Management of Vascular and Nonvascular Complications After Renal Transplantation

Use of fibrin sealant in vein anastomosis in renal transplantation and its effect in preventing blood loss and postoperative peri-graft collection

PURPOSE

This study is to assess efficacy of fibrin sealant in vein anastomosis in renal transplantation in preventing blood loss and postoperative peri-graft collection.

METHODS

This is a retrospective analytical case-control study of renal transplantations done in a tertiary care center in India in a 1-year period. Fibrin sealant was randomly used in vein anastomosis during the period. All the data were extracted and retrospectively analyzed. Those with fibrin sealant use were the study group and without sealant use were the control group. Primary objective was to assess effectiveness of fibrin sealant in preventing blood loss and postoperative peri-graft collection. Secondary objectives were to evaluate patients' demographic profile, hospital stay and other intraoperative and postoperative characteristics.

RESULTS

During the study, 163 patients were enrolled, 82 study group and 81 control group. Warm ischemia, cold ischemia and operative times of study group were 2.57 ± 2.03, 44.23 ± 8.89 and 189.6 ± 51.6 min, respectively, and that of control group were 2.67 ± 2.07, 42.37 ± 8.5 and 178.8 ± 54.6 min, respectively. The mean intraoperative blood loss in study and control groups was 124.83 ± 110.89 and 155 ± 50.27 ml, respectively, and the difference was statistically significant (p .027). The mean peri-graft collection in study group and control group were 72.33 ± 29.18 ml and 134.67 ± 102.84 ml, respectively, but the difference was not statistically significant (p .086). The study also demonstrated that the duration of hospital stays significantly differed between two groups (p < .043).

CONCLUSION

In this study, fibrin sealant has demonstrated both safety and efficacy in effectively managing bleeding, sealing vascular anastomoses, and mitigating peri-graft collection.

Case report: Endovascular treatment of transplant renal artery stenosis in patient with normal color duplex ultrasound of the renal artery

Key Clinical Message

Proper diagnosis and treatment of vascular stenosis which is a possible complication of renal transplant is important in improving patients' quality of life and prognosis.

Abstract

One known consequence among recipients of renal transplants is graft renal artery stenosis. Early identification and therapy are crucial to avoid graft malfunction and the serious consequences that might arise due to elevated hypertension in several organs. We report a rare case of transplant renal artery stenosis in a mid-aged woman who presented with edema, hypertension, and increased creatinine 2 months after kidney transplant. The patient had normal renal arterial resistive index (RI) and perfusion index (PI), and there was only a modest decrease in perfusion on duplex ultrasound. Following the patient's renal stenting treatment, angiographic resolution was observed. After 14 days of regulated blood pressure following renal artery stenting, she was discharged from the hospital with her edema resolved. Considering complications in patients with clinical manifestations such as hypertension resistant to treatment and graft dysfunction, vascular stenosis is a notable issue to consider even in the context of normal renal arterial RI, PI, and duplex ultrasound. Proper diagnosis and treatment are of importance to improve patients' quality of life and prognosis.

Transplant Renal Interventions

Renal transplantation is the most commonly performed solid-organ allograft surgery; in 2021, 25487 kidneys were transplanted in the United States, and nearly 42,000 adult patients were listed for transplant. As the treatment of choice for patients with end-stage renal disease, transplantation is performed at more than 250 centers. Despite a high rate of success, renal transplantation is not without complication, and the interventional radiologist plays a crucial role in the management of the postoperative patient. Knowledge of postsurgical anatomy, imaging findings, and technical challenges unique to these patients is important for the safe and effective treatment of transplant-related conditions. We offer a guide to the most common interventions in the renal transplant population, including biopsy, vascular interventions, and the management of urinary obstruction.

Association between the Three Polymorphisms of the Glucocorticoid Receptor Gene and the Early Clinical Outcome in Kidney Transplantation Patients

Background:

Glucocorticoids are pivotal components of immunosuppressive regimens in solid organ transplantations. This study aimed to assess the possible association between the ER22/23EK, N363S, and Bcl1 polymorphisms, and short-term clinical outcomes, including acute rejection and delayed graft function (DGF), in kidney transplantation recipients.

Methods:

A case-control study was conducted in a two-year period on adults with transplanted kidneys, comprised of subjects without rejection (n=50, control) and those with documented rejection within one year after transplantation (n=50, case), between April 2017 and September 2018, in Shiraz, Iran. Demographic characteristics and clinical and paraclinical findings were gathered. The genotyping of the ER22/23EK, N363S, and Bcl1 polymorphisms was carried out via polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The association between the genotypes and DGF as well as rejection types was evaluated using either the Chi square test or Fisher exact test. A stepwise logistic regression analysis was conducted to determine the independent factors of acute rejection within the first year after transplantation.

Results:

The study population consisted of 64 men and 36 women. The frequency of mutated alleles was 0.32 for G (Bcl1), 0.02 for S (N363S), and 0.065 for A (ER22/23EK). There was no significant association either between the studied polymorphisms and acute rejection or between the Bcl1 (P=0.17), N363S (P=0.99), and ER22/23EK (P=0.99) genotypes and DGF. The length of hospital stay after kidney transplantation was slightly more in N363N and ER22/23EK wild allele carriers. However, this difference was not statistically significant.

Conclusion:

Our data suggested no statistically significant association between the genotypes of the studied polymorphisms and early clinical outcomes after kidney transplantation.

Imaging non-vascular complications of renal transplantation

In patients with end-stage renal disease, the treatment of choice for most patients is renal transplantation. Complications that occur after kidney transplant can be broadly divided into vascular and non-vascular categories. Non-vascular complications can further be divided into surgical and medical categories. When evaluating renal transplant imaging, it is helpful to consider the occurrence of complications in a timeline from time of surgery. Ultrasound is often the first modality used for evaluation of renal transplants particularly in the early postoperative period. Contrast-enhanced ultrasound can be a helpful adjunct in evaluating certain complications such as hematoma, rejection, and infection. Computed tomography (CT) is also helpful in accurately diagnosing complications. Surgical complications include perinephric fluid collections (hematoma, urinoma from urine leak, abscess, and lymphocele), urinary obstruction, and incisional fluid collections and hernias. One major category of medical complications that affect the renal parenchyma includes rejection (hyperacute, acute, and chronic), delayed graft function, acute tubular necrosis (ATN), and nephrotoxicity. Infection, renal calculi, and neoplasms such as post-transplant lymphoproliferative disease are medical complications that occur after renal transplantation. It is important for radiologists to be aware of the ultrasound and CT findings of the surgical and medical complications after renal transplant for prompt identification and treatment.

Standardized Duplex Ultrasound-Based Protocol for Early Diagnosis of Transplant Renal Artery Stenosis: Results of a Single-Institution Retrospective Cohort Study

Transplant renal artery stenosis (TRAS) is the most frequent vascular complication after kidney transplantation (KT) and has been associated with potentially reversible refractory hypertension, graft dysfunction, and reduced patient survival. The aim of the study is to describe the outcomes of a standardized Duplex Ultrasound- (DU-) based screening protocol for early diagnosis of TRAS and for selection of patients potentially requiring endovascular intervention. We retrospectively reviewed our prospectively collected database of KT from January 1998 to select patients diagnosed with TRAS. The follow-up protocol was based on a risk-adapted, dynamic subdivision of eligible KT patients in different risk categories (RC) with different protocol strategies (PS). Of 598 patients included in the study, 52 (9%) patients had hemodynamically significant TRAS and underwent percutaneous angioplasty (PTA) and stent placement. Technical and clinical success rates were 97% and 90%, respectively. 7 cases of restenosis were recorded at follow-up and treated with re-PTA plus stenting. Both DU imaging and clinical parameters improved after stent placement. Prospective high-quality studies are needed to test the efficacy and safety of our protocol in larger series. Accurate trial design and standardized reporting of patient outcomes will be key to address the current clinical needs.

[A high level of high-density lipoprotein cholesterol is a protective factor against transplant renal artery stenosis]

OBJECTIVE

To investigate the factors associated with the occurrence of transplant renal artery stenosis (TRAS).

METHODS

A retrospective analysis was conducted in 26 recipients who developed TRAS and 40 concurrent renal recipients without TRAS. We also conducted a nested case-control study in 14 patients with TRAS (TRAS-SD group) and another 14 non-TRAS recipients who received the allograft from the same donor (non-TRAS-SD group).

RESULTS

Compared with those in the concurrent recipients without TRAS, acute rejection (AR) occurred at a significantly higher incidence (P=0.004) and the warm ischemia time (WIT) was significantly longer (P=0.015) and the level of high?density lipoprotein cholesterol (HDL--C) significantly lower (P=0.009) in the recipients with TRAS. Logistic regression analysis suggested that AR (P=0.007) and prolonged WIT (P=0.046) were risk factors of TRAS while HDL-C (P=0.022) was the protective factor against TRAS. In recent years early diagnosis of TRAS had been made in increasing cases, the interval from transplantation to TRAS diagnosis became shortened steadily, and the recipients tended to have higher estimated glomerular filtration rate at the time of TRAS diagnosis.

CONCLUSION

Apart from the surgical technique, AR and prolonged WIT are also risk factors of TRAS while a high HDL-C level is the protective factor against TRAS. The improvement of the diagnostic accuracy by ultrasound is the primary factor contributing to the increased rate of early TRAS diagnosis in recent years.

Interventional Therapy for Transplant Renal Artery Stenosis Is Safe and Effective in Preserving Allograft Function and Improving Hypertension

Purpose:

To evaluate the outcomes of percutaneous intervention (PI) for transplant renal artery stenosis (TRAS).

Materials and Methods:

Doppler ultrasonography was used as the screening tool, and angiography was the diagnostic method for TRAS. The indications for PI were (1) a reduction in lumen diameter of >50% or (2) a mean pressure gradient of >15 mm Hg. Technical success was assessed immediately after the procedure. The short-term results of stenosis were evaluated by serum creatinine (Scr) levels and blood pressure (BP). The long-term results were assessed by graft survival and renal function.

Results:

From October 2009 to July 2015, a total of 660 patients had kidney transplantation and 22 cases underwent PI. The technical success was 100%. The mean Scr level preintervention was 321.6 ± 167.2 (range, 171.3-862.0) μmol/L, and it decreased to 145.3 ± 44.7 (range, 74.3-260.8) μmol/L 1 month postintervention ( P < .001). Blood pressure was also improved at 1 month postintervention, as assessed by systolic (157.0 ± 13.0 vs 131.0 ± 11.0 mm Hg, P < .001), diastolic (95.0 ± 5.0 vs 77.0 ± 9.0 mm Hg, P < .001), and mean arterial pressure (116.0 ± 7.0 vs 95.0 ± 9.0 mm Hg, P < .001). The patency rate was 100%, 91.7%, and 85.7% at 1, 3, and 12 months, respectively. The secondary patency rate was 100%. Graft survival was 100% during follow-up. There was no significant deterioration in graft function or BP ( P > .05) postintervention when compared to posttransplantation.

Conclusions:

Percutaneous intervention for TRAS is safe and results in significant improvement both in allograft function and in BP.

Interventional Management of Vascular Renal Transplant Complications

Renal transplantation is the therapy of choice in patients with end stage renal disease. Although transplant rejection remains the most common complication after renal transplantation, vascular anatomical complications occur in 1%-23% of renal transplant recipients. Interventional radiologists play an important role in the management of these complications. This review discusses the role of image-guided interventions within the context of multidisciplinary patient management. Particular emphasis is given to anatomical considerations unique to this patient population, techniques used for image-guided interventions, and outcomes of image-guided interventions.

Clinical applications of diffusion-weighted magnetic resonance imaging in diagnosis of renal lesions - a systematic review

Diffusion-weighted magnetic resonance imaging (DW-MRI) is an established technique to detect the changes of the diffusion of water in biological tissues and reflect the pathophysiological process on the molecular level. It is a promising non-invasive imaging modality in detection of microstructural and functional changes in pathologies of kidney. To systematically review the research advancement of the DW-MRI in diagnosis of renal lesions, a systematic literature search was performed up to 8 October 2014 using the MEDLINE/PubMed and Embase databases for articles reporting on DW-MRI in diagnosis of renal lesions. Only articles with full data about DW-MRI application with potential implication in solving usually encountered clinical challenges about renal lesions were finally examined. The clinical application of DW-MRI allows a better understanding of some pathologic conditions of the kidney including renal insufficiency, renal artery stenosis, ureteral obstruction, foetal kidney disease, hydronephrosis and pyonephrosis. In addition, DW-MRI can also provide clinicians with the information of function evaluation of renal allograft and curative effect assessment of renal tumour. In summary, performance of renal DW-MRI, presuming that measurements are high quality, will further boost this modality, particularly for early detection of diffusion renal conditions, as well as more accurate characterization of renal lesions.

Successful technical and clinical outcome using a second generation balloon expandable coronary stent for transplant renal artery stenosis: Our experience

Transplant renal artery stenosis (TRAS) is a vascular complication frequently seen because of increase in the number of renal transplantations. Early diagnosis and management is essential to optimize a proper graft function. Currently, the endovascular treatment of TRAS using angioplasty and/or stenting is considered the treatment of choice with the advantage that it does not preclude subsequent surgical correction. Treatment of TRAS with the use of stents, particularly in tortuous transplant renal anatomy presents a unique challenge to an interventional radiologist. In this study, we present three cases from our practice highlighting the use of a balloon-expandable Multi-Link RX Ultra coronary stent system (Abbott Laboratories, Abbott Park, Illinois, USA) for treating high grade focal stenosis along very tortuous renal arterial segments. Cobalt-Chromium alloy stent scaffold provides excellent radial force, whereas the flexible stent design conforms to the vessel course allowing for optimal stent alignment.

Minimally invasive salvage therapy for transplanted renal allografts

PURPOSE

To evaluate the effectiveness of interventional therapy for complications of transplanted renal allografts.

MATERIALS AND METHODS

Between January 2009 and March 2014, 14 patients underwent interventional therapy for complications of renal allografts. Complications included transplant renal artery stenosis (TRAS), TRAS combined with pseudoaneurysms, transplant renal venous kinking and ureteral obstruction (UO). Serum creatinine (S.Cr) levels were evaluated before and after procedure. The characteristics and procedure outcomes of these patients with vascular and nonvascular complications were also analyzed.

RESULTS

All primary procedures were successfully performed, which included percutaneous transluminal angioplasty (PTA) for TRAS (n = 4), stenting and coil embolization for TRAS combined with pseudoaneurysms (n = 1), stenting for renal vein kinking (n = 2), and percutaneous nephrostomy (PCN) for UO (n = 7) and secondary antegrade stent placement in six UO patients after 1 week of PCN. No major procedure related complications occurred. S.Cr level subsequently improved from 6.0 ± 3.6 to 2.6 ± 2.1 mg/dL (p < 0.001), as well as patients' clinical features within 1 week after procedure. In our study, the onset time of vascular complications was earlier (<6 months) than nonvascular complications with significant difference (p < 0.001). During follow-up, the patient with TRAS and pseudoaneurysms suffered acute rejection 1 month after treatment and received transplant renal artery embolization. One patient with TRAS showed restenosis 4 months after procedure, and was retreated successfully with stenting. Thirteen cases reserved their transplanted renal allografts.

CONCLUSION

Interventional therapy could be prior considered for transplanted renal allograft complications as its effectiveness and minimal invasiveness in saving the transplanted renal grafts.

Iatrogenic-related transplant injuries: the role of the interventional radiologist

As advances in surgical techniques and postoperative care continue to improve outcomes, the use of solid organ transplants as a treatment for end-stage organ disease is increasing. With the growing population of transplant patients, there is an increasing need for radiologic diagnosis and minimally invasive procedures for the management of posttransplant complications. Typical complications may be vascular or nonvascular. Vascular complications include arterial stenosis, graft thrombosis, and development of fistulae. Common nonvascular complications consist of leaks, abscess formation, and stricture development. The use of interventional radiology in the management of these problems has led to better graft survival and lower patient morbidity and mortality. An understanding of surgical techniques, postoperative anatomy, radiologic findings, and management options for complications is critical for proficient management of complex transplant cases. This article reviews these factors for kidney, liver, pancreas, islet cell, lung, and small bowel transplants.

Interventional radiological treatment of renal transplant complications: a pictorial review

Renal transplantation is the treatment of choice for patients with chronic renal failure, which produces a dramatic improvement in the quality of life and survival rates, in comparison to long-term dialysis. Nowadays, new imaging modalities allow early diagnosis of complications, and thanks to the recent developments of interventional techniques, surgery may be avoided in most cases. Knowledge in the types of renal transplant complications is fundamental for a correct pre-operative planning. In this article, we described the most common or clinically relevant renal transplant complications and explained their interventional management.

Outcomes of Percutaneous Management of Anastomotic Ureteral Strictures in Renal Transplantation: Chronic Nephroureteral Stent Placement with and without Balloon Dilatation

PURPOSE

This study was designed o evaluate outcomes of percutaneous management of anastomotic ureteral strictures in renal transplants using nephroureteral stents with or without balloon dilatation.

METHODS

A retrospective audit of 1,029 consecutive renal transplants was performed. Anastomotic ureteral strictures were divided into two groups: nephroureteral stent only (NUS) and NUS+PTA (nephroureteral stent plus percutaneous transluminal angioplasty), with each cohort subdivided into early versus late presentation (obstructive uropathy occurring <90 day or >90 days from transplant, respectively). Overall and 6-month technical success were defined as removal of NUS any time with <30 % residual stenosis (any time lapse less or more than 6 months) and at >6 months, respectively. Patency was evaluated from NUS removal to last follow-up for both groups and compared.

RESULTS

Sixty-seven transplant patients with 70 ureteric anastomotic strictures (6.8 %, n = 70/1,029) underwent 72 percutaneous treatments. 34 % were late (>90 days, n = 24/70), and 66 % were early (<90 days, n = 46/70). Overall technical success was 82 % (n = 59/72) and 6-month success was 58 % (n = 42/72). Major and minor complications were 2.8 % (n = 2/72), and 12.5 % (n = 9/72). NUS+PTA did not improve graft survival (p = 0.354) or patency (p = 0.9) compared with NUS alone. There was no difference in graft survival between treated and nontreated groups (p = 0.74).

CONCLUSIONS

There is no advantage to PTA in addition to placement of NUS, although PTA did not negatively impact graft survival or long-term patency and both interventions were safe and effective. Neither the late or early groups benefited from PTA in addition to NUS. Earlier obstructions showed greater improvement in serum creatinine than later obstructions.

Complications of transplantation. Part 1: renal transplants

Vascular complications after solid-organ transplantation are not uncommon and may lead to graft dysfunction and ultimately graft loss. A thorough understanding of the surgical anatomy, etiologies, and types of vascular complications, their presentation, and the options for management are important for managing these complex patients. This article reviews the basic surgical anatomy, vascular complications, and endovascular management options of vascular complications in patients with renal transplants.

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.

Magnetic resonance with diffusion-weighted imaging in the evaluation of transplanted kidneys: preliminary findings

BACKGROUND

The aim of this study was to compare values of apparent diffusion coefficient (ADC) and diffusion (D) with renal function indexes, in a population of kidney transplant recipients who underwent magnetic resonance with diffusion-weighted imaging (DWI) of the transplanted graft.

MATERIALS AND METHODS

We studied 21 patients using a 1.5-Tesla magnetic resonance; DWI sequences were acquired with several b-values. Patients were divided into 3 groups by their creatinine clearance values: group A, clearance >60 mL/min; group B, clearance >30 and ≤60 mL/min; and group C, clearance ≤30 mL/min. ADCs values between groups were compared using the Mann-Whitney U test. Receiver operating characteristic (ROC) curves were created for prediction of normal renal function (group A) and renal failure (group C).

RESULTS

Comparing mean values of ADC between groups A and C, we observed a difference (P=0.0012), with higher values in group A. Regarding mean values of D, we observed a difference between groups A and C (P=0.022). In the comparison between contiguous groups, we observed no difference for ADC and D values. In the prediction of normal clearance values (group A), ROC curve showed an area under curve (AUC) of 0.861, with a sensitivity of 88.89% and specificity of 75% using a threshold ADC value ≥2.1 × 10(-3) mm(2)/sec. For prediction of normal clearance values (group A), ROC curve showed an AUC of 0.787, with a sensitivity of 77.8% and specificity of 83.3% using a threshold D value ≥2.3 × 10(-3) mm(2)/sec.

CONCLUSION

Although studies with a larger number of patients are needed, DWI represents a promising tool for noninvasive assessment of renal function. An ADC ≥ 2.1 × 10(-3) mm(2)/sec and a D ≥ 2.3 × 10(-3) mm(2)/sec may be used as a threshold for predicting normal clearance.

Close to transplant renal artery stenosis and percutaneous transluminal treatment

Purpose. To evaluate the efficacy of percutaneous transluminal angioplasty (PTA) in the management of arterial stenosis located close to the allograft anastomosis (close-TRAS). Materials and Methods. 31 patients with renal transplants were admitted to our institution because of persistent hypertension and impairment of transplant renal function and underwent angiography for vascular investigation. 27 were diagnosed suffering from transplant renal artery stenosis (TRAS), whereas 4 had severe iliac artery stenosis proximal to the transplant anastomosis (Prox-TRAS). 3 cases of TRAS coexisted with segmental renal arterial stenosis, whereas 3 other cases of TRAS were caused by kinking and focal stenosis in the middle of the transplanted renal artery. Results. Angioplasty and stenting were successfully applied to all patients with iliac artery stenosis as well as to those with TRAS and segmental artery stenosis. Two of three patients with kinking were well treated with angioplasty and stenting, whereas one treated only with angioplasty necessitated surgery. No major procedure-related complications appeared, and the result was decrease of the serum creatinine level and of the blood pressure. Conclusions. PTA is the appropriate initial treatment of TRAS and close-TRAS, with low morbidity and mortality rates, achieving improvement of graft function and amelioration of hypertension.