Resistant Hypertension

Controversies related to renal artery denervation and devices

PURPOSE OF REVIEW

This review article discusses the controversies, strengths, and limitations of the current literature on renal artery denervation in the management of resistant hypertension, as well as the future directions of this intervention.

RECENT FINDINGS

There have been conflicting data from the different randomized control trials assessing the efficacy of renal artery denervation in the management of resistant hypertension.

SUMMARY

Renal artery denervation is achieved by ablating the sympathetic nerves surrounding the renal arteries using endovascular ultrasound, radiofrequency, or alcohol. Our review article highlights that renal artery denervation is generally effective in improving blood pressure in patients with resistant hypertension. The Food and Drug Administration (FDA) has recently approved the ReCor Medical Paradise system, and the Symplicity Spyral RDN systems for renal artery denervation.

Blood Pressure Intervention and Control in SPRINT

BACKGROUND

The SPRINT (Systolic Blood Pressure Intervention Trial) demonstrated reductions in major cardiovascular disease events and mortality with an intensive systolic blood pressure (SBP) goal intervention. However, a detailed description of the blood pressure intervention, antihypertensive medication usage, blood pressure levels, and rates and predictors of blood pressure control has not been reported previously.

METHODS

Hypertensive participants (n=9361) 50 years and older with elevated cardiovascular disease risk were randomized 1:1 to SBP goal <120 mm Hg or SBP goal <140 mm Hg. Guideline-recommended antihypertensive medications and dosing were provided at no cost. Intensive group participants were started on at least 2 medications, and medications were adjusted monthly until SBP goal was achieved, if feasible. Standard group participants were treated to achieve SBP 135 to 139 mm Hg.

RESULTS

Baseline blood pressure (median±interquartile range) was 138±19/78±16 mm Hg. For intensive group participants, percent at goal rose from 8.9% at baseline to 52.4% at 6 months and average antihypertensive medications rose from 2.2 to 2.7; SBP was <120 mm Hg in 61.6% and <130 mm Hg in 80.0% at their final visit. For the standard group participants, percent at goal rose from 53.0% at baseline to 68.6% at 6 months, while antihypertensive medications fell from 1.9 to 1.8. From 6 to 36 months, median SBP was stable at 119±14 mm Hg for intensive and 136±15 mm Hg for standard participants, with stable numbers of medications. Few predictors of SBP control were found in multiple regression models.

CONCLUSIONS

These results may inform and help replicate the benefits of SPRINT in clinical practice.

REGISTRATION

URL: http://www.

CLINICALTRIALS

gov; Unique identifier: NCT01206062.

Patiromer versus placebo to enable spironolactone use in patients with resistant hypertension and chronic kidney disease (AMBER): results in the pre-specified subgroup with heart failure

Aims

The AMBER trial demonstrated that concomitant use of patiromer enabled the more persistent use of spironolactone by reducing the risk of hyperkalaemia in patients with resistant hypertension and advanced chronic kidney disease. We report herein the pre‐specified subgroup analysis in patients with heart failure (HF).

Methods and results

Participants were randomly assigned (1:1) to receive either placebo or patiromer (8.4 g once daily), in addition to open‐label spironolactone (starting at 25 mg once daily) and their baseline blood pressure medications. Dose titrations were permitted after 1 week for patiromer/placebo and after 3 weeks for spironolactone. The primary endpoint was the between‐group difference at week 12 in the proportion of patients on spironolactone. Efficacy endpoints and safety were assessed in all randomized patients (intention to treat). A total of 295 patients were enrolled, of whom 132 (45%) had HF. In the HF subgroup, 68.1% of patients receiving placebo remained on spironolactone at week 12, compared with 84.1% of patients receiving patiromer (P = 0.0504). The reason for discontinuation from spironolactone use was hyperkalaemia in the majority of both groups. There was no significant interaction between the subgroups with HF and without HF (P = 0.8085) for the primary endpoint.

Conclusions

Consistent with the overall AMBER trial results, this pre‐specified subgroup analysis in patients with HF, resistant hypertension and advanced chronic kidney disease demonstrated that patiromer enabled more persistent use of spironolactone by reducing the risk of hyperkalaemia.

Intensive Blood Pressure Treatment for Resistant Hypertension

Supplemental Digital Content is available in the text.

Evidence about the target blood pressure (BP) in patients with resistant hypertension is limited. The present study aimed to assess the efficacy of intensive BP treatment (systolic BP target, <120 mm Hg) versus standard BP treatment (systolic BP target, <140 mm Hg) in patients with resistant hypertension. This is a secondary analysis using data from SPRINT (Systolic Blood Pressure Intervention Trial). This study included 1397 patients with resistant hypertension and 7698 without resistant hypertension. Using the Cox proportional hazards model, we compared time to first occurrence of a major adverse cardiovascular event (cardiovascular death, myocardial infarction, and stroke) between the intensive and standard BP treatment groups. Mean follow-up was 3.1 years; major adverse cardiovascular events was confirmed in 381 patients. Risk of major adverse cardiovascular events was significantly lower in the intensive treatment group than in the standard treatment group (hazard ratio, 0.62; 95% CI, 0.40–0.96; P=0.03). Risks of all-cause and cardiovascular death in patients with resistant hypertension were also significantly lower in the intensive treatment group than in the standard treatment group (hazard ratio for all-cause death: 0.60; 95% CI, 0.38–0.97; P=0.03; hazard ratio for cardiovascular death: 0.34; 95% CI, 0.15–0.81; P=0.01). Similar associations were observed in various subgroups. Intensive BP treatment was significantly associated with a decreased risk of major adverse cardiovascular events in patients with resistant hypertension.

Impact of the SPRINT Trial on Hypertension Management

The Systolic Blood Pressure Intervention Trial is the first large prospective randomized controlled trial to demonstrate the benefit of an intensive systolic blood pressure (SBP) treatment target (<120 mm Hg) compared to a standard target (<140 mm Hg) in reducing cardiovascular morbidity and mortality and all-cause mortality in high-risk hypertensive patients. The impact of SPRINT on hypertension treatment has been large, but major questions remain about the feasibility of achieving the SPRINT intensive SBP target in routine practice, the generalizability of the SPRINT findings to hypertensive populations that were excluded from the trial, and the cost effectiveness of adopting the SPRINT intensive treatment goal. In this review, we discuss the generalizability of SPRINT data to the general population of adults with hypertension and with various comorbidities, the cost effectiveness of intensive SBP-lowering therapy, and the implications of SPRINT for future hypertension guideline development and clinical practice.

Baroreceptors in the carotid and hypertension-systematic review and meta-analysis of the effects of baroreflex activation therapy on blood pressure

Activation of baroreceptors in the carotid modulates the autonomic nervous system. Baroreflex activation therapy (BAT), which activates baroreceptors in the carotid, has become available in the treatment of resistant hypertension. Besides this, a carotid implant modulating baroreceptors as well as pharmacological modulation of carotid bodies were quite recently presented. This review will underscore currently available and promising approaches that activate baroreceptors in the carotid, and thereby contribute to beneficial effects in patients with arterial hypertension, and discusses potential organoprotective BAT effects beyond blood pressure (BP) reduction. A systematic review and meta-analysis was conducted including observational studies or randomized controlled trials that investigated the effect of BAT on BP in resistant hypertension. Nine studies, seven observational and two randomized, with a total of 444 patients, were included in the evaluation. Analysing the longest follow-up visit from the different studies, there was a significant reduction of systolic BP after BAT of -36 mmHg [95% confidence interval (CI) -42 to -30 mmHg]. Separate meta-analysis of the short-term (1-6 months) and long-term effects (≥12 months) revealed a reduction of -21 mmHg (95% CI -26 to -17 mmHg) and -38 mmHg (95% CI -46 to -30 mmHg), respectively. There are promising data both in the experimental and the clinical application for BAT. Though the present meta-analysis suggests beneficial effects of BAT on BP, the results must be interpreted extremely carefully. Considering that evidence from controlled trials is very limited, it is evident that there is a strong need for further investigation.

Resistant hypertension in elderly: a clinical manifestation of heart failure with preserved ejection fraction? retrospective single-center analysis

Background: Resistant hypertension (RHT) is defined as high blood pressure despite three antihypertensive medications one being a diuretic. RHT is a common clinical problem and as a subgroup has not been studied widely. The present study has investigated patient demographics and if the RHT might be a clinical presentation of heart failure with preserved ejection fraction (HFPEF) in elderly. Method: The outpatient data between January and June 2015 of Izmir Kemalpasa State hospital's hypertension specialty clinic has been reviewed retrospectively. The patients with pseudo-RHT are excluded. Among 957 patients, 68 patients have been identified as true RHT with a left ventricle ejection fraction ≥50%. HFPEF is defined according to the latest guideline. Instead of a common cut-off level for NT-proBNP, age and gender-related cut-off levels have been used. Results: The mean age was 63.24 ± 12.05 years. Among 68 patients, 49 were female. While only 3 patients in younger group (8.8%) had elevated levels of NT-proBNP, 22 of older RHT patients (64.7%) had high levels. NT-proBNP levels were disproportionally high in elderly (p < 0.001) and high levels in RHT patients were related to a larger left atrial diameter (p < 0.001). Conclusion: The underlying mechanism might be different in RHT according to age. Hypervolemia might be the key factor in older RHT patients but not in younger patients. The current study suggests RHT in elderly can be a clinical presentation of HFPEF, and they should be investigated and treated accordingly. Because of single-center results and limited patients, further studies are needed.

Uncontrolled hypertension increases risk of all-cause and cardiovascular disease mortality in US adults: the NHANES III Linked Mortality Study

Clinical trials had provided evidence for the benefit effect of antihypertensive treatments in preventing future cardiovascular disease (CVD) events; however, the association between hypertension, whether treated/untreated or controlled/uncontrolled and risk of mortality in US population has been poorly understood. A total of 13,947 US adults aged ≥18 years enrolled in the Third National Health and Nutrition Examination Survey (1988–1994) were used to conduct this study. Mortality outcome events included all-cause, CVD-specific, heart disease-specific and cerebrovascular disease-specific deaths, which were obtained from linked 2011 National Death Index (NDI) files. During a median follow-up of 19.1 years, there were 3,550 all-cause deaths, including 1,027 CVD deaths. Compared with normotensives, treated but uncontrolled hypertensive patients were at higher risk of all-cause (HR = 1.62, 95%CI = 1.35–1.95), CVD-specific (HR = 2.23, 95%CI = 1.66–2.99), heart disease-specific (HR = 2.19, 95%CI = 1.57–3.05) and cerebrovascular disease-specific (HR = 3.01, 95%CI = 1.91–4.73) mortality. Additionally, untreated hypertensive patients had increased risk of all-cause (HR = 1.40, 95%CI = 1.21–1.62), CVD-specific (HR = 1.77, 95%CI = 1.34–2.35), heart disease-specific (HR = 1.69, 95%CI = 1.23–2.32) and cerebrovascular disease-specific death (HR = 2.53, 95%CI = 1.52–4.23). No significant differences were identified between normotensives, and treated and controlled hypertensives (all p > 0.05). Our study findings emphasize the benefit of secondary prevention in hypertensive patients and primary prevention in general population to prevent risk of mortality later in life.

Effect of the physical activity program on the treatment of resistant hypertension in primary care

BACKGROUND

Regular physical activity is widely recommended for patients with arterial hypertension as an essential component of lifestyle modification. Much less is known about the impact of physical exercise on the management of treatment of resistant hypertension (RH). The aim was to assess the effect of physical activity program intensified by mobile phone text reminders on blood pressure control in subjects with RH managed in the primary care.

METHODS

In total, 53 patients with primary hypertension were qualified, including 27 who met the criteria for RH and 26 with well-controlled hypertension (WCH). Ambulatory 24-h blood pressure was monitored and body composition evaluated with bioimpedance and habitual physical activity profile was determined continuously over 72 h with accelerometer. All measurements were performed at baseline and after three and six months. The patients were asked to modify their lifestyle according to American Heart Association Guidelines that included regular aerobic physical activity tailored to individual needs.FindingsPhysical activity in RH increased significantly after six months compared with control subjects (P=0.001). Office systolic blood pressure (SBP) and diastolic blood pressure (DBP) in the RH group decreased significantly after three months but after six months only office DBP remained significantly lower. After three months 24-h SBP decreased by 3.1±11 mmHg (P=0.08) and DBP by 2.0±6 mmHg (P=0.17) in RH, whereas in WCH respective changes were +1.2±10 and -0.3±6 mmHg. After six months 24-h BP changes were similar.

CONCLUSION

Individualized structured physical activity program increases physical activity in the treatment of resistant hypertensives in primary care but the effect on 24-h blood pressure is only transient.

Eplerenone-Resistant Salt-Sensitive Hypertension in Nedd4-2 C2 KO Mice

The epithelial sodium channel (ENaC) plays critical roles in maintaining fluid and electrolyte homeostasis and is located in the aldosterone-sensitive distal nephron (ASDN). We previously found that Nedd4-2 C2 knockout (KO) mice showed salt-sensitive hypertension with paradoxically enhanced ENaC gene expression in ASDN under high oral salt intake. Eplerenone (EPL), a selective aldosterone blocker, is a promising therapeutic option for resistant or/and salt-sensitive hypertension. We examined the effect of EPL on Nedd4-2 C2 KO mice with respect to blood pressure, metabolic parameters, and molecular level changes in ASDN under high oral salt intake. We found that EPL failed to reduce blood pressure in KO mice with high oral salt intake and upregulated ENaC expression in ASDN. Thus, salt-sensitive hypertension in Nedd4-2 C2 KO was EPL-resistant. Gene expression analyses of laser-captured specimens in ASDN suggested the presence of non-aldosterone-dependent activation of ENaC transcription in ASDN of Nedd4-2 C2 KO mice, which was abolished by amiloride treatment. Our results from Nedd4-2 C2 KO mice suggest that enhanced ENaC gene expression is critically involved in salt-sensitive hypertension under certain conditions of specific enzyme isoforms for their ubiquitination.