A kit for use in cryoablation procedures includes a cryoablation catheter having a cryoballoon positioned about its distal region. A pressure sensor is positioned distally of the cryoballoon. The catheter can be introduced into a patient's left atrium and the cryoballoon inflated. The cryoballoon can then be advanced into contact with a pulmonary vein wall in a manner that occludes the pulmonary vein. Occlusion can be verified by measuring a pressure within the pulmonary vein. Once occlusion is verified, the cryoballoon can be cooled to form a circumferential lesion about the pulmonary vein.