Post-transplant renal artery stenosis: impact of therapy on long-term kidney function and blood pressure control

Renal Artery Stenosis in Living Donor Kidney Transplantation: A Rare Cause of "Flash Edema"

Transplant renal artery stenosis (TRAS) is a well-recognized vascular complication after kidney transplantation, with an incidence ranging from 1% to 23%. TRAS often presents with clinical features such as refractory hypertension, de novo hypertension, allograft dysfunction, and the presence of a bruit over the graft. A rare manifestation of TRAS is flash pulmonary edema. Here, we present a case of a 37-year-old male who received a living donor kidney. Four years after the transplant, he presented with acute kidney injury, hypertensive crisis, and flash pulmonary edema. Initially, methylprednisolone pulses were administered due to suspicion of acute rejection, which was later ruled out after a kidney graft biopsy. Computed tomography angiography showed findings suggesting stenosis or thrombus in the renal artery. The patient developed sudden acute pulmonary edema, requiring hemodialysis, with notable clinical improvement. Subsequently, stent placement was performed without complications, resulting in the complete recovery of renal function and effective blood pressure control. The incidence of renal artery stenosis is higher in living donor kidney transplantation, mainly due to technical complexities during surgery. Acute presentations, such as flash edema, are exceptionally rare but can occur years after transplantation. Prompt intervention can lead to favorable outcomes.

Successful Endovascular Management of Resistant Hypertension Post Kidney Transplant: A Case Report

Rationale:

Transplant renal artery stenosis (TRAS) is a well-recognized and potentially reversible cause of resistant hypertension post transplantation and can affect 1% to 23% of recipients. Stenosis of the iliac segment proximal to the transplant renal artery (proximal TRAS) causing dysfunction of the transplanted kidney is less common with reported incidence of 2% to 3%. Presentation typically occurs between 3 months and 2 years post transplant but may happen at any time. Noninvasive investigations such as Doppler ultrasound, computed tomography (CT) angiogram, and magnetic resonance angiogram are useful in initial evaluation, but definitive diagnosis of hemodynamically significant stenosis often requires formal angiogram. Transplant renal artery stenosis should be suspected in any kidney transplant recipient with worsening hypertension and/or deterioration in kidney function which is otherwise unexplained. We present the case of a kidney transplant recipient with resistant hypertension and impaired graft function, secondary to severe impairment of graft blood flow from proximal iliac system occlusion.

Presenting concerns of the patient:

A 74-year-old female 15 years post live donor kidney transplant presented with graft dysfunction (serum Cr 229 μmol/L) and resistant hypertension, requiring use of 8 antihypertensive medications. On physical examination, blood pressure was 160/92 mm Hg with no tenderness over the renal graft in the right lower abdominal quadrant and no audible bruit in kidney allograft area.

Diagnosis:

Transplant Doppler ultrasound showed reversal of flow in the right external iliac artery suggestive of ipsilateral proximal iliac occlusion. Pre-procedure CT demonstrated severe atherosclerotic burden within the aorta and bilateral iliac systems. The anastomosed right renal artery appeared patent.

Interventions:

Conventional angiogram showed occlusion of the right common and proximal external iliac arteries with retrograde perfusion of the transplant kidney via the contralateral left iliac system and aorta. Subintimal recanalization of the right iliac system was performed with angioplasty and kissing stent placement at the aortic bifurcation with stents extending into the proximal right external iliac artery. Post deployment angiogram demonstrated renewed patency of the right iliac system, with restoration of antegrade perfusion to the transplant kidney.

Outcomes:

The patient’s blood pressure decreased significantly after the procedure, with improvement in graft function. After 6 months, the patient continued to have optimally controlled blood pressure (on 3 medications) and stable graft function (serum Cr 74 μmol/L).

Teaching points:

Our case describes proximal TRAS and the contribution of renal hypoperfusion to hypertension and impaired graft function, with the potential for reversibility.

Endovascular Treatment for Transplant Renal Artery Stenosis Improves the Short- and Long-Term Graft and Patient Outcomes

OBJECTIVES

Transplant renal artery stenosis is the commonest vascular complication after kidney transplant. This study aimed to evaluate the efficacy of endovascular treatment for patients with clinically significant transplant renal artery stenosis.

MATERIALS AND METHODS

Electronic patient records of kidney transplant recipients who received transplants from October 1, 2010, to July 31, 2021, at the Royal Liverpool University Hospital were retrospectively reviewedtoidentify thosewhounderwent endovascular treatment for transplant renal artery stenosis. Analysis of variance and paired sample t tests were respectively used to compare serum creatinine and the mean number of antihypertensive medications before and aftertreatment.

RESULTS

During the period of analysis, there were 1211 kidney transplant recipients, with 33 (2.72%) who received endovascular treatment for transplant renal artery stenosis. Mostofthesepatientsweremen(25/33), and the median age was 59 years (range, 27-83 y). The mean follow-up duration was 69.82 months. As primary treatment, 19/33 patients (57.6%) were treated with percutaneous balloon angioplasty and 14/33 (42.4%) received stents. Procedure-related complications occurred in 3 patients (9.1%; 2 had false aneurysms, 1 had renal artery dissection). Significant improvements in mean serum creatinine levels were shown up to 4 years after the procedure (P = .019). A significant difference in the mean number of antihypertensive drugs before and after treatment was noted in those who had resistant hypertension as a presentation for transplantrenal artery stenosis (P = .016). At the end of follow-up, 7 patients (21.1%) had graft failure, with 1 patient (3.0%) having graft failure as a direct consequence of transplant renal artery stenosis. There was no reported incidence of patient mortality.

CONCLUSIONS

Endovascular treatment for transplant renal artery stenosis provides a sustained improvement in graft function and a significant reduction in antihypertensive drug requirement.

Endovascular Treatment of Transplant Renal Artery Stenosis: A Systematic Review and Meta-analysis

OBJECTIVE

Endovascular treatment through either percutaneous transluminal angioplasty (PTA) alone or stenting has been previously used as a treatment for transplant renal artery stenosis (TRAS). This review aimed to investigate the results of endovascular treatment for renal artery stenosis in transplanted kidneys as compared with the outcomes of interventions, medical management, and graft survival in non-TRAS patients.

METHODS

A systematic review of PubMed, Google Scholar, Cochrane, and Scopus was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines in which studies that reported outcomes of the treatment of TRAS via the endoluminal approach were identified, and their results were meta-analyzed.

RESULTS

Fifty-four studies with a total of 1522 patients were included. A significant reduction of serum creatinine level was found, favoring the stenting group, with a mean difference of 0.68 mg/dL (95% confidence interval (CI), 0.17-1.19; Z=2.60, p=0.0009). Comparison of pre- and post-intervention values of any intervention revealed a significant decrease in overall serum creatinine level (0.65 mg/dL; 95% CI, 0.40-0.90; Z=5.09, p=0.00001), overall blood pressure, with a mean difference of 11.12 mmHg (95% CI, 7.29-14.95; Z=5.59, p=0.00001), mean difference in the use of medications (0.77; 95% CI, 0.29-1.24; p=0.002), and peak systolic velocity (190.05; 95% CI, 128.41-251.69; p<0.00001). The comparison of serum creatinine level between endovascular interventions and best medical therapy favored endovascular intervention, with a mean difference of 0.23 mg/dL (95% CI, 0.14-0.32; Z=5.07, p<0.00001). Graft survival was similar between the treated patients and those without TRAS (hazard ratio, 0.98; 95% CI, 0.75-1.28; p=0.091). The overall pooled success rate was 89%, and the overall complication rate was 10.4%, with the most prevalent complication being arterial dissection.

CONCLUSION

The endovascular treatment of TRAS improves graft preservation and renal function and hemodynamic parameters. PTA + stenting appears to be a more effective option to PTA alone in the stabilization of renal function, with additional benefits from decreased restenosis rates. Further high-quality studies could expand on these findings.

Intra-Arterial Hemodynamics to Guide the Percutaneous Treatment of a Difficult-to-Engage Transplant Renal Artery Stenosis

Transplant renal artery stenosis (TRAS) is the most frequent vascular complication after renal transplantation. TRAS is associated with resistant hypertension and allograft dysfunction, early diagnosis and either endovascular or surgical treatment is crucial to preserve graft function. Noninvasive imaging can usually detect the underlying stenosis. In this report we present a novel technique for successful angioplasty and stent deployment in a difficult-to-engage transplant-renal artery.

Renal Transplant Artery Inflow Stenosis Treated with Femorofemoral Bypass

In this case report we describe a novel and successful revascularization approach in instances of allograft and distal limb ischemia after kidney transplantation. Stenosis proximal to transplant renal artery anastomoses is a complication leading to allograft dysfunction and/or loss. We present a femorofemoral bypass graft with ringed polytetrafluoroethylene (PTFE). In this occasion, revascularization was achieved by a backflow mechanism. The approach described achieved its goal of revascularizing the allograft as well as the distal extremity, with both short- and long-term successful outcomes. Benefits of this approach when compared with re-implantation or procedures directly involving the transplant renal artery include minimization of ischemic time, no need to repair the stenosis, anastomoses with vessels of greater diameter, no need to perfuse the kidney, no need to take down the renal artery anastomosis, no need to dissect the transplanted kidney, and no further lower extremity ischemia. This approach does not require any proximal temporary inflow occlusion (as seen with stent placement) or clamping of the arterial inflow to the kidney. This procedure was completed without having to infuse any preservation fluid into the kidney.

MRI for diagnosis of post-renal transplant complications: current state-of-the-art and future perspectives

Kidney transplantation has developed into a widespread procedure to treat end stage renal failure, with transplantation results improving over the years. Postoperative complications have decreased over the past decades, but are still an important cause of morbidity and mortality. Early accurate diagnosis and treatment is the key to prevent renal allograft impairment or even graft loss. Ideally, a diagnostic tool should be able to detect post-transplant renal dysfunction, differentiate between the different causes and monitor renal function during and after therapeutic interventions. Non-invasive imaging modalities for diagnostic purposes show promising results. Magnetic resonance imaging (MRI) techniques have a number of advantages, such as the lack of ionizing radiation and the possibility to obtain relevant tissue information without contrast, reducing the risk of contrast-induced nephrotoxicity. However, most techniques still lack the specificity to distinguish different types of parenchymal diseases. Despite some promising outcomes, MRI is still barely used in the post-transplantation diagnostic process. The aim of this review is to survey the current literature on the relevance and clinical applicability of diagnostic MRI modalities for the detection of various types of complications after kidney transplantation.

Carbon Dioxide Angiography in the Treatment of Transplant Renal Artery Stenosis

BACKGROUND

Transplant renal artery stenosis (TRAS) is a serious complication associated with graft loss. Selective carbon dioxide angiography allows for effective diagnosis and therapy with the use of minimal to no contrast agent. This study sought to evaluate the efficacy of the adjunctive use of carbon dioxide angiography in the treatment of TRAS.

METHODS

Patients undergoing endovascular therapy (percutaneous transluminal angioplasty with or without stent) for TRAS between the years 2012 and 2017 at a single tertiary care academic medical center were studied. Outcomes of interest included technical success, postoperative glomerular filtration rate, and renal ultrasound hemodynamic parameters.

RESULTS

Of the 37 patients who underwent angiography for TRAS during the study period, 34 underwent a therapeutic intervention. Of those, 24 patients (70.6%) underwent adjunctive carbon dioxide angiography versus 10 patients (29.4%) who underwent standard contrast angiography. Baseline characteristics between the carbon dioxide angiography and traditional angiography groups were similar. Patients undergoing carbon dioxide angiography received significantly less contrast agent than patients undergoing traditional angiography [9.5 mL (IQR 2-19.5) versus 19.5 mL (IQR 15-30), P = 0.03)] and maintained equivalent technical success rates (92.2% vs. 91.7%, P = 0.9).

CONCLUSIONS

The adjunctive use of carbon dioxide angiography allows for significantly less contrast administration compared with standard angiography while achieving an equivalent rate of technical success. Selective carbon dioxide angiography should be considered a first-line modality for patients with TRAS in need of endovascular therapy.

Percutaneous transluminal angioplasty alone versus stent placement for the treatment of transplant renal artery stenosis

PURPOSE

The purposes of this retrospective study were to assess the efficacy of endovascular techniques for the treatment of transplant renal artery stenosis (TRAS) by analyzing technical and clinical success and to compare the results of percutaneous transluminal angioplasty (PTA) alone to those of stenting.

MATERIALS AND METHODS

A retrospective analysis was conducted on 31 patients who underwent endovascular treatment for TRAS between January 2012 and December 2017. There were 23 men and 8 women with a mean age of 60.5±14 (SD) years (range: 24-81 years). Ten patients (10/31; 32%; 8 men, 2 women; median age, 63 years) were treated with PTA alone and 21/31 (68%; 15 men, 6 women; median age, 65 years) with metallic stent placement. Several variables including serum creatinine level, glomerular filtration rate, arterial blood pressure value, antihypertensive medication obtained before and after treatment were compared. Technical success was assessed for each procedure. Clinical success was defined as a 15% drop in serum creatinine level, a decrease greater than 15% in mean blood pressure values or a decrease greater than 10% in mean blood pressure values with a reduction in the number of antihypertensive drugs needed for hypertension control.

RESULTS

Technical success was obtained in all patients [31/31; 100%; 95% confidence interval (CI): 89-100%] and clinical success in 27/31 patients (87%; 95%CI: 71-95%). Four patients (4/31; 13%; 95%CI: 5-29%) underwent repeat endovascular intervention. Mean serum creatinine level and mean arterial blood pressure values were significantly lower after treatment (177.4 and 93.8μmol/l, respectively) compared to before treatment (319.4 and 106.7μmol/l, respectively) in the stent group but not in the group treated with PTA alone (P=0.0012 and P=0.002, respectively).

CONCLUSION

The endovascular approach is safe and effective in the management of TRAS and stenting, depending on the morphology of the stenosis, should be the treatment of choice when possible.

Risk factors for transplant renal artery stenosis after live donor transplantation

Background

Renal transplant surgeons are making increasing use of live donor kidneys with multiple renal arteries. This study aimed to identify independent risk factors for the development of transplant renal artery stenosis (TRAS) in the modern era of complex arterial reconstruction for multiple vessels.

Methods

Multivariable logistic regression analysis with a stepwise variable deletion model was used to identify risk factors for the development of TRAS in a consecutive series of live donor kidney transplants.

Results

Of 506 kidney transplants, 19 (3·8 per cent) had evidence of significant TRAS on CT angiography. Functional TRAS, defined by improvement in BP control or renal function after correction of a stenosis by angioplasty, occurred in 13 of 506 patients (2·6 per cent). Independent risk factors for TRAS were: use of an explanted internal iliac artery graft from the recipient (odds ratio (OR) 4·95; P = 0·020) and total ischaemia time (OR 1·82; P = 0·010). TRAS was associated with a lower 5-year allograft survival rate (79 versus 88·7 per cent; P = 0·020) but only one graft loss was attributed directly to TRAS. The 5-year allograft survival rate after internal iliac artery grafting was 86 per cent.

Conclusion

Although use of an internal iliac artery graft is an independent risk factor for TRAS after live donor kidney transplantation, this technique is still a useful option for complex arterial reconstruction.

Endovascular Treatment of Transplant Renal Artery Stenosis: Evaluation of Postoperative Outcomes and Risk Factors for Recurrence

Angioplasty with or without stenting has become a well-established procedure to treat transplant renal artery stenosis (TRAS). We evaluated our experience on postoperative outcomes following the intervention and identified potential predictive factors of TRAS recurrence. Consecutive patients who underwent endovascular treatment of TRAS were retrospectively reviewed. The study end points were the technical success, 30-day postoperative complications, and the estimated glomerular filtration rate (eGFR). Thirty-two patients underwent endovascular treatment for TRAS. The technical success rate was 96.6%. Complications were observed for 7 (21.9%) patients: 4 had a dissection, 2 a pseudoaneurysm, and 1 (3.1%) patient developed an acute pulmonary edema. The mean eGFR significantly increased at 7 days, 3 months, and 6 months postintervention (43.1, 44.9, and 44.3 vs 33.9 mL/min/1.73 m2 preoperatively, P < .05). The TRAS recurrence was observed in 7 (21.9%) patients. These patients had significantly higher preoperative peak systolic velocity and systolic rise time (5 vs 4 m/s, P = .0383 and 103 vs 80 milliseconds, P = .0148, respectively). Endovascular treatment of TRAS is associated with high technical success and significant improvement in renal function. Further studies are required to confirm predictive factors of TRAS recurrence following endovascular treatment.

Evaluation of the efficacy and safety of endovascular management for transplant renal artery stenosis

OBJECTIVES

To evaluate the safety and efficacy of endovascular intervention with angioplasty and stent placement in patients with transplant renal artery stenosis.

METHODS

All patients diagnosed with transplant renal artery stenosis and graft dysfunction or resistant systemic hypertension who underwent endovascular treatment with stenting from February 2011 to April 2016 were included in this study. The primary endpoint was clinical success, and the secondary endpoints were technical success, complication rate and stent patency.

RESULTS

Twenty-four patients with transplant renal artery stenosis underwent endovascular treatment, and three of them required reinterventions, resulting in a total of 27 procedures. The clinical success rate was 100%. All graft dysfunction patients showed decreased serum creatinine levels and improved estimated glomerular filtration rates and creatinine levels. Patients with high blood pressure also showed improved control of systemic blood pressure and decreased use of antihypertensive drugs. The technical success rate of the procedure was 97%. Primary patency and assisted primary patency rates at one year were 90.5% and 100%, respectively. The mean follow-up time of patients was 794.04 days after angioplasty.

CONCLUSION

Angioplasty with stent placement for the treatment of transplant renal artery stenosis is a safe and effective technique with good results in both the short and long term.

Thoracic endovascular aortic repair for type B aortic dissection after renal transplantation

Thoracic endovascular repair (TEVAR) is an effective treatment for type B aortic dissection (TBAD). Here, we evaluated the early-midterm effectiveness and safety of TEVAR for treating TBAD patients after renal transplantation. Six patients with TBAD treated with TEVAR after renal transplantation were recruited between February 2012 and December 2016. They were then followed up with clinical examinations and computed tomography angiography (CTA). TEVAR was successfully performed in all patients (100%), and the primary tear sites were well covered by stents with or without coverage of the left subclavian artery. No severe complications occurred in any patient during perioperative period. The one-year survival rate was 100%, one patient died of renal graft failure and heart failure four years after TEVAR; the remaining five patients (83.3%) survived and exhibited no severe complications. Our findings show that TEVAR provides satisfactory short-midterm results for TBAD patients after renal transplantation. Moreover, our experience shows that it need relative longer proximal landing zone to prevent the endoleak and recurrence. However, regular hematodialysis, long-term immunosuppressive therapy, and blood pressure control remain crucial factors to prolong survival. Long-term follow-up studies are needed to evaluate the long-term prognosis in these patients.

Combined Percutaneous Transrenal and Transfemoral Endovascular Recanalization and Angioplastic Reconstruction of a Disrupted Transplant Renal Artery Stent: A Novel Salvage Technique

Renal artery stenosis is the most common vascular complication following renal transplantation. Percutaneous endovascular transluminal angioplasty with stenting is the treatment of choice for clinically significant renal artery stenosis. The authors present a case describing a novel combined transrenal parenchyma and transfemoral approach to repairing a disrupted transplant renal artery stent. The patient's allograft renal artery stenosis was initially managed via the standard percutaneous approach, but during follow-up the stent became disrupted and crushed, causing partial occlusion of the renal artery. This was manifested by persistently elevated serum creatinine values, lower extremity edema, and four-medication hypertension. After a failed traditional percutaneous transfemoral attempt, the authors were able to successfully access the renal arterial system via a combined transrenal and transfemoral approach, using an upper-pole artery through the renal parenchyma. This transrenal approach used a 3 Fr system, allowing the authors to get a wire across the stent, which they were previously unable to do. With wire access, they performed a balloon angioplastic reconstruction to restore the stent's patency, resulting in a reduction in serum creatinine, lower extremity edema, and blood pressure. This technique avoided a potentially difficult reoperative repair without immediate complication and provides a method for vascular access to the renal arterial system in select patients.

Transplant renal artery stenosis: The impact of endovascular management and their outcomes

Introduction:

Transplant renal artery stenosis (TRAS) is a well-known vascular complication of renal transplantation. The aim of this analysis was to assess the short and midterm outcomes of endovascular therapy to salvage transplant kidney.

Methods:

We retrospectively analyzed our transplant database from 2000 to 2015. Percutaneous transluminal angioplasty/stenting was done in 24 patients (22 men and two women) with significant TRAS. The mean age was 59 ± 12 years. The parameters analyzed were: Technical success, pre- and post-treatment serum creatinine and number of antihypertensive drugs before and after treatment and vessel patency on Doppler ultrasonography at 3 and 6 months.

Results:

Overall incidence of TRAS in this study was 5.06%. Incidence of TRAS following live donor transplantation was 4.68% while that in deceased donors was 11.5%. Technical success was 100%. There were no periprocedural deaths. Renal function was improved from 2.32 ± 0.5 mg/dL to 1.72 ± 0.3 mg/dL (P < 0.001) and number of antihypertensive medications after the procedure was reduced from 2.9 ± 0.7 to 2 ± 0.6 (P < 0.001) at 6 months follow-up. One patient developed restenosis within 5 months (4.2%). Clinical success at 6 months follow-up was 79.2%.

Conclusions:

Endovascular treatment of TRAS has high technical success with minimal complications. It also provides satisfactory clinical success with improvement in overall transplant renal function and renovascular hypertension in early follow-up.

When is contrast-enhanced sonography preferable over conventional ultrasound combined with Doppler imaging in renal transplantation?

Conventional ultrasound in combination with colour Doppler imaging is still the standard diagnostic procedure for patients after renal transplantation. However, while conventional ultrasound in combination with Doppler imaging can diagnose renal artery stenosis and vein thrombosis, it is not possible to display subtle microvascular tissue perfusion, which is crucial for the evaluation of acute and chronic allograft dysfunctions. In contrast, real-time contrast-enhanced sonography (CES) uses gas-filled microbubbles not only to visualize but also to quantify renal blood flow and perfusion even in the small renal arterioles and capillaries. It is an easy to perform and non-invasive imaging technique that augments diagnostic capabilities in patients after renal transplantation. Specifically in the postoperative setting, CES has been shown to be superior to conventional ultrasound in combination with Doppler imaging in uncovering even subtle microvascular disturbances in the allograft perfusion. In addition, quantitative perfusion parameters derived from CES show predictive capability regarding long-term kidney function.

Successful endovascular treatment of transplant intrarenal artery stenosis in renal transplant recipients: Two case reports

Transplant renal artery stenosis (TRAS) is a relatively rare complication after renal transplantation. The site of the surgical anastomosis is most commonly involved, but sites both proximal and distal to the anastomosis may occur, as well. Angioplasty is the gold standard for the treatment of the stenosis, especially for intrarenal lesions. We report two cases of intrarenal TRAS and successful management with angioplasty without stent placement. Both patients were male, 44 and 55 years old respectively, and they presented with elevated blood pressure or serum creatinine within three months after transplantation. Subsequently, they have undergone angioplasty balloon dilatation with normalization of blood pressure and serum creatinine returning to baseline level. Percutaneous transluminal balloon renal angioplasty is a safe and effective method for the treatment of the intrarenal TRAS.

Tailoring the endovascular management of transplant renal artery stenosis

In this study we analyze the different types of endovascular interventions (EVIs) in de novo transplant renal artery stenosis (TRAS) and its anatomical subtypes to examine any variation in recovery of allograft function, blood pressure control, EVI patency and allograft survival with respect to EVI type (DES: drug-eluting stent, BMS: bare-metal stent, PTA: percutaneous transluminal angioplasty). Forty-five patients underwent a total of 50 primary EVIs (DES: 18, BMS: 26, PTA: 6). Patients were stratified according to medical co-morbidities, graft characteristics, biopsy results, clinical presentation and TRAS anatomic subtypes (anastomotic: 26, postanastomotic: 17, bend-kink: 2). There was significant improvement in allograft function and mean arterial blood pressure (MAP) control across all interventions (pre-EVI-creatinine [CR]: 2.8 ± 1.4, post-EVI-Cr: 2.1 ± 0.7, p < 0.001; pre-EVI-MAP: 117 ± 16, post-EVI-MAP: 112 ± 17, p = 0.03) with no significant difference among EVI types. There was no significant difference in allograft survival with respect to EVI type. Patency was significantly higher in EVIs performed with DES and BMS compared to PTA (p = 0.001). In the postanastomotic TRAS subtype, patency rates were significantly higher in DES compared to BMS (p = 0.012) in vessels of comparable reference diameter (≤5 mm).

Hypertension, living kidney donors, and transplantation: where are we today?

Hypertension is a prevalent problem in kidney transplant recipients that is known to be a "traditional" risk factor for atherosclerotic cardiovascular disease leading to premature allograft failure and death. Donor, peritransplant, and recipient factors affect hypertension risk. Blood pressure control after transplantation is inversely associated with glomerular filtration rate (GFR). Calcineurin inhibitors, the most commonly used class of immunosuppressives, cause endothelial dysfunction, increase vascular tone, and sodium retention via the renin-angiotensin-aldosterone system resulting in systemic hypertension. Steroid withdrawal seems to have little impact on blood pressure control. Newer agents like belatacept appear to be associated with less hypertension. Transplant renal artery stenosis is an important, potentially treatable cause of hypertension. Dihydropyridine calcium channel blockers mitigate calcineurin inhibitor nephrotoxicity and may be associated with improved estimated GFR. Angiotensin-converting enzyme inhibitors and angiotensin receptor blockers are not recommended in the first 3 to 6 months given their effects on reduced estimated GFR, anemia, and hyperkalemia. The use of ß-blockers may be associated with improved patient survival, even for patients without cardiovascular disease. Living donation may increase blood pressure by 5 mm Hg or more. Some transplant centers accept Caucasian living donors with well-controlled hypertension on a single agent if they agree to close follow-up.

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.

Vascular and haemorrhagic complications of adult and paediatric live-donor renal transplantation: A single-centre study with a long-term follow-up

Objectives

To compare the haemorrhagic and vascular complications between paediatric and adult renal transplant recipients with a long-term follow-up.

Patients and methods

Between March 1976 and December 2006, in all, 1865 live-donor renal transplants were carried out. Patients were stratified according to their ages into two groups; paediatric (⩽18 years; 259) and adult (>18 years; 1606). Variables assessed included incidence, risk factors, management and sequelae of vascular and haemorrhagic complications. The effect of these complications on patient and graft survival was compared.

Results

Haemorrhage requiring active intervention (percutaneous drainage or surgical exploration) was reported in seven children (2.7%) and 29 adults (1.8%), while thrombotic or stenotic complications were recorded in two children (0.77%) and 19 adults (1.18%; P < 0.05). Female gender, delayed onset of diuresis and acute tubular necrosis were significant predictors of vascular complications on univariate analysis, but none remained significant on multivariate analysis. In adults, vascular complications had a significant negative effect on mean (SD) 10-year graft survival compared to patients with no complications, at 19.8 (7.63)% vs. 55.7 (1.66)% (P = 0.01). Children who developed vascular complications had a significantly higher 5- and 10-year graft survival rate than adults (P = 0.01).

Conclusion

The incidence of vascular complications is comparable in paediatric and adult transplants. Vascular complications had a significant negative influence on graft survival in adult recipients. Children who developed vascular complications appear to tolerate its effects and have a better graft survival than have adults.

The use of drug-eluting stents in the management of transplant renal artery stenosis

Transplant renal artery stenosis (TRAS) is a common occurrence following kidney transplantation with an incidence rate ranging from 6% to 23%. A single-center retrospective study was conducted to examine the use of drug-eluting stents (DES) in eligible patients with hemodynamically significant TRAS. Between March 2008 and January 2011, 12 patients were diagnosed with TRAS with reference vessel diameter measuring <5 mm and underwent endovascular intervention (EVI) with DES placement. TRAS was detected within the first year posttransplantation in a majority of these patients (83%) and manifested as hypertension (100%), allograft dysfunction (100%) and edema (58%). Procedural success rate was 100%. Patients were followed for a mean period of 16 ± 10 months. Blood pressure improved from a mean of 156/82 to 138/73 mmHg at the end of the follow-up period. In 11/12 patients, serum creatinine improved from 3.1 ± 1.3 mg/dL to 2.3 ± 0.5 mg/dL at the end of the follow-up period. TRAS of early onset is readily amenable to EVI with stent placement resulting in improvement in blood pressure control and allograft function.

Detection and treatment of transplant renal artery stenosis

Purpose:

To assess the effects of transplant renal artery stenosis (TRAS) on blood pressure, renal function, and graft survival. To assess the usefulness of Doppler in predicting the clinical significance of TRAS and also to identify the predictive factors in Doppler that correlated with clinical features of TRAS.

Materials and Methods:

A prospective study was done on consecutive renal allograft recipients at Christian Medical College, over a period of 66 months from January 2002. All recipients underwent Doppler ultrasound (DUS) evaluation on the fifth post-operative day. Subsequent evaluation was done if the patients had any clinical or biochemical suspicion of TRAS. Angiogram was done in case of a high index of suspicion of significant stenosis or before angioplasty and stenting. The clinical and radiological outcomes of the patients with symptomatic or asymptomatic TRAS were analyzed.

Results:

Five hundred and forty three consecutive renal allograft recipients were analyzed, of whom, 43 were found to have TRAS. Nine recipients (21%) were detected to have TRAS on first evaluation. All had a high peak systolic velocities (PSV) recorded while 25 of them had other associated features. Patients with only high PSV required no further intervention and were followed up. They had a pretransplant mean arterial pressure (MAP) of 107.83 mmHg (SD = 13.32), ranging from 90 to 133 mm Hg and a posttransplant MAP of 106.56 mmHg (SD =16.51), ranging from 83 to 150 mm Hg. Their mean nadir serum creatinine was 1.16 mg% (SD = 0.24), at detection was 1.6 mg% (SD = 1.84) and at 6 months follow-up was 1.26 mg% (SD=0.52). Of the remaining 25 patients with other associated Doppler abnormalities, 11 required further intervention in the form of re-exploration in 2, angioplasty in 3 and stenting in 6 patients. One patient in the group of patients intervened, expired in the immediate post-operative period due to overwhelming urosepsis and consumption coagulopathy. The mean creatinine clearance (Cockroft-Gault method) in this group of remaining 10 patients, before and after intervention was 44.75 ml/min (SD=17.85) and 68.96 ml/min (SD = 10.56), respectively, with a mean increase by 24.21 ml/min (P=0.000). The mean arterial pressure before and after intervention in this group were 132.80 mm Hg (SD = 13.22) and 102 mm Hg (SD = 10.55), with a decline in the MAP by 30.80 mmHg (P=0.017). The haemoglobin levels also increased from 11.72 (SD=2.13) to 12.48 gm% (SD = 1.75), with a mean increase by 0.76 gm% (P=0.05).

Conclusions:

Patients with isolated high PSV do not have a significant alteration of blood pressure or allograft function and required no intervention. Although high PSV with associated Doppler anomalies are more suggestive of significant TRAS, the decision regarding surgical intervention is largely based on clinical assessment.

Management of transplant renal artery stenosis

Transplant renal artery stenosis is the most frequent vascular complication of transplantation. Early detection and correction reduce patients' morbidity and allograft dysfunction. Although noninvasive imaging can detect an underlying stenosis, angiography with subsequent angioplasty or stenting, or both, provides definitive diagnosis and treatment. With the introduction of alternative contrast agents and newer catheter and stent technology, these procedures can be performed safely with little risk of contrast-induced nephropathy or allograft loss.

Hypertension after kidney transplant

Hypertension in kidney transplant recipients is a major "traditional" risk factor for atherosclerotic cardiovascular disease. Importantly, atherosclerotic cardiovascular disease is the leading cause of premature death and a major factor in death-censored graft failure in transplant recipients. The blood pressure achieved after transplant is related inversely to postoperative glomerular filtration rate (GFR), with many patients experiencing a significant improvement in blood pressure control with fewer medications within months of surgery. However, the benefits of improved GFR and fluid status may be affected by the immunosuppression regimen. Immunosuppressive agents affect hypertension through a variety of mechanisms, including catechol- and endothelin-induced vasoconstriction, abrogation of nitric oxide-induced vasodilatation, and sodium retention. Most notable is the role of calcineurin inhibitors in promoting hypertension, cyclosporine more so than tacrolimus. Additionally, the combination of calcineurin- and mammalian target of rapamycin (mTOR)-inhibitor therapy is synergistically nephrotoxic and promotes hypertension, whereas steroid withdrawal and minimization strategies seem to have little or no impact on hypertension. Other important causes of hypertension after transplant, beyond a progressive decrease in GFR, include transplant renal artery stenosis and sequelae of antibody-mediated rejection. Calcium channel blockers may be the most useful medication for mitigating calcineurin inhibitor-induced vasoconstriction, and use of such agents may be associated with improvements in GFR. Use of inhibitors of the renin-angiotensin system, such as angiotensin-converting enzyme inhibitors and angiotensin receptor blockers, remains an attractive strategy for many transplant recipients, although some recipients may have significant adverse effects associated with these medications, including decreased GFR, hyperkalemia, and anemia. In conclusion, hypertension control affects both patient and long-term transplant survival, and its best management requires careful analysis of causes and close monitoring of therapies.

Salvage of hyperacute renal transplant hypoperfusion with stent placement: a case report

The authors report on a patient who underwent renal artery stent placement 6 hours after transplantation due to acute hypoperfusion of the transplant, which was diagnosed with intraoperative Doppler ultrasonography. Extensive atherosclerotic disease of the cadaveric transplant renal artery necessitated endarterectomy before creation of the anastomosis, and no further surgical options were considered feasible by the transplant surgeon. Six hours after the transplantation, percutaneous transluminal renal angioplasty and stent placement were performed, resulting in restoration of normal arterial flow and rescue of allograft function.

Restoration of failed renal graft function after successful angioplasty of pressure-resistant renal artery stenosis using a cutting balloon: a case report

This study is the report of a 37-year-old male with a transplanted kidney from a 3.5-year-old donor: the graft had two arteries transplanted with an aortic patch to an external iliac artery. Four months after transplantation, the graft function deteriorated, together with the development of hypertension. Stenosis of both graft arteries was detected and the patient was referred for angioplasty. The angiographic result was suboptimal, nevertheless, the graft function improved and was more or less stable (serum creatinine, 160-200 micromol/l) for 4 years, along with persistently difficult-to-control hypertension. Five years after transplantation, the graft function deteriorated again and severe graft artery restenosis was detected. The restenosis did not respond to dilatation, graft function failed, hypertension decompensated, and left ventricular failure developed. The patient required dialysis. A cutting balloon angioplasty opened the artery, and kidney function was restored after a few days: the serum creatinine level dropped to 140-160 micromol/l, and the glomerular filtration rate (creatinine clearance) to 0.65 ml/min/1.73 m(2). The graft function has now been stable for more than 2 years, however, the hypertension is still difficult to control.

Long-term follow-up of renal transplant patients with renal artery stenosis treated by percutaneous angioplasty

PURPOSE OF THE STUDY

To evaluate if renal angioplasty (PTRA) in patients with transplanted kidney and renal artery stenosis (TRAS) can have long-term effect on hypertension and renal function.

MATERIALS AND METHODS

Within a 24-year time period, 58 PTRAs in 55 adults (three times Re-PTRA) with transplanted kidney were performed. The group included 34 males and 21 females, average age 41+/-10.6 (18-72) years. After exclusion of 7 technical failures, 51 PTRAs were followed at 1 week, 6 months and 1-3 years after PTRA. Hypertension improvement was defined as mean arterial pressure (MAP) decrease of at least 15% from the pre-PTRA value. Graft function was evaluated by serum creatinine (Scr) and creatinine clearance (Ccr) levels, and the improvement was defined as a 20% change. Clinical FU was 3 years.

RESULTS

PTRA technical success was 88.4%. In 51 kidney recipients at the end of FU, blood pressure improved in 65.2% of patients (MAP decreased from 123+/-13.1 to 107+/-12.1 mmHg), but no patient remained normotensive medication free. Graft function improved in 44.8% of patients and was stabilized in 20.7% of them (average Ccr before PTRA: 0.48+/-0.29, after PTRA: 0.78+/-47 ml/s). PTRA complications were observed in 25.5% of procedures, most often with no clinical sequel. Thirty days mortality was 1.8% (one patient).

CONCLUSIONS

PTRA results in kidney recipients are valuable mainly in preserving graft function.

Vascular complication and Doppler ultrasonographic finding after renal transplantation

OBJECTIVES

Vascular complications are common after renal transplantation. In this study we correlated Doppler sonographic indices and transplant kidney function.

METHODS

We reviewed data on 244 renal transplant patients. Doppler ultrasonographic evaluation was performed during the first 2 weeks after renal transplantation. We determined resistive index (RI) and pulsatility index (PI) in the interlobar arteries and thrombosis of renal and lower limb veins. Serum creatinine (Cr) and cyclosporine levels were evaluated prior to sonographic assessment.

RESULTS

The mean age of the 142 male and 102 female patients was 36.31 +/- 3.30 years. Prevalence of real artery stenosis was 9.5%. In these patients the mean serum Cr level (2.21 +/- 1.83 mg/dL) was significantly higher than among patients with patent renovascular tributary (1.49 +/- 1.00 mg/dL; P=.03). RI and PI were also significantly correlated with serum Cr(P=.05 and .001, respectively). There was no relationship between cyclosporine level or panel-reactive antibody with RI and PI. Retransplant patients showed higher RI than first renal allograft recipients (0.72 +/- 0.16 vs 0.63 +/- 0.11; P=.006). Serum Cr level was higher among renal allograft recipients with Doppler evidence of thrombosis of the lower limb veins (3.1 +/- 0.98 mg/dL versus 1.56 +/- 1.13 mg/dL; P=.04).

CONCLUSIONS

RI and PI are two valuable Doppler ultrasonographic markers to determine renal allograft function and related vascular complications.

Hypertension After Renal Transplant

Hypertension is common after renal transplant and is associated with adverse graft and patient outcomes. A thorough understanding of the unique factors that operate in renal transplant recipients is essential for the proper evaluation and management of this disorder. In this review, the authors outline the pathogenesis, diagnostic workup, and treatment of hypertension after renal transplant.

Current management of transplant renal artery stenosis: clinical utility of duplex Doppler ultrasonography

OBJECTIVES

To perform a retrospective study to determine the clinical utility of Doppler ultrasonography (DUS) and to determine its role in the management of transplant renal artery stenosis (TRAS).

METHODS

Patients undergoing DUS between January 1998 and January 2001 for clinical suspicion of TRAS were included in the study. A total of 51 patients were divided into two groups according to the peak systolic velocity. Additional management was based on the clinical and DUS findings and their congruence. Patients were followed up and their outcome was analyzed.

RESULTS

Of the 51 patients who entered the study, 26 were in the low probability group (LPG) and 25 in the high probability group (HPG). Nine patients in the LPG underwent additional investigations; eight underwent magnetic resonance angiography and one angiography. Of these 9 patients, 6 had stenosis, 4 of whom required angiography. In total, 5 patients from the LPG underwent angioplasty, and 4 of them had stenosis (1 with TRAS, 2 with common iliac artery stenosis, and 1 with renal artery ostial stenosis). Three patients underwent angioplasty and 2 of them improved. In the HPG, 20 of 25 patients underwent additional investigations, including magnetic resonance angiography in 12 and angiography in 8, with stenosis in 15 patients. Of the HPG, 13 of 25 patients underwent angiography, with 10 requiring angioplasty--8 for TRAS and 2 for adjacent renal artery stenosis, with improvement in 8 patients. Congruent clinical and DUS findings were highly predictive of significant stenosis more amenable to improvement.

CONCLUSIONS

The results of our study have shown that high-probability DUS and congruent clinical findings are likely to identify a significant stenosis that is amenable to treatment. Low-probability DUS findings do not eliminate the possibility of stenosis, but intervention in this group is less likely to result in improvement.

Transplant renal artery stenosis: outcome after percutaneous intervention

PURPOSE

To assess the outcome of percutaneous transluminal angioplasty (PTA) and stent placement as the primary treatment for transplant renal artery stenosis (TRAS).

MATERIALS AND METHODS

A retrospective review of PTA and stent placement procedures performed for TRAS from April 1997 to July 2003 was conducted. Reviewed parameters included technical success, date of transplantation, dates of percutaneous intervention, mean arterial blood pressure, number of blood pressure medications, and serum creatinine level before and after intervention. Twenty-one interventions were performed in 18 allografts. The primary clinical indication for imaging and treatment was increased creatinine level in 12 allografts and hypertension in six allografts. Patency rates were estimated with use of the Kaplan-Meier method.

RESULTS

The technical success rate of PTA/stent placement was 100% and the clinical success rate was 94% (17 of 18 allografts). Thirteen interventions involved PTA alone, with eight combined PTA and stent insertions. The mean preintervention serum creatinine level among 12 allografts presenting with elevated creatinine levels was 2.8 mg/dL +/- 1.4 (SD), compared with a 1-month postintervention mean of 2.2 mg/dL +/- 0.7 (P = .03). Of six allografts that presented with hypertension, significant improvement was seen between the preintervention and 1-month postintervention mean systolic (174 mm Hg vs 135 mm Hg, P = .003) and diastolic (99 mm Hg vs 82 mm Hg, P = .02) pressures. These patients required a mean of 2.3 medications for blood pressure control before intervention, compared with a mean of 1.0 medications at 1 month after intervention (P = .002). Primary patency rates at 3, 6, and 12 months (+/-95% CI) were 94% +/- 6%, 72% +/- 12%, and 72% +/- 12%, respectively. Secondary patency rates at 3, 6, and 12 months (+/-95 CI) were 100%, 85% +/- 10%, and 85% +/- 10%, respectively. Mean follow-up time was 27 months. Of the eight allografts that underwent stent placement, all eight remained patent at last follow-up (mean, 18.3 months +/- 9.2). One major complication of a puncture site pseudoaneurysm occurred (5%).

CONCLUSION

Primary treatment of TRAS with PTA with or without stent placement has good intermediate-term patency and is associated with significant early improvement in blood pressure and creatinine level.

Percutaneous treatment of transplant renal artery stenosis in children

Percutaneous treatment of renal artery stenosis (RAS) is an accepted procedure and numerous reports have been published. However, experience with its use in RAS in the transplanted kidney in children is scarce. Since 1994 we have diagnosed RAS in seven children with the use of Doppler ultrasonography (US), confirming it with percutaneous angiography (PAG). In six of the seven patients percutaneous transluminal angioplasty (PTA) was performed. In one patient a metallic stent was placed due to the extension of the arterial lesion, and a second stent was placed in another child when a re-stenosis was diagnosed 1 month after the PTA. All patients presented with hypertension (de novo or 30% increase over previous values). After ruling out acute rejection, calcineurin inhibitor toxicity, and urinary obstruction, US was performed and, when an increase in arterial flux velocity was registered, PAG was also performed. Six children showed an increase in serum creatinine (Cr) and proteinuria. Blood pressure decreased after the procedure and Cr returned to previous levels in all children. One of the grafts was lost due to chronic transplant rejection 7 years later. The other children have a functioning kidney. Although this is a small group of patients, the consistently good results and the lack of reported experience prompted us to communicate our preliminary observation.

Histopathological study of renal transplant artery stenosis: role of rejection and cold ischaemia time in the pathogenesis of intimal hyperplasia in an arterial allograft

INTRODUCTION

Intimal hyperplasia of renal allograft arteries is a cause of hypertension and graft loss and the predisposing factors are poorly understood. We performed a histopathological study focusing on cold ischaemia time and immunological factors and their effect on the donor artery.

METHODS

Primary renal artery branches were obtained from patients undergoing transplant nephrectomy for chronic rejection. Non-transplant patients undergoing nephrectomy served as controls. Clinical information including immunosuppression and rejection episodes, cold ischaemia time and graft survival were collected from the patients' charts. Collagen, smooth muscle cells, T cells, macrophages, and neutrophils were quantified using immunohistochemistry. The intima to media ratio was also calculated using imaging software. Statistical analysis was performed using linear regression and the Mann-Whitney test with P < 0.05 significant.

RESULTS

Nine transplant patients and five controls were included. All transplant patients received maximum immunosuppression according to clinical standards. The median number of acute rejection episodes was 1 (range 0-5). Cold ischaemia time was 24.3 +/- 9.6 h (mean +/- SD). Mean allograft longeviy was 87.4 +/- 72.9 months (mean +/- SD). The intima/media ratio in the transplant group was higher as compared with the control (P = 0.002). The same was true for intima collagen content (P = 0.001) and intima smooth muscle content (P = 0.036). Cold ischaemia time was 19.6 +/- 11.1 h (mean +/- SD) and did not correlate with intima/media ratio. Also the number of rejection episodes did not correlate with the intima/media ratio.

CONCLUSION

Intimal hyperplasia in the allograft artery has a multifactorial aetiology. We were not able to establish an association between intimal hyperplasia and acute rejection episodes or length of cold ischaemia time. It appears that immunosuppression does not prevent the development of intimal hyperplasia.

Iliac artery stenosis proximal to a kidney transplant: clinical findings, duplex-sonographic criteria, treatment, and outcome

BACKGROUND

Stenosis of the iliac segment proximal to the transplant renal artery (Prox-TRAS) is an uncommon cause of graft dysfunction and hypertension. We assessed the role of duplex sonography (DS) in regard to clinical and angiographic findings and followed the patients after percutaneous transluminal angioplasty (PTA), PTA stenting (PTAS), or surgery.

METHODS

From January 1988 to August 2001, 97 of 1,064 kidney recipients underwent angiography for clinical or Doppler-sonographic suspicion of vascular problems. Kidney function, blood pressure, medication, and DS findings after renal transplantation (RTx) at the time of diagnosis of Prox-TRAS and after treatment were evaluated.

RESULTS

Prox-TRAS was diagnosed in 16 patients (1.5%) (49.6+/-6.9 years). Four patients demonstrated early presentation of Prox-TRAS 1 to 7 days after RTx (group A), leading to acute renal failure but without hypertension. In all patients, DS revealed pulsus parvus et tardus, low pulsatility index (PI) (<1.0), and a pathologic flow profile in the iliac artery proximal and distal to the graft. After treatment (surgery in two patients, PTA in one patient, PTAS in one patient), all patients developed good renal function (creatinine 1.7+/-0.9 mg/dL). PI increased from 0.9+/-0.1 to 1.2+/-0.1 (P=0.04), and flow profile within the iliac artery distal to the graft normalized. Late presentation (3-209 months after RTx) of Prox-TRAS was observed in 12 patients (group B), causing an increase of creatinine in 11 patients (two patients receiving dialysis treatments), impairment of blood pressure (141+/-15 and 80.7+/-7 to 160+/-18 and 85+/-7 mm Hg, P=0.009), and an increase in antihypertensive drugs (2.1+/-1.1 and 4.3+/-1, P=0.003) in all patients. The PI was decreased when compared with values early after RTx (1.6+/-0.4 to 1.2+/-0.3, P=0.007), and flow profile in the iliac artery was pathologic. All patients except one were managed by surgery (n=6), PTA (n=1), or PTAS (n=4). Creatinine (2.7+/-1.4 to 1.8+/-0.4 mg/dL, P=0.02) and blood pressure (160+/-18/85+/-7 mm Hg to 138+/-7/82+/-9, P=0.018) improved. Antihypertensive drugs were reduced to 2.8+/-0.8 (P=0.01). PI increased from 1.2+/-0.3 to 1.9+/-0.5 (P=0.01). Flow profile within the iliac artery distal to the graft anastomosis normalized. Kidney function, blood pressure, and PI remained unchanged during follow-up (82+/-69.9 months) in both groups.

CONCLUSIONS

Prox-TRAS is rare. Because clinical symptoms are similar to those of transplant renal artery stenosis, DS is a valuable tool for diagnosis and follow-up for this type of vascular lesion. Selective treatment with PTA, PTAS, or surgery improves kidney function and hypertension.

The role of interventional radiology in management of patients with end-stage renal disease

The aim of the paper is to review the role of interventional radiology in the management of hemodialysis vascular access and complications in renal transplantation. The evaluation of patients with hemodialysis vascular access is complex. It includes the radiology/ultrasound (US) evaluation of the peripheral veins of the upper extremities with venous mapping and the evaluation of the central vein prior to the access placement and radiological detection and treatment of the stenosis and thrombosis in misfunctional dialysis fistulas. Preoperative screening enables the identification of a suitable vessel to create a hemodynamically-sound dialysis fistula. Clinical and radiological detection of the hemodynamically significant stenosis or occlusion demands fistulography and endovascular treatment. Endovascular prophylactic dilatation of stenosis greater than 50% with associated clinical abnormalities such as flow-rate reduction is warranted to prolong access patency. The technical success rates are over 90% for dilatation. One-year primary patency rate in forearm fistula is 51%, versus graft 40%. Stents are placed only in selected cases; routinely in central vein after dilatation, in ruptured vein and elastic recoil. Thrombosed fistula and grafts can be declotted by purely mechanical methods or in combination with a lytic drug. The success rate of the technique is 89-90%. Primary patency rate is 8-26% per year and secondary 75% per year. The most frequently radiologically evaluated and treated complications in renal transplantation are perirenal and renal fluid collection and abnormalities of the vasculature and collecting system. US is often the method of choice for the diagnostic evaluation and management of the percutaneous therapeutic procedures in early and late transplantation complications. Computed tomography and magnetic resonance are valuable alternatives when US is inconclusive. Renal and perirenal fluid collection are usually treated successfully with percutaneous drainage. Doppler US, magnetic resonance angiography and digital subtraction angiography have a principle role in the evaluation of vascular complications of renal transplantation and management of the endovascular therapy. Stenosis, the most common vascular complication, occurs in 1-12% of transplanted renal arteries and represents a potentially curable cause of hypertension following transplantation and/or renal dysfunction. Treatment with percutaneous transluminal renal angioplasty (PTRA) or PTRA with stent has been technically successful in 82-92% of the cases, and graft salvage rate has ranged from 80 to 100%. Restenosis occurs in up to 20% of cases, but are usually amenable to repeated PTRA. Complications such as arterial and vein thrombosis are uncommon. Intrarenal A/V fistulas and pseudoaneurysms are occasionally seen after biopsy, the treatment requires superselective embolisation. Urologic complications are relatively uncommon, predominantly they consist of the urinary leaks and urethral obstruction. Interventional treatment consists of percutaneous nephrostomy, balloon dilation, insertion of the double J stents, metallic stent placement and external drainage of the extrarenal collections.

Early posttransplantation renal allograft perfusion failure due to dissection: diagnosis and interventional treatment

OBJECTIVE

The aim of our study was to describe the role of interventional radiology, especially in the use of vascular stents, in early renal perfusion failure after transplantation.

CONCLUSION

Angiography revealed intimal dissection of the graft artery and graft venous thrombosis, which were successfully treated with stent angioplasty and thromboaspiration. For early vascular complication after transplantation, timely use of angiography and subsequent intervention should be recognized as potentially effective and safe treatment techniques.

Treatment of hypertension in renal transplant recipients

PURPOSE OF REVIEW

Hypertension is very common in renal transplant recipients and is a significant risk factor for mortality from cardiovascular diseases and for development of graft dysfunction.

RECENT FINDINGS

Recent guidelines for the treatment of hypertension (Joint National Committee on Prevention, Detection, and Treatment of High Blood Pressure VI Report and World Health Organization Guidelines) do not directly address post-transplant hypertension. Specific recommendations for the drug treatment of hypertension in renal allograft recipients have not been given in the Clinical Practice Guidelines of the American Society of Transplantation or those of the European Renal Association.

SUMMARY

The present paper summarizes some important aspects of post-transplant hypertension and discusses potential treatment strategies aimed at reducing blood pressure and thus improving patient and allograft survival.