AUTHOR=Le Thu-Thao , Huang Weiting , Singh Gurpreet K. , Toh Desiree-Faye , Ewe See Hooi , Tang Hak Chaw , Loo Germaine , Bryant Jennifer A. , Ang Briana , Tay Edgar Lik-Wui , Soo Wern Miin , Yip James Wei-Luen , Oon Yen Yee , Gong Lingli , Lunaria Josephien B. , Yong Quek Wei , Lee Evelyn Min , Yeo Poh Shuan Daniel , Chai Siang Chew , Goh Ping Ping , Ling Lee Fong , Ong Hean Yee , Richards Arthur Mark , Delgado Victoria , Bax Jeroen J. , Ding Zee Pin , Ling Lieng-Hsi , Chin Calvin W. L. 

TITLE=Echocardiographic Global Longitudinal Strain Is Associated With Myocardial Fibrosis and Predicts Outcomes in Aortic Stenosis

JOURNAL=Frontiers in Cardiovascular Medicine

VOLUME=Volume 8 - 2021

YEAR=2021

URL=https://www.frontiersin.org/journals/cardiovascular-medicine/articles/10.3389/fcvm.2021.750016

DOI=10.3389/fcvm.2021.750016

ISSN=2297-055X

ABSTRACT=Aims
Left ventricular ejection fraction is the conventional measure used to guide heart failure management, regardless of underlying etiologies.  Left ventricular global longitudinal strain (LV-GLS) by speckle tracking echocardiography (STE) is a more sensitive measure of intrinsic myocardial function. We aim to establish LV-GLS as a marker of replacement myocardial fibrosis on cardiovascular magnetic resonance (CMR) and validate the prognostic value of LV-GLS thresholds associated with fibrosis.

Methods and results
LV-GLS thresholds of replacement fibrosis were established in the derivation cohort: 151 patients (57±10 years; 58% males) with hypertension who underwent STE to measure LV-GLS and CMR. Prognostic value of the thresholds was validated in a separate outcome cohort: 261 patients with moderate-severe aortic stenosis (AS; 71±12 years; 58% males; NYHA functional class I-II) and preserved LVEF 50%. Primary outcome was a composite of cardiovascular mortality, heart failure hospitalization, and myocardial infarction.  

In the derivation cohort, LV-GLS demonstrated good discrimination (c-statistics 0.74 [0.66-0.83]; P<0.001) and calibration (Hosmer-Lemeshow 2= 6.37; P=0.605) for replacement fibrosis. In the outcome cohort, 47 events occurred over 16 [3.3, 42.2] months. Patients with LV-GLS >-15.0% (corresponding to 95% specificity to rule-in myocardial fibrosis) had the worst outcomes compared to patients with LV-GLS <-21.0% (corresponding to 95% sensitivity to rule-out myocardial fibrosis) and those between -21.0 and -15.0% (log-rank P<0.001). LV-GLS offered independent prognostic value over clinical variables, AS severity and echocardiographic LV mass and E/e’.

Conclusion
LV-GLS thresholds associated with replacement myocardial fibrosis is a novel approach to risk-stratify patients with AS and preserved LVEF.