High incidence of arteriovenous fistula after biopsy of kidney allografts

[Renal Biopsy]

The extent of renal biopsy indication is being widened because of the increasing incidence of incidental renal masses; the increasing treatment options for renal cell carcinoma, including ablation therapy and novel targeted treatment; and the increasing incidence of kidney transplantation. However, percutaneous renal biopsy is technically difficult, particularly for beginners, because the skin-to-organ distance is relatively longer than those associated with other organs. In the present review, we will discuss the indications, technical considerations, efficacy, and complications of renal biopsy. Furthermore, we share practical tips of renal biopsy through many examples to help radiologists perform renal biopsy safely and effectively in various situations.

Arteriovenous fistula in a renal allograft with gross hematuria and subsequent acute kidney injury due to urinary tract obstruction: a case report

BACKGROUND

Arteriovenous fistula (AVF) due to renal allograft biopsy is mechanical trauma resulting from the penetration of small arteries and veins by a core needle. Most AVFs are reported to resolve asymptomatically and spontaneously. This report presents a patient with acute kidney injury (AKI) due to urinary tract obstruction caused by a bleeding AVF in a renal allograft.

CASE PRESENTATION

A 22-year-old Japanese woman who underwent living-donor kidney transplantation (KT) at 3 years due to end-stage renal disease caused by focal segmental glomerulosclerosis (FSGS) presented with a renal transplant AVF (gourd-shaped; 42 × 19 × 20 mm). The AVF was unexpectedly discovered by ultrasound before a surveillance biopsy at 10 years after KT. The patient had a history of recurrent FSGS, had undergone several renal allograft biopsies after KT, and did not experience symptoms or growth of the AVF for years. Nineteen years after KT, the patient developed AKI with sudden, asymptomatic, gross hematuria and anuria. Plain computed tomography revealed a hematoma in the pelvis of the renal allograft and bladder tamponade. The AVF was successfully treated by coil embolization. Hemodialysis was performed for AKI, and graft function was gradually recovered.

CONCLUSIONS

Unexpected bleeding from a renal transplant AVF may lead to transplant dysfunction. Angiographic embolization against the ruptured renal transplant AVF may prevent rebleeding and rescue the renal allograft.

Renal arteriovenous fistula discovered ~2 years after renal biopsy: A case report

Key Clinical Message

Although percutaneous renal biopsy is considered safe, this invasive procedure has complications such as renal arteriovenous fistula (RAVF). Even if complications such as RAVFs are not observed early after renal biopsy, considering the possibility of delayed renal hemorrhage, follow-up with ultrasound after renal biopsy even in asymptomatic cases could be important.

Abstract

Although percutaneous renal biopsy is considered safe, this invasive procedure can lead to complications such as renal arteriovenous fistula (RAVF). RAVF occurs when some arteries and veins communicate in the absence of capillaries in the renal hilum or renal parenchyma. It was previously thought to be relatively rare; however, with advances in imaging diagnostics, it is sometimes found asymptomatically. In addition, renal biopsy is the most common cause of acquired RAVF. In this case, RAVF was discovered 2 years after renal biopsy. Late-onset RAVF is scarce. This case highlights that even if complications such as RAVFs are not observed early after renal biopsy, considering the possibility of delayed RAVF, follow-up with ultrasound could be important.

Postoperative and Recurrent Hematuria after Pretransplant Core Needle Biopsy in Living Donor Kidney Transplant

Background

Core needle and wedge biopsies are the two main pathologic ways to determine the suitability of a kidney allograft and to have a baseline allograft biopsy in case of future rejection. Case Presentation. A 57-year-old patient developed a renal arteriovenous fistula causing postoperative and recurrent hematuria after allograft pretransplant renal core needle biopsy and treated with selective Interventional radiology coil embolization.

Conclusion

Delayed profound hematuria can be seen after pretransplant core needle renal biopsies and can recur again even after complete resolution, due to arteriovenous fistula formation in the renal calyceal system.

Complications of renal interventions: a pictorial review of CT findings

A number of potential vascular and non-vascular complications can arise from surgical, extracorporeal shock wave lithotripsy, radiotherapy and radiological renal interventions, including percutaneous image-guided biopsy and drainage. Computed tomography scan is usually one of the first and most important diagnostic imaging examinations requested when a potential complication is suspected. There are a wide range of common and uncommon potential complications from renal interventions. An understanding of underlying risk factors is important to reduce potential complications from renal intervention. Radiologists play a crucial role in recognising and diagnosing post-renal intervention complications on computed tomography scans, which could significantly improve the patient’s prognosis.

Renal arteriovenous fistula after renal biopsy: a case report and literature review

Acquired renal arteriovenous fistulas (AVF) are rare conditions in which an anomalous connection arises between the arterial and venous systems. Renal AVFs can be classified into three main groups: idiopathic, congenital, and acquired, the last of which are the most common. Incidence has been increasing, due to the growing number of renal biopsies. Although the renal biopsy procedure is relatively safe nowadays, one possible complication is formation of an AVF in the renal vascular territory. Treatment of renal AVF is widely discussed in the literature and a variety of treatment methods can be employed. We report a case of arteriovenous fistula after renal biopsy that was successfully treated with endovascular coil embolization.

Dual-balloon assisted super-selective embolisation of high flow arterial venous fistula within a transplant kidney

Background

In this case report, we describe a novel application of the technique of ‘dual-balloon assisted’ cannulation and embolisation of a high flow arterial venous fistula (AVF) in transplant kidney, where attempts at standard and previously described embolisation techniques were proving difficult to achieve.

Case presentation

Seventy year old gentleman with renal transplant presenting with high output cardiac failure and deteriorating renal function. Angiography demonstrated high flow traumatic AV fistula within transplanted kidney, secondary to multiple biopsies. Attempts at guidewire and guiding sheath placement and stability for occlusion plug deployment were failing due to combination of very high back-flow pressures within the AVF and challenging vascular anatomy; with an aneurysmal, tortuous iliac artery as well as intra renal transplanted vessels. A combination of angioplasty and remodeling aortic balloons in the transplant artery and the host external iliac vein respectively, facilitated stabilization of guiding sheath and hence controlled delivery of an occlusion plug from the venous side of the fistula. The fistula was successfully embolised, leading to complete resolution of patient symptoms and improvement of renal function beyond his previous baseline.

Conclusions

Percutaneous embolisation is an established technique to treat iatrogenic AVF in transplant kidneys. High flow pressure through an AVF, as demonstrated in this case, can cause difficulty and raise safety issues in accessing and embolising the AVF using previously described techniques. This case report describes an effective and novel application of the technique of using a second balloon in the host common iliac vein to; lower flow pressure, stabilise the guidewires during plug deployment and prevent displacement of wires and/or plug into the common iliac vein.

Endovascular Stent-graft Repair of Combined Renal Artery Aneurysm and Arteriovenous Fistula

Renal artery aneurysm with concomitant presence of arteriovenous fistula is an extremely rare entity. Few reports have been described in the literature. Nowadays, endovascular repair with covered stents or transarterial embolization with coils or glue has become the first line of treatment. We present the successful repair of a distal renal artery aneurysm combined with arteriovenous fistula with stent graft.

Arteriovenous fistulae after renal biopsy: diagnosis and outcomes using Doppler ultrasound assessment

BACKGROUND

Percutaneous renal biopsy (PRB) is an important technique providing relevant information to guide diagnosis and treatment in renal disease. As an invasive procedure it has complications. Most studies up to date have analysed complications related to bleeding. We report the largest single-center experience on routine Doppler ultrasound (US) assessment post PRB, showing incidence and natural history of arteriovenous fistulae (AVF) post PRB.

METHODS

We retrospectively analysed 327 consecutive adult PRB performed at Ramon Cajal University Hospital between January 2011 and December 2014. All biopsies were done under real-time US guidance by a trained nephrologist. Routine Doppler mapping and kidney US was done within 24 h post biopsy regardless of symptoms. Comorbidities, full blood count, clotting, bleeding time and blood pressure were recorded at the time of biopsy. Post biopsy protocol included vitals and urine void checked visually for haematuria. Logistic regression was used to investigate links between AVF, needle size, correcting for potential confounding variables.

RESULTS

46,5% were kidney transplants and 53,5% were native biopsies. Diagnostic material was obtained in 90,5% (142 grafts and 154 native). Forty-seven AVF's (14.37%) were identified with routine kidney Doppler mapping, 95% asymptomatic (n = 45), 28 in grafts (18.4%) and 17 natives (9.7%) (p-value 0.7). Both groups were comparable in terms of comorbidities, passes, cylinders or biopsy yield (p-value NS). 80% were <1 cm in size and 46.6% closed spontaneously in less than 30 days (range 3-151). Larger AVF's (1-2 cm) took a mean of 52 days to closure (range 13-151). Needle size was not statistically significant factor for AVF (p-value 0.71).

CONCLUSIONS

Contrary to historical data published, AVF's are a common complication post PRB that can be easily missed. Routine US Doppler mapping performed by trained staff is a cost-effective, non-invasive tool to diagnose and follow up AVF's, helping to assess management.

Transarterial Embolization of a Renal Artery Aneurysm Concomitant With Renal Arteriovenous Fistula

Congenital renal artery aneurysm is uncommon. Moreover, renal artery aneurysm concomitant with a congenital renal arteriovenous fistula is extremely rare. Transarterial embolization is the first-line treatment for these conditions. We report a case of a patient with congenital renal artery aneurysm concomitant with a congenital renal arteriovenous fistula of the upper polar left renal artery which was successfully treated by transarterial embolization with coil, glue, and Amplatzer vascular plug.

Incidence of A-V Fistulas after Renal Biopsy of Native and Transplanted Kidney - Two Centers Experience

AIM:

The aim of the study is to make a retrospective analysis of the incidence of AV fistulas after renal biopsy (RB) of native and transplanted kidney.

MATERIALS AND METHODS:

Five hundred and sixteen (516) RB were analyzed. One hundred twenty nine (129) were native kidneys RB performed in Clinic of Nephrology (CN), 190 were performed in Clinic of Nephrology and transplantation (CNT) and 197 were transplanted kidney biopsies from the same clinic. Biopsy technique type Gun with needle 14G, 16 and 18 G was used in CN, CNT used the same technique with needles 16G. Doppler ultrasound was made for A-V fistulas diagnosis.

RESULTS:

The A-V fistulas incidence was 0.8%. The frequency of A-V fistulas registered in CN was significantly higher than that registered in CNT (2.3% vs. 0.5%, p < 0.01). Biopsies performed by 14 G needles provide a higher percentage of A-V fistulas compared to those done by 16 G. (3.3% vs. 2.4%, p < 0.5). The frequency of the A-V fistulas in native and transplanted kidneys in CNT was similar (0.5% vs. 0.5%, p > 0.05).

CONCLUSION:

The A-V fistulas incidence is very low. The needle thickness is an important factor relevant to the risk of occurrence of A-V fistulas.

Aneurysmal dilatation associated with arteriovenous fistula in a transplanted kidney after renal biopsies

AVF is a known complication of renal biopsy in both native and transplanted kidneys. A 20-yr-old woman with bilateral hypoplastic kidneys due to branchio-oto-renal syndrome had received living-donor renal transplantation from her father at the age of 11. She had undergone allograft renal biopsies six times and all puncture sites were at the lower pole of her kidney from the first to the fifth biopsy. AVF with aneurysmal dilation (30 mm) had developed at the puncture site after the fifth biopsy. TAE was successfully performed with 11 platinum coils in the branch of the renal artery feeding the aneurysm. According to a review of the literature, the incidence of AVF is higher in transplanted kidneys than in native kidneys (7.5% vs. 2.1%) because transplanted kidneys, as single kidneys, are likely to be punctured repeatedly at the same site. When renal biopsy of a transplanted kidney is performed, previous biopsy puncture sites should be considered and the biopsy should be performed at a different site, if possible, to prevent the development of AVF.

ESPR uroradiology task force and ESUR Paediatric Work Group--Imaging recommendations in paediatric uroradiology, part VI: childhood renal biopsy and imaging of neonatal and infant genital tract. Minutes from the task force session at the annual ESPR Meeting 2012 in Athens on childhood renal biopsy and imaging neonatal genitalia

The European Society of Paediatric Radiology Uroradiology Task Force and the ESUR Paediatric Work Group jointly publish guidelines for paediatric urogenital imaging. Two yet unaddressed topics involving patient safety and imaging load are addressed in this paper: renal biopsy in childhood and imaging of the neonatal genital tract, particularly in girls. Based on our thorough review of literature and variable practice in multiple centers, procedural recommendations are proposed on how to perform renal biopsy in children and how to approach the genital tract in (female) neonates. These are statements by consensus due to lack of sufficient evidence-based data. The procedural recommendation on renal biopsy in childhood aims at improving patient safety and reducing the number of unsuccessful passes and/or biopsy-related complications. The recommendation for an imaging algorithm in the assessment of the neonatal genital tract focuses on the potential of ultrasonography to reduce the need for more invasive or radiating imaging, however, with additional fluoroscopy or MRI to be used in selected cases. Adherence to these recommendations will allow comparable data and evidence to be generated for future adaptation of imaging strategies in paediatric uroradiology.

Renal relevant radiology: imaging in kidney transplantation

Kidney transplantation can be associated with various complications that vary from vascular complications to urologic disorders to immunologic adverse effects. In evaluating the recipient with graft dysfunction, clinicians can choose among several imaging modalities, including ultrasonography, nuclear medicine studies, computed tomography, and magnetic resonance imaging. This review discusses the evaluation of the kidney transplant recipient using these imaging procedures, emphasizing the clinical diagnostic utility and role of each modality. A kidney biopsy is often required as a gold standard for diagnostic purposes. However, because of the inherent risks of a kidney biopsy, noninvasive imaging in diagnosing causes of graft dysfunction is a highly desired tool used and needed by the transplant community. Because the diagnostic accuracy varies depending on the time course and nature of the transplant-related complication, this review also addresses the advantages and limitations of each modality. The recent advances in kidney transplant imaging techniques and their clinical implications are also discussed.

Renal artery embolization

Renal artery embolization (RAE) is an effective minimally invasive alternative procedure for the treatment of a variety of conditions. Since the 1970s when RAE was first developed, technical advances and growing experience have expanded the indications to not only include treatment of conditions such as symptomatic hematuria and palliation for metastatic renal cancer, but also preoperative infarction of renal tumors, treatment of angiomyolipomas, vascular malformations, medical renal disease, and complications following renal transplantation. With the drastically improved morbidity associated with this technique in part due to the introduction of more precise embolic agents and smaller delivery catheters, RAE continues to gain popularity for various urologic conditions. The indications and techniques for renal artery embolization are reviewed in the following sections.

Imaging evaluation of kidney transplant recipients

Renal transplantation is nowadays accepted as the treatment of choice for patients with end-stage renal disease. However, despite progress in immunosuppression and surgical techniques, various complications still can occur. Complications vary from vascular disorders and urologic diseases to parenchymal and immunologically related complications. The clinician evaluating the recipient with graft dysfunction has the option of choosing among a variety of imaging modalities including ultrasonography, nuclear medicine, computed tomography, and magnetic resonance imaging to start or continue the diagnostic work-up. In this article, we discuss the evaluation of the kidney transplant recipient using these imaging procedures, emphasizing the clinical diagnostic utility and role of each modality.

Interventional management of renal transplant arteriovenous fistula

Percutaneous needle biopsy has become an indispensable tool for the evaluation and management of patients with renal allograft dysfunction. But this invasive procedure is not without risk. Vascular injury in the form of arteriovenous fistula, pseudoaneurysm, or arteriocalyceal fistula may result in symptoms that require percutaneous endovascular intervention. In this article, the occurrence, detection, and treatment of biopsy-related renal transplant injury are described.

Treatment of an extracapsular post-renal biopsy pseudoaneurysm with ultrasound-guided thrombin injection

Percutaneous renal biopsy is a convenient method to obtain allograft tissue for histologic evaluation. Vascular complications, such as arteriovenous (AV) fistula and pseudoaneurysm, following renal biopsy are well known, and they usually resolve without further intervention. When symptomatic, they should be treated. We present a patient on chronic anticoagulation who developed a pseudoaneurysm after percutaneous renal biopsy. Applying techniques learned in the management of femoral artery pseudoaneurysm, we treated our patient with ultrasound-guided thrombin injection.

Imaging of the renal donor and transplant recipient

Renal transplant remains the mainstay of the treatment of end-stage renal disease. With improvement in management strategies and the diverse imaging options, the yearly survival of recipients with functional kidneys has improved significantly. This improved survival is attributed to factors such as immunosuppressive therapy planning in recipients, human leukocyte antigen matching, surgeon experience, and recipient's age. Transplantation offers the closest thing to a normal state if the transplanted kidney can replace the failed kidneys. Living-donor kidney transplants are playing a vital role in bridging the gap between decreased supply of, and increased demand for, kidneys for transplant. Early detection and characterization of complications in the recipient are of immense clinical relevance, allowing timely intervention to prevent graft failure.

Course and relevance of arteriovenous fistulas after renal transplant biopsies

Arteriovenous fistulas (AVFs) after renal transplant biopsy are considered harmless. However, verification of the clinical course has not been thoroughly documented. We evaluated the data of our outpatient renal transplant biopsy program regarding the clinical course of AVFs after 2824 biopsies since 2000. We also reviewed all selective renal transplant embolizations. AVFs were the most frequent biopsy complications (8.3%). Seventy-seven percent of AVFs disappeared spontaneously. Renal function in patients with AVFs was not different compared to those without during 2 years of observation. There were no differences in AVFs comparing protocol or indication biopsies, needle size, the time after transplantation, the use of acetylic salicylic acid or serum-creatinine at biopsy. Living or younger donors were less likely to get postbiopsy AVFs. Ten embolizations were performed. Only one patient was from our outpatient biopsy program. Nine others were biopsied as inpatients in the course of complications during 6 weeks after transplant. Six of nine successfully embolized patients profited with improvement of renal function. Large AVFs occur most commonly shortly after transplantation in patients with poor graft function. There is no established test predicting which patient will benefit from embolization; however, Doppler-determined resistive index may help in this regard.

Renal vascular imaging: ultrasound and other modalities

Sonographic evaluation of the genitourinary system is a fast, safe, and effective means to detect renal disease. In conjunction with other modalities, Doppler can depict a variety of abnormalities. However, optimization of Doppler techniques and a solid understanding of Doppler threshold criteria are critical for success, whether in the native or transplanted kidney.

Sonographic evaluation of vascular injuries

OBJECTIVE

The purpose of this presentation is to highlight the color Doppler duplex sonographic features of procedure-related and blunt or penetrating trauma-related vascular injuries.

METHODS

Different kinds of vascular complications such as pseudoaneurysms, arteriovenous fistulas, dissection, and thrombosis are discussed. Cases of vascular injuries in the extremities, neck, and abdomen are presented to illustrate the spectrum of sonographic appearances.

RESULTS

Color Doppler duplex sonography is valuable in the diagnosis and monitoring of most vessel injuries and in the treatment of pseudoaneurysms. It is useful for flow analysis and for follow-up after treatment. However, because of limitations inherent to sonography, such as bones, air, casts, skin burns, and relatively slow performance of the test, magnetic resonance imaging, computed tomography, and angiography are necessary for further evaluation in selected cases.

CONCLUSIONS

Color Doppler duplex sonography is a widely available, noninvasive, and accurate technique for evaluating vascular injuries and should be the first-line imaging modality in most patients.

Renal arteriovenous aneurysm in a 4-year-old patient

We report a case of a symptomatic renal arteriovenous aneurysm in a 4-year-old pediatric patient. We were able to diagnose the lesion by means of a Doppler renal sonogram with color duplex interrogation. The diagnosis was confirmed by digital subtraction angiography. On the basis of the angiographic findings, the aneurysm was resected, and the renal arteriovenous fistula was repaired.

Pediatric applications of abdominal vascular Doppler: Part II

Ultrasound is a remarkably powerful and versatile modality for pediatric imaging, without requiring exposure to radiation or sedatives. By providing information on blood flow, Doppler sonography can reveal details about normal physiology and disease processes not discernable from gray-scale anatomic images alone. In part I, the basics of hemodynamics and effects on the Doppler waveform were discussed, along with clinical applications in hepatic disease. In part II, the application of Doppler in renal disease and in conditions affecting the deep abdominal vessels are discussed. The role of ultrasound contrast agents in pediatric Doppler imaging is briefly reviewed.

Emergency Doppler evaluation of the liver and kidneys

Doppler ultrasound is useful in the emergent evaluation of the liver and kidney transplant patient. Arterial stenosis, pseudoaneurysm, and venous thrombosis are treatable causes of allograft failure that can be detected easily with color and spectral Doppler. Doppler has a limited but important role in the emergent evaluation of the native liver and kidneys, usually involving prior biopsy or instrumentation.

Imaging in Renal Transplantation

Renal transplantation is the best treatment option for chronic renal failure, with marked improvement in social activity, work, and family life. In addition to these obvious improvements, it is an extremely cost-effective procedure when successful. Ultrasonography plays a major role in the imaging of these patients, and ultrasound (including color Doppler) is helpful to the transplant physician in detecting graft dysfunction and peritransplant collections, some of which may be drained under ultrasound guidance. It is also helpful in the diagnosis of chronic vascular complications including transplant artery stenosis and arteriovenous fistula. It has no specific application in the diagnosis of chronic rejection.

Imaging guided interventional procedures in paediatric uroradiology--a case based overview

OBJECTIVE

To describe the potential and application of interventional image guided procedures in the paediatric urinary tract.

PATIENTS AND METHODS

The different techniques are illustrated using case reports. The examples comprise established indications such as percutaneous nephrostomy for compromised kidneys in obstructive uropathy and infection, sonographic guided renal biopsy including monitoring or treatment of complications after biopsy, and evaluation and balloon dilatation of childhood renal artery stenosis. There are new applications such as treatment of stenosis in cutaneous ureterostomy or sonographically guided catheterism for deployment of therapeutic agents.

RESULTS

Generally, the procedures are safe and successful. However, complications may occur, and peri-/post-interventional monitoring is mandatory to insure early detection and adequate management. Sometimes additional treatment such as percutaneous embolisation of a symptomatic post biopsy arterio-venous fistula, or a second biopsy for recurrent disease may become necessary.

CONCLUSION

Imaging guided interventional procedures are performed successfully in a variety of diseases of the paediatric urinary tract. They can be considered a valuable additional modality throughout infancy and childhood.

Post-biopsy renal arteriovenous fistula

A 6-yr-old boy developed progressively severe hypertension, which was unresponsive to medications, 1 week after percutaneous biopsy of his renal transplant. Renal angiogram revealed an arteriovenous fistula (AVF) in the lower pole at the site of the biopsy. Case findings and resolution after embolization are described, and the current literature is briefly reviewed.

Ultrasound of renal transplantation

The most effective primary treatment of chronic renal failure is renal transplantation. A significant improvement in lifestyle and family life in conjunction with it being an extremely cost-effective procedure has resulted in an intense monitoring and imaging programme to help ensure a successful outcome. Ultrasound, both grey-scale and colour-flow Doppler, are useful monitoring techniques when interpreted in the clinical context, and in the delineation of peri-transplant collections, some of which can be drained under ultrasound guidance. After the early post-operative period it can also be utilized in the diagnosis of chronic vascular complications including transplant artery stenosis and arteriovenous fistula, although it is of limited use in the diagnosis of chronic rejection. This article will discuss the role of ultrasound in all its guises and how its efficacy in both the early transplant period in the monitoring of graft dysfunction and in the detection of the more chronic conditions including transplant artery stenosis and arteriovenous fistulae. A more limited role for ultrasound also exists in the long-term follow-up of patients and to aid the detection of complications including susceptibility to malignancy.

Endovascular treatment of arteriovenous fistulas complicating percutaneous renal biopsy in three paediatric cases

DESIGN

We evaluated the incidence and history of arteriovenous fistula (AVF) after kidney biopsy and assessed the use of superselective embolization for treatment.

OBSERVATIONS

During the last 10 years, 896 kidney biopsies (age range of the patients: 1 month-18.6 years) have been performed in our institution under real-time ultrasonographic guidance with a 14 gauge cutting biopsy needle, and 32 of the patients had renal allografts (3.4%). We observed three cases of AVF (two in allograft kidneys, one in a native kidney) among all biopsies (0.34%), and the incidence of developing AVF after renal allograft biopsy was 6.3%. All three patients with AVF were symptomatic, and intravascular therapy was indicated.

INTERVENTIONS

An angiographic study combined with endovascular treatment of the intrarenal AVF and pseudoaneurysm was performed in all three patients. Embolization was performed with bucrylate and lipiodol in two patients and with micro-coils in one. After successful embolization, all three patients became asymptomatic (in two renal bleeding stopped, in one patient with severe uncontrollable hypertension blood pressure returned to normal limits). No complications were observed secondary to the embolization procedure.

CONCLUSION

The technique of superselective embolization using a coaxial catheter is an effective and safe method in the treatment of post-biopsy AVFs and pseudoaneurysm.

A rare complication of renal biopsy in a child with membranoproliferative glomerulonephritis

Percutaneous renal biopsy is essential for the definitive diagnosis of chronic glomerulonephritis. Large arteriovenous fistula (AVF) which is a rare complication of native renal biopsy is generally diagnosed in the first weeks after the procedure. We present a childhood membranoproliferative glomerulonephritis case with an enormous AVF presenting with severe hypertension 15 months after the biopsy that was successfully embolized. In conclusion, AVF must be considered in children having chronic glomerulonephritides even if hypertension appears late after the renal biopsy.

Transcatheter embolization of biopsy-related vascular injury in the transplant kidney: immediate and long-term outcome

PURPOSE

To assess the effect of transcatheter embolization for treatment of biopsy-related vascular injury in renal allografts, specifically evaluating technical success, clinical benefit, and long-term effect on renal function.

MATERIALS AND METHODS

A retrospective review was performed of all postbiopsy renal allograft vascular injuries referred for embolization during a 113-month period. The likelihood of a prolonged detrimental effect on allograft function was estimated from observed variation in serum creatinine levels before and after the procedure.

RESULTS

Embolic therapy with use of metallic coils and superselective technique was performed in 21 renal transplant patients. Technical success was achieved in 95% of cases. There were no serious complications. Eradication of the clinical sign or symptom prompting referral was seen in 15 of 17 (88%) patients. Eleven of 19 (58%) patients analyzed demonstrated no evidence of a long-term detrimental effect on allograft function. A detrimental effect was possibly present in six of 19 (32%) patients, and probable in only two of 19 (10%) patients.

CONCLUSIONS

Transcatheter embolization can be an appropriate and effective therapeutic choice for biopsy-related renal allograft vascular injury.

Colour Doppler ultrasound in renal transplant artery stenosis: which Doppler index?

A prospective study comparing colour Doppler ultrasound (US) with the 'gold standard' of intra-arterial digital subtraction angiography in the evaluation of renal transplant artery stenosis was performed. Both the intrarenal vessels and the transplant renal artery were examined by Doppler US. Diagnostic arteriography was performed only if, on Doppler, the peak systolic velocity in the transplant renal artery exceeded 1.5 ms-1. Of 109 patients, the transplant artery could not be visualized using colour Doppler US in three, and these were omitted from statistical analysis. Of the remaining 106 patients, 31 had a peak systolic velocity greater than 1.5 ms-1 in the transplant renal artery and were referred for DSA. Of the multiple renal Doppler indices recorded, the peak systolic velocity in the transplant artery was the best discriminating measurement for the detection of renal artery stenosis. A peak systolic velocity of > or = 2.5 ms-1 in the transplant renal artery had a sensitivity of 100% and a specificity of 95% for the detection of renal artery stenosis ( > 50% diameter reduction). Although a significant difference in Pulsatility Index, Resistive Index, Acceleration Index and Acceleration Time was recorded from the intrarenal vessels in the angiographically normal and stenosed groups with Doppler, these measurements were less useful as discriminating diagnostic tests. In conclusion, the peak systolic velocity in the transplant renal artery is the most sensitive Doppler criterion for renal artery stenosis and is sensitive and specific enough to be used as a screening test. The intrarenal acceleration time and index should not be used in isolation.