Catherine Dao

The Impact of Downstream Coronary Stenosis on Fractional Flow Reserve Assessment of Intermediate Left Main Coronary Artery Disease: Human Validation

OBJECTIVES The aim of this study was to determine the impact of downstream coronary stenosis in the left anterior descending coronary artery (LAD) or left circumflex coronary artery (LCx) on the assessment of fractional flow reserve (FFR) across an intermediate left main coronary artery (LMCA) stenosis in humans with the pressure wire positioned in the nondiseased downstream vessel. BACKGROUND Accurate assessment of intermediate LMCA disease is critical for guiding decisions regarding revascularization. In theory, FFR across an intermediate LMCA stenosis will be affected by downstream disease, even if the pressure wire is positioned in the nondiseased downstream vessel. METHODS After percutaneous coronary intervention of the LAD, LCx, or both, an intermediate LMCA stenosis was created with a deflated balloon catheter. FFR was measured in the LAD and LCx coronary arteries before and after creation of downstream stenosis by inflating an angioplasty balloon within the newly placed stent. The true FFR (FFRtrue) of the LMCA, measured in the nondiseased downstream vessel in the absence of stenosis in the other vessel, was compared with the apparent FFR (FFRapp) measured in the presence of stenosis. RESULTS In 25 patients, 91 pairs of measurements were made, 71 with LAD stenosis and 20 with LCx stenosis. FFRtrue of the LMCA was significantly lower than FFRapp (0.81 ± 0.08 vs. 0.83 ± 0.08, p < 0.001), although the numerical difference was small. This difference correlated with the severity of the downstream disease (r = 0.35, p < 0.001). In all cases in which FFRapp was >0.85, FFRtrue was >0.80. CONCLUSIONS In most cases, downstream disease does not have a clinically significant impact on the assessment of FFR across an intermediate LMCA stenosis with the pressure wire positioned in the nondiseased vessel.

Clinical ResearchCoronaryThe Impact of Downstream Coronary Stenosis on Fractional Flow Reserve Assessment of Intermediate Left Main Coronary Artery Disease: Human Validation

OBJECTIVES The aim of this study was to determine the impact of downstream coronary stenosis in the left anterior descending coronary artery (LAD) or left circumflex coronary artery (LCx) on the assessment of fractional flow reserve (FFR) across an intermediate left main coronary artery (LMCA) stenosis in humans with the pressure wire positioned in the nondiseased downstream vessel. BACKGROUND Accurate assessment of intermediate LMCA disease is critical for guiding decisions regarding revascularization. In theory, FFR across an intermediate LMCA stenosis will be affected by downstream disease, even if the pressure wire is positioned in the nondiseased downstream vessel. METHODS After percutaneous coronary intervention of the LAD, LCx, or both, an intermediate LMCA stenosis was created with a deflated balloon catheter. FFR was measured in the LAD and LCx coronary arteries before and after creation of downstream stenosis by inflating an angioplasty balloon within the newly placed stent. The true FFR (FFRtrue) of the LMCA, measured in the nondiseased downstream vessel in the absence of stenosis in the other vessel, was compared with the apparent FFR (FFRapp) measured in the presence of stenosis. RESULTS In 25 patients, 91 pairs of measurements were made, 71 with LAD stenosis and 20 with LCx stenosis. FFRtrue of the LMCA was significantly lower than FFRapp (0.81 ± 0.08 vs. 0.83 ± 0.08, p < 0.001), although the numerical difference was small. This difference correlated with the severity of the downstream disease (r = 0.35, p < 0.001). In all cases in which FFRapp was >0.85, FFRtrue was >0.80. CONCLUSIONS In most cases, downstream disease does not have a clinically significant impact on the assessment of FFR across an intermediate LMCA stenosis with the pressure wire positioned in the nondiseased vessel.

Multimodality Molecular Imaging of Cardiac Cell Transplantation: Part I. Reporter Gene Design, Characterization, and Optical in Vivo Imaging of Bone Marrow Stromal Cells after Myocardial Infarction.

Purpose To use multimodality reporter-gene imaging to assess the serial survival of marrow stromal cells (MSC) after therapy for myocardial infarction (MI) and to determine if the requisite preclinical imaging end point was met prior to a follow-up large-animal MSC imaging study. Materials and Methods Animal studies were approved by the Institutional Administrative Panel on Laboratory Animal Care. Mice (n = 19) that had experienced MI were injected with bone marrow-derived MSC that expressed a multimodality triple fusion (TF) reporter gene. The TF reporter gene (fluc2-egfp-sr39ttk) consisted of a human promoter, ubiquitin, driving firefly luciferase 2 (fluc2), enhanced green fluorescent protein (egfp), and the sr39tk positron emission tomography reporter gene. Serial bioluminescence imaging of MSC-TF and ex vivo luciferase assays were performed. Correlations were analyzed with the Pearson product-moment correlation, and serial imaging results were analyzed with a mixed-effects regression model. Results Analysis of the MSC-TF after cardiac cell therapy showed significantly lower signal on days 8 and 14 than on day 2 (P = .011 and P = .001, respectively). MSC-TF with MI demonstrated significantly higher signal than MSC-TF without MI at days 4, 8, and 14 (P = .016). Ex vivo luciferase activity assay confirmed the presence of MSC-TF on days 8 and 14 after MI. Conclusion Multimodality reporter-gene imaging was successfully used to assess serial MSC survival after therapy for MI, and it was determined that the requisite preclinical imaging end point, 14 days of MSC survival, was met prior to a follow-up large-animal MSC study. (©) RSNA, 2016 Online supplemental material is available for this article.

Multimodality Molecular Imaging of Cardiac Cell Transplantation: Part II. In Vivo Imaging of Bone Marrow Stromal Cells in Swine with PET/CT and MR Imaging

Purpose To quantitatively determine the limit of detection of marrow stromal cells (MSC) after cardiac cell therapy (CCT) in swine by using clinical positron emission tomography (PET) reporter gene imaging and magnetic resonance (MR) imaging with cell prelabeling. Materials and Methods Animal studies were approved by the institutional administrative panel on laboratory animal care. Seven swine received 23 intracardiac cell injections that contained control MSC and cell mixtures of MSC expressing a multimodality triple fusion (TF) reporter gene (MSC-TF) and bearing superparamagnetic iron oxide nanoparticles (NP) (MSC-TF-NP) or NP alone. Clinical MR imaging and PET reporter gene molecular imaging were performed after intravenous injection of the radiotracer fluorine 18-radiolabeled 9-[4-fluoro-3-(hydroxyl methyl) butyl] guanine ((18)F-FHBG). Linear regression analysis of both MR imaging and PET data and nonlinear regression analysis of PET data were performed, accounting for multiple injections per animal. Results MR imaging showed a positive correlation between MSC-TF-NP cell number and dephasing (dark) signal (R(2) = 0.72, P = .0001) and a lower detection limit of at least approximately 1.5 × 10(7) cells. PET reporter gene imaging demonstrated a significant positive correlation between MSC-TF and target-to-background ratio with the linear model (R(2) = 0.88, P = .0001, root mean square error = 0.523) and the nonlinear model (R(2) = 0.99, P = .0001, root mean square error = 0.273) and a lower detection limit of 2.5 × 10(8) cells. Conclusion The authors quantitatively determined the limit of detection of MSC after CCT in swine by using clinical PET reporter gene imaging and clinical MR imaging with cell prelabeling. (©) RSNA, 2016 Online supplemental material is available for this article.

Cytokines profile of reverse cardiac remodeling following transcatheter aortic valve replacement

OBJECTIVE Previous studies have suggested that cytokines and growth factors may predict ventricular recovery following aortic valve replacement (AVR). The primary objective of this study was to identify cytokines that predict ventricular recovery following transcatheter AVR (TAVR). METHODS We prospectively enrolled 121 consecutive patients who underwent TAVR. Standard echocardiographic assessment at baseline, 1-month and 1-year after TAVR included left ventricular (LV) mass index (LVMI) and global longitudinal strain (GLS). Blood samples were obtained at the time of the procedure to measure cytokines using a 63-plex Luminex platform. Partial least squares-discriminant analysis was performed to identify cytokines associated with ventricular remodeling and function at baseline as well as 1 year after TAVR. RESULTS The mean age was 84 ± 9 years, with a majority of male subjects (59%), a mean LVMI of 120.4 ± 45.1 g/m2 and LVGLS of -13.0 ± 3.2%. On average, LV mass decreased by 8.1% and GLS improved by 20.3% at 1 year following TAVR. Among cytokines assayed, elevated hepatocyte growth factor (HGF) emerged as a common factor significantly associated with worse baseline LVMI and GLS as well as reduced ventricular recovery (p < 0.005). Other factors associated with ventricular recovery included a select group of vascular growth factors, inflammatory mediators and tumor necrosis factors, including VEGF-D, ICAM-1, TNFβ, and IL1β. CONCLUSION We identified a network of cytokines, including HGF, that are significantly correlated with baseline LVMI and GLS, and ventricular recovery following TAVR.

THE INFLAMMASOME PATHWAY IS ASSOCIATED WITH ADVERSE VENTRICULAR REMODELING FOLLOWING TRANSCATHETER AORTIC VALVE REPLACEMENT

Background: Aortic stenosis (AS) results in progressive ventricular remodeling and heart failure. There is strong evidence that inflammatory cytokines play a key role in this maladaptive process, however, it is unclear how they affect the ventricular remodeling following transcatheter aortic valve

TCT-737 Baseline growth differentiation factor 15 (GDF15) is an independent predictor of reverse left atrial remodeling and mortality at 1-year following Transcatheter Aortic Valve Replacement.

METHODS Retrospective analysis of consecutive TAVR patients for whom pre procedural angles were predicted by cardiac imaging specialists using two methods: manual multiplanar reformations (MR) and the semi-automatic optimal angle graph (OAG). The distributions of predicted versus actual cranial caudal (CRA\CAU, Y axis) and right and left anterior oblique (RAO\LAO, X axis) angles are presented in scatter plots. Paired analysis was used to compare the distributions and means following definition of equal distribution as the null hypothesis. The difference between the two dimensional distributions and means were compared to a zero bivariate normal distribution and mean.

ACCURACY AND REPRODUCIBILITY OF CONTRAST ENHANCED AND NON-ENHANCED COMPUTED TOMOGRAPHY FOR PREDICTING THE ANGIOGRAPHIC DEPLOYMENT ANGLE IN TRANSCATHETER AORTIC VALVE REPLACEMENT (TAVR)

Methods: CT projection angles were retrospectively determined by 2 independent readers in 58 patients who underwent contrast (n=39) or noncontrast (n=19) CT before TAVR with the Edwards SAPIEN valve. CT angles were derived by visually aligning the nadirs of the sinuses of Valsalva in a single 3D plane that traversed the hinges of all 3 leaflets. Accuracy of predicted CT angles was defined as the absolute difference between the cranial-caudal (CRA-CAU) angle from CT and corresponding angiographic CRA-CAU angle at the rotational (LAO-RAO) angle that was used for deployment. Intraobserver and interobserver variability were evaluated with Pearson correlation and Bland-Altman analyses. Angiographic angles were categorized according to the visual overlap of stent struts immediately after deployment, and graded excellent if the projected distance between the superior margins of the stent was less than half a cell height, fair if it was between half to a whole cell, and poor if it was greater than a full cell.

COMPUTED TOMOGRAPHY BASED PREDICTION OF ANGIOGRAPHIC DEPLOYMENT ANGLES MAY REDUCE PROCEDURE TIME AND CONTRAST MEDIUM VOLUME FOR TRANSCATHETER AORTIC VALVE REPLACEMENT

Accurate device positioning in Transcatheter Aortic Valve Replacement (TAVR) requires selection of an angiographic projection angle perpendicular to the annulus plane. The objective of this study was to prospectively assess the ability of pre-procedural computed tomography (CT) to predict a suitable