Selection of Patients for Angioplasty for Treatment of Atherosclerotic Renovascular Disease: Predicting Responsive Patients

CT-based radiomics: predicting early outcomes after percutaneous transluminal renal angioplasty in patients with severe atherosclerotic renal artery stenosis

This study aimed to comprehensively evaluate non-contrast computed tomography (CT)-based radiomics for predicting early outcomes in patients with severe atherosclerotic renal artery stenosis (ARAS) after percutaneous transluminal renal angioplasty (PTRA). A total of 52 patients were retrospectively recruited, and their clinical characteristics and pretreatment CT images were collected. During a median follow-up period of 3.7 mo, 18 patients were confirmed to have benefited from the treatment, defined as a 20% improvement from baseline in the estimated glomerular filtration rate. A deep learning network trained via self-supervised learning was used to enhance the imaging phenotype characteristics. Radiomics features, comprising 116 handcrafted features and 78 deep learning features, were extracted from the affected renal and perirenal adipose regions. More features from the latter were correlated with early outcomes, as determined by univariate analysis, and were visually represented in radiomics heatmaps and volcano plots. After using consensus clustering and the least absolute shrinkage and selection operator method for feature selection, five machine learning models were evaluated. Logistic regression yielded the highest leave-one-out cross-validation accuracy of 0.780 (95%CI: 0.660-0.880) for the renal signature, while the support vector machine achieved 0.865 (95%CI: 0.769-0.942) for the perirenal adipose signature. SHapley Additive exPlanations was used to visually interpret the prediction mechanism, and a histogram feature and a deep learning feature were identified as the most influential factors for the renal signature and perirenal adipose signature, respectively. Multivariate analysis revealed that both signatures served as independent predictive factors. When combined, they achieved an area under the receiver operating characteristic curve of 0.888 (95%CI: 0.784-0.992), indicating that the imaging phenotypes from both regions complemented each other. In conclusion, non-contrast CT-based radiomics can be leveraged to predict the early outcomes of PTRA, thereby assisting in identifying patients with ARAS suitable for this treatment, with perirenal adipose tissue providing added predictive value.

Correlation of renal cortical blood perfusion and BP response after renal artery stenting

Background

This study aimed to observe the correlation between renal cortical blood perfusion (CBP) parameters and BP response in patients with severe renal artery stenosis (RAS) who underwent stenting.

Methods

This was a single-center retrospective cohort study. A total of 164 patients with unilateral severe RAS after successful percutaneous transluminal renal artery stenting in Beijing Hospital from October 2017 to December 2020 were included. According to the results of BP evaluated at 12 months, all patients were divided into the BP response group (n = 98) and BP nonresponse group (n = 66). The baseline clinical and imaging characteristics and follow-up data about 24 h ABPM and CBP were recorded and analyzed. Pearson correlation analysis was used to evaluate the relationship between CBP parameters and 24 h average SBP. Univariate and multivariate logistic regression analysis was used to evaluate the risk factors for BP response.

Results

Among 164 patients with severe RAS, there were 100 males (61.0%), aged 37–75 years, with an average of 56.8 ± 18.4 years, and average artery stenosis of 84.0 ± 12.5%. The BP nonresponse patients had a longer duration of hypertension, more current smoking subjects and diabetic patients, lower eGFR, increased number of hypertensive agents, and rate of insulin compared with the BP response group (P < 0.05). After PTRAS, patients in the BP response group were associated with significantly lower BP and improved CPB, characterized by increased levels of maximum intensity (IMAX), area under ascending curve (AUC1), area under the descending curve (AUC2), shortened rising time (RT), mean transit time (mTT), and prolonged time to peak intensity (TTP; P < 0.05). However, the BP nonresponse group was only associated with significantly reduced RT (P < 0.05) compared with baseline data. During an average follow-up of 11.5 ± 1.7 months, the BP response group was associated with significantly lower levels of SBP, DBP, 24 h average SBP, and 24 h average DBP compared with the nonresponse group (P < 0.05). Pearson correlation analysis showed that the the pre-operative CBP parameters, including IMAX (r = 0.317), RT (r = 0.249), AUC1 (r = 0.614), AUC2 (r = 0.558), and postoperative CBP parameters, including RT (r = 0.283), AUC1 (r = 0.659), and AUC2 (r = 0.674) were significantly positively correlated with the 24 h average SBP, while the postoperative TTP (r = −0.413) and mTT (r = −0.472) were negatively correlated with 24 h average SBP (P < 0.05). Multivariate Logistic regression analysis found that diabetes (OR = 1.294), NT-proBNP (OR = 1.395), number of antihypertensive agents (OR = 2.135), pre-operation IMAX (OR = 1.534), post-operation AUC2 (OR = 2.417), and baseline dDBP (OR = 2.038) were related factors for BP response (all P < 0.05).

Conclusion

Patients in the BP nonresponse group often have diabetes, a longer duration of hypertension, significantly reduced glomerular filtration rate, and heavier renal artery stenosis. CBP parameters are closely related to 24 h average SBP, and pre-operation IMAX and post-operation AUC2 are markers for a positive BP response.

Revascularization for Renovascular Disease: A Scientific Statement From the American Heart Association

Renovascular disease is a major causal factor for secondary hypertension and renal ischemic disease. However, several prospective, randomized trials for atherosclerotic disease failed to demonstrate that renal revascularization is more effective than medical therapy for most patients. These results have greatly reduced the generalized diagnostic workup and use of renal revascularization. Most guidelines and review articles emphasize the limited average improvement and fail to identify those clinical populations that do benefit from revascularization. On the basis of the clinical experience of hypertension centers, specialists have continued selective revascularization, albeit without a summary statement by a major, multidisciplinary, national organization that identifies specific populations that may benefit. In this scientific statement for health care professionals and the public-at-large, we review the strengths and weaknesses of randomized trials in revascularization and highlight (1) when referral for consideration of diagnostic workup and therapy may be warranted, (2) the evidence/rationale for these selective scenarios, (3) interventional and surgical techniques for effective revascularization, and (4) areas of research with unmet need.

Dynamic changes of renal cortical blood perfusion before and after percutaneous transluminal renal artery stenting in patients with severe atherosclerotic renal artery stenosis

BACKGROUND

This study aims to observe the dynamic changes of renal artery (RA) disease and cortical blood perfusion (CBP) evaluated by contrast-enhanced ultrasound (CEUS) after percutaneous transluminal renal artery stenting (PTRAS) in patients with severe atherosclerotic renal artery stenosis (ARAS) and to analyze the relationship between CBP and prognosis.

METHODS

This was a single-center retrospective cohort study. A total of 98 patients with unilateral severe ARAS after successful PTRAS in Beijing Hospital from September 2017 to September 2020 were included. According to renal glomerular filtration rate (GFR) detected by radionuclide imaging at 12 months after PTRAS, all patients were divided into the poor prognosis group (n = 21, GFR decreased by ≥20% compared with baseline) and the control group (n = 77, GFR decreased by < 20% or improved compared with baseline). Renal artery stenosis was diagnosed by digital subtraction angiography, and renal CBP was evaluated by CEUS using TomTec Imaging Systems (Germany) before PTRAS, at 6 months and 12 months after discharge. The receiver operating characteristic (ROC) curve with area under the curve (AUC) was used to analyze the predictive value of CBP parameters, including area under ascending curve (AUC1), area under the descending curve (AUC2), rising time (RT), time to peak intensity (TTP), maximum intensity (IMAX), and mean transit time (MTT) for poor prognosis.

RESULTS

Among the 98 patients, there were 52 males (53.1%), aged 55-74 years old, with an average age of 62.1 ± 8.7 years, and an average artery stenosis of 82.3 ± 12.9%. The poor prognosis group was associated with significantly increased incidence of diabetes (76.2% vs. 41.6%), and lower levels of GFR of the stenotic kidney (21.8 mL/min vs. 25.0 mL/min) and total GFR (57.6 mL/min vs. 63.7 mL/min) (all P < 0.05), compared with the control group (P < 0.05). In addition, the rate of RA restenosis was significantly higher in the poor prognosis group than in the control group (9.5% vs. 0, χ2 = 9.462, P = 0.002). Compared with the control group, the poor prognosis group was associated with significantly decreased baseline AUC1 and AUC2, and extended duration of TTP and MTT (P < 0.05). At 6 months and 12 months of follow-up, patients in the control group were associated with markedly increased AUC1, AUC2, and IMAX, and shorter duration of RT and MTT (P < 0.05). The ROC curve showed that the predictive values of AUC1, AUC2, RT, TTP, IMAX, and MTT for poor prognosis were 0.812 (95% CI: 0.698-0.945), 0.752 (95% CI: 0.591-0.957), 0.724 (95% CI: 0.569-0.961), 0.720 (95% CI: 0.522-0.993), 0.693 (95% CI: 0.507-0.947), and 0.786 (95% CI: 0.631-0.979), respectively.

CONCLUSIONS

Preoperative renal CBP in severe ARAS patients with poor prognosis is significantly reduced, and does not show significant improvement after stent treatment over the first year of follow-up. The parameter AUC1 may be a good predictor for renal dysfunction after PTRAS in severe ARAS patients. Trial Registration: ChiCTR.org.cn, ChiCTR1800016252.

Renal Artery Revascularization a controversial treatment strategy for Renal Artery Stenosis. A case series and a brief review of current literature

Renal artery stenosis (RAS) may cause secondary hypertension, progressive decline in renal function, and cardiac destabilization syndromes including "flash" pulmonary edema, recurrent congestive heart failure, and cerebro-cardiovascular disease. Atherosclerotic lesions, fibromuscular dysplasia and vasculitides are the pathophysiologic basis of the disease. Common therapeutic pathways for RAS include medical therapy and revascularization with or without stenting. Randomized controlled trials evaluating renal revascularization, did not report any advantage of revascularization over medical therapy alone in terms of renal function improvement or prevention of cardiovascular events. However, mounting clinical experience suggests that the best strategy in RAS management is identifying which patients are most likely to benefit from renal artery stenting and also optimizing the safety and durability of the procedure. This review presents 3 cases of patients who undergone renal revascularization and discusses the available clinical evidence for identification of RAS patients who will potentially respond well to revascularization.

Renal Artery Stenting in Consecutive High-Risk Patients With Atherosclerotic Renovascular Disease: A Prospective 2-Center Cohort Study

Background

The aim of this study was to prospectively evaluate the effects of renal artery stenting in consecutive patients with severe atherosclerotic renal artery stenosis and high‐risk clinical presentations as defined in a national protocol developed in 2015.

Methods and Results

Since the protocol was initiated, 102 patients have been referred for revascularization according to the following high‐risk criteria: severe renal artery stenosis (≥70%) with true resistant hypertension, rapidly declining kidney function, or recurrent heart failure/sudden pulmonary edema. At baseline, the mean 24‐hour ambulatory systolic blood pressure was 166.2 mm Hg (95% CI, 162.0–170.4), the defined daily dose of antihypertensive medication was 6.5 (95% CI, 5.8–7.3), and the estimated glomerular filtration rate was 41.1 mL/min per 1.73m² (95% CI, 36.6–45.6). In 96 patients with available 3‐month follow‐up data, mean 24‐hour ambulatory systolic blood pressure decreased by 19.6 mm Hg (95% CI, 15.4–23.8; P<0.001), the defined daily dose of antihypertensive medication was reduced by 52% (95% CI, 41%–62%; P<0.001), and estimated glomerular filtration rate increased by 7.8 mL/min per 1.73m² (95% CI, 4.5–11.1; P<0.001). All changes persisted after 24 month follow‐up. Among 17 patients with a history of hospitalization for acute decompensated heart failure, 14 patients had no new episodes after successful revascularization.

Conclusions

In this prospective cohort study, we observed a reduction in blood pressure and antihypertensive medication, an increase in estimated glomerular filtration rate, and a decrease in new hospital admissions attributable to heart failure/sudden pulmonary edema after renal artery stenting.

Registration

URL: https://clinicaltrials.gov. Identifier: NCT02770066.

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.

Treatment of Refractory Hypertension with Timely Angioplasty in Total Renal Artery Occlusion with Atrophic Kidney

Angioplasty for cases of chronic total occlusion of renal artery with/without atrophic kidney is generally not recommended. We herein report a 57-year-old man who presented with renin-mediated refractory hypertension caused by occlusion of a unilateral renal artery leading to kidney atrophy (length: 69 mm). Angioplasty favorably achieved blood pressure control with normalized renin secretion and enlargement of the atrophic kidney to 85 mm. Timely angioplasty can be beneficial in select patients, even with an atrophic kidney and total occlusion, especially in cases with deterioration of hypertension within six months and the presence of collateral perfusion to the affected kidney.

Contrast-Enhanced Ultrasound Assessment of Renal Parenchymal Perfusion in Patients with Atherosclerotic Renal Artery Stenosis to Predict Renal Function Improvement After Revascularization

Background

Identifying patients with atherosclerotic renal artery stenosis (ARAS) who will be improved in renal function after percutaneous transluminal renal artery stenting (PTRAS) is crucial since most patients show no worthwhile benefit of PTRAS. Although the assessment of renal parenchymal perfusion is useful for the identification, few studies predict the renal functional improvement by evaluating the characteristics of renal perfusion.

Objective

The aim of this study was to assess the renal parenchymal perfusion in ARAS patients with contrast-enhanced ultrasonography (CEUS) and predict the benefits of renal function after PTRAS utilizing time-intensity curve (TIC) parameters.

Methods

Thirty-eight kidneys in 30 ARAS patients received PTRAS in this study. They were divided into moderate stenosis group (n=25) and severe stenosis group (n=13) and mild dysfunction group (n=14) and moderate dysfunction group (n=24) according to the degree of renal stenosis and radioisotope glomerular filtration rate (rGFR). The baseline assessment of renal function and renal parenchymal perfusion were performed for all patients. rGFR was repeated to evaluate the renal outcome at 4 months after PTRAS. The outcome of PTRAS was classified as improved, stable, or deteriorated compared to the baseline. Time-intensity curve (TIC) parameters obtained from CEUS were analyzed to evaluate the predictive accuracy.

Results

TIC parameters (AUC and PI) were positively correlated with renal function (r=0.617, 0.663; P<0.05) but weakly and negatively correlated with the stenosis (r=−0.360, −0.435; P<0.05). Baseline rGFR was not accurate in predicting improved renal function after PTRAS (0.670). The accuracy of the combined prediction model of baseline AUC and PI (0.889) was higher than the individual indicators (baseline AUC: 0.855 and PI: 0.782).

Conclusion

CEUS could accurately assess renal parenchymal perfusion and identify ARAS patients with potential benefit after PTRAS. The combination of TIC parameters (AUC and PI) is valuable in the prediction of improved renal function after PTRAS.

How should we define appropriate patients for percutaneous transluminal renal angioplasty treatment?

Renovascular hypertension (RVH) is one of the most common causes of secondary hypertension and can result in resistant hypertension. RVH is associated with an increased risk for progressive decline in renal function, cardiac destabilization syndromes including "flash" pulmonary edema, recurrent congestive heart failure, and cerebrocardiovascular disease. The most common cause of renal artery stenosis (RAS) is atherosclerotic lesions, followed by fibromuscular dysplasia. The endovascular technique of percutaneous transluminal renal angioplasty (PTRA) with or without stenting is one of the standard treatments for RAS. Randomized controlled trials comparing medical therapy with PTRA to medical therapy alone have failed to show a benefit of PTRA; however, the subjects of these randomized clinical trials were limited to atherosclerotic RAS patients, and patients with the most severe RAS, who would be more likely to benefit from PTRA, might not have been enrolled in these trials. This review compares international guidelines related to PTRA, reevaluates the effects of PTRA treatment on blood pressure and renal and cardiac function, discusses strategies for the management of RVH patients, and identifies factors that may predict which patients are most likely to benefit from PTRA.

Kidney enlargement effect of angioplasty for nonatherosclerotic renovascular disease: reversibility of ischemic kidney

Renal artery stenosis causes kidney ischemia, reducing the size of the affected kidney, which eventually results in atrophy. Although renal atrophy is considered irreversible, resolution of the ischemia occasionally restores kidney size when the cause is renal artery stenosis. Angioplasty is effective in patients with nonatherosclerotic renovascular diseases (non-ARVDs). Nevertheless, renal enlargement after angioplasty has not been fully examined. We conducted a retrospective study to examine this phenomenon in non-ARVD patients. Ten patients with a <100-mm pole-to-pole length of the poststenotic kidney were treated with angioplasty. Data were collected up to 12 months after angioplasty. The mean age was 28 years; the estimated glomerular filtration rate was 92 ± 7 mL/min/1.73 m² (mean ± SEM); blood pressure was 150/99 mmHg; 80% were women; and fibromuscular dysplasia was present in 90% of the patients. All patients had hypertension. The lengths of the poststenotic and contralateral kidney before angioplasty were 91 ± 1 and 111 ± 3 mm, respectively. After angioplasty, the length of the poststenotic kidney gradually increased during the 3 months after treatment (+5.4 mm) and that of the contralateral kidney decreased over the same time course (-3.7 mm). Enlargement was also found in the moderate atrophy subgroup (length < 92 mm), and it was greater in the <30 years old group. In a noteworthy case, renal size in the poststenotic kidney recovered from 87 to 102 mm after angioplasty. Our findings demonstrated that reduced renal size can be reversed after optimal angioplasty in non-ARVD patients, especially young patients, suggesting reversibility of the ischemic kidney.