Abstract 14155: Handgrip Exercise Provoked High Sensitivity Cardiac Troponin I Increase in Women With No Obstructive Coronary Artery Disease: Relations to Myocardial Function

Background: Among women with signs and symptoms of ischemia and no obstructive coronary arteries (INOCA) around 10% develop heart failure with preserved ejection fraction (HFpEF). Mechanisms contributing to AMI and HFpEF progression in INOCA are poorly understood.

Purpose: To characterize clinical profile and stress cardiac magnetic resonance imaging (CMRI) myocardial features of INOCA patients with and without increased troponin levels in response to handgrip exercise.

Methods: Women with suspected INOCA underwent cardiac MRI and invasive coronary function testing (CFT), including coronary sinus (CS) cannulation, handgrip exercise testing, and serial CS plasma sampling before, after 3 minutes of isometric handgrip stress at 30% of maximal voluntary contraction, and after 5 minutes of recovery. High sensitivity cardiac troponin I (hsTnI) was measured using commercial immunoassay (R-PLEX, Meso Scale Discovery, Rockville, MD) and compared using t-tests.

Results: A total of 51 women with complete data were included, of whom 31 (60.7%) had handgrip provoked increases in hsTnI levels from baseline, while 20 (39.2%) did not. Baseline characteristics are shown in Table. Patients with increased hsTnI levels had greater impaired global longitudinal strain rates and early diastolic strain rates (radial and circumferential) compared to those without increased hsTnI. No significant differences were observed in myocardial perfusion reserve index (MPRI).

Conclusion: Women with INOCA demonstrating objective evidence of handgrip exercise provoked myocardial injury exhibit evidence of myocardial dysfunction not related to myocardial perfusion. Further prospective research is needed to understand the sequence of relations between coronary microvascular dysfunction contribution to HFpEF progression.