Interventional therapy of vascular complications following renal transplantation

Artificial Intelligence Algorithm-Based MRI in the Diagnosis of Complications after Renal Transplantation

This study was to explore the diagnostic value of magnetic resonance imaging (MRI) optimized by residual segmentation attention dual channel network (DRSA-U-Net) in the diagnosis of complications after renal transplantation and to provide a more effective examination method for clinic. 89 patients with renal transplantation were selected retrospectively, and all underwent MRI. The patients were divided into control group (conventional MRI image diagnosis) and observation group (MRI image diagnosis based on DRSA-U-Net). The accuracy of MRI images in the two groups was evaluated according to the comprehensive diagnostic results. The root mean square error (RMSE) and peak signal-to-noise ratio (PSNR) of DRSA-U-Net on T1WI and T2WI sequences were better than those of U-Net and dense U-Net $\left(P<0.05\right)$ ; comprehensive examination showed that 39 patients had obstruction between ureter and bladder anastomosis, 13 cases had rejection, 10 cases had perirenal hematoma, 5 cases had renal infarction, and 22 cases had no complications; the diagnostic sensitivity, specificity, accuracy, and consistency of the observation group were higher than those of the control group $\left(P<0.05\right)$ . In the control group, the sensitivity, specificity, and accuracy in the diagnosis of complications after renal transplantation were 66.5%, 84.1%, and 78.32%, respectively; in the observation group, the sensitivity, specificity, and accuracy in the diagnosis were 67.8%, 86.7%, and 80.6%, respectively. DRSA-U-Net denoising algorithm can clearly display the information of MRI images on the kidney, ureter, and surrounding tissues, improve its diagnostic accuracy in complications after renal transplantation, and has good clinical application value.

Endovascular treatment of an immediate postoperative transplant renal artery stenosis with a polymer free drug eluting stent

The transplant renal artery stenosis occurred up to 23% after kidney transplantation. Endovascular treatment has become the treatment of choice of this complication, but could be challenging in immediate postoperative anastomotic narrowing. We report the case of a adolescent with early renal graft artery stenosis located in the anastomosis and diagnosed 3 days after renal transplantation, with necessity of haemodialysis. This complication was treated by angioplasty on the 25th day, using a polymer free drug eluting stent with a good result. We discussed the precautions and technical features of this procedure.

Surgical Complications After Kidney Transplantation

Since the first successful organ transplant conducted between twins in 1954, kidney transplant has evolved considerably over the past 50 years. Kidney transplant plays an important role in the treatment of end-stage kidney disease to improve the quality of life and prolong the life of patients. Despite significant advances, postoperative medical and surgical complications still represent important causes of morbidity and mortality. Many problems can be avoided through prophylactic correction of abnormalities detected during the preoperative evaluation; however, it is critical that technical mishaps at all stages of the transplant process (donor nephrectomy, benchwork preparation, and implant) be prevented and that careful postoperative monitoring be carried out, including thorough examination by attending physicians. However, despite these advances, surgical complications still present serious problems in kidney transplant recipients.

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.

Acute renal artery thrombosis after kidney transplantation

Early kidney transplant loss as a result of acute thrombosis of the renal artery remains a constant and devastating complication, with an incidence of 0.2-7.5%. While uncommon, arterial obstruction in the early postoperative period is a surgical emergency and must be ruled out if previously established diuresis ceases suddenly. Arterial thrombosis may occur as a result of injury to a diseased artery, problems with anastomoses, hypercoagulability or malpositioning of the allograft. In this study, we analyzed data on a group of 105 renal transplant recipients who presented with acute postoperative graft dysfunction between January 2006 and May 2012, to identify cases of acute renal artery thrombosis. We report on our experience of immediate re-transplantation following early kidney transplant thrombosis. Overall, two (1.9%) patients suffered early (within 48 hours of surgery) allograft renal artery thrombosis. In both patients, transplantation had not been complicated by atherosclerotic lesions or other thrombophilic states and postoperative diuresis had been successfully achieved, but diuresis ceased abruptly during the early postoperative period. Emergent duplex ultrasound scans were performed and acute renal artery thrombosis was detected in both patients. The patients were operated immediately and retransplantation procedures were conducted. We have reported our experience of immediate retransplantation following early primary graft dysfunction due to renal artery thrombosis. In conclusion, close monitoring of postoperative diuresis and, if necessary, immediate retransplantation in this situation can prove to be a successful treatment for preventing graft loss.

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.

Analysis of vascular complications after renal transplantation

PURPOSE

Despite medical and surgical advances, vascular complications remain common after renal transplant, occurring among 3%-15% of patients. These complications may compromise graft function. This study sought to evaluate the frequency and management of vascular complications after renal transplant.

MATERIALS AND METHODS

We retrospectively analyzed the 1843 transplantations performed at 2 centers by our team since November 1975. The 1349 male and 494 female patients had an overall mean age of 31.5±11.2 years; (range, 3-66). Grafts were obtained from a living-related donor in 1406 (76.29%) or a deceased donor in the remaining 437 (23.71%). The mean donor age was 40.7±13.7 years (range, 2-76). Of 1843 transplants, multiple vascular anastomoses were performed in 155 cases (8.4%), including 130 involving renal arteries and 25 renal veins.

RESULTS

Forty-seven vascular complications (2.55%) were observed in 43 procedures (2.33%), most frequently renal artery stenosis (n=14). It was followed by allograft renal artery kinking (n=7), renal vein kinking (n=7), renal artery thrombosis (n=5), renal vein laceration (n=4), renal artery laceration (n=3), renal vein thrombosis (n=2), renal artery disruption (n=2), renal and iliac vein obstructions owing to pressure from a lymphocele (n=1), renal artery and vein obstruction owing to pressure from a hematoma (n=1), or an arteriovenous fistula after percutaneous graft biopsy (n=1). Fifteen of these 47 complications were treated by interventional radiologic procedures.

CONCLUSION

The vascular complication rates in our patients were somewhat lower than those reported in the literature. A thorough understanding of how complications impair allograft function and survival is essential for adequate treatment. Interventional radiology is invaluable in the postoperative management of transplant-related complications.

Transcatheter renal artery embolization: clinical applications and techniques

Renal artery embolization is a minimally invasive procedure that is increasingly being used for treatment of a wide range of conditions. The main indications for renal artery embolization include (1) prenephrectomy and preradiofrequency ablation infarction of renal tumors, (2) management of renal angiomyolipomas, (3) palliations of unresectable renal malignancy, (4) renal hemorrhage (life-threatening or chronic debilitating hematuria), (5) arteriovenous fistulas, (6) vascular malformations, (7) renal artery aneurysms and pseudoaneurysms, and other less common indications, such as severe hydronephrosis and hypertension. A variety of embolic materials are available, such as metal coils, sclerosants (glue, Onyx, absolute ethanol, lipiodol), and particulate embolic agents (polyvinyl alcohol particles and embospheres). Selection of the appropriate agent depends on the clinical application, technical and clinical endpoints, as well as the pathology lesion(s) targeted. Renal artery embolization can be performed alone or in combination with remodeling techniques, stent-grafting, and balloon- or stent-assisted coiling in more complicated cases. The procedure is generally regarded as safe and effective for diverse applications and is considered as an evolving area in the field of endoluminal therapy.

Late renal vein thrombosis associated with recurrence of membranous nephropathy in a renal allograft: a case report

Allograft renal vein thrombosis (RVT) is an uncommon but potentially catastrophic complication. Although it usually occurs in the early posttransplant period and is associated with surgical complications or vascular rejection, it may develop later, when it is generally related with a hypercoagulable state. Typical clinical presentation is sudden oligoanuric acute renal failure, and hematuria, with a painful and swollen renal allograft. Confirmation of the diagnosis requires Doppler ultrasound and computed tomography. Herein we have reported a successfully treated case of late RVT that developed in an allograft with recurrent membranous nephropathy associated with the nephrotic syndrome. The patient fully recovered renal graft function a few days after presentation, which was related to anticoagulant therapy. We demonstrated complete recanalization of the venous thrombosis.