[What tests should be conducted for secondary arterial hypertension in hypertensive patients resistant to treatment?]

The aim of this study was to determine the prevalence of secondary hypertension in a population of refractory hypertension without initial clinical or biological findings suggesting identifiable causes of hypertension.

A survey included 200 consecutive hypertensive patients referred to hypertension specialists for refractory hypertension (BP > 140/90 mmHg on at least two antihypertensive drugs). Prior inclusion, the permanent elevation of blood pressure was confirmed by ambulatory monitoring. In each subject an extensive work-up was performed to detect a secondary cause for hypertension.

An essential hypertension was confirmed in 61% of this cohort. A secondary hypertension was detected in 20% of the patients; 8.5% with a primary hyperaldosteronism, 8% with a reno-vascular hypertension and 3% with a nephropathy. Moreover, 18.5% had a low renin hypertension. Thus, 27% of these patients had an abnormality of the renin-aldosterone axis.

Patients with refractory hypertension should be explored to detect secondary hypertension even without findings suggesting such causes. This additional diagnostic procedure must include at least renovascular investigations and plasma renin/aldosterone level determinations in appropriate conditions.