Renal denervation in a patient with prior renal artery stenting

2022 Renal denervation therapy for the treatment of hypertension: a statement from the Thai Hypertension Society

Hypertension remains a significant risk factor for major cardiovascular events worldwide. Poor adherence to treatment is extremely common in clinical practice, leading to uncontrolled hypertension. However, some patients with resistant hypertension still have uncontrolled blood pressure despite good medical compliance. A specific group of patients also develop adverse reactions to many blood pressure-lowering medications. These scenarios indicate that innovative strategies to lower blood pressure in challenging cases of hypertension are needed. The blood pressure-lowering efficacy of catheter-based renal denervation therapy to decrease sympathetic tone has been confirmed in many publications in recent years. Apart from both the invasiveness and the expensiveness of this technology, appropriate case selection to undergo this procedure is still developing. The utilization of renal denervation therapy for hypertension treatment in Thailand has lasted for 10 years with a good response in most cases. Currently, only certain interventionists at a few medical schools in Thailand can perform this procedure. However, more physicians are now interested in applying this technology to their patients. The Thai Hypertension Society Committee has reviewed updated information to provide principles for the appropriate utilization of renal denervation therapy. The blood pressure-lowering mechanism, efficacy, suitable patient selection, pre- and postprocedural assessment and procedural safety of renal denervation are included in this statement.

Treatment of atrial fibrillation in patients with enhanced sympathetic tone by pulmonary vein isolation or pulmonary vein isolation and renal artery denervation: clinical background and study design : The ASAF trial: ablation of sympathetic atrial fibrillation

BACKGROUND

Hypertension is an important, modifiable risk factor for the development of atrial fibrillation (AF). Even after pulmonary vein isolation (PVI), 20-40% experience recurrent AF. Animal studies have shown that renal denervation (RDN) reduces AF inducibility. One clinical study with important limitations suggested that RDN additional to PVI could reduce recurrent AF.

OBJECTIVE

The goal of this multicenter randomized controlled study is to investigate whether RDN added to PVI reduces AF recurrence.

METHODS

The main end point is the time until first AF recurrence according to EHRA guidelines after a blanking period of 3 months. Assuming a 12-month accrual period and 12 months of follow-up, a power of 0.80, a two-sided alpha of 0.05 and an expected drop-out of 10% per group, 69 patients per group are required. We plan to randomize a total of 138 hypertensive patients with AF and signs of sympathetic overdrive in a 1:1 fashion. Patients should use at least two antihypertensive drugs. Sympathetic overdrive includes obesity, exercise-induced excessive blood pressure (BP) increase, significant white coat hypertension, hospital admission or fever induced AF, tachycardia induced AF and diabetes mellitus. The interventional group will undergo PVI + RDN and the control group will undergo PVI.

RESULTS

Patients will have follow-up for 1 year, and continuous loop monitoring is advocated.

CONCLUSION

This randomized, controlled study will elucidate if RDN on top of PVI reduces AF recurrence.

Renal Denervation: A Novel Therapy at the Crossroads of Imaging, Intervention, and Innovation

Hypertension (HTN) is one of the most significant medical problems affecting society today. The estimated 76 million Americans with hypertension represent a significant public health problem, contributing to cardiac, vascular, renal, and neurovascular morbidity and mortality. HTN is the most common indication for lifelong pharmacologic treatment, mainly because of the incontrovertible reductions in cardiovascular events with blood pressure (BP) reduction and control. However, despite the availability and potency of multiple different antihypertensive drugs, up to half of American patients have BPs above the recommended target. Given the overwhelming evidence of both the cost to society of HTN and the benefits that are accrued from improved BP control, alternatives or adjuncts to current management options have been sought to aid in treatment of these patients. Over the past few years, a device-based approach involving modulation of the autonomic nervous system, termed renal denervation, has evolved to meet this challenge. With early trials showing startlingly good results, with few side effects, multiple devices were fast-tracked to clinical trials and hence to the market. However, larger trials have shone an unfavorable light on the field, with concerns about the short- and long-term effectiveness, diverting attention back to operational and procedural details. Despite this, image-guided manipulation of the sympathetic nervous system to treat HTN remains a fertile area of laboratory and clinical research.

Renal denervation for hypertension refractory to renal artery stenting

PURPOSE

To investigate the effect of renal denervation (RDN) on blood pressure and renal function in refractory hypertension after renal artery recanalization and optimal medical therapy.

METHODS

Ten patients (6 women; mean age 70.0±5.1 years) with an office systolic blood pressure >160 mmHg despite taking ≥3 antihypertensive drugs and uni- or bilateral renal artery stenting were treated with RDN. Radiofrequency (RF) energy was delivered to the native segment of the artery keeping a 5-mm safe distance from the stented segments. Standardized office (OBP) and ambulatory (ABP) blood pressure measurements, medication, and renal assessment, including renal duplex ultrasound and renal function, were determined at baseline and on follow-up to 12 months.

RESULTS

OBP (systolic/diastolic) at baseline was 190.0±20.4 / 84.2±10.1 mmHg. It decreased to 171.1±28.7* / 82.2±8.7, 165.5±28.4(†) / 76.1±7.4, and 158.3±14.2(†) / 75.5±9.5(†) mmHg (*p<0.001; (†)p<0.01) at 3, 6, and 12 months after RDN, respectively. Average ABP (systolic/diastolic) after 6 and 12 months decreased by -7.6(‡) / -3.1 and -11.3(‡) / -5.1(‡) mmHg ((‡)p<0.05). There was no renal artery (re)stenosis, dissection, or aneurysm within 12 months. Creatinine, cystatin C, and glomerular filtration rate remained unchanged. Urine albumin excretion decreased in 4/10 patients. Renal resistive indices improved in native, but not in stented renal arteries within the follow-up period.

CONCLUSION

This proof-of-concept study demonstrates that RF-based RDN can be safely and effectively delivered in patients with resistant hypertension and previous renal artery stenting.

Efficacy and Safety of Catheter-Based Radiofrequency Renal Denervation in Stented Renal Arteries

Background—

In selected patients with hypertension, renal artery (RA) stenting is used to treat significant atherosclerotic stenoses. However, blood pressure often remains uncontrolled after the procedure. Although catheter-based renal denervation (RDN) can reduce blood pressure in certain patients with resistant hypertension, there are no data on the feasibility and safety of RDN in stented RA.

Methods and Results—

We report marked blood pressure reduction after RDN in a patient with resistant hypertension who underwent previous stenting. Subsequently, radiofrequency ablation was investigated within the stented segment of porcine RA, distal to the stented segment, and in nonstented RA and compared with stent only and untreated controls. There were neither observations of thrombus nor gross or histological changes in the kidneys. After radiofrequency ablation of the nonstented RA, sympathetic nerves innervating the kidney were significantly reduced, as indicated by significant decreases in sympathetic terminal axons and reduction of norepinephrine in renal tissue. Similar denervation efficacy was found when RDN was performed distal to a renal stent. In contrast, when radiofrequency ablation was performed within the stented segment of the RA, significant sympathetic nerve ablation was not seen. Histological observation showed favorable healing in all arteries.

Conclusions—

Radiofrequency ablation of previously stented RA demonstrated that RDN provides equally safe experimental procedural outcomes in a porcine model whether the radiofrequency treatment is delivered within, adjacent, or without the stent struts being present in the RA. However, efficacious RDN is only achieved when radiofrequency ablation is delivered to the nonstented RA segment distal to the stent.

Renal denervation in treatment-resistant hypertension: the need for restraint and more and better evidence

The Symplicity studies suggest that intravascular renal sympathetic nervous denervation improves blood pressure in patients with resistant hypertension, thus potentially opening a market for devices to be used when conventional drug therapy fails to restore blood pressure control. However, the size and durability of the antihypertensive, renal and sympatholytic effects of renal denervation, the long-term safety, improvement of quality of life, the possibility to relax antihypertensive drug treatment, the cost-effectiveness, and long-term hard cardiovascular-renal outcomes still remain to be firmly established. Most ongoing studies are small, industry-driven and purely observational with objectives to test new catheters and source of energy for renal nerve ablation or to search for ancillary benefits and new indications of the technique. The most urgent need, that is adequately powered randomized clinical trials testing renal denervation versus usual medical therapy delivered according to the state-of-the-art are under-represented and seldom funded by industry. The authors make a plea for a coordinated research effort in Europe. With this objective, they established collaboration with leading European experts and started the European Network for Coordinating Research on Renal Denervation. In the meantime, renal denervation should remain the ultima ratio in adherent and truly resistant patients with severe hypertension, confirmed by ambulatory monitoring, in whom secondary hypertension has been excluded and in whom all other efforts to reduce blood pressure have failed.

Renal Denervation

Resistant hypertension, defined as failure to reach blood pressure (BP) goals despite treatment with ≥3 antihypertensive agents, one of which is a diuretic, bears a significant risk of cardiovascular complications. Strong evidence exists, implicating the overactivation of the sympathetic nervous system (SNS) in the pathogenesis of resistant hypertension through complex neurohormonal interactions. Renal denervation is a novel attractive option to achieve adequate blockade of the sympathetic system, with subsequent BP reductions in patients with resistant hypertension. Data have shown promising results regarding the efficacy of the procedure, maintaining a favorable safety profile. As such, the paradigm of resistant hypertension has expanded in other conditions involving a hyperadrenergic state such as the metabolic syndrome, heart failure, arrhythmias, sleep apnea, and renal failure. This review focuses on the pathophysiological rationale of modifying SNS tone and the evidence of the benefits of such intervention beyond BP control.