Key findings
- Heart failure development following heart attack was reduced from about 16% to 6%
- Heart failure hospital readmissions dropped from about 10% to 3%
- Heart function (LVEF) improved by an average of 5.9 percentage points compared to standard care
- No serious adverse events reported
We know that following a heart attack, your risk of developing heart failure significantly increases. Depending on your age and other health factors,that risk can increase anywhere from 10% to 30% over a few years. One of the reasons is that, unfortunately, cardiomyocytes (heart muscle cells) have a limited ability to regenerate, and even small areas of damage can lead to long-term weakening of the heart.
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Key findings
- Heart failure development following heart attack was reduced from about 16% to 6%
- Heart failure hospital readmissions dropped from about 10% to 3%
- Heart function (LVEF) improved by an average of 5.9 percentage points compared to standard care
- No serious adverse events reported
We know that following a heart attack, your risk of developing heart failure significantly increases. Depending on your age and other health factors,that risk can increase anywhere from 10% to 30% over a few years. One of the reasons is that, unfortunately, cardiomyocytes (heart muscle cells) have a limited ability to regenerate, and even small areas of damage can lead to long-term weakening of the heart.
Just last week, researcherspublished the results of their Phase 3 trial in The British Medical Journal, using umbilical-derived mesenchymal stem cells (MSCs) infused directly into the heart, and the results look promising.
The PREVENT-TAHA8 study is among the largest and longest-running investigations to date examining stem cells for this indication. Current treatments for heart attacks have greatly improved survival rates, but many patients are left with weakened heart muscle, which contributes to the risk. While several clinical trials have evaluated stem cell therapies for cardiac repair, the researchers noted that most have focused on surrogate markers such as heart function measurements or have had short follow-up periods.
To address these limitations, the team used clinical heart failure as the primary outcome and followed patients for a median of approximately three years. A total of 420 patients aged 18 to 65 years, all experiencing their first ST-segment elevation myocardial infarction with reduced heart pump function (ejection fraction under 40%), were randomized in a 1:2 ratio to receive either an intracoronary infusion of allogenic Wharton’s jelly-derived mesenchymal stem cells (MSCs) plus standard care, or standard care alone.
The stem cells were infused into the heart within 3-7 days after the heart attack.
Results Show Reduced Heart Failure and Improved Cardiac Function
Of the 396 patients included in the final analysis, 136 received the stem cell infusion, and 260 received standard care. After three years of follow-up, here’s what they found.
With standard care, the risk of developing heart failure was about 1 in 6, while the stem cell group’s risk was about 1 in 20:
- Control Group – 16.08%
- Stem Cell Group – 5.74%
- That’s a relative reduction of about 64%
Of those that did develop heart failure, the risk for hospital readmission for it was about 1 in 9 for standard care, while the stem cell group was about 1 in 40:
- Control Group – 10.77%
- Stem Cell Group – 2.48%
- That’s about a 77% relative reduction
The stem cell group also improved heart function, as measured by left ventricular ejection fraction (LVEF), by approximately 5.88 percentage points (95% CI, 4.00–7.76; P < 0.001).
Additionally, they used a composite endpoint that included cardiovascular death and hospital readmissions for heart failure or recurrent heart attack, which was also significantly lower in the MSC group:
- Control Group – 7.16 events per 100 person-years (person-years is a way of standardizing the follow-up duration across all patients)
- Stem Cell Group – 2.80 events per 100 person-years
- That’s about a 61 % relative reduction in major cardiovascular events compared with standard care.
No serious safety concerns were reported during the study period.
Limitations and next steps
The study is pretty distinctive due to its size, follow-up duration, and focus on clinical endpoints rather than surrogate markers. It’s also unique in that it’s a large, multi-center trial using Wharton’s jelly-derived MSCs, which have several advantages over autologous bone marrow-derived MSCs, including off-the-shelf capability and non-invasive harvest.
There were some limitations, including the inability to use a sham procedure for blinding, and a relatively small number of women enrolled, which restricted some subgroup analyses.
The study was not designed to assess underlying mechanisms, such as changes in heart tissue or inflammation, and longer follow-up may be required to detect impacts on mortality. Of course, further research is necessary to gain a deeper understanding of the mechanisms involved.
TheDoD is also currently running a similar study using IV infusion at the University of Louisville. It’s an exciting time for cardiovascular regeneration.
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BMJ 2025; 391:e083382. DOI: 10.1136/bmj-2024-083382. Published 29 October 2025.