Predictors of blood pressure response: Obesity is associated with a less pronounced treatment response after renal denervation

Predicting blood pressure response to renal denervation based on a new approach

BACKGROUND

Identifying predictors of blood pressure (BP) response to renal denervation (RDN) is crucial for patient selection. According to Wilder's principle, baseline BP predicts BP change after any antihypertensive intervention. Thus, any observed BP change after RDN is the sum of the BP change depending on the baseline BP and the specific BP reduction due to RDN. Based on this concept, we propose a new definition of BP responders.

METHODS

In our center, 148 patients with uncontrolled hypertension underwent RDN, and 24-h ambulatory BP (ABP) was measured at baseline, and 6 months after the procedure. The decrease in 24-h systolic BP (SBP) correlated with baseline SBP (P = <0.001, r = -0.374). We determined the RDN-specific effect by subtracting the predicted SBP decrease from the observed SBP decrease. The cohort was divided into RDN responders, neutral responders, and nonresponders.

RESULTS

Our study population had a mean age of 59 ± 10.4 years and was 74% male. The RDN-specific (residual) 24-h ABP decreased by -14.9 ± 6.3/-8.2 ± 3.8 mmHg (responder group), 1.0 ± 3.2/0.2 ± 1.9 mmHg (neutral group), and 14.2 ± 10.4/8.3 ± 3.9 mmHg (nonresponder group) 6 months after RDN. Responders had fewer antihypertensive medications (P = 0.018), higher baseline office heart rate (HR) (P = 0.019), higher 24-h ambulatory HR (P = 0.003), lower BMI (P < 0.038), and absence of type 2 diabetes (T2D) (P = 0.020).

CONCLUSION

Our definition of BP responders to RDN separates baseline BP-related changes from RDN-specific changes. Positive predictors for BP response to RDN include low BMI, fewer antihypertensive medications, high baseline office HR, high 24-h ambulatory HR, and absence of T2D.

Patient-Specific Factors Predicting Renal Denervation Response in Patients With Hypertension: A Systematic Review and Meta-Analysis

BACKGROUND

The accurate selection of patients likely to respond to renal denervation (RDN) is crucial for optimizing treatment outcomes in patients with hypertension. This systematic review was designed to evaluate patient-specific factors predicting the RDN response.

METHODS AND RESULTS

We focused on individuals with hypertension who underwent RDN. Patients were categorized based on their baseline characteristics. The primary outcome was blood pressure (BP) reduction after RDN. Both randomized controlled trials and nonrandomized studies were included. We assessed the risk of bias using corresponding tools and further employed the Grading of Recommendations Assessment, Development, and Evaluation approach to assess the overall quality of evidence. A total of 50 studies were ultimately included in this systematic review, among which 17 studies were for meta-analysis. Higher baseline heart rate and lower pulse wave velocity were shown to be associated with significant antihypertensive efficacy of RDN on 24-hour systolic BP reduction (weighted mean difference, -4.05 [95% CI, -7.33 to -0.77]; weighted mean difference, -7.20 [95% CI, -9.79 to -4.62], respectively). In addition, based on qualitative analysis, higher baseline BP, orthostatic hypertension, impaired baroreflex sensitivity, and several biomarkers are also reported to be associated with significant BP reduction after RDN.

CONCLUSIONS

In patients with hypertension treated with the RDN, higher heart rate, and lower pulse wave velocity were associated with significant BP reduction after RDN. Other factors, including higher baseline BP, hypertensive patients with orthostatic hypertension, BP variability, impaired cardiac baroreflex sensitivity, and some biomarkers are also reported to be associated with a better BP response to RDN.

Present Evidence of Determinants to Predict the Efficacy of Renal Denervation

Sympathetic overactivation is one of the main contributors to development and progress of hypertension. Renal denervation (RDN) has been evidenced by series of clinical trials for its efficacy and safety to treat overactivated sympathetic nervous system induced diseases. However, the results were inconsistent and not all patients benefited from RDN. Appropriate patient selection and intraoperative factors to improve the efficacy of RDN need to be solved urgently. Over the decade, research studies on the correlations between indicators and the antihypertensive effects have been conducted and made a fairly well progress. Herein, we comprehensively reviewed the research studies on how to make RDN more predictable or improve the efficacy of RDN and summarized these potential indicators or devices which might be applied in clinical settings.

Predictors for success in renal denervation-a single centre retrospective analysis

Renal denervation (RDN) is one of the most frequently used invasive methods for the treatment of arterial hypertension. However, recent randomized sham-controlled studies raised concern about the efficacy and predictability of response. We retrospectively analyzed outcomes of patients, who underwent RDN in our hypertension center between November 2010 and April 2014 and report here outcomes twelve months after procedure based on 24-hours ambulatory blood pressure monitoring. We defined ten-mm Hg decrease in office systolic blood pressure (SBP) as a cut-off for response and looked for possible predictors of this response using binary multiple regression analysis. 42 patients were included. Their mean age was 59.6 ± 9.2 years and 24% were female. Baseline office SBP and diastolic blood pressure (DBP) were 164.1 ± 20.3 and 91.8 ± 12.4 mm Hg respectively. Mean 24 h-SBP significantly decreased from 149.8 ± 13.3 mm Hg to 141.2 ± 14.6 mm Hg. Mean 24 h-DBP significantly decreased from 83.3 ± 11.7 mm Hg to 78.8 ± 11.2 mm Hg. A higher level of mean 24 h-DBP and office DBP was shown to be predictive for response in office BP and a higher level of mean 24 h-DBP for response in 24 h-SBP and 24 h-DBP. Further properly designed randomized trials are warranted to confirm this finding as well as further investigate the role of diabetes mellitus and arterial stiffness in RDN.

Predictive factors for successful renal denervation: should we use them in clinical trials?

Renal denervation (RDN) is facing various challenges to its initial claimed value in hypertension treatment. Major concerns are the choice of the patients and the technical efficacy of the RDN. Different factors have been described as predicting the capacity of RDN to decrease blood pressure. These factors are related to the patients, the procedure and the tools to confirm successful neural ablation. Their use in future trials should help to improve RDN trials understanding and outcomes. This review summarizes the different predictive factors available and their potential benefits in patient selection and in procedure guidance.

The Role of the Autonomic Nervous System in the Pathophysiology of Obesity

Obesity is reaching epidemic proportions globally and represents a major cause of comorbidities, mostly related to cardiovascular disease. The autonomic nervous system (ANS) dysfunction has a two-way relationship with obesity. Indeed, alterations of the ANS might be involved in the pathogenesis of obesity, acting on different pathways. On the other hand, the excess weight induces ANS dysfunction, which may be involved in the haemodynamic and metabolic alterations that increase the cardiovascular risk of obese individuals, i.e., hypertension, insulin resistance and dyslipidemia. This article will review current evidence about the role of the ANS in short-term and long-term regulation of energy homeostasis. Furthermore, an increased sympathetic activity has been demonstrated in obese patients, particularly in the muscle vasculature and in the kidneys, possibily contributing to increased cardiovascular risk. Selective leptin resistance, obstructive sleep apnea syndrome, hyperinsulinemia and low ghrelin levels are possible mechanisms underlying sympathetic activation in obesity. Weight loss is able to reverse metabolic and autonomic alterations associated with obesity. Given the crucial role of autonomic dysfunction in the pathophysiology of obesity and its cardiovascular complications, vagal nerve modulation and sympathetic inhibition may serve as therapeutic targets in this condition.

Renal sympathetic denervation in therapy resistant hypertension - pathophysiological aspects and predictors for treatment success

Many forms of human hypertension are associated with an increased systemic sympathetic activity. Especially the renal sympathetic nervous system has been found to play a prominent role in this context. Therefore, catheter-interventional renal sympathetic denervation (RDN) has been established as a treatment for patients suffering from therapy resistant hypertension in the past decade. The initial enthusiasm for this treatment was markedly dampened by the results of the Symplicity-HTN-3 trial, although the transferability of the results into clinical practice to date appears to be questionable. In contrast to the extensive use of RDN in treating hypertensive patients within or without clinical trial settings over the past years, its effects on the complex pathophysiological mechanisms underlying therapy resistant hypertension are only partly understood and are part of ongoing research. Effects of RDN have been described on many levels in human trials: From altered systemic sympathetic activity across cardiac and metabolic alterations down to changes in renal function. Most of these changes could sustainably change long-term morbidity and mortality of the treated patients, even if blood pressure remains unchanged. Furthermore, a number of promising predictors for a successful treatment with RDN have been identified recently and further trials are ongoing. This will certainly help to improve the preselection of potential candidates for RDN and thereby optimize treatment outcomes. This review summarizes important pathophysiologic effects of renal denervation and illustrates the currently known predictors for therapy success.

Can we predict the blood pressure response to renal denervation?

Renal denervation (RDN) is a new therapy used to treat drug-resistant hypertension in the clinical setting. Published human trials show substantial inter-individual variability in the blood pressure (BP) response to RDN, even when technical aspects of the treatment are standardized as much as possible between patients. Widespread acceptance of RDN for treating hypertension will require accurate identification of patients likely to respond to RDN with a fall in BP that is clinically significant in magnitude, well-maintained over time and does not cause adverse consequences. In this paper we review and evaluate clinical studies that address possible predictors of the BP response to RDN. We conclude that only one generally reliable predictor has been identified to date, namely pre-RDN BP level, although there is some evidence for a few other factors. Experimental interventions in laboratory animals provide the opportunity to explore potential predictors that are difficult to investigate in human patients. Therefore we also describe results (from our lab and others) with RDN in spontaneously hypertensive rats. Since virtually all patients receiving RDN are taking three or more antihypertensive drugs, a particular focus of our work was on how ongoing antihypertensive drug treatment might alter the BP response to RDN. We conclude that patient age (or duration of hypertension) and concomitant treatment with certain drugs can affect the blood pressure response to RDN and that this information could help predict a favorable clinical response.