Analysis of Cardiac Computed Tomography: Investigating the Relationship Between Coronary Microvascular Dysfunction and Left Heart Remodeling in Patients With Myocardial Ischemia Due to Non-Obstructive Coronary Artery Disease

Background:Coronary microvascular dysfunction (CMD) represents a key pathological mechanism in patients with ischemia and non-obstructive coronary artery disease (INOCA). Structural and functional abnormalities of the left heart are associated with poor prognosis. The aim of this study was to evaluate the imaging features of early left-heart remodeling associated with CMD in patients with INOCA, including structural and functional changes.Methods:A total of 74 patients underwent coronary computed tomography angiography (CCTA) and invasive physiological assessment. They were classified into two groups: the CMD group (index of microcirculatory resistance (IMR) >25 or coronary flow reserve (CFR) <2.0, n = 36) and the control group (n = 38). Structural parameters included left ventricular mass (LVM), left ventricular mid-diastolic volume (LVMDV), left ventricular mid-systolic volume (LVMSV), left atrial mid-diastolic volume (LAMDV), and left atrial mid-systolic volume (LAMSV), all of which were indexed to body surface area (LVMi, LVMDVi, LVMSVi, LAMDVi, and LAMSVi, respectively). The concentricity index (CI) and left ventricular mid-diastolic wall thickness (LVMDWT) were also evaluated. Functional parameters included LAMDV, LAMSV, the diastolic expansion (DE) index, and left ventricular ejection fraction (LVEF).Results:The CMD group showed significantly higher values for LVMi, LVMDVi, LVMSV, LVMSVi, LAMDV, LAMDVi, LAMSV, and LAMSVi than the control group (p = 0.023, 0.018, 0.025, 0.017, 0.003, 0.002, <0.001, <0.001, respectively). No significant differences were found in the absolute values of LVM, LVMDV, CI, LVMDWT, DE, or LVEF (p = 0.113, 0.080, 0.868, 0.879, 0.406, 0.289, respectively). Multivariable logistic regression analysis revealed that higher LAMSVi (adjusted odds ratio (OR) [AOR] = 1.129, 95% confidence interval (CI) 1.052–1.211, p < 0.001), LAMDVi (AOR = 1.133, 95% CI 1.048–1.225, p = 0.002), LVMi (AOR = 1.072, 95% CI 1.020–1.127, p = 0.006), LVMDVi (AOR = 1.069, 95% CI 1.015–1.126, p = 0.012), and LVMSVi (AOR = 1.084, 95% CI 1.007–1.168, p = 0.032) were independently associated with CMD status in adjusted logistic regression models. These principal multivariable associations remained significant after correction for false discovery rate (all Q <0.05).Conclusions:CMD was associated with adverse left-heart remodeling, as manifested by myocardial hypertrophy, eccentric left ventricular remodeling, atrial dilation, and indices suggestive of early diastolic alterations.