Prof. Athanasios J. Manolis,
View the Slides from this session in ESC Congress 365
Resistant hypertension (RHTN) is defined as resistance to treatment, i.e. when a therapeutic strategy that includes appropriate lifestyle measures plus a diuretic and two other antihypertensive drugs of different classes at adequate doses fail to lower SBP and DBP values below 140 and 90 mmHg, respectively. It is of great importance for clinicians not to confuse RHTN with uncontrolled hypertension. The latter includes patients with poorly treated BP due to inadequate medical therapy, inappropriate lifestyle habits or poor adherence to medication; however a subcategory suffers from true RHTN. The prevalence of RHTN among hypertensives has been extensively debated, and conflicting data have been presented, ranging from 10%, up to 50% in nephrology clinics. In subgroup analyses of large clinical trials, its prevalence may be up to 38%, however all the trials were not designed to identify RHTN and further large-scale observational studies will be needed to better elucidate its magnitude. Although no studies have addressed prognosis, it could be assumed that patients with RH are at high cardiovascular risk.
Before starting any drug treatment, clinicians should exclude pseudoresistant hypertension, which results from non-adherence to medications or from white coat hypertension, other related causes, and secondary forms of hypertension. The next step will be a combination of life style changes and medical treatment. Physicians should prescribe drugs with long duration of action and high trough-to-peak ratio because not only will this improve the blood pressure control, but also the adherence of the patient. Treatment should include two drugs plus a diuretic, and according to the current ESH/ESC guidelines this will be a combination of a RAS blocker with a calcium channel blocker and a diuretic unless there are specific conditions. The role of the diuretic is crucial. In patients with RHTN, volume overload due to salt and water retention is the most common mechanism leading to increased blood pressure. So, it is important for any antihypertensive treatment to be accompanied by salt restriction. In addition, antihypertensive drugs are more effective when patients are under salt restriction. However, if blood pressure control improvement in compliant patients is the therapeutic target, at least two other classes of antihypertensive drugs are available in our armamentarium: beta-blockers (the ones with vasodilatory effects such as nebivolol and carvedilol seem preferable) and aldosterone antagonists.
In patients with RHTN, despite receiving triple drug treatment including a diuretic in adequate dose, carotid baroreceptor stimulation or renal denervation can be considered. Chronic electrical stimulation of carotid sinus nerves via implantable devices has shown significant reduction in both systolic and diastolic blood pressure. However, longer-term observations have involved only a restricted number of patients and further data on larger numbers of patients are needed to confirm the efficacy and safety of the method. One of its main limitations is the surgical procedure, the need for general anesthesia, and the size of the device. In renal denervation, a wide range in the blood pressure lowering effect has been reported. The Symplicity HTN-1 and 2 trial showed a significant reduction of systolic and diastolic BP after the procedure however, the results of the Symplicity HTN-3 trial were disappointing.
Resistant hypertension represents a real challenge in the treatment of hypertensive patients in every day clinical practice. However, clinicians have to distinguish first the cases of uncontrolled or pseudoresistant hypertension in order to improve treatment and subsequent prognosis of those patients.
What cardiologists need to know about resistant hypertension
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