Renal Vein Renin Research Articles

A simple, refined approach to diagnosing renovascular hypertension in children: A 10-year study.

Despite advances in non-invasive vascular imaging, detection of renal artery stenosis via catheter angiography is the criterion standard for the diagnosis of renovascular hypertension (RVH). However, because of lack of evidence, the utility of various blood tests and imaging modalities remains unclear. We retrospectively analyzed the utility of blood tests (plasma renin activity [PRA], aldosterone, and renal vein renin[RVR] values) and imaging studies (computed tomography angiography [CTA], kidney ultrasonography[US]) by comparing them with catheter angiography. Ten pediatric patients with RVH at two institutions from January 2008 to December 2017 were recruited. The sensitivities for diagnosing RVH via imaging and blood tests (kidney [US], PRA, and aldosterone) were derived by examining patient records. Furthermore, the sensitivity and specificity of CT angiography were calculated by considering both the affected and non-affected renal arteries of the patients. A high sensitivity for diagnosing RVH via kidney US(89%) and PRA (80%) was observed. The sensitivity and specificity of CTA were 100%, each. RVR sampling did not aid in the diagnosis of RVH; only two of six patients with unilateral RVH showed significant laterality of RVR boundary ratios. Renal scintigraphy facilitated detection of a non-functional kidney (split renal function <5%). RVH in children could be diagnosed utilizing non-invasive blood and imaging tests, without catheter angiography. We recommend kidney length measurement along with measurement of PRA level, as a simple and highly useful screening test, followed by CTA as a diagnostic test.

Efficacy of percutaneous renal revascularization in resistant hypertension patients

Background: Renovascular hypertension is one of the most common potentially curable types of secondary hypertension. Medical therapy alone does not inhibit the progressive loss of renal function. The aim of the present study was to evaluate the efficacy of percutaneous renal revascularization in resistant hypertension patients. Methods: Forty-two patients aged ≥ 45 years with resistant hypertension having renal artery stenosis (>50% luminal narrowing assessed by quantitative renal angiography) undergoing percutaneous transluminal renal angioplasty (PTRA) were included in the study. The primary outcome measures were a response of blood pressure (BP) and the requirement of the number of hypertensive drugs, whereas the secondary outcome measure was to study the correlation of renal vein renin levels (RVRLs) with postrenal angioplasty BP response. Chi-square/Fisher's exact test and unpaired t-test were used to compare qualitative and quantitative variables, respectively. A paired t-test was used for intragroup comparison. Results: The mean systolic BP at 6-month follow-up (159.5 mmHg) was significantly less as compared to baseline (181.3 mmHg) (P = 0.0001). The mean diastolic BP at 6-month follow-up (94.4 mmHg) was significantly less as compared to baseline (106.5 mmHg) (P = 0.0001). The mean number of antihypertensive drugs used at the baseline and 6-month follow-up was 3.4 and 1.8, respectively, which was statistically significant (P = 0.001). There was no significant correlation of RVRL with postrenal angioplasty BP response. Conclusions: In patients with resistant hypertension, PTRA improved BP control and reduced the requirement of antihypertensive drugs.

Cure With Cryoablation of Arterial Hypertension Due to a Renin-Producing Tumor

We herein report on a 20 years old woman with stage I hypertension, who was found to carry a renin-producing tumor (RPT). Due to her young age, the patient underwent screening measurement of plasma renin and aldosterone, abdominal computed tomography (CT) angiography, and selective renal vein renin assessment to identify secondary hypertension. The patient was screened for secondary causes of hypertension and was diagnosed with secondary aldosteronism. Therefore, she underwent an abdominal computed tomography (CT) angiography that was reported as unremarkable. Selective renal vein renin studies showed overproduction of renin in the right kidney and a re-evaluation of her CT allowed detection of an 8-mm mass in her right kidney, suggesting the presence of a RPT. Considering the technical difficulty of renal sparing surgery a CT-guided cryoablation was undertaken, which provided long-term cure of arterial hypertension and normalization of plasma active renin concentration. RPTs usually present with a clinical phenotype featuring stage III and/or malignant hypertension and are held to be exceptionally rare. This case is unique in that it presented with stage I hypertension and a mild clinical phenotype. Moreover, to our knowledge this is the first case of RPTs shown to be safely treated with CT-guided cryoablation and found to be cured at long-term.

Reninoma: an uncommon cause of Renin-mediated hypertension.

Reninoma (juxtaglomerular cell tumor) is a rare cause of renin-mediated hypertension. Reninomas are usually diagnosed in adolescents and young adults with occasional reports in younger children. Patients typically present with a long history of headaches leading to a diagnosis of severe hypertension that responds well to antihypertensive treatment targeting the renin-angiotensin-aldosterone system. The clue to clinical diagnosis is the presence of hypokalemia and metabolic alkalosis on the first blood sample drawn before any treatment is instituted. Elevated blood levels of renin and aldosterone confirm the clinical suspicion of renin-mediated hypertension. Diagnostic imaging is employed to identify the source of excessive renin production. While renal ultrasound can miss reninoma, contrast CT or magnetic resonance imaging of the kidneys are diagnostic modalities of choice leading to the correct diagnosis. Renal vein renin sampling with lateralization might help to identify the site of excessive renin production. Nephron-sparing surgery is curative with maintenance of normal blood pressure after discontinuation of antihypertensive medications in the majority of patients. In this paper, we present the case of reninoma in an adolescent girl emphasizing clinical presentation, diagnostic evaluation, and medical and surgical treatment of this rare tumor. We also discuss important points in the management of children presenting with renin-mediated hypertension.

Mild Renal Artery Stenosis Can Induce Renovascular Hypertension and is Associated with Elevated Renal Vein Renin Secretion.

Renovascular hypertension is a syndrome which encompasses the physiological response of the kidney to changes in renal blood flow and renal perfusion pressure. Such physiological changes can occur with renal artery occlusion irrespective of the severity of the lesion. We have analyzed hypertensive patients with mild renal artery stenosis and compared them to patients with no stenosis. Renal vein renin sampling from catheterization of the renal vein was performed in all these patients. Patients with mild stenosis had higher renal vein renin ratio (3.01±1.5) than the patients with no stenosis (1.10± 0.29; p=0.002). Patients with mild stenosis were also found to have higher diastolic blood pressure and renal artery resistive indices when compared to patients with no stenosis. We therefore conclude that mild stenosis can precipitate renin-mediated hypertension in renovascular stenosis and also emphasis that parameters pertinent to renal physiology need to be evaluated before considering treatment options in patients with renal artery stenosis and medical management with RAAS blockade is the preferred modality of therapy for patients with renin-mediated hypertension.

Persistent Hypertension Despite Successful Dilation of a Stenotic Renal Artery in a Boy With Neurofibromatosis Type 1

Hypertension is one of the major complications in neurofibromatosis type 1 (NF1). It is known to be caused by renal artery stenosis or pheochromocytoma. However, more than half of hypertensive patients with NF1 do not have either disorder. We report here on a 13-year-old male with NF1 who had hypertension and a stenosis of the right renal artery associated with elevated renal vein renin on the diseased side. He underwent percutaneous transluminal renal angioplasty. In spite of successful dilation of the artery and normalized renin level, high blood pressure persisted beyond 6 months requiring antihypertensive medication. His wide pulse pressure suggested arterial stiffness due to NF1 vasculopathy. We posit that the cause of hypertension in this patient was considered to be arterial stiffness ascribed to NF1 vasculopathy rather than renal artery stenosis. Increased pulse pressure supports the hypothesis. This marker of arterial stiffness can be assessed non-invasively and should be evaluated routinely in NF1.

Educational Exhibit Abstract No. 422 - Diagnosis and treatment of renovascular hypertension in children

Learning Objectives To describe and illustrate with examples the techniques and unique management challenges in diagnosing and treating renovascular hypertension in children. Background Renovascular hypertension (RVH) is an uncommon yet important and potentially curable cause of secondary hypertension in children, accounting for approximately 10% of cases. The management of RVH in the pediatric population presents specific challenges related to both the size and expected growth of the involved vessels as well as the often bilateral, subsegmental, and intrarenal distribution of disease. A variety of laboratory and imaging criteria are useful in establishing a diagnosis of RVH, however catheter angiography augmented by direct renal vein renin measurement remains the test of choice. Likewise, percutaneous transluminal renal artery angioplasty remains a highly effective front line treatment option with the goal of reducing or eliminating the need for medical therapy and avoiding complex surgical revascularization. Clinical Findings/Procedure Details The clinical pathway for the diagnosis of RVH will be discussed including the relevant pre-procedural non-invasive imaging and laboratory tests aimed at excluding more common causes of secondary hypertension. The angiographic features of RVH will be illustrated in multiple cases, with an emphasis on findings unique to pediatric patients. The diagnostic relevance and proper technique for direct renal vein renin sampling will be described. Angiographic technique and equipment particularly useful for imaging and successful treatment of the pediatric population will be reviewed. Additional cases will illustrate the uncommon occurrence of angioplasty failure requiring stent placement as well as unexpected causes of hypertension encountered during angiography. Conclusion and/or Teaching Points Interventional radiologists play a pivotal role in the diagnosis and treatment renovascular hypertension in children. Knowledge of the unique features of this disease and technical challenges in the pediatric population is critical in providing potentially curative endovascular therapy.

Imaging in renovascular hypertension

Abstract Renovascular hypertension is the most common cause of secondary hypertension. Imaging plays an important role in establishing the diagnosis in these cases. Digital subtraction angiography (DSA) is the gold standard investigation in suspected cases. Colour Doppler Ultrasound (CDUS) is a very effective and cheap screening tool. CT angiography and MR angiography are effective and comparable alternatives to DSA. Captopril scintigraphy and renal vein renin sampling are used in selected patients in whom the functional significance of the renal artery stenosis is to be determined.

腎性高血圧症患者における分腎および下大(末梢)静脈血レニン活性

腎性高血圧症患者における分腎および下大(末梢)静脈血レニン活性

Taking a Family History of Hypertension: Is There Patient Care Benefit?

Taking a Family History of Hypertension: Is There Patient Care Benefit?

Physiological assessment of renal artery stenosis: Comparisons of resting with hyperemic renal pressure measurements

We compared resting and hyperemic pressure gradients induced by intrarenal papaverine for the assessment of renal artery stenosis (RAS). We also investigated the incidence of the QT interval prolongation and ventricular arrhythmias. In the coronary circulation, maximal hyperemia is essential in determining the significance of a stenosis. In the renal circulation, the role of maximal hyperemia for the assessment of RAS has not been established. In 55 patients with RAS (67 RAS), resting P(d)/P(a) ratio (the ratio between distal renal pressure to the aortic pressure), renal fractional flow reserve (FFR), and resting and hyperemic systolic gradients (RSG and HSG, respectively) were measured with a pressure guidewire. In a subset of 16 patients, renal vein renin activity (RVRA) was measured. HSG was significantly greater than RSG (20 ± 14 mm Hg vs. 9.0 ± 13 mm Hg, respectively; P < 0.001). Renal FFR was significantly lower than baseline P(d)/P(a) ratio (0.91 ± 0.06 vs. 0.94 ± 0.06 vs. respectively; P < 0.001). RVRA increased from 50 ± 66% at rest to 122 ± 112% at hyperemia, P < 0.01. At HSG of 21 mm Hg or renal FFR of 0.90, RVRA increased markedly (120%), but RVRA increased modestly (18%) when RSG was 16 mm Hg or resting P(d)/P(a) ratio was 0.93. The corrected QT intervals at baseline vs. hyperemia were not significantly different (433 ± 26 vs. 436 ± 25 msec, respectively; P = NS); no episodes of ventricular arrhythmias were noted. Renin production, an index of renal ischemia, was markedly greater at hyperemia than at rest, suggesting that RAS, with either an HSG of 21 mm Hg or a renal FFR of 0.90, can be considered a hemodynamically significant stenosis. Intrarenal papaverine neither prolonged the QT interval nor induced ventricular arrhythmias and the safety of which will need to be corroborated in a large study. © 2010 Wiley-Liss, Inc.

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.

Diagnosis of primary renal artery stenosis induced hypertension by detecting renal vein renin

1 病历摘要患儿,女,7岁,因血压升高3个月入院.患儿于3个月前突然出现头痛、呕吐,立即到当地医院就诊,测血压为200/160 mm Hg(1 mm Hg=0.133 kPa),头颅CT示:颅内出血(脑干血肿).予静脉滴注硝普钠,血压控制不理想(160/110 mm Hg左右).无尿频、尿急、尿痛,无少尿及血尿史,无发作性软瘫,无高血压家族史.既往有反复扁桃体炎病史.双肾螺旋CT血管造影联合三维血管重建:左肾动脉上级分支起始段明显狭窄,左肾动脉狭窄.当地医院诊断为肾动脉狭窄性高血压,予左肾动脉结扎术,术后未服降压药物血压可维持在110/85 mm Hg左右,术后第5天无明显诱因血压再次升高,可达160/110 mm Hg,加服硝苯地平控释片、倍他洛克(酒石酸美托洛尔)后,将血压维持在120/95 mm Hg左右,为进一步明确高血压病因来我院就诊。

Treatment of renovascular hypertension by transluminal angioplasty – 13 years experience in a single centre

Objective. The study is a follow‐up on treatment of renovascular hypertension (RVH) with percutaneous transluminal renal angioplasty (PTRA). Methods. Patients were screened on the basis of clinical criteria of increased probability of RVH with renography and in selected cases with renal vein renin measurements. A positive work‐up suggesting a functionally important renal artery stenosis led to renal angiography and PTRA if stenosis was confirmed; in 59%, an intravascular stent was inserted. Results. Outcome of treatment was classified as follows – group I: normotensive without medication; group II: with improved control of blood pressure; group III: unchanged blood pressure control. Grouping was performed immediately after treatment, at 1 month, 6 months and at the latest follow‐up. One hundred‐and‐twenty‐two patients (124 atherosclerotic and 12 fibromuscular lesions) were treated during 13 years. Immediately after PTRA the patients were grouped as follows – I: 31%, II: 59%, III: 10%. At 1 month, I: 13%, II: 72%, III: 15%; at 6 months, I: 11%, II: 74%, III: 15%, and at the latest follow‐up, I: 11%, II: 78%, III: 11%. There were few significant complications, and renal function remained on average stable. Conclusion. PTRA is an effective treatment of RVH in patients selected by signs of a flow‐restricting stenosis. Twelve percent were normotensive after angioplasty and a further 77% had better controlled hypertension. Few complications were seen and renal function was on average unchanged as measured by serum creatinine.

Is Renal Artery Stenting the Correct Treatmentof Renal Artery Stenosis?

The case favoring renal artery stenting for individuals with renal artery hypertension is largely circumstantial. At best, the clinical evidence presented in this discussion is derived primarily from nonrandomized cohort studies. It would certainly be easier to argue that medical therapy is preferred for such individuals because there are 3 published randomized clinical trials that concluded just that and none that support renal artery intervention. Nonetheless, there is considerable evidence to support the role for revascularization in general, and stenting specifically, as an important adjunctive therapy to medical therapy in the care of patients with renal artery stenosis (RAS). The argument has 3 principal components: observations about the impact on cardiovascular physiology, end-organ effects, and natural history. Response by Dworkin and Jamerson p 270 RAS is associated with and is an important cause of secondary hypertension. RAS causes endocrine activation with release of renin from renal juxtaglomerular cells. Renin catalyzes the breakdown of angiotensinogen to angiotensin I. Angiotensin I is transformed by angiotensin-converting enzyme into angiotensin II, and angiotensin II promotes the release of aldosterone from the adrenal cortex.1 Angiotensin II is a potent vasoconstrictor,2 substantially more potent than epinephrine, and is implicated in end-organ damage in the heart3 and kidney.4 RAS is suggested to cause 2 types of hypertension. With unilateral RAS and a normally perfused and normally functioning contralateral kidney, blood pressure elevation is referred to as “renin dependent” and is characterized by increased peripheral resistance.5,6 In this circumstance, renin and angiotensin levels remain elevated, but volume expansion is limited by natriuresis of the contralateral normally functioning kidney.6 Importantly, although renin levels are elevated, the value of peripheral or even renal vein renin values is limited by substantial overlap with patients having essential hypertension.7,8 When stenoses are bilateral or when the …

Adverse outcomes of renovascular hypertension during pregnancy

A 26-year-old primigravida, with no history of hypertension, presented at 20 weeks of gestation with severe pre-eclampsia. A pelvic ultrasound revealed intrauterine fetal death, probably caused by placental abruption. The pregnancy was terminated by induction with oxytocin, followed by a vaginal breech delivery. The patient remained hypertensive for 8 weeks after delivery. Physical examination, laboratory investigation, renal angiogram and renal-vein renin sampling. An atrophic right kidney secondary to an occluded right renal artery, probably caused by dissected fibromuscular dysplasia; a contralateral high-grade stenosis secondary to fibromuscular dysplasia. Right nephrectomy and angioplasty of the left renal artery.

Hypertension with renal carcinoma. An effect of arterial embolization.

A patient presented with mediastinal metastases from renal adenocarcinoma. Palliative therapy included Gelfoam and steel coil embolization of the right renal artery. Six weeks later he was found to have developed severe hypertension. Arteriogram revealed collateral vessels which supplied the tumor; the renal vein renin activity was four times higher on the right than on the left. We suspect that infarction of the kidney was not complete because of collateral arterial supply, and renin-dependent hypertension was the result. Thus, it may be hazardous to embolize large hypernephromas without subsequent nephrectomy.

Catheter-Based Therapy for Atherosclerotic Renal Artery Stenosis

Atherosclerotic renal artery stenosis (RAS) is more common than has been previously appreciated1,2 and is an independent predictor of death regardless of the presence, severity, or method of revascularization of coronary artery disease.3–5 Among 1235 patients undergoing diagnostic coronary angiography, multivariate analysis demonstrated that RAS (>50%) was a stronger independent predictor of all-cause mortality (relative risk [RR], 2.9; 95% confidence interval [CI], 1.7 to 7.0) than congestive heart failure (RR, 2.3; 95% CI, 1.3 to 4.1), elevated left ventricular ejection fraction (RR, 1.7; 95% CI, 1.2 to 2.2), or decreased renal function (serum creatinine) (RR, 1.3; 95% CI, 1.1 to 1.5).3 A subsequent expansion of that study group, extended to 3987 patients undergoing abdominal aortography at the time of diagnostic cardiac catheterization, identified an incremental effect of the severity of RAS on the 4-year mortality rates. They found that a mild-to-moderate (50%) RAS was associated with a 30% 4-year mortality rate, which almost doubled (52%) with severe (>95%) RAS.4 The cause-and-effect relation between RAS and death is uncertain. It is possible that the presence of RAS is simply a marker for more diffuse or extensive atherosclerosis, which would result in more vascular-related deaths. However, there is one study5 that raises the possibility that the treatment of RAS with a renal stent in patients with renal insufficiency can improve mortality rates. In this trial, patients who improved their renal function after renal stent placement had significantly better survival rates compared with those whose renal function did not improve. A dedicated educational effort aimed at improving the diagnosis and treatment of peripheral arterial disease, including RAS, has been supported over the past 10 years by several professional societies.6–8 There is now objective evidence from the Medicare database that this effort to increase the number of patients …

Interventional radiology for renovascular hypertension in children

Pediatric renovascular hypertension is an uncommon but important clinical problem. Atherosclerosis is rare in children, who typically suffer from fibromuscular dysplasia, neurofibromatosis type 1, Williams syndrome, or certain other rare conditions. Children with renovascular disease often have involvement of other arteries including the aorta and mesenteric and cerebral vessels. The pediatric interventional radiology service has a vital role in the diagnosis, evaluation, and treatment of renovascular hypertension. Renal vein renin sampling appears to be more useful in children than in adults, because their arterial disease is more often bilateral and segmental. Diagnostic angiography is still superior to less-invasive methods of imaging the renal arteries, especially the smaller branches. Interventional options include angioplasty, stenting, and ethanol ablation. Angioplasty is almost always technically successful and usually gives a worthwhile clinical improvement. Stenting is only used in children when angioplasty fails. Ethanol embolization may be appropriate in children with focal renin-producing areas that are untreatable by angioplasty.

The usefulness of renal vein renin studies in hypertensive children: a 25-year experience.

Lateralised renin secretion predicts improvement following surgery/angioplasty of the affected kidney in paediatric hypertension. We retrospectively analysed all our renal vein renin (RVR) studies undertaken in hypertensive children and their subsequent clinical outcomes over a 25-year period. The outcomes were categorised as cure, improvement or no change in hypertension. The proportions that benefited by 'following' or 'ignoring' the RVR results in relation to the aetiology of hypertension and subsequent therapy were compared. A ratio between the RVR value of the dominant kidney and that of the contralateral kidney (R/Rc ratio) above 1.5 was considered to show significant lateralisation. A ratio between RVR value of the contralateral kidney and that of the caudal inferior vena cava (Rc/P ratio) of less than 1.3 was considered to indicate contralateral renin suppression. Of 233 RVR records, 137 were suitable for analysis. Of these, 39 had reflux nephropathy (RN), 73 renovascular disease (RVD) and the others miscellaneous conditions. Of the 39 hypertensive children with RN, the R/Rc ratio was over 1.5 in 20 subjects, of whom 11 underwent surgery. Amongst the 19 with an R/Rc less than 1.5, 4 also had surgery. Of the 73 hypertensive children with RVD, the R/Rc ratio was over 1.5 in 38 subjects, of whom 20 underwent surgery/angioplasty. Amongst the 35 with an R/Rc less than 1.5, 7 also underwent surgery/angioplasty. In RN there was no significant difference in the proportion that improved with allocated treatment, as suggested by the 'test' when compared with those who were 'misallocated'. In RVD, however, the proportion improved (35.0%) by 'following the test' (i.e. R/Rc ratio) was significantly greater than the proportion improved (12.5%) in the group in whom the test was 'ignored'. This was true for both R/Rc and Rc/P ratios. Thus, RVR measurements are useful for identifying hypertensive children with RVD that may have a favourable outcome after surgery, but this does not apply to children with RN. Measurements, however, may have diagnostic value even if surgery or angioplasty is not anticipated.