Detection of secondary hypertension in refractory hypertension without clinical or biological signs an aetiology.

The aim of this study was to determine the prevalence of secondary hyperten sion in a population of refractory hypertension without initial clinical or biological findings suggesting identifiable causes of hypertension. Methods: A survey included 200 consecutive hypertensive patients referred t o hypertension specialists for refractory hypertension (BP> 140/90 mmHg on at least two antihypertensive drugs). Prior inclusion, the permanent elevat ion of blood pressure was confirmed by ambulatory monitoring. In each subje ct an extensive workup was performed to detect a secondary cause for hypert ension. Results: An essential hypertension was confirmed in 61% of this cohort. A s econdary hypertension was detected in 20% of the patients; 8.5% with a prim ary hyperaldosteronism, 8% with a reno-vascular hypertension and 3% with a nephropathy. Moreover, 18.5% had a low renin hypertension. Thus, 27% of the se patients had an abnormality of the renin-aldosterone axis. Conclusion: Patients with refractory hypertension should be explored to det ect secondary hypertension even without findings suggesting such causes. Th is additional diagnostic procedure must include at least renovascular inves tigations and plasma renin/aldosterone level determinations in appropriate conditions.