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Evaluating change of function after revascularization in patients with multi vessel coronary artery disease, severely reduced left ventricular systolic function and no scar on CMR imaging Alexander Ivanov, James Yossef, Ambreen Mohamed, Joshua Socolow, Iossif Gulkarov, Berhane Worku, Pairoj Chattranukulchai, Anthony Tortolani, Terrence Sacchi, Mohamad G Ghosn, Dipan J Shah, John D Grizzard, Robert W Biederman, Igor Klem, John Heitner

Background Elevated high sensitivity cardiac troponin (cTnT) levels, LVEF, and the degree of myocardial replacement fibrosis (RF) have been shown to be significantly associated with cardiovascular outcomes. However, the relationship amongst them has yet to be studied. Cardiac magnetic resonance (CMR) has become the gold standard for viability imaging and accurately characterizing RF. Recently, a new technique has been employed to quantify diffuse myocardial fibrosis via assessment of myocardial extracellular volume (ECV). The current study sought to investigate the association between ECV, RF, LVEF, LV mass (LVM) and cTnT levels.

Background The measurement of the extent of myocardial replacement fibrosis in non-ischemic cardiomyopathy (NICMP) has been shown to correlate with clinical cardiac outcomes Although delayed enhancement cardiovascular magnetic resonance (DE-CMR) has been established as the reference standard for assessing myocardial replacement fibrosis (RF), this imaging process is unable to identify more subtle diffuse interstitial fibrosis (IF) in the myocardium. Newer T1 mapping after the administration of gadolinium contrast has been shown to adequately assess increases in extracellular volume (ECV) fraction, which occurs in the setting of IF. In this study, we sought to evaluate the relationship between RF and IF in patients with NICMP. Methods Eighty consecutive patients with NICMP underwent DECMR and T1 mapping using a Modified Look-Locker Inversion recovery (MOLLI) technique. RF extent was determined by analysis of the DE-CMR images. The extracellular gadolinium contrast agent in the myocardium was compared to the amount of contrast in the blood in the dynamic steady state in order to estimate the ECV fraction. In order to decrease statistical variance, regions of localized RF detected on imaging were avoided when measuring the ECV. Results There was RF evident in 49 patients (61%). Patients with RF had higher ECV compared to those without RF (36.1 ± 10.7 and 31.9 ± 6.7 respectively; p = 0.04). The left ventricular ejection fraction (LVEF) and stroke volume (SV) were significantly lower in patients with ECV > 30% (p 30 has significantly lower LVEF (p = 0.02). There was a significant increase in ECV for patients with RF of more than 5% of LV myocardium (p 5% had ECV of 32.60 ± 6.20 and 44.70 ± 13.91%, respectively. In linear regression analysis, ECV is positively associated with scar burden (Beta weight = 0.527, p < 0.001). Conclusions The results of this study suggest that there is a positive relationship between increased RF and ECV in patients with NICMP. Our data shows that stroke volume and left ventricular ejection fraction are significantly decreased in patients with RF and in those with an increased ECV. Funding None.

Background Cardiac MRI has been shown to be the gold standard for noninvasive assessment of myocardial fibrosis. The extent of fibrosis has been associated with worse outcomes in patients undergoing CABG surgery. The presence of fibrosis and associated clinical features of patients with chronic mitral regurgitation undergoing mitral valve repair have not been described. The objective of this study is to examine prognostic value of preoperative myocardial fibrosis assessment by cardiac MRI in patients with chronic mitral regurgitation undergoing mitral valve repair.

Background Atrial Fibrillation (AF) is the most common arrhythmia in clinical practice; cathete ra blation (AFCA) is aw idespread treatment. Determinants of AFCA success and post-AFCA left atrial remodeling are poorly understood. Delayed Enhancement Cardiac Magnetic Resonance (DE-CMR) has been used to image LA scar post-AFCA and its relation to ablation outcome. Here we explored the role of postablation LA scar in subsequent cardiac remodeling. Methods We correlated post AFCA scar with cardiac volumes and function including LA volume, LV ejection fraction (LVEF), and LV cardiac output (LVCO). In a retrospective analysis, we identified 46 patients who underwent AFCA -pulmonary vein antral isolation in whom DE-CMR was obtained before and after AFCA (174 ± 160 days postablation). In 20 patients, a repeat AFCA procedure was performed due to recurrent AF. DE-CMR procedure was performed utilizing a navigated 3D inversion recovery gradient echo sequence (Siemens 1.5T Avanto or 3.0T Verio) approximately 15 minutes after administration of 0.2 mmol/kg Gadolinium (Magnevist). Scans were ECG-gated and acquired during a 150 ms window in mid-diastole with navigator-gating and fat suppression. We have developed an image analysis method and graphical user interface (GUI) to semi-automatically quantify hyperenhanced regions (scar) in the entire LA wall. Scar was quantified semi-automatically as fraction of LA contour in every slice from base to roof. STATA/IC 13.0 was used for statistical analysis. Two-way Interclass Correlation (ICC) for rater agreement was tested for LA perimeter and LA scar detection between two independent readers for 40 MRI slices. Variable normality was assessed with the Shapiro-Wilk test. The Wilcoxon signed-rank test was used to determine statistical significance between non-parametric variables in pre and post AFCA. Results ICC indicates similarity between observers in both LA Perimeter (ICC: 0.785, CI: 0.59-0.886, p < 0.05) and LA Scar (ICC: 0.609, CI: -0.14-0.844, p < 0.05). The extent of LA Scar was higher in postablation (Median: 8.62, IQR: 5.43-16.4) DE-CMR compared to baseline

Background Graft dysfunction after lung transplantation is typically attributable to infection or rejection. In the absence of these entities, structural cardiovascular (CV) abnormalities need to be sought. At our center this evaluation typically includes a myriad of diagnostic tests: echocardiography, chest computed tomographic angiography, nuclear medicine lung perfusion imaging, and right heart catheterization (RHC). This study was designed to evaluate the utility of a novel comprehensive CMR protocol for identification of all post-operative structural CV complications in lung transplant recipients. Methods We enrolled 80 consecutive lung transplant recipients who were referred for CMR evaluation of CV abnormalities. There were 47 men and 33 women; mean age 56.7 ±13.6 years; 55 Caucasians, 9 Hispanic, 13 African American, and 3 Asian. Underlying restrictive disease was present in 39 subjects, obstructive disorders in 22, and other disorders in 19. Forty-three subjects had undergone double lung transplant, while 37 subjects had single lung transplant (23 left lung, and 14 right lung). The comprehensive CMR protocol included complete short and long axis cine imaging (SSFP) to evaluate cardiac size and function; ECG gated spin echo imaging to assess pericardial thickness; contrast enhanced MRA of the pulmonary arterial (PA) and venous (PV) systems to assess for anastomotic site stenosis; phase contrast velocity flow mapping to assess anastomotic site peak velocity and right and left PA flow fraction; and inversion recovery SSFP to evaluate for myocardial fibrosis. Results All 80 subjects completed CMR imaging without difficulty and none were excluded from this analysis for reasons of image quality. The mean LVEF was 66.4±9.23%, mean RVEF was 54.37±10.45%, right and left PAs flow were 2.6±1.21 and 2.6± 1.31 liter/min, respectively. Specific complications identified and the prevalence is shown in Table 1. Patients with moderate or severe PA or PV anastomotic site stenosis underwent RHC and intravascular ultrasound, which confirmed CMR findings; patients with severe stenosis underwent stenting of the respective vessel. Patients with CMR evidence of pericardial constriction underwent pericardiectomy with improvement in symptoms. Conclusions A comprehensive CMR protocol can be a useful single noninvasive test for the detection of structural cardiovascular (CV) abnormalities after lung transplantation. Funding Not applicable.

Background Left atrial (LA) radiofrequency (RF) ablation has become routine treatment for atrial fibrillation (AF) but still suffers from AF recurrence requiring a repeat procedure. LA-RF ablation success rates vary between 53% and 85%. Delayed-enhancement Cardiac Magnetic Resonance (DE-CMR) can be used to noninvasively visualize LA hyperenhancement (scar). We have utilized DECMR to quantify LA scar extent post LA-RF-ablation and related this measure to AF recurrence.