The Effects of Hydrogen Gas Inhalation on Adverse Left Ventricular Remodeling After Percutaneous Coronary Intervention for ST-Elevated Myocardial Infarction - First Pilot Study in Humans
Katsumata Y, Sano F, Abe T, Tamura T, Fujisawa T, Shiraishi Y, Kohsaka S, Ueda I, Homma K, Suzuki M, Okuda S, Maekawa Y, Kobayashi E, Hori S, Sasaki J, Fukuda K, Sano M. · Circ J. 2017;81(7):940-947.
Study at a glance
Twenty people with suspected heart attack received hydrogen-containing gas or oxygen during emergency coronary treatment. The main scan-based outcome did not improve significantly with hydrogen. Some later heart-function measurements favored hydrogen, but only 11 patients had both scans. Sequential treatment groups, early termination and conflicting statistical descriptions prevent a causal clinical-benefit conclusion.
Human
Adults aged 20–80 presenting within 24 hours of STEMI symptoms and selected for primary percutaneous coronary intervention; shock, severe hypoxia and cardiac arrest were excluded.
Mask delivery of 1.3% H₂ with 26% O₂ from emergency-room arrival, before coronary angiography and through primary PCI. · Reported H₂ concentration 1.3% with 26% O₂. An independent achieved-exposure validation was not established here.
During coronary angiography and primary PCI; exact exposure minutes were not reported. Primary CMR at day 7; serial CMR at six months.
Primary cardiac salvage index: 50.0 ± 24.3% with hydrogen versus 60.1 ± 20.1% control (P = 0.43), a null result. ST resolution, myocardial blush, TIMI flow, peak CK and CK area did not differ significantly. In the 11 serial-CMR participants, LV stroke-volume-index change was +9.2 ± 7.1 versus −1.4 ± 7.2 mL/m²; the abstract/figure gives P = 0.03 and the body P = 0.04, an unresolved discrepancy. LVEF change was 11.0 ± 9.3 versus 1.7 ± 8.3 percentage points (P = 0.11), not significant despite contradictory prose. At six months, LVSVI was 45.5 ± 6.9 versus 32.2 ± 6.3 (P = 0.009); LVEF was 65.7 ± 5.2 versus 48.3 ± 18.2 (P = 0.05). These small exploratory subsets do not establish causal clinical benefit.
Sequential nonrandomized groups, early termination at 20 versus a planned 80, post-treatment exclusions concentrated in the hydrogen arm, and only 13 primary/11 serial CMR observations. Age and infarct-site imbalances and multiple exploratory surrogate outcomes limit interpretation. No mortality or clinical-benefit conclusion is established.
What kind of evidence is this?
Human
Single-centre prospective pilot with nonrandomized sequential allocation: the first 10 patients received hydrogen and the next 10 control gas. Patient and endpoint-assessor blinding was reported.
Cardiovascular and circulatory health
Inhaled H₂
Information not yet classified
Some editorial classification fields are still pending. The source-reported outcomes and result are shown below; Hydrogenology does not infer a positive or negative signal from prose automatically.
Methods
Adults aged 20–80 presenting within 24 hours of STEMI symptoms and selected for primary percutaneous coronary intervention; shock, severe hypoxia and cardiac arrest were excluded.
20 treated and included in safety assessment (10 hydrogen, 10 control). Full analysis: 17 (7 hydrogen, 10 control) after 3 non-STEMI exclusions, all in the hydrogen arm. Primary day-7 CMR: 13 (6 hydrogen, 7 control). Serial day-7/six-month CMR: 11 (6 hydrogen, 5 control).
During coronary angiography and primary PCI; exact exposure minutes were not reported. Primary CMR at day 7; serial CMR at six months.
Mask delivery of 1.3% H₂ with 26% O₂ from emergency-room arrival, before coronary angiography and through primary PCI.
H₂-containing inhaled gas with 26% oxygen; not pure hydrogen.
Reported H₂ concentration 1.3% with 26% O₂. An independent achieved-exposure validation was not established here.
An exact study gas flow was not established. The article states that oxygen flow above 10 L/min prevents attaining 1.3% H₂; this is an equipment constraint, not a measured treatment flow.
26% O₂ in both study gas conditions.
26% O₂ without H₂ and the same standard STEMI care.
Outcomes and reported result
Primary: CMR cardiac salvage index at day 7. Exploratory perfusion, myocardial-injury and serial cardiac-function measures.
Primary cardiac salvage index: 50.0 ± 24.3% with hydrogen versus 60.1 ± 20.1% control (P = 0.43), a null result. ST resolution, myocardial blush, TIMI flow, peak CK and CK area did not differ significantly. In the 11 serial-CMR participants, LV stroke-volume-index change was +9.2 ± 7.1 versus −1.4 ± 7.2 mL/m²; the abstract/figure gives P = 0.03 and the body P = 0.04, an unresolved discrepancy. LVEF change was 11.0 ± 9.3 versus 1.7 ± 8.3 percentage points (P = 0.11), not significant despite contradictory prose. At six months, LVSVI was 45.5 ± 6.9 versus 32.2 ± 6.3 (P = 0.009); LVEF was 65.7 ± 5.2 versus 48.3 ± 18.2 (P = 0.05). These small exploratory subsets do not establish causal clinical benefit.
The available main full text was reviewed for methods, results, limitations and declarations. Uncertainties, supplementary-source limits and conflicting findings are stated in this record.
No severe adverse event was reported among the 10 hydrogen recipients; two severe control events were renal injury and stent restenosis. Hydrogen recipients included one rash and one constipation event. One hydrogen patient withdrew because of severe recurrent vomiting during catheterization, which authors did not attribute to hydrogen. These findings are not an absence of adverse events.
A reported association, difference or mechanism is not automatically a clinical benefit.
Limitations and applicability
Sequential nonrandomized groups, early termination at 20 versus a planned 80, post-treatment exclusions concentrated in the hydrogen arm, and only 13 primary/11 serial CMR observations. Age and infarct-site imbalances and multiple exploratory surrogate outcomes limit interpretation. No mortality or clinical-benefit conclusion is established.
Selected emergency-PCI patients in this small pilot; no causal efficacy or general safety conclusion.
Taiyo Nippon Sanso Corporation provided gas and funding; authors state that the funder had no role in the study.
Research grants from Taiyo Nippon Sanso were disclosed for Y.K., T.T., K.H., M. Suzuki, E.K. and M. Sano.
No single-study GRADE certainty rating is assigned. Read how records and evidence assessments are prepared.
Sources and record status
PMID: 28321000 · DOI: 10.1253/circj.cj-17-0105
Complete final publisher article in J-STAGE HTML, including Tables 1–3 and figure captions. Referenced supplementary Tables S1–S4 were not separately checked.
AI-assisted editorial review of the available main full text, 29 October 2026. No independent clinical or statistical assessment has been performed.
Methods including allocation; sample-size/statistical analysis; Results; Tables 1–3; Discussion/limitations; conflicts and grants.
AI-assisted editorial review of the available main full text, 29 October 2026. Complete final publisher article in J-STAGE HTML, including Tables 1–3 and figure captions. Referenced supplementary Tables S1–S4 were not separately checked.
UMIN00006825, as printed in the article; the identifier was not independently reconciled.
29 October 2026
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