Temperature monitoring during peripheral thermo‐optical laser recanalization in humans

To determine probe temperature required to achieve laser thermal recanalization of human peripheral arteries, temperature was monitored at the probe tip using a K‐type thermocouple and displayed on a computer screen in real‐time in 21 procedures. Recanalization was performed using a Spectraprobe‐PLR delivering both laser light and heat in patients with prolonged ischemic limb symptoms. Laser recanalization of totally occluded peripheral arteries (occlusion length = 5.3 ± 3.8 cm) was done percutaneously (17 procedures) or intraoperatively (4 procedures), after unsuccessful attempts of recanalization using standard guide wire and balloon angioplasty techniques. Probes were activated using argon laser irradiation starting at 5 W and increased by 1‐W increments until successful recanalization, or up to a maximum of 12 W. Laser recanalization was achieved in 16/21 (76%) procedures at a mean temperature of 178±120° (range 64–503°) and a mean time of 12.4±14.1 s. Eleven of the 16 (69%) recanalizations occurred at probe temperature lower than 160°. Recanalization was achieved at a mean power of 7±2 W. Perforation occurred in 6 arteries at peak probe temperatures ranging from 73 to 502°. Perforations occurred in 4 of 6 densely calcific vessels which required high probe temperatures (>250°). An important feature of temperature monitoring was the immediate detection of probe dysfunction. Although recanalization temperature had a wide range, the majority of recanalizations occurred at probe temperature below 160°. Initial use of low laser power irradiation and low temperature with incremental rises seems to be a rational strategy when attempting recanalization of totally occluded peripheral arteries. Perhaps this strategy will prevent complications related to high probe temperature.