Ultrasound diagnostics of renal artery stenosis: Stenosis criteria, CEUS and recurrent in-stent stenosis

Impact of Breathing Control Training Program on sonographic quantification of abdominal vasculature

OBJECTIVES

To compare vascular scanning parameters (vessel diameter, peak systolic velocity, end-diastolic velocity, and resistive index) and scanning time before and after breathing control training program for selected abdominal vessels.

METHODS

This study was pre and post quasi-experimental. The researchers designed a breathing training program that gives participants instructions through a video describing breathing maneuvers. Data were collected at the ultrasound laboratory/College of Health and Rehabilitation Sciences in Princess Nourah bint Abdul Rahman University, Riyadh, Saudi Arabia from January 2023 to November 2023. About 49 volunteers at the university participated in the study. Scanning was performed two times for the right renal artery, upper abdominal aorta, inferior vena cava, and superior mesenteric artery. Scanning time was measured before and after the program as well. A paired sample t-test was used to compare the parameters means and time before and after the program.

RESULTS

The program had a significant effect on the following parameters: right renal artery peak systolic velocity (p=0.042), upper abdominal aortic peak systolic velocity, and resistive index (p=0.014, p=0.014 respectively), superior mesenteric artery and inferior vena cava diameters (p=0.010 and p=0.020). The scanning time was reduced significantly (p<0.001).

CONCLUSION

The breathing training program saves time and improves ultrasound measurement quality. Hospitals and health centers should consider the importance of breathing control training programs before abdominal scanning.

Contrast-enhanced ultrasound evaluation of renal perfusion before angioplasty and its predictive value for hypertension

BACKGROUND

Atherosclerotic renal artery stenosis (ARAS) is a common disease in the elderly population.

OBJECTIVE

The aim was to develop a contrast-enhanced ultrasound (CEUS)-based model for predicting post-angioplasty improvement in hypertension in patients with severe ARAS.

METHODS

Thirty-five patients with severe ARAS (⩾ 70%) were included in this study, and 42 renal arteries received percutaneous transluminal renal arterial stenting. An optimal integral formula was developed from pre-interventional color-coded duplex sonography (CCDS) and CEUS parameters using least absolute shrinkage and selection operator (LASSO) regression and receiver operating characteristic (ROC) curve analysis. A model for predicting short-term hypertension improvement was established using the integral formula and clinical risk factors. Bootstrapping was used for internal validation.

RESULTS

Two integral formulas, LASSO.CCDS and LASSO.CEUS, were established. ROC curves of the two integral formulas showed that LASSO.CEUS was the better formula for predicting hypertension improvement (AUC 0.816, specificity 78.6%). Univariate and multivariate regression analyses showed that duration of hypertension (OR 0.841, P= 0.027), diabetes (OR = 0.019, P= 0.010), and LASSO.CEUS (OR 7.641, P= 0.052) were predictors of short-term hypertension improvement after interventional therapy. Using LASSO.CEUS combined with clinical risk factors, the following prediction model was established: logit (short-term improvement in hypertension) = 1.879-0.173 × hypertension duration - 3.961 × diabetes + 2.034 × LASSO.CEUS (AUC 0.939).

CONCLUSIONS

The model established using CEUS parameters and clinical risk factors could predict hypertension improvement after interventional therapy, but further research and verification are needed.

The performance of duplex ultrasonography for the assessment of renal artery stenosis in Takayasu's arteritis patients

BACKGROUND

This study intends to analyze the hemodynamic parameters of the renal artery in patients with Takayasu's arteritis (TAK) to explore the diagnostic efficacy of duplex ultrasonography in assessing the involved renal artery in TAK patients.

METHODS

One hundred fifteen TAK patients with 314 renal arteries were retrospectively analyzed, who were admitted to Peking Union Medical College Hospital between 2017 and 2022. These patients underwent both renal artery ultrasonography and angiography within a 4-week period. Specifically, the study compared seven ultrasonic parameters across groups categorized by the severity of renal artery stenosis (RAS), including noninvolvement, < 50% stenosis, 50-69% stenosis, and 70-99% stenosis. Receiver operating characteristic (ROC) curves were employed to determine the optimal threshold values for renal artery peak systolic velocity (RPSV), renal-aortic PSV ratio (RAR), and renal-interlobar PSV ratio (RIR) in order to diagnose various degrees of RAS in TAK patients.

RESULTS

Statistically significant differences were observed in RAR and RIR among the four groups (all P < 0.05). However, no statistically significant differences were found in RPSV and AT between the moderate stenosis group (50-69% stenosis) and the severe stenosis group (70-99% stenosis). The discrimination of interlobar PSV (IPSV) and interlobar RI (IRI) was not significant, and IEDV did not show statistical significance among the four groups. For TAK patients, the recommended thresholds of RPSV for the diagnosis of renal artery involvement (RAI), ≥ 50% RAS, and ≥ 70% RAS were determined to be 143 cm/s, 152 cm/s, and 183 cm/s, respectively. The sensitivities, specificities, and accuracies of these thresholds were all found to be greater than 80%. Additionally, the optimal thresholds of RIR for detecting RAI, ≥ 50% RAS, and ≥ 70% RAS were determined to be 4.6, 5.6, and 6.4, respectively, with satisfactory diagnostic efficiencies. The areas under the curve (AUCs) for RPSV and RIR were calculated to be 0.908 and 0.910, respectively, for the diagnosis of ≥ 50% RAS, and 0.876 and 0.882 for the diagnosis of ≥ 70% RAS. When the aortic PSV is greater than or equal to 140 cm/s, the RAR exhibits inadequate diagnostic efficacy. Conversely, when the aortic PSV is less than 140 cm/s, a RAR value of 2.2 or higher can be employed as the diagnostic threshold for identifying RAS of 70% or greater, with a sensitivity of 84.00%, specificity of 89.93%, and an overall accuracy of 89.08%.

CONCLUSION

In the present study, it has been demonstrated that RPSV and RIR possess substantial diagnostic value as ultrasonic parameters for diagnosing RAS in TAK patients. Furthermore, when assessing the diagnostic efficacy of RAR, it is crucial to consider the severity of aortic stenosis as a determining factor.

Abdominal Vascular Evaluation

The vascular lab (VL) is instrumental in diagnosing vascular diseases such as renal artery stenosis and mesenteric ischemia or following a patient after transjugular intrahepatic portal systemic shunt (TIPS) creation. This article discusses indications, protocol, and diagnostic criteria for abdominal vascular ultrasound. The vascular lab can be used to investigate pathology in the abdomen either as a preliminary screening tool to evaluate for a pathology such as mesenteric artery stenosis in a patient with food fear and weight loss, renal artery stenosis in a patient with refractory hypertension or renal failure, or as a diagnostic tool in follow up after a patient has undergone a transjugular intrahepatic portal systemic shunt (TIPS) for portal hypertension. The technical success of duplex ultrasonography of the abdomen can be compromised by respiratory motion, obesity, and intestinal gas. Therefore, duplex scanning is performed in the fasting state particularly in elective outpatient cases. In emergent cases when pathology such as acute mesenteric ischemia is suspected evaluation with CT angiography may be best.

Case Report: Endovascular Treatment of Chronic Atherosclerotic Renal Artery Total Occlusions with Failed Medical Therapy

Background

Current guidelines generally no longer support revascularization for chronic renal artery occlusive diseases because results from randomized controlled trials favor medical therapy over angioplasty. However, increasing reports indicate that patients with renal artery occlusion (RAO) can benefit from revascularization under certain circumstances.

Case summary

Here, we present a patient with renal artery stenosis (RAS) who does not have refractory hypertension or fit any clinical trial inclusion criteria by far. Medical therapy failed to prevent the progression of RAS in this patient, leading to total occlusion of his right renal artery. This patient had progressive renal insufficiency but recovered renal function after endovascular treatment.

Conclusion

This case demonstrates that angioplasty can be beneficial in selected RAO patients, especially those with residual renal function and collateral perfusion.

Gray-Scale, Color Doppler, Spectral Doppler, and Contrast-Enhanced Renal Artery Ultrasound: Imaging Techniques and Features

Renal artery stenosis (RAS) is increasingly being detected in elderly patients as life expectancy increases. RAS induces hypertension or reduces renal function. Computed tomography or magnetic resonance angiography are objective in detecting RAS but may cause iodine-induced nephrotoxicity or nephrogenic systemic fibrosis in patients with RAS. Ultrasound (US) is, by contrast, a noninvasive and real-time imaging modality useful in patients with reduced renal function. Renal US is not as sensitive for detecting RAS because this technique indirectly assesses the renal artery by analyzing intrarenal hemodynamic changes. Although, ideally, US would be used to directly evaluate the renal artery, its current utility for RAS detection remains unclear. The purpose of this review is to introduce how to assess renal artery with US, to describe imaging features of renal artery US, to compare renal artery US and renal US, and to show how to perform work-up in patients in whom RAS is suspected.

Value of contrast-enhanced ultrasound for diagnosis and follow-up of renal artery stenosis in patients with chronic kidney disease

OBJECTIVE

To evaluate whether contrast-enhanced ultrasound (CEUS) is an accurate, non-nephrotoxic diagnostic method and follow-up tool for use in patients with chronic kidney disease (CKD) and renal artery stenosis (RAS).

METHODS

In this prospective and monocentric study, we compared the sensitivity and specificity of CEUS for the diagnosis of RAS in CKD patients, using digital subtraction angiography (DSA) or computed tomographic angiography (CTA) as the gold standard methods. Further, the value of CEUS for distinguishing restenosis from other diseases was assessed. The ultrasound physicians conducted the examinations and served as the CEUS report readers who were blinded to the DSA or CTA results.

RESULTS

Patients with RAS (n = 60) were enrolled. Average patient age was 64.4 ± 18.0 years and median estimated glomerular filtration rate was 66.1 mL/min/1.73 m². CEUS was used to image 94 stenotic renal arteries and DSA- or CTA-verified stenosis was present in 96 renal arteries. The kappa value for CEUS was 0.776 (P < 0.001), with an accuracy of 92.5%, a sensitivity of 94.7%, and a specificity of 84.0%. The accuracy of CEUS was the same for the diagnosis of the CKD3b-5 group as for the CKD1-3a group (100% vs. 87.5%, P = 0.148). There was no difference in CEUS accuracy for the diagnosis of Takayasu RAS compared with atherosclerotic RAS (95.8% vs. 91.7%, P = 0.795). Twenty-nine CEUS examinations were performed to follow in-stent restenosis or progression of RAS, with a median follow-up time of 5.0 months (range 1.0-20.0). Two cases of in-stent restenosis in patients suffering from deteriorating kidney function and recurrent hypertension were examined by CEUS.

CONCLUSION

CEUS examination is a credible alternative for diagnosing moderate and severe RAS in patients with CKD, and is a reliable tool for follow-up surveillance after renal artery revascularization treatment. It shouldn't be thought as a color-coded duplex ultrasonography rescue in these patients.

Clinical and Renal Cortical Blood Perfusion Characteristics in Patients with Severe Atherosclerotic Renal Artery Stenosis Who Underwent Stent Implantation: A Single-center Retrospective Cohort Study

Objective This study aimed to observe the clinical imaging features of patients with severe atherosclerotic renal artery stenosis (ARAS) receiving stent implantation, and to evaluate the associations between baseline clinical and imaging factors and renal-function deterioration at a 1-year follow-up.Methods This study was a single-center retrospective cohort study. A total of 159 patients with unilateral severe ARAS who underwent stent implantation at Beijing Hospital between July 2017 and December 2020 were consecutively enrolled. According to the renal glomerular filtration rate (GFR), detected by radionuclide renal imaging at 1-year follow-up, all patients were divided into a poor-prognosis group (with a ≥30% decrease in renal GFR; n=32 cases) and a control group (127 cases). Clinical imaging data, including the renal cortical blood perfusion pre- and post-sent implantation, were analyzed. Univariate and multivariate logistic regression analysis was used to evaluate the associations between clinical and imaging factors and renal-function deterioration.Results Of the 159 patients enrolled, 83 (52.2%) were men, with an average age of (57.2±14.7) years. The patient age, rate of diabetes, and systolic blood and diastolic blood pressure in the poor-prognosis group were significantly higher than those in the control group (all P<0.05). Before stent treatment, patients in the poor-prognosis group, compared with the control group, had a significantly smaller area under the ascending curve (AUC1), area under the descending curve (AUC2), and peak intensity (PI), and a longer time to peak intensity (TTP) and mean transit time (MTT) (all P<0.05). After stent treatment, patients in the poor-prognosis group, compared with the control group, showed significantly smaller AUC1, AUC2, and PI, and longer MTT (all P<0.05). Multivariate logistic regression analysis indicated that age (OR=1.251, 95%CI: 1.113–1.406, P=0.0002), diabetes (OR=1.472, 95%CI: 1.110–1.952, P=0.007), systolic blood pressure (OR=1.339, 95%CI: 1.082–1.657, P=0.007), renal GFR (OR=2.025, 95%CI: 1.217–3.369, P=0.006), and AUC1 post-stent (OR=2.173, 95%CI: 1.148–4.113, P=0.017) were the factors associated with renal deterioration at the 1-year follow-up.Conclusions Patients with severe RAS with renal-function deterioration after stent implantation were older, and often had diabetes, hypertension, and impaired renal cortical perfusion. Age, diabetes, systolic blood pressure, renal GFR, and AUC1 after stent implantation were independent factors associated with short-term renal deterioration.

Difficulty and importance of diagnosing stenosis of renal branch artery in fibromuscular dysplasia: a case report

A 16-year-old patient presented with abdominal pain and sustained hypertension. Thorough evaluation including renography with and without captopril and renal vein renin sampling were normal. Duplex ultrasound, however, raised suspicion of a renal artery stenosis. This was confirmed by computed tomography angiography which showed a severe branch artery stenosis with post-stenotic dilatation consistent with focal fibromuscular dysplasia (FMD). As the hypertension was resistant to 3 classes of antihypertensive treatment, percutaneous transluminal renal angioplasty (PTRA) was offered. The procedure had immediate effect on the blood pressure. Without medication the patient remains normotensive 4 years after and the abdominal pain has only sporadically returned. The presented case illustrates the challenging process of diagnosing FMD-related renal branch artery stenosis as well as the potential benefits of PTRA in this patient group.

Sonographic 3-D Power Doppler Imaging Enhances Rapid Assessment of Morphologic and Pathologic Arteriovenous Fistula Variations

Early detection of pathologic variations in an arteriovenous fistula (AVF) is essential for preventing fistula dysfunction in individuals undergoing hemodialysis. This study aimed to evaluate the clinical applicability of 3-D tomographic ultrasound (tUS) for rapid and simple visualization of AVF morphology and pathology. We assessed 53 AVFs in 50 consecutive patients using 3-D tUS including secondary, blinded reading. For all examinations, a high-end ultrasound (US) device was used with linear probe, attached to a tUS system to allow freehand 3-D scanning. Participants were examined by 2-D US and 3-D tUS with different raw data (B-mode, power Doppler, B-flow). Additional angiography was available for 15 participants with scheduled interventions. In all participants, 3-D tUS allowed a 3-D representation of AVFs in angiographic-like images with good image quality. The 2-D US assessment took 7.9 ± 4.0 min. A 3-D power Doppler scan required, on average, 1.4 ± 0.6 min. Diagnostic accuracy of blinded reading for pathologies was high (86.8% for aneurysms and 79.2% for stenoses). Bland-Altman plots showed an excellent correlation of 3-D tUS with 2-D US and angiography. 3-D tUS is an easily and rapidly applicable method for visualizing morphologic and pathologic AVF variations. Color-coded 3-D reconstruction of power Doppler data simplifies detection of perfused aneurysms and stenoses.

Imaging strategies for safety surveillance after renal artery denervation

Renal denervation has emerged as a safe and effective therapy to lower blood pressure in hypertensive patients. In addition to the main renal arteries, branch vessels are also denervated in more contemporary studies. Accurate and reliable imaging in renal denervation patients is critical for long-term safety surveillance due to the small risk of renal artery stenosis that may occur after the procedure. This review summarizes three common non-invasive imaging modalities: Doppler ultrasound (DUS), computed tomography angiography (CTA), and magnetic resonance angiography (MRA). DUS is the most widely used owing to cost considerations, ease of use, and the fact that it is less invasive, avoids ionizing radiation exposure, and requires no contrast media use. Renal angiography is used to determine if renal artery stenosis is present when non-invasive imaging suggests renal artery stenosis. We compiled data from prior renal denervation studies as well as the more recent SPYRAL-HTN OFF MED Study and show that DUS demonstrates both high sensitivity and specificity for detecting renal stenosis de novo and in longitudinal assessment of renal artery patency after interventions. In the context of clinical trials DUS has been shown, together with the use of the baseline angiogram, to be effective in identifying stenosis in branch and accessory arteries and merits consideration as the main screening imaging modality to detect clinically significant renal artery stenosis after renal denervation and this is consistent with guidelines from the recent European Consensus Statement on Renal Denervation.

The Value of Contrast-Enhanced Ultrasound versus Doppler Ultrasound in Grading Renal Artery Stenosis

Objective

This study is aimed at exploring the accuracy of contrast-enhanced ultrasound (CEUS) in grading renal artery stenosis.

Methods

122 renal arteries with suspected renal artery stenosis were selected. DSA, DUS, and CEUS were performed for all patients with suspected renal artery stenosis in the research. DSA was selected as the gold standard. The sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) of CEUS or Doppler ultrasound (DUS) in the diagnosis of renal artery stenosis were analyzed. The consistency between CEUS and digital subtraction angiography (DSA) was compared. The accuracy of DUS or CEUS in grading renal artery stenosis was assessed by the area under the receiver operating characteristic (ROC) curves and compared between groups.

Results

The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of CEUS in the diagnosis of renal artery stenosis were 88.9%, 87.8%, 88.5%, 93.5%, and 80.0%, respectively. There was no significant difference in grading renal artery stenosis between CEUS and DSA (X² = 0.643, P = 0.424). 77 of the 122 renal arteries were diagnosed with the stenosis rate more than 30% by CEUS. Compared with the results of DSA, the kappa value of CEUS was 0.749 (P < 0.05).

Conclusion

CEUS is accurate in grading renal artery stenosis, and it may represent the method of choice in diagnosing renal artery stenosis.

Contrast-Enhanced Ultrasound Evaluation of Renal Blood Perfusion Changes After Percutaneous Transluminal Renal Angioplasty and Stenting for Severe Atherosclerotic Renal Artery Stenosis

This study used contrast-enhanced ultrasound (CEUS) to evaluate changes in renal cortical blood perfusion after percutaneous transluminal renal angioplasty and stenting (PTRAS) for severe renal artery stenosis (RAS) (≥70%). CEUS was performed in 21 patients with 24 severe RASs that underwent PTRAS. Renal cortical perfusion was quantitatively evaluated by comparing time intensity curve (TIC) parameters for SonoVue (Bracco, Milan, Italy) contrast enhancement, including peak intensity (PI), time to peak (TTP), mean transmit time (MTT), curve ascending slope (S), area under the curve (AUC), AUC-wash-in and AUC-wash-out. The parameters PI, TTP, MTT and S differed significantly between the pre-intervention and post-intervention TIC analysis (p < 0.05). Of the 24 pre-intervention curve appearances, 58.3% (14/24) improved after operation. The PI difference correlated positively with the estimated glomerular filtration rate difference (r = 0.433, p < 0.05). In conclusion, changes in some ultrasound perfusion parameters on CEUS and the shape of the TIC can be used to quantitatively and intuitively evaluate renal cortical blood perfusion change after PTRAS.

Ratio of diastolic to systolic blood pressure represents renal resistive index

Increased intrarenal vascular resistance is suggested to accompany chronic kidney diseases (CKD), which is known to be closely associated with hypertension. However, there are few studies that have examined the relationship between blood pressure and intrarenal vascular resistance. Renal color Doppler ultrasonography is one method that can non-invasively evaluate intrarenal vascular resistance. In this study, we comprehensively studied the correlations between ultrasonic parameters and blood pressure indices to elucidate their relationships. In total, 162 patients with suspected CKD were enrolled for this study. Demographics, blood pressure, blood test, urine test, and renal color Doppler ultrasonography data were obtained. The ratio of diastolic to systolic blood pressure (D/S ratio) and pulse pressure were calculated. Our results indicated strong negative correlations between the renal resistive index (RI) values in all four of the studied kidney regions and the D/S ratio. The RI values also showed significant correlations with diastolic pressure and pulse pressure, but they were weaker. Partial correlation coefficients between pulse pressure, mean arterial pressure, D/S ratio, and RI showed that D/S ratio significantly correlated with RI, but pulse pressure or mean arterial pressure did not. Systolic blood pressure did not correlate with any of the studied ultrasonic values. The negative correlation between RI values and the D/S ratio was still observed in subjects without renal dysfunction or any medications. In conclusion, D/S ratio, rather than pulse pressure or mean arterial pressure, would be the most appropriate index to estimate/calculate/judge intrarenal vascular resistance.

Renal Artery Stenosis in the Patient with Hypertension: Prevalence, Impact and Management

Atherosclerosis is the primary cause of renal artery stenosis. Atherosclerotic renal artery stenosis (ARAS) is associated with three clinical problems: renovascular hypertension, ischemic nephropathy and cardiac destabilization syndrome which pose huge healthcare implications. There is a significant rate of natural disease progression with worsening severity of renal artery stenosis when renal revascularization is not pursued in a timely manner. Selective sub-groups of individuals with ARAS have had good outcomes after percutaneous renal artery stenting (PTRAS). For example, individuals that underwent PTRAS and had improved renal function were reported to have a 45% survival advantage compared to those without improvement in their renal function. Advances in the imaging tools have allowed for better anatomic and physiologic measurements of ARAS. Measuring translesional hemodynamic gradients has allowed for accurate assessment of ARAS severity. Renal revascularization with PTRAS provides a survival advantage in individuals with significant hemodynamic renal artery stenosis lesions. It is important that we screen, diagnosis, intervene with invasive and medical treatments appropriately in these high-risk patients.

The role of computerized tomographic angiography in the diagnosis of pathologically modified renal arteries

Introduction: The most common causes of renal artery disease are stenosis, as a consequence of atherosclerosis and fibromuscular dysplasia. Computed tomographic (CT) angiography is a non-invasive method, which enables visualization of vascular structures and walls of blood vessels, as well as morphology of the renal parenchyma. Objective: To determine the importance of CT angiography in detecting the cause and degree of renal arterial disease. Methods: A total of 45 patients were included in the cross-sectional study conducted from March 2017 to March 2019 in the KBC DR Dragiša Mišović-Dedinje, Belgrade, Serbia. Criteria for inclusion were suspicion of secondary arterial hypertension, patients in preparation for kidney transplantation and in the follow-up period after transplantation, as well as patients with suspected traumatic lesions. We analyzed the causes of the disease, the morphology of the blood vessel wall, the percentage of stenosis, and the renal parenchyma. Results: The most common causes of renal arterial disease are atherosclerosis, which was found in 33 (73%) patients, renal artery aneurysm was found in 5 (11%) subjects, fibromuscular dysplasia in 4 (8.9%) and trauma in 1 (2) , 3%) of the patient. There were 10 (22.2%) patients with a significant (average 80 ± 14.5%) degree of stenosis. The sensitivity of CT angiography in the detection of atherosclerotic changes in the renal arteries was 87.9%, while the sensitivity of CT angiography in the detection of fibromuscular dysplasia was 75%. A statistically significant correlation was found between atherosclerotic stenosis of the renal arteries and a positive CTA finding (p = 0.0002). Conclusion: CT angiography is an important method of visualization and quantification of pathological changes in the renal arteries.

Follow-up of patients after revascularisation for peripheral arterial diseases: a consensus document from the European Society of Cardiology Working Group on Aorta and Peripheral Vascular Diseases and the European Society for Vascular Surgery

Peripheral arterial diseases comprise different clinical presentations, from cerebrovascular disease down to lower extremity artery disease, from subclinical to disabling symptoms and events. According to clinical presentation, the patient's general condition, anatomical location and extension of lesions, revascularisation may be needed in addition to best medical treatment. The 2017 European Society of Cardiology guidelines in collaboration with the European Society for Vascular Surgery have addressed the indications for revascularisation. While most cases are amenable to either endovascular or surgical revascularisation, maintaining long-term patency is often challenging. Early and late procedural complications, but also local and remote recurrences frequently lead to revascularisation failure. The rationale for surveillance is to propose the accurate implementation of preventive strategies to avoid other cardiovascular events and disease progression and avoid recurrence of symptoms and the need for redo revascularisation. Combined with vascular history and physical examination, duplex ultrasound scanning is the pivotal imaging technique for identifying revascularisation failures. Other non-invasive examinations (ankle and toe brachial index, computed tomography scan, magnetic resonance imaging) at regular intervals can optimise surveillance in specific settings. Currently, optimal revascularisation surveillance programmes are not well defined and systematic reviews addressing long-term results after revascularisation are lacking. We have systematically reviewed the literature addressing follow-up after revascularisation and we propose this consensus document as a complement to the recent guidelines for optimal surveillance of revascularised patients beyond the perioperative period.

Challenges in diagnosing and treating a patient with renal artery fibromuscular dysplasia: case report

Background

We present a patient with history of sinus venous thrombosis and hypertension during the last year. Her blood pressure was not controlled despite drugs, diet, and exercise. She denied symptoms. She does not smoke nor drink alcohol. Her body mass index was 20 kg/m², NYHA Class I/IV.

Case summary

A 40-year-old Latin-American female patient, concerned because despite taking verapamil 160 mg/day, losartan 100 mg/day, and hydrochlorothiazide 25 mg/day her diastolic blood pressure was over 100 mmHg. Routine serum and urine lab tests and a transthoracic echocardiogram were done and were normal. The treatment was increased over the next consultations but without control of her blood pressure. She developed resistant hypertension, and she was taking four antihypertensive drugs and two diuretics. A first renal artery Doppler was normal. Because of a high clinical suspicion a renal angio-CT was performed showing bilateral fibromuscular dysplasia. The patient underwent a renal artery angioplasty with balloon with excellent results and better control of her blood pressure after the procedure. Over the next month, her doctors were able to decrease her treatment to two drugs at intermediate doses. Currently, she is doing well and asymptomatic.

Discussion

Renal artery fibromuscular dysplasia (FMD) could be a challenging disease to be diagnosed. Patients with this condition may suffer from symptomatic and resistant hypertension. Many patients do not have abnormalities on their physical exam or in the routine lab tests. Treatment includes renal artery angioplasty if patient is symptomatic and blood pressure is resistant.

Rationale and study design for one-stop assessment of renal artery stenosis and renal microvascular perfusion with contrast-enhanced ultrasound for patients with suspected renovascular hypertension

BACKGROUND

Renal artery stenosis (RAS) is always associated with abnormalities in renal microvascular perfusion (RMP). However, few imaging methods can simultaneously evaluate the degree of luminal stenosis and RMP. Thus, this study will aim to evaluate the feasibility of using contrast-enhanced ultrasound (CEUS) for assessing both RAS and RMP to achieve a one-stop assessment of patients with suspected renovascular hypertension.

METHODS

This will be a single-center diagnostic study with a sample size of 440. Patients with chronic kidney disease (CKD) and suspected of having resistant hypertension will be eligible. Patients with Stages 1-3 CKD will undergo CEUS and computed tomography (CT) angiography (CTA). Values obtained by CEUS and CTA for diagnosing low-grade (lumen reduced by <60%) and high-grade (lumen reduced by ≥60%) RAS will be compared. Moreover, all patients will also undergo radionuclide imaging. The diagnostic value for RAS will be assessed by the receiver operating characteristic curve, including the accuracy, sensitivity, specificity, positive predictive values, negative predictive values, and area under the ROC. Pearson correlation analysis will be performed to assess the association between CEUS findings for RMP and glomerular filtration rate measured by a radionuclide imaging method.

CONCLUSION

The data gathered from this study will be used to evaluate the feasibility of expanding clinical applications of CEUS for evaluation of patients with suspected renovascular hypertension.

TRIAL REGISTRATION

Chinese Clinical Trial Registry, ChiCTR1800016252; https://www.chictr.org.cn.

Imaging studies in pediatric fibromuscular dysplasia (FMD): a single-center experience

BACKGROUND

Fibromuscular dysplasia (FMD) is a non-inflammatory vascular disease that in children unlike in adults shows no sex predilection. FMD is often underdiagnosed, and its pathophysiology is unclear. Delayed diagnosis may lead to refractory hypertension and decreases the chance of successful treatment. Doppler ultrasound (US), magnetic resonance angiography (MRA), computed tomography angiography (CTA), and catheter-based angiography (angiography) are currently used to help make a clinicoradiological diagnosis of FMD. The main aim of the study was to compare the efficacy of imaging modalities which can allow for earlier and improved detection. Furthermore, an anatomical mapping of the location of lesions can help determine the best treatment modalities.

METHODS

All patients with non-syndromic non-inflammatory renovascular hypertension were recruited from the Nephrology Department at the Children's Hospital of Philadelphia (CHOP) and enrolled in the U.S. FMD Registry maintained at the University of Michigan. Clinical presentation and imaging findings on US, CT, and MRI of children diagnosed with FMD were evaluated.

RESULTS

Mean age at diagnosis was 7 ± 4.9 years (4 months-17 years). Family history of hypertension (HTN) (52%), FMD (8.7%), Caucasian (60%), headache (48%), and HTN (80%) were the most prevalent symptom and sign at presentation. Bruits were 100% specific for renal artery stenosis (RAS) diagnosis but were heard in the minority of patients (3 patients, 12%). FMD was mainly unifocal within a single site (68%) or multiple sites (28%) and involved the main or first order renal branch in about 68% of children. Isolated distal lesions beyond the second order branches were found in about 25% of children. US imaging was significantly less sensitive than angiography (28%, p = 0.003). MRA had a better sensitivity (62.5%, p = 0.3) than US. Overall, CTA had the best sensitivity (84.2%, p = 0.4) compared to angiography; however, only angiography showed distal vessel disease.

CONCLUSIONS

Limitations of the study include the sample size and biases-only patients diagnosed with FMD were included in this study and most patients were referred to a pediatric nephrologist for unexplained hypertension. Angiography should be performed as part of the initial work-up of any child suspected of having renovascular FMD, regardless of the findings seen on US, MRA, or CTA.

Detection of transplant renal artery stenosis with contrast-enhanced ultrasound

Transplant renal artery stenosis (TRAS) is a vascular complication occurring during the first 2 years after kidney transplantation, with an incidence and a prevalence ranging from 1% to 23%, and from 1.5% to 4%, respectively. Detection of TRAS is the key, since most stenoses may progress to renal graft loss, however it may be difficult to detect due to its nonspecific clinical manifestations. Although Doppler ultrasound has become a primary imaging technique, digital subtraction angiography (DSA) remains the gold standard for diagnosing TRAS. We present a case of delayed graft function following kidney transplantation complicated by a lateral by-pass with prosthesis upstream and downstream of renal anastomosis, TRAS criteria were unclear using Doppler ultrasound, contrast-enhanced computed tomography-scan, and DSA. Only contrast-enhanced ultrasound (CE-US), observing a delayed and pulsating contest impregnation of renal parenchyma, supported the hypothesis of TRAS that was confirmed by the measurement of trans-anastomosis pressure gradient during DSA.

Clinical value of combining transvaginal contrast-enhanced ultrasonography with serum human epididymisprotein-4 and the resistance index for early-stage epithelial ovarian cancer

Objectives:

To increase accuracy of the detection and differential diagnosis of the early epithelial ovarian cancer (EOC) with transvaginal contrast-enhanced ultrasonography (TVCEUS) combining serum human epididymisprotein 4 (HE4), and resistance index (RI).

Methods:

This retrospectively case-control study of 230 patients with ovarian tumors were reviewed at the Department of Gynecology and Obstetrics, Zhongnan Hospital, Wuhan University, Wuhan, China between June 2008 and September 2015. Before the operation of 110 cases with EOC (Group A) and 120 cases of patients with benign ovarian tumor (Group B), we observe and calculate both Groups’ tumor vascular contrast-enhanced ultrasonography morphology scores (U), time-intensity curve (TIC) of contrast-enhanced ultrasonography, HE4, and RI. Results were compared with the histopathological analysis results.

Results:

The ultrasonography morphology scores, peak intensity (PI) enhancement rate (ER) with the parameters of the TIC and HE4 are higher in Group A compared with patients in Group B and the RI was lower than Group B. The detection rates for all indexes in the benign and malignant groups and their comparisons to the histopathological results were determined. The detection rate differences for HE4 (p=0.001), RI (p=0.001), U (p=0.001), PI (p=0.001), and ER (p=0.001) were all statistically significant (p<0.05).

Conclusion:

The high clinical value through combined TVCEUS, HE4, and RI detection can increase the sensitivity of the diagnosis and differential diagnosis of the early EOC.

Renal Ultrasound (and Doppler Sonography) in Hypertension: An Update

Ultrasound (US) allows the non-invasive evaluation of morphological changes of kidney structure (by means of B-Mode) and patterns of renal and extrarenal vascularization (by means of color-Doppler and contrast-enhanced US). In hypertensive subjects it offers a relevant contribution to the diagnosis of early renal damage, acute or chronic nephropathies and nephrovascular disease. However, morphological changes are often detected late and non-specific and in recent years evidence has increased regarding the clinical relevance of renal resistive index (RRI) for the study of vascular and renal parenchymal renal abnormalities. RRI is measured by Doppler sonography in an intrarenal artery, as the difference between the peak systolic and end-diastolic blood velocities divided by the peak systolic velocity. At first RRI was proved to be a marker of renal disease onset and progression; later the influence of systemic vascular properties on RRI was shown and authors claimed its use as an independent predictor of cardiovascular risk rather than of renal damage. Indeed, renal vascular resistance is only one of several renal (vascular compliance, interstitial and venous pressure), and extrarenal (heart rate, pulse pressure) determinants that concur to determine RRI individual values but not the most important one. The clinical relevance of RRI measurement as a surrogate endpoint of specific renal damage or/and as surrogate endpoint of atherosclerotic diffuse vascular damage is still debated.To summarize, from the literature: (a) In hypertensives with normal renal function and no albuminuria, especially in younger people, RRI is an early marker of renal damage that is especially useful when hypertension and diabetes concur in the same subjects. In these subjects RRI could improve current clinical scores used to stratify early renal damage. In older subjects RRI increases in accordance with the increase in systemic vascular stiffness and, because of this close relationship, RRI is also a marker of systemic atherosclerotic burden and the role of renal determinants can weaken. The clinical relevance was not specifically investigated. (b) In transplant kidney and in chronic renal disease high (>0.80) RRI values can independently predict renal failure. The recent claim that systemic (pulse pressure) rather than renal hemodynamic determinants sustain this predictive role of RRI, does not significantly reduce this predictive role of RRI. (c) Doppler ultrasound allows diagnosis and grading of renal stenosis in both fibromuscolar dysplastic and atherosclerotic diseases. Moreover, by RRI assay Doppler ultrasound can indirectly measure the hemodynamic impact of renal artery stenosis on the homolateral kidney, by virtue of the stenosis-related decrease in pulse pressure. However, in elderly subjects with atherosclerotic renal artery stenosis coexisting renal diseases can independently increase RRI by the augmentation in renal vascular stiffness and tubulo-interstitial pressure and hidden changes due to renal artery stenosis.