Association of left ventricular mass with discordant stress cardiac magnetic resonance and coronary angiography

AIMS: This study aimed to determine the impact of left ventricular mass (LVM) on discordant stress cardiac magnetic resonance (CMR) imaging and invasive coronary angiography (ICA) in patients with suspected coronary artery disease (CAD) at coronary computed tomography angiography (CCTA). METHODS AND RESULTS: In this substudy of the Dan-NICAD 2 trial (NCT03481712), 354 patients with suspected obstructive CAD on CCTA were examined with both rest and stress CMR and ICA for invasive physiological measurements. An abnormal stress CMR was defined as ≥2 contiguous segments with a stress perfusion defect, late gadolinium enhancement, or wall motion abnormality. CMR-derived LVM was sex-adjusted by conversion from grams to per cent. Haemodynamically obstructive CAD at ICA was defined as visual diameter stenosis >90% or FFR ≤0.80. LVM was higher in patients with an abnormal stress CMR compared to those with a normal CMR (median difference = 8.0%, P < 0.001). Patients with or without haemodynamically obstructive CAD had similar LVM (median difference = 2%, P = 0.222). Within four binary groups based on normal/abnormal stress CMR and ICA, both median LVM and index of microvascular resistance were higher in patients with discordant abnormal stress CMR and normal ICA than in patients with concordant normal stress CMR and ICA (124% vs. 111%, P = 0.001, and 29 vs. 19, P = 0.072, respectively). CONCLUSION: In patients with suspected obstructive CAD, increased LVM can potentially confound concordance between stress CMR and ICA. This is due to increased microvascular resistance, which decreases the pressure gradient across an epicardial stenosis, resulting in a false high FFR and thus, normal ICA.