A balloon comprising: a center portion having a proximal end, a distal end opposite the proximal end, and a length between the proximal end and the distal end. The center portion comprises: a first nominal diameter and a first radial modulus at the proximal end; a second nominal diameter and a second radial modulus at the distal end; further wherein, the first nominal diameter is equal to the second nominal diameter, such that, when the balloon is inflated to a nominal pressure, the center portion has a constant diameter over the length; and further wherein, the first radial modulus is smaller than the second radial modulus, such that, when the balloon is inflated above a nominal pressure, the center portion adopts a tapered shape in which the proximal end has a first stretched diameter and the distal end has a second stretched diameter, the first stretched diameter being larger than the second stretched diameter.