Renal Artery Stent Infection and Pseudoaneurysm Management

Prevalence and Relevance of Multiple Renal Arteries: A Radioanatomical Perspective

Background: A single renal artery supplies the kidney in 70% of the population but variation exists in the remaining 30%. Multiple renal arteries (MRA) in different permutations and combinations are one of the many forms of variants. Lack of awareness of multiplicity could have detrimental effects on the outcome of renal surgery. The present study aims at identifying the variants of renal artery based on its origin, multiplicity, and portal of entry in a cohort of people belonging to Southern India and its clinical implications thereof.

Methods: Multi-detector CT (MDCT) images of renal vasculature of 100 kidneys from 50 live kidney donors who attended the Department of Nephrology of our institution, from 2016 to 2018 were collected and studied for variations in renal arterial anatomy.

Results: Out of the 18% of kidneys observed with multiple renal arteries, 88.8% had double renal arteries (DRA) and 11.1% had triple renal arteries (TRA). Common types of the double renal arteries were - two hilar arteries (31.3%) and one hilar with one inferior polar artery (IPA, 31.3%). Triple renal arteries types - 50% with one hilar, one superior polar, and one inferior polar; 50% with two hilar and one inferior polar artery. No statistically significant association was noted between the incidence of multiple renal arteries and its laterality (p-value=0.193).

Conclusion: A thorough understanding of the renal artery variants is crucial for safe and efficacious uro-radiological interventional procedures.

Endovascular interventions in management of renal artery aneurysm

Renal artery aneurysm (RAA) is a rare disease. With modern non-invasive imaging modalities, the disease is being increasingly diagnosed. It is a slow-growing aneurysm with high mortality in the event of rupture; especially in pregnant females for in which case patients were treated surgically. With advances in endovascular therapy, numerous techniques have been employed to manage complex RAA in artery bifurcation, branch and segmental arteries with excellent technical and clinical success. The various recent techniques include the use of flow diverter stents, remodelling with stent-assisted coil embolization (SACE), balloon-assisted coil embolization (BACE), selective embolization with coils-sac packing, inflow occlusion and coil trapping and selective embolization with liquid embolic agents-hystroacril and onyx. A combination of stent-graft with liquid embolization and liquid with microcoil embolization has been advocated with success. The most common complication encountered is renal infarction. This is mostly without impairment of renal function and secondary to embolization. Endovascular therapy has shorter operative time, less blood loss, shorter intensive care stay, done under conscious sedation and is associated with lesser postoperative morbidity compared to surgery. Reduction in hypertension, improvement of renal function and symptoms has been seen in most studies. Endovascular management of RAA has become the management of choice even with complex anatomy and technically challenging lesions.

Anatomical variations of the renal arterial vasculature: An Australian perspective

INTRODUCTION

Variations of the renal arteries have been studied and published across various population groups, but similar information for the ethnically diverse nation of Australia is lacking. This study describes the pattern of renal artery anomalies in a section of the Australian population based on computed tomography (CT) angiograms of the abdomen and cadaveric dissection.

METHODS

The renal arterial vasculature of 594 kidneys from 300 subjects (28 cadavers, 272 CT) was studied. The number and pattern of renal arteries were categorised on the basis of laterality, point of origin and termination in the kidney (superior pole, hilum and inferior pole), symmetry and sex.

RESULTS

Multiple renal arteries were discovered in 22% of subjects and 12.12% of kidneys. The most common pattern observed was the presence of one variant renal artery (93.1%), compared to the finding of two (5.6%) and three (1.4%) multiple arteries. The aorta was the most frequent site of origin for anomalous vessels, while the hilum was the predominant point of entry. No significant difference was established between left- and right-sided kidneys (13.8% vs. 12.5%; P = 0.627); however, unilateral distribution was more common than bilateral additional renal arteries (16.7% vs. 3.4%; P < 0.01), and variations among males were more than females (27.2% vs. 15.2%; P < 0.05). A higher rate of multiple renal arteries was noted in cadaveric dissections compared to CT images (46.4% vs. 19.5%; P < 0.01).

CONCLUSION

These findings provide application of an evidence-based teaching tool that facilitates education regarding renal arterial variations in Australia.

Infections of intravascular bare metal stents: a case report and review of literature

OBJECTIVE

The objective of the paper is to present a case of an infected bare metal stent in the left common iliac artery that was removed by an urgent operation, and to review the literature on diagnosis and outcome of infected coronary and non-coronary metal stents.

METHODS

A systematic search of the Medline database was performed with the purpose of identifying risk factors, signs and symptoms, imaging strategies, and treatment modalities of bare metal stent infections, both coronary and peripheral.

RESULTS

In total, 76 additional studies/case reports (48 non-coronary; 29 coronary) were included and analyzed. Intravascular bare metal stent infections are a rare but serious complication, often leading to emergency surgery (overall: 75.3%; non-coronary cases: 83.3%; coronary cases: 62.1%). In 25.0% of the non-coronary cases, infection led to amputation of an extremity or removal of viscera. Reported mortality was up to 32.5% of the cases (non-coronary: 22.9%; coronary 48.3%). Physicians should always be suspicious of a stent infection when patients present with aspecific symptoms such as fever and chills after stent placement. Additional imaging can be used to detect the presence of a pseudoaneurysm. A PET-CT is an ideal medium for identification of a stent infection.

CONCLUSIONS

Intravascular stent infection is associated with a high risk of morbidity and mortality. Surgery is the preferred treatment option, but not always possible, especially in patients with a coronary stent. In selected cases, bare metal stent infections may be prevented by the use of prophylactic antibiotics at stent placement.

Renovascular hypertension associated with pseudoaneurysm following blunt trauma

We present the case of a 21-year-old man who developed a renal artery pseudoaneurysm following a 7-foot fall onto his back. He initially presented with gross hematuria, left flank pain, and back pain. He was observed in the hospital for 3 days and discharged. One week later, he was readmitted with headache, nausea, vomiting, seizure activity, and hypertension. Contrast-enhanced computed tomography of the abdomen showed a left renal artery pseudoaneurysm with associated arterial narrowing and delayed ipsilateral renal enhancement. He underwent percutaneous stent-graft placement with resolution of the pseudoaneurysm. He was free of complications and normotensive off antihypertensive medications after 36 months of follow-up. Renal artery pseudoaneurysms are rare and under-recognized complications of blunt abdominal or back trauma that can cause hypertension. Imaging modalities in renovascular hypertension have focused on detecting renal artery stenosis from atherosclerotic disease or fibromuscular dysplasia, with little attention given to renal artery pseudoaneurysms. In addition, first-line treatment for renal artery pseudoaneurysms historically has consisted of angioembolization, yet percutaneous stent-graft placement has emerged as an attractive alternative to preserve vessel patency. We discuss the role of imaging in renovascular hypertension with a focus on renal artery pseudoaneurysms and their prevalence, diagnosis, and treatment.