Percutaneous needle biopsy of the renal allograft. A clinical safety evaluation of 1129 biopsies

Effects of Aspirin on Kidney Biopsy Bleeding Complications: A Systematic Review and Meta-Analysis (PROSPERO 2021 CRD42021261005)

Postprocedural bleeding is the main complication of percutaneous kidney biopsy (PKB). Therefore, aspirin is routinely withheld in patients undergoing PKB to reduce the bleeding risk. The authors aimed to examine the association between aspirin use and bleeding during PKB. This systematic review and meta-analysis was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The article search was performed on MEDLINE and Scopus using queries specific to each database. Article inclusion was limited to primary studies. The meta-analysis compared the risk of major bleeding events between the aspirin-exposed versus nonexposed group. Pooled effect estimate was examined using random effects presented as odds ratio with 95% confidence intervals. Heterogeneity was assessed through Cochrane I 2 test statistics. Sensitivity and subgroup analyses were also performed according to kidney type. Ten studies were included in the review and four studies were included in the meta-analysis, reviewing a total of 34,067 PKBs. Definitions for significant aspirin exposure were inconsistent between studies, limiting comparisons. Studies with broader definitions for aspirin exposure mostly showed no correlation between aspirin use and postbiopsy bleeding. Studies with strict definitions for aspirin exposure found an increased risk of hemorrhagic events in the aspirin-exposed group. No significant differences were found between the aspirin-exposed and comparison groups regarding major bleeding events (odds ratio 1.72; 95% confidence interval 0.50 to 5.89, I 2 =84%). High-quality evidence on the effect of aspirin on the bleeding risk is limited. Our meta-analysis did not show a significantly increased risk of major bleeding complications in aspirin-exposed patients. Further studies are needed to define a more comprehensive approach for clinical practice.

Protocol Biopsy After Kidney Transplant: Clinical Application and Efficacy to Detect Allograft Rejection

Background Kidney transplant rejection is a major cause of graft dysfunction and failure. In recent years, there has been increased interest in renal allograft protocol biopsies to allow earlier detection of acute or chronic graft dysfunction or rejection to improve long-term graft survival and reduce graft failure. This study aimed to determine if renal allograft protocol biopsies performed within the first 12 months after transplantation help detect subclinical graft dysfunction or rejection. Methods We performed a retrospective analysis utilizing SUNY Upstate University Hospital data from January 2016 to March 2022 to assess transplant outcomes and biopsies. The study population was divided into two subgroups: non-protocol biopsies and protocol biopsies within the 12 months post-transplant. Results A total of 332 patients met our inclusion criteria and were included in the study. Patients were divided into two subgroups: 135 patients (40.6%) in the protocol biopsy group and 197 patients (59.4%) with non-protocol indication biopsies during the first year after the transplant. The overall number of rejection episodes reported was eight episodes (4.6%) in the protocol biopsy group and 56 episodes (18.3%) in the non-protocol indication biopsy group, which was significantly higher in the non-protocol biopsy group (P=0.001). Antibody-mediated rejection (ABMR) and T-cell-mediated rejection (TCMR) diagnoses were significantly higher in the non-protocol biopsy group (P=0.03 and P=0.03, respectively). We also mentioned a trend in terms of mixed antibody-mediated rejection and T-cell-mediated rejection diagnosis (P=0.07). One year after the rejection, the mean glomerular filtration rate (GFR) was 56.78 mL/min/1.73m² in the protocol biopsy group and 49.14 mL/min/1.73m² in the non-protocol indication biopsy group, and there was no significant difference anymore (P=0.11). The patient survival rate was not significantly higher in the protocol biopsy group compared to the non-protocol indication biopsy group (P=0.42). Conclusion This study suggests that performing protocol biopsies does not significantly benefit rejection rates, graft survival, or renal function within the first 12 months post-transplant. Given these results and the small but non-zero risk of complications associated with protocol biopsies, they should be reserved for those patients at high risk of rejection. It may be more feasible and beneficial to utilize less invasive tests, such as DSA and dd-cfDNA testing, for early diagnosis of a rejection episode.

Complications of Percutaneous Kidney Allograft Biopsy: Systematic Review and Meta-analysis

BACKGROUND

Kidney biopsy is important to guide the management of allograft dysfunction but has a risk of complications. This review aimed to determine the incidence and risk factors of complications after kidney allograft biopsy.

METHODS

This is a systematic review and meta-analysis of randomized controlled trials, cohort studies, or case-control studies indexed on PubMed, Embase, Cochrane Central Register of Controlled Trials, World Health Organization International Clinical Trials Registry, and ClinicalTrials.gov, limited to the English language, from January 2000 to December 2020, including adult and pediatric kidney allograft biopsies. Primary outcomes were gross hematuria, bleeding requiring transfusion, and major complications (requiring interventions such as blood transfusion or surgical or radiological interventions).

RESULTS

The review included 72 studies (40 082 biopsies). The quality of included studies was suboptimal. Pooled rates of gross hematuria, bleeding requiring transfusion, and major complications were 3.18% [95% confidence interval (95% CI), 2.31-4.19], 0.31% (95% CI, 0.15-0.52) and 0.89% (95% CI, 0.61-1.22), respectively. Gross hematuria rates were lower in high-income compared with middle-income countries (2.59% versus 6.44%, P < 0.01) and biopsies performed by radiology as compared with nephrology departments (1.25% versus 3.71%, P < 0.01). Blood transfusion rates were lower in pediatrics than adults (0.0% versus 0.65%, P < 0.01). Major complications were lower in biopsies performed by specialists as compared with trainees (0.02% versus 3.64%, P < 0.01). Graft loss and mortality were extremely rare. Limitations included missing data, few randomized controlled trials, and possible publication bias.

CONCLUSIONS

The risk of complications after kidney allograft biopsy was low. Given the low quality of included studies, risk factors for complications should be further examined in future studies.

Risk factors for biopsy complications in initial versus subsequent biopsies in native and transplant kidneys

BACKGROUND

Few studies exist about risk factors for complications in subsequent biopsies.

PURPOSE

To explore risk factors for complications in initial versus subsequent biopsies in native and transplant kidneys, which may predict biopsy complications.

MATERIAL AND METHODS

In a multicenter study, 2830 native kidney biopsies (4.3% subsequent) were analyzed for major complications (1251 of these were also analyzed for minor) and 667 transplant kidney biopsies (29% subsequent) were analyzed for major and minor complications. No death or nephrectomy were described. Fisher's exact test, Student's t-test, chi-square analyses, and univariate and multiple binary logistic regression analyses were employed; P < 0.05 was considered significant.

RESULTS

In initial native kidney biopsies, the frequency of major complications was higher in women compared to men (odds ratio 1.6, 95% confidence interval 1.1-2.2), in younger patients (50 vs. 54 years, P = 0.007), and in patients with lower weight (78 vs. 82 kg, P = 0.005). In subsequent native kidney biopsies, patients with major complications had a higher systolic blood pressure (145 vs. 132 mmHg, P = 0.03). In initial transplant kidney biopsies, biopsies with major complications had less glomeruli in the biopsy (17 vs. 24, P = 0.046). In subsequent transplant kidney biopsies, patients with major complications had a higher mean arterial pressure (112 vs. 98 mmHg, P = 0.002). In subsequent native kidney biopsies, there was a higher number of SLE-nephritis (12% vs. 4.6%, P = 0.001) compared to initial biopsies.

CONCLUSION

The different types of risk factors for complications in initial versus subsequent renal biopsies could be important for the clinicians to improve patients' safety.

Protocol Biopsies on de novo Renal-Transplants at 3 Months after Surgery: Impact on 5-Year Transplant Survival

Background: In many centers, a protocol kidney biopsy (PKB) is performed at 3 months post-transplantation (M3), without a demonstrated benefit on death-censored graft survival (DCGS). In this study, we compared DCGS between kidney transplant recipients undergoing a PKB or without such biopsy while accounting for the obvious indication bias. Methods: In this retrospective, single-center study conducted between 2007 and 2013, we compared DCGS with respect to the availability and features of a PKB. We built a propensity score (PS) to account for PKB indication likelihood and adjusted the DCGS analysis on PKB availability and the PS. Results: A total of 615 patients were included: 333 had a PKB, 282 did not. In bivariate Kaplan–Meier survival analysis, adjusting for the availability of a PKB and for the PS, a PKB was associated with a better 5-year DCGS independently of the PS (p < 0.001). Among the PKB+ patients, 87 recipients (26%) had IF/TA > 0. Patients with an IF/TA score of 3 had the worst survival. A total of 144 patients (44%) showed cv lesions. Patients with cv2 and cv3 lesions had the worst 5-year DCGS. Conclusions: A M3 PKB was associated with improved graft survival independently of potential confounders. These results could be explained by the early treatment of subclinical immunological events. It could be due to better management of the immunosuppressive regimen.

A new lateral flow assay to detect sIL-2R during T-cell mediated rejection after kidney transplantation

Kidney is the most frequently transplanted among all solid organs worldwide. Kidney transplant recipients (KTRs) undergo regular follow-up examinations for the early detection of acute rejections. The gold standard for proving a T-cell mediated rejection (TCMR) is a biopsy of the renal graft often occurring as indication biopsy, in parallel to an increased serum creatinine that may indicate deterioration of renal transplant function. The goal of the current work was to establish a lateral flow assay (LFA) for diagnosing acute TCMR to avoid harmful, invasive biopsies. Soluble interleukin-2 (IL-2) receptor (sIl-2R) is a potential biomarker representing the α-subunit of the IL-2 receptor produced by activated T-cells, e.g., after allogen contact. To explore the diagnostic potential of sIL-2R as a biomarker for TCMR and borderline TCMR, plasma and urine samples were collected from three independent KTR cohorts with various distinct histopathological diagnostic findings according to BANFF (containing 112 rsp. 71 rsp. 61 KTRs). Samples were analyzed by a Luminex-based multiplex technique and cut off-ranges were determined. An LFA was established with two specific sIL-2R-antibodies immobilized on a nitrocellulose membrane. A significant association between TCMR, borderline TCMR and sIL-2R in plasma and between TCMR and sIL-2R in urine of KTRs was confirmed using the Mann-Whitney U test. The LFA was tested with sIL-2R-spiked buffer samples establishing a detection limit of 25 pM. The performance of the new LFA was confirmed by analyzing urine samples of the 2^nd and 3^rd patient cohort with 35 KTRs with biopsy proven TCMRs, 3 KTRs diagnosed with borderline TCMR, 1 mixed AMR/TCMR rsp. AMR/borderline TCMR and 13 control patients with a rejection-free kidney graft proven by protocol biopsies. The new point-of-care assay showed a specificity of 84.6% and sensitivity of 87.5%, and a superior estimated glomerular filtration rate (eGFR) at the time point of biopsy (specificity 30.8%, sensitivity 85%).

Renal transplant biopsy complications: assessment of risk factors and potential of desmopressin to decrease risk of hemorrhage

BACKGROUND

Renal transplant biopsies are essential in nephrology; however, they are invasive and complications can occur.

PURPOSE

To explore the risk of transplant kidney biopsy (TxB) complications in relation to possible preventive effects of desmopressin prophylaxis.

MATERIAL AND METHODS

A total of 515 consecutive TxB (375 patients, median age 53 years) were analyzed. In 252 TxB, the Resistive Index (RI) was measured right before the biopsy. A total of 282 patients had serum creatinine >150 µmol/L. In one of the six hospitals 39/282 patients consecutively received desmopressin (dose 0.3 µg/kg subcutaneously) as prophylaxis within 1 h before the biopsy. Fisher's exact and χ² test were used (odds ratio [OR], 95% confidence interval [CI]). Univariate and multiple binary logistic regression analyses were performed. A two-sided P value <0.05 was considered significant.

RESULTS

RI ≥ 0.8 was a risk factor for major TxB complications (OR 4.2, 95% CI 1.13-15.76). The risk for minor complications decreased with mean arterial blood pressure (MAP) (97.9 vs. 89.5 mmHg, OR 0.97, 95% CI 0.95-0.997). In a multiple regression analysis for overall biopsy complications, the risk remained increased for patients with RI ≥ 0.8 (OR 4.45, 95% CI 1.32-15.04). No patients (0/39) with desmopressin prophylaxis had a major complication versus 8/243 in the other group. In patients with serum creatinine >150 µmol/L, those with a higher MAP had more overall TxB complications (104.5 vs. 98.2 mmHg, OR 1.05, 95% CI 1.004-1.1).

CONCLUSION

RI ≥ 0.8 was a risk factor for major and overall complications and a lower MAP for minor biopsy complications. Desmopressin prophylaxis showed yet no verified benefit as prophylaxis in TxB.

Plasma Soluble CD146 as a Potential Diagnostic Marker of Acute Rejection in Kidney Transplantation

Previous studies have implicated the role of CD146 and its soluble form (sCD146) in the pathogenesis of inflammatory diseases. However, the association between CD146 and acute rejection in kidney transplant patients remains unexplored. In this study, fifty-six patients with biopsy-proved rejection or non-rejection and 11 stable allograft function patients were retrospectively analyzed. Soluble CD146 in plasma was detected in peripheral blood by enzyme linked immunosorbent assay (ELISA), and local CD146 expression in graft biopsy was detected by immunohistochemistry. We found that plasma soluble CD146 in acute rejection recipients was significantly higher than in stable patients without rejection, and the biopsy CD146 staining in the rejection group was higher than that of the non-rejection group. Multivariate analysis demonstrated soluble CD146 as an independent risk factor of acute rejection. The area under the receiver operating characteristic curve (AUC) of sCD146 for AR diagnosis was 0.895, and the optimal cut-off value was 75.64 ng/ml, with a sensitivity of 87.8% and a specificity of 80.8%, which was better than eGFR alone (P = 0.02496). Immunohistochemistry showed CD146 expression in glomeruli was positively correlated with the Banff-g score, and its expression in tubules also had a positive relationship with the Banff-t score. Therefore, soluble CD146 may be a potential biomarker of acute rejection. Increased CD146 expression in the endothelial or tubular epithelial cells may imply that endothelial/epithelial dysfunction is involved in the pathogenesis of immune injury.

Insights into the Role of Renal Biopsy in Patients with T2DM: A Literature Review of Global Renal Biopsy Results

INTRODUCTION

Renal biopsy performed in patients with type 2 diabetes mellitus (T2DM) for atypical or suspected diabetic kidney disease (DKD) reveals one of three possibilities: diabetic nephropathy (DN, pathological diagnosis of DKD), nondiabetic kidney disease (NDKD) and DN plus NDKD (mixed form). NDKD (including the mixed form) is increasingly being recognized worldwide. With the emerging concept of DKD and the complexity of routine application of renal biopsy, the identification of "clinical indicators" to differentiate DKD from NDKD has been an area of active research.

METHODS

The PubMed database was searched for relevant articles mainly according to the keyword search method. We reviewed prevalence of the three types of DKD and different pathological lesions of NDKD. We also reviewed the clinical indicators used to identify DKD and NDKD.

RESULTS

The literature search identified 40 studies (5304 data) worldwide between 1977 and 2019 that looked at global renal biopsy and pathological NDKD lesions. The overall prevalence rate of DN, NDKD and DN plus NDKD is reported to be 41.3, 40.6 and 18.1%, respectively. In Asia, Africa (specifically Morocco and Tunisia) and Europe, the most common isolated NDKD pathological type is membranous nephropathy, representing 24.1, 15.1 and 22.6% of cases, respectively. In contrast, focal segmental glomerulosclerosis is reported to be the primary pathological type in North America (specifically the USA) and Oceania (specifically New Zealand), representing 22% and 63.9% of cases, respectively. Tubulointerstitial disease accounts for a high rate in the mixed group (21.7%), with acute interstitial nephritis being the most prevalent (9.3%), followed by acute tubular necrosis (9.0%). Regarding clinical indicators to differentiate DKD from NDKD, a total of 14 indicators were identified included in 42 studies. Among these, the most commonly studied indicators included diabetic retinopathy, duration of diabetes, proteinuria and hematuria. Regrettably, indicators with high sensitivity and specificity have not yet been identified.

CONCLUSION

To date, renal biopsy is still the gold standard to diagnose diabetes complicated with renal disease, especially when T2DM patients present atypical DKD symptoms (e.g. absence of diabetic retinopathy, shorter duration of diabetes, microscopic hematuria, sub-nephrotic range proteinuria, lower glycated hemoglobin, lower fasting blood glucose). We conclude that renal biopsy as early as possible is of great significance to enable personalized treatment to T2DM patients.

Urinary Biomarkers α-GST and π-GST for Evaluation and Monitoring in Living and Deceased Donor Kidney Grafts

The aim of this study was to analyze the value of urine α- and π-GST in monitoring and predicting kidney graft function following transplantation. In addition, urine samples from corresponding organ donors was analyzed and compared with graft function after organ donation from brain-dead and living donors. Urine samples from brain-dead (n = 30) and living related (n = 50) donors and their corresponding recipients were analyzed before and after kidney transplantation. Urine α- and π-GST values were measured. Kidney recipients were grouped into patients with acute graft rejection (AGR), calcineurin inhibitor toxicity (CNI), and delayed graft function (DGF), and compared to those with unimpaired graft function. Urinary π-GST revealed significant differences in deceased kidney donor recipients with episodes of AGR or DGF at day one after transplantation (p = 0.0023 and p = 0.036, respectively). High π-GST values at postoperative day 1 (cutoff: >21.4 ng/mg urine creatinine (uCrea) or >18.3 ng/mg uCrea for AGR or DGF, respectively) distinguished between rejection and no rejection (sensitivity, 100%; specificity, 66.6%) as well as between DGF and normal-functioning grafts (sensitivity, 100%; specificity, 62.6%). In living donor recipients, urine levels of α- and π-GST were about 10 times lower than in deceased donor recipients. In deceased donors with impaired graft function in corresponding recipients, urinary α- and π-GST were elevated. α-GST values >33.97 ng/mg uCrea were indicative of AGR with a sensitivity and specificity of 77.7% and 100%, respectively. In deceased donor kidney transplantation, evaluation of urinary α- and π-GST seems to predict different events that deteriorate graft function. To elucidate the potential advantages of such biomarkers, further analysis is warranted.

[Renal transplantation: Procedure and early follow-up]

More than fifty years after the success of the two first renal transplantations in Boston and in Necker hospital in Paris, renal transplantation became the treatment of choice of end stage renal failure, because it improves not only the quality of life of the patients but also their long-term survival. In France, more than 3,700 kidney transplantations are performed every year and more than 40,000 patients are living with a functioning kidney allograft. This treatment of end stage renal disease requires a fine-tuned pre-transplant evaluation and a multidisciplinary post-transplant care in order to prevent, to detect and to treat comorbidities and complications of immunosuppression. The ambition of this manuscript is not to describe in an exhaustive way all the aspects of renal transplantation but starting from the experience of a team, recently published data, and national and international guidelines, to try to provide a synthetic and chronological view of the early post-transplant monitoring.

Urinary CXCL10 Chemokine Is Associated With Alloimmune and Virus Compartment-Specific Renal Allograft Inflammation

BACKGROUND

Urinary CXC chemokine ligand 10 (CXCL10) is a promising biomarker for subclinical tubulointerstitial inflammation, but limited data exist regarding its correlation with (micro)vascular inflammation. Furthermore, no study has evaluated whether concomitant serum CXCL10 improves the discrimination for (micro)vascular inflammation.

METHODS

We investigated whether serum/urinary CXCL10 reflect subclinical inflammation within different renal compartments. Patients (n = 107) with 107 surveillance biopsies were classified as: normal histology (n = 47), normal histology with polyomavirus BK (BKV) or cytomegalovirus (CMV) viremia (n = 17), moderate-severe tubulointerstitial inflammation (tubulitis ≥2, n = 18), pure microvascular inflammation (n = 15), and isolated v lesions (n = 10). Serum and urinary CXCL10 Enzyme-linked Immunosorbent Assay was performed. An independent validation set was evaluated for urine CXCL10: normal histology (n = 14), normal histology with BKV or CMV viremia (n = 19), tubulitis ≥2 (n = 15), pure microvascular inflammation (n = 41), and isolated v lesions (n = 14).

RESULTS

Elevated urinary CXCL10 reflected inflammation within the tubulointerstitial (urinary CXCL10/creatinine, 1.23 ng/mmol vs 0.46 ng/mmol; P = 0.02; area under the curve, 0.69; P = 0.001) and microvascular compartments (urinary CXCL10/creatinine, 1.72 ng/mmol vs 0.46 ng/mmol; P = 0.03; area under the curve, 0.69; P = 0.02) compared to normal histology. Intriguingly, urinary CXCL10 was predominantly elevated with peritubular capillaritis, but not glomerulitis (P = 0.04). Furthermore, urinary CXCL10 corresponded with BKV, but not CMV viremia (P = 0.02). These urine CXCL10 findings were confirmed in the independent validation set. Finally, serum CXCL10 was elevated with BKV and CMV viremia but was not associated with microvascular or vascular inflammation (P ≥ 0.19).

CONCLUSIONS

Urinary CXCL10 reflects subclinical inflammation within the tubulointerstitial and peritubular capillary spaces, but not the vascular/systemic compartments; this was consistent with BKV (tubulointerstitial) and CMV viremia (systemic). Serum CXCL10 was not a useful marker for (micro)vascular inflammation.

Identification of a urine metabolite constellation characteristic for kidney allograft rejection

INTRODUCTION

Allograft rejection is still an important complication after kidney transplantation. Currently, monitoring of these patients mostly relies on the measurement of serum creatinine and clinical evaluation. The gold standard for diagnosing allograft rejection, i.e. performing a renal biopsy is invasive and expensive. So far no adequate biomarkers are available for routine use.

OBJECTIVES

We aimed to develop a urine metabolite constellation that is characteristic for acute renal allograft rejection.

METHODS

NMR-Spectroscopy was applied to a training cohort of transplant recipients with and without acute rejection.

RESULTS

We obtained a metabolite constellation of four metabolites that shows promising performance to detect renal allograft rejection in the cohorts used (AUC of 0.72 and 0.74, respectively).

CONCLUSION

A metabolite constellation was defined with the potential for further development of an in-vitro diagnostic test that can support physicians in their clinical assessment of a kidney transplant patient.

Efficacy of the Sonoelastography Method for Diagnosis of Fibrosis in Renal Transplant Patients

OBJECTIVES

Although biopsy is the most important method for diagnosing the cause of renal allograft dysfunction, sonoelastography, a new ultrasonography method, can be used to distinguish between the soft or hard nature of lesions. In this study, our aim was to investigate whether sonoelastography could diagnose fibrosis in renal transplant patients.

MATERIALS AND METHODS

In this prospective study, we included patients over 18 years old who were recommended for clinical biopsy. Sonoelastographic evaluation was made by conducting acoustic radiation force impulse measurements for each patient after they were admitted to the clinic for biopsy. Measurements were performed just before the biopsy procedure. All results were examined by 2 experienced radiologists using the Siemens S3000 Ultrasound Machine (Erlangen, Germany). Comparisons of ultrasonographic values with biopsy results were made with SPSS software (SPSS: An IBM Company, version 20, IBM Corporation, Armonk, NY, USA).

RESULTS

Of the 65 patients included in this study, pathology showed acute T-cell-mediated rejection in 37 patients. There was a significant correlation between the pathologic Banff scores and the sonographic acoustic radiation force impulse values (P = .002), where the degree of Banff increased as the mean acoustic radiation force impulse values elevated. A rise in mean impulse values correlated with increased degree of interstitial fibrosis in renal allografts. Renal parenchymal echogenicity of patients significantly differed by sex (P = .009), with an average renal echogenicity of grade 1 in women and grade 0 in men. Also, a statistically significant difference was found between age of the renal transplant recipient and resistive index values.

CONCLUSIONS

Our study showed a significant correlation between Banff degree and the acoustic radiation force impulse values of renal transplant patients. In addition to biopsy, sonoelastography can be beneficial for the diagnosis of fibrosis in renal transplant patients.

Complications and adequacy of transplant kidney biopsies: A comparison of techniques

INTRODUCTION

Kidney biopsies are an essential tool in the diagnosis and management of kidney diseases, particularly in kidney transplant recipients. Biopsies carry a risk for serious complications and not all biopsies achieve adequate tissue. We examined the impact of kidney biopsy technique on complications and biopsy adequacy.

METHODS

The cohort consisted of consecutive kidney transplant patients undergoing biopsy by one of three techniques: ultrasound localization, real-time ultrasound guidance, and ultrasound-guided trocar placement. Variables of interest included patient characteristics and procedural characteristics. The primary outcome was serious complication attributable to kidney biopsy, and the secondary outcome was biopsy adequacy as defined by Banff criteria.

RESULTS

Among 263 patients undergoing biopsy, 27 (10.3%) had a complication (14 with gross hematuria, 10 requiring blood transfusion, 3 requiring an unplanned interventional radiology procedure, 1 kidney loss; no deaths). Complications were more common among patients biopsied using ultrasound-guided trocar compared to real-time ultrasound and ultrasound localization (21.4% vs 7.9% vs 7.1%, respectively, p = 0.008). After adjusting for patient and procedure characteristics, technique was no longer significantly associated with complication. Biopsy adequacy was significantly higher when using ultrasound localization and real-time ultrasound compared to ultrasound-guided trocar (84.6% vs 86.8% vs 69.6%, p = 0.029), and this finding persisted in adjusted analysis.

CONCLUSION

Kidney biopsy complications appear to be similar when using any of the three techniques examined in our study. However, ultrasound-guided trocar technique may yield lower biopsy adequacy when compared to non-trocar techniques.

Renal pseudoaneurysm formation post allograft biopsy: a case report

Renal pseudoaneurysm (PSA) is a rare complication post kidney transplant biopsy that accounts for less than 1% of allograft dysfunction. Imaging guidelines in the diagnosis of renal PSA have not yet been developed owing to the low occurrence and limited data availability. However, contrast-enhanced CT and magnetic resonance angiography (MRA) are the preferred modalities in detecting PSA owing to the high contrast and spatial resolution. However, magnetic resonance angiography is preferred since non-contrast imaging techniques can see blood flow patterns in renal PSA without the use of contrast media that may alter renal function. We present a rare complication in a 48-year-old male receiving a living related kidney transplant and found to have renal PSA post allograft biopsy. We review the clinical features, imaging and treatment outcome with the developed PSA in the transplanted kidney post allograft biopsy.

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.

High Resistive Index in Transplant Kidneys Is a Possible Predictor for Biopsy Complications

BACKGROUND

Transplant kidney biopsies are performed to determine a histological diagnosis for specific patient treatment. The aim of this study was to investigate if Resistive Index (RI) could be a predictor for biopsy complications.

METHODS

In this study, 220 consecutive transplant kidney biopsies (136 men and 84 women; median age, 55.5 years) were prospectively included. RI (median, 0.7) was measured by use of ultrasound. Histological diagnoses and biopsy complications were registered. Biopsy needles were either 16- or 18-gauge. Biopsies were performed by radiologists and were carried out as an outpatient procedure (70%) or an inpatient procedure (30%). Usually three passes per biopsy were performed.

RESULTS

The overall complication rate was 6.8%, divided into major (4.5%) and minor (2.3%) complications. An RI ≥0.8 predicts major (13.3% versus 3.2%; risk ratio [RR], 4.2; confidence interval [CI], 1.3-14.1; P = .03) and overall biopsy complications (16.7% versus 5.3%; RR, 3.2; CI, 1.2-8.6; P = .04) compared with RI <0.8. In the group <0.8, RI correlated with age (r_s = 0.28, P < .001) and systolic blood pressure (r_s = 0.18, P = .02). In the group ≥0.8, RI correlated with degree of interstitial fibrosis (r_s = 0.65, P = .006) and systolic blood pressure (r_s = 0.40, P = .03). The multiple regression analysis showed that in the group <0.8, the RI correlated only with age (P < .001), whereas in the group ≥0.8, RI correlated only with the degree of interstitial fibrosis (P = .003).

CONCLUSIONS

An RI ≥0.8 indicates greater risk for major and overall biopsy complications and should result in greater caution after biopsy.

Acute and Chronic Allograft Dysfunction in Kidney Transplant Recipients

Allograft dysfunction after a kidney transplant is often clinically asymptomatic and is usually detected as an increase in serum creatinine level with corresponding decrease in glomerular filtration rate. The diagnostic evaluation may include blood tests, urinalysis, transplant ultrasonography, radionuclide imaging, and allograft biopsy. Whether it occurs early or later after transplant, allograft dysfunction requires prompt evaluation to determine its cause and subsequent management. Acute rejection, medication toxicity from calcineurin inhibitors, and BK virus nephropathy can occur early or later. Other later causes include transplant glomerulopathy, recurrent glomerulonephritis, and renal artery stenosis.

Wedge Versus Core Biopsy at Time Zero: Which Provides Better Predictive Value for Delayed Graft Function With the Remuzzi Histological Scoring System?

BACKGROUND

Histopathological features on time-zero renal biopsies correlate with graft outcome after renal transplantation. With increasing numbers of marginal donors, assessment of pre-implantation graft quality is essential. The clinician's choice of wedge or core biopsy is performed without evidence of efficacy or safety. This study aims to compare the information derived from wedge biopsy versus core biopsy.

METHODS

Prospective evaluation of 37 wedge biopsies and 30 core biopsies was performed. Histopathological data were collected on number of glomeruli and arterioles observed, and Remuzzi scoring for glomerulosclerosis, tubular atrophy, interstitial fibrosis, and arteriolar narrowing was performed. Clinical data on delayed graft function (DGF) were also collated. Sensitivity, specificity, and positive and negative predictive values for DGF were compared.

RESULTS

Patient demographics between the two cohorts were comparable. No complications of biopsies occurred; 81% of wedge biopsies versus 50% of core biopsies had >10 glomeruli (P = .01), whereas 32% of wedge biopsies and 57% of core biopsies had >2 arterioles (P = .02). Wedge biopsies were more likely to identify pathology with more glomerulosclerosis, tubular atrophy (P < .01), and interstitial fibrosis (P < .01). There was a non-significant trend toward high Remuzzi scores in wedge biopsy (22% versus 7% with Remuzzi ≥ 4; P = .12). The sensitivity and positive predictive value of Remuzzi ≥ 4 for predicting DGF was better on wedge biopsy (45.5% versus 0%; P < .01 and 62.5% versus 0%; P < .01, respectively).

CONCLUSIONS

Wedge biopsies were safe and superior to core biopsies for identifying clinically significant histopathological findings on pre-implantation renal biopsy. We believe that the wedge biopsy is the method of choice for time-zero biopsies.

Urinary biomarkers of chronic allograft nephropathy

PURPOSE

Chronic allograft nephropathy (CAN) is widely accepted as the leading cause of renal allograft loss after the first year post transplantation. This study aimed to identify urinary biomarkers that could predict CAN in transplant patients.

EXPERIMENTAL DESIGN

The study included 34 renal transplant patients with histologically proven CAN and 36 renal transplant patients with normal renal function. OrbiTrap MS was utilized to analysis a urinary fraction in order to identify other members of a previously identified biomarker tree . This novel biomarker pattern offers the potential to distinguish between transplant recipients with CAN and those with normal renal function.

RESULTS

The primary node of the biomarker pattern was reconfirmed as β2 microglobulin. Three other members of this biomarker pattern were identified: neutrophil gelatinase-associated lipocalin, clusterin, and kidney injury biomarker 1. Significantly higher urinary concentrations of these proteins were found in patients with CAN compared to those with normal kidney function.

CONCLUSIONS AND CLINICAL RELEVANCE

While further validation in a larger more-diverse patient population is required to determine if this biomarker pattern provides a potential means of diagnosing CAN by noninvasive methods in a clinical setting, this study clearly demonstrates the biomarkers' ability to stratify patients based on transplant function.

Current Safety of Renal Allograft Biopsy With Indication in Adult Recipients: An Observational Study

Renal biopsy remains the golden standard diagnosis of renal function deterioration. The safety in native kidney biopsy is well defined. However, it is a different story in allograft kidney biopsy. We conduct this retrospective study to clarify the safety of allograft kidney biopsy with indication.All variables were grouped by the year of biopsy and they were compared by Mann-Whitney U test (for continuous variables) or Chi-square test (for categorical variables). We collected possible factors associated with complications, including age, gender, body weight, renal function, cause of uremia, status of coagulation, hepatitis, size of needle, and immunosuppressants.We recruited all renal transplant recipients undergoing allograft biopsy between January of 2009 and December of 2014. This is the largest database for allograft kidney biopsy with indication. Of all the 269 biopsies, there was no difference in occurrence among the total 14 complications (5.2%) over these 6 years. There were only 3 cases of hematomas (1.11%), 6 gross hematuria (2.23%), 1 hydronephrosis (0.37%), and 2 hemoglobin decline (0.74%). The outcome of this cohort is the best compared to all other studies, and it is even better than the allograft protocol kidney biopsy. Among all possible factors, patients with pathological report containing "medullary tissue only" were susceptible to complications (P < 0.001, 1.8 of relative risk).In modern era, this study demonstrates the safety of allograft kidney biopsy with indication. Identifying the renal capsule before biopsy to avoid puncture into medulla is the most important element to prevent complications.

Role for urinary biomarkers in diagnosis of acute rejection in the transplanted kidney

Despite the introduction of potent immunosuppressive medications within recent decades, acute rejection still accounts for up to 12% of all graft losses, and is generally associated with an increased risk of late graft failure. Current detection of acute rejection relies on frequent monitoring of the serum creatinine followed by a diagnostic renal biopsy. This strategy is flawed since an alteration in the serum creatinine is a late clinical event and significant irreversible histologic damage has often already occurred. Furthermore, biopsies are invasive procedures that carry their own inherent risk. The discovery of non-invasive urinary biomarkers to help diagnose acute rejection has been the subject of a significant amount of investigation. We review the literature on urinary biomarkers here, focusing on specific markers perforin and granzyme B mRNAs, FOXP3 mRNA, CXCL9/CXCL10 and miRNAs. These and other biomarkers are not yet widely used in clinical settings, but our review of the literature suggests that biomarkers may correlate with biopsy findings and provide an important early indicator of rejection, allowing more rapid treatment and better graft survival.

Urinary cell mRNA profiles predictive of human kidney allograft status

Kidney allograft status is currently characterized using the invasive percutaneous needle core biopsy procedure. The procedure has become safer over the years, but challenges and complications still exist including sampling error, interobserver variability, bleeding, arteriovenous fistula, graft loss, and even death. Because the most common type of acute rejection is distinguished by inflammatory cells exiting the intravascular compartment and gaining access to the renal tubular space, we reasoned that a kidney allograft may function as an in vivo flow cytometer and sort cells involved in rejection into urine. To test this idea, we developed quantitative polymerase chain reaction (PCR) assays for absolute quantification of mRNA and pre-amplification protocols to overcome the low RNA yield from urine. Here, we review our single center urinary cell mRNA profiling studies that led to the multicenter Clinical Trials in Organ Transplantation (CTOT-04) study and the discovery and validation of a 3-gene signature of 18S rRNA-normalized measures of CD3ε mRNA and IP-10 mRNA and 18S rRNA that is diagnostic and predictive of acute cellular rejection in the kidney allograft. We also review our development of a 4-gene signature of mRNAs for vimentin, NKCC2, E-cadherin, and 18S rRNA diagnostic of interstitial fibrosis/tubular atrophy (IF/TA).

Renal biopsy practice: What is the gold standard?

Renal biopsy (RB) is useful for diagnosis and therapy guidance of renal diseases but incurs a risk of bleeding complications of variable severity, from transitory haematuria or asymptomatic hematoma to life-threatening hemorrhage. Several risk factors for complications after RB have been identified, including high blood pressure, age, decreased renal function, obesity, anemia, low platelet count and hemostasis disorders. These should be carefully assessed and, whenever possible, corrected before the procedure. The incidence of serious complications has become low with the use of automated biopsy devices and ultrasound guidance, which is currently the “gold standard” procedure for percutaneous RB. An outpatient biopsy may be considered in a carefully selected population with no risk factor for bleeding. However, controversies persist on the duration of observation after biopsy, especially for native kidney biopsy. Transjugular RB and laparoscopic RB represent reliable alternatives to conventional percutaneous biopsy in patients at high risk of bleeding, although some factors limit their use. This aim of this review is to summarize the issues of complications after RB, assessment of hemorrhagic risk factors, optimal biopsy procedure and strategies aimed to minimize the risk of bleeding.

Outpatient renal needle biopsy of the transplanted kidney: safety profile

Since May 2005, we began performing renal graft biopsies as outpatient procedures when the patient's condition did not require hospitalization. To evaluate the safety profile of the 137 procedures performed in 111 patients, we performed a retrospective analysis of complications after all biopsies between 4 May 2005 and 6 January 6, 2011. The analysis focused on types of complications as well as needs for hospitalization with length of stay, for blood transfusion or for a further intervention. There were complications in 10.9% of procedures (n = 15) with 8% requiring hospitalization (n = 11). The complications were: gross hematuria (n = 10) including blockage of urinary flow (n = 2) with one subject requiring urologic intervention, and one patient experienced severe pain at the puncture site. Neither renal graft nor patient survival was threatened; there was no hemodynamic decompensation needing blood transfusions. The average hospital stay was 2.27 days (range = 1-8). Outpatient renal biopsies in 111 patients (137 procedures) had an 8% incidence of complications requiring admission and an average length of hospitalization of 2.27 days. Gross hematuria the most frequent problem, in no way compromised patient or graft survival showing it to be a safe outpatient procedure.

Allograft rejection and tubulointerstitial fibrosis in human kidney allografts: interrogation by urinary cell mRNA profiling

Because the kidney allograft has the potential to function as an in-vivo flow cytometer and facilitate the access of immune cells and kidney parenchymal cells in to the urinary space, we hypothesized that mRNA profiling of urinary cells offers a noninvasive means of assessing the kidney allograft status. We overcame the inherent challenges of urinary cell mRNA profiling by developing pre-amplification protocols to compensate for low RNA yield from urinary cells and by developing robust protocols for absolute quantification mRNAs using RT-PCR assays. Armed with these tools, we undertook first single-center studies urinary cell mRNA profiling and then embarked on the multicenter Clinical Trials in Organ Transplantation-04 study of kidney transplant recipients. We report here our discovery and validation of diagnostic and prognostic biomarkers of acute cellular rejection and of interstitial fibrosis and tubular atrophy (IF/TA). Our urinary cell mRNA profiling studies, in addition to demonstrating the feasibility of accurate diagnosis of acute cellular rejection and IF/TA in the kidney allograft, advance mechanistic and potentially targetable biomarkers. Interventional trials, guided by urinary cell mRNA profiles, may lead to personalized immunosuppression in recipients of kidney allografts.

Network analysis reveals roles of inflammatory factors in different phenotypes of kidney transplant patients

BACKGROUND

Systems-level characterization of inflammation in kidney transplantation remains incomplete. By stratifying kidney transplant patients based on phenotypes, the present study sought to identify the role of inflammatory proteins in disease progress and assess potential biomarkers for allograft monitoring.

METHODS

Kidney transplant patients with different allograft status were enrolled in the study: stable renal function (ST), impaired renal function (UNST), acute rejection (AR), and chronic rejection (CR). We stratified the patients into 3 phenotype levels according to their symptoms and pathogenesis. Serum protein concentrations were measured by a quantitative protein array. All differentially expressed proteins were analyzed by protein-protein interaction networks (PPINs) to highlight protein interactions in patients with the above dysfunction levels. We identified level-related proteins and evaluated the classification efficiency of these biomarkers based on leave-one-out validation. The candidate proteins related to phenotype transforming were annotated by Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis.

RESULTS

Based on the hypothesis that common proteins and their up- or down-regulation promote disease progress, we obtained 12 common proteins and 11 level-specific proteins from the phenotype-related PPINs. The common proteins were annotated for KEGG enrichment: (1) cytokine-cytokine receptor interaction; (2) hematopoietic cell lineage; (3) Jak-STAT signaling pathway; (4) allograft rejection; and (5) T cell receptor signaling pathway. The level-specific proteins could be potential biomarkers with diagnostic value. The classification potency of the 11 level-specific proteins (IL-1R-1, IL-16, TIMP-1, G-CSF, MIG, IL-11, BLC, TNF-β, Eotaxin-2, I-309 and IL-6 sR) was better than the performance using all 40 proteins.

CONCLUSION

The study demonstrated the potential value of PPINs-based approach to understanding inflammation-derived mechanisms and developing diagnostic biomarkers. Independent evaluations are required to further estimate the clinical relevance of the new diagnostic biomarkers.

Evaluation of transplanted kidneys using blood oxygenation level-dependent MRI at 3 T: a preliminary study

OBJECTIVE

The objective of our study was to investigate the feasibility and reproducibility of blood oxygenation level-dependent (BOLD) MRI using different gradient echoes at 3 T in patients with renal allografts and healthy volunteers and to evaluate whether BOLD MRI can be used to distinguish between cases of acute allograft rejection and normally functioning allografts.

SUBJECTS AND METHODS

BOLD MRI at 3 T was performed of eight patients with normal allografts, four patients with acute allograft rejection, and 10 healthy volunteers. Multiple fast-field echo sequences were performed at gradient echoes of 8, 16, and 20 to obtain T2(*)-weighted images. The reproducibility of BOLD MRI was evaluated in patients with normal allografts.

RESULTS

Cortical and medullary R2(*) values were not significantly different between healthy volunteers and patients with normal allografts, but medullary R2(*) values were significantly greater than cortical R2(*) values in both groups for all three protocols (p < 0.01). Medullary R2(*) values were significantly lower in cases of acute allograft rejection than in normal allografts for all three protocols (p < 0.001). The mean difference in cortical or medullary R2(*) values was 3.8% or less in all protocols.

CONCLUSION

BOLD MRI performed using different gradient echoes at 3 T is feasible and reproducible in patients with renal allografts and can show significant changes in medullary oxygenation in patients with acute rejection.

Surveillance biopsies in children post-kidney transplant

Surveillance biopsies are increasingly used in the post-transplant monitoring of pediatric renal allograft recipients. The main justification for this procedure is to diagnose early and presumably modifiable acute and chronic renal allograft injury. Pediatric recipients are theoretically at increased risk for subclinical renal allograft injury due to their relatively large adult-sized kidneys and their higher degree of immunological responsiveness. The safety profile of this procedure has been well investigated. Patient morbidity is low, with macroscopic hematuria being the most common adverse event. No patient deaths have been attributed to this procedure. Longitudinal surveillance biopsy studies have revealed a substantial burden of subclinical immunological and non-immunological injury, including acute cellular rejection, interstitial fibrosis and tubular atrophy, microvascular lesions and transplant glomerulopathy. The main impediment to the implementation of surveillance biopsies as the standard of care is the lack of demonstrable benefit of early histological detection on long-term outcome. The considerable debate surrounding this issue highlights the need for multicenter, prospective, and randomized studies.

[Renal biopsy practice: results of a French study and recommendations]

BACKGROUND

Although several risk factors associated with complications after renal biopsy (RB) have been identified, recommendations for RB procedures are still lacking. Our working group, appointed by the scientific commission of the Société de néphrologie in France, aimed to depict the main aspects of the practice of RB in adults in France, before establishing some guidelines.

METHODS

Members of the Société de néphrologie in France were asked to participate to a questionnaire survey on RB procedures.

RESULTS

Eighty-eight nephrologists from 74 units (27 in teaching hospitals, 35 in public general hospitals, and 12 in private centers) participated in our study. Native kidney and graft biopsies were performed in 73 and 35 units, respectively. RB activity was highly variable among units, ranging from several hundred to less than ten per year. Transjugular RB was judged to be smoothly accessible in 28 out of 73 units (38.4%). Significant variations in practices were observed regarding patient information before RB, assessment of hemorrhagic risk factors, care of patients with antiplatelet agents and hemorrhagic risk factors, and radiological guidance. Early discharge (<12 hours) was the rule in three (4.1%) units for native kidney biopsies and in ten (28.6%) units for graft biopsies.

CONCLUSIONS

Our study is the first to provide a representative picture of "everyday" RB practices in a country. Consensual recommendations on all points mentioned are provided here.

Peritransplant kidney biopsies: comparison of pathologic interpretations and practice patterns of organ procurement organizations

The preimplantation kidney biopsy affects utilization by diagnosing glomerulosclerosis, interstitial fibrosis (IF), arteriosclerosis, and arteriolar hyalinosis. Organ procurement organizations (OPOs) determine whether a donor warrants this biopsy and the donor hospital pathologists (DHPs) report on an OPO-specific pathology interpretation form. Biopsy slides from 40 deceased donor kidneys transplanted at our institution were used to compare interpretations between our transplant pathologist and the DHPs. Thirty-three of these kidneys also had post-perfusion biopsies (PPB). All 58 OPOs were queried for criteria used to request a preimplantation biopsy, and their pathology interpretation forms were also analyzed. The transplant and DHPs had substantial agreement for percent glomerulosclerosis with 75% of biopsies being interpreted within five percentage points. Concordance for IF was poor. The DHP rarely reported arterial pathology. Seventy percent of preimplantation and PPB were read similarly for glomerulosclerosis; concordance for other lesions was weaker. There were no cues for arterial disease on our OPO's pathology interpretation form. Criteria for obtaining a preimplantation biopsy lacked uniformity for the 21 OPOs with a self-generated policy. The pathology interpretation forms varied widely among the OPOs. Current OPO practices with regard to the preimplantation biopsy should be improved.

Identification of β2-microglobulin as a urinary biomarker for chronic allograft nephropathy using proteomic methods

PURPOSE

Chronic allograft nephropathy (CAN) remains the leading cause of renal graft loss after the first year following renal transplantation. This study aimed to identify novel urinary proteomic profiles, which could distinguish and predict CAN in susceptible individuals.

EXPERIMENTAL DESIGN

The study included 34 renal transplant patients with histologically proven CAN and 36 patients with normal renal transplant function. High-throughput proteomic profiles were generated from urine samples with three different ProteinChip arrays by surface-enhanced laser-desorption/ionization time-of-flight mass spectrometry (SELDI-TOF-MS). Following SELDI, a biomarker pattern software analysis was performed which led to the identification of a novel biomarker pattern that could distinguish patients with CAN from those with normal renal function.

RESULTS

An 11.7 kDa protein identified as β2 microglobulin was the primary protein of this biomarker pattern, distinguishing CAN from control patients (receiver operator characteristic [ROC]=0.996). SELDI-TOF-MS comparison of purified β2 microglobulin protein and CAN urine demonstrated identical 11.7 kDa protein peaks. Significantly, higher concentrations of 2 microglobulin were found in the urine of patients with CAN compared with the urine of normal renal function transplant recipients (p<0.001).

CONCLUSIONS AND CLINICAL RELEVANCE

Although further validation in a larger more diverse patient population is required to determine if this β2 microglobulin protein biomarker will provide a potential means of diagnosing CAN by noninvasive methods in a clinical setting, this study clearly shows a capability to stratify control and disease patients.

Renal biopsy in type 2 diabetes: timing of complications and evaluating of safety in Chinese patients

AIM

It has been recognized that renal lesions in patients with diabetes often have other causes of renal damage concomitantly. Renal biopsy is a valuable tool to provide histological evidence. However, the safety in patients with type 2 diabetes receiving renal biopsy is not well evaluated. This study was conducted to monitor the dynamic complications and to evaluate the safety of biopsy in diabetic patients.

METHODS

A prospective observation was performed on 130 patients with type 2 diabetes and 150 patients not undergoing renal biopsy. The complications were monitored at 4 h, 8 h, 24 h, 48 h and 72 h sequentially after biopsy.

RESULTS

Haematoma was observed in 34 (26.15%) patients with diabetes and 50 (33.33%) in controls (P=0.19). The timing of large haematoma peaked at 4 h. Gross haematuria occurred in 12 (9.23%) diabetic patients and eight (5.33%) controls (P=0.207). It happened mainly within 8 h. Renal pathological diagnosis showed 96 (73.85%) cases with diabetic nephropathy and 34 (26.15%) cases with non-diabetic renal disease.

CONCLUSION

Renal biopsy in patients with type 2 diabetes is safe. The frequency of complications after renal biopsy in diabetes is no higher than those without diabetes. The complications mostly happened within 8 h, especially within 4 h. Biopsy is also very necessary to rule out other chronic renal diseases in diabetes.

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.

Proteomic profiling of renal allograft rejection in serum using magnetic bead-based sample fractionation and MALDI-TOF MS

Proteomics is one of the emerging techniques for biomarker discovery. Biomarkers can be used for early noninvasive diagnosis and prognosis of diseases and treatment efficacy evaluation. In the present study, the well-established research systems of ClinProt Micro solution incorporated unique magnetic bead sample preparation technology, which, based on matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS), have become very successful in bioinformatics due to its outstanding performance and reproducibility for discovery disease-related biomarker. We collected fasting blood samples from patients with biopsy-confirmed acute renal allograft rejection (n = 12), chronic rejection (n = 12), stable graft function (n = 12) and also from healthy volunteers (n = 13) to study serum peptidome patterns. Specimens were purified with magnetic bead-based weak cation exchange chromatography and analyzed with a MALDI-TOF mass spectrometer. The results indicated that 18 differential peptide peaks were selected as potential biomarkers of acute renal allograft rejection, and 6 differential peptide peaks were selected as potential biomarkers of chronic rejection. A Quick Classifier Algorithm was used to set up the classification models for acute and chronic renal allograft rejection. The algorithm models recognize 82.64% of acute rejection and 98.96% of chronic rejection episodes, respectively. We were able to identify serum protein fingerprints in small sample sizes of recipients with renal allograft rejection and establish the models for diagnosis of renal allograft rejection. This preliminary study demonstrated that proteomics is an emerging tool for early diagnosis of renal allograft rejection and helps us to better understand the pathogenesis of disease process.

Incidence of bleeding after 15,181 percutaneous biopsies and the role of aspirin

OBJECTIVE

The objective of our study was to report the incidence of bleeding after imaging-guided percutaneous core biopsy at a single center using a standardized technique.

MATERIALS AND METHODS

We performed a retrospective review of percutaneous core biopsies performed at our institution from January 2002 through February 2008. Data were collected at the time of biopsy, and clinical information was obtained 24 hours and 3 months after the biopsy. The specific information that was collected included the results of coagulation studies, aspirin use, the organ biopsied, the size of the biopsy needle, and the number of needle passes. Bleeding complications were defined using the Common Terminology Criteria for Adverse Events (CTCAE, version 3.0) established by the National Cancer Institute.

RESULTS

Among the 15,181 percutaneous core biopsies performed during the study period, 70 hemorrhages (0.5%) that were CTCAE grade 3 or greater were identified within 3 months of biopsy. The incidence of bleeding in patients taking aspirin within 10 days before biopsy was 0.6% (18/3,195), which was not statistically different compared with the incidence of bleeding in those not taking aspirin (52/11,986, 0.4%; p = 0.34). The incidence of bleeding after liver biopsy was 0.5%; kidney biopsy, 0.7%; lung biopsy, 0.2%; pancreas biopsy, 1.0%; and other biopsy, 0.2%. There were significant associations between major bleeding and serum platelet count and international normalized ratio (p < 0.001), although the association between major bleeding and the size of the biopsy needle was not significant (p = 0.97).

CONCLUSION

The overall incidence of major bleeding after imaging-guided percutaneous core needle biopsy is low. Recent aspirin therapy does not appear to significantly increase the risk of such bleeding complications.