Active Versus Passive Thaw After Percutaneous Cryoablation of Pulmonary Tumors: Effect on Incidence, Grade, and Onset of Hemoptysis

BACKGROUND. Hemoptysis is common after percutaneous image-guided cryoablation of pulmonary tumors. OBJECTIVE. The purpose of our study was to evaluate the effect of a final active thaw on the incidence, grade, and onset of hemoptysis after percutaneous cryoablation of pulmonary tumors. METHODS. This retrospective cohort study included 60 consecutive CT-guided cryoablation sessions targeting 95 pulmonary tumors in 47 patients from March 2017 to September 2020. The final thaw of a triple-freeze protocol was active (electrical, helium-free) in 27 of 60 sessions (45%, active group) and passive in 33 of 60 sessions (55%, passive group). The incidence, onset, and management of hemoptysis were recorded using prospectively collected data. Hemoptysis, pneumothorax, and hemothorax within 30 days after ablation were graded according to Common Terminology Criteria for Adverse Events (CTCAE) version 5.0. The volume of immediate posttreatment changes on CT was quantified using semiautomated segmentation. Outcomes were compared between groups using generalized estimating equation models. A parsimonious multi-variable model for hemoptysis incidence was developed using purposeful selection of predefined covariates followed by bootstrap resampling. Local tumor control was compared between groups using the Kaplan-Meier method and log-rank testing. RESULTS. Hemoptysis occurred after 26 of 60 (43%) sessions and was self-limited (CTCAE grade 1) in 22 of 26 (85%) sessions. The incidence of hemoptysis was lower in the active group than in the passive group (19% vs 64%, respectively; p = .002). The odds of hemoptysis adjusted for immediate posttreatment changes were 92% lower in the active group (odds ratio [OR], 0.08 [95% CI, 0.02- 0.37]; p = .004). The odds of hemoptysis greater than grade 1 were 79% lower in the active group (OR, 0.21 [95% CI, 0.07-0.64]; p = .006). In the active group, the onset of hemoptysis was significantly delayed (OR, 0.75 [95% CI, 0.61-0.91]; p = .005). Pneumothorax (p = .60), hemothorax (p = .84), and local tumor control (p = .77) did not differ between groups. CONCLUSION. Active thaw after the final freeze reduces the incidence and grade of hemoptysis and delays the onset of hemoptysis after percutaneous cryoablation of pulmonary tumors without adversely affecting other procedural complications and local tumor control. CLINICAL IMPACT. Active thaw after the final freeze improves the safety profile of triple-freeze cryoablation of pulmonary tumors by reducing the incidence and grade of hemoptysis and by delaying the onset of hemoptysis beyond the immediate recovery period.