The Worship of Gadgets and Gadget Procedures

“Gizmo Idolatry”

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Franz H. Messerli, MD, an internationally recognized hypertension expert, has just written an interesting Viewpoint in JACC entitled “Renal Denervation – Antihypertensive Therapy or Gizmo Idolatry?” (1). “Gizmos Idolatry” was defined in 2008 by Leff and Finucane as the “willingness to accept, in fact to prefer, unproven, technologically oriented medical measures.”(2) The target of Messerli’s editorial is “renal denervation therapy” (RDN). Two devices to perform this procedure were approved by an FDA advisory committee on August 23, 2023.

RDN involves placing a catheter into the renal artery and denervating the nerves surrounding the artery using ultrasound or radiofrequency-induced heat. The initial reductions in blood pressure after RDN are impressive, but Messerli points out that the decrease in systolic blood pressure (SDP) 2 months after the procedure is less than 5 mm Hg compared to the sham procedure, and that the reduction in SBP at 6 months is only 3 mm Hg. He notes that up to a third of patients don’t respond at all and that these patients cannot be identified in advance. Perhaps the most damning statement comes from Dr. Richard Lange, who was the chairman of the advisory committee that approved the devices, who said, “….I can’t honestly look patients in the eye and tell them that the benefit outweighs the risk for the population at large.”(1)

So why is there any enthusiasm at all for such a procedure? Well, the procedure was approved for medical-therapy-resistant hypertension or “refractory hypertension”, and even Messerli agrees that RDN is appropriate for truly medicine-resistant hypertension, but truly resistant hypertension is rare. And as Messerli points out, the primary mechanism producing resistant hypertension, besides medicine non-compliance, is fluid retention, often due to mineralacorticoid excess.

Hypertension from fluid retention is like watering tomatoes. If you need to water the tomatoes in the far corner of the garden, you need to provide sufficient water pressure. So, you can turn up the faucet to increase flow and thereby pressure, or you can put your thumb over the end of the hose. A smarter clinician would say something like, “Pressure equals flow times resistance,” but I’m only a cardiologist so prefer to “water the tomatoes.” Many of the drugs we use reduce resistance, so the body tries to expand plasma volume, which is akin to turning up the faucet. A diuretic often helps a lot to reduce pressure by reducing volume.

Why did Messerli specify “mineralocorticoid excess”? That’s because increased aldosterone levels are frequent in difficult-to-treat hypertension, not due to aldostronomas, but just excess adrenal activity.

Interestingly, Susan Oparil, MD, is one of the authors of the paper that Messerli cites to support the mineralacorticoid statement. Dr. Oparil was the first female cardiology fellow at the Massachusetts General Hospital, and I distinctly remember her telling me, years ago, that most resistant hypertension could be cured by spironolactone. She has been so right and many patients sent to me for refractory hypertension have benefited from that pearl.

It will be interesting to see how widely RDN is used. Once any device is approved, however, many clinicians rapidly forget the data and kneel before the gizmo. I personally have never been a fan of atrial appendage closure devices (AACD), which are now all the rage. AACDs are used to prevent systemic emboli in patients with atrial fibrillation. If you have atrial fibrillation, you cannot watch television without being convinced that anticoagulation is dangerous and you need something “better.” Clinicians forget that the studies comparing AACD with medical therapy used coumadin for comparison, and not the newer anticoagulants. Multiple studies have shown that patients on coumadin are in therapeutic range only about 70% of the time, meaning that 30% of patients on coumadin are at risk for bleeding or clotting. In contrast, the newer factor Xa inhibitors require little dose titration so that patients are fully anticoagulated within several hours if they just take the pill. Factor Xa inhibitors also have about half the cerebral bleeding than coumadin (4) probably because coumadin reduces clotting factor VII, also known as tissue factor, which is responsible for cerebral clotting. Without the factor VII clotting factor, patients are at risk for brain bleeds. I don’t fear most other bleeding as long as there is blood in the bank, but cerebral bleeds on coumadin are a real drag. Even against such a weak comparison as coumadin, the AACD were only “non-inferior” to coumadin.

So many of the procedures we do in cardiology are really no better than medical therapy, but we are bombarded by pressure to do stuff. Some of the pressure comes from salespeople, who overpromise the drug or device. Some of the pressure is peer-pressure. How can I only recommend medicines, when everyone else is “fixing it”? A lot of the pressure comes from patients who have become convinced that doing something means fixing the problem. And a lot of the pressure is internal to the clinician. If I recommend a procedure and it goes badly, the patient and family think I did everything I could. On the other hand, if I recommend a more conservative course and there is a problem everybody asks why I didn’t do something. And finally, there are financial considerations. Clinicians and hospitals make more money by doing procedures than by pushing pills and recommending good behavior.

Examples of our gizmo idolatry are endless. In cardiology, coronary angioplasty does not produce better outcomes than medical therapy for most patients with stable, severe inducible ischemia (as long as left main and proximal left anterior descending stenoses are excluded). (5) A therapeutic walking program is as good as a vascular intervention in most patients with symptomatic claudication. Medical therapy is as good as a carotid intervention in asymptomatic patients with carotid stenoses. (5)

I am not criticizing others. I am criticizing me. I belong to the gizmo culture for some of the reasons I mentioned above. Right now there is a lot of discussion about cutting Medicare and how insurance companies deny needed care. We need to make sure that patients know the truth about the gizmos we idolized, and we need to help them make informed decision based on randomized controlled clinical trials. But we can’t do this if patients are convinced we are denying them a cure if we restrict use of a gizmo.

If I headed Medicare or an insurance company, I would start an aggressive advertising campaign so that patients know the whole truth about some of these procedures we recommend. Patients and doctors making decisions based on good studies would save billions. It would not cost lives and it wouldn’t require anyone parading around with a chain saw.

1. Messerli FH. Renal Denervation: Antihypertensive Therapy or Gizmo Idolatry? J Am Coll Cardiol. 2025 Feb 18;85(6):649-651. PMID: 39818662

2. Leff B, Finucane TE. Gizmo idolatry. JAMA. 2008 Apr 16;299(15):1830-2. PMID: 18413879

3. Acelajado MC, Hughes ZH, Oparil S, Calhoun DA. Treatment of Resistant and Refractory Hypertension. Circ Res. 2019 Mar 29;124(7):1061-1070. PMID: 30920924

4. Ko D, Chung MK, Evans PT, Benjamin EJ, Helm RH. Atrial Fibrillation: A Review. JAMA. 2025 Jan 28;333(4):329-342. PMID: 39680399

5. Maron DJ, et.al. Initial Invasive or Conservative Strategy for Stable Coronary Disease. N Engl J Med. 2020 Apr 9;382(15):1395-1407. doi: 10.1056/NEJMoa1915922. Epub 2020 Mar 30.PMID: 32227755

6. Reiff T, et.al. Carotid endarterectomy or stenting or best medical treatment alone for moderate-to-severe asymptomatic carotid artery stenosis: 5-year results of a multicentre, randomised controlled trial. Lancet Neurol. 2022 Oct;21(10):877-888. PMID: 36115360

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