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| Year : 2004 | Volume
: 15
| Issue : 3 | Page : 300-304 |
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| Ultrasound-guided Biopsy of Native and Transplanted Kidneys |
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Sydney Tang, Kar Neng Lai
Division of Nephrology, University Department of Medicine, Queen Mary Hospital, Hong Kong, China
Click here for correspondence address and email
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 Abstract | | |
Percutaneous renal biopsy is a valuable tool in the definitive diagnosis of a variety of kidney diseases. Advances in the design of biopsy needles as well as the availability of real-time ultrasound guidance for the procedure, has greatly reduced complication rates. In this review, we summarize the contemporary practice of real-time ultrasound-guided percutaneous biopsy of the native and transplant kidneys. Practical tricks in enhancing this method of biopsy are presented. Non-percutaneous techniques in specific settings are also discussed.
How to cite this article:
Tang S, Lai KN. Ultrasound-guided Biopsy of Native and Transplanted Kidneys. Saudi J Kidney Dis Transpl 2004;15:300-4 |
| Introduction | |  |
Percutaneous renal biopsy is the definitive choice of investigation for many forms of renal parenchymal diseases, including those of the transplanted kidney. The procedure may be required for various reasons, including the establishment of the underlying renal pathology, as an aid to determine therapy, as a guide to prognosis, and to ascertain the degree of acute or potentially reversible versus chronic or practically irreversible damages. [1] Nowadays, most centres routinely subject biopsied renal tissue for examination under light microscopy. Depending on the level of diagnostic certainty and the amount of kidney tissue obtained, immunofluorescence, and electron microscopic examination may ensue. The use of the Franklin-modified VimSilverman needle for percutaneous renal biopsy under fluoroscopy [2] has in recent years been replaced by the use of disposable needles under real-time ultrasonographic guidance. In this article, we review the literature on the use of this technique in performing renal biopsies in adult subjects.
| Indications and Contraindications | | |
The policy and threshold for performing a renal biopsy vary considerably among different centers and nephrologists. In general, there are five categories of indications: [3]
a) Glomerular hematuria
b) Non-nephrotic range protenuria
c) Nephrotic syndrome
d) Acute nephritic syndrome
e) Acute or subacute renal failure of undetermined origin
Percutaneous renal biopsy is generally considered contraindicated in the following settings:
a) Uncorrectable bleeding diathesis
b) Small (less than 8-9 cm in length) or echogenic kidneys, which are generally indicative of chronic irreversible disease
c) Intractable hypertension, which cannot be controlled with antihypertensive medications
d) Multiple, bilateral cysts or any sizeable space-occupying lesion, e.g. renal tumor
e) Significant hydronephrosis
f) Active infection of the urinary tract, especially pyelonephritis
g) An uncooperative patient
| Preparation of the Patient for Renal Biopsy | | |
An informed consent should be obtained prior to the procedure. Since bleeding is the principal complication of renal biopsy, prebiopsy evaluation should aim to exclude the presence of coagulopathy (prolongation of the prothrombin time, or the partial thromboplastin time) and thrombocytopenia (platelet count < 150 x 10 9 /L). Any use of aspirin, warfarin, or nonsteroidal anti-inflammatory drugs must be stopped at least one week prior to a scheduled elective renal biopsy. Blood pressure should be maintained at 140/90 mm Hg or below. In our experience, some patients become hypertensive due to anxiety on the morning of the scheduled biopsy despite a previously well-controlled blood pressure. An oral dose of nifedipine (5-10 mg) usually helps. Patients with elevated serum creatinine (e.g. over 300 µmol/l) should be considered for desmopressin infusion (0.3 µg/kg i.v. over 30 minutes) before and after the procedure to reduce the risk of uremic bleeding. [4] The skin overlying the biopsy site should be inspected for signs of infection. In addition, the patient should be able to lie prone and follow simple commands, such as temporary breath-holding. An intravenous access should be established. Appropriate cross matching of blood should be arranged with the blood bank, although the need for immediate blood transfusion after renal biopsy is seldom encountered. In general, overnight fasting is not required.
| Biopsy Procedure | | |
The patient is positioned lying face down with abdominal compression, e.g. using a pillow placed beneath the abdomen. For transplant kidney biopsies, the patient remains in the supine position. The biopsy is either performed in the ultrasound suite (or occasionally by the bedside with a "portable" ultrasound machine) by the nephrologist alone, or together with a radiologist. The ultrasound machine and the operator are positioned to the left of the patient for the native kidney, or to the side of the allograft for the transplant kidney. Ultrasonography is carried out at this point to determine renal size and echogenicity, ascertain the presence of two native kidneys (to exclude congenital renal aplasia or hypoplasia on one side), detect the presence of cysts that might necessitate using the contralateral kidney or, the presence of hydronephrosis or small and echogenic kidneys that will prompt the abandoning of the procedure. The choice of ultrasound probe is variable. We recommend a four MHz sector transducer for the native kidney, or a five MHz linear probe for the transplant kidney.
After excluding contraindications, one should localize the desired lower pole site (that minimizes the risk of puncturing a major vessel) and estimate its depth to determine the length of the biopsy needle required. At this time, the patient may be instructed to take several "practice" breathholding maneuvers at the desired phase and level of respiration. For the sake of convenience, we usually approach the left kidney first, and only biopsy the right kidney if there are unexpected lesions on the left. A skin mark or impression (which may be conveniently cast with a needle cap) is made to identify the subsequent site of biopsy needle insertion. The skin is then disinfected and locally anaesthetized with 1% lignocaine. Under ultrasound guidance, a 22G spinal needle is then used to locate the capsule of the lower pole and to provide anesthesia along the visible path of the anticipated biopsy needle entry. This will greatly alleviate any muscle spasm due to pain that may otherwise render the procedure more difficult. A small stab wound is then made to facilitate subsequent passage of the biopsy needle.
A variety of different biopsy needles are available, but the most commonly used are either the disposable hand-driven TruCut™ (14G), or the automated spring-loaded biopsy needles (16 or 18G). [5] The choice of biopsy needle is largely one of individual preference, although the larger TruCut™ needle was associated with a modest increase in the number of glomeruli per core and a trend toward a greater degree of significant bleeding and a more pronounced fall in hematocrit. [6],[7] The choice of needle is also partly determined by the number of operators and the kidney to be biopsied. In the presence of two persons, one can use either the TruCut or spring-loaded needle. The mounting of a needle guide on to the ultrasound probe is optional. With the radiologist positioning the probe optimally for real-time guidance, the nephrologist advances the needle to a depth deemed by the radiologist to be desirable for biopsy. The patient is instructed to hold his or her breath at the desired level of inspiration. The operator should feel a "give" after the needle tip traverses the renal capsule, and the actual biopsy should be performed at this point. If the nephrologist is the sole operator, the automated needle must be used. The left hand holds the ultrasound probe for real-time guidance, while the right hand holds the biopsy needle and advances it to the desired level for "firing" (unloading of the spring). The patient should be instructed to resume normal breathing once the biopsy is obtained, and light pressure should be applied to the puncture site. A second core may then be obtained. Indeed, it is common practice to obtain at least two cores of renal tissue. [8]
In the ideal situation, a pathologist should be in the vicinity to examine the biopsied tissue under a dissecting microscope to have a rough count of the number of glomeruli present. A joint decision is made as to whether an additional core is appropriate, which depends not only on tissue adequacy, but also on patient tolerability and the emergence of possible complications. For the transplant kidney, we recommend the use of the smaller automated spring-loaded needle. Real-time ultrasound guidance is performed as described, and the more accessible pole of the allograft is approached. Breath-holding is not necessary.
| Post-Biopsy Monitoring | | |
All patients should be instructed to lie in the supine position for up to 24 hours after renal biopsy. This is important because, regarding renal biopsy as an out-patient procedure with observation for eight hours or less, one may miss up to 33% of complications. [9] Thus, we and others recommend that patients should be hospitalized overnight for monitoring of vital signs, [9],[10] in contradiction to earlier reports that it was safe and economical to perform renal biopsy as a day-care or out-patient procedure. [11],[12] Blood pressure and heart rate are recorded hourly for the initial six hours, then fourhourly if stable. All voided urine should be collected in serial test-tubes for inspection and monitoring of macroscopic hematuria, if present. If any one of these parameters is abnormal (e.g. tachycardia, gross hematuria, or hypotension), a complete blood count should be obtained urgently. A colour-coded Doppler ultrasonography may be performed as clinically indicated to look for the occurrence of perinephric hematoma or the formation of an arterio-venous fistula. In the absence of a positive ultrasonographic finding and where clinically indicated (e.g. hemodynamic instability), a renal arteriogram with a view to embolizing the "culprit bleeder" may be carried out.
| Complications | | |
Despite measures to minimize complications of renal biopsy, bleeding is still the most common complication observed. In our series of over 200 procedures, [10] mild hematuria occurred in 4.5%, while major complications (those that required blood transfusion or other intervention such as arteriogram and embolization) were encountered in 1.5% of the patients. The presence of systemic hypertension or nephrotic syndrome did not increase the risk of bleeding. There was no correlation between bleeding and the type of renal pathology or the number of needle passes. Impaired renal function was identified as the single most important risk factor of significant bleeding after renal biopsy, which is confirmed by a recent study on a large cohort of 750 patients. [9] Patients with a serum creatinine > or = 5.0 mg/dl were 2.3 times more likely to have a complication. Furthermore, in this series, the prevalence of major and minor complications was reported to be 6.4% and 6.6%, respectively. Minor complications were defined as those resulting in gross hematuria and/or perinephric hematoma but spontaneously resolving without the need for further intervention. Major complications were those resulting in the need for an intervention, such as a transfusion of blood products or invasive procedure (radiographic or surgical), and those resulting in acute renal obstruction or failure, septicemia, or death.
Transient microscopic hematuria is almost inevitable. More serious bleeding may give rise to: (a) gross hematuria and possible ureteral obstruction or clot retention in the bladder due to hemorrhage into the collecting system; (b) subcapsular hematoma, leading to pressure tamponade and pain; or (c) perinephric hematoma, which may potentially cause a large fall in hematocrit due to the relative lack of tamponade effect. Most of these complications occur within 24 hours of the procedure, although delayed subcapsular hematoma occurring one week later has been observed. Hematuria and hematoma formation are usually self-limiting, and tend to subside with bed rest. The need for selective arterial embolization is around 1.5%. Surgery is required to control the bleeding in 0.1 to 0.4% with a nephrectomy rate of roughly 0.06%.[5]
Arterio-venous fistulae are due to damage to the walls of an adjacent artery and vein.[1],[13] Post-biopsy fistulae are usually clinically silent and resolve spontaneously over time. Symptomatic fistulae, causing hematuria, hypotension, or high-output heart failure, are now rare. The diagnosis can be established by color Doppler ultrasonography or arteriography. [13] Another rare complication is the "Page kidney", [14],[15] which results from pressure-induced ischemia due to a large subcapsular hematoma, leading to persistent activation of the renin-angiotensin system and hypertension. We have not encountered this complication in our series of over 1,000 biopsies over the last 10 years.
| Non-percutaneous Renal Biopsy Techniques | | |
Laparoscopic renal biopsy [16] should be considered for a solitary kidney or in the extremely obese patient in whom the percutaneous approach is technically impossible.
General anesthesia is usually required, although it can also be performed on an out-patient basis.
Transjugular renal biopsy is a newer technique in which the renal capsule is not penetrated and the risk of subcapsular or perinephric bleeding is eliminated. [17],[18] The major indications for this modality are uncorrectable bleeding diathesis. Due to the radiologic expertise required for transjugular biopsy, it is not suitable for routine purposes, despite its lower bleeding risk.
| References | | |
| 1. | Madaio MP. Renal biopsy. Kidney Int 1990; 38:529-43.  [PUBMED] |
| 2. | Almkuist RD, Buckalew VM Jr. Techniques of renal biopsy. Urol Clin North Am 1979; 6:503-17. |
| 3. | Fuiano G, Mazza G, Comi N, et al. Current indications for renal biopsy; a questionnaire-based survey. Am J Kidney Dis 2000; 35:448-57. [PUBMED] |
| 4. | Weigert AL, Schafer AI. Uremic bleeding: pathogenesis and therapy. Am J Med Sci. 1998;316:94-104. |
| 5. | Korbet SM. Percutaneous renal biopsy. Semin Nephrol 2002; 22:254-67. [PUBMED] |
| 6. | Doyle AJ, Gregory MC, Terreros DA. Percutaneous native renal biopsy: comparison of a 1.2-mm spring-driven system with a traditional 2-mm hand-driven system. Am J Kidney Dis 1994;23:498-503. |
| 7. | Riehl J, Maigatter S, Kierdorf H, Schmitt H, Maurin N, Sieberth HG. Percutaneous renal biopsy: comparison of manual and automated puncture techniques with native and transplanted kidneys. Nephrol Dial Transplant. 1994;9:1568-74. |
| 8. | Appel GB. Renal biopsy: how effective, what technique, and how safe. J Nephrol 1993;6:4-9. |
| 9. | Whittier WL, Korbet SM. Timing of complications in percutaneous renal biopsy. J Am Soc Nephrol 2004;15:142-7. [PUBMED] [FULLTEXT] |
| 10. | Tang S, Li JH, Lui SL, Chan TM, Cheng IK, Lai KN. Free-hand, ultrasound-guided percutaneous renal biopsy: experience from a single operator. Eur J Radiol 2002;41:65-9. [PUBMED] [FULLTEXT] |
| 11. | Murphy BF, MacIsaac A. Percutaneous renal biopsy as a day-patient procedure. Am J Kidney Dis 1989;14:77. [PUBMED] |
| 12. | Maddux FW, Maddux DW, Starling JF, et al. Outpatient renal biopsy is a safe procedure in the community setting [Abstract]. J Am Soc Nephrol 1992;3:345A. |
| 13. | Harrison KL, Nghiem HV, Coldwell DM, Davis CL. Renal dysfunction due to an arteriovenous fistula in a transplant recipient. J Am Soc Nephrol 1994:5:1300-6. |
| 14. | Haydar A, Bakri RS, Prime M, Goldsmith DJ. Page kidney--a review of the literature. J Nephrol 2003;16:329-33. [PUBMED] [FULLTEXT] |
| 15. | Bakri RS, Prime M, Haydar A, Glass J, Goldsmith DJ. Three 'Pages' in a chapter of accidents. Nephrol Dial Transplant. 2003;18:1917-9. |
| 16. | Gupta M, Haluck RS, Yang HC, Holman MJ, Ahsan N. Laparoscopic-assisted renal biopsy: an alternative to open approach. Am J Kidney Dis 2000;36:636-9. [PUBMED] |
| 17. | Mal F, Meyrier A, Callard P, Kleinknecht D, Altmann JJ, Beaugrand M. The diagnostic yield of transjugular renal biopsy. Experience in 200 cases. Kidney Int 1992;41:445-9. |
| 18. | Stiles KP, Yuan CM, Chung EM, Lyon RD, Lane JD, Abbott KC. Renal biopsy in highrisk patients with medical diseases of the kidney. Am J Kidney Dis 2000;36:419-33. [PUBMED] |
Correspondence Address:
Sydney Tang
Division of Nephrology, University Department of Medicine, Queen Mary Hospital, Hong Kong
China
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PMID: 18202480 
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