Cardiac magnetic resonance (CMR) feature tracking (FT) of left ventricular (LV) myocardial strain metrics successfully predicted heart failure, myocardial infarction, stroke and death in a new general population study of the UK Biobank. The findings — from 45,700 participants over a median 3-year follow-up period — show that CMR-FT measurements of various LV parameters are “valuable imaging markers,” the study’s authors said, calling for further research to define and standardize normal ranges. The study was published Monday online ahead of the Aug 13 issue of the Journal of the American College of Cardiology, with lead authors from Queen Mary University of London and Bart Heart Centre, UK’s Sucharitha Chadalavada, MBBS. Although CMR-led myocardial strain measurements are already known to be a “sensitive marker” to predict adverse outcomes in many cardiac disease states, the researchers said this study is the first to assess the prognostic value in the general population. Only GLS independently predicted death The 45,700 participants came from the UK Biobank: a repository of health and lifestyle data on approximately 500,000 UK-based volunteers aged 40 to 69 years, collected between 2006 and 2010. The current study’s participants each had usable data from CMR scans at time of image analysis. The subjects had an average age of 65 (± 8 years) at baseline imaging, 52% were female and 96% were white. Medical conditions recorded included coronary artery disease for 5% (n = 2,130), hypercholesterolemia in 25% (n = 11,453), hypertension in 29% (n = 13,354) and diabetes in 5% (n = 2,200). Univariable and multivariable Cox models were used to assess heart failure, myocardial infarction, stroke and death outcomes, and each myocardial strain marker — LV global longitudinal (GLS), circumferential (GCS), and radial strain (GRS) — separately. The average values of CMR parameters were within normal limits for the study population, the researchers noted. Clinical outcome endpoints were then defined using hospital episodes statistics data. All 3 myocardial strain markers were independent predictors of heart failure in fully adjusted multivariable Coz regression models (GLS hazard ratio [HR]: 1.84; 95% confidence interval [CI]: 1.66-2.05; GCS HR: 1.72; 95% CI: 1.54-1.92; GRS HR: 0.54; 95% CI: 0.48- 0.61). The three strain markers were also independent predictors of myocardial infarction in fully adjusted multivariable Cox regression models (GLS HR: 1.30; 95% CI: 1.17- 1.45; GCS HR: 1.25; 95% CI: 1.11-1.40; and GRS HR: 0.80 95% CI: 0.71-0.91). Stroke could also be independently predicted by all 3 strain markers in fully adjusted multivariable models (GLS HR: 1.24; 95% CI: 1.09-1.41; GCS HR: 1.22 05% CI: 1.06-1.41; and GRS HR: 0.81; 95% CI: 0.70-0.94). All 3 strain markers were also independently predictive of each outcome in models additionally adjusted for conventional imaging markers. However, although “all strain markers were independent predictors (incrementally above some respective conventional LV imaging markers) for the morbidity outcomes […] only GLS predicted death independently,” the authors said, specifying that only GLS provided independent prognostic value above clinical features (HR: 1.19; 95% CI: 1.09-1.31) and LV mass (HR: 1.18; 95% CI: 1.07-1.30). “GRS provided marginal independent prognostic value above clinical features (HR: 0.90; 95% CI: 0.81-0.99; P = 0.04) but not when LV mass was also included in the model. Only GLS models remained significant after applying multiple testing correction, and none provided evidence of incremental value,” the authors noted. Need to standardize The researchers concluded by calling for further researcher to define and standardize normal ranges, as well as disease-specific and risk factor-specific thresholds for CMR-derived myocardial, to facilitate broad clinical use. “These results provide some important reminders about the clinical use of strain,” Thomas Marwick, MBBS, PhD, MPH, from the Baker Heart and Diabetes Institute, Australia, said in an accompanying editorial. Marwick noted that the high feasibility, automation, and easy quality control of CMR have driven its use in several epidemiologic studies. He stressed that there is already a lot of observational data from 2-dimensional echocardiography (2DE) strain measurements — the “most widely available” test for ejection fraction. “What we need are intervention trials of conditions where strain is more useful than conventional measures, such as in stage B HF and cancer treatment-related cardiac dysfunction. To date, we have not found that CMR strain is superior to 2DE strain in these settings, but more data are needed.” Sources: Chadalavada A, Fung K, Rauseo E, et al. Myocardial Strain Measured by Cardiac Magnetic Resonance Predicts Cardiovascular Morbidity and Death. J Am Coll Cardiol 2024;84:648-659. Marwick T. Use of Feature Tracking to Predict Outcome in Epidemiologic Studies Using Cardiac Magnetic Resonance Imaging. J Am Coll Cardiol 2024;84:660-662. Image Credit: Anastasiia – stock.adobe.com