The association between strain, myofiber orientation, and functional outcomes in heart failure with preserved ejection using CMR feature tracking and diffusion tensor imaging

Presenting Author(s)

• 

  Tasnim F. Imran, MD, MPH

  Physician
  Providence VA Medical Center, Alpert Medical School of Brown University

Primary Author(s)

• 

  Tasnim F. Imran, MD, MPH

  Physician
  Providence VA Medical Center, Alpert Medical School of Brown University

Co-Author(s)

• DA

  Daniel Arcuri, RT

  RT
  Providence VA Medical Center
• EM

  Emilio A. Mendiola, BSc

  Research Associate
  Texas A&M University
• RA

  Reza Avazmohammadi, PhD

  Assistant Professor
  Texas A&M University
• 

  Christopher Nguyen, PhD, FSCMR, FACC

  Director, Cardiovascular Innovation Research Center
  Cleveland Clinic
• JG

  Julia G. Gillotti, BA

  Clinical Research Coordinator
  Providence VA Healthcare System
• MA

  Michael Atalay, MD, PhD

  Physician
  Warren Alpert Medical School of Brown University
• WW

  Wen-Chih Wu, MD, MPH

  Physician
  Providence VA Medical Center, Brown University
• GC

  Gaurav Choudhary, MD

  Physician
  Providence VA Medical Center, Warren Alpert Medical School of Brown University

Background: Heart failure with preserved ejection fraction (HFpEF) is a heterogeneous syndrome with limited treatment and significant morbidity and mortality. In vivo CMR tensor imaging (DTI) enables the characterization of myofiber orientation. Myocardial strain from CMR feature tracking is a sensitive marker of subclinical dysfunction. The purpose of this study is to investigate the relationship between myofiber orientation, strain, and functional outcomes in HFpEF.  

Methods: Thirty-eight participants (15 with HFpEF and 23 controls without heart failure) underwent CMR-DTI using a second-order motion compensated, free-breathing spin echo technique. The helix angle transmurality (HAT), slope of the helix angle versus transmural depth from the left ventricular (LV) endocardium to epicardium, was calculated from the LV septum and free wall. Cine short axis, 2, and 4 chamber views were used to derive global radial strain (GRS), global circumferential strain (GCS), and global longitudinal strain (GLS). A composite strain score representing collective distortional deformation in the myocardium was derived as follows: Sqrt [ (GLS-GRS)^2 + (GCS-GRS)^2 + (GLS-GCS)^2]. Participants underwent a 6-minute walk test and a cardiomyopathy questionnaire (KCCQ) to assess self-perception of health.

Results: Participants with HFpEF had a mean age of 72 ± 7 years, BMI 33 kg/m², 67% had diabetes mellitus and all had hypertension. Those with HFpEF had greater mean extracellular volume (ECV) (32% vs 26%, p=0.0001) compared to controls. Mean GLS was -12.4 ± 2.8%, GCS -13.2 ± 3.4% and GRS 17.9 ± 4.2% in the HFpEF group, vs GLS -15 ± 2.7%, GCS -17 ± 2.7% and GRS 28 ± 6.5% in the control group (p=0.01, 0.001, 0.0001, respectively) (Table 1). Participants with HFpEF had a significantly lower LV free wall HAT (67º ± 10, vs 79º ± 11, p=0.01). An example of a HAT CMR-DTI image from a participant with HFpEF and control is shown (Fig 1). Free wall HAT moderately correlated with KCCQ score (r=0.53, p=0.0005) and ECV (r=0.51, p=0.008). The composite strain score moderately correlated with KCCQ score (r=0.52, p=0.0006) and 6-minute walk test distance (r=0.3, p=0.04). Analysis of each global strain separately yielded similar results, with GRS being the most significant.

Conclusion: Our data demonstrate a link between myocardial microstructure and subclinical contractility impairment in HFpEF. We also found that myofiber orientation and strain significantly correlated with quality of life scores and 6-minute walk test distance, suggesting a potential role for CMR-DTI and strain to clinically relevant function and outcomes.

A left ventricular short-axis slice obtained from CMR-DTI illustrating the helix angles is shown (left) with 3D fiber angle visualization (right) from a control (top) and patient with HFpEF (bottom).