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Radio Frequency Ablation Induced Acute Renal Failure
0022-5347/02/1681-0186/0 THE JOURNAL OF UROLOGY® Copyright © 2002 by AMERICAN UROLOGICAL ASSOCIATION, INC.®
Vol. 168, 186, July 2002 Printed in U.S.A.
Case Reports RADIO FREQUENCY ABLATION INDUCED ACUTE RENAL FAILURE KENNETH OGAN, JEFFREY A. CADEDDU*
AND
ARTHUR I. SAGALOWSKY†
From the Clinical Center for Minimally Invasive Urologic Cancer Treatment, Department of Urology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas KEY WORDS: catheter ablation, kidney neoplasms, kidney failure
Radio frequency ablation heats tissue to greater than 60C to kill tumor cells in situ. Recently, several investigators have reported their experience with radio frequency ablation for the treatment of small renal tumors. Short-term results have been encouraging, with minimal morbidity associated with this procedure. We report on a patient who suffered transient acute renal failure following multiple site radio frequency ablation combined with standard partial nephrectomy in a solitary kidney. CASE REPORT
During the evaluation of a 66-year-old man with hematuria, computerized tomography revealed bilateral multiple contrast enhancing renal tumors that were suspicious for neoplasia. There were at least 7 lesions in the right kidney, none of which was larger than 4 cm. (see figure). The left kidney contained multiple tumors as well. However several of these lesions were greater than 5 cm. Due to the size of the lesions in the left kidney, laparoscopic left radical nephrectomy was performed. Following this procedure serum creatinine plateaued at 1.8 mg./dl. (preoperative 1.3). Final pathological evaluation showed Accepted for publication February 22, 2002. * Requests for reprints: Department of Urology, The University of Texas, Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, Texas 75390-9110. † Financial interest and/or other relationship with Searle, Matritech and Schering.
multifocal renal oncocytomas ranging from 0.5 to 5 cm. in greatest diameter without evidence of malignancy. Since the patient was still at risk for malignancy in the contralateral kidney, 2 months later he underwent open exploration of the right kidney, with excision of the more exophytic tumors and radio frequency ablation of 6 endophytic lesions ranging from 1 to 3 cm. in diameter. Radio frequency ablation was performed first, with care taken to ablate visually a 5 mm. margin of normal parenchyma around each tumor. A 5-minute ablation of each tumor was performed using a temperature based system with a target temperature of 105C (RITA Medical Systems, Inc., Mountain View, California). Immediately thereafter partial nephrectomy of 3 separate lesions was performed with the renal artery and vein clamped, and the kidney packed in ice slush (cold ischemia time 56 minutes). Postoperatively nonoliguric acute renal failure developed. Creatinine peaked at 7.3 mg./dl. (normal 0.6 to 1.2). However, the patient never became fluid overloaded, hyperkalemic or acidotic and, thus, he was managed conservatively. During a 3-week period serum creatinine slowly decreased to a nadir of 2.3 mg./dl. DISCUSSION
Although radio frequency ablation of small renal tumors has become more common, there are few reported complications in the literature.1 The transient acute renal failure seen in our patient could be attributable to the cold ischemia alone. However, the amount of resected tissue and cold ischemia time were within acceptable limits. It is more likely that the temporary ischemia compounded the insult of the radio frequency ablation. Corwin et al2 demonstrated increased renal damage when radio frequency ablation was performed with simultaneous hilar occlusion, while Zager et al3 found that increased temperatures can dramatically accentuate hypoxic injury by increasing renal adenosine triphosphate losses, thereby affecting the severity of ischemic renal damage. Furthermore, it is unknown what happens to adjacent tissues that are heated but do not reach the critical temperature of 60C. Additional research needs to be focused on the safety of multiple site radio frequency ablation and on the response of the parenchyma adjacent to radio frequency ablated lesions. In the future limiting the number of radio frequency ablated lesions and/or staging the partial nephrectomy may prevent this complication. REFERENCES
Preoperative computerized tomography demonstrates multiple bilateral contrast enhancing masses. 186
1. Pavlovich, C. P., Walther, M. M., Choyke, P. L., Pautler, S. E., Chang, R., Linehan, W. M. et al: Percutaneous radio frequency ablation of small renal tumors: initial results. J Urol, 167: 10, 2002 2. Corwin, T. S., Lindberg, G., Traxer, O., Gettman, M. T., Smith, T. G., Pearle, M. S. et al: Laparoscopic radiofrequency thermal ablation of renal tissue with and without hilar occlusion. J Urol, 166: 281, 2001 3. Zager, R. A., Gmur, D. J., Bredl, C. R. and Eng, M. J.: Temperature effects on ischemic and hypoxic renal proximal tubular injury. Lab Invest, 64: 766, 1991
Vol. 168, 186, July 2002 Printed in U.S.A.
Case Reports RADIO FREQUENCY ABLATION INDUCED ACUTE RENAL FAILURE KENNETH OGAN, JEFFREY A. CADEDDU*
AND
ARTHUR I. SAGALOWSKY†
From the Clinical Center for Minimally Invasive Urologic Cancer Treatment, Department of Urology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas KEY WORDS: catheter ablation, kidney neoplasms, kidney failure
Radio frequency ablation heats tissue to greater than 60C to kill tumor cells in situ. Recently, several investigators have reported their experience with radio frequency ablation for the treatment of small renal tumors. Short-term results have been encouraging, with minimal morbidity associated with this procedure. We report on a patient who suffered transient acute renal failure following multiple site radio frequency ablation combined with standard partial nephrectomy in a solitary kidney. CASE REPORT
During the evaluation of a 66-year-old man with hematuria, computerized tomography revealed bilateral multiple contrast enhancing renal tumors that were suspicious for neoplasia. There were at least 7 lesions in the right kidney, none of which was larger than 4 cm. (see figure). The left kidney contained multiple tumors as well. However several of these lesions were greater than 5 cm. Due to the size of the lesions in the left kidney, laparoscopic left radical nephrectomy was performed. Following this procedure serum creatinine plateaued at 1.8 mg./dl. (preoperative 1.3). Final pathological evaluation showed Accepted for publication February 22, 2002. * Requests for reprints: Department of Urology, The University of Texas, Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, Texas 75390-9110. † Financial interest and/or other relationship with Searle, Matritech and Schering.
multifocal renal oncocytomas ranging from 0.5 to 5 cm. in greatest diameter without evidence of malignancy. Since the patient was still at risk for malignancy in the contralateral kidney, 2 months later he underwent open exploration of the right kidney, with excision of the more exophytic tumors and radio frequency ablation of 6 endophytic lesions ranging from 1 to 3 cm. in diameter. Radio frequency ablation was performed first, with care taken to ablate visually a 5 mm. margin of normal parenchyma around each tumor. A 5-minute ablation of each tumor was performed using a temperature based system with a target temperature of 105C (RITA Medical Systems, Inc., Mountain View, California). Immediately thereafter partial nephrectomy of 3 separate lesions was performed with the renal artery and vein clamped, and the kidney packed in ice slush (cold ischemia time 56 minutes). Postoperatively nonoliguric acute renal failure developed. Creatinine peaked at 7.3 mg./dl. (normal 0.6 to 1.2). However, the patient never became fluid overloaded, hyperkalemic or acidotic and, thus, he was managed conservatively. During a 3-week period serum creatinine slowly decreased to a nadir of 2.3 mg./dl. DISCUSSION
Although radio frequency ablation of small renal tumors has become more common, there are few reported complications in the literature.1 The transient acute renal failure seen in our patient could be attributable to the cold ischemia alone. However, the amount of resected tissue and cold ischemia time were within acceptable limits. It is more likely that the temporary ischemia compounded the insult of the radio frequency ablation. Corwin et al2 demonstrated increased renal damage when radio frequency ablation was performed with simultaneous hilar occlusion, while Zager et al3 found that increased temperatures can dramatically accentuate hypoxic injury by increasing renal adenosine triphosphate losses, thereby affecting the severity of ischemic renal damage. Furthermore, it is unknown what happens to adjacent tissues that are heated but do not reach the critical temperature of 60C. Additional research needs to be focused on the safety of multiple site radio frequency ablation and on the response of the parenchyma adjacent to radio frequency ablated lesions. In the future limiting the number of radio frequency ablated lesions and/or staging the partial nephrectomy may prevent this complication. REFERENCES
Preoperative computerized tomography demonstrates multiple bilateral contrast enhancing masses. 186
1. Pavlovich, C. P., Walther, M. M., Choyke, P. L., Pautler, S. E., Chang, R., Linehan, W. M. et al: Percutaneous radio frequency ablation of small renal tumors: initial results. J Urol, 167: 10, 2002 2. Corwin, T. S., Lindberg, G., Traxer, O., Gettman, M. T., Smith, T. G., Pearle, M. S. et al: Laparoscopic radiofrequency thermal ablation of renal tissue with and without hilar occlusion. J Urol, 166: 281, 2001 3. Zager, R. A., Gmur, D. J., Bredl, C. R. and Eng, M. J.: Temperature effects on ischemic and hypoxic renal proximal tubular injury. Lab Invest, 64: 766, 1991