CplriAstdrninpift

tlispmae

A

Acute Renal Failure After Continuous Flow Irrigation in Patients TreatedWith Potassium-Titanyl-Phosphate Laser Vaporization of Prostate

Min Jeong Kim, MD,1 Alexander Bachmann, MD,2 Michael J. Mihatsch, MD,3 Robin Ruszat, MD,2

Tulio Sulser, MD,2 and Michael Mayr, MD1

Cases of acute renal failure after transurethral resection of the prostate have been reported since thelate 1940s. The pathogenic mechanisms postulated were acute hemolysis, renal interstitial edema,ischemic tubular injury, and rhabdomyolysis, resulting from the absorption of irrigating fluid. Because ofthe excellent hemostasis of the new laser techniques, absorption of irrigation fluid is supposed to beminimal. Potassium-titanyl-phosphate laser vaporization is regarded as the most recent advance in thetreatment of patients with benign prostate hyperplasia, with excellent hemostatic properties. We report 3cases of acute renal failure after continuous flow irrigation in patients treated with potassium-titanyl-phosphate laser vaporization. Renal failure occurred on postoperative day 1, all patients becameoligoanuric, 2 patients required hemodialysis therapy, and incomplete recovery of renal function wasseen within 1 month. Biopsy findings were similar in all patients, consisting of widening of tubularlumens; partly containing Tamm-Horsfall protein casts, but neither hemoglobin nor myoglobin casts;flattened tubular epithelial cells with loss of brush borders; and variably edematous interstitium. Duringlaser vaporization, irrigation pressure usually is higher than the physiological intravesical pressure andranges from 60 to 100 mm Hg. High intravesical pressure may facilitate not only irrigating fluidabsorption, but also transient urinary stasis or even vesicoureteral reflux. The latter may directlydamage tubular epithelial cells and cause acute renal failure. Thus, intravesical pressure should be keptas low as possible, even during laser prostatectomy.Am J Kidney Dis 51:e19-e24. © 2008 by the National Kidney Foundation, Inc.

INDEX WORDS: Acute renal failure; green light (potassium-titanyl-phosphate [KTP]) laser vaporizationof prostate; photoselective vaporization.

pgAt

P

tLbwwcr

Nc

N1

fsm

ases of acute renal failure (ARF) as a com-plication of transurethral resection of the

rostate (TURP) have been reported since theate 1940s. Initially, acute hemolysis syndromeesulting from systemic absorption of hypotonicrrigating solution was regarded as the cause ofRF.1,2 Despite the transition to isotonic or

lightly hypotonic irrigation solutions, absorp-ion of as much as several liters of irrigating fluiduring TURP frequently resulted in transurethralesection syndrome, including circulatory andeurological symptoms and ARF.3 Absorption ofrrigating fluid occurs most frequently when ve-ous sinuses are injured or prostate capsules areerforated.4 The high intravesical pressure dur-ng the irrigation favors fluid absorption.5 There-ore, continuous low pressure irrigation becamehe standard procedure.

The new technique of transurethral photoselec-ive vaporization of prostate with green light-aser (potassium-titanyl-phosphate [KTP] laser)s promising. Because of the effective hemosta-is, almost bloodless removal of prostate tissue isossible and absorption of irrigating fluid isinimized.6,7 Even patients with ongoing oral

nticoagulation were treated successfully.8 How-

ver, after this new procedure, we observed 3

merican Journal of Kidney Diseases, Vol 51, No 4 (April), 2008: p

atients with ARF, one of whom was a kidneyraft recipient. To our knowledge, no report ofRF in patients treated with KTP laser vaporiza-

ion was made to date.

CASE REPORTS

atient 1A 76-year-old man with long-term decreased kidney func-

ion (serum creatinine, 1.2 to 1.3 mg/dL [106 to 119 �mol/]) was admitted for KTP laser vaporization of the prostateecause of obstructive prostate hyperplasia. Prostate volumeas 120 mL. Preoperative clinical and laboratory findingsere unremarkable (Table 1). During the operation, no

omplications were observed. On postoperative day 2, se-um creatinine level increased to 5.0 mg/dL (445 �mol/L).

From the 1Clinic for Transplantation Immunology andephrology, 2Department of Urology, and 3Institute of Clini-al Pathology, University Hospital, Basel, Switzerland.

Received August 15, 2007. Accepted in revised formovember 29, 2007. Originally published online as doi:0.1053/j.ajkd.2007.11.031 on February 29, 2008.

Address correspondence to Michael Mayr, MD, Clinicor Transplantation Immunology and Nephrology, Univer-ity Hospital Basel, CH-4031 Basel, Switzerland. E-mail:mayr@uhbs.ch© 2008 by the National Kidney Foundation, Inc.0272-6386/08/5104-0035$34.00/0

doi:10.1053/j.ajkd.2007.11.031

p e19-e24 e19

AihOsw

P

tsuwidmawop

P

whu11

AttaoiodfF

H

wTmvcapfciucad

AKDI

IB

C

S

H

N

t ply by 1

Kim et ale20

symptomatic hyponatremia was present and persisted dur-ng the next 6 days. The patient became oliguric, and acuteemodialysis therapy was required on postoperative day 8.n day 7, we performed a kidney biopsy. After 3 hemodialy-

is sessions, kidney function showed incomplete recoveryithin 1 month (Table 1; Fig 1A).

atient 2A 74-year-old man was admitted for KTP laser vaporiza-

ion of the prostate because of obstructive prostate hyperpla-ia. On admission, physical and laboratory findings werenremarkable (Table 1). No intraoperative complicationsere observed. He experienced transient nausea and vomit-

ng postoperatively. On postoperative day 1, the patienteveloped oliguria and had a serum creatinine level of 4.1g/dL (362 �mol/L). On postoperative day 3, acute hemodi-

lysis was required because of pulmonary congestion andas continued for 2 weeks. A kidney biopsy was performedn postoperative day 5. Kidney function recovered incom-letely within 1 month (Table 1; Fig 1B).

atient 3A 61-year-old man with obstructive prostate hyperplasia

as admitted for KTP laser vaporization of the prostate. Head autosomal dominant polycystic kidney disease and hadndergone successful living donor kidney transplantation.5 months earlier. Serum creatinine level decreased from

Table 1. Preoperative and Posto

ge (y)idney typeuration of operation (min)

rrigation fluidIntraoperativePostoperative

rrigation pressure (mm Hg)lood pressure (mm Hg); heart rate (beats/min)PreoperativeAt end of surgery 1reatinine (mg/dL)On admissionHighest levelAt 1-mo follow-upAt last follow-upLast follow-up (mo)

odium (mEq/L)On admissionOn day 1Lowest levelemoglobin (g/dL)On admissionPostoperativeo. of hemodialysis treatments

Note: Purisol (Fresenius Kabi, Bad Homburg, Germany) io �mol/L, multiply by 88.4; hemoglobin in g/dL to g/L, multi

2.3 mg/dL (1,088 �mol/L) to 1.5 mg/dL (132 �mol/L). n

bout 7 weeks later, he presented with acute urinary reten-ion caused by prostate hyperplasia. On admission for pros-ate surgery, physical and laboratory findings were unremark-ble (Table 1). No complications were observed during theperation. On postoperative day 1, serum creatinine levelncreased to 3.3 mg/dL (296 �mol/L) and the patient becameliguric. A kidney biopsy was performed on postoperativeay 3. No acute dialysis therapy was required, and kidneyunction recovered incompletely within 1 month (Table 1;ig 1C).

istological FindingsMorphological lesions shown in all 3 biopsy specimens

ere very similar and therefore can be described together.hey were confined to the tubulointerstitial space and wereore pronounced in the cortex than in the medulla. Blood

essels and glomeruli (also studied by using electron micros-opy in 1 patient) showed no changes. Lesions were patchynd comprised interstitial edema and tubular dilatation withartial loss of the brush border in proximal tubules (Fig 2). Aew tubules contained cell debris and showed minor tubularell necroses, as well as Tamm-Horsfall stasis (extendingnto Bowman space in 1 patient). A few irregularly distrib-ted cellular infiltrates were seen in the interstitial space,omposed of lymphocytes, histiocytes, a few eosinophils,nd neutrophils (mainly surrounding tubules containing cellebris). Special staining for hemoglobin and myoglobin had

ve Laboratory and Clinical Data

nt 1 Patient 2 Patient 3

74 61ive Native Transplant

45 60

water Sterile water Sterile waterisol Purisol Purisol00 60-100 60-100

0; 68 120/70; 64 140/80; 72; 54-70 160/100; 50-60 150/85; 65-75

.2 0.8 1.4

.3 9.6 5.6

.6 1.7 2.5

.0 1.1 2.011 17

140 150ay 2) 130 133

130 133

.8 15.7 14.3

.1 12.3 13.29 0

tol-mannitol solution. To convert serum creatinine in mg/dL0. Sodium in mEq/L and mmol/L is equivalent.

perati

Patie

76Nat150

SterilePur60-1

140/665/95

11122

25

133119 (d

115

13122

s sorbi

egative results. Standard immunohistochemistry for immu-

nrnTser

byKef

whlemoavl

trs

aspvtmbmte

Acute Renal Failure After Prostate Vaporization e21

oglobulins and complement factors gave weak unspecificesults. In all 3 patients, the diagnosis of acute tubularecrosis was made without evidence of irreversible damage.he combination of lesions, edema, Tamm-Horsfall proteintasis and regurgitation, and few tubular cell necroses andosinophils is best interpreted as the result of acute urinaryeflux into the kidney.

DISCUSSION

The KTP:yttrium-aluminum-garnet laser isased on the principle of passing neodymium:ttrium-aluminum-garnet laser light through aTP crystal that halves the wavelength of the

mitted laser to 532 nm and thus doubles its

-1112 -87 -42 -1

0123456789

101112

1.3 1.2 1.2 1.

creatinine(mg/dL)

laser vaof prost

A

-1 1

0

1

2

3

4

5

6

7

8

9

10

0.8

4.1

6

creatinine

(mg/dL)

laser vapoof prostate

B

-49 -41 -27

0

2

4

6

8

10

12

1412.3

1.5 1.5

DJ-cathinsertio

creatinine

(mg/dL)

C

Figure 1. (A-C) Course ofcute renal failure after potas-ium-titanyl-phosphate laser va-orization of prostate. To con-ert serum creatinine in mg/dLo �mol/L, multiply by 88.4; he-oglobin in g/dL to g/L, multiplyy 10. Sodium in mEq/L andmol/L is equivalent. Abbrevia-

ions: HD, hemodialysis; DJ cath-ter, double-J catheter.

requency. The emitted light is visible green, g

hich is strongly absorbed by red tissues andemoglobin. Selective absorption of the greenight laser by hemoglobin leads to trapping of thenergy in the superficial area of tissues (only 0.8m deep) and causes heat-induced coagulation

f superficial blood vessels and consequently anlmost bloodless field.6 Differences between con-entional TURP and KTP laser vaporization areisted in Table 2.

Bachmann et al8 and Malek et al9 reportedransient dysuria, transient urinary incontinence,ecatheterization, urinary tract infection, urethraltricture, bladder neck contracture, and retro-

4 6 8 10 11 13 18 27 36 406 770

7.9

9.8

11.3

7.4

4.85.9

3.82.6

1.9 1.7 2

HD

kidney biopsytion

day

day4 6 11 15 17 19 30 51 336

.3

9.6 9.4

5.8

4.73.8

1.71.1 1.1

n

HD

kidney biopsy

1 -8 0 1 4 8 126 491 513 518 531

.4 1.9 1.4

3.3

5.6

3.41.9 1.9 1.5 1.7 2

acute urinary retention

laser vaporizationof prostate

kidney biopsy

day

2

2

5

porizaate

3

.47

rizatio

-12 -1

2.6 2

etern

rade ejaculation as postoperative complica-

tp3cdoqtSAt

atidoegjhaa

IIRP

IOC

Kim et ale22

ions. However, there was no report of ARF inatients treated with KTP laser vaporization. Our

patients showed almost identical diseaseourses. Renal failure occurred on postoperativeay 1, all patients were oligoanuric and devel-ped asymptomatic hyponatremia, 2 patients re-uired hemodialysis therapy, and kidney func-ion recovered incompletely within 1 month.winney and Tomlinson10 reported 6 cases ofRF in association with transurethral prostatec-

omy. They postulated a relationship between

Table 2. Perioperative Differences Between

rrigation fluid Sorbitol-manntravesical pressure (mm Hg)isk of fluid absorptionostoperative bladder irrigation to preventblood clotting

ntraoperative irrigation fluid volume (L)† 2peration time (min)† 5atheterization time (d)†

Note: Values expressed as mean � SD.Abbreviations: TURP, transurethral resection of the pros*Sugar-containing solution should be avoided because o

†Results from own series including 127 patients with TURP and

bsorption of irrigating fluid and prostatic secre-ion into the blood stream and histological find-ngs. In our 3 patients, decreases in serum so-ium levels were remarkable. Thus, absorptionf a certain amount of irrigation fluid cannot bexcluded. In association with absorption of irri-ating fluid, renal tissue edema and tubular in-ury caused by fluid shift as a consequence ofyponatremia were postulated to cause ARF.4 Asdditional pathogenic mechanisms, release andbsorption of prostatic substances and endotox-

Figure 2. (A) Glomeruluswith Tamm-Horsfall protein inBowman space. (B) Dilated tu-bules with flattened epithelium,partial loss of brush border, tubu-lar cell mitosis, and edematousinterstitial space. (C) Eosino-phils and lymphocytes in theedematous interstitial space. Tu-bular epithelium with signs of de-generation. (D) Highly edema-tous interstitial space withactivated fibroblasts close to thecorticomedullary junction ([A] Pe-riodic acid–Schiff stain; [B-D] he-matoxylin and eosin stain; [A-D]original magnification �400).

and KTP Laser Vaporization of the Prostate

KTP Laser Vaporization

lution (Purisol) Sodium chloride 0.9% or sterile water*0 60-100

Lowar Less frequent

.8 13.1 � 6.25.7 72.3 � 27.3.5 1.7 � 1.3

P, potassium-titanyl-phosphate.k of caramelization on the laser fiber.

TURP

TURP

nitol so60-10High

Regul

6.9 � 92.9 � 12.8 � 1

tate; KTf the ris

269 patients with KTP laser vaporization of the prostate.

iaaKflevpssfiplateam1tenacceiT

hnwavhiucvmaib1cpcplfp

ciecolteeii

cpvesbTaap

p

ft

ta

A

p

b

Ptc

vp

poJ

a

Acute Renal Failure After Prostate Vaporization e23

ns, as well as hypovolemia caused by natriuresisfter transient hypervolemia, osmotic diuresis,nd fluid shift were discussed.4 In the case ofTP laser vaporization, absorption of irrigatinguid should be minimal. Reich et al11 showed inx vivo perfused porcine kidneys that KTP laseraporization was a virtually bloodless ablativerocedure. In addition, the absence of fluid ab-orption during KTP laser vaporization was de-cribed in canines and humans. However, thesendings were based on only lack of change inreoperative and postoperative serum sodiumevels and hematocrits.7,9,12,13 Both parametersre influenced by the amount of infusion and alsohe sodium concentration in solutions. Lower lev-ls of absorption may be missed easily.4 Barber etl14 used the highly sensitive technique of ethanoleasurement in expired breath after adding ethanol

% to the irrigating fluid to monitor fluid absorp-ion during KTP laser vaporization. In 40 patients,xpired breath ethanol was zero.14 Barber et al14

oticed only 1 case of significant fluid absorptionfter KTP laser vaporization in a patient who had aapsular perforation. In our patients, such a compli-ation was not observed. Gray et al5,15 showedxcessive intravesical pressure as a risk factor forrrigating fluid absorption during conventionalURP and transurethral vaporization.Although not discussed in previous reports,

igh intravesical pressure also may lead to uri-ary stasis and transient vesicoureteral refluxith backflow of irrigating fluid, hemoglobin,

nd prostate secretion. During TURP and laseraporization, irrigation pressure usually is muchigher than physiological intravesical pressure. Dur-ng micturition, intravesical pressure increases, butsually does not exceed 25 mm Hg.16 Duringonventional TURP and laser vaporization, intra-esical pressures were regulated by using an auto-atic pressure pump. Pressure of 60 mm Hg was

imed to be optimal. However, real-time changesn pressure were possible. In our patients, theladder was irrigated at pressures of around 60 to00 mm Hg. Urinary stasis and transient vesi-oureteral reflux resulting from high intravesicalressure may directly damage the kidney andause ARF. Interestingly, biopsy findings in ouratients were similar. The patchy character of theesion and the combination of interstitial edema,ew tubular cell necroses, and Tamm-Horsfall

rotein stasis with regurgitation into Bowman 5

apsule accompanied by some eosinophils in thenterstitial infiltrate favor the assumption of anpisode of acute urinary reflux into the kidney. Inase of ischemic damage, a more diffuse patternf tubular dilatation with loss of brush border,ess edema, no prominent Tamm-Horsfall pro-ein stasis, and no eosinophils would have beenxpected. Thus, a local “hit” damaging tubularpithelial cells in a direct way seems to benvolved in the pathogenic mechanisms operat-ng in our patients.

In conclusion, we present 3 cases of ARF as aomplication of continuous flow irrigation inatients treated with KTP laser vaporization, aery efficient laser procedure in terms of intraop-rative hemostasis. Histological findings stronglyuggest direct damage of the tubular epitheliumy urinary stasis and backflow of irrigating fluid.hus, intravesical pressure should be kept as lows possible during transurethral prostate surgery,lthough the risk of fluid absorption during laserrostatectomy is very low.

ACKNOWLEDGEMENTSSupport: None.Financial Disclosure: None.

REFERENCES1. Creevy CD: Hemolytic reactions during transurethral

rostatic resection. J Urol 58:125-131, 19472. Hung C, Wu C, Yang S, Chen H, Lin J: Acute renal

ailure directly caused by hemolysis associated with transure-hral resection of the prostate. Urology 59:137ix-137pxii, 2002

3. Bauer JH, Vopat RL, Wanner P, Hayes A: Posttransure-hral prostatic resection hyponatremic syndrome: Case reportnd review of the literature. Am J Kidney Dis 4:80-84, 1984

4. Hahn RG: Fluid absorption in endoscopic surgery. Br Jnaesth 96:8-20, 20065. Gray RA, Lynch C, Hehir M, Worsley M: Intravesical

ressure and the TUR syndrome.Anaesthesia 56:461-465, 20016. Elzayat EA, Elhilali MM: Laser treatment of symptomatic

enign prostatic hyperplasia. World J Urol 24:410-417, 20067. Kuntzman RS, Malek RS, Barrett DM, Bostwick DG:

otassium-titanyl-phosphate laser vaporisation of the pros-ate: A comparative functional and pathologic study inanines. Urology 48:575-583, 1996

8. Bachmann A, Ruszat R, Wyler S, et al: Photoselectiveaporization of the prostate: The Basel experience after 108rocedures. Eur Urol 47:798-804, 20059. Malek RS, Kuntzman RS, Barrett DM: Photoselective

otassium-titanyl-phosphate laser vaporization of the benignbstructive prostate: Observations on long-term outcomes.Urol 174:1344-1348, 200510. Swinney J, Tomlinson BE: Lower nephron nephrosis

fter transurethral resection of the prostate. J Clin Pathol

:234-238, 1952

tpt

tf1

pt

Meso

ua

a

Kim et ale24

11. Reich O, Bachmann A, Schneede P, et al: Experimen-al comparison of high power (80 W) potassium titanylhosphate laser vaporization and transurethral resection ofhe prostate. J Urol 171:2502-2504, 2004

12. Hai MA, Malek RS: Photoselective vaporization ofhe prostate: Initial experience with a new 80 W KTP laseror the treatment of benign prostatic hyperplasia. J Endourol7:93-96, 200313. Malek RS, Kuntzmann RS, Barrett DM: High power

otassium-titanyl-phosphate laser vaporization prostatec-

omy. J Urol 163:1730-1733, 2000 P

14. Barber N, Zhu G, Donohue J, Thompson P, Walsh K,uir G: Use of expired breath ethanol measurements in

valuation of irrigant absorption during high-power potas-ium titanyl phosphate laser vaporization of prostate. Urol-gy 67:80-83, 200615. Gray RA, Moores AH, Hehir M, Worsley M: Trans-

rethral vaporisation of the prostate and irrigating fluidbsorption. Anaesthesia 58:787-791, 2003

16. Arant BS Jr: Vesicoureteral reflux and reflux nephrop-thy, in Greenberg A (ed): Primer on Kidney Disease (ed 4).

hiladelphia, PA, Elsevier Saunders, 2005, pp 399-403