Extracellular myocardial volume in patients with aortic stenosis

Journal article

Background: Myocardial fibrosis is a key mechanism of left ventricular decompensation in aortic stenosis and can be quantified using cardiovascular magnetic resonance (CMR) measures such as extracellular volume fraction (ECV%). Outcomes following aortic valve intervention may be linked to the presence and extent of myocardial fibrosis.

Objectives: This study sought to determine associations between ECV% and markers of left ventricular decompensation and post-intervention clinical outcomes.

Methods: Patients with severe aortic stenosis underwent CMR, including ECV% quantification using modified Look-Locker inversion recovery–based T1 mapping and late gadolinium enhancement before aortic valve intervention. A central core laboratory quantified CMR parameters.

Results: Four-hundred forty patients (age 70 ± 10 years, 59% male) from 10 international centers underwent CMR a median of 15 days (IQR: 4 to 58 days) before aortic valve intervention. ECV% did not vary by scanner manufacturer, magnetic field strength, or T1 mapping sequence (all p > 0.20). ECV% correlated with markers of left ventricular decompensation including left ventricular mass, left atrial volume, New York Heart Association functional class III/IV, late gadolinium enhancement, and lower left ventricular ejection fraction (p < 0.05 for all), the latter 2 associations being independent of all other clinical variables (p = 0.035 and p < 0.001). After a median of 3.8 years (IQR: 2.8 to 4.6 years) of follow-up, 52 patients had died, 14 from adjudicated cardiovascular causes. A progressive increase in all-cause mortality was seen across tertiles of ECV% (17.3, 31.6, and 52.7 deaths per 1,000 patient-years; log-rank test; p = 0.009). Not only was ECV% associated with cardiovascular mortality (p = 0.003), but it was also independently associated with all-cause mortality following adjustment for age, sex, ejection fraction, and late gadolinium enhancement (hazard ratio per percent increase in ECV%: 1.10; 95% confidence interval [1.02 to 1.19]; p = 0.013).

Conclusions: In patients with severe aortic stenosis scheduled for aortic valve intervention, an increased ECV% is a measure of left ventricular decompensation and a powerful independent predictor of mortality.

Authors: Everett, RJ; Treibel, TA; Fukui, M; Lee, H; Rigolli, M

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Elsevier
• Journal: Journal of the American College of Cardiology
• Volume: 75
• Issue: 3
• Pages: 304-316
• Publication date: 2020-01-20
• Acceptance date: 2019-11-04
• DOI: 10.1016/j.jacc.2019.11.032
• EISSN: 1558-3597
• ISSN: 0735-1097
• Pmid: 31976869
• Language: English
• Keywords: aortic stenosis; diffuse myocardial fibrosis; FFR; T1 mapping; cardiovascular magnetic resonance