Correlation of Noninvasive Cardiac MRI Measures of Left Ventricular Myocardial Function and Invasive Pressure-Volume Parameters in a Porcine Ischemia-Reperfusion Model

Purpose: To assess the correlation between noninvasive cardiac MRI-derived parameters with pressure-volume (PV) loop data and evaluate changes in left ventricular function after myocardial infarction (MI). Materials and Methods: Sixteen adult female swine were induced with MI, with six swine used as controls and 10 receiving platelet-derived growth factor-AB (PDGF-AB). Load-independent measures of cardiac function, including slopes of end-systolic pressure-volume relationship (ESPVR) and preload recruitable stroke work (PRSW), were obtained on day 28 after MI. Cardiac MRI was performed on day 2 and day 28 after infarct. Global longitudinal strain (GLS) and global circumferential strain (GCS) were measured. Ventriculo-arterial coupling (VAC) was derived from PV loop and cardiac MRI data. Pearson correlation analysis was performed. Results: GCS ( r = 0.60, P = .01), left ventricular ejection fraction (LVEF) ( r = 0.60, P = .01), and cardiac MRI-derived VAC ( r = 0.61, P = .01) had a significant linear relationship with ESPVR. GCS ( r = 0.75, P < .001) had the strongest significant linear relationship with PRSW, followed by LVEF ( r = 0.67, P = .005) and cardiac MRI-derived VAC ( r = 0.60, P = .01). GLS was not significantly correlated with ESPVR or PRSW. There was a linear correlation ( r = 0.82, P < .001) between VAC derived from cardiac MRI and from PV loop data. GCS (-3.5% +/- 2.3 vs 0.5% +/- 1.4, P = .007) and cardiac MRI-derived VAC (-0.6 +/- 0.6 vs 0.3 +/- 0.3, P = .001) significantly improved in the animals treated with PDGF-AB 28 days after MI compared with controls. Conclusion: Cardiac MRI-derived parameters of MI correlated with invasive PV measures, with GCS showing the strongest correlation. Cardiac MRI-derived measures also demonstrated utility in assessing therapeutic benefit using PDGF-AB.