Time to push back

The four-profile framework is elegant. It makes intuitive sense, it uses tools already in most clinics, and it offers a way to personalise treatment for a disease that is often handled with one approach for everyone.

That is exactly why it needs a hard look. Attractive ideas get adopted faster than they get tested. Here is what this paper does not show, and some of it the authors admit themselves.

It is a review, not a trial

This is a narrative review. It draws together existing studies and expert reasoning into an argument. It does not present a new trial testing whether phenotype-guided treatment beats standard treatment.

That distinction matters a lot. The core claim, that sorting outpatients into warm, cold, wet and dry by echo and blood test and then adjusting treatment accordingly will improve outcomes, has not been tested head to head in a randomised trial. The paper does not claim it has. But the confident tone of the proposal can make it feel more established than it is.

The closest thing to direct evidence is GUIDE-HF, which used an implanted pressure sensor, not echo. That is a meaningful difference. A sensor measures pressure continuously and directly. An echo estimates it at a single visit.

The group is citing itself

The key supporting data for the phenotype approach in outpatients, including the 727-patient sacubitril/valsartan cohort from Part 6, comes from studies run by the same study group that wrote this review. Several of the authors appear on those studies.

That is not unusual and it is not misconduct. Researchers naturally review the field they work in. But it does mean the evidence and the argument are coming from the same place. Independent replication from other groups would make the case much stronger.

Those supporting studies are also observational. The patients who ended up warm and dry and did well on sacubitril/valsartan may have done well partly because they were less sick to begin with. Sicker patients tolerate drugs worse. Observational data cannot fully separate "this profile responds better" from "healthier people are both in this profile and do better anyway".

The guidelines do not endorse this

The authors are upfront about this in their conclusion. Current heart failure guidelines suggest starting all four pillar drugs regardless of underlying mechanism, and no specific recommendations exist about tailoring therapy by echo and natriuretic peptide phenotype.

So what this paper proposes is a departure from guidelines, not an application of them. That does not make it wrong. Guidelines lag behind good ideas. But anyone reading it should know that following its approach means stepping outside current standard practice.

The measurements are harder than they look

The limitations section is candid about the practical problems:

  • Non-invasive cardiac output is not always easy to measure reliably, because of imprecision and differences between observers.
  • Choosing the right cut-off values is difficult. The VTI under 15 cm and stroke volume index under 30 ml/m² are proposals from some authors, not settled standards.
  • Other markers matter too, including right ventricular function, pulmonary hypertension and strain imaging, and they are not part of this four-box scheme.

And then this, which I think is the most honest line in the paper: "despite several attempts that have been made, no single algorithm of patients' phenotyping appears completely satisfactory."

The authors explain why: heart failure is the sum of many anatomical, functional and clinical behaviours. Four boxes are a simplification of that, just as ejection fraction was. It may be a better simplification, but it is still one.

Remember from Part 2 that one of the complaints about ejection fraction was variability between observers. E/e′ and VTI measurements have that problem too.

The risk of doing too little

Here is the concern I would weigh most heavily.

The four pillar drugs for heart failure with reduced ejection fraction are, in the paper's own words, life saving. One of the practical problems in heart failure care worldwide is that patients are under-treated: not started on all four drugs, or left on low doses.

A framework that tells clinicians to reduce or avoid beta-blockers and vasodilators in some patients could, in the wrong hands, become a reason to under-treat people who would actually tolerate and benefit from full therapy. The paper's recommendations for cold profiles, reduce or avoid certain drugs, are reasoned but not proven. And cold profile patients are, as the paper notes, often excluded from trials. So the recommendations for them rest on physiology and clinical judgement rather than trial data.

That can be the right call in genuinely unstable, low output patients. The risk is it drifts into more stable patients who just seem a bit fragile.

The steelman

To be fair to the authors, here is the strongest version of their case. The Forrester profiles predicted survival in the original research. Echo and peptide measurements do track outcomes in many studies. GUIDE-HF shows pressure-guided treatment reduces events. The physiology of why low output patients struggle with vasodilators is sound. And "treat everyone the same" is clearly imperfect.

All true. The gap is between "this is a sensible way to think about patients" and "this way of choosing treatment has been proven to make people live longer". The first is well supported. The second is not tested yet.

The takeaway

Use this framework as a lens, not a rulebook. It is a good way to understand why two people with the same diagnosis can respond so differently to the same drugs. It is not yet a validated way to decide who should get less of a life-saving treatment.

If any of your heart failure medications are reduced or stopped because of your profile, it is completely fair to ask: "Is this based on my current measurements, and when will we reassess whether I can go back up?"

This series discusses a peer-reviewed clinical review. Nothing here is medical advice. Heart failure treatment should always be guided by your own cardiology team.