Tirzepatide Reduces LV Mass and Paracardiac Adipose Tissue in Obesity-Related Heart Failure: SUMMIT CMR Substudy

Christopher M Kramer; Barry A Borlaug; Michael R Zile M; Dustin Ruff; Joseph M DiMaria; Venu Menon; Yang Ou; Angela M Zarante; Karla C Hurt; Masahiro Murakami; Milton Packer; SUMMIT Trial Study Group

doi:10.1016/j.jacc.2024.11.001

Tirzepatide Reduces LV Mass and Paracardiac Adipose Tissue in Obesity-Related Heart Failure: SUMMIT CMR Substudy

J Am Coll Cardiol. 2024 Nov 5:S0735-1097(24)10414-7. doi: 10.1016/j.jacc.2024.11.001. Online ahead of print.

Authors

Affiliations

¹ Cardiovascular Division, Department of Medicine, University of Virginia Health, Charlottesville, VA. Electronic address: ckramer@virginia.edu.
² Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN.
³ Medical University of South Carolina, Charleston, South Carolina, USA.
⁴ Eli Lilly and Company, Indianapolis, IN.
⁵ Cardiovascular Division, Department of Medicine, University of Virginia Health, Charlottesville, VA.
⁶ Department of Cardiovascular Medicine, Cleveland Clinic, Cleveland, OH.
⁷ Cinme S. A., Buenos Aires, Argentina.
⁸ Baylor Heart and Vascular Institute, Baylor University Medical Center, Dallas, Texas and Imperial College, London UK.

PMID: 39566869
DOI: 10.1016/j.jacc.2024.11.001

Abstract

Background: Obesity is a known risk factor for heart failure with preserved ejection fraction (HFpEF) and is considered a distinct phenotype with more concentric remodeling. Epicardial adipose tissue (EAT) is also increased in obesity-related HFpEF and is associated with adverse events.

Objective: The Cardiac Magnetic Resonance (CMR) Substudy of the SUMMIT trial was aimed to examine the effects of tirzepatide on cardiac structure and function with the underlying hypothesis that it would reduce left ventricular (LV) mass and EAT in obesity-related HFpEF.

Methods: One hundred seventy-five patients with obesity-related HFpEF from the parent study of tirzepatide (2.5mg SQ weekly, increasing to a maximum of 15mg weekly) or matching placebo underwent CMR at baseline, which consisted of multiplanar cine imaging. One hundred six patients completed the CMR and had adequate image quality for analysis of LV and LA structure and function and paracardiac (epicardial plus pericardial) adipose tissue at both baseline and 52 weeks. The prespecified primary endpoint of this substudy was between-group changes in LV mass.

Results: LV mass decreased by 11 g (95% C.I. -19 to -4) in the treated group (n = 50) when corrected for placebo (n =56) (p=0.004). Paracardiac adipose tissue decreased in the treated group by 45 ml (95% C.I. -69 to -22) when corrected for placebo (p<0.001). The change in LV mass in the treated group correlated with changes in body weight (p<0.02) and, tended to correlate with changes in waist circumference and blood pressure (p=0.06 for both). The LV mass change also correlated with changes in LV end diastolic volume and LA end diastolic and end systolic volumes (p<0.03 for all).

Conclusion: The CMR substudy of the SUMMIT trial demonstrated that tirzepatide therapy in obesity-related HFpEF led to reduced LV mass and paracardiac adipose tissue as compared to placebo and the change in LV mass paralleled weight loss. These physiologic changes may contribute to the reduction in heart failure events seen in the main SUMMIT trial.

Keywords: GLP1 agonist; HFpEF; LV mass; cardiac MRI; obesity.