Apparatus and methods for uniformly distributing coolant within a cryo-ablation device. A nozzle apparatus includes a tubular member having a plurality of angled apertures that induce swirling of coolant streams dispersed through the angled apertures. Coolant swirling round the tubular member and along an inner surface of an inflatable balloon element inflates the balloon element and cryogenically ablate tissue. The swirling action achieved using angled apertures uniformly distributes coolant along the inner surface of the balloon such that the temperatures along an inner surface of the balloon element and ablation of tissue adjacent to the balloon element are substantially uniform.
