Radiofrequency ablation with and without balloon occlusion of the renal artery: an experimental study in porcine kidneys.
OBJECTIVE
To compare thermal lesion volumes and associated renal damage (other than thermal lesions) when radiofrequency (RF) ablation is performed with and without balloon occlusion of the renal artery in normal porcine kidneys.


METHODS
RF ablation was performed in six pigs. An electrode with eight circumferential prongs arranged in a circle 20 mm in diameter was inserted into the lower pole of the kidney. In each animal, renal ablation was performed with balloon occlusion of the renal artery in one kidney and without balloon occlusion in the contralateral kidney. The volume of the thermal lesion and associated renal damage other than the thermal lesion were compared by angiography and histology between the groups of kidneys ablated with and without arterial occlusion. The volume of thermal lesion was measured by tracing the thermal lesions of sliced kidneys and multiplying each area by the slice thickness (5 mm).


RESULTS
Renal ablation with arterial occlusion consistently created nearly spherical thermal lesions with a mean volume of 5,399 mm(3) +/- 902. RF ablation without arterial occlusion, conversely, created irregular, mushroom-shaped thermal lesions limited to the region around the prongs and shaft of the electrode, with a mean volume of 2,759 mm(3) +/- 1,069 (P <.001). Renal arteriography showed occlusion of interlobar arteries penetrating the thermal lesions and perfusion defects peripheral to the thermal lesions immediately after RF ablation. Perfusion defects were larger in kidneys ablated with arterial occlusion than in those ablated without arterial occlusion (1,499 cm(2) +/- 354 vs 499 cm(2) +/- 352; P <.001).


CONCLUSIONS
Renal RF ablation with arterial occlusion consistently provides larger thermal lesions than ablation without arterial occlusion does, but it induces renal infarction peripheral to the thermal lesion.
Kariya
Zentaro
Z
Department of Radiology, Mie University School of Medicine, 2-174 Edobashi, Tsu, Mie 514.
Yamakado
Koichiro
K
Nakatuka
Atsuhiro
A
Onoda
Mitsutoshi
M
Kobayasi
Shigeki
S
Takeda
Kan
K
D000792:Angiography; D000818:Animals; D021721:Balloon Occlusion; D017115:Catheter Ablation; D005260:Female; D012077:Renal Artery / Q000000981:diagnostic imaging; D013552:Swine