Apparatus (20) is provided, including a bifurcation stent (50) comprising one or more electrodes (32), the stent (50) configured to be placed in a primary passage (52) and a secondary passage (54) of a blood vessel (30), and a control unit (34), configured to drive the electrodes (32) to apply a signal to a wall (36) of the blood vessel (30), and to configure the signal to increase nitric oxide (NO) secretion by the wall (36). Other embodiments are also described.
