Nesiritide in Hypertension

Inclusion Criteria: * Office systolic blood pressure (SBP) ≥ 120 mmHg and treatment with at least one anti-hypertensive medication. Unchanged medication regimen the last two weeks prior to inclusion. * Average day-time SBP \> 115 on a 24-h ambulatory BP measurement at screening. Exclusion Criteria: * Congestive Heart Failure (any New York Heart Association class) * Ejection Fraction ≤ 40 % * Known, not appropriately treated, secondary hypertension * Myocardial infarction within 3 months of screening * Unstable angina within 14 days of screening, or any evidence of myocardial ischemia * Pulmonary hypertension * Aortic stenosis with maximum jet velocity \> 2,5 m/s * Other valvular stenosis, hypertrophic, restrictive or obstructive cardiomyopathy, constrictive pericarditis or biopsy proven active myocarditis * Sustained Ventricular Tachycardia or Ventricular Fibrillation within 14 days of screening * Sustained Atrial Fibrillation * Second or third degree atrioventricular block without a permanent cardiac pacemaker * Cerebrovascular event within 3 months of screening, or other evidence of significantly compromised cerebral perfusion * Proteinuria defined as albumin:creatinine ratio \> 100 (equivalent to an excretion of \> 1 g/day) * Nephrotic syndrome * Body Mass Index \> 35 * Total bilirubin of \> 25 µmol/L, aspartate aminotransferase or alanine aminotransferase 1.5 times the upper limit of normal range * Renal insufficiency assessed by estimated glomerular filtration rate (GFR) \< 30 ml/min * Serum sodium of ≤ 135 mmol/L and ≥ 150 mmol/L * Serum potassium of ≤ 3.5 mmol/L and ≥ 5.5 mmol/L * Women taking hormonal contraceptives containing estrogens * Pregnancy * Patients on prolonged, i.e. more than 30 days, immunosuppressant therapy * Patients with known, active malignancies * Patients with orthostatic hypotension * Participation in a trial with an investigational product within the previous three months * Any contraindication listed on the Investigator's Brochure of the Investigational Medicinal Product * Any reason why, in the opinion of the investigator, the patient should not participate.