This will be a single-center, randomized, open-label, parallel-group study in patients with treatment-naive arterial hypertension to characterize RAS peptide profiles before and after treatment initiation with different antihypertensive drug-classes. Patients diagnosed with primary arterial hypertension requiring antihypertensive drug treatment as well as patients after a 4 week wash out period (Amendment from 07/2016) will be recruited from the Medical Outpatient Clinic at the University Hospital Basel, Switzerland. Diagnostic work-up and follow-up assessments after treatment initiation such as 24 hour blood pressure measurement will be performed according to clinical practice guidelines and will only be documented but not altered by this study. Study mandated procedures will be randomization to one of the four standard first-line treatment arms, blood sampling for RAS peptide profile and drug concentration determination, and non-invasive hemodynamic measurements. After having provided written informed consent, patients will be randomized to either the angiotensin-converting enzyme inhibitor-, angiotensin receptor blocker-, calcium channel blocker- or hydrochlorothiazide-treatment arm. Drug treatment follows current guidelines issued by the European Society of Hypertension . According to clinical practice, treatment-naive patients with grade I and grade II hypertension will directly be started on an intermediate dose monotherapy (treatment period 1).~Treatment period 1:~4 weeks of intermediate dose monotherapy with the angiotensin-converting enzyme Inhibitor perindopril OR the angiotensin receptor blocker olmesartan OR the calcium channel blocker amlodipine OR the hydrochlorothiazide~In all patients who do not reach blood pressure targets according to the 2013 ESH guidelines for the management of arterial hypertension after 4 weeks, the dose of the monotherapy drug will be doubled (high dose, treatment period 2), following current guidelines~Treatment period 2:~4 weeks of high dose monotherapy with the angiotensin-converting enzyme inhibitor perindopril OR the angiotensin receptor blocker olmesartan OR the calcium channel blocker amlodipine OR the hydrochlorothiazide~80 patients (20 patients per treatment arm) will be included and sampling for the analysis of RAS peptide profiles will be done before treatment initiation (baseline). Sampling for the analysis of RAS peptide profiles and measurement of drug concentrations in plasma will be done after 4 weeks of each treatment period at 0h (before last drug intake) and 4 hours after last drug intake of treatment period. Dropouts will be replaced. Non-invasive hemodynamic measurements will be done at the same time points as for the determination of RAS peptide profiles and drug concentrations.~A control group with 20 age- and gender-matched, healthy and normotensive subjects will be recruited to establish the characteristics of RAS peptide profiles in a comparable but normotensive population. After having provided written informed consent, normal blood pressure will be documented by a 24h blood pressure measurement. In this normotensive control group, blood sampling for the determination of RAS peptide profiles as well as hemodynamic measurements will only be done on a single day, at the same time of day as for the hypertensive patients. (Amendment 04/2015)
Randomized, open-label, parallel-group study conducted at a single center in Switzerland.~Patients diagnosed with primary arterial hypertension requiring antihypertensive drug Treatment as well as patients after a 4 week wash out period (Amendment 07/2016) will be recruited at the University Hospital Basel, Switzerland. Subjects will be randomized to either the angiotensin-converting enzyme inhibitor-, angiotensin receptor blocker-, calcium channel blocker- or hydrochlorothiazide-treatment arm. Drug treatment follows current guidelines issued by the European Society of Hypertension. Treatment-naive patients will be started on an intermediate dose monotherapy (treatment period 1). In all patients who do not reach blood pressure targets after 4 weeks, the dose of the monotherapy drug will be doubled (high dose, treatment period 2). Sampling for the analysis of RAS peptide profiles, measurement of drug concentrations in plasma and non-invasive hemodynamic measurements will be done. A control group with 20 age and gender matched, healthy and normotensive subjects will be recruited to establish the characteristics of the RAS peptide profiles in a comparable but normotensive population.