During coronary balloon angioplasty (PTCA), arterial wall injury is unavoidable. This injury could give rise to local inflammation, accounting for increased thrombogenicity and hyperplasia. Coronary thermography is a new method that aims to detect the inflamed areas on the arterial wall by tracing the heat signatures of the activated macrophages. The temperature traces below were observed in a non-atherosclerotic pig, during a 60 mm automatic pullback of a thermographic catheter. The catheter (Thermocore Medical Ltd, UK) has four temperature sensors and an accuracy of 0.01°C. The pullback was performed in the middle segment of the right coronary artery, with a speed of 0.3 mm/s. A 3.0 20 mm balloon (Crossail, Guidant Inc, USA) was inflated in this area for 30 seconds, at 12 atm. The arterial wall temperature was re-scanned immediately after the inflation, after four days and then finally after 10 days. The four colour lines in each recording represent the signal of the four thermal sensors.

Recording A was obtained before the balloon inflation. The temperature of the area of interest (AOI) was stable (ΔT< 0.01°C, p = ns) and equal to the temperature of the neighbouring areas. Recording B was obtained immediately after the balloon inflation. Temperature appeared lower in the AOI, since the balloon was inflated using contrast media at room temperature. Recording C was obtained four days after the initial inflation. The AOI was significantly warmer (ΔT 0.12°C, p < 0.001) than the non-injured areas. Recording D was obtained 10 days after the balloon inflation. The previously observed temperature heterogeneity had disappeared. This temperature effect can be explained by the local inflammation that follows the wall injury.