Monday, March 11, 2019

Renin-aldosterone profiling for all hypertensives? Have we come full circle?

Decades ago John Laragh popularized renin profiling for the evaluation of hypertensive patients. But due to limited availability of testing in community practice and a shift in the way population based research was applied to the treatment of hypertension it fell out of favor. More recently interest has resurfaced. In a recent issue of JACC there is a paper on the prevalence and clinical characteristics of primary aldosteronism. From the paper:

Background Despite being widely recognized as the most common form of secondary hypertension, among the general hypertensive population the true prevalence of primary aldosteronism (PA) and its main subtypes, aldosterone-producing adenoma (APA) and bilateral adrenal hyperplasia (BAH), remains a matter of debate.

Objectives This study sought to determine the prevalence and clinical phenotype of PA in a large cohort of unselected patients with hypertension, consecutively referred to our hypertension unit, by 19 general practitioners from Torino, Italy.

Methods Following withdrawal from all interfering medications, patients were screened for PA using the ratio of serum aldosterone to plasma renin activity. PA was diagnosed according to Endocrine Society guidelines. The diagnosis was confirmed or excluded by an intravenous saline infusion test or captopril challenge test and subtype differentiation was performed by adrenal computed tomography scanning and adrenal vein sampling, using strict criteria to define successful cannulation and lateralization of aldosterone production.

Results A total of 1,672 primary care patients with hypertension (569 newly diagnosed and 1,103 patients already diagnosed with arterial hypertension) were included in the study. A total of 99 patients (5.9%) were diagnosed with PA and conclusive subtype differentiation by adrenal vein sampling was made in 91 patients (27 patients with an APA and 64 patients with BAH). The overall prevalence of PA increased with the severity of hypertension, from 3.9% in stage 1 hypertension to 11.8% in stage 3 hypertension. Patients with PA more frequently displayed target organ damage and cardiovascular events compared with those without PA, independent of confounding variables.

Conclusions Our results demonstrated that PA is a frequent cause of secondary hypertension, even in the general population of patients with hypertension, and indicates that most of these patients should be screened for PA.

An editorial in the same issue advocates for screening of all hypertensives.

There were some eye opening findings. Of the target organ complications cited above, LVH was seen in 54% of patients with PA vs 32% of those with essential hypertension (EH), microalbuminuria in 27% with PA vs 13% with EH and cardiovascular events in 15% with PA vs 6% with EH. Serum potassium was not a useful marker, as hypokalemia was seen in only 29% of those with PA.

Screening is not that difficult but what if the patient tests positive? That would lead to a lot of CT scans and invasive adrenal vein samplings. As the speaker in the audio file said, it’s something to think about the next time a patient with hypertension comes into your office.

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