Valvular & structural heart diseaseSecondary analysis

Myocardial Fibrosis and Early Intervention in Asymptomatic Patients With Severe Aortic Stenosis

JAMA CardiolPublished

  • Post hoc analysis of a randomised clinical trial
  • 24 cardiac centres, UK and Australia

Trial conducted August 2017 to October 2022; data analyzed October 2024 through June 2025

Authors' conclusion

In this study, in asymptomatic patients with severe aortic stenosis, higher midwall fibrosis burden was associated with adverse outcomes. There was no demonstrable heterogeneity by the degree of midwall fibrosis for the treatment effects of early surgical or transcatheter aortic valve replacement compared to clinical surveillance.

Study context

Population
Asymptomatic patients with severe AS and midwall fibrosis on CMR
Participants
224 patients
Comparison
Early intervention vs Conservative management
Primary endpoint
All-cause death or unplanned AS-related hospitalization
Follow-up
Median 42 months

Primary result

As reported in the abstract

All-cause death or unplanned AS-related hospitalization, by midwall fibrosis burden
Hazard ratio (95% CI)
Fibrosis burden (per 1% increase)association with primary end point
1.23(1.08–1.37)
Early intervention vs Conservative managementhigh fibrosis burden (above median); 12 of 59 vs 17 of 53
0.62(0.29–1.28)
Low fibrosis burden (below median): no difference in primary outcome between intervention groups
HR, 1.05; 95% CI, 0.39-2.86
No interaction between randomization arm and midwall fibrosis burden for the primary end point
P for interaction = 0.39

Secondary outcomes

OutcomeEarly interventionConservative managementHR (95% CI)
Unplanned AS-related hospitalization, per 1% fibrosis increase1.22 (1.03–1.40)
All-cause death, per 1% fibrosis increase1.17 (0.98–1.35)
All-cause death (high fibrosis burden subgroup)15%19%0.84 (0.33–2.07)
Unplanned AS-related hospitalization (high fibrosis burden subgroup)7%25%0.27 (0.08–0.77)

Original publication

Myocardial Fibrosis and Early Intervention in Asymptomatic Patients With Severe Aortic Stenosis. JAMA Cardiol. Published 1 June 2026. doi:10.1001/jamacardio.2026.0654

Summarised from the published abstract; every number is checked against it