Endovascular management of atherosclerotic renovascular disease: early results following primary intervention

Endovascular treatments of atherosclerotic renovascular disease: a narrative review and literature search

In recent years, endovascular treatments have become more common in patients with renal artery stenosis and aneurysm. Although the treatment algorithms are not universally accepted, endovascular therapy can be readily utilized for the appropriate indications in the context of surgical treatment for renovascular diseases. The most important factor to consider is that the correct indication is applied for such treatment. Although the applied procedures are believed to have minimal risk, any complications that occur may result in major problems. Moreover, the pathology that is being treated (e.g., hypertension, high serum creatinine concentration, or low glomerular filtration rate) must be well defined. As stent and balloon technologies continue to be developed, more positive results are expected in the coming years. In the present study, we reviewed the endovascular treatment algorithms for atherosclerotic renovascular disease and performed a narrative review of the current literature.

[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.

Update on intervention versus medical therapy for atherosclerotic renal artery stenosis

Atherosclerotic renal artery stenosis is known to be one of the most common causes of secondary hypertension, and early nonrandomized studies suggested that renal artery stenting (RASt) improved outcomes. The vascular community embraced this less invasive treatment alternative to surgery, and RASt increased in popularity during the late 1990s. However, recent randomized studies have failed to show a benefit regarding blood pressure or renal function when RASt was compared with best medical therapy, creating significant concerns about procedural efficacy. In the wake of these randomized trial results, hypertension and renal disease experts along with vascular interventional specialists now struggle with how to best manage atherosclerotic renal artery stenosis. This review objectively analyzes the current literature and highlights each trial's design weaknesses and strengths. We have provided our recommendations for contemporary treatment guidelines based on our interpretation of the available empirical data.

Renal artery stenting may not be appropriate for patients with atherosclerotic renal artery stenosis

INTRODUCTION

This study compared aortorenal bypass to renal artery stenting to determine the most efficacious and financially sound method for treating patients with atherosclerotic renal artery stenosis (RAS).

METHODS

A decision analysis using direct and indirect costs, and value of statistical life (VSL) was completed. Direct costs were obtained using the Nationwide Inpatient Sample (NIS), indirect costs from the National Institute of Diabetes and Digestive and Kidney Diseases, and VSL from the Department of Transportation. A variance-based sensitivity analysis was completed to assess the accuracy of the decision analysis.

RESULTS

Aortorenal bypass has a 95% five-year patency, a 98% 30-day survival, a 26% rate of overall complications, and a 70% five-year dialysis-free survival. Renal artery stenting has a 56% five-year patency, a 99% 30-day survival, a 40% rate of complications, and a 65% five-year dialysis-free survival. Renal artery stenting has an overall cost of $305,370 and aortorenal bypass has an overall cost of $103,453 per patient. After accounting for VSL, renal artery stenting has a negative value of -$182,270 and aortorenal bypass has a value of $415,881.

CONCLUSIONS

Lower five-year patency and higher rate of complications from renal artery stenting that ultimately lead to significantly lower five-year dialysis-free survival.

Renal artery revascularisation can restore kidney function with absent radiotracer uptake

BACKGROUND

Children with renovascular hypertension often present with severe hypertension. Some children have severe obstruction of their renal arteries resulting in <10% relative function on [(99m)Tc]dimercaptosuccinic acid (DMSA) scan. Conventional treatment of these children has been nephrectomy of the poorly functioning kidney to normalise their blood pressure (BP).

CASE-DIAGNOSIS/TREATMENT

We describe three children aged 20 months to 9 years with severe renal artery stenosis and severe hypertension who had radionucleotide uptake of 0% in one kidney. In one case, no renal perfusion was demonstrated by duplex ultrasound scan. Significant recovery of relative renal function of 18 to 52% was achieved after revascularisation by percutaneous angioplasty or open surgery of the obstructed renal artery.

CONCLUSION

These cases illustrate that scintigraphy alone cannot be used to predict salvageable function in children with renovascular disease.

Early duplex predicts restenosis after renal artery angioplasty and stenting

OBJECTIVE

To examine the relationship between early renal duplex sonography (RDS) and restenosis after primary renal artery percutaneous angioplasty and stenting (RA-PTAS).

METHODS

Consecutive patients undergoing RA-PTAS for hemodynamically significant atherosclerotic renal artery stenosis with hypertension and/or ischemic nephropathy between September 2003 and July 2010 were identified from a prospective registry. Patients had renal RDS pre-RA-PTAS, within 1 week of RA-PTAS and follow-up RDS examinations after the first postoperative week for surveillance of restenosis. Restenosis was defined as a renal artery peak systolic velocity (PSV) ≥ 180 cm/s on follow-up RDS. Associations between RDS and restenosis were examined using proportional hazards regression.

RESULTS

Eighty-three patients (59% female; 12% nonwhite; mean age, 70 ± 10 years; mean pre-RA-PTAS PSV, 276 ± 107 cm/s) undergoing 91 RA-PTAS procedures comprised the sample for this study. All procedures included a completion arteriogram demonstrating no significant residual stenosis. Mean follow-up time was 14.9 ± 10.8 months. Thirty-four renal arteries (RAs) demonstrated restenosis on follow-up with a median time to restenosis of 8.7 months. There was no significant difference in the mean PSV pre-RA-PTAS in those with and without restenosis (287 ± 96 cm/s vs 269 ± 113 cm/s; P = .455), and PSV pre-RA-PTAS was not predictive of restenosis. Within 1 week of RA-PTAS, mean renal artery PSV differed significantly for renal arteries with and without restenosis (112 ± 27 cm/s vs 91 ± 34 cm/s; P = .003). Proportional hazards regression analysis demonstrated increased PSV on first post-RA-PTAS RDS was significantly and independently associated with subsequent restenosis during follow-up (hazard ratio for 30 cm/s increase, 1.81; 95% confidence interval, 1.32-2.49; P = .0003). There was no difference in pre- minus postprocedural PSV in those with and without restenosis on follow-up (175 ± 104 cm/s vs 179 ± 124 cm/s; P = .88), nor was this associated with time to restenosis. Best subsets model selection identified first postprocedural RDS as the only factor predictive of follow-up restenosis. A receiver-operating characteristic curve was examined to assess the first week PSV post-RA-PTAS most predictive of restenosis during follow-up. The ideal cut point for RA-PSV was 87 cm/s or greater. This value was associated with a sensitivity of 82.4%, specificity of 52.6%, and area under the receiver-operating characteristic curve of 69.3%. Increased first postprocedural RA-PSV was predictive of lower estimated glomerular filtration rate in the first 2 years after the procedure (-1.6 ± 0.7 mL/min/1.73 m(2) lower estimated glomerular filtration rate per 10 cm/s increase in RA-PSV; P = .010).

CONCLUSIONS

Early renal artery PSV within 1 week after RA-PTAS predicted renal artery restenosis and lower postprocedure renal function. Recurrent stenosis demonstrated no association with absolute elevation in PSV prior to RA-PTAS nor with the change in PSV after RA-PTAS. These data suggest that detectable differences exist in renal artery flow parameters following RA-PTAS that are predictive of restenosis during follow-up but are not apparent on completion arteriography or detectable by intra-arterial pressure measurements. Further study is warranted.

Clinical effect of endovascular treatment on blood pressure and kidney function for hypertensive patients with renal artery stenosis

The objective of this study was to evaluate the clinical effect of endovascular treatment on postoperative blood pressure (BP) control and kidney function of hypertensive patients with renal artery stenosis (RAS). Between January 2004 and December 2011, RAS was diagnosed in 120 renal arteries from 115 hypertensive patients. Preoperative and postoperative BPs and glomerular filtration rate (GFR) were monitored. Postoperative oral antiplatelet and antihypertensive agents were administered. Clinical follow-up was available for all patients for at least 6 months. Balloon angioplasty was performed successfully in 110 patients, and stents were deployed in 94 renal arteries from 89 patients. Hypertension was cured and lessened in 19 and 61 patients, respectively. Blood pressure was stable and worsened in 26 and 9 patients, respectively. The renal function was improved and stable in 23 patients and 57 patients, respectively. Deterioration of renal function was observed in 11 patients. Doppler ultrasound after discharge revealed 87 patent renal arteries and fixed stents in 82 patients 6 months after procedure. Balloon angioplasty and stent deployment are effective and feasible procedures for patients with RAS that help in controlling BP and improving renal function moderately.

Successful percutaneous revascularization in a patient with a chronic totally occluded renal artery in an atrophied kidney

A 57-year-old man presented with renovascular hypertension with chronic kidney disease. 16-Multi-detector row computed tomography (MDCT) showed that the left renal artery was totally occluded and the left kidney was atrophied. The left atrophied kidney was hormonally active despite the desolation of glomerular filtration function. Percutaneous renal revascularization was successful for stenting this lesion. The renin activity in the left renal vein was decreased immediately after the procedure. He remained healthy with adequate blood pressure for three years. In this case, MDCT and renal vein renin measurement provided useful information for the decision to perform percutaneous renal revascularization.

Predicting blood pressure response after renal artery stenting

BACKGROUND

Although technical success of renal artery stenting (RAS) is high and adverse events are infrequent, clinical success (improved blood pressure and renal function) and durability have been less predictable. Identifying those patients who will respond to RAS could improve overall outcomes of the procedure.

METHODS

This was a retrospective analysis of all patients who underwent RAS for treatment of renovascular hypertension (RVH) between 2001 and 2007 at Dartmouth-Hitchcock Medical Center. The primary outcome measure was blood pressure improvement or cure as judged by American Heart Association criteria. Estimated glomerular filtration rate (eGFR), number of antihypertensive medications, and survival were evaluated as secondary outcomes. Univariate and multivariate analyses were performed to identify factors associated with blood pressure improvement at the last follow-up.

RESULTS

During the 6-year period, 129 patients (179 renal arteries) underwent stent placement for RVH. Procedural complications occurred nine patients (7.0%). Average length follow-up was 1.5 years. Follow-up data were obtained in 122 patients (95%). At last follow-up, there were significant improvements in systolic blood pressure (161 vs 144 mm Hg, P < .001), diastolic blood pressure (80 vs 73 mm Hg, P < .001), and number of antihypertensive medications (3.1 vs 2.8, P = .034). The eGFR was improved in 16% of patients, stable in 60%, and worse in 24%. By multivariate analysis, a baseline eGFR <40 mL/min/1.73 m2 (odds ratio, 1.6; 95% confidence interval [CI], 1.0-2.9; P = .02) and female gender (OR, 1.3; 95% CI, 1.0-2.1; P = .04) were independent predictors of failure to achieve blood pressure improvement. By 2 and 4 years of follow-up, sustained blood pressure improvement was present in 67% of patients with a baseline eGFR of > or = 40 mL/min/1.73 m2 and in 31% of patients with a baseline eGFR <40 mL/min/1.73 m2. During 2 years of follow-up, survival was similar between patients with sustained blood pressure response and those without.

CONCLUSION

Patients treated for RVH who have a baseline eGFR of > or = 40 mL/min/1.73 m2 demonstrate a better response to RAS at each follow-up interval, with a significant difference at 2 to 4 years, compared with patients with an eGFR <40 mL/min/1.73 m2.

Restenosis after renal artery angioplasty and stenting: incidence and risk factors

BACKGROUND

Management of renal artery stenosis (RAS) with primary renal artery percutaneous angioplasty and stenting (RA-PTAS) is associated with a low risk of periprocedural death and major complications; however, restenosis develops in a subset of patients and repeat intervention may be required. We examined the incidence of restenosis after RA-PTAS and associations with clinical factors.

METHODS

Consecutive patients undergoing RA-PTAS for hemodynamically significant atherosclerotic RAS associated with hypertension or ischemic nephropathy, or both, between October 2003 and September 2007 were identified from a registry. Restenosis was defined using duplex ultrasound (DUS) imaging as a renal artery postintervention peak systolic velocity (PSV) >or=180 cm/s. The incidence and temporal distribution of restenosis was analyzed using survival analysis based on treated kidneys. Associations between clinical factors and recurrent stenosis were examined using proportional hazards regression.

RESULTS

RA-PTAS was performed on 112 kidneys for atherosclerotic RAS during the study period. Initial postintervention renal artery DUS imaging confirming PSV <180 cm/s in 101 kidneys, which formed the basis of this analysis. Estimated restenosis-free survival was 50% at 12 months and 40% at 18 months. Decreased risk of restenosis was associated with preoperative statin use (hazard ratio [HR], 0.35; 95% confidence interval [CI], 0.16-0.74; P = .006) and increased preoperative diastolic blood pressure (DBP; HR, 0.70 per 10-mm Hg increase in preoperative DBP; 95% CI, 0.49-0.99; P = .049). No other factors assessed were associated with restenosis.

CONCLUSION

Restenosis occurs in a substantial number of patients treated with RA-PTAS. Preoperative statin medication use and increased preoperative DBP are associated with reduced risk of restenosis. In the absence of contraindications, statins should be considered standard therapy for patients with atherosclerotic renal artery stenosis.