Mortality and Renal Replacement Therapy after Renal Artery Stent Placement for Atherosclerotic Renovascular Disease

The Maintained Glycemic Target Goal and Renal Function Are Associated with Cardiovascular and Renal Outcomes in Diabetic Patients Following Stent-Supported Angioplasty for Renovascular Atherosclerotic Disease

Patients with type 2 diabetes mellitus (T2DM) constitute a large proportion of patients with atherosclerotic renal artery stenosis (ARAS). However, the mechanism of impaired renal function and hypertension in this subset of patients is multifactorial. We aimed to investigate whether, in diabetic patients, renal function (RF), systolic (SBP) and diastolic blood pressure (DBP) values following stent-supported angioplasty (PTA) for ARAS have an impact on cardiovascular and renal outcomes. Methods: The study group included 93 patients with T2DM and resistant hypertension who underwent PTA for ARAS. The pre- and post-procedure (6 to 12, and 24 months) values of SBP, DBP, eGFR and glycaemia were obtained. The prospective follow-up of median 44 months was performed for combined outcome: major cardiac and cerebral events (MACCE) and progression to renal replacement therapy (RRT). Results: MACCE-RRT occurred in 46 (49.5%) patients, with higher incidence in patients with higher values of SBP (147.8 ± 25.8 vs. 136.7 ± 15.8 mmHg, p = 0.006), DBP (80.8 ± 13.3 vs. 74.4 ± 12.3 mmHg, p = 0.009), chronic kidney disease in stages 3B to 5 (p = 0.029) and those who have not obtained target glycemic goals compared to well-maintained T2DM (p = 0.007) at 24-months. On multivariate Cox analysis, well-maintained T2DM targets [Hazard Ratio (HR):0.27; 95% Confidence Interval (CI):0.13−0.57; p < 0.001], eGFR below 45 mL/min/m2 (HR: 2.20; 95%CI: 1.20−4.04; p = 0.011), previous stroke (HR:2.52; 95%CI:1.19−5.34; p = 0.015) retained their associations with MACCE-RRT, while BP values were not associated with the outcome. Conclusions: The post-procedural RF, maintained glycemic target goal and previous stroke are vital for the outcome in patients undergoing PTA for renovascular disease in diabetic patients.

Long-Term Mortality After Renal Artery Stenting in Patients With Severe Atherosclerotic Renal Artery Stenosis and High-Risk Clinical Manifestations

BACKGROUND

Atherosclerotic renal artery stenosis is a risk factor for cardiovascular death. Observational studies support the benefit of renal revascularization on outcomes in patients with high-risk clinical manifestations. In this context, we evaluated the factors associated with long-term mortality after renal artery stenting in patients with severe renal artery stenosis, impaired kidney function, and/or uncontrolled hypertension.

METHODS

The medical records of patients undergoing renal artery stenting between 2004 and 2014 were extracted. Blood pressure and creatinine were recorded at baseline, 24 hours poststenting and in the 1-month to 1-year interval that followed revascularization. Long-term follow-up was performed in March 2020.

RESULTS

The cohort consisted of 65 patients. Median follow-up was 120 months. In the first year after stenting, less patients had chronic kidney disease (CKD) class 3b-5 as compared with baseline (35.3% vs. 56.9%, P = 0.01). The number of patients with controlled blood pressure after revascularization increased with 69.2% (P < 0.001). Long-term all-cause mortality reached 44.6%. Age (odds ratio (OR) 1.1; 95% confidence interval (CI) 1.0-1.2; P = 0.01), male gender (OR 7.9; 95% CI 1.9-43.5; P = 0.008), poststenting CKD class 3b-5 (OR 5.8; 95% CI 1.5-27.9; P = 0.01), and postrevascularization uncontrolled hypertension (OR 8.9; 95% CI 1.7-63.5; P = 0.01) were associated with long-term mortality independent of diabetes mellitus and coronary artery disease.

CONCLUSIONS

Improved CKD class and blood pressure were recorded in the first year after renal artery stenting in patients with severe renal artery stenosis and high-risk clinical manifestations. The lack of improvement in kidney function and blood pressure was independently associated with long-term mortality.

Determinant role of renal artery stenting in recovery from acute worsening of atherosclerotic renal failure

Because previous randomized clinical trials have failed to show any benefits of renal artery stenting (RAS), clinicians have been confused regarding the optimal management of patients with atherosclerotic renal artery stenosis (ARAS). Here, we report a notable case with ARAS whose clinical course could help clinicians identify patients suitable for RAS. A 66-year-old woman with ARAS and some parameter abnormalities on renal duplex ultrasound was admitted to our hospital with severe hypertension (>250 mmHg). After the initiation of antihypertensive intravenous treatment, the patient manifested acute worsening of renal function over 6 days and required dialysis. Because renal failure continued to deteriorate over more than 4 weeks, we performed stenting to the severe ostial stenosis of the right renal artery. As a result, the patient achieved dramatic improvement in renal function and successful withdrawal from dialysis and has maintained stable control of blood pressure without additional events for more than 2 years since discharge. This case suggests that careful analysis of the patient's profile, such as history of rapidly deteriorating renal failure, presence of bilateral ARAS, or a solitary functional kidney, in addition to various parameters of renal duplex ultrasound, may help predict the efficacy of RAS in patients with ARAS.

<Learning objective: Because several randomized studies have reported negative results for renal artery stenting (RAS), an individual-based approach is required for the treatment of atherosclerotic renal artery stenosis (ARAS). To determine whether RAS could be effective in patients with ARAS, it is important to assess patient-specific characteristics such as progression of renal failure (e.g. acute worsening), presence of bilateral ARAS, or the existence of a solitary functional kidney, as well as parameters of related examinations such as the renal arterial resistive index.>

Carotid intraplaque neovascularization predicts atherosclerotic renal artery stenosis in patients with carotid artery stenosis

BACKGROUND AND AIMS

This study aimed to examine whether intraplaque neovascularization (IPN) of carotid plaques, as characterized by contrast-enhanced ultrasound (CEUS), is associated with atherosclerotic renal artery stenosis (ARAS) in patients with normal kidney function.

METHODS AND RESULTS

We investigated carotid IPN using CEUS in 198 consecutive patients with normal kidney function with and without ARAS. IPN was graded on the basis of the presence and location of microbubbles within each plaque (0, no visible microbubbles in the plaque; 1, moderate microbubbles confined to the shoulder and/or adventitial side of the plaque; and 2, extensive microbubbles throughout the plaque). The grades of each plaque were averaged to obtain an overall score per patient. ARAS was determined angiographically. We found that a higher CEUS-assessed carotid IPN score was associated with ARAS (Odd Ratio, OR: 7.281; 95% Confidence Interval, 95% CI: 3.246-16.336; P < 0.001). Furthermore, an IPN score >1.75 predicted severe stenosis with a sensitivity of 81% and specificity of 58%. Compared with using the IPN score alone, the addition of the homocysteine (HCY) cutoff value (>22.5 mmol/L) resulted in a stronger predictive value (Area Under Curve, AUC: 0.893 vs 0.834; P < 0.001) for severe ARAS.

CONCLUSION

Carotid plaque neovascularization combined with HCY levels is predictive of severe ARAS in patients with normal kidney function. CEUS-assessed carotid IPN is clinically useful for stratification of ARAS in patients with normal kidney function.

The Role of Hypoxia in Ischemic Chronic Kidney Disease

A gradually developing reduction in renal blood flow from atherosclerotic renovascular disease results in loss of kidney volume and a decrease in glomerular filtration rate that eventually becomes irreversible. Whether this process fundamentally reflects tissue hypoxia has been difficult to establish. Studies of human renovascular disease have indicated that reductions in blood flow of up to 30% to 40% can be tolerated with preservation of normal oxygenation and structural integrity. These observations are consistent with remarkable stability of poststenotic kidney function during sustained medical antihypertensive drug therapy in moderate renovascular disease. With more severe and sustained reductions, however, cortical oxygenation decreases and the magnitude of medullary hypoxia expands. These changes are associated with increasing renal venous levels of inflammatory cytokines, angiogenic markers, and infiltration of inflammatory cells, including tissue macrophages and T cells. Although restoring large-vessel blood flow can improve oxygenation, some of these processes reflect microvascular rarefication, remain activated, and do not depend on hemodynamic factors alone. Elucidation of tissue injury pathways associated with hypoxia opens the possibility of adjunctive therapeutic measures beyond renal revascularization. These include cell-based regeneration, mitochondrial protection, and/or angiogenic cytokine therapy to restore or preserve renal function in ischemic nephropathy.

Microvascular Disease Increases Amputation in Patients With Peripheral Artery Disease

It is estimated that >2 million patients are living with an amputation in the United States. Peripheral artery disease (PAD) and diabetes mellitus account for the majority of nontraumatic amputations. The standard measurement to diagnose PAD is the ankle-brachial index, which integrates all occlusive disease in the limb to create a summary value of limb artery occlusive disease. Despite its accuracy, ankle-brachial index fails to well predict limb outcomes. There is an emerging body of literature that implicates microvascular disease (MVD; ie, retinopathy, nephropathy, neuropathy) as a systemic phenomenon where diagnosis of MVD in one capillary bed implicates microvascular dysfunction systemically. MVD independently associates with lower limb outcomes, regardless of diabetic or PAD status. The presence of PAD and concomitant MVD phenotype reveal a synergistic, rather than simply additive, effect. The higher risk of amputation in patients with MVD, PAD, and concomitant MVD and PAD should prompt aggressive foot surveillance and diagnosis of both conditions to maintain ambulation and prevent amputation in older patients.

Comparison of Percutaneous Transluminal Angioplasty with Stenting for Treatment of Central Venous Stenosis or Occlusion in Hemodialysis Patients: A Systematic Review and Meta-analysis

OBJECTIVES

A common cause of hemodialysis vascular access dysfunction, a primary cause of morbidity and mortality in patients undergoing hemodialysis, is central venous stenosis or occlusion. The present study compared percutaneous transluminal angioplasty (PTA) with percutaneous transluminal angioplasty and stent placement (PTS) for treatment of central venous stenosis or central vein occlusion in hemodialysis patients.

METHODS

A systematic literature review was conducted using database searches of PubMed, Cochrane, and Embase. Articles were selected using the Population/Intervention/Comparator/Outcomes (PICO) process. Outcomes included the rate of procedural success, primary patency, assisted primary patency, re-intervention subjects, re-intervention rate, and adverse events.

RESULTS

A total of eight studies were included in the meta-analysis with subjects in the PTA group (n = 281) or PTS group (n = 192). Primary patency rate between PTA and PTS groups at 3-, 6-, 12-, or 24-month follow-up was not different (all p > 0.05). Patients treated with PTA had greater assisted primary patency rates than the PTS group (OR = 1.03, 1.73, 1.03, and 2.00 at 3, 6, 12, and 24 months, respectively). However, the statistical assessment only showed significantly at 24-month follow-up (p = 0.01).

CONCLUSIONS

The present meta-analysis revealed that, compared to PTS, PTA may provide increased assisted primary patency for endovascular treatment of central vein stenosis or occlusion in patients undergoing hemodialysis.

LEVEL OF EVIDENCE

Level 3a.

Impact of Renal Function Trajectory on Renal Replacement Therapy and Mortality Risk after Renal Artery Revascularization

PURPOSE

To determine the impact of renal function trajectory, defined as the change in renal function over time before and after renal artery stent placement, on long-term risk for renal replacement therapy (RRT) and mortality.

MATERIALS AND METHODS

Estimated glomerular filtration rates (eGFRs) 6-12 months before renal artery stent placement, at the time of intervention, and 6-12 months after intervention were determined in 398 patients. The effect of eGFR change before and after renal artery stent placement was calculated. Cox proportional-hazards ratio was used to determine the risks for RRT and all-cause mortality.

RESULTS

The risk for RRT was significantly influenced by eGFR change from the time of intervention to follow-up at 6-12 month after treatment (P = .02). In addition, among patients with a postintervention eGFR ≤ 40 mL/min/1.73 m², for every 1 unit of eGFR increase, there was a significant decrease in RRT and all-cause mortality (P < .001 and P < .001, respectively). Secondary parameters that increased RRT risk included diabetes at the time of intervention (P = .03), increased baseline proteinuria (P < .001), and stage 4 or 5 chronic kidney disease (CKD; P = .01 and P = .003, respectively). Multivariate analysis demonstrated higher all-cause mortality rates among patients with diabetes at the time of intervention (P = .009).

CONCLUSIONS

Postintervention eGFR trajectory improvement approaching 40 mL/min/1.73 m² was associated with decreased RRT and mortality risk. These findings suggest that patients with advanced CKD and renal artery stenosis may benefit from revascularization regardless of their preinterventional renal function measurement.

Restenosis Rates After Drug-Eluting Stent Treatment for Stenotic Small-Diameter Renal Arteries

PURPOSE

To determine primary rates in small-diameter renal arteries, including complex bifurcation lesions, treated with drug-eluting stents (DES) in patients with atherosclerotic renal artery stenosis.

MATERIALS AND METHODS

This is a retrospective single-institution study. A total of 37 patients with 39 stented renal arteries were included. Patient and procedural data were obtained from the electronic medical record. Survival free from restenosis was estimated using the Kaplan-Meier method with patients stratified into two groups based on renal artery diameters (≤ 3.5 mm or > 3.5 mm). Univariate Cox proportional models were used to estimate hazard ratios associated with clinical and angiographic variables.

RESULTS

Average renal artery diameter at time of treatment was 3.4 mm ± 0.4 mm. The median survival free from restenosis was 992 days, with 11 out of 37 (29.7%) developing an in-stent restenosis. Renal arteries < 3.5 mm in diameter had similar patency rates as renal arteries > 3.5 mm (P = 0.33). The 1-, 2-, and 5-year patency rates were 71%, 63%, and 38%, respectively. History of stroke was the only comorbidity to portend a significantly greater rate of restenosis (hazard ratio 3.77; 95%CI, 1.05-13.6; P = 0.04). Medications did not statistically alter the risk of restenosis.

CONCLUSION

Revascularization of renal arteries with DES achieved similar primary patency rates irrespective of renal artery diameter. Stent configuration was not associated with time to renal replacement therapy or all-cause mortality.

LEVEL OF EVIDENCE

Level 3, Cohort Study.

Total Renal Artery Occlusion: Recovery of Function After Revascularization

Current trends in managing atherosclerotic renal artery stenosis favor medical therapy, on account of negative results from prospective trials of revascularization, such as CORAL and ASTRAL. One result of this trend has been encountering occasional patients with progressive disease, sometimes leading to total arterial occlusion. We illustrate a case of accelerated hypertension with complete renal artery occlusion in which the patient recovered function after surgical bypass and we review the clinical approach used and the advanced imaging modalities available to us. A high index of suspicion and careful radiologic imaging play important roles in selecting patients who may have residual function and may benefit from revascularization. This case illustrates an example whereby restoring renal artery perfusion for carefully selected patients can be life changing, with recovery of kidney function and improved blood pressure, pill burden, and overall quality of life.

Current Concepts in the Treatment of Renovascular Hypertension

Renovascular disease (RVD) remains a major cause of secondary and treatment-resistant hypertension. Most cases are related either to fibromuscular or atherosclerotic lesions, but a variety of other causes including arterial dissection, stent occlusion, and embolic disease can produce the same syndrome. Recent studies emphasize the kidney's tolerance to moderate flow reduction during antihypertensive drug therapy and the relative safety of medical therapy to control blood pressure. Several prospective trials in moderate RVD fail to identify major benefits from endovascular revascularization for moderate atherosclerotic disease. However, high-risk and progressive renovascular syndromes are recognized to be relatively refractory to medical therapy only and respond better to combining renal revascularization with ongoing medical therapy. Clinicians caring for complex hypertension should be familiar with pathogenic pathways, imaging techniques, and a rational approach to managing renovascular hypertension in the current era.

Primary Prevention of Stroke in Chronic Kidney Disease Patients: A Scientific Update

BACKGROUND

Although chronic kidney disease (CKD) is an independent risk factor for stroke, official recommendations for the primary prevention of stroke in CKD are generally lacking.

SUMMARY

We searched PubMed and ISI Web of Science for randomised controlled trials, observational studies, reviews, meta-analyses and guidelines referring to measures of stroke prevention or to the treatment of stroke-associated risk factors (cardiovascular disease in general and atrial fibrillation (AF), arterial hypertension or carotid artery disease in particular) among the CKD population. The use of oral anticoagulation in AF appears safe in non-end stage CKD, but it should be individualized and preferably based on thromboembolic and bleeding stratification algorithms. Non-vitamin K antagonist oral anticoagulants with definite dose adjustment are generally preferred over vitamin K antagonists in mild and moderate CKD and their indications have started being extended to severe CKD and dialysis also. Aspirin, but not clopidogrel, has limited indications for reducing the risk for atherothrombotic events in CKD due to its increased bleeding risk. Carotid endarterectomy has shown promising results for stroke risk reduction in CKD patients with high-grade symptomatic carotid stenosis. The medical treatment of arterial hypertension in CKD often fails to efficiently lower blood pressure values, but recent data regarding the use of interventional procedures such as renal denervation, baroreflex activation therapy or renal artery stenting are encouraging. Key Messages: In the absence of clear guidelines and protocols, primary prevention of stroke in CKD patients remains a subtle art in the hands of the clinicians. Nevertheless, refraining CKD patients from standard therapies often worsens their prognosis.