of blood flow by inflation of the balloon. DeltaTp was assigned as the difference between the background temperature and the maximal temperature during and after balloon inflation. DeltaTl was assigned as the difference between the atherosclerotic plaque and the proximal vessel wall. The procedure was not complicated. DeltaTp during and after balloon inflation was 0.01 +/- 0.01 degrees C and -0.003 +/- -0.01 degrees C (P < 0.001), respectively. DeltaTl was 0.07 +/- 0.04 degrees C at baseline, 0.17 +/- 0.06 degrees C (59.3% +/- 11.8% increase) during, and 0.07 +/- 0.05 degrees C after flow interruption (P < 0.001). DeltaTl was greater than DeltaTp during and after impairment of flow (P < 0.001). In vivo atherosclerotic plaque temperature recording seems to be feasible with this new balloon-thermography catheter. This device may introduce a new approach for the detection of thermal heterogeneity in plaques by addressing the issue of cooling effect of blood flow.
Copyright 2003 Wiley-Liss, Inc.