Endovascular Therapy of Renal Artery Stenosis: Where Do We Stand Today?

Percutaneous renal artery stent implantation in the treatment of atherosclerotic renal artery stenosis

We aimed to investigate the clinical curative effect of percutaneous renal artery stent implantation (PTRAS) in the treatment of atherosclerotic renal artery stenosis (ARAS), and to analyze the factors influencing the curative effect of PTRAS. A total of 230 patients with unilateral or bilateral renal artery stenosis were retrospectively analyzed. According to whether adverse cardiogenic or nephrogenic events occurred, 230 patients were divided into two groups to analyze the risk factors of adverse cardiogenic or nephrogenic events. The blood pressure of patients at each time-point after operation was decreased significantly compared with that before operation (P<0.01). The levels of serum creatinine (SCr) at 24 h and 36 months after PTRAS were slightly increased compared with that before operation (P>0.05). The estimated glomerular filtration rate (eGFR) at each time-point after operation was slightly decreased compared with that before operation, but the difference was not statistically significant (P>0.05). Renography showed that GFR on the side of stent implantation at 36 months after PTRAS had no significant change compared with that before operation (P>0.05), but GFR on the unaffected side without receiving PTRAS was significantly increased compared with that before operation (P=0.0014). During the 36-month follow-up, there were a total of 56 cases of adverse cardiogenic or nephrogenic events. Multivariate regression analysis results showed that adverse cardiogenic or nephrogenic events after PTRAS were obviously associated with age (≥65 years old), Charlson comorbidity index (CCI) score (≥2 points), diabetes mellitus, stroke and congestive heart failure (CHF) (P<0.05). In conclusion, PTRAS can effectively control the blood pressure and reduce the types of antihypertensive drugs used by patients with ARAS, but it has no definitely protective effect on renal function. Age (≥65 years old), CCI score (≥2 points), diabetes mellitus, stroke and CHF are risk factors leading to adverse cardiogenic or nephrogenic events after PTRAS.

Non-coronary atherosclerosis

During the last decades, the clinical and research interest in atherosclerosis has been mostly focused on coronary arteries. After the publications of the European Society Guidelines and AHA/ACC Guidelines on Peripheral artery diseases, and of the Registry REduction in Atherothrombosis for Continued Health Registry, there has been an increased interest in atherosclerosis of the lower extremity arteries and its presence in multifocal disease. However, awareness in the general population and the medical community of non-coronary artery diseases, and of its major prognostic implications remain relatively low. The aim of this general review stemming out of an ESC Working Group on Peripheral Circulation meeting in 2011 is to enhance awareness of this complex disease highlighting the importance of the involvement of atherosclerosis at different levels with respect to clinical presentation, diagnosis, and co-existence of the disease in the distinct arterial territories. We also emphasize the need of an interdisciplinary approach to face the broad and complex spectrum of multifocal disease, and try to propose a series of tentative recommendations and measures to be implemented in non-coronary atherosclerosis.

[State of the art: interventional radiology management of renovascular hypertension]

The management of renal artery stenosis (RAS) has been the subject of numerous clinical studies and recommendations, most frequently with regards to atherosclerotic RAS. We present the current recommendations from the French Society of Cardiac and Vascular Imaging updated from a recent literature review (April 2008) with regards to medical, endovascular and surgical management of atheroscletotic and non-atherosclerotic RAS. The evidence-based recommendations are ranked by level.

High-resolution 3D contrast-enhanced MRA with parallel imaging techniques before endovascular interventional treatment of arterial stenosis

This study aimed to evaluate the efficacy of high-resolution 3D contrast-enhanced magnetic resonance angiography (3D CE MRA) with parallel imaging techniques for the diagnosis of various arterial stenoses and its value for planning endovascular interventional treatment. Thirty-five patients underwent 3D CE MRA before endovascular interventional treatment. Numbers of patients were as follows: clinically documented renal artery stenosis (n = 10), renal transplant artery stenosis (n = 1), carotid artery stenosis (n = 12), iliac artery stenosis (n = 11) and femoro-popliteal artery stenosis (n = 1). A total of 39 arterial segments were treated. The depiction of various arterial stenoses was evaluated. The degree and length of the stenoses were compared and analyzed between 3D CE MRA and digital subtraction angiography (DSA). The accuracy of MRA in depicting lesion characteristics (ulceration, eccentricity, post-stenotic dilatation) was reviewed. The overall value of 3D CE MRA in planning interventional treatment was determined. The quality of 3D CE MRA in the demonstration of various arterial stenoses was judged excellent or good. A strong correlation was noted between 3D CE MRA and DSA regarding severity and length of stenosis. The accuracy of 3D CE MRA in depicting lesion characteristics was good. 3D CE MRA overestimated three severe iliac artery stenoses. Except in these three segments, the value of 3D CE MRA analysis was judged high. 3D CE MRA was found to be better than DSA in revealing the distal reconstitution and occluded segment in cases of iliac artery stenosis. 3D CE MRA is accurate in demonstrating the relevant anatomy necessary to plan endovascular interventional treatment for patients with arterial stenosis.

Recovery of renal function after delayed percutaneous dilation of a subtotal in-stent restenosis of the renal artery in a left solitary kidney

In-stent restenosis of a previously atherosclerotic renal artery stenosis initially treated with endovascular stenting may progress to subtotal occlusion and loss of renal function. The clinical course of an acute occlusion is mainly acute oligo-anuric renal failure. Therefore, rapid diagnosis and treatment are critical for renal survival. Even after successful endovascular treatment, a close clinical monitoring, and optimized medical treatment including sufficient blood pressure control, lipid lowering and platelet inhibition, is mandatory to prolong the preservation of renal function. Here we present a patient with subtotal in-stent stenosis affecting the left solitary kidney and recovery of renal function 24 h after the revascularization procedure.

Estimation of the Ratio of Renal Artery Stenosis with Magnetic Resonance Angiography Using Parallel Imaging Technique in Suspected Renovascular Hypertension

BACKGROUND

Renovascular hypertension, which may lead to end-stage renal failure, necessitates prompt diagnosis and medication. Although various diagnostic tools exist for evaluation of renal arteries, magnetic resonance angiography (MRA), with the improvement of hardware and software systems, has become a very promising technique in screening patients with suspected renal hypertension. In this study, we aimed to assess renal artery stenosis on MRA in patients with suspected renovascular disease using a parallel imaging technique which allows faster scanning with higher resolution.

METHODS

Eighty-four patients with hypertension underwent MRA and digital angiography.

RESULTS

MRA detected renal artery stenosis with a sensitivity rate ranging from 69.3 to 100% and specificity rate ranging from 85.7 to 96%.

CONCLUSION

Contrast-enhanced MRA of renal arteries is very effective in the demonstration of renal artery stenoses and assessment of stenosis ratio. Furthermore, parallel imaging technology has improved this procedure by reducing the scan time. Renal MRA, as a diagnostic tool, can accurately direct patients with renovascular disease to intravascular treatment.

Renal MR and CT angiography: current concepts

During the past decade, noninvasive CTA and MRA imaging techniques have replaced catheter angiography for evaluation of the renal arteries. This article reviews techniques for optimizing renal MRA and CTA, assesses the advantages and limitations of MRA and CTA, and provides the current indications for renal vascular imaging including renal artery stenosis screening. New and future developments in these rapidly evolving techniques are also discussed.

Clinical experience and applications of drug-eluting stents in the noncoronary vasculature, bile duct and esophagus

OBJECTIVE

To review the use of drug-eluting stents outside the coronary artery.

FINDINGS

The vast majority of research and clinical data on drug-eluting stents are from their use in coronary artery atherosclerosis; however, these devices can be used outside the coronary circulation in both vascular and nonvascular structures. In noncoronary arteries the principle indication for drug-eluting vascular stents is the same as in the coronary circulation, prevention of restenosis. Human experience has been essentially limited to trials or compassionate use; two small controlled studies and a number of small observational single center reports have been published, and there are trials in progress. To date the data have not been as compelling as in the coronary circulation. The physical characteristics of each vascular bed such as external compressive forces, blood flow rates, wall thickness relative to lumen size, and vessel wall composition differ significantly from the coronary circulation and each presents unique challenges to local drug delivery. Outside the vascular bed, the principle expected use is the prevention of tissue ingrowth after stent insertion in tubular structures such as the trachea, esophagus or bile ducts.

CONCLUSIONS

Considerable further study of drug-eluting stents will be required in each anatomic region to determine the ideal stent/drug combination and clinical appropriateness.