DEFINITION AND FREQUENCY: Hypertension may be termed refractory, when a therapeutic plan that has included nonpharmacologic treatment and the prescription of a triple drug combination in adequate doses including a diuretic, has failed to lower the blood pressure < 140/90 mmHg. True resistance can only be found in 2-5% of all hypertensive patients.CAUSES AND DIAGNOSIS:Pseudoresistance to antihypertensive therapy is common and often due to a suboptimal drug regime, interactions with other drugs or a secondary form of hypertension. It is estimated that in more than two thirds of patients with hypertension, poor compliance is at least part of the problem. Poor compliance is not easily detected by the physicians, and studies showed that they could not predict compliance with any more accuracy than if they were guessing. Factors for a poor compliance are lack of patient information about hypertension and its treatment, side effects of prescribed drugs, lack of teaching in the self-measurement of blood pressure and patient's dissatisfaction with the disease. Improvement of compliance can be achieved by selecting long-acting drugs or drug combinations. Structured teaching programs, as they become part of the Disease Management Programs (DMPs) in Germany can improve compliance as well.THERAPY:If noncompliance can be excluded, the dosage of antihypertensive drugs should be increased to a maximum if tolerated, or combinations of four or more drugs can be used, including drugs like minoxidil.

Therapierefraktärer Bluthochdruck liegt vor, wenn trotz Einsatz von drei pharmakologisch differenten Antihypertensiva in maximaler Dosierung der Druck bei Ausgangswerten von > 180/115 mmHg nicht < 160/100 mmHg und bei Ausgangswerten von < 180/115 mmHg nicht < 140/90 mmHg zu senken ist. Die Dreierkombination sollte ein Diuretikum, eine sympathikushemmende Substanz und einen Vasodilatator enthalten. Bei etwa 2–5% aller Hochdruckpatienten kann von einer therapierefraktären Form ausgegangen werden.

HISTORY:A 72-year-old male in acute renal failure, intubated and ventilated, was transferred to our hospital. He had a 30-years history of severe hypertension and signs of general atherosclerosis. 25 years ago, the left kidney had been removed because of an ischaemic renal infarction due to a renal artery stenosis. Blood pressure-monitoring showed excessive high systolic (up to 250 mmHg) and diastolic (up to 160 mmHg) blood pressure. INVESTIGATIONS:The MRI-scan revealed a single right kidney with a main artery and an accessory one, both with a severe ostial stenosis. The resistance index (RI) value, measured by duplex ultrasonography was 44. DIAGNOSIS AND TREATMENT:In two interventional procedures both stenosed arteries were dilated a stent was applied. Afterwards blood pressure and renal function improved. CONCLUSIONS:Severe hypertension can be caused by a renal artery stenosis. It can be diagnosed by duplex ultrasonographic studies, which has the advantage of determining the RI and therefore identifying patients with no improvement of blood pressure or renal function after resolving the stenosis. The angioplasty with or without a stent is as successful as an operation but has less complications.

Drug Prescribing for Patients with Chronic Kidney Disease in General Practice: a Cross-Sectional Study

History: A 72-year-old male in acute renal failure, intubated and ventilated, was transferred to our hospital. He had a 30-years history of severe hypertension and signs of general atherosclerosis. 25 years ago, the left kidney had been removed because of an ischaemic renal infarction due to a renal artery stenosis. Blood pressure-monitoring showed excessive high systolic (up to 250mmHg) and diastolic (up to 160mmHg) blood pressure.Investigations: The MRI-scan revealed a single right kidney with a main artery and an accessory one, both with a severe ostial stenosis. The resistance index (RI) value, measured by duplex ultrasonography was 44.Diagnosis and treatment: In two interventional procedures both stenosed arteries were dilated a stent was applied. Afterwards blood pressure and renal function improved.Conclusions: Severe hypertension can be caused by a renal artery stenosis. It can be diagnosed by duplex ultrasonographic studies, which has the advantage of determining the RI and therefore identifying patients with no improvement of blood pressure or renal function after resolving the stenosis. The angioplasty with or without a stent is as successful as an operation but has less complications.