Diagnosis and Treatment of Resistant Hypertension: The Critical Role of Ambulatory Blood Pressure Monitoring

Abstract

Hypertension is an illness that generally requires lifelong treatment with blood pressure (BP)-lowering drugs. It is, therefore, understandable that increasing attention is being paid to interventional procedures that might provide a "cure" for hypertension and obviate the need for costly therapy that is not always without unwanted effects. Such interventional techniques are confined, for the moment, to patients with drug-resistant hypertension, ie, BP levels above a specified target despite adherence to at least 3 optimally dosed antihypertensive medications of different classes, including a diuretic, 1,2 to which we would add for a minimum of 3 months on such maximal treatment.In clinical research involving these procedures (as for research involving pharmaceutical therapies), two key aspects of a given trial's design merit particular attention: verification that individuals enrolled in the trial truly have drug-resistant hypertension and that there is no underlying cause for hypertension (ie, secondary hypertension); and the choice of BP endpoints to be assessed at specified timepoints following surgical interventions. There are now various measurement methodologies available to us with which to obtain BP data in both contexts, ie, as inclusion/exclusion criteria for entry into the trial and as measures of the intervention's efficacy. A question we must ask in both settings is: What is the most informative way we can assess BP? We believe the answers are uniform and clear: ambulatory BP monitoring (ABPM) is the most appropriate and informative methodology and should be mandatory in all studies to investigate interventional efficacy. TWO BP MEASUREMENT METHODOLOGIESConventional clinical BP measurement (CBPM) in a physician's office or at an investigational site during pharmacologic trials traditionally utilized the auscultatory technique that is more than 100 years old, although, recently, trials have used automated devices to measure BP. 3 While we believe that the auscultatory technique is inherently accurate, "it is dependent on observer attention to detail, which is often lacking, and it provides only a momentary measurement of BP, usually under circumstances that can influence the level of BP being measured."4 Moreover, even though automated techniques may improve accuracy, 5 the BP-measuring process is seriously flawed by providing only a snapshot of BP under circumstances that may elevate BP. For example, the phenomenon of white-coat hypertension, 6 in which an individual demonstrates higher BP levels in a physician's office or clinic than in other settings, is problematic when using CBPM (as is masked hypertension, the phenomenon of appearing normotensive in the office but having hypertension in other settings). 7Two arguments can reasonably be postulated. First, if participants in a clinical trial of a procedural intervention have been enrolled based on CBPM values that were indeed influenced by the white-coat phenomenon and then undergo the intervention, their true (lower) BP values are less likely t...

Renal Denervation in Patients With Uncontrolled Hypertension and Confirmed Adherence to Antihypertensive Medications

“…Because hypertension is generally an asymptomatic condition that requires lifelong treatment with medication, interest has grown in recent years in interventional and device‐based procedures as alternative treatments . The most researched of such techniques has been catheter‐based renal denervation (RDN), an invasive procedure that involves radiofrequency ablation of the sympathetic nerves surrounding the renal arteries .…”

Ambulatory Blood Pressure Monitoring in the Diagnosis, Prognosis, and Management of Resistant Hypertension: Still a Matter of our Resistance?

“…A subsequent position statement of the American Heart Association (AHA) considered patients whose BP is controlled by ≥4 antihypertensive medications to be also resistant to treatment (controlled resistant hypertension) [11]. More recently, it has been suggested that a time frame of at least 3 months of effective treatment should be included in the definition of resistant hypertension [24,25]. Although resistant hypertension by definition is considered not controlled, it should not be used identically with the term Buncontrolled hypertension^which refers to all hypertensive patients without adequate BP control under treatment [12••].…”

American Society of Hypertension Scientific Statements Addressing Resistant Hypertension

“…Second, it is important to determine more rigorously whether RDN is efficacious alone, and, if so, whether it is helpful as an adjunctive therapy for patients receiving antihypertensive medications. Third, ABPM is an important methodology . Fourth, assessment of long‐term safety is required.…”