Fast T2 gradient-spin-echo (T2-GraSE) mapping for myocardial edema quantification: first in vivo validation in a porcine model of ischemia/reperfusion

Background: Several T2-mapping sequences have been recently proposed to quantify myocardial edema by providing T2 relaxation time values. However, no T2-mapping sequence has ever been validated against actual myocardial water content for edema detection. In addition, these T2-mapping sequences are either time-consuming or require specialized software for data acquisition and/or post-processing, factors impeding their routine clinical use. Our objective was to obtain in vivo validation of a sequence for fast and accurate myocardial T2-mapping (T2 gradient-spin-echo [GraSE]) that can be easily integrated in routine protocols. Methods: The study population comprised 25 pigs. Closed-chest 40 min ischemia/reperfusion was performed in 20 pigs. Pigs were sacrificed at 120 min (n = 5), 24 h (n = 5), 4 days (n = 5) and 7 days (n = 5) after reperfusion, and heart tissue extracted for quantification of myocardial water content. For the evaluation of T2 relaxation time, cardiovascular magnetic resonance (CMR) scans, including T2 turbo-spin-echo (T2-TSE, reference standard) mapping and T2-GraSE mapping, were performed at baseline and at every follow-up until sacrifice. Five additional pigs were sacrificed after baseline CMR study and served as controls. Results: Acquisition of T2-GraSE mapping was significantly (3-fold) faster than conventional T2-TSE mapping. Myocardial T2 relaxation measurements performed by T2-TSE and T2-GraSE mapping demonstrated an almost perfect correlation (R-2 = 0.99) and agreement with no systematic error between techniques. The two T2-mapping sequences showed similarly good correlations with myocardial water content: R-2 = 0.75 and R-2 = 0.73 for T2-TSE and T2-GraSE mapping, respectively. Conclusions: We present the first in vivo validation of T2-mapping to assess myocardial edema. Given its shorter acquisition time and no requirement for specific software for data acquisition or post-processing, fast T2-GraSE mapping of the myocardium offers an attractive alternative to current CMR sequences for T2 quantification.This work was supported by a competitive grant from the Ministry of Economy and Competitiveness (MINECO) through the Carlos III Institute of Health -Fondo de Investigacion Sanitaria (PI13/01979)-, the Fondo Europeo de Desarrollo Regional (FEDER, RD: SAF2013-49663-EXP), and in part by the FP7-PEOPLE-2013-ITN Next generation training in cardiovascular research and innovation-Cardionext. Rodrigo Fernandez-Jimenez is recipient of a Rio Hortega fellowship from the Ministry of Economy and Competitiveness through the Instituto de Salud Carlos III, and a FICNIC fellowship from the Fundacio Jesus Serra, the Fundacion Interhospitalaria de Investigacion Cardiovascular (FIC) and the Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC). Javier Sanchez-Gonzalez is an employee of Philips Healthcare. Jaume Aguero is a FP7-PEOPLE-2013-ITN-Cardionext fellow. Carlos Galan-Arriola is recipient of a ``Contrato Predoctoral de Formacion en Investigacion en Salud (PFIS), FI14/00356´´. This study forms part of a Master Research Agreement (MRA) between CNIC and Philips Healthcare. Borja Ibanez is supported by the Red de Investigacion Cardiovascular (RIC) of the Spanish Ministry of Health (RD 12/0042/0054). The CNIC is supported by the Spanish Ministry of Economy and Competitiveness and the Pro-CNIC Foundation.S

β2-Adrenoceptors and GRK2 as Potential Biomarkers in Patients With Chronic Pulmonary Regurgitation

Pulmonary regurgitation (PR) is a frequent complication after repair of congenital heart disease. Three different GRK isoforms (GRK2, GRK5, and GRK3) and two β-adrenoceptors (β1-AR and β2-AR) are present in peripheral blood mononuclear cells (PBMC) and their expression changes as a consequence of the hemodynamic and neurohumoral alterations that occur in some cardiovascular diseases. Therefore, they could be useful as biomarkers in PR. A prospective study was conducted to describe the expression (TaqMan Gene Expression Assays) of β-ARs and GRKs in PBMC isolated (Ficoll® gradient) from patients with severe PR before and after pulmonary valve replacement and establish if this expression correlates to clinical status. 23 patients with severe PR were included and compared with 22 healthy volunteers (controls). PR patients before the PVR had a significantly lower expression of β2-AR (513.8 ± 261.2 mRNA copies) vs. controls (812.5 ± 497.2 mRNA copies), so as GRK2 expression (503.4 ± 364.9 copies vs. 858.1 ± 380.3 mRNA copies). The expression of β2-AR and GRK2 significantly decreases in symptomatic and asymptomatic patients, as well as in patients under treatment with beta-blockers and non-treated patients. The expression of β2-AR and GRK2 in PR patients recovers the normal values after pulmonary valve replacement (754,8 ± 77,1 and 897,8 ± 87,4 copies, respectively). Therefore, changes in the expression of β2-AR and GRK2 in PBMC of PR patients, could be considered as potential biomarkers to determine clinical decisions.This study has been supported by a research grant from the Ministry of Economy and Competitiveness of Spain (SAF2013-45362-R).S

R2 prime (R2') magnetic resonance imaging for post-myocardial infarction intramyocardial haemorrhage quantification.

To assess whether R2* is more accurate than T2* for the detection of intramyocardial haemorrhage (IMH) and to evaluate whether T2' (or R2') is less affected by oedema than T2* (R2*), and thus more suitable for the accurate identification of post-myocardial infarction (MI) IMH. Reperfused anterior MI was performed in 20 pigs, which were sacrificed at 120 min, 24 h, 4 days, and 7 days. At each time point, cardiac magnetic resonance (CMR) T2- and T2*-mapping scans were recorded, and myocardial tissue samples were collected to quantify IMH and myocardial water content. After normalization by the number of red blood cells in remote tissue, histological IMH increased 5.2-fold, 10.7-fold, and 4.1-fold at Days 1, 4, and 7, respectively. The presence of IMH was correlated more strongly with R2* (r = 0.69; P = 0.013) than with T2* (r = -0.50; P = 0.085). The correlation with IMH was even stronger for R2' (r = 0.72; P = 0.008). For myocardial oedema, the correlation was stronger for R2* (r = -0.63; P = 0.029) than for R2' (r = -0.50; P = 0.100). Multivariate linear regressions confirmed that R2* values were significantly explained by both IMH and oedema, whereas R2' values were mostly explained by histological IMH (P = 0.024) and were little influenced by myocardial oedema (P = 0.262). Using CMR mapping with histological validation in a pig model of reperfused MI, R2'more accurately detected IMH and was less influenced by oedema than R2* (and T2*). Further studies are needed to elucidate whether R2' is also better suited for the characterization of post-MI IMH in the clinical setting.This study was partially supported by a competitive grant from the Carlos III Institute of Health-Fondo de Investigacion Sanitaria and the European Regional Development Fund (ERDF/FEDER) (PI16/02110), the Spanish Ministry of Science, Innovation and Universities (MICIU), ERDF/FEDER SAF2013-49663-EXP, by the Comunidad de Madrid (S2017/BMD-3867 RENIM-CM) and cofunded with European structural and investment funds. This study forms part of a Master Research Agreement between the CNIC and Philips Healthcare. This research program is part of an institutional agreement between FIIS Fundacion Jimenez Diaz and the CNIC. The CNIC is supported by the Ministry of Science, Innovation and Universities MICIU the Instituto de Salud Carlos III (ISCiii), and the Pro CNIC Foundation, and is a Severo Ochoa Center of Excellence (award SEV-2015-0505). X.R. has received support from the DYSEC-CNIC CARDIOJOVEN fellowship program. R.F.-J. is a recipient of funding from the European Union Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie (Agreement No. 707642).S

Dynamic Edematous Response of the Human Heart to Myocardial Infarction Implications for Assessing Myocardial Area at Risk and Salvage

BACKGROUND: Clinical protocols aimed to characterize the post-myocardial infarction (MI) heart by cardiac magnetic resonance (CMR) need to be standardized to take account of dynamic biological phenomena evolving early after the index ischemic event. Here, we evaluated the time course of edema reaction in patients with ST-segment-elevation MI by CMR and assessed its implications for myocardium-at-risk (MaR) quantification both in patients and in a large-animal model. METHODS: A total of 16 patients with anterior ST-segment-elevation MI successfully treated by primary angioplasty and 16 matched controls were prospectively recruited. In total, 94 clinical CMR examinations were performed: patients with ST-segment-elevation MI were serially scanned (within the first 3 hours after reperfusion and at 1, 4, 7, and 40 days), and controls were scanned only once. T2 relaxation time in the myocardium (T2 mapping) and the extent of edema on T2-weighted short-tau triple inversion-recovery (ie, CMR-MaR) were evaluated at all time points. In the experimental study, 20 pigs underwent 40-minute ischemia/reperfusion followed by serial CMR examinations at 120 minutes and 1, 4, and 7 days after reperfusion. Reference MaR was assessed by contrast-multidetector computed tomography during the index coronary occlusion. Generalized linear mixed models were used to take account of repeated measurements. RESULTS: In humans, T2 relaxation time in the ischemic myocardium declines significantly from early after reperfusion to 24 hours, and then increases up to day 4, reaching a plateau from which it decreases from day 7. Consequently, edema extent measured by T2-weighted short-tau triple inversion-recovery (CMR-MaR) varied with the timing of the CMR examination. These findings were confirmed in the experimental model by showing that only CMR-MaR values for day 4 and day 7 postreperfusion, coinciding with the deferred edema wave, were similar to values measured by reference contrast-multidetector computed tomography. CONCLUSIONS: Post-MI edema in patients follows a bimodal pattern that affects CMR estimates of MaR. Dynamic changes in post-ST-segment-elevation MI edema highlight the need for standardization of CMR timing to retrospectively delineate MaR and quantify myocardial salvage. According to the present clinical and experimental data, a time window between days 4 and 7 post-MI seems a good compromise solution for standardization. Further studies are needed to study the effect of other factors on these variables.This study was partially supported by a competitive grant from the Spanish Society of Cardiology (Proyectos de Investigacion Traslacional en Cardiologia de la Sociedad Espanola de Cardiologia 2015, for the project Caracterizacion tiSUlar miocaRdica con resonancia magnetica en pacientes tras inFarto agudo de mioCardio con elevacioN de ST sometidos a angloplastia Coronaria primaria. Estudio SURF-CNIC), by a competitive grant from the Carlos III Institute of Health-Fondo de Investigacion Sanitaria- and the European Regional Development Fund (ERDF/FEDER) (PI10/02268 and PI13/01979), the Spanish Ministry of economy, industry, and competitiveness (MEIC) and ERDF/FEDER SAF2013-49663-EXP. Dr Fernandez-Jimenez holds a FICNIC fellowship from the Fundacio Jesus Serra, the Fundacion Interhospitalaria de Investigacion Cardiovascular, and the Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), and Dr Aguero is a FP7-PEOPLE-2013-ITN-Cardionext fellow. This study forms part of a Master Research Agreement between the CNIC and Philips Healthcare, and is part of a bilateral research program between Hospital de Salamanca Cardiology Department and the CNIC. This research program is part of an institutional agreement between FIIS-Fundacion Jimenez Diaz and CNIC. The CNIC is supported by the MEIC and the Pro CNIC Foundation, and is a Severo Ochoa Center of Excellence (MEIC award SEV-2015-0505).S

Combination Proximal Pulmonary Artery Coiling and Distal Embolization Induces Chronic Elevations in Pulmonary Artery Pressure in Swine

Pulmonary hypertension (PH) is associated with aberrant vascular remodeling and right ventricular (RV) dysfunction that contribute to early mortality. Large animal models that recapitulate human PH are essential for mechanistic studies and evaluating novel therapies; however, these models are not readily accessible to the field owing to the need for advanced surgical techniques or hypoxia. In this study, we present a novel swine model that develops cardiopulmonary hemodynamics and structural changes characteristic of chronic PH. This percutaneous model was created in swine (n=6) by combining distal embolization of dextran beads with selective coiling of the lobar pulmonary arteries (2 procedures per lung over 4 weeks). As controls, findings from this model were compared with those from a standard weekly distal embolization model (n=6) and sham animals (n=4). Survival with the combined embolization model was 100%. At 8 weeks after the index procedure, combined embolization procedure animals had increased mean pulmonary artery pressure (mPA) and pulmonary vascular resistance (PVR) compared to the controls with no effect on left heart or systemic pressures. RV remodeling and RV dysfunction were also present with a decrease in the RV ejection fraction, increase in the myocardial performance index, impaired longitudinal function, as well as cardiomyocyte hypertrophy, and interstitial fibrosis, which were not present in the controls. Pulmonary vascular remodeling occurred in both embolization models, although only the combination embolization model had a decrease in pulmonary capacitance. Taken together, these cardiopulmonary hemodynamic and structural findings identify the novel combination embolization swine model as a valuable tool for future studies of chronic PH

Intracoronary Administration of Allogeneic Adipose Tissue-Derived Mesenchymal Stem Cells Improves Myocardial Perfusion But Not Left Ventricle Function, in a Translational Model of Acute Myocardial Infarction

Background-Autologous adipose tissue-derived mesenchymal stem cells (ATMSCs) therapy is a promising strategy to improve post-myocardial infarction outcomes. In a porcine model of acute myocardial infarction, we studied the long-term effects and the mechanisms involved in allogeneic ATMSCs administration on myocardial performance. Methods and Results-Thirty-eight pigs underwent 50 minutes of coronary occlusion; the study was completed in 33 pigs. After reperfusion, allogeneic ATMSCs or culture medium (vehicle) were intracoronarily administered. Follow-ups were performed at short (2 days after acute myocardial infarction vehicle-treated, n=10; ATMSCs-treated, n=9) or long term (60 days after acute myocardial infarction vehicle-treated, n=7; ATMSCs-treated, n=7). At short term, infarcted myocardium analysis showed reduced apoptosis in the ATMSCs-treated animals (48.6 +/- 6\% versus 55.9 +/- 5.7\% in vehicle; P=0.017); enhancement of the reparative process with up-regulated vascular endothelial growth factor, granulocyte macrophage colony-stimulating factor, and stromal-derived factor-1 alpha gene expression; and increased M2 macrophages (67.2 +/- 10\% versus 54.7 +/- 10.2\% in vehicle; P=0.016). In long-term groups, increase in myocardial perfusion at the anterior infarct border was observed both on day-7 and day-60 cardiac magnetic resonance studies in ATMSCs-treated animals, compared to vehicle (87.9 +/- 28.7 versus 57.4 +/- 17.7 mL/min per gram at 7 days; P=0.034 and 99 +/- 22.6 versus 43.3 +/- 14.7 22.6 mL/min per gram at 60 days; P=0.0001, respectively). At day 60, higher vascular density was detected at the border zone in the ATMSCs-treated animals (118 +/- 18 versus 92.4 +/- 24.3 vessels/mm(2) in vehicle; P=0.045). Cardiac magnetic resonance-measured left ventricular ejection fraction of left ventricular volumes was not different between groups at any time point. Conclusions-In this porcine acute myocardial infarction model, allogeneic ATMSCs-based therapy was associated with increased cardioprotective and reparative mechanisms and with better cardiac magnetic resonance-measured perfusion. No effect on left ventricular volumes or ejection fraction was observed.This work was supported by grants from Fundacion la Marato de TV3 (122230); Fondo de Investigacion Sanitaria Instituto de Salud Carlos III and Fondo Europeo de Desarrollo Regional (FIS PI14/01682), (RD12/0042/0006), (RD12/0042/0047), (RD12/0019/0029) (TerCel RD16/0011/0006), CIBER Cardiovascular (CB16/11/00403) projects and Ministerio de Educacion y Ciencia (SAF2011-30067-C02-01) (SAF2014-59892). Fernaandez-Jimenez was the recipient of nonoverlapping grants from the Ministerio de Economia, Industria, y Competitividad through the Instituto de Salud Carlos III (Rio Hortega fellowship); and the Fundacion Jesus Serra, the Fundacion Interhospitalaria de Investigacion Cardiovascular (FIC), and the CNIC (FICNIC fellowship). The use of QMass software was partly supported by a scientific collaboration between the CNIC and Medis Medical Imaging Systems BV. The CNIC is supported by the Ministerio de Economia, Industria, y Competitividad (MINECO) and the Pro CNIC Foundation, and is a Severo Ochoa Center of Excellence (MINECO award SEV-2015-0505). This work was also funded by ``la Caixa Banking Foundation, and the Generalitat de Catalunya (SGR 2014, CERCA Programme). This work has been developed in the context of AdvanceCat with the support of ACCIO (Catalonia Trade \& Investment; Generalitat de Catalunya) under the Catalonian ERDF operational program (European Regional Development Fund) 2014-2020.S

Cardiac I-1c Overexpression With Reengineered AAV Improves Cardiac Function in Swine Ischemic Heart Failure

Cardiac gene therapy has emerged as a promising option to treat advanced heart failure (HF). Advances in molecular biology and gene targeting approaches are offering further novel options for genetic manipulation of the cardiovascular system. The aim of this study was to improve cardiac function in chronic HF by overexpressing constitutively active inhibitor-1 (I-1c) using a novel cardiotropic vector generated by capsid reengineering of adeno-associated virus (BNP116). One month after a large anterior myocardial infarction, 20 Yorkshire pigs randomly received intracoronary injection of either high-dose BNP116.I-1c (1.0 × 1013 vector genomes (vg), n = 7), low-dose BNP116.I-1c (3.0 × 1012 vg, n = 7), or saline (n = 6). Compared to baseline, mean left ventricular ejection fraction increased by 5.7% in the high-dose group, and by 5.2% in the low-dose group, whereas it decreased by 7% in the saline group. Additionally, preload-recruitable stroke work obtained from pressure–volume analysis demonstrated significantly higher cardiac performance in the high-dose group. Likewise, other hemodynamic parameters, including stroke volume and contractility index indicated improved cardiac function after the I-1c gene transfer. Furthermore, BNP116 showed a favorable gene expression pattern for targeting the heart. In summary, I-1c overexpression using BNP116 improves cardiac function in a clinically relevant model of ischemic HF

Fast T2 gradient-spin-echo (T2-GraSE) mapping for myocardial edema quantification: first in vivo validation in a porcine model of ischemia/reperfusion

BACKGROUND: Several T2-mapping sequences have been recently proposed to quantify myocardial edema by providing T2 relaxation time values. However, no T2-mapping sequence has ever been validated against actual myocardial water content for edema detection. In addition, these T2-mapping sequences are either time-consuming or require specialized software for data acquisition and/or post-processing, factors impeding their routine clinical use. Our objective was to obtain in vivo validation of a sequence for fast and accurate myocardial T2-mapping (T2 gradient-spin-echo [GraSE]) that can be easily integrated in routine protocols. METHODS: The study population comprised 25 pigs. Closed-chest 40 min ischemia/reperfusion was performed in 20 pigs. Pigs were sacrificed at 120 min (n = 5), 24 h (n = 5), 4 days (n = 5) and 7 days (n = 5) after reperfusion, and heart tissue extracted for quantification of myocardial water content. For the evaluation of T2 relaxation time, cardiovascular magnetic resonance (CMR) scans, including T2 turbo-spin-echo (T2-TSE, reference standard) mapping and T2-GraSE mapping, were performed at baseline and at every follow-up until sacrifice. Five additional pigs were sacrificed after baseline CMR study and served as controls. RESULTS: Acquisition of T2-GraSE mapping was significantly (3-fold) faster than conventional T2-TSE mapping. Myocardial T2 relaxation measurements performed by T2-TSE and T2-GraSE mapping demonstrated an almost perfect correlation (R(2) = 0.99) and agreement with no systematic error between techniques. The two T2-mapping sequences showed similarly good correlations with myocardial water content: R(2) = 0.75 and R(2) = 0.73 for T2-TSE and T2-GraSE mapping, respectively. CONCLUSIONS: We present the first in vivo validation of T2-mapping to assess myocardial edema. Given its shorter acquisition time and no requirement for specific software for data acquisition or post-processing, fast T2-GraSE mapping of the myocardium offers an attractive alternative to current CMR sequences for T2 quantification

Left Ventricular Unloading Using an Impella CP Improves Coronary Flow and Infarct Zone Perfusion in Ischemic Heart Failure

Background-Delivering therapeutic materials, like stem cells or gene vectors, to the myocardium is difficult in the setting of ischemic heart failure because of decreased coronary flow and impaired microvascular perfusion (MP). The aim of this study was to determine if mechanical left ventricular (LV) unloading with the Impella increases coronary flow and MP in a subacute myocardial infarction. Methods and Results-Anterior transmural myocardial infarction (infarct size, 26.0 +/- 3.4\%) was induced in Yorkshire pigs. At 2 weeks after myocardial infarction, 6 animals underwent mechanical LV unloading by Impella, whereas 4 animals underwent pharmacological LV unloading using sodium nitroprusside for 2 hours. LV unloading with Impella significantly reduced end-diastolic volume (-16 +/- 11mL, P=0.02) and end-diastolic pressure (EDP; -32 +/- 23 mm Hg, P=0.03), resulting in a significant decrease in LV end-diastolic wall stress (EDWS) (infarct: 71.6 +/- 14.7 to 43.3 +/- 10.8 kdynes/cm(2) [P=0.02]; remote: 66.6 +/- 20.9 to 40.6 +/- 13.3 kdynes/cm(2) [P=0.02]). Coronary flow increased immediately and remained elevated after 2 hours in Impella-treated pigs. Compared with the baseline, MP measured by fluorescent microspheres significantly increased within the infarct zone (109 +/- 81\%, P=0.003), but not in the remote zone. Although sodium nitroprusside effectively reduced LV-EDWS, 2 (50\%) of sodium nitroprusside-treated pigs developed profound systemic hypotension. A significant correlation was observed between the infarct MP and EDWS (r(2)=0.43, P=0.03), suggesting an important role of EDWS in regulating MP during LV unloading in the infarcted myocardium. Conclusions-LV unloading using an Impella decreased EDWS and increased infarct MP without hemodynamic decompensation. Mechanical LV unloading is a novel and efficient approach to increase infarct MP in patients with subacute myocardial infarction.This study was partly supported by a research grant from ABIOMED Inc (Danvers, MA) (Ishikawa); National Institutes of Health (NIH) grants R01 HL139963 (Ishikawa) and HL117505, HL119046, HL129814, 128072, HL131404, R01HL135093, and P50 HL112324 (Hajjar); American Heart Association-Scientist Development Grant 17SDG33410873 (Ishikawa); and 2 Transatlantic Fondation Leducq grants. Bikou was supported by the Deutsche Herzstiftung. We would like to acknowledge the Gene Therapy Resource Program of the National Heart, Lung, and Blood Institute, NIH.S