An ablation catheter system comprising a catheter shaft (534; 734) including proximal and distal ends, a dual cryogenic ablation balloon (536; 736) coupled to the distal end of the catheter shaft (534; 734), the dual cryogenic ablation balloon including an inner balloon (554; 754) and an outer balloon (555; 755), an interstitial space (557; 757) between the inner and outer balloons configured and arranged to capture cryogenic fluid that escapes from an internal cavity of the inner balloon (554; 754), a manifold configured and arranged to deliver cryogenic fluid to the internal cavity of the inner balloon (554; 754), a first and second lumen (558 A, 558 B; 758 A; 758 B) in fluid communication with the interstitial space (557; 757), and an adaptor (530; 730) that mechanically couples the inner and outer balloons (554, 555; 754, 755) to the catheter shaft (534; 734), and radially and longitudinally offsets proximal portions of the inner and outer balloons (554, 555; 754, 755), wherein the first lumen (558 A; 758 A) is configured and arranged to draw a vacuum within the interstitial space (557; 757) and to draw captured cryogenic fluid out of the interstitial space (557; 757), the second lumen (558 B; 758 B) is configured and arranged to sense a change in vacuum pressure within the interstitial space (557; 757) associated with a flow of cryogenic fluid through the inner balloon (554; 754), and the system further includes a spacer coupled between said proximal portions of the inner and outer balloons (554, 555; 754, 755), the spacer configured and arranged to maintain the interstitial space (557; 757) between the inner and outer balloons (554, 555; 754, 755) in response to a vacuum pressure within the interstitial space, the spacer includes a plurality of channels that extend into an inner diameter and along a length of the spacer, the plurality of channels are configured and arranged to facilitate the flow of a fluid between the interstitial space (557; 757), the first lumen (558 A; 758 A), and the second lumen (558 B; 758 B). a catheter shaft (534; 734) including proximal and distal ends, a dual cryogenic ablation balloon (536; 736) coupled to the distal end of the catheter shaft (534; 734), the dual cryogenic ablation balloon including an inner balloon (554; 754) and an outer balloon (555; 755), an interstitial space (557; 757) between the inner and outer balloons configured and arranged to capture cryogenic fluid that escapes from an internal cavity of the inner balloon (554; 754), a manifold configured and arranged to deliver cryogenic fluid to the internal cavity of the inner balloon (554; 754), a first and second lumen (558 A, 558 B; 758 A; 758 B) in fluid communication with the interstitial space (557; 757), and an adaptor (530; 730) that mechanically couples the inner and outer balloons (554, 555; 754, 755) to the catheter shaft (534; 734), and radially and longitudinally offsets proximal portions of the inner and outer balloons (554, 555; 754, 755), wherein the first lumen (558 A; 758 A) is configured and arranged to draw a vacuum within the interstitial space (557; 757) and to draw captured cryogenic fluid out of the interstitial space (557; 757), the second lumen (558 B; 758 B) is configured and arranged to sense a change in vacuum pressure within the interstitial space (557; 757) associated with a flow of cryogenic fluid through the inner balloon (554; 754), and the system further includes a spacer coupled between said proximal portions of the inner and outer balloons (554, 555; 754, 755), the spacer configured and arranged to maintain the interstitial space (557; 757) between the inner and outer balloons (554, 555; 754, 755) in response to a vacuum pressure within the interstitial space, the spacer includes a plurality of channels that extend into an inner diameter and along a length of the spacer, the plurality of channels are configured and arranged to facilitate the flow of a fluid between the interstitial space (557; 757), the first lumen (558 A; 758 A), and the second lumen (558 B; 758 B).