A catheter for carotid artery dilatation that includes a multi-chamber balloon assembly mounted at the distal end of the elongated tube that has at least two tandem chambers. Each chamber communicates with a separate lumen and each separate lumen terminates at the proximal end at a lumen valve head. The chambers have an inflated configuration with a diameter that progressively tapers in a direction from proximal to distal, said taper extends substantially continuously from the proximal end of the balloon assembly to the distal end thereof.