Associations of Pleural Puncture Angle and Other Factors With Major Adverse Events After Thermal Lung Tumor Ablation: A Two-Center Study

Background: Applicator insertion parallel to the bronchovascular bundle has been recommended for percutaneous ablation of central lung tumors. However, the relationship between the applicator insertion angle and adverse events remains understudied. Objective: To examine associations of the pleural puncture angle and other factors with major adverse events following percutaneous ablation of lung tumors. Methods: This retrospective study included consecutive patients who underwent percutaneous cryoablation or microwave ablation (MWA) of lung tumors at two academic medical centers between February 2008 and April 2023. A reader measured the pleural puncture angle on intraprocedural CT images. A second reader independently performed measurements in a subset to assess interreader agreement. Sessions were classified as central if at least one targeted tumor was located >4 cm from the costal pleura and as noncentral otherwise. The relationship between major adverse events and the pleural puncture angle was evaluated by separate multivariable logistic regression models for central and noncentral sessions; models also included modality (cryoablation vs MWA), number of pleural punctures (<3 vs ≥3), applicator path through lung parenchyma, and maximum applicator gauge. Results: The analysis included 260 patients (152 women, 108 men; median age, 65 years) who underwent 416 sessions (299 cryoablation procedures, 117 MWA procedures; median pleural puncture angle, 57°) targeting 638 tumors. Interreader agreement for pleural puncture angle in 100 randomly selected cases was excellent (intraclass correlation coefficient=0.94). A total of 86 (21%) sessions were classified as central, and 330 (79%) as noncentral. Major adverse events occurred after 37 (9%) sessions. In multivariable analyses, for central sessions, major adverse events were independently associated only with pleural puncture angle (OR per degree=0.94; p=.01); in noncentral sessions, major adverse events were independently associated with MWA (OR=2.98; p=.03) and ≥3 pleural punctures (OR=3.75; p=.004), but not other factors including pleural puncture angle. Conclusion: When targeting central tumors, steeper pleural puncture angles were associated with fewer major adverse events. When targeting noncentral tumors, use of MWA and ≥3 pleural punctures were associated with increased major adverse events. Clinical Impact: The findings support applicator insertion with a steep pleural puncture angle during percutaneous ablation of central lung tumors.