Renal sympathetic denervation for resistant hypertension: where do we stand after more than a decade / Denervação simpática renal para hipertensão resistente: situação depois de mais de uma década

Abstract Despite the current availability of safe and efficient drugs for treating hypertension, a substantial number of patients are drug-resistant hypertensives. Aiming this condition, a relatively new approach named catheter-based renal denervation was developed. We have now a clinically relevant time window to review the efficacy of renal denervation for treating this form of hypertension. This short review addresses the physiological contribution of renal sympathetic nerves for blood pressure control and discusses the pros and cons of renal denervation procedure for the treatment of resistant hypertension.

Resumo Em que pese a atual disponibilidade de medicamentos seguros e eficientes para o tratamento da hipertensão, um número significativo de pacientes sofre de hipertensão arterial resistente a tratamento medicamentoso. Em vista dessa condição, foi desenvolvida uma abordagem relativamente nova, denominada denervação renal por cateter. Dispomos atualmente de uma janela de tempo clinicamente relevante para analisar a eficácia da denervação renal no tratamento dessa modalidade de hipertensão. A presente revisão aborda a contribuição fisiológica dos nervos renais simpáticos no controle da pressão arterial e discute os prós e contras do procedimento de denervação renal no tratamento da hipertensão resistente.

Extra-adrenal Pheochromocytoma Associated With Segmental Renal Artery Compression and Pseudostenosis.

Classically, pheochromocytomas and paragangliomas result in hypertension secondary to an excess release of catecholamines. However, when the tumor arises near the renal hilum, hypertension may also be secondary to renal artery stenosis, which can occur via several purported mechanisms. We describe an unusual case of a hereditary, extra-adrenal pheochromocytoma causing right lower pole renal artery pseudostenosis, pertinent radiologic signs, relevant surgical findings, and subsequent resolution after extirpative surgery.

Revisiting renovascular imaging for renal sympathetic denervation: current techniques and applications.

UNLABELLED: Renal sympathetic denervation (RDN) is an emerging technique in the treatment of resistant hypertension, most commonly performed using an endovascular approach. Clinical and anatomical criteria for RDN are well established and imaging plays an integral role in selecting patients with suitable anatomy, procedural planning and device selection. Nevertheless, the current body of literature surrounding imaging related to RDN remains limited. The purpose of this article is to illustrate the expectations and limitations of various imaging techniques, including Doppler ultrasound, CT angiography, MR angiography and newer techniques such as non-contrast MR angiography, in the context of RDN. KEY POINTS: • To understand the role of imaging in renal denervation • To understand strengths and weaknesses of current imaging techniques • To understand the relevant imaging findings in the context of renal denervation.

[Diagnosis and treatment of patients with secondary arterial hypertension of adrenal and renal genesis].

A multidisciplinary approach to the diagnosis and treatment of patients with symptomatic arterial hypertension enabled us to identify 154 patients with adrenal tumors. These patients underwent adrenalectomy for following reasons: pheochromocytoma--73 patients, aldosteronoma-- 43 patients, corticosteroma--22 patients, incidentalomas--16 patients. After surgery, stable normalization of blood pressure (BP) occurred in 84.4% of cases. Requirement of antihypertensive therapy was preserved in 15.6% cases, but blood pressure did not reach the preoperative levels in any of the treated patients. Among 81 patients with renal hypertension, 67 patients underwent balloon angioplasty with stent implantation. Cause of narrowing of renal artery was atherosclerotic lesion in 48 (71.6%) patients, fibromuscular dysplasia--in 18 (26.8 %) patients, and Takayasu's disease--in 12 year-old girl. In the immediate postoperative period, normalization of blood pressure was occurred in all patients who underwent surgery for renovascular hypertension.

Renal sympathetic denervation for the treatment of refractory hypertension.

Resistant hypertension poses significant health concerns. There are strong demands for new and safe therapies to control resistant hypertension while addressing its common causes, specifically poor compliance to lifelong polypharmacy, lifestyle modifications, and physician inertia. The sympathetic nervous system plays a significant pathophysiological role in hypertension. Surgical sympathectomy for blood pressure reduction is an old but extremely efficacious therapeutic concept, now abandoned with the dawn of a safer contemporary pharmacology era. Recently, clinical studies have revealed promising results for safe and sustained blood pressure reduction with percutaneous renal sympathetic denervation. This is a novel, minimally invasive, device-based therapy, specifically targeting and ablating the renal artery nerves with radiofrequency waves without permanent implantation. There are also reported additional benefits in related comorbidities, such as impaired glucose metabolism, renal impairment, left ventricular hypertrophy, heart failure, and others. This review focuses on how selective renal sympathetic denervation works, its present and potential therapeutic indications, and its future directions.

Almanac 2013: novel non-coronary cardiac interventions.

Recent innovations in interventional cardiology have dramatically expanded the therapeutic options for patients with cardiac conditions. Interventional cardiology is no longer limited to the treatment of coronary artery disease but allows also treatment of valvular disease, stroke prevention, hypertension, etc. One of the most important new treatment options is the percutaneous treatment for aortic valve stenosis (transcatheter aortic valve implantation), since aortic valve disease is a rather common problem in elderly patients, with many of them at high risk for surgery. Similarly, mitral regurgitation is often associated with comorbidities which make surgery high risk. The MitraClip is a promising percutaneous alternative to surgical valve repair or replacement. Other procedures discussed in this review are the percutaneous left atrial appendage closure as a non-pharmacologic therapy to prevent strokes, and renal denervation for resistant hypertension. This review explains the basic principles of these procedures, the most important clinical evidence, and also provides additional recent clinical data on each of these them.

[Renal denervation. Current developments]. / Renale Denervation. Aktuelle Entwicklungen.

UNLABELLED: METHODICAL INNOVATION: Renal denervation is a catheter-based, endovascular procedure for the treatment of drug-resistant hypertension. The aim of the therapy is to lower the blood pressure < 140/90 mmHg. PERFORMANCE: Even after successful minimally invasive therapy patients usually continue to take three or more antihypertensive drugs. Currently there is no evidence that renal denervation is a good option for the treatment of well-controlled hypertension in order to dispense with antihypertensive drugs. In carefully selected patients the mean reduction in systolic and diastolic blood pressure after renal denervation is 25-30 mmHg and 10-15 mmHg, respectively. ACHIEVEMENTS: Procedure-related or device-related complications are rare. Ablation catheters from different manufactures differ greatly in handling properties; however, up to now there is no evidence for relevant differences in safety and efficacy between the devices available.

Native nephrectomy in pediatric transplantation--less is more!

OBJECTIVE: Indications for pre-transplantation native nephrectomy (PTNN) include chronic renal parenchymal infection, proteinuria, intractable hypertension, polycystic kidneys and malignancy. Our aim was to establish the frequency and reasons for PTNN in children undergoing renal transplant at our center. MATERIALS AND METHODS: Children listed for renal transplant between 1998 and 2010 who underwent PTNN were analyzed. Etiology of established renal failure, indication for nephrectomy, stage of chronic kidney disease, laterality, complications, and timing of subsequent transplant were determined. Outcome of children, and that of preserved native kidneys following transplant, was reviewed. RESULTS: 21/203 children listed for transplant (10.3%) underwent PTNN (32 nephrectomies). Indications were drug-resistant proteinuria (6 children), recurrent upper tract urosepsis (6), refractory hypertension (4), malignancy/malignant predisposition (4), concomitant procedure during ureterocystoplasty (1). Median age at nephrectomy was 3.3 years; 86% had impaired renal function at time of (first) nephrectomy. Median time until transplantation following bilateral nephrectomy was 1.7 years. 19/21 children have been transplanted; 17 reached stable graft function. Only 2 children who did not undergo PTNN required nephrectomy post-transplant. CONCLUSION: When malignancies were excluded, PTNN was performed in a minority (8.4%) of children, mainly for proteinuria. This adds great advantage by reducing morbidity. Resulting graft function seems favorable.

Time course of hydronephrotic changes following unilateral pyeloplasty.

OBJECTIVES: The temporal pattern of hydronephrotic change following pyeloplasty has not been well defined. To address this issue, 23 years of postpyeloplasty follow-up data from a single surgeon were analyzed. PATIENTS AND METHODS: Records of dismembered pyeloplasty from 1986 to 2004 were retrospectively reviewed. Ultrasound follow-ups were conducted at 3-6-month intervals after surgery for up to 3 years, and were then extended to either annually or biannually until the completion of puberty. Overall outcome of hydronephrosis (HN), timing of initial improvement and normalization were determined. Factors associated with these changes were examined. RESULTS: Of 215 patients who completed follow-up of at least 5 years, about 80% experienced either normalization or improvement. Once they had shown improvement of HN during follow-up, no recurrence was observed. The median time for recognition of initial improvement and normalization of HN was 8 months and 41 months after surgery, respectively. Multivariate analysis revealed that the presence of immediate postoperative obstruction was a negative factor for initial improvement. Symptomatic presentation and no initial improvement until 6 months after pyeloplasty turned out to be negative factors for normalization. CONCLUSIONS: The results confirm the excellent long-term outcome of pyeloplasty, and highlight the importance of frequent ultrasound until initial improvement of HN, when subsequent ultrasound follow-ups may be safely omitted to focus on follow-up of renal function, proteinuria and hypertension.

Laparoscopic and robotic partial nephrectomy without renal ischaemia for tumours larger than 4 cm: perioperative and functional outcomes.

PURPOSE: To evaluate the technical feasibility, safety and functional outcomes of zero ischaemia laparoscopic and robotic partial nephrectomy with controlled hypotension for renal tumours larger than 4 cm. METHODS: We evaluated 121 consecutive patients with American Society of Anaesthesiologists (ASA) scores 1-2 who underwent laparoscopic (n = 70) or robotic (n = 51) partial nephrectomy with controlled hypotension with either tumour size ≤4 cm (group 1, n = 78) or tumour size >4 cm (group 2, n = 43) performed by a single surgeon from December 2010 to December 2011. Operative data, complications, serum creatinine, estimated glomerular filtration rates and effective renal plasma flow calculated from 99mTc-mercaptoacetyltriglycine renal scintigraphy were compared. Differences between groups were evaluated by the Chi-square test and the Student's t test. RESULTS: A significant difference in mean intraoperative blood loss and postoperative complications was found between the two groups: 168 ml (range: 10-600 ml in group 1) and 205 ml (range: 90-700 ml in group 2); p = 0.005, and 6.4 % versus 18.6 %; p = 0.004, respectively. The mean percentage decrease of ERPF of the operated kidney was 1.8 % in group 1 and 4.1 % in group 2. CONCLUSIONS: Laparoscopic and robotic partial nephrectomy with controlled hypotension for tumours >4 cm in ASA 1-2 patients was feasible with significant higher intraoperative blood loss and postoperative complications compared to smaller renal masses. The benefits of avoiding hilar clamping to preserve kidney function seem excellent.

Hybrid laparoscopic technique for renal artery Takayasu arteritis.

OBJECTIVE: To evaluate the feasibility of combined laparoscopic technique for different types of vascular reconstruction in the treatment of Takayasu renal artery stenosis. DESIGN: Retrospective study of seven cases of renal artery stenosis caused by Takayasu arteritis (TA). MATERIALS: Institutional practice and hospitalised patients. All these patients manifested renal arterial hypertension and failed to percutaneous transluminal angioplasty (PTA) treatment. Different types of revascularisation using hybrid laparoscopic technique were applied. METHODS: Laparoscopic renal artery isolation and kidney mobilisation were first performed. Several types of vascular reconstruction were performed as two patients underwent autotransplantation, four patients aortorenal bypass and one splenorenal bypass. For bypass patients, hypogastric artery was harvested by laparoscopic approach while saphenous vein and spleen artery were dissected by conventional opening. Autotransplantation and arterial anastomosis were then performed through an open incision. RESULTS: All procedures were performed successfully without major intraoperative complications. The total operative time was 191 (130-280) min while laparoscopic part was 62 (40-105) min. The mean blood loss was 261 (150-400) ml. Postoperative blood pressure returned to normal in five patients but two others required single-agent antihypertensive medication. Minor complications included lumbar artery injury and flank pain each in one case. The anastomosis was patent in all patients and no re-stenosis occurred during 6-40 months of follow-up. CONCLUSIONS: Hybrid laparoscopic techniques involving renal artery dissection and hypogastric artery harvesting are feasible in surgical treatment of Takayasu renal arteritis. This hybrid surgical technique provides an alternative approach to revascularise the renal circulation, especially for the patients of PTA treatment failure.

[Ascending aorta-abdominal aorta bypass for a patient with renal hypertension induced by aortitis syndrome; report of a case].

A 58-year-old woman was admitted to our institute. Aortitis syndrome was diagnosed when she was 39 years old. She developed intractable hypertension several years prior, and a computed tomography (CT) scan showed severe calcified stenosis of the descending aorta. The ankle brachial pressure index of the right leg was 0.70 and that of the left leg was 0.63. Plasma renin activity was 4.8 ng/ml/h. Ascending aorta-abdominal aorta bypass grafting was scheduled. The operation was successfully performed under partial cardiopulmonary bypass to control arterial blood pressure. An implanted graft was 14 mm in diameter. The postoperative ankle brachial pressure index of the right leg was 1.07 and that of the left leg was 1.03. Postoperative plasma renin activity was 0.2 ng/ml/h, and three-dimensional CT revealed that the implanted graft was patent. Postoperatively, hypertension was well controlled without medication.

Nephrectomy for hypertension in pediatric patients with a unilateral poorly functioning kidney: a contemporary cohort.

PURPOSE: A unilateral poorly or non-functioning kidney is a cause of hypertension in children. We report the outcomes of pediatric patients with unilateral renal parenchymal disease who underwent nephrectomy for hypertension. MATERIALS AND METHODS: Consecutive hypertensive children undergoing nephrectomy with a unilateral poorly or non-functioning kidney were retrospectively reviewed; preoperative and postoperative clinical variables were analyzed. RESULTS: From July 2002 to August 2009, 21 patients (8M:13F) with average age 3.5 years and average follow-up 17.8 months were studied. Eleven patients had multicystic dysplastic kidney, 8 had reflux nephropathy, and 2 had ureteropelvic junction obstruction. Fourteen of 21 (67%) had blood pressure normalization after nephrectomy. Seven of 11 with MCDK were normotensive postoperatively compared to 6/8 patients with reflux nephropathy, and 1/2 patients with UPJ obstruction. Of the 14 patients normotensive postoperatively, 7 were on antihypertensives prior to surgery. Four of 7 patients stopped their anti-hypertensive medications postoperatively, 2 decreased from 3 and 4 medications to 1, and 1 remained on an ACE inhibitor. There were 2 patients with contralateral renal scarring, both of which remained hypertensive postoperatively. CONCLUSIONS: Nephrectomy in hypertensive pediatric patients with a unilateral poorly functioning or non-functioning kidney yielded hypertension resolution in 67% (14/21), permitting cessation or diminution of antihypertensives in many patients. Given the alternative of lifelong antihypertensives with the risk of medication non-compliance and side-effects, nephrectomy is a logical option of care which can be offered to patients and families with informed knowledge of the potential for cure.

Renal autotransplantation for the treatment of renovascular hypertension in the pediatric population.

PURPOSE: To evaluate the effectiveness of renal autotransplantation (RA) for the treatment of renovascular hypertension (RVH) in a selected group of children in whom medical care, a percutaneous transluminal angioplasty or vascular reconstruction failed or was technically impossible, in addition to the short-term and long-term morbidity. MATERIALS AND METHODS: A retrospective case review of 13 pediatric patients with severe or complicated RVH who underwent RA between May 1993 and August 2008 was conducted. We defined blood pressure (BP) response as follows: Cured: normal BP values with no need of antihypertensive medication (AM); Improved: normal BP values with AM requirements; Failed: abnormal BP values despite treatment with AM. RESULTS: 16 RA were performed in 7 female and 6 male patients. Bilateral RA were performed in 2 females and in 1 male. The average age at consultation for hypertension was 8.5 years (range 4-12 years) and the time of transplantation was 9.12 years (range 6-13 years). Etiological diagnoses were: Takayasu disease (n = 5); renal artery fibrodysplasia (n = 3); mid-aortic syndrome (n = 3) and neurofibromatosis type I (n = 2). Results after RA were: Cured: 61.5%; Improved: 38.5%. No patient presented therapeutic failure during follow up time (median = 53.4 months). Only 1 case presented a postoperative complication. CONCLUSIONS: RA is a procedure with no mortality and low morbidity rates that renders very satisfactory therapeutic results in the pediatric population.

[Ureteropelvic junction obstruction with renal hypertension]. / Renaler Hypertonus bei Ureterabgangsenge.

Renal hypertension can occur with unilateral ureteropelvic junction obstruction and consecutive hydronephrosis. It is rarely the main symptom, normally in adults flank pain is in the foreground. We report a case of renal hypertension with ureteropelvic junction obstruction successfully corrected by laparoscopic pyeloplasty and discuss the pathophysiology.

Role of laparoscopic nephrectomy for refractory hypertension in poorly functioning kidneys.

INTRODUCTION: Hypertension is a common medical problem mainly treated by effective antihypertensive drugs. Persistent hypertension can be difficult to manage and have detrimental effect on vital organs. Nephrectomy of poorly functioning kidneys may be indicated in a minority of such cases. PATIENTS AND METHODS: We performed laparoscopic nephrectomy on 12 patients with refractory hypertension. RESULTS: Eight had complete response, three had partial response and one had no response. CONCLUSIONS: Laparoscopic nephrectomy has a role in carefully selected adult patients with refractory hypertension due to non-functioning kidney. Patients need to understand the surgical risks as well as the small risk of failure to treat hypertension.

Laparoscopic nephrectomy of a cross-fused ectopic kidney in a child with hypertension.

OBJECTIVE: We report a case of laparoscopic nephrectomy of a cross-fused ectopic kidney in a 4-year-old girl with renal hypertension and Fanconi anemia. MATERIALS AND METHODS: We performed a transperitoneal laparoscopy. Ectopic kidney resection was done after dissection of the pathological kidney and after clamping vessels, using an ultrasonic device. Hospitalization time was 4 days. RESULTS: At 6 months, blood pressure was normalized and the patient showed an adequate growth curve. CONCLUSION: The transperitoneal route is very effective when a nephrectomy is necessary. It offers perfect exposure with limited risk of complications.