Renal Sympathetic Denervation: A Viable Option for Treating Resistant Hypertension

Taming resistant hypertension: The promise of novel pharmacologic approaches and renal denervation

Resistant hypertension is associated with an exceedingly high cardiovascular risk and there remains an unmet therapeutic need driven by pathophysiologic pathways unaddressed by guideline-recommended therapy. While spironolactone is widely considered as the preferable fourth-line drug, its broad application is limited by its side effect profile, especially off-target steroid receptor-mediated effects and hyperkalaemia in at-risk subpopulations. Recent landmark trials have reported promising safety and efficacy results for a number of novel compounds targeting relevant pathophysiologic pathways that remain unopposed by contemporary drugs. These include the dual endothelin receptor antagonist, aprocitentan, the aldosterone synthase inhibitor, baxdrostat and the nonsteroidal mineralocorticoid receptor antagonist finerenone. Furthermore, the evidence base for consideration of catheter-based renal denervation as a safe and effective adjunct therapeutic approach across the clinical spectrum of hypertension has been further substantiated. This review will summarise the recently published evidence on novel antihypertensive drugs and renal denervation in the context of resistant hypertension.

The Preliminary Outcome of Laser-Assisted Angioplasty Combined with Endovascular Radiofrequency Ablation for Thromboangiitis Obliterans

INTRODUCTION

Endovascular therapies have not yet had an ideal effect on thromboangiitis obliterans (TAO) and no data have been published about laser-assisted angioplasty (LA) combined with radiofrequency ablation (RFA) for TAO. This study aimed to investigate the outcome of LA combined with RFA for TAO.

METHODS

Sixteen consecutive patients underwent LA and RFA procedures between June 2018 and March 2019 in this prospective pilot study. The clinical outcomes and complications were assessed at 6, 12, and 18 months after the procedure. The primary endpoint was defined as the limb salvage rate and freedom of target-lesion revascularization (f-TLR) of the limb, and the effect on the outcome was assessed by the ankle brachial index (ABI), numerical rating scores (NRSs), and the EuroQol Group 5-Dimension Self-Report Questionnaire (EQ-5D).

RESULTS

Men accounted for 87.5% of the patients. All patients underwent LA, and following the RFA procedure, two patients received bailout stenting (12.50%). The technique success rate was 100%, and no severe complications occurred. The ABI was significantly higher at the 18-month follow-up than at baseline (P < 0.001). The primary and secondary patency rates were 71.82% and 79.80%, respectively, and the f-TLR and limb salvage rates were 90% and 92.86% based on Kaplan-Meier analysis. The EQ-5D value was higher after the procedure than at baseline (P < 0.001), and the NRS value was lower after the procedure than at baseline (P < 0.001).

CONCLUSIONS

Our results confirmed that LA combined with RFA was a feasible procedure that resulted in acceptable limb salvage and f-TLR rates.

Recent advances in understanding and managing resistant/refractory hypertension

The management of resistant hypertension presents several challenges in everyday clinical practice. During the past few years, several studies have been performed to identify efficient and safe pharmacological and non-pharmacological options for the management of such patients. The Spironolactone versus placebo, bisoprolol, and doxazosin to determine the optimal treatment for drug-resistant hypertension (PATHWAY-2) trial demonstrated significant benefits with the use of spinorolactone as a fourth-line drug for the treatment of resistant hypertension over doxazosin and bisoprolol. In addition, recent data support that spironolactone may demonstrate superiority over central acting drugs in such patients, as well. Based on the European guidelines, spironolactone is recommended as the fourth-line drug option, followed by amiloride, other diuretics, doxazosin, bisoprolol or clonidine.  Among several device-based approaches, renal sympathetic denervation had fallen into hibernation after the disappointing results of the Renal Denervation in Patients With Uncontrolled Hypertension (SYMPLICITY HTN) 3 trial. However, the technique re-emerged at the epicenter of the clinical and research interest after the favorable results of three sham-controlled studies, which facilitated novel catheters and techniques to perform the denervation. Significant results of iliac anastomosis on blood pressure levels have also been demonstrated. Nevertheless, the technique-related adverse events resulted in withdrawal of this interventional approach. Last, the sympatholytic properties of the carotid baroreceptor activation therapy were associated with significant blood pressure reductions in patients with resistant hypertension, which need to be verified in larger controlled trials. Currently device-based approaches are recommended only in the setting of clinical trials until more safety and efficacy data become available.

Renal denervation attenuates pressure overload-induced cardiac remodelling in rats with biphasic regulation of autophagy

AIM

This study aimed to investigate effects of renal denervation (RDN) on pressure overload-induced cardiac remodelling in rats and the related mechanisms.

METHODS

Adult male Sprague-Dawley rats underwent transverse aortic constriction (TAC) to generate cardiac remodelling. RDN was performed 1 week after TAC. The animals were divided into four groups: control group, TAC group, TAC+RDN group and control+RDN group. Rats in all groups were studied at 3 and 10 weeks after TAC respectively. Echocardiography and histology were used to evaluate cardiac function and pathological changes. TUNEL staining and western blotting were used to assess apoptosis. Western blotting and transmission electron microscopy (TEM) were used to evaluate autophagy.

RESULTS

Three weeks after TAC, the TAC rats exhibited cardiac hypertrophy with normal cardiac function and no myocardial interstitial fibrosis or apoptosis, accompanied by a lower LC3 II level and fewer autophagic vacuoles in the left ventricles, both in the presence and absence of chloroquine (CQ), indicating suppressed autophagy at this stage. RDN ameliorated these pathological changes and attenuated the decrease in autophagy. Ten weeks after TAC, the TAC rats had decreased cardiac function, obvious cardiac interstitial fibrosis and apoptosis, with increased autophagy. RDN prevented these pathological changes, coincident with attenuation of increased autophagy.

CONCLUSION

Autophagy was suppressed at the early stage but activated at the late stage of TAC-induced cardiac remodelling. RDN attenuated the pathological changes of TAC rats, accompanied by attenuation of the changes in autophagy. Thus, RDN ameliorated TAC-induced cardiac remodelling partially associated with biphasic modulation of autophagy.

Resistant Hypertension: Which Agent?

Resistant hypertension is commonly defined as office blood pressure above recommended target despite the use of optimal doses of at least three antihypertensive drugs including a diuretic. Australian guidelines recommend combination of blockers of the renin-angiotensin system, either ACE inhibitors or angiotensin receptor blockers, with calcium channel blockers and diuretics as the preferred triple therapy. A substantial proportion of hypertensive patients will require additional pharmacotherapy to achieve or get close to target blood pressure levels. Here we briefly review the evidence currently available to provide guidance on the most appropriate choice for additional antihypertensive pharmacotherapy and touch on interventional approaches that may be considered in some patients.