Discordant findings on stress cardiac magnetic resonance imaging and invasive coronary angiography are associated with left ventricular mass

Background In patients with suspected coronary artery disease (CAD) at coronary computed tomography angiography (CTA), further examination can be made by cardiac magnetic resonance (CMR) imaging and by invasive coronary angiography (ICA). However, causes of discordant findings on CMR and ICA have not been thoroughly investigated. Purpose This study aimed to assess the impact of left ventricular mass (LVM) on discordant stress CMR and ICA findings in patients with suspected obstructive CAD at coronary CTA. Methods Patients (n = 354) with suspected obstructive CAD at coronary CTA were referred to both stress CMR and ICA. An abnormal stress CMR was defined as ≥ 2 contiguous segments with a perfusion defect and/or late gadolinium enhancement (LGE) and/or wall motion abnormality. CMR-derived measurements of LVM were sex-adjusted by conversion from grams to percent of predicted. Left ventricular hypertrophy (LVH) was defined as LVM > 136%. Hemodynamically obstructive CAD at ICA was defined as a visual diameter stenosis > 90% or fractional flow reserve (FFR) ≤ 0.80. Results Median LVM was higher in patients with an abnormal CMR than a normal CMR (120% (interquartile range [IQR]: 109-135) vs. 112% (IQR: 100-125), respectively, p < 0.001), but similar in patients with and without hemodynamically obstructive CAD (116% (IQR: 104-131) vs. 114% (IQR: 102-126), p = 0.222). In binary groups based on findings on stress CMR (normal/abnormal) and on ICA (presence/no presence of hemodynamically obstructive CAD), median LVM was highest in patients with discordant abnormal CMR and no hemodynamically obstructive CAD (124% (IQR: 120-137)). Within the same group, ICA-derived measures of index of microvascular resistance (IMR) were also highest (median IMR: 29 (IQR: 21-38)). Conclusion In patients with suspected obstructive CAD at coronary CTA, discordant findings of an abnormal stress CMR and no hemodynamically obstructive CAD at ICA were associated to both increased LVM and microvascular resistance. Thus, LVH is a potential confounder of the concordance between stress CMR and ICA.