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Cardiac cell therapy is the oldest sustained research programme in this field, running since the early 2000s, and it has produced more randomised trials than every other indication on this site combined. Stem cell therapy for ischaemic heart disease is therefore the best test available of what happens to a promising idea when it is properly studied for twenty years.
A field with real trials
A phase 3 randomised clinical trial has tested intracoronary infusion of cells to prevent heart failure after myocardial infarction — Prevention of acute myocardial infarction induced heart failure by intracoronary infusion of mesenchymal stem cells: phase 3 randomised clinical trial (PREVENT-TAHA8).
A large trial examined mesenchymal precursor cells in ischaemic heart failure — Mesenchymal precursor cells reduce mortality and major morbidity in ischaemic heart failure with inflammation: DREAM-HF.
An allogeneic cardiac cell programme was designed and published in detail — ALLogeneic Heart STem Cells to Achieve Myocardial Regeneration (ALLSTAR) Trial: Rationale and Design.
Phase 3. Mortality endpoints. Named, registered, published trials. This is a proper research field, which distinguishes it sharply from most of what is sold in medical tourism.
What twenty years of trials produced
The early studies in the 2000s reported improvements in ejection fraction — the proportion of blood the heart pumps out with each beat — that looked substantial.
As trials got larger, better blinded and more rigorously conducted, those effects shrank. That pattern is the normal history of a treatment effect that was partly artefact, and it is the single most useful thing to understand about this literature.
Some recent trials remain positive, particularly where they selected patients by inflammatory markers rather than treating everyone. That is a refinement of the question rather than a confirmation of the original claim.
Anyone citing a 2005 trial without mentioning what happened in the twenty years since is not describing the state of the evidence.
The mechanism changed along the way
The original rationale was regeneration: new cells becoming new heart muscle, replacing tissue killed by a heart attack.
That is no longer the proposed mechanism in serious research. Transplanted cells do not persist in the heart in meaningful numbers, and the current explanation is paracrine — signalling that reduces inflammation, affects blood vessel formation and influences remodelling.
Early work examined effects on coronary remodelling directly — Time-dependent effects on coronary remodeling and epicardial conductance after intracoronary injection of enriched hematopoietic bone marrow stem cells in patients with previous myocardial infarction — and the microcirculation was studied as a sub-study of an injection trial — Intracoronary stem-cell injection after myocardial infarction: microcirculation sub-study.
A clinic still describing this as rebuilding heart muscle is using the rationale the field abandoned. MSC immunomodulation covers where the mechanism thinking now sits.
How it is delivered in trials
Intracoronary infusion, through a catheter into the coronary arteries during a procedure in a cardiac catheterisation laboratory.
Direct injection into the heart muscle, either through a catheter with mapping, or during open cardiac surgery. A phase I trial studied a cell spray applied to the heart surface in ischaemic cardiomyopathy — Safety and therapeutic potential of allogeneic adipose-derived stem cell spray transplantation in ischemic cardiomyopathy: a phase I clinical trial.
These are cardiology and cardiac surgery procedures requiring a hospital, an interventional team and the ability to manage complications.
Peripheral intravenous infusion is what is typically sold in medical tourism, and it is not what the trials did. That difference is not a detail.
Why ejection fraction is a slippery endpoint
It is measured by imaging, it varies between operators and between imaging methods, and it changes with heart rate, blood pressure and fluid status on the day.
A few percentage points of measured change can reflect nothing more than measurement conditions, which is why early unblinded trials reporting improvements of that size were viewed cautiously by cardiologists at the time.
Hard endpoints — death, hospital admission for heart failure, further heart attack — cannot be measured into existence. Trials that report those are the ones worth attending to.
DREAM-HF is significant precisely because it reported on mortality and major morbidity rather than on an imaging number.
What established treatment already does
Modern heart failure treatment has transformed outcomes over the last decade, with four drug classes carrying large randomised evidence and substantial mortality reductions.
Revascularisation, device therapy, and cardiac rehabilitation all have strong evidence and are widely available, including in Thailand.
Anyone considering cell therapy should have been optimised on established treatment by a cardiologist first. The benefit there is demonstrated, large, and not in dispute.
Recovery after a heart attack covers the acute setting specifically.
Risks
Delivered properly, the procedural risks are those of cardiac catheterisation: bleeding, vessel injury, arrhythmia, and rarely a further heart attack or stroke.
Arrhythmia has been a specific concern with some cell types delivered into heart muscle, which is one reason trials monitor rhythm closely.
Infusion reactions and transient fever with intravenous delivery, as elsewhere in this field.
Delay in receiving effective established treatment is the risk that causes most harm in practice. Adverse events covers documented harms.
Questions worth asking
- Which trial does this protocol follow, and how is it delivered?
- Is this intracoronary or intramyocardial, or is it a peripheral infusion?
- Who performs it, in what facility, with what capacity to manage a complication?
- Has my medical therapy been optimised by a cardiologist?
- What endpoint would tell us whether it worked?
What the evidence levels mean explains the grading, and the patient journey covers what assessment involves.
Frequently asked questions
Is there real evidence in heart disease?
Yes — more randomised trials than any other indication on this site, including phase 3 work with mortality endpoints. The effects are modest and contested.
Can cells rebuild heart muscle?
That was the original rationale and serious research has moved away from it. Transplanted cells do not persist in the heart in meaningful numbers.
Why did early results look better?
As trials became larger and better blinded, effect sizes shrank. That is the normal history of an effect that was partly artefact.
Is an IV infusion the same as what was trialled?
No. Trials delivered cells into the coronary arteries or the heart muscle itself, in a catheterisation laboratory or operating theatre.
Should I try this instead of my medication?
No. Four drug classes have large randomised evidence and substantial mortality benefit in heart failure. That is where the demonstrated benefit is.
What is DREAM-HF?
A trial of mesenchymal precursor cells in ischaemic heart failure that reported on mortality and major morbidity, particularly in patients with inflammation.
Requesting a medical evaluation
Nothing on this page establishes whether any treatment is appropriate for you. That needs your history, your imaging and your current medications read by a clinician. If you would like that review, send your records and we will tell you honestly whether there is anything worth discussing — including when the answer is no.
This page is general information, not medical advice, and does not create a doctor–patient relationship. Regenerative treatments discussed here are in most cases investigational. Discuss any treatment with a clinician who knows your history.