Interventional radiologic procedures in the renal transplant

The current state of endovascular therapy in the evaluation and management of renovascular disease

Hypertension is the most common reason for physician office visits among nonpregnant adults in the United States; up to one-third of Americans over the age of 18 have been diagnosed with hypertension. Patients with physiologically significant renal artery stenosis often go unnoticed because hypertension can often be well controlled with antihypertensive medications. As a result, screening for renovascular causes of hypertension is rarely done. However, the likelihood of renovascular disease increases in patients with acute, severe, or refractory hypertension and should be explored in patients who fall into these categories. Renovascular disease is a crucial consideration in the management of hypertension due to its increasing incidence and its potential for reversibility. Although renovascular disease accounts for less than 1% of patients with mild hypertension, it is estimated that between 10 and 45% of white patients with severe or malignant hypertension have renal artery stenosis (RAS). In this population, diagnosing and treating RAS can have a profound and long-lasting effect on the treatment of hypertension.

Rotational digital subtraction angiography of the renal arteries: technique and evaluation in the study of native and transplant renal arteries

Rotational digital subtraction angiography (RDSA) allows multidirectional angiographic acquisitions with a single injection of contrast medium. The role of RDSA was evaluated in 60 patients referred over a 7-month period for diagnostic renal angiography and 12 patients referred for renal transplant studies. All angiograms were assessed for their diagnostic value, the presence of anomalies and the quantity of contrast medium used. The effective dose for native renal RDSA was determined. 41 (68.3%) native renal RDSA images and 8 (66.7%) transplant renal RDSA images were of diagnostic quality. Multiple renal arteries were identified in 9/41 (22%) native renal RDSA diagnostic images. The mean volume of contrast medium in the RDSA runs was 51.2 ml and 50 ml for native and transplant renal studies, respectively. The mean effective dose for 120 degrees native renal RDSA was 2.36 mSv, equivalent to 1 year's mean background radiation. Those RDSA images that were non-diagnostic allowed accurate prediction of the optimal angle for further static angiographic series, which is of great value in transplant renal vessels.

Hepatic artery angioplasty after liver transplantation: experience in 21 allografts

PURPOSE

To assess whether percutaneous transluminal angioplasty (PTA) can help prolong allograft survival and improve allograft function in patients with hepatic artery stenosis after liver transplantation.

PATIENTS AND METHODS

Hepatic artery PTA was attempted in 19 patients with 21 allografts over 12 years. The postangioplasty clinical course was retrospectively analyzed. Liver enzyme levels were measured before and after PTA to determine if changes in liver function occurred after successful PTA.

RESULTS

Technical success was achieved in 17 allografts (81%). Retransplantation was required for four of 17 allografts (24%) in which PTA was successful and four of four allografts in which PTA was unsuccessful; this difference was significant (P = .03). Two major procedure-related complications occurred: an arterial leak that required surgical repair and an extensive dissection that necessitated retransplantation 14 months after PTA. Hepatic failure necessitated repeat transplantation in seven cases from 2 weeks to 27 months (mean, 8.4 months) after PTA. Six patients died during follow-up, three of whom had undergone repeat transplantation. Markedly elevated liver enzyme levels at presentation were associated with an increased risk of retransplantation or death regardless of the outcome of PTA.

CONCLUSION

PTA of hepatic artery stenosis after liver transplantation is relatively safe and may help decrease allograft loss due to thrombosis. Marked allograft dysfunction at presentation is a poor prognostic sign; thus, timely intervention is important.

Urological complications following renal transplantation. A study of 1016 consecutive transplants from a single centre

A total of 1016 consecutive renal transplants performed between 1976 and 1990 were analysed retrospectively to determine the incidence of urological complications and possible predisposing factors. Some 189 episodes of ureteric obstruction and/or urinary leak occurred in 143 patients (overall incidence 14.1%). The median annual rate of urinary leak was 5.1%; that of ureteric obstruction was 4.5% pre-1986 and 16.1% post-1986. Sixty-three episodes of urinary leak occurred in 54 patients from 1 day to 3 months post-transplant and 60% involved the distal ureter. Thirty were treated primarily by reconstructive surgery, ten required nephrectomy and three died of associated sepsis. A total of 126 episodes of ureteric obstruction occurred in 104 patients from 1 day to 12 years post-transplant and 86% involved the distal ureter. Prior to 1986, 10/11 patients with ureteric obstruction were treated by reconstructive surgery, but since then 88 (95%) have been treated by percutaneous nephrostomy, with or without stenting, with only one graft lost and no deaths. Children had a significantly increased incidence of ureteric obstruction (P < 0.001) whilst male recipients had an increased incidence of urinary leak (P = 0.04). More patients with ureteric obstruction than those without had two or more episodes of rejection (P = 0.03). No single cause for the increased incidence of ureteric obstruction since 1986 has been identified. Continued attention to technical detail and further study of this trend is warranted.

Renal transplant artery stenosis in children: treatment with percutaneous transluminal angioplasty

Hypertension due to transplant renal artery stenosis was treated with percutaneous transluminal angioplasty (PTA) in 6 children. 8 angioplasties were performed and the follow-up period varied between 3 and 66 months (average 23 months). The stenoses were located at the site of anastomosis in 4 children and distal to the anastomosis in 2. PTA resulted in improvement of hypertension in all patients, although the need for antihypertensive medication remained. No grafts were lost. Our findings show that PTA of transplant renal artery stenosis in children is a good first choice of treatment.

Transplant renal artery stenosis: experience and comparative results between surgery and angioplasty

One hundred thirty-eight patients with transplant renal artery stenosis (TRAS) were identified among 1200 patients undergoing renal transplantation in our university hospital. Severe systemic hypertension was the main symptom leading to a diagnosis of TRAS. Only 88 TRAS patients were given interventional treatment consisting of percutaneous angioplasty (PTA; n = 49) or surgical repair (SR; n = 39). The immediate success rate was 92.1% for SR and 69% for PTA. The long-term success rate was 81.5% for SR and 40.8% for PTA, with a follow-up period of 56.7 +/- 22.4 months (SR group) and 32 +/- 28.1 months (PTA group). PTA morbidity reached 28%, compared to 7.6% in the SR group. In spite of these results, we still favor PTA as a first line interventional treatment when TRAS is recent, linear, and distal and primary SR in cases of kinking and proximal TRAS.

Percutaneous stone and stent removal from renal transplants

Techniques developed for removal of stones from normally sited kidneys can be safely employed in the transplanted kidney. We describe our experience in removing stones, stent material and organised blood clot from renal transplant collecting systems, using modified percutaneous techniques.

Interventional radiology for restoration of vascular patency in the postoperative patient--case reports

The postoperative patient may present with one or more of a variety of problems amenable to management by interventional radiologic techniques, which may be curative by themselves or may, in addition, require or allow successful surgical intervention. To optimize patient care, a good working relationship between the vascular surgeon and the interventional radiologist is essential. Consideration should be given to the patient's presenting signs and symptoms, the surgical history with its alteration of anatomy, the results of available noninvasive studies, and knowledge of various therapeutic alternatives. Vascular radiologic interventions include angioplasty, thrombolytic therapy, a combination of both angioplasty and thrombolysis, and newer techniques such as percutaneous valvectomy. In this report, examples of some of the experience at Indiana University are presented. Emphasis is placed on the appropriate approach to the patient.

Percutaneous transluminal angioplasty of renal transplant artery stenosis

Renal transplant artery stenosis occurs in approximately 10% of renal transplants, and antihypertensive drugs, vascular reconstructive surgery, and percutaneous transluminal angioplasty may be used in its treatment. Details of 28 cases of renal transplant artery stenosis were collected from a postal survey of United Kingdom transplant centres. The success rate for angioplasty (63% clinical cure or improvement) is lower than in previous reports.

Renal transplant artery stenosis and percutaneous transluminal angioplasty

Ten patients with renal transplant artery stenosis were treated with percutaneous transluminal angioplasty (PTA). All patients suffered from hypertension refractory to drug treatment. PTA was successful in five patients. Blood pressure improved significantly and the antihypertensive medication could be reduced or withdrawn. Acute angulation at the anastomosis prevented successful PTA in four patients. One inaccessible stenosis was corrected surgically. No significant complications arose. If a renal transplant artery stenosis is haemodynamically significant, PTA should be considered the method of first choice for correction.

The transplanted kidney. Diagnostic and interventional radiology

Following kidney allotransplantation a great number of complications threaten the patient and his graft, e.g. acute tubular necrosis, acute and chronic rejection, urologic and vascular complications and complications due to the immunosuppressive treatment. During the last decade a number of technical developments in radionuclide, ultrasonographic and radiographic imaging and intervention has significantly improved the possibility of early recognition and handling of such complications. Knowledge of the capability and limitations of the various techniques is of vital importance for their rational use. The aim of this review article is to give a short description of the various imaging modalities, the rational monitoring of the posttransplant patient, and possible handling of complications by the aid of imaging techniques.