Endovascular treatment of renal artery stenosis

Sirolimus-eluting stent placement for refractory renal artery in-stent restenosis: sustained patency and clinical benefit at 24 months

Abstract

Renal artery stenosis may cause or exacerbate hypertension and renal failure. Percutaneous transluminal renal artery stent placement, increasingly the first-line therapy for ostial atherosclerotic renal artery stenosis, can be complicated by in-stent restenosis weeks to months after the procedure. There is currently no consensus for the treatment of in-stent restenosis. Sirolimus-eluting stents have been shown to be effective to treat in-stent restenosis in the coronary circulation. We report a case of sustained 24-month patency after repair of recurrent renal artery in-stent restenosis with use of a sirolimus-eluting stent.

RADAR - A randomised, multi-centre, prospective study comparing best medical treatment versus best medical treatment plus renal artery stenting in patients with haemodynamically relevant atherosclerotic renal artery stenosis

BACKGROUND

Prospective, international, multi-centre, randomised (1:1) trial to evaluate the clinical impact of percutaneous transluminal renal artery stenting (PTRAS) on the impaired renal function measured by the estimated glomerular filtration rate (eGFR) in patients with haemodynamically significant atherosclerotic renal artery stenosis.

METHODS

Patients will be randomised to receive either PTRAS using the Dynamic Renal Stent system plus best medical treatment or best medical treatment. Renal stenting will be performed under angiographic imaging. For patients randomised to best medical treatment the degree of stenosis measured by renal duplex sonography (RDS) will be confirmed by MR angio or multi-slice CT where possible. Best medical treatment will be initiated at randomisation or post procedure (for PTRAS arm only), and adjusted as needed at all visits. Best medical treatment is defined as optimal drug therapy for control of the major risk factors (blood pressure < or = 125/80 mmHg, LDL cholesterol < or = 100 mg/dL, HbA1c < or = 6.5%). Data recordings include serum creatinine values, eGFR, brain natriuretic peptide, patients' medical history and concomitant medication, clinical events, quality of life questionnaire (SF-12v2), 24 hour ambulatory blood pressure measurement, renal artery duplex ultrasound and echocardiography. Follow-up intervals are at 2, 6, 12 and 36 months following randomisation.The primary endpoint is the difference between treatments in change of eGFR over 12 months. Major secondary endpoints are technical success, change of renal function based on the eGFR slope change between pre-treatment and post-treatment (i.e. improvement, stabilisation, failure), clinical events overall such as renal or cardiac death, stroke, myocardial infarction, hospitalisation for congestive heart failure, progressive renal insufficiency (i.e. need for dialysis), need of target vessel revascularisation or target lesion revascularisation, change in average systolic and diastolic blood pressure, change in left ventricular mass index calculated from echocardiography, difference in the size of kidney (pole to pole length) measured by renal duplex sonography, total number, drug name, drug class, daily dose, regimen and Defined Daily Dose (DDD), of anti-hypertensive drugs, and change in New York Heart Association (NYHA) classification. Approximately 30 centres in Europe and South America will enrol patients. Duration of enrolment is expected to be 12 months resulting in study duration of 48 months.

TRIAL REGISTRATION

TRIAL REGISTRATION NUMBER

NCT00640406.

Angioplasty for Non-arteriosclerotic Renal Artery Stenosis: The Efficacy of Cutting Balloon Angioplasty Versus Conventional Angioplasty

PURPOSE

We examined the efficacy of conventional balloon angioplasty and cutting balloon angioplasty (CBA) for the treatment of non-arteriosclerotic renal artery stenosis (RAS).

MATERIALS AND METHODS

From 1993 to 2005, 20 patients underwent 27 percutaneous transluminal renalangioplasty (PTRA) for non-arteriosclerotic RAS (men: 8, women: 12, 25.5 +/- 2 years old; 16 fibromuscular dysplasia (FMD), 4 Takayasu disease). We evaluated the efficacy of CBA by comparing the rate of initial technical success and surgical conversion.

RESULTS

Before the clinical authorization of CBA, three of twelve patients (25 %) underwent surgical bypass due to the failure of PTRA due to the hardness of the lesion. After the approval of cutting balloon, we performed CBA in four cases (2 FMD,2 Takayasu disease) to dilate hard lesions, within which a properly sized balloon could not dilate due to their hardness, or to reduce the risk of local dissection. Initial successes were obtained in all patients (8/8, 100%) and none of the patients underwent surgical conversion. Despite of the good initial result, restenosis was observed in three cases within 6 month (3/4, 75%). Additional interventions were performed in all patients, then, the severity of the restenotic lesion was found not to be exceeded comparing with the initial lesion.

CONCLUSION

The cutting balloon angioplasty may be safe and useful procedure for hard lesions of RAS caused by non-arteriosclerotic disease? especially fibromuscular dysplasia. The cutting balloon may provide the initial success, but the effect on long-term patency is still controversial.

Durability of renal artery stents in patients with transrenal abdominal aortic endografts

OBJECTIVE

The management of renal artery stenosis in patients with abdominal aortic aneurysms continues to be complex and technically challenging despite advances in endovascular therapy. There is growing concern about the durability of renal artery stents in the setting of transrenal abdominal aortic endografts. This study reports a single-center experience of renal artery stenting with transrenal abdominal aortic endografts for patients with renal artery stenosis.

METHODS

All patients undergoing endovascular abdominal aortic aneurysm repair preceded or followed by renal artery stent placement between January 1999 and December 2005 were retrospectively reviewed from a prospectively gathered endovascular database. Patients were surveyed after renal stent procedures with multidetector computed tomography angiography or duplex sonography. The surveillance data were analyzed for primary patency of the renal artery stent at 6 months, incidence of complications, need for secondary interventions, and changes in creatinine clearance (CrCl).

RESULTS

Sixty-two renal artery stents were placed in 56 patients (44 men, 12 women) with a mean age of 77.3 years (range, 61 to 94 years). Forty-one were placed before the endograft procedure, eight were placed during the endograft procedure, and 13 were placed postoperatively. There were no major or minor complications related to the renal artery stent procedures. Transrenal aortic endografts were used in 44 of the 56 patients, and 12 had devices with infrarenal fixation. The mean follow-up was 18.5 months (range, 1 to 73 months). The 6-month primary patency, which could be evaluated for 51 renal artery stents, was 97.4% (37/38) in patients with transrenal fixation and 84.6% (11/13) in patients with infrarenal fixation. The overall rate of in-stent restenosis was 8.5% (4/47) in the transrenal fixation group and 20.0% (3/15) in the infrarenal fixation group. The overall occlusion rate was 2.1% (1/47) in the transrenal fixation group and 0% (0/15) in infrarenal fixation group. Five (83.3%) of six patients underwent successful treatment of in-stent restenosis with placement of a new stent in all five cases. CrCl decreased in the total group by 4.2 +/- 11.8 mL/min, by 4.7 +/- 12.0 mL/min in patients with transrenal fixation, and by 2.2 +/- 11.0 mL/min in patients with infrarenal fixation.

CONCLUSION

The presence of a transrenal aortic endograft did not affect the outcome of the renal artery revascularization procedure in this cohort. Renal artery stenting in the presence of transrenal abdominal aortic endografts appears to be a safe procedure without adverse effect on renal artery stent patency or renal function.

Safety of Angiotensin-Converting Enzyme Inhibitors in Patients with Bilateral Renal Artery Stenosis Following Successful Renal Artery Stent Revascularization

Angiotensin-converting enzyme inhibitors (ACEIs) are contraindicated in patients with bilateral renal artery stenosis due to risk of azotemia resulting from preferential efferent arteriolar vasodilation in the renal glomerulus due to inhibition of angiotensin II. Patients with renal artery stenosis who can derive survival benefit from ACE inhibition, therefore, may not receive ACEI therapy. We evaluated the safety of ACEI therapy in patients with bilateral renal artery stenosis following successful revascularization using renal artery stenting. This study is a retrospective analysis of 25 patients who underwent bilateral renal artery stenting for refractory hypertension and had a strong clinical indication for long-term ACEI use (left ventricular dysfunction or diabetes). Eighteen of the 25 patients (72%) have been safely maintained on a target dose of ACEIs, 2 of the 25 have been treated with angiotensin receptor blockers due to cough, and 5 of the 25 are being treated with a hydralazine/nitrate combination due to cough (2 patients) or baseline renal insufficiency (3 patients). We conclude that patients with bilateral renal artery stenoses that have been successfully revascularized using renal stenting may be safely treated with long-term ACEI therapy.

Percutaneous Transluminal Renal Angioplasty (PTRA) and Surgical Revascularisation in Renovascular Disease—A Retrospective Comparison of Results, Complications, and Mortality

OBJECTIVE

To evaluate results, complications and mortality following percutaneous transluminal renal angioplasty (PTRA) and open surgical revascularisation for renovascular disease.

METHODS

A retrospective evaluation of 381 renovascular patients (median age 64, range 9-99 years, 152 women) treated at Malmö University Hospital during 1987-1996. Two hundred and sixty-two (69%) of the patients were treated with PTRA, 106 (28%) with open revascularisation.

RESULTS

Thirty-day mortality was 2% in the PTRA group and 9% after open surgery (p<0.001). There were no differences between groups concerning the number of re-do procedures, but first re-do was performed after seven (IQR 3-14) months in the PTRA group, and after 15 (IQR 10-44) months after open revascularisation (p<0.0001). After a median follow-up of 4 months (IQR 0-13) systolic and diastolic blood pressure (BP) had decreased (p<0.0001) in both groups. The number of antihypertensive drugs was reduced (p<0.0001) and S-creatinine levels were unchanged in both groups. Long-time survival assessed with log-rank analysis was better (p<0.01) in the PTRA group. The risk ratio for death with open revascularisation was 1.69 (p<0.01).

CONCLUSIONS

In this retrospective comparison, PTRA was as effective as open revascularisation, with lower complication rate and lower early and long-time mortality, but with shorter time to first re-do.

Current issues in the diagnosis and management of patients with renal artery stenosis: a cardiologic perspective

Renal artery stenosis most often is caused by atherosclerosis. Although patients with renal artery stenosis can be managed conservatively, renal revascularization may be indicated, particularly in patients with refractory hypertension on a multidrug regimen and patients with declining renal function. Duplex ultrasonography of the renal arteries and magnetic resonance angiography are currently the most efficient noninvasive methods for the evaluation of renal artery stenosis. Selective digital subtraction renal arteriography remains the gold standard for the definitive diagnosis. In selected patients undergoing coronary studies and angiography immediately after the coronary procedure can be efficient. Atherosclerotic renal artery lesions, which commonly affect the renal artery ostium, can be treated safely and effectively with balloon-expandable stents. Successful angioplasty commonly results in improved control of hypertension, but an overall benefit on renal function and/or patient survival has not been shown. Generally the risk/benefit ratio of renal artery stenting seems favorable, but further randomized studies are needed for evidence-based decision making. All patients with atherosclerotic renal artery stenosis should receive rigorous secondary prevention measures including platelet inhibitors, statins, and beta-blockers.

Delayed pseudoaneurysm after renal artery angioplasty

PURPOSE

To report delayed pseudoaneurysm formation after percutaneous renal artery angioplasty.

CASE REPORTS

A 56-year-old woman succumbed to complications of a ruptured right juxtarenal aortic pseudoaneurysm 2 years after right renal artery stenting for renal impairment. The juxtarenal aorta had been normal on aortography at the time of angioplasty. She gave a history of right-sided back pain that started within 8 months of the angioplasty. A 21-year-old woman with left renal artery stenosis due to fibromuscular dysplasia was treated with balloon angioplasty, after which there was evidence of active extravasation. The completion angiogram, after a period of observation, documented cessation of the leak. Follow-up angiography because of persisting hypertension disclosed a large, asymptomatic, intrarenal pseudoaneurysm that was repaired with bench surgery and autotransplantation.

CONCLUSIONS

We advise that patients with symptoms referable to the site of renal artery intervention and those who have had complicated interventions should have follow-up imaging to exclude pseudoaneurysm formation.