Primary stenting for atherosclerotic renal artery stenosis

[In-hospital results of renal artery stenting in patients with multifocal atherosclerosis]

OBJECTIVE

A retrospective analysis of in-hospital results of renal artery stenting in patients with multifocal atherosclerosis.

MATERIAL AND METHODS

The study included 19 patients who underwent stenting for renal artery stenosis for the period 2011-2015 in the Kemerovo Cardiology Dispensary. Renal function was assessed considering glomerular filtration rate (GFR). Blood pressure and GFR were evaluated before the stenting procedure and at discharge.

RESULTS

Stenting resulted optimal outcomes in all 19 patients. Severity of residual stenosis was 11±3%. In-hospital mortality was absent. Blood pressure in early postoperative period was similar to baseline values. One patient had a normalization of blood pressure up to 115-140/85-90 mm Hg without administration of antihypertensive drugs. Decrease of systolic blood pressure up to 155.3±32.6 mm Hg was noted in other patients at discharge. Blood creatinine levels decreased up to 0.167±0.56 mmol/L. In addition, mean GFR increased from 34.17 ml/min/1.69 m² up to 37.16 ml/min/1.69 m².

CONCLUSION

Endovascular treatment of renal artery stenosis and secondary hypertension is effective and relatively safe approach.

Is stenting for atherosclerotic renal stenosis an effective technique?

INTRODUCTION

One of the treatments for renal artery stenosis is endovascular intervention, but its effectiveness is controversial. The present study aims to analyze the experience of a working group in the endovascular treatment of selected patients with severe obstructive atherosclerotic lesions of the renal arteries, and to characterize early and late results.

METHODS

This is a retrospective study of symptomatic patients with atherosclerotic renal artery stenosis who underwent endoluminal therapy between May 12, 1999 and March 12, 2015 at two institutions. Statistical analysis was performed using the PASW Statistics program.

RESULTS

A total of 99 patients were treated, mean age 66 years and 76.8% male. The mean degree of stenosis measured by renal Doppler echocardiography was 83% and 64.6% were ostial lesions. Mean preoperative creatinine level was higher than the postoperative mean: 1.3 vs. 1.2 mg/dl (p=0.014). The number of antihypertensive drugs in the preoperative period was higher than in the postoperative period: 2.0 vs. 1.3 (p=0.001). The mean follow-up was 40 months (0-164). The mean peak systolic velocity over time in the postoperative period was 77 cm/s (40-250). The restenosis rate was 8%, and 30-day mortality was 0%.

CONCLUSIONS

The results demonstrated that the endovascular technique has a beneficial effect on blood pressure and renal function in selected patients, and is a safe technique associated with a high rate of technical success and few complications.

Atherosclerotic Renal Artery Stenosis and Hypertension: Pragmatism, Pitfalls, and Perspectives

For many years and even decades, a diagnostic work-up to look for a secondary form of hypertension, particularly of renovascular origin, has been a central tenet in medicine. Atherosclerotic renal artery stenosis is considered the most common cause of renovascular hypertension. However, advances in understanding the complex pathophysiology of this condition and the recently documented futility of renal revascularization bring into question whether atherosclerotic renal artery stenosis truly causes "renovascular hypertension." From a clinical point of view, a clear distinction should be made between hypertension associated with atherosclerotic renal artery stenosis and hypertension caused by renal artery stenosis-induced activation of the renin-angiotensin-aldosterone system. Most patients with atherosclerotic renal artery stenosis do not have a form of hypertension that is remediable or improved by angioplasty; to expose them to the cost, inconvenience, and risk of a diagnostic work-up add up to little more than a wild goose chase. However, with very few exceptions, medical therapy with antihypertensives and statins remains the cornerstone for the management of patients with atherosclerotic renal artery stenosis and hypertension.

Clinical effectiveness of secondary interventions for restenosis after renal artery stenting

OBJECTIVE

Secondary interventions for renal artery restenosis (RAS) after renal artery stenting are common, despite limited data about their effectiveness. This study was designed to evaluate the outcomes of endovascular treatment of recurrent RAS.

METHODS

We conducted a retrospective review of patients who underwent renal artery stenting between 2001 and 2011 at Dartmouth-Hitchcock Medical Center. Patients who required secondary interventions were compared with control patients who underwent only primary interventions for RAS. Multivariate regression models were used to identify factors associated with successful outcomes, as measured by changes in blood pressure, estimated glomerular filtration rate, and number of antihypertensive medications required.

RESULTS

Sixty-five secondary (57 patients) renal interventions were undertaken for recurrent RAS associated with progressive hypertension or renal dysfunction and compared with outcomes after 216 primary (180 patients) renal artery stenting procedures. Patients undergoing primary vs secondary interventions did not differ significantly in the number of preoperative antihypertensive medications used, comorbid conditions, or blood pressure. All primary and secondary interventions were performed with stents and showed no difference in procedural complications. At a mean follow-up of 23 months (range, 1-128 months), similar improvements in renal function and blood pressure were found between patients undergoing primary and secondary interventions, and there was no difference in rates of restenosis or survival between cohorts. Regression models showed that the use of embolic protection devices was associated with improved renal function after primary (odds ratio [OR], 2.0; 95% confidence interval [CI], 1.1-3.8; P < .05) and secondary (OR, 4.7; 95% CI, 1.7-12.5; P < .05) interventions, whereas statin therapy was associated with improved renal (OR, 2.0; 95% CI, 1.3-3.2; P < .05) and blood pressure response (OR, 4.1; 95% CI, 1.1-14.9; P < .05) after secondary interventions.

CONCLUSIONS

Patients undergoing secondary interventions for recurrent RAS have outcomes that are comparable with those for primary interventions. These data suggest that repeated endovascular procedures for RAS can be undertaken with similar expectations for clinical improvement and may be further improved by routine use of embolic protection devices and statin therapy.

Percutaneous revascularization for ischemic nephropathy: the past, present, and future

Occlusion of the renal arteries can threaten the viability of the kidney when severe, in addition to accelerating hypertension and circulatory congestion. Renal artery stenting procedures have evolved from a treatment mainly for renovascular hypertension to a maneuver capable of recovering threatened renal function in patients with “ischemic nephropathy” and improving management of congestive heart failure. Improved catheter design and techniques have reduced, but not eliminated hazards associated with renovascular stenting. Expanded use of endovascular stent grafts to treat abdominal aortic aneurysms has introduced a new indication for renal artery stenting to protect the renal circulation when grafts cross the origins of the renal arteries. Although controversial, prospective randomized trials to evaluate the added benefit of revascularization to current medical therapy for atherosclerotic renal artery stenosis until now have failed to identify major benefits regarding either renal function or blood pressure control. These studies have been limited by selection bias and have been harshly criticized. While studies of tissue oxygenation using blood oxygen level dependent (BOLD) MR establish that kidneys can adapt to reduced blood flow to some degree, more severe occlusive disease leads to cortical hypoxia associated with microvascular rarefication, inflammatory injury and fibrosis. Current research is directed toward identifying pathways of irreversible kidney injury due to vascular occlusion and to increase the potential for renal repair after restoring renal artery patency. The role of nephrologists likely will focus upon recognizing the limits of renal adaptation to vascular disease and identifying kidneys truly at risk for ischemic injury at a time point when renal revascularization can still be of benefit to recovering kidney function.

Changing trends in a decade of vascular radiology-the impact of technical developments of non-invasive techniques on vascular imaging

OBJECTIVES

This review aims to establish the impact on conventional angiography and endovascular intervention of contrast-enhanced magnetic resonance angiography (CE-MRA) and contrast-enhanced computed tomography angiography (CE-CTA) on a background of evolving technology, changing clinical requirements and resulting clinical repercussions.

METHODS

The angiographic and interventional caseload was prospectively recorded between 1997 and 2010, along with the CE-MRA and CE-CTA caseload. Waiting times and the marginal cost analyses for 2001 and 2009 were also prospectively established.

RESULTS

Conventional diagnostic angiographies declined from a peak of 847 to 121 per year while endovascular interventions continue in similar numbers. CE-MRA increased from effectively none initially to 620 per year while CE-CTA has currently risen to 396 per year. Total diagnostic study numbers have increased but at reduced cost. Various influences are clear, including on-site modality availability, capability and accuracy along with impact of new therapies, research studies and adverse events.

CONCLUSIONS

Vascular imaging has undergone a metamorphosis in little over a decade because of CE-MRA and CE-CTA. With waiting times significantly reduced since the start of the study and the cost-effectiveness of both CE-MRA and CE-CTA as primary diagnostic investigations established, further development of these services is inevitable.

MAIN MESSAGES

• The availability of CE-MRA and CE-CTA has reduced the need for conventional angiography. • Both waiting times and the marginal cost analyses for CE-MRA and CE-CTA have reduced. • The impact of new therapies, research studies (e.g. ASTRAL) and adverse events is illustrated.

[Contribution of angioplasty of a fibromuscular angiodysplasic renal artery during early-onset gestational hypertension]

This clinical case illustrates the management difficulties encountered during gestational hypertension and its impact on maternal and foetal outcome. Typically, preeclampsia occurs at the end of the second trimester. If blood pressure remains high early during pregnancy, a secondary cause of hypertension such as renal artery fibromuscular dysplasia should be explored. A renal vascular etiology can be safely ruled out with a duplex ultrasound. In this particular case of renal vascular hypertension in a patient with a single kidney, angioplasty appeared to be the sole solution and was efficient.

Preoperative preparation of vascular patients undergoing nonvascular surgery

Patients with vascular diseases mainly caused by atherosclerosis, that are undergoing nonvascular surgery, often have co-existing conditions which affect their cardiovascular system. Cardiovascular complications are among the most common perioperative complications including respiratory complications and infections. These include coronary disease, hypertension, heart insufficiency, pulmonary hypertension, and renovascular hypertension, among others. Preoperative preparation must include the use of beta-blocker therapy, antihypertensive, antithrombotic and antilipogenic therapy. Electrocardiogram (ECG) and trans-thoracic echocardiography are the minimum preoperative diagnostic evaluations that should be performed, because complications may arise even in patients without prior cardiovascular symptomatology. Venous diseases are the most common contemporary diseases affecting people of all age groups and races. Invasive-diagnostic-therapeutic procedures may cause lesions of venous endothelium, hence perioperative prevention of deep vein thrombosis (DVT) with the use of heparin or low-molecular -weight heparin (LMWH) should be undertaken.