PURPOSE:Cryospray ablation (CSA) is a non-contact method of destroying unwanted tissue using low-pressure liquid nitrogen. The rapid freezing and thawing of CSA evokes acute and chronic hemostatic effects and intracellular damage, leading to regeneration of healthy tissue. Prior studies of CSA in the airway of swine suggested safety and feasibility for thoracic applications in humans. This is the first study of CSA in human airways.
METHODS:CSA was administered in healthy airway tissue of 15 subjects during a standard bronchoscopy prior to lung resection. Group 1 (n=3) received same day therapy, Group 2 (n=2) 2–4 days, Group 3 (n=3) 5–7 days, and Group 4 (n=2) 8+ days, prior to lobectomy. All groups received 2 cycles of 5 second spray dosimetry with a 60 second interim thaw. Oxygen saturation and peak airway pressure were monitored constantly. Subjects received 100% oxygen through out the procedure. Histological inspection of the resected specimen was preformed by a blinded pathologist.
RESULTS:No adverse events or were reported. 4 of the 15 subjects did not undergo resection. Histologic examination of Groups 1 and 2 revealed loss of epithelium and muscularis mucosa, edema, and damaged sub-mucosal glands. Group 3 revealed areas of denuded mucosa at the treatment site, but showed adjacent re-epithelialization, although edema and loss of smooth muscle and glands were still evident. One specimen in Group 4 showed complete re-epithelialization and normalization of tissue except some residual edema and some permanent loss of smooth muscle. Depth of cryo-necrosis in all groups was limited to the mucosal and submucosal layers (∼.5mm), with no evidence of connective tissue injury. There was no evidence of scarring in any of the airways examined.
CONCLUSION:The results of this trial demonstrate the safety and efficacy of CSA in the human airway. Further studies should be conducted to determine CSA's ability to destroy additional malignant and benign diseases in humans.
CLINICAL IMPLICATIONS:CSA shows promise for a broad range of lung diseases.
DISCLOSURE:William Krimsky, University grant monies No; Grant monies (from sources other than industry) No; Grant monies (from industry related sources) No; Shareholder No; Employee No; Fiduciary position (of any organization, association, society, etc, other than ACCP No; Consultant fee, speaker bureau, advisory committee, etc. Consultant–Chair of Scientific Advisory Board; Other No; No Product/Research Disclosure Information