CMR-Analysis (including machine learning)
Maggie Mallabone
Student Researcher
University of Calgary
CALGARY, Alberta, Canada
James White, MD
Professor of Cardiology
Stephenson Cardiac Imaging Centre
Calgary, Alberta, Canada
Fereshteh Hasanzadeh, MSc
Master Student in Cardiovascular and Respiratory Science
Cumming School of Medicine, University of Calgary
Calgary, Alberta, Canada
Steven Dykstra, MSc, BSc
PhD Student
Libin Cardiovascular Institute of Alberta, University of Calgary
Calgary, Alberta, Canada
Dina Labib, MD, PhD, FSCMR
PhD student
Libin Cardiovascular Institute of Alberta, University of Calgary
Calgary, Alberta, Canada
Sandra Rivest, RN
Research nurse
Libin Cardiovascular Institute of Alberta, University of Calgary
Calgary, Alberta, Canada
Jacqueline Flewitt, MSc
Research Collaborations Coordinator
Libin Cardiovascular Institute of Alberta, University of Calgary
Calgary, Alberta, Canada
Andrew G. Howarth, MD, PhD
Clinical Co-director
Libin Cardiovascular Institute of Alberta, University of Calgary
Calgary, Alberta, Canada
Carmen P. Lydell, MD
Clinical Co-director
Libin Cardiovascular Institute of Alberta, University of Calgary
Calgary, Alberta, Canada
Nowell M. Fine, MD
Associate professor of cardiology
Libin Cardiovascular Institute
Calgary, Alberta, Canada
Robert J. Miller, MD
Associate professor of Cardiology
University of Calgary, Canada
CMR provides objective value in the characterization of dilated cardiomyopathy (DCM) through quantification of chamber remodelling, function, and replacement fibrosis. Whether there are sex-based unique distributions and prognostic value for these markers has not been well explored. Using sex-specific z-scores of quantitative markers versus a health reference cohort, we studied deviations from the nominal state of health seen in female versus male DCM cohorts. The respective prevalence, patterns, and burden of replacement fibrosis were also examined. Sex-specific associations with major adverse cardiac events (MACE) were then assessed.
Methods:
DCM patients with LVEF < 50%, LVEDVi ≥2SD above sex-specific reference mean values, were studied from the CIROC Registry. All patients underwent baseline health questionnaires, collection of laboratory, pharmacy, and 12-lead ECG data, and were followed for the composite MACE outcome of all-cause mortality, heart failure hospital admission, survived cardiac arrest, VT/VF, cardiac transplant or LVAD implantation. A 100-subject healthy reference cohort was recruited to derive sex-specific reference values for quantitative CMR markers and Z-scores for chamber volumetry and function markers.
Results:
Among 596 DCM subjects included, 179 (30%) were female. Baseline demographics, health profiles, and CMR markers are provided in Table 1. Females were slightly older than males, but showed a similar distribution of comorbidities, NYHA class, and heart failure medications. Sex-adjusted Z-scores for CMR markers showed matched LVEF reduction, and greater LV dilation in females while RV dysfunction and LA dilation were less pronounced. Females showed significantly lower prevalence of mid-wall striae fibrosis (28% vs 38%, p=0.019). Over a median follow-up of 3.9 years, the primary composite outcome occurred with similar frequency between sexes, occurring in 210 (50%) males and 91 (51%) females (HR 0.99; p=0.94); HF admission accounted for 48% of first events. Sex-specific regression showed LVEF, LVEDV, LV Mass, RVEF, and LA volume were associated with MACE in females and males. However, mid-wall striae fibrosis was only associated with the primary composite outcome in males (HR 1.6, p=0.001), losing its prognostic value in females (HR 1.2, p=0.53).
Conclusion:
Despite similar LVEF reduction, female DCM patients showed worse LV dilation but paradoxically lower burden of replacement fibrosis. The latter was accompanied by less LA dilation and reduction in RV function. The associations of replacement fibrosis with MACE also appeared to differ between sexes. These findings raise potentially important considerations regarding sex on the phenotypic presentation of DCM, and the respective value of CMR-based markers to predict future outcomes.