Percutaneous radiofrequency ablation of renal parenchyma: experimental study on the optimal temperature and the impact of vasoactive drugs.
OBJECTIVE
Radiofrequency (RF) is an efficient, inexpensive, safe, and friendly option for the management of small renal tumors. The objective was to evaluate the ideal temperature for renal cell destruction in dogs by RF and to verify whether the injection of vasoactive drugs, such as prostaglandin E1 and adrenaline, can help to improve the results, compared with "dry" RF ablation.


METHODS
The study was divided into three phases: Initially, 16 dogs of comparable weight underwent RF ablation of the renal parenchyma at temperatures of 80°C, 90°C, and 100°C. After that, seven other dogs received adrenaline (vasoconstrictor) and seven received prostaglandin E1 (vasodilator). Finally, the results from 14 animals were compared with those of the 16 (dry RF) dogs at the optimum temperature found. After 14 days, the animals underwent nephrectomy to evaluate the size of the lesions (width and depth), histology examination, and were then sacrificed.


RESULTS
There were no clinical or surgical complications in any of the dogs, and none died before the 14th day after the procedure. The optimum temperature was found to be 90°C. Prostaglandin E1 resulted in significantly larger lesions (in depth and width) than adrenaline, with lower impedance. Prostaglandin did not increase the lesions compared with dry RF. All the kidneys presented total coagulation necrosis, with no viable cells in the histologic analysis of the treated tissue.


CONCLUSIONS
In the ablation of renal cells by RF, prostaglandin produced larger lesions (in depth and width) than the same procedure using adrenaline, and its performance was similar to that of RF without injection of drugs.
Learning and Research Surgery Center Vicky Safra (CEPEC), Urology Department of Universidade de São Paulo Medical School (FMUSP), São Paulo, Brazil. mvbqueiroz@globo.com
Marcus Vinicius Baptista
MV
Queiroz
Ricardo Jordão
RJ
Duarte
Chen Jen
CJ
Shan
Luiz
L
Saldanha
Anuar
A
Mitre
Miguel
M
Srougi
D000527:Alprostadil / Q000008:administration & dosage / Q000494:pharmacology; D000818:Animals; D017115:Catheter Ablation / Q000379:methods*; D004285:Dogs; D017097:Electric Impedance; D004837:Epinephrine / Q000008:administration & dosage / Q000494:pharmacology; D007668:Kidney / Q000187:drug effects* / Q000473:pathology / Q000601:surgery*; D013696:Temperature; D014662:Vasoconstrictor Agents / Q000494:pharmacology*
D014662:Vasoconstrictor Agents; D000527:Alprostadil; D004837:Epinephrine