Renal sympathetic denervation after Symplicity HTN-3 and therapeutic drug monitoring in severe hypertension

Nanosensors in the detection of antihypertension drugs, a golden step for medication adherence monitoring

Hypertension is associated with structural and functional changes in blood vessels with increased arteriosclerosis, vascular inflammation, and endothelial dysfunction. Decreased adherence (compliance) to antihypertensive medications contributes significantly to morbidity and mortality in hypertensive patients. Antihypertensive drugs (AHTDs) and lifestyle changes are the main cornerstones for treating hypertension. Several approaches have been described in the literature for determining AHTDs based on different analytical techniques. Amongst biosensors are one of the most attractive tools due to their inherent advantages. Biosensors are used for the detection of wide range of biomarkers as well as different drugs in past two decades. The main focus of the present study is to review the latest biosensors developed for the detection of AHTDs. Readers of the present study will be able to familiarize themselves with biosensors as advanced and modern diagnostic tools while reviewing the most widely used AHTDs. In the present study, the routine methods are first reviewed and while examining their advantages and disadvantages, biosensors have been introduced as ideal alternative tools.

Detection of Nonadherence to Antihypertensive Treatment by Measurements of Serum Drug Concentrations

[Figure: see text].

Blood pressure response to renal denervation is correlated with baseline blood pressure variability: a patient-level meta-analysis

BACKGROUND

Sympathetic tone is one of the main determinants of blood pressure (BP) variability and treatment-resistant hypertension. The aim of our study was to assess changes in BP variability after renal denervation (RDN). In addition, on an exploratory basis, we investigated whether baseline BP variability predicted the BP changes after RDN.

METHODS

We analyzed 24-h BP recordings obtained at baseline and 6 months after RDN in 167 treatment-resistant hypertension patients (40% women; age, 56.7 years; mean 24-h BP, 152/90 mmHg) recruited at 11 expert centers. BP variability was assessed by weighted SD [SD over time weighted for the time interval between consecutive readings (SDiw)], average real variability (ARV), coefficient of variation, and variability independent of the mean (VIM).

RESULTS

Mean office and 24-h BP fell by 15.4/6.6 and 5.5/3.7 mmHg, respectively (P < 0.001). In multivariable-adjusted analyses, systolic/diastolic SDiw and VIM for 24-h SBP/DBP decreased by 1.18/0.63 mmHg (P ≤ 0.01) and 0.86/0.42 mmHg (P ≤ 0.05), respectively, whereas no significant changes in ARV or coefficient of variation occurred. Furthermore, baseline SDiw (P = 0.0006), ARV (P = 0.01), and VIM (P = 0.04) predicted the decrease in 24-h DBP but not 24-h SBP after RDN.

CONCLUSION

RDN was associated with a decrease in BP variability independent of the BP level, suggesting that responders may derive benefits from the reduction in BP variability as well. Furthermore, baseline DBP variability estimates significantly correlated with mean DBP decrease after RDN. If confirmed in younger patients with less arterial damage, in the absence of the confounding effect of drugs and drug adherence, baseline BP variability may prove a good predictor of BP response to RDN.

[Physician knowledge and attitudes on the clinical evaluation and treatment of resistant hypertension: The RESIST study]

BACKGROUND

Resistant hypertension (RH) is associated with a high risk of cardiovascular and renal complications. The purpose of this study was to assess the knowledge and attitudes of Primary Care physicians, general medicine doctors, and clinical cardiologists on the management of this condition.

MATERIAL AND METHODS

A multicentre, descriptive, observational study based on an ad hoc questionnaire distributed to Primary Care physicians (n=1017) and general medicine physicians/clinical cardiologists (n=457).

RESULTS

To establish the diagnosis of resistant hypertension, 69.1% of physicians confirm that systolic/diastolic blood pressure is above 140/90 mmHg, despite treatment. Furthermore, 64.9% only consider this diagnosis if the patient is treated with at least 3 medications, and 50.3% also requires that one of them is a thiazide diuretic (56.7% among specialists, P=.0004). To establish a definite diagnosis of true RH, 89.6% perform 24-h ambulatory blood pressure monitoring (93.3% of specialists, P=.0017), looking specifically for «white-coat» effect in 70.2% of cases. In addition, 79.3% verify that adherence to treatment is adequate. Between 87 and 95% of physicians indicate examinations to exclude causes of secondary hypertension. Up to 54.3% of physicians (71.3% specialists, P<.0001) consider adding a fourth drug and insisting on lifestyle interventions as a priority therapeutic measure.

CONCLUSION

These data show that physician knowledge regarding the management of patients with RH is good. Interestingly, this knowledge is somewhat higher among specialists than among Primary Care physicians.

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.

Renal sympathetic denervation in treating drug-resistant hypertension in a patient on hemodialysis

A 26-year-old man had an end-stage renal disease because of a neurogenic urinary bladder with a vesicourinary reflux. The first kidney transplant was lost in consequence of chronic allograft nephropathy. Immunosuppressive medication was withdrawn and transplantectomy was performed in November 2010. After transplantectomy, his blood pressure (BP) slowly increased up to 200/100 mmHg. Antihypertensive medication was intensified and a fluid overload was excluded with body composition bioimpedance measurements. Forty-eight-hour ambulatory BP was 180/109 mmHg in the daytime and 178/108 mmHg in the night-time. Bilateral renal denervation (RDN) was performed with a single electrode Symplicity catheter on May 2013. The effect of RDN became evident at the 6 months visit, and all the antihypertensive medicines were withdrawn at 12 months. Fifteen months after RDN, 48-h ambulatory BP was 120/63 mmHg in the daytime and 108/60 mmHg in the night-time. The patient was without antihypertensive medication until retransplantation in May 2015.

Adherence to medication and drug monitoring in apparent treatment-resistant hypertension

Poor drug adherence is one of the main reasons for the failure to achieve treatment targets in hypertensive patients. In patients who receive pharmacological treatment, assessment of drug adherence is of the utmost importance. The aim of this review is to present an update of the methods available to reveal and monitor non-adherence in patients with apparent treatment-resistant hypertension. Methods for monitoring adherence are divided into indirect and direct methods. The indirect methods are mainly based on self-reported adherence and can easily be manipulated by the patient. Directly observed therapy and therapeutic drug monitoring are examples of direct methods. There are limitations and advantages to all of the methods, and because of the patient's ability to manipulate the outcome of indirect methods, direct methods should be preferred. Therapeutic drug monitoring and directly observed therapy with subsequent ambulatory blood pressure measurement are considered to be reliable methods and should be used more in the routine assessment of patients with apparent treatment-resistant hypertension.