title: Pulmonary Microwave Ablation Near the Heart: Antenna Positioning Can Mitigate Cardiac Complications in a Porcine Model.
abstract: Purpose To determine how close to the heart pulmonary microwave ablation can be performed without causing cardiac tissue injury or significant arrhythmia. Materials and Methods The study was performed with approval from the institutional animal care and use committee. Computed tomographic fluoroscopically guided microwave ablation of the lung was performed in 12 swine. Antennas were randomized to either parallel (180° ± 20°) or perpendicular (90° ± 20°) orientation relative to the heart surface and to distances of 0-10 mm from the heart. Ablations were performed at 65 W for 5 minutes or until a significant arrhythmia (asystole, heart block, bradycardia, supraventricular or ventricular tachycardia) developed. Heart tissue was evaluated with vital staining and histologic examination. Data were analyzed with mixed effects logistic regression, receiver operating characteristic curves, and the Fisher exact test. Results Thirty-four pulmonary microwave ablations were performed with the antenna a median distance of 4 mm from the heart in both perpendicular (n = 17) and parallel (n = 17) orientation. Significant arrhythmias developed during six (18%) ablations. Cardiac tissue injury occurred with 17 ablations (50%). Risk of arrhythmia and tissue injury decreased with increasing antenna distance from the heart with both antenna orientations. No cardiac complication occurred with a distance of greater than or equal to 4.4 mm from the heart. The ablation zone extended to the pleural surface adjacent to the heart in 71% of parallel and 17% of perpendicular ablations performed 5-10 mm from the heart. Conclusion Microwave lung ablations performed more than or equal to 5 mm from the heart were associated with a low risk of cardiac complications.©RSNA, 2016.
authors.affiliation: From the Departments of Radiology (G.A.C., E.N., A.M.T., F.T.L.), Cardiology (P.J.M.), and Biomedical Engineering (C.L.B.), University of Wisconsin-Madison School of Medicine and Public Health, 600 Highland Ave, Madison, WI 53792; and Research Animal Resources Center (D.J.S.) and Department of Biostatistics (S.H.), University of Wisconsin-Madison, Madison, Wis.
authors.forename: George A
authors.initials: GA
authors.lastname: Carberry
authors.affiliation: From the Departments of Radiology (G.A.C., E.N., A.M.T., F.T.L.), Cardiology (P.J.M.), and Biomedical Engineering (C.L.B.), University of Wisconsin-Madison School of Medicine and Public Health, 600 Highland Ave, Madison, WI 53792; and Research Animal Resources Center (D.J.S.) and Department of Biostatistics (S.H.), University of Wisconsin-Madison, Madison, Wis.
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Nocerino
authors.affiliation: From the Departments of Radiology (G.A.C., E.N., A.M.T., F.T.L.), Cardiology (P.J.M.), and Biomedical Engineering (C.L.B.), University of Wisconsin-Madison School of Medicine and Public Health, 600 Highland Ave, Madison, WI 53792; and Research Animal Resources Center (D.J.S.) and Department of Biostatistics (S.H.), University of Wisconsin-Madison, Madison, Wis.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Mason
authors.affiliation: From the Departments of Radiology (G.A.C., E.N., A.M.T., F.T.L.), Cardiology (P.J.M.), and Biomedical Engineering (C.L.B.), University of Wisconsin-Madison School of Medicine and Public Health, 600 Highland Ave, Madison, WI 53792; and Research Animal Resources Center (D.J.S.) and Department of Biostatistics (S.H.), University of Wisconsin-Madison, Madison, Wis.
authors.forename: Denise J
authors.initials: DJ
authors.lastname: Schwahn
authors.affiliation: From the Departments of Radiology (G.A.C., E.N., A.M.T., F.T.L.), Cardiology (P.J.M.), and Biomedical Engineering (C.L.B.), University of Wisconsin-Madison School of Medicine and Public Health, 600 Highland Ave, Madison, WI 53792; and Research Animal Resources Center (D.J.S.) and Department of Biostatistics (S.H.), University of Wisconsin-Madison, Madison, Wis.
authors.forename: Scott
authors.initials: S
authors.lastname: Hetzel
authors.affiliation: From the Departments of Radiology (G.A.C., E.N., A.M.T., F.T.L.), Cardiology (P.J.M.), and Biomedical Engineering (C.L.B.), University of Wisconsin-Madison School of Medicine and Public Health, 600 Highland Ave, Madison, WI 53792; and Research Animal Resources Center (D.J.S.) and Department of Biostatistics (S.H.), University of Wisconsin-Madison, Madison, Wis.
authors.forename: Alyssa M
authors.initials: AM
authors.lastname: Turnquist
authors.affiliation: From the Departments of Radiology (G.A.C., E.N., A.M.T., F.T.L.), Cardiology (P.J.M.), and Biomedical Engineering (C.L.B.), University of Wisconsin-Madison School of Medicine and Public Health, 600 Highland Ave, Madison, WI 53792; and Research Animal Resources Center (D.J.S.) and Department of Biostatistics (S.H.), University of Wisconsin-Madison, Madison, Wis.
authors.forename: Fred T
authors.initials: FT
authors.lastname: Lee
authors.affiliation: From the Departments of Radiology (G.A.C., E.N., A.M.T., F.T.L.), Cardiology (P.J.M.), and Biomedical Engineering (C.L.B.), University of Wisconsin-Madison School of Medicine and Public Health, 600 Highland Ave, Madison, WI 53792; and Research Animal Resources Center (D.J.S.) and Department of Biostatistics (S.H.), University of Wisconsin-Madison, Madison, Wis.
authors.forename: Christopher L
authors.initials: CL
authors.lastname: Brace
mesh_terms: D055011:Ablation Techniques / Q000009:adverse effects / Q000295:instrumentation* / Q000379:methods*; D000818:Animals; D004195:Disease Models, Animal; D005260:Female; D006321:Heart / Q000528:radiation effects*; D006331:Heart Diseases / Q000209:etiology*; D008168:Lung / Q000528:radiation effects*; D008872:Microwaves; D058958:Organs at Risk / Q000528:radiation effects*; D013552:Swine