Primary Aldosteronism Found During a Resistant-Hypertension Workup: Adrenal Vein Sampling or Empiric Spironolactone
A resistant-hypertension workup turned up biochemically confirmed primary aldosteronism and an adrenal nodule that imaging alone can't confirm is the actual source. The disagreement is about whether to find out for certain before treating, or to treat now regardless.
E.C., a 52-year-old man, had gone the better part of a decade avoiding anything resembling a real checkup, a habit his son — partway through nursing school and increasingly unwilling to let it slide — finally broke by sitting with him through an actual home blood-pressure log for two weeks straight. The numbers averaged 152 over 94, on a regimen that already includes three separate medications, a combination most guidelines would call resistant hypertension rather than simply undertreated.
The workup his primary doctor ordered for resistant hypertension found something more specific than "his blood pressure is hard to control." His aldosterone-to-renin ratio came back elevated — more convincingly so because both his lisinopril and his chlorthalidone push renin up and bias that test toward false negatives, so a positive result on those agents is harder to explain away — and a saline suppression test — infusing saline and checking whether aldosterone production suppresses the way it should in a normal adrenal gland — confirmed it: his adrenal glands are producing aldosterone independent of the renin-angiotensin system that's supposed to regulate it, a state that itself raises blood pressure and, incidentally, explained the mildly low potassium his last routine labs had shown without anyone connecting the two. A CT scan found a 1.2-centimeter nodule on his left adrenal gland, the kind of finding that invites an obvious-seeming next question — is that the source? — that CT imaging alone cannot actually answer. Small, hormonally silent adrenal nodules are common enough in the general population that an imaging-visible nodule and the true source of excess aldosterone frequently turn out to be different things; roughly a third of the time, imaging and the actual functional source disagree.
The test that can answer it directly — adrenal vein sampling, comparing hormone levels drawn from each adrenal vein separately to determine whether one side or both are truly overactive — is technically demanding, not universally available, and invasive in a way that "just start a medication instead" is not. Whether he needs that answer before treatment starts, or whether treatment can reasonably start regardless of which answer it would give, is the actual question in front of him.
Reviewing a confirmed diagnosis with an unconfirmed source
I'd pursue adrenal vein sampling before deciding anything further. If the source is truly unilateral — a genuine aldosterone-producing adenoma — adrenalectomy offers a realistic chance of cure or major medication reduction, a categorically different outcome than lifelong medical therapy. He's 52, with a long expected span of blood-pressure management ahead of him; it's worth pursuing the test that could change his entire treatment trajectory rather than assuming medical therapy by default.
Practically speaking, adrenal vein sampling is only performed reliably at a handful of specialized centers, isn't available anywhere near where he lives without significant travel and cost, and carries real procedural risk and interpretive uncertainty even at expert centers. Spironolactone, a direct mineralocorticoid receptor antagonist, treats primary aldosteronism effectively regardless of whether the source is unilateral or bilateral, and could realistically bring his blood pressure under control within weeks. I'd start effective treatment now rather than delay it for a test he may not be able to access — accepting, and saying out loud, that this is a fork rather than a parallel track.
On the medication itself — spironolactone is the most effective mineralocorticoid receptor antagonist for aldosteronism, but it carries a real antiandrogenic side-effect profile, gynecomastia and decreased libido in particular, that matters for a 52-year-old man and is a common reason people stop taking it. Eplerenone, a more selective mineralocorticoid receptor antagonist, avoids most of that burden at the cost of somewhat less potency and twice-daily dosing. I'd start with spironolactone given its stronger track record, and switch to eplerenone specifically if antiandrogenic effects become a problem. Two sequencing points before anyone writes the prescription. First, these two plans cannot simply run alongside each other: mineralocorticoid receptor antagonists have to be withdrawn for four to six weeks before adrenal vein sampling, because by unblocking the receptor they raise renin, and unsuppressed renin drives aldosterone out of the healthy gland too and flattens the very difference the test is measuring. Starting spironolactone today and sampling next month yields a study nobody can interpret. So it is either sample first — controlling his pressure meanwhile with agents that don't stimulate renin, verapamil or doxazosin or hydralazine — or start spironolactone now and build the washout into the plan if he later decides he wants the answer. Second, he is on lisinopril, and adding a mineralocorticoid receptor antagonist on top of an ACE inhibitor is the classic hyperkalemia setup; his potassium of 3.3 gives him room, but it needs potassium and creatinine checked at one week and again at four, not assumed. Whether he pursues sampling versus empiric therapy is genuinely his tradeoff to make — a possible cure weighed against real logistical and financial barriers — not something either specialist should settle for him.
Agreed: start spironolactone today rather than waiting, continue his existing regimen otherwise, check potassium and creatinine at one and four weeks, and place the adrenal-vein-sampling referral now with the sequencing stated explicitly — that a four-to-six-week spironolactone washout, covered by renin-neutral agents, has to precede the study for it to be interpretable.
Not agreed, and the reason his own follow-through, not just the test result, was named directly as part of the uncertainty:
Refer for adrenalectomy as a realistic path to reduced or discontinued medication.
Continue and optimize medical therapy indefinitely, with spironolactone as the anchor drug.