- Email: [email protected]
Role of Laparoscopic Nephrectomy for Management of Symptomatic Nephrogenic Hypertension
Adult Urology Role of Laparoscopic Nephrectomy for Management of Symptomatic Nephrogenic Hypertension Abbas Basiri, Naser Simforoosh, Hamid Reza Abdi, Seyed Saeed Shahrokhi, and Seyed Mohammadmehdi Hosseini-Moghaddam OBJECTIVES
METHODS
RESULTS
CONCLUSIONS
To investigate the efficacy of laparoscopic nephrectomy for the management of hypertension associated with a unilateral poorly functioning kidney in adults and the role of some variables in the prediction of its outcome in the management of nephrogenic hypertension. We conducted this study on 22 hypertensive patients with a unilateral, minimally functioning kidney. We included patients with a well-functioned contralateral kidney, no renal tumors, no renovascular hypertension, and no diagnosis of end-stage renal disease. All patients had poorly controlled hypertension or preferred to discontinue medical therapy. Their age at the onset of hypertension, gender, age at laparoscopic nephrectomy, and the interval from diagnosis to intervention were evaluated. A complete response was defined as blood pressure normalization without medical treatment. A partial response was defined as a decrease in the medication requirements and/or a 10-mm Hg decrease in diastolic blood pressure after surgery. Measurement of plasma renin activity was not available in our country at the time of the study. After nephrectomy, 12 (54.5%), 2 (9.1%), and 8 (36.4%) patients had a complete, partial, or no response to the surgery, respectively. No significant association was found between the response to laparoscopic nephrectomy and age, gender, and mean blood pressure. Only the hypertensionrelated signs and symptoms before surgery were significantly associated with the response to laparoscopic nephrectomy (P ⫽ 0.01) on both univariate and multivariate analysis. Nephrectomy seems effective for the management of nephrogenic hypertension in patients who wish to discontinue medical therapy. We suggest paying attention to the preoperative hypertension-related symptoms for the prediction of the response to nephrectomy. UROLOGY 70: 427– 430, 2007. © 2007 Elsevier Inc.
N
ephrogenic hypertension seems to be a common cause of secondary hypertension. The new pharmacologic agents have decreased the role of nephrectomy in the management of hypertension. However, this procedure remains an option for the treatment of nephrogenic hypertension, specifically, in patients who are not candidates for endarterectomy, angioplasty, or reconstructive surgery.1,2 In patients with a minimally functioning abnormal kidney, the success of laparoscopic nephrectomy for the treatment of nephrogenic hypertension has not been appropriately studied.2 The main aim of the present study was to explore the success rate of laparoscopic nephrectomy for the management of nephrogenic hypertension in cases with a uni-
From the Urology and Nephrology Research Center, Labbafinejad Medical Center, Shaheed Beheshti Medical University, Tehran, Iran and Department of Infectious Diseases and Tropical Medicine, Shaheed Beheshti Medical University,Tehran, Iran Reprint requests: Abbas Basiri, M.D., Urology and Nephrology Research Center, Boostan 9th, Pasdaran Avenue, Tehran, I.R. 16666-79951, Iran. E-mail: h_sasan@ hotmail.com Submitted: November 26, 2006; accepted (with revisions): April 18, 2007
© 2007 Elsevier Inc. All Rights Reserved
lateral poorly functioning kidney and the effect of the variables that might play predictive roles in estimating the response to nephrectomy.
MATERIAL AND METHODS Our study was performed at Shaheed Labbafinejad Medical Center from March 2000 to March 2006. In this period, 22 hypertensive patients (greater than the 95th percentile for age and height) with a unilateral poorly functioning kidney were included. Our protocol comprised Doppler ultrasonography for all subjects and, in the case of any positive finding in favor of renovascular hypertension, captopril scans. In our study, a peak systolic velocity greater than 180 cm/s in the renal artery was indicative of renal artery stenosis on Doppler ultrasonography. All patients had a poorly functioning kidney and poorly controlled hypertension or insisted on discontinuing antihypertensive drugs; hence, we performed laparoscopic nephrectomy for the management of hypertension. Of the 22 patients, 14 sought treatment of hypertension-related symptoms and 8 presented to our medical center for nephrectomy because of recurrent urinary tract infection, ipsilateral intractable flank pain, or 0090-4295/07/$32.00 doi:10.1016/j.urology.2007.04.020
427
Table 1. Difference between responders and nonresponders to nephrectomy Variable Age (y) Mean Range Gender Male Female Signs and symptoms of hypertension (n) Preoperative systolic blood pressure (mm Hg) Mean Range Interval between diagnosis of hypertension and nephrectomy (y) Mean Range Follow-up (mo) Mean Range
Responders (n ⫽ 14)
Nonresponders (n ⫽ 8)
39.9 12–69
49.1 16–81
0.2*
4 10 12
5 3 2
0.1†
185.7 150–250
170 150–200
0.3*
P Value
0.008†
10 1–20
8.7 1–15
0.7*
20.3 1–54
22.8 12–33
0.6*
* Mann-Whitney u test. † Fisher’s exact test.
urinary stones. Our inclusion criteria were a well-functioning contralateral kidney, no renal tumors, and no renovascular hypertension. The Urology and Nephrology Research Center in Tehran, Iran, has adopted codes of ethics to guide human experimentation. The preoperative evaluation included history taking and physical examination, routine blood tests (blood urea nitrogen, creatinine, Na⫹, K⫹, complete blood count, erythrocyte sedimentation rate), ultrasonography, Doppler ultrasonography, and diethylenetriamine pentaacetic acid isotope scanning. No patient had a renovascular disorder on Doppler ultrasonography, and angiography was performed as needed. We considered poorly functioning kidneys as kidneys with less than 10% function on diethylenetriamine pentaacetic acid scan. During the study period, measurement of plasma renin activity was not available in our country. The patient was placed in the modified flank position and general anesthesia instituted. Using the transperitoneal approach, the video laparoscope was introduced through a 10-mm umbilical port. We used a 10-mm pararectal and 5-mm epigastric port for the dissecting instruments. After mobilization of the colon, dissection of the kidney, and clipping and cutting of the renal vessels, we removed the kidney by way of the umbilical port that had been slightly widened. In this study, age, gender, systolic and diastolic blood pressure, interval between the diagnosis of hypertension to laparoscopic nephrectomy, and hypertension-related symptoms were considered as variables. The latter included headache, palpitation, flushing, dizziness, chest tightness, blurred vision, dyspnea, nasal bleeding, hematuria, and end organ complications. The evaluation of the response to nephrectomy was defined as cured (a complete response) when the patient had a blood pressure measurement of 140/90 mm Hg or less using no medical treatment for hypertension; improved (partial response) when diastolic blood pressure had decreased by at least 10 mm Hg postoperatively or if less medical treatment was needed for blood pressure control compared with preoperatively2; and no response when none of criteria for a complete or partial response were met. 428
Patients were followed up postoperatively with blood pressure measurements four times daily during their hospital admission, daily between discharge and 2 weeks later, weekly for up to 2 months, and monthly thereafter. Statistical analyses were performed using the chi-square test, Mann-Whitney U test, logistic regression analysis, and Fisher’s exact test. We considered P ⬍0.05 as significant.
RESULTS No patient had findings suspicious for renovascular hypertension on ultrasonography; therefore, we did not perform renal angiography. The ultrasound studies demonstrated shrunken kidneys with a mean size of 7 ⫾ 1.5 cm. For all patients, the isotope scan showed the function of the involved kidney to be less than 10%. The mean operative time was 70 ⫾ 10 minutes. No patient experienced major intraoperative or postoperative complications. The mean kidney size was 7 ⫾ 1.5 cm on ultrasonography. The mean preoperative serum creatinine was 1.3 ⫾ 0.5 mg/dL. The mean preoperative and postoperative systolic blood pressure was 181.8 ⫾ 35.4 mm Hg and 130.5 ⫾ 20 mm Hg, respectively (P ⫽ 0.001). The mean preoperative and postoperative diastolic blood pressure was 98.1 ⫾ 10.3 mm Hg and 81.8 ⫾ 6 mm Hg, respectively (P ⫽ 0.01). After nephrectomy, 12 (54.5%), 2 (9.1%), and 8 (36.4%) patients had a complete, partial, or no response, respectively. The mean follow-up time was 22 months (range 2 to 54). Table 1 demonstrates the differences between those with (partial or complete response) and without a response. On univariate analysis, we found no significant association between the response to nephrectomy and age, gender, mean preoperative blood pressure, or interval from diagnosis of hypertension to nephrectomy. Only the hypertension-related signs and symptoms before surgery were significantly associated with the response to nephrectomy using Fisher’s exact UROLOGY 70 (3), 2007
test (P ⫽ 0.01). This significant finding was confirmed using multivariate logistic regression analysis (P ⫽ 0.005). Statistical analysis comparing patients with a complete response to nephrectomy (n ⫽ 12) and those with no response also demonstrated a significant difference for hypertension-related signs and symptoms (P ⫽ 0.02) on both univariate and multivariate analysis.
COMMENT Although much attention has been given to renovascular disease involving the main renal arteries, renin-producing kidney diseases seem more important.1,2 The association between hypertension and chronic renal diseases is well known,3 and kidney disorders are by far the most common cause of secondary hypertension.4 The pathophysiology of renal hypertension can be renin or volume dependent. Renin-mediated hypertension can be secondary to a variety of renal parenchymal diseases. The mechanism of renin-mediated hypertension in kidneys with segmental scarring is ischemia of relatively normal renal cortex in proximity to areas of interstitial fibrosis within which are small vessels with intimal thickening.5 For confirmation of renovascular hypertension, one can use captopril scanning, which has a sensitivity of 90% to 93% and specificity of 93% to 96%; the renal renin ratio, with a sensitivity of 92% and specificity of 42%; and/or Doppler ultrasonography, with a sensitivity of 98% and specificity of 98%.6 –10 Consequently, we performed Doppler ultrasonography to rule out renovascular hypertension and excluded patients with positive findings. We noted no indication for Doppler ultrasonography and captopril renal scan for confirmation of nephrogenic hypertension; although measurement of the renal renin ratio might be helpful. However, this test is not available everywhere and not reliable in all conditions; in addition, it can be equivocal or inconsistent.11 Nephrectomy was reported as a successful surgical option in normalizing blood pressure in children with benign renal hypertension and a normal contralateral kidney.1 Baez-Trinidad et al.6 showed, in pediatric patients with refractory hypertension with a unilateral abnormal kidney that had minimal function on nuclear imaging, that renin studies do not alter the decision process and might be misleading. Therefore, one could decide not to routinely obtain plasma or renin levels in this setting. In children, researchers have cited that if hypertension is persistent and the contralateral kidney is normal, nephrectomy is therapeutic, regardless of the renal vein renin levels.7 In hypertensive pediatric patients with a minimally functioning abnormal kidney, using angiography and selected renal vein determination might be unnecessary.6 Johal et al.1 have conducted a retrospective review on outpatient records of 118 hypertensive children who underwent nephrectomy from 1968 to 2003. The patients included in their study were those who had undergone unilateral nephrectomy for renal hypertension because of UROLOGY 70 (3), 2007
a benign renal lesion with a normal contralateral kidney. In all, 21 had complete records and the follow-up data were reviewed. They raised the question regarding the necessity for selective renin determination in patients with hypertension and a poorly functioning kidney.1 Although their investigation was similar to our experiment, studying hypertensive children in their study was the only discrepancy. A review of all case series revealed that nephrectomy has a success rate of 88% to 100%1,6 in pediatric nephrogenic hypertension; however, no study to our knowledge has determined the predictive factors for the estimation of success. No previous report, to our knowledge, has demonstrated the success rate of nephrectomy in hypertensive adult patients with a unilateral poorly functioning kidney and the predictive role of symptoms in the estimation of the success of this procedure in any age group. Because our study uncovered the significant role of clinical presentation in this regard, we suggest additional studies to extend our understanding. In some previous reports, it was emphasized that specific symptoms of hypertension might be related to some etiologies8 and that some symptoms might arise in a long-term manner.9,10 If we accept these two hypotheses, additional studies might be helpful to determine which signs or symptoms, among the clinical manifestations of hypertension, are useful for the prediction of the outcome of nephrectomy; and, if we believe that some clinical presentations are much more associated with some causes of hypertension, can we explore any association that might exist between specific etiologies of nephrogenic hypertension and the success of nephrectomy?
CONCLUSIONS Nephrectomy, especially in the laparoscopic era with less morbidity compared with open surgery, seems safe and effective for the management of nephrogenic hypertension in patients who wish to discontinue medical therapy. Because urologists usually rely on some laboratory variables, such as the renin/vein ratio, to predict the outcome of nephrectomy that might be misleading, we strongly recommend additional investigation into the importance of signs and symptoms in this regard. References 1. Johal NS, Kraklau D, and Cuckow PM: The role of unilateral nephrectomy in the treatment of nephrogenic hypertension in children. BJU Int 95: 140 –142, 2005. 2. Troitskii OA, and Romanov VA: Laparoscopic nephrectomy in a patient with a parenchymatous form of nephrogenic hypertension. Urol Nefrol 2: 8 –11, 1996. 3. Campese VM, Mitra N, and Sandee D: Hypertension in renal parenchymal disease: why is it so resistant to treatment? Kidney Int 69: 967–973, 2006. 4. Preston RA, and Epstein M: Renal parenchymal disease and hypertension. Semin Nephrol 15: 138 –151, 1995 . 5. Novik AC, and Fergany A: Renovascular hypertension and ischemic nephropathy, in Walsh PC, Retik AB, Vaughan ED Jr, et al.
429
(Eds): Campbell’s Urology, 8th ed. Philadelphia, WB Saunders, 2002, vol 1, pp 229 –266. 6. Baez-Trinidad LG, Lendvay TS, Broecker BH, et al: Efficacy of nephrectomy for the treatment of nephrogenic hypertension in a pediatric population. J Urol 170: 1655–1657, 2003. 7. Taylor RG, Azmy AF, and Young DG: Long-term follow-up of surgical renal hypertension. J Pediatr Surg 22: 228 –230, 1987. 8. Graham JR, Bana D, and Yap A: Headache, hypertension and renal disease. Res Clin Stud Headache 6: 147–154, 1978.
430
9. Neumann J, Ligtenberg G, Klein II, et al: Sympathetic hyperactivity in chronic kidney disease: pathogenesis, clinical relevance, and treatment. Kidney Int 65: 1568 –1576, 2004. 10. Morse SA, Dang A, Thakur V, et al: Hypertension in chronic dialysis patients: pathophysiology, monitoring, and treatment. Am J Med Sci 325: 194 –201, 2003. 11. Fletcher EC, Bao G, and Li R: Renin activity and blood pressure in response to chronic episodic hypoxia. Hypertension 34: 309 –314, 1999.
UROLOGY 70 (3), 2007
METHODS
RESULTS
CONCLUSIONS
To investigate the efficacy of laparoscopic nephrectomy for the management of hypertension associated with a unilateral poorly functioning kidney in adults and the role of some variables in the prediction of its outcome in the management of nephrogenic hypertension. We conducted this study on 22 hypertensive patients with a unilateral, minimally functioning kidney. We included patients with a well-functioned contralateral kidney, no renal tumors, no renovascular hypertension, and no diagnosis of end-stage renal disease. All patients had poorly controlled hypertension or preferred to discontinue medical therapy. Their age at the onset of hypertension, gender, age at laparoscopic nephrectomy, and the interval from diagnosis to intervention were evaluated. A complete response was defined as blood pressure normalization without medical treatment. A partial response was defined as a decrease in the medication requirements and/or a 10-mm Hg decrease in diastolic blood pressure after surgery. Measurement of plasma renin activity was not available in our country at the time of the study. After nephrectomy, 12 (54.5%), 2 (9.1%), and 8 (36.4%) patients had a complete, partial, or no response to the surgery, respectively. No significant association was found between the response to laparoscopic nephrectomy and age, gender, and mean blood pressure. Only the hypertensionrelated signs and symptoms before surgery were significantly associated with the response to laparoscopic nephrectomy (P ⫽ 0.01) on both univariate and multivariate analysis. Nephrectomy seems effective for the management of nephrogenic hypertension in patients who wish to discontinue medical therapy. We suggest paying attention to the preoperative hypertension-related symptoms for the prediction of the response to nephrectomy. UROLOGY 70: 427– 430, 2007. © 2007 Elsevier Inc.
N
ephrogenic hypertension seems to be a common cause of secondary hypertension. The new pharmacologic agents have decreased the role of nephrectomy in the management of hypertension. However, this procedure remains an option for the treatment of nephrogenic hypertension, specifically, in patients who are not candidates for endarterectomy, angioplasty, or reconstructive surgery.1,2 In patients with a minimally functioning abnormal kidney, the success of laparoscopic nephrectomy for the treatment of nephrogenic hypertension has not been appropriately studied.2 The main aim of the present study was to explore the success rate of laparoscopic nephrectomy for the management of nephrogenic hypertension in cases with a uni-
From the Urology and Nephrology Research Center, Labbafinejad Medical Center, Shaheed Beheshti Medical University, Tehran, Iran and Department of Infectious Diseases and Tropical Medicine, Shaheed Beheshti Medical University,Tehran, Iran Reprint requests: Abbas Basiri, M.D., Urology and Nephrology Research Center, Boostan 9th, Pasdaran Avenue, Tehran, I.R. 16666-79951, Iran. E-mail: h_sasan@ hotmail.com Submitted: November 26, 2006; accepted (with revisions): April 18, 2007
© 2007 Elsevier Inc. All Rights Reserved
lateral poorly functioning kidney and the effect of the variables that might play predictive roles in estimating the response to nephrectomy.
MATERIAL AND METHODS Our study was performed at Shaheed Labbafinejad Medical Center from March 2000 to March 2006. In this period, 22 hypertensive patients (greater than the 95th percentile for age and height) with a unilateral poorly functioning kidney were included. Our protocol comprised Doppler ultrasonography for all subjects and, in the case of any positive finding in favor of renovascular hypertension, captopril scans. In our study, a peak systolic velocity greater than 180 cm/s in the renal artery was indicative of renal artery stenosis on Doppler ultrasonography. All patients had a poorly functioning kidney and poorly controlled hypertension or insisted on discontinuing antihypertensive drugs; hence, we performed laparoscopic nephrectomy for the management of hypertension. Of the 22 patients, 14 sought treatment of hypertension-related symptoms and 8 presented to our medical center for nephrectomy because of recurrent urinary tract infection, ipsilateral intractable flank pain, or 0090-4295/07/$32.00 doi:10.1016/j.urology.2007.04.020
427
Table 1. Difference between responders and nonresponders to nephrectomy Variable Age (y) Mean Range Gender Male Female Signs and symptoms of hypertension (n) Preoperative systolic blood pressure (mm Hg) Mean Range Interval between diagnosis of hypertension and nephrectomy (y) Mean Range Follow-up (mo) Mean Range
Responders (n ⫽ 14)
Nonresponders (n ⫽ 8)
39.9 12–69
49.1 16–81
0.2*
4 10 12
5 3 2
0.1†
185.7 150–250
170 150–200
0.3*
P Value
0.008†
10 1–20
8.7 1–15
0.7*
20.3 1–54
22.8 12–33
0.6*
* Mann-Whitney u test. † Fisher’s exact test.
urinary stones. Our inclusion criteria were a well-functioning contralateral kidney, no renal tumors, and no renovascular hypertension. The Urology and Nephrology Research Center in Tehran, Iran, has adopted codes of ethics to guide human experimentation. The preoperative evaluation included history taking and physical examination, routine blood tests (blood urea nitrogen, creatinine, Na⫹, K⫹, complete blood count, erythrocyte sedimentation rate), ultrasonography, Doppler ultrasonography, and diethylenetriamine pentaacetic acid isotope scanning. No patient had a renovascular disorder on Doppler ultrasonography, and angiography was performed as needed. We considered poorly functioning kidneys as kidneys with less than 10% function on diethylenetriamine pentaacetic acid scan. During the study period, measurement of plasma renin activity was not available in our country. The patient was placed in the modified flank position and general anesthesia instituted. Using the transperitoneal approach, the video laparoscope was introduced through a 10-mm umbilical port. We used a 10-mm pararectal and 5-mm epigastric port for the dissecting instruments. After mobilization of the colon, dissection of the kidney, and clipping and cutting of the renal vessels, we removed the kidney by way of the umbilical port that had been slightly widened. In this study, age, gender, systolic and diastolic blood pressure, interval between the diagnosis of hypertension to laparoscopic nephrectomy, and hypertension-related symptoms were considered as variables. The latter included headache, palpitation, flushing, dizziness, chest tightness, blurred vision, dyspnea, nasal bleeding, hematuria, and end organ complications. The evaluation of the response to nephrectomy was defined as cured (a complete response) when the patient had a blood pressure measurement of 140/90 mm Hg or less using no medical treatment for hypertension; improved (partial response) when diastolic blood pressure had decreased by at least 10 mm Hg postoperatively or if less medical treatment was needed for blood pressure control compared with preoperatively2; and no response when none of criteria for a complete or partial response were met. 428
Patients were followed up postoperatively with blood pressure measurements four times daily during their hospital admission, daily between discharge and 2 weeks later, weekly for up to 2 months, and monthly thereafter. Statistical analyses were performed using the chi-square test, Mann-Whitney U test, logistic regression analysis, and Fisher’s exact test. We considered P ⬍0.05 as significant.
RESULTS No patient had findings suspicious for renovascular hypertension on ultrasonography; therefore, we did not perform renal angiography. The ultrasound studies demonstrated shrunken kidneys with a mean size of 7 ⫾ 1.5 cm. For all patients, the isotope scan showed the function of the involved kidney to be less than 10%. The mean operative time was 70 ⫾ 10 minutes. No patient experienced major intraoperative or postoperative complications. The mean kidney size was 7 ⫾ 1.5 cm on ultrasonography. The mean preoperative serum creatinine was 1.3 ⫾ 0.5 mg/dL. The mean preoperative and postoperative systolic blood pressure was 181.8 ⫾ 35.4 mm Hg and 130.5 ⫾ 20 mm Hg, respectively (P ⫽ 0.001). The mean preoperative and postoperative diastolic blood pressure was 98.1 ⫾ 10.3 mm Hg and 81.8 ⫾ 6 mm Hg, respectively (P ⫽ 0.01). After nephrectomy, 12 (54.5%), 2 (9.1%), and 8 (36.4%) patients had a complete, partial, or no response, respectively. The mean follow-up time was 22 months (range 2 to 54). Table 1 demonstrates the differences between those with (partial or complete response) and without a response. On univariate analysis, we found no significant association between the response to nephrectomy and age, gender, mean preoperative blood pressure, or interval from diagnosis of hypertension to nephrectomy. Only the hypertension-related signs and symptoms before surgery were significantly associated with the response to nephrectomy using Fisher’s exact UROLOGY 70 (3), 2007
test (P ⫽ 0.01). This significant finding was confirmed using multivariate logistic regression analysis (P ⫽ 0.005). Statistical analysis comparing patients with a complete response to nephrectomy (n ⫽ 12) and those with no response also demonstrated a significant difference for hypertension-related signs and symptoms (P ⫽ 0.02) on both univariate and multivariate analysis.
COMMENT Although much attention has been given to renovascular disease involving the main renal arteries, renin-producing kidney diseases seem more important.1,2 The association between hypertension and chronic renal diseases is well known,3 and kidney disorders are by far the most common cause of secondary hypertension.4 The pathophysiology of renal hypertension can be renin or volume dependent. Renin-mediated hypertension can be secondary to a variety of renal parenchymal diseases. The mechanism of renin-mediated hypertension in kidneys with segmental scarring is ischemia of relatively normal renal cortex in proximity to areas of interstitial fibrosis within which are small vessels with intimal thickening.5 For confirmation of renovascular hypertension, one can use captopril scanning, which has a sensitivity of 90% to 93% and specificity of 93% to 96%; the renal renin ratio, with a sensitivity of 92% and specificity of 42%; and/or Doppler ultrasonography, with a sensitivity of 98% and specificity of 98%.6 –10 Consequently, we performed Doppler ultrasonography to rule out renovascular hypertension and excluded patients with positive findings. We noted no indication for Doppler ultrasonography and captopril renal scan for confirmation of nephrogenic hypertension; although measurement of the renal renin ratio might be helpful. However, this test is not available everywhere and not reliable in all conditions; in addition, it can be equivocal or inconsistent.11 Nephrectomy was reported as a successful surgical option in normalizing blood pressure in children with benign renal hypertension and a normal contralateral kidney.1 Baez-Trinidad et al.6 showed, in pediatric patients with refractory hypertension with a unilateral abnormal kidney that had minimal function on nuclear imaging, that renin studies do not alter the decision process and might be misleading. Therefore, one could decide not to routinely obtain plasma or renin levels in this setting. In children, researchers have cited that if hypertension is persistent and the contralateral kidney is normal, nephrectomy is therapeutic, regardless of the renal vein renin levels.7 In hypertensive pediatric patients with a minimally functioning abnormal kidney, using angiography and selected renal vein determination might be unnecessary.6 Johal et al.1 have conducted a retrospective review on outpatient records of 118 hypertensive children who underwent nephrectomy from 1968 to 2003. The patients included in their study were those who had undergone unilateral nephrectomy for renal hypertension because of UROLOGY 70 (3), 2007
a benign renal lesion with a normal contralateral kidney. In all, 21 had complete records and the follow-up data were reviewed. They raised the question regarding the necessity for selective renin determination in patients with hypertension and a poorly functioning kidney.1 Although their investigation was similar to our experiment, studying hypertensive children in their study was the only discrepancy. A review of all case series revealed that nephrectomy has a success rate of 88% to 100%1,6 in pediatric nephrogenic hypertension; however, no study to our knowledge has determined the predictive factors for the estimation of success. No previous report, to our knowledge, has demonstrated the success rate of nephrectomy in hypertensive adult patients with a unilateral poorly functioning kidney and the predictive role of symptoms in the estimation of the success of this procedure in any age group. Because our study uncovered the significant role of clinical presentation in this regard, we suggest additional studies to extend our understanding. In some previous reports, it was emphasized that specific symptoms of hypertension might be related to some etiologies8 and that some symptoms might arise in a long-term manner.9,10 If we accept these two hypotheses, additional studies might be helpful to determine which signs or symptoms, among the clinical manifestations of hypertension, are useful for the prediction of the outcome of nephrectomy; and, if we believe that some clinical presentations are much more associated with some causes of hypertension, can we explore any association that might exist between specific etiologies of nephrogenic hypertension and the success of nephrectomy?
CONCLUSIONS Nephrectomy, especially in the laparoscopic era with less morbidity compared with open surgery, seems safe and effective for the management of nephrogenic hypertension in patients who wish to discontinue medical therapy. Because urologists usually rely on some laboratory variables, such as the renin/vein ratio, to predict the outcome of nephrectomy that might be misleading, we strongly recommend additional investigation into the importance of signs and symptoms in this regard. References 1. Johal NS, Kraklau D, and Cuckow PM: The role of unilateral nephrectomy in the treatment of nephrogenic hypertension in children. BJU Int 95: 140 –142, 2005. 2. Troitskii OA, and Romanov VA: Laparoscopic nephrectomy in a patient with a parenchymatous form of nephrogenic hypertension. Urol Nefrol 2: 8 –11, 1996. 3. Campese VM, Mitra N, and Sandee D: Hypertension in renal parenchymal disease: why is it so resistant to treatment? Kidney Int 69: 967–973, 2006. 4. Preston RA, and Epstein M: Renal parenchymal disease and hypertension. Semin Nephrol 15: 138 –151, 1995 . 5. Novik AC, and Fergany A: Renovascular hypertension and ischemic nephropathy, in Walsh PC, Retik AB, Vaughan ED Jr, et al.
429
(Eds): Campbell’s Urology, 8th ed. Philadelphia, WB Saunders, 2002, vol 1, pp 229 –266. 6. Baez-Trinidad LG, Lendvay TS, Broecker BH, et al: Efficacy of nephrectomy for the treatment of nephrogenic hypertension in a pediatric population. J Urol 170: 1655–1657, 2003. 7. Taylor RG, Azmy AF, and Young DG: Long-term follow-up of surgical renal hypertension. J Pediatr Surg 22: 228 –230, 1987. 8. Graham JR, Bana D, and Yap A: Headache, hypertension and renal disease. Res Clin Stud Headache 6: 147–154, 1978.
430
9. Neumann J, Ligtenberg G, Klein II, et al: Sympathetic hyperactivity in chronic kidney disease: pathogenesis, clinical relevance, and treatment. Kidney Int 65: 1568 –1576, 2004. 10. Morse SA, Dang A, Thakur V, et al: Hypertension in chronic dialysis patients: pathophysiology, monitoring, and treatment. Am J Med Sci 325: 194 –201, 2003. 11. Fletcher EC, Bao G, and Li R: Renin activity and blood pressure in response to chronic episodic hypoxia. Hypertension 34: 309 –314, 1999.
UROLOGY 70 (3), 2007