Percutaneous needle biopsy of the renal allograft using the automated needle system: evaluation of 87 procedures

Arteriovenous fistulas after ultrasound-guided needle biopsy of kidney allografts and treatment outcomes after transcatheter embolization: A single-center experience in Japan

BACKGROUND

Arteriovenous fistula (AVF) is one of the vascular complications after allograft biopsy, and their reported incidence rates range widely. Transcatheter embolization (TE) is a common AVF treatment in kidney allografts. However, information on AVF incidence and features and TE outcomes in Japanese kidney transplant (KT) recipients is lacking.

METHODS

This study investigated 270 protocol or clinically indicated kidney allograft biopsies in 129 KT recipients during 2010-2016 at a single-center using standardized methods (16-gauge needle and ultrasound guidance). We recorded the incidence and clinical features of AVF using currently recommended standardized methods of allograft biopsy and TE outcomes regarding allograft function up to 12 months after the procedure in Japanese KT recipients.

RESULTS

AVF incidence was 2.6% (seven cases). The time from biopsy to AVF diagnosis was 7 (median, interquartile range: 5-117, range: 1-318) days. The time from biopsy to AVF diagnosis was significantly shorter in symptomatic cases (gross hematuria) than in asymptomatic cases (median 6 vs. 117 days, p = 0.034). Symptomatic patients underwent TE within a shorter time (0-6 days) than asymptomatic patients (25-104 days). There were no complications, and allograft function was stable up to 12 months after TE despite using contrast media and partial renal infarction.

CONCLUSIONS

AVF does occur in certain probabilities. AVF formation can occur without apparent bleeding and exist for a long time after allograft biopsy. TE is a safe and immediate treatment for AVF in kidney allograft.

Effects of Aspirin Therapy on Ultrasound-Guided Renal Allograft Biopsy Bleeding Complications

PURPOSE

To determine if patient aspirin exposure and timing affect bleeding risk after renal allograft biopsy.

MATERIALS AND METHODS

Review of 6,700 renal allograft biopsies (in 2,362 unique patients) was performed. Median patient age was 53.0 years [interquartile range 43.0, 62.0]; 56.2% of patients were male. Of biopsies, 4,706 (70.2%) were performed in patients with no aspirin exposure within 10 days of biopsy; 664 (9.9%), were performed within 8-10 days of aspirin exposure; 855 (12.8%), within 4-7 days; and 475 (7.1%), within 0-3 days. Follow-up to 3 months after the procedure was completed in all patients. Biopsies were categorized as protocol or indication; 19.7% were indication biopsies. Bleeding complications were graded based on SIR criteria. Logistic regression models examined the association between aspirin use and bleeding events.

RESULTS

Rate [95% confidence interval] of major bleeding complications was 0.24% [0.14, 0.39], and rate of any bleeding complication was 0.66% [0.46, 0.90]. Bleeding events were significantly associated with patients undergoing indication biopsies compared with protocol biopsies (odds ratio [OR] 2.27, P = .012). Patient factors associated with major bleeding complications in multivariate models included estimated glomerular filtration rate (OR 0.61, P = .016) and platelet count (OR 0.64, P = .033). Aspirin use was not significantly associated with increased risk of bleeding complication except for use of 325 mg of aspirin within 3 days of biopsy (any complication OR 3.87 [1.12, 13.4], P = .032; major complication OR 6.30 [1.27, 31.3], P = .024).

CONCLUSIONS

Renal allograft biopsy bleeding complications are very rare, particularly for protocol biopsies. Use of 325 mg of aspirin within 3 days of renal allograft biopsy was associated with increased bleeding complications.

Pediatric urologic interventional radiology

Interventional radiologists are playing an increasingly important role in pediatric urologic intervention, working closely with the pediatric urologist. Interventional radiologists are frequently asked to establish percutaneous access to the renal collecting system prior to nephrolithotomy. Additionally, procedures such as percutaneous nephrostomy, ureteral stent placement and exchange, and renal parenchymal biopsy are frequently encountered requests. This article will review these common procedures and highlight techniques and pathology that are unique to the pediatric population.

Comparison of palpation-guided and ultrasound-guided biopsies in transplanted kidneys

Biopsy is the gold standard for the diagnosis of conditions affecting the function of renal allografts. Obtaining representative tissue in biopsies is critical but these procedures are associated with up to 9% of complications and 20% of inadequate material. Although ultrasound guidance allows perfect control of depth and location of the graft, there is controversy regarding the cost-benefit of its use and reports of unsuitable material in ultrasound-guided biopsies are still high.

PURPOSE

To compare ultrasound with the palpation method to guide biopsies in order to see if there is any difference between both methods and which one is better.

PATIENTS AND METHODS

The casuistic consisted of 82 renal transplant patients (32 female and 50 male patients, age ranging between 5 and 64 yr; m=31.2 yr) randomized into two groups: GI, palpation-guided; GII, ultrasound-guided. Fifty-six biopsies were performed in GI and 66 in GII.

RESULTS

Number of glomeruli, arcuate, and interlobar arteries and arterioles were compared in the two groups and were 503 (m=10) vs. 801 (m=12.9), 24 (m=0.5) vs. 38 (m=0.6), 104 (m=2.1) vs. 154 (m=2.5), and 174 (m=3.5) vs. 264 (4.3), respectively (p<0.05). Inadequate material for analysis in GI and GII was 7.1 and 7.6%, respectively (p=0.72).

CONCLUSIONS

Although ultrasound guidance improves the number of glomeruli, arcuate, and interlobar arteries, as well as arterioles, compared with palpation-guided biopsies, there is no difference in the rate of adequate material between the two methods.

Histological outcome of acute cellular rejection in kidney transplantation after treatment with methylprednisolone

BACKGROUND

Several studies comparing the response of acute cellular rejection (ACR) episodes to different corticosteroid regimens have been conducted. However, in most of them, the histological evaluation of the infiltrate and its correlation with clinical response was not studied. The clinical and histological outcomes of 37 episodes of ACR treated with methylprednisolone (MP) were studied, with the aim to determine how long the infiltrate takes to be cleared after therapy.

METHODS

A total of 37 patients with biopsy-proven ACR were treated with 8 or 16 mg of MP/kg/day. Allograft biopsies were repeated at 5 and 10 days after the end of corticotherapy. Clinical and histological outcomes were compared.

RESULTS

Six patients were excluded; 15 (48.4%) patients responded to therapy; the mean serum creatinine of these patients reached normal levels in the 2 weeks that followed treatment. Nine patients (60%) of this group had signs of ACR on biopsies done 5 days after corticotherapy, and four (26.7%) maintained them on the 10th day. Among 16 patients with no clinical response, none reached normal serum creatinine levels; 15 (93.7%) had signs of rejection 5 days after treatment and maintained them on the 10th day. Histological signs of ACR disappeared in 73.3% of patients with clinical response 10 days after therapy, but in only 6.3% of patients with no response (P=0.001).

CONCLUSIONS

Biopsies performed 5 days after treatment show a high incidence of features of ACR; such features take on average 10 days to disappear in nearly 75% of cases with successful therapy with MP.

Kidney transplantation: the use of living donors with renal artery lesions

PURPOSE

A shortage of organs for transplantation has forced surgeons to optimize the use of marginal organs, such as kidneys with arterial disease. We present a retrospective study of the outcome of donors with renal artery disease and recipients of kidneys from living related and unrelated donors.

MATERIALS AND METHODS

Kidneys with vascular abnormalities from healthy living donors were grafted into 11 recipients. These kidney transplants comprised 1.8% of those performed at our institution. The vascular abnormalities were aneurysms in 3 cases, atherosclerotic lesions in 4 and fibromuscular dysplasia in 4. After nephrectomy all abnormalities were corrected under hypothermic conditions during bench surgery except in 3 cases of ostial atherosclerotic plaque, which was left in the donors. The renal artery was anastomosed to the external iliac artery in 5 cases and to the internal iliac artery in 6. The ureter was reimplanted using an extravesical technique.

RESULTS

All patients had immediate diuresis and no delayed post-transplant graft dysfunction was observed. One patient died of an unrelated cause and 3 had post-transplant graft function loss due to acute vasculopathy in 1, post-diarrhea with acute arterial thrombosis in 1 and recurrence of the hemolytic-uremic syndrome in 1. All remaining patients are well with median serum creatinine of 1.4 mg./dl. (normal 0.4 to 1.4). All donors are well and normotensive with normal renal function.

CONCLUSIONS

The use of kidneys with arterial disease from living donors with unilateral disease is safe. Complete informed consent regarding the risks and benefits by donor and recipient is mandatory.

Diagnostic contribution of renal allograft biopsies at various intervals after transplantation

Renal allograft biopsy is the accepted gold standard for investigating episodes of graft dysfunction in the early posttransplant period. The situation is less clear in late transplant biopsies. Later renal biopsies performed for graft dysfunction or as part of a routine investigative protocol have not been subjected to detailed critical evaluation. Two hundred sixty-three consecutive renal allograft biopsies in a single center were evaluated. They were arbitrarily divided into three groups based on interval after transplantation: group 1, up to 3 months (n=117); group 2, 4-12 months (n=60); and group 3, greater than 12 months after transplantation (n=86). There were no significant differences in demographic factors among the groups. The mean interval after transplantation was 0.8+/-0.1 months in group 1, 6.1+/-0.3 months in group 2, and 40.1+/-3.4 months in group 3. There were six principal diagnostic categories: acute rejection (AR), chronic rejection (CR), cyclosporine (CsA) nephrotoxicity, acute tubular necrosis (ATN), normal, and others. A statistically significant decrease in the frequency of AR (P<0.001) was seen in group 3 (3%) compared with groups 1 (43%) and 2 (37%). In contrast, the frequency of CR was significantly higher (P<0.001) in group 3 (71%) compared with groups 1 (0) and 2 (10%). ATN was seen almost exclusively in group 1. All but one of the 37 patients with ATN were in this group. CsA nephrotoxicity remained an important cause of graft dysfunction in all three groups, with no significant difference in incidence among the three groups. The differences between groups with other histological types were not significant. Patient management was changed based on the biopsy report in 84 patients in group 1 (72%), 45 patients in group 2 (75%), and only 16 patients in group 3 (19%) (P<0.001). In only seven patients in group 3 did the change in management result in a significant change in serum creatinine. All of these seven patients had CsA nephrotoxicity on biopsy and also had a significantly higher level of CsA compared with those with AR or CR. Thus, the diagnosis might have been possible without the need for biopsy. We conclude that late renal allograft biopsies are only rarely helpful in patient management and as such should be an investigation of last resort.

Outcomes of percutaneous kidney biopsy, including those of solitary native kidneys

A solitary native kidney is generally considered to be an absolute contraindication to percutaneous biopsy. However, technical advances, such as real-time ultrasound guidance and automated core biopsy systems, provide an excellent safety profile with an extremely low risk of catastrophic complications and have caused some investigators to call for a reassessment of this contraindication. The overall results at our institution are reported. Of 544 consecutive native and allograft kidney biopsies conducted over 2.5 years, 482 were performed with an automated core biopsy system and 281 also used real-time ultrasound guidance. The overall complication rate was 5.3%. Transient gross hematuria was seen in 4.4% and hematoma was seen in 1.5%; no patient experienced loss of kidney function and there were no deaths. We recently have begun to perform percutaneous biopsy of solitary native kidneys in carefully selected patients. To date, nine such procedures have been attempted, with success in eight cases. One patient had transient gross hematuria; no other complications were noted. This encouraging preliminary experience suggests that otherwise uncomplicated adult patients with a solitary kidney might be considered for percutaneous biopsy. It now seems appropriate to prospectively evaluate percutaneous biopsy of solitary kidneys in a larger cohort of unselected patients.