A guide catheter includes an outer guide having an open lumen and a longitudinal pre-stress line extending between a distal end and a proximal end of the outer guide. The heat sink has heat dissipating fins extending from at least a portion of a surface of the heat sink, other than a connecting face thermally connected to the heat source. Outlier values are identified by selecting values outside of a selected sliding window of data having the lowest variance. A characteristic length is assigned to the base element.