An aneurysmal sac arterial wall electrostimulation system (11) comprises an array of electrical leads (4 and 5) placeable in contact with a portion of the arterial wall (12) to be electrostimulated and a source (3) of electrostimulation attached to the array of electrical leads. The source provides periodic electrostimulus to at least one of the array of leads in accordance with a treatment program and at least one of the array of leads senses the contraction condition of the aneurysmal sac arterial wall (10) which is provided as a feedback loop input signal to the treatment program. Repeated electrostimulation of a vascular passage using the system (11) provides increased muscle tone or pseudo permanent contraction of such vascular passage.