Intravascular thermography: Immediate functional and morphological vascular findings

Aim: To investigate safety, feasibility, and injurious effect on endothelial cells of a thermography catheter as well as effect of flow on measured temperature in nonobstructive arteries. Methods and results: Safety and feasibility were tested in both rabbit aortas and pig coronary arteries. Evaluation of endothelial damage by the catheter (acute, 7 and 14 days) was performed in pig coronaries using Evans Blue, scanning electron microscopy (SEM) and Factor-VIII antibody and compared with normal arteries and arteries that underwent intravascular ultrasound (IVUS). The effect of flow on temperature heterogeneity was analysed both in vitro and in vivo conditions. All procedures were successful without any adverse events; intra- and inter-operator variability was low. Intracoronary use of the catheter was associated with acute but reversible de-endothelialization, paralleling the findings associated with IVUS use. Changes in flow velocities under physiologic flow conditions did not significantly influence the temperature differences measured both in vitro and in vivo; temperature heterogeneity was more pronounced in absence of flow. Conclusion: Intracoronary thermography using a dedicated catheter is safe and feasible with a similar degree of de-endothelialization as IVUS. Temperature heterogeneity remained unchanged under normal physiologic flow conditions allowing clinical use of thermography.