ST上昇型心筋梗塞に対するPCI後の左室リモデリングへの水素ガス吸入の影響：ヒトにおける初の臨床パイロット試験
A prospective, open-label, rater-blinded pilot study enrolled 20 STEMI patients randomized to 1.3% hydrogen gas inhalation (with 26% oxygen) or a control arm (26% oxygen alone) during primary PCI. Cardiac magnetic resonance imaging at day 7 revealed no statistically significant between-group difference in the cardiac salvage index. At 6-month follow-up, however, the hydrogen inhalation group demonstrated numerically greater improvements in LV stroke volume index (HI: +9.2 mL/m² vs. control: −1.4 mL/m²; P=0.03) and LV ejection fraction (HI: +11.0% vs. control: +1.7%; P=0.11). No serious adverse events attributable to hydrogen inhalation were recorded, supporting the feasibility and safety of this approach. The authors note that the study was underpowered for efficacy conclusions and call for a larger confirmatory trial.
Selective scavenging of reactive oxygen species, particularly hydroxyl radicals, by inhaled hydrogen is proposed to reduce oxidative damage during ischemia-reperfusion, thereby limiting cardiomyocyte loss and subsequent adverse left ventricular remodeling.
For inhalation applications of molecular hydrogen, the lower flammability limit (LFL) deserves careful handling. The classical 4% figure applies to closed-system mixtures; the practical inhalation-environment threshold is 10%. Even pure-hydrogen output (the UFL 75% paradox) passes through the flammable range at the air–gas boundary. High-concentration (66% / 100%) inhalers are documented in the Japanese Consumer Affairs Agency accident-information database and are not recommended.
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https://h2-papers.org/en/papers/28321000