Revisiting malignant hypertension: rationale and design of the 'HAMA cohort', on behalf of the ESH working group 'hypertension and the kidney'.

BACKGROUND: Malignant hypertension has not disappeared and is associated with a poor prognosis. Yet, so far, it has received limited attention from the medical community. Guidelines are mainly based on expert consensus and low quality evidences. METHOD: We set up a prospective, multicenter, observational cohort of patients with malignant hypertension. We collect at admission medical history, demographic data, ongoing treatment, clinical parameters, symptoms, care pathways, target organ status and at discharge and during follow up treatment administrated, adverse events, blood pressure level, target organ status. We aim to recruit 500 patients with malignant hypertension in 5 years, with a 5-year follow-up. Our primary objective is to assess the 5 years prognosis of these patients. DISCUSSION: The HAMA (Hypertension Arterielle MAligne, meaning malignant hypertension) registry aims to describe the epidemiology and to assess the prognosis of malignant hypertension in a contemporary multidisciplinary cohort, with emphasis on the diversity of current management and care pathway among the different medical specialties. It may help improving our pathophysiological knowledge, and pave the way to update the definition of this particular form of hypertension. The multidisciplinary network developed in the wake of this project is expected to facilitate the set up therapeutic trials, laying the ground for evidence-based recommendations.

Estimation of intrathecal IgG synthesis: simulation of the risk of underestimation.

OBJECTIVE: The low level of passively diffused IgG through the blood-brain barrier is sufficient to blur the estimation of intrathecal IgG synthesis (ITS). Therefore, this estimation requires a mathematical calculation derived from empirical laws, but the range of normal values in healthy controls is wide enough to prevent a precise calculation. This study investigated the precision of various methods of ITS estimations and their application to two clinical situations: plasma exchange and immune suppression targeting ITS. METHODS: Based on a mathematical model of ITS, we constructed a population of healthy controls and applied a tunable ITS. RESULTS: We demonstrate the following results: underestimation of ITS is common at individual level but true ITS is well fitted by cohorts; Q IgG increases after plasma exchange; IgG Loc calculation based on Qlim falsely increases when Q Alb decreases; the sample size required to demonstrate a decrease in ITS increases exponentially with larger Q Alb. INTERPRETATION: Studies evaluating changes in ITS level should be adjusted to Q Alb. Low amounts of ITS could be largely underestimated.