Previous studies have shown that patients with aortic stenosis (AS) and pulmonary hypertension (PHT) have a worse prognosis compared to those with normal pulmonary artery pressure (PAP). However, the prognostic value of PHT in patients with low-flow low-gradient aortic stenosis (LF-LG AS) has not been examined. The present study aimed to evaluate the prognostic value of PHT in patients with LF-LG AS treated conservatively or with aortic valve replacement (AVR).

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Canadian Institutes of Health Research. Background/Introduction Excessive epicardial adipose tissue (EAT) is associated with worse exercise capacity and is thought to play a role in the pathophysiology of heart failure with preserved ejection fraction. Few studies have explored the relationship between EAT, cardiorespiratory fitness in men and women without cardiovascular disease. Purpose To investigate the association between EAT, cardiorespiratory fitness, and physical activity levels in asymptomatic men and women of variable degree of adiposity. Methods A total of 239 participants (43% women) free from cardiovascular disease who underwent concurrent quantification of EAT volume assessed by cardiac magnetic resonance and a cardiopulmonary exercise testing (CPET) (VO2peak [ml/kg/min]) were studied. Physical activity levels/intensity were measured by questionnaire and using pedometer. Participants were categorized into low-EAT, moderate-EAT, and high-EAT groups on the basis of EAT volume. Results Mean age of participants was 49.8 ± 8.3 years, BMI 26.0 ± 3.7 kg/m2 (15% with obesity), waist circumference 89 ± 11 cm, visceral adipose tissue volume 91.3 ± 51.3 cm3, and EAT volume 9.8 ± 3.1 cm3. EAT volume decreased with increment in cardiorespiratory fitness in men and women of variable adiposity (p<0.05). Men and women with high-EAT had worse cardiometabolic profile (visceral adiposity, insulin resistance, high blood pressure, dysglycemia, atherogenic dyslipidemia), and lower cardiorespiratory fitness (VO2peak) than those with low-EAT (all p<0.05). Physical activity levels were comparable across EAT tertiles (p=NS). The association between EAT and cardiorespiratory fitness was no longer significant after controlling for visceral adiposity. Conclusions In men and women of variable degree of adiposity, excessive EAT accumulation is associated with visceral adiposity and worse cardiorespiratory fitness. Further longitudinal studies are needed to understand the interplay between EAT and cardiorespiratory fitness, and the development of obesity-related heart failure features.

As the prevalence of cardiovascular disease remains high, improved strategies are necessary to prevent onset. Although atherosclerosis has been associated with several risk factors, it is commonly identified in young and otherwise healthy populations, reinforcing the importance of developing new universal prevention strategies that may also be applied to individuals without known risk factors. The aim of this study was to determine the interaction of sedentary behavior and physical activity (PA) on cardiovascular health. We aimed to determine the independent and combined impacts of sedentary behavior and physical activity/inactivity on atherosclerosis burden and the cardiometabolic profile.

BACKGROUND AND HYPOTHESISLow circulating levels of insulin-like growth-factor binding protein-2 (IGFBP-2) have been associated with increased adiposity and metabolic alterations such as insulin resistance, dyslipidemia, and non-alcoholic fatty liver disease in individuals with obesity. However, whether IGFBP-2 affects energy metabolism in the early stages of these disorders remains unclear. Herein, we hypothesized that plasma IGFBP-2 concentrations are inversely associated with early liver fat accumulation and alterations in lipid and glucose homeostasis in apparently healthy and asymptomatic men and women.METHODS333 middle-aged Caucasian men and women apparently healthy and without cardiovascular symptoms were enrolled for a cross-sectional cardiometabolic imaging study. Individuals with BMI ≥ 40 kg/m2, cardiovascular disease, dyslipidemia, hypertension, and diabetes were excluded. Fasting glucose and lipid profiles were measured and an oral glucose tolerance test was performed. Liver fat content was assessed by magnetic resonance spectroscopy. Volume of visceral adipose tissue (VAT) was evaluated by magnetic resonance imaging. Plasma IGFBP-2 levels were quantified by ELISA.RESULTSParticipants with low IGFBP-2 levels were characterized by a higher body fat mass (p<0.0001), insulin resistance (p<0.0001), higher plasma triglyceride (TG) (p<0.0001) and lower HDL-cholesterol levels (p<0.0001) in a sex-independent manner. IGFBP-2 levels were inversely correlated with liver fat fraction in both men (r=-0.36, p<0.0001) and women (r=-0.40, p<0.0001). IGFBP-2 concentrations were negatively associated with hepatic fat fraction independently of age and VAT in both men (R2=0.23, p=0.012) and women (R2=0.27, p=0.028).CONCLUSIONSOur findings show that even in asymptomatic, apparently healthy individuals, low IGFBP-2 levels are associated with a more deteriorated cardiometabolic risk profile and with a high hepatic fat content in a VAT-independent manner. However, IGFBP-2 does not appear to influence the established sexual dysmorphism observed for metabolic variables and hepatic fat fraction. Additional studies are required to better understand the relationships between IGFBP-2 and liver fat content.

Tissue injury in acute myocardial infarction has several components, including myocardial edema and cardiomyocyte necrosis. Severe infarction can be complicated by microvascular obstruction (MVO) and hemorrhage (H). MVO has been shown to occur and expand early after reperfusion therapy in animal models. In humans, the presence of MVO is independently associated with adverse ventricular remodelling and outcome. As opposed to animal studies, the time course of evolution of microvascular injury is not well understood in humans, especially in the very acute phase after reperfusion injury. The aim of this pilot study was to investigate the temporal evolution of tissue injury (MVO, infarct size) and ventricular function within the first week after reperfused acute ST-elevation myocardial infarction. The study was approved by the institutional ethics committee and all patients gave written informed consent. A comprehensive cardiac MRI study was performed on day 0 or 1 after reperfused STEMI, and compared to a follow-up CMR study on day 5-7. All 21 patients had received primary PCI and guideline-based medical therapy. The contrast-enhanced CMR study assessed LV volumetric parameters, LVEF, and quantified edema, necrosis, MVO and hemorrhage. Twenty-one patients were included, of whom twelve had no microvascular injury (I), seven had microvascular obstruction (MVO), and two had hemorrhagic infarcts (H). Thirteen completed the follow-up. At baseline, hemorrhagic MI had larger infarct size, greater MVO, larger edema, larger ventricular end-diastolic volume and lower LVEF than infracts without microvascular injury. Patients with MVO had larger infarcts than patients without microvascular injury, however, this did not lead to a difference in LVEDV or LVEF (table 1). At follow-up, patients with MVO maintained the extent of MVO, e.g. it did neither increase nor decrease in size. Likewise, infarct size, amount of edema, LVEDV and LVEF did not change between day 0/1 and day 5-7, independent of the presence or absence of MVO (table 2). As opposed to animal models, in our patient study we did not observe any expansion of MVO in the first week after reperfused STEMI. Also, there was no change in the extent of edema, infarct size from day 0/1 to day 5-7, in patients with or without MVO. Patients with MVO had larger infarct size from the beginning; the largest infarct size and worst LV function was observed in patients with hemorrhagic myocardial infarction. Patient numbers were limited in this pilot study.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Despite highly encouraging animal studies, clinical trials have revealed marginal therapeutic efficacy of stem cell transplantation for ischemic cardiomyopathy (IC). Intracardiac delivery of unselected bone marrow cells have yielded inconsistent results in first-generation trials which indicated preference for use of selected stem cells in subsequent studies. Our team investigated the intra-cardiac delivery of autologous CD133+ cells in patients suffering from ischemic cardiomyopathy in COMPARE-AMI (recent infarct) and IMPACT-CABG (steady state cardiac insufficiency) phase II randomized trials respectively, counting in total 80 patients. While safety and feasibility endpoints were met, these studies demonstrate improvement of cardiac functional recovery in some but not in all patients. With available banked stem cells from these trials, our goal is to identify genomic signatures responsible for therapeutic efficacy in order to identify ideal allogeneic donor cell populations or novel pre-treatments ('pharmaco-optimization') that could replicate cellular phenotypes of functionally competent CD133+. Expression of 20,800 genes were analyzed in high-throughput AmpliSeq using CD133+ from patients classified as responders (≥3% LVEF) and non-responders according to cardiac fMRI comparing pre- and post-treatment changes. RNA-Seq differential expression analysis was performed using the package limma and gene set enrichment analysis was performed on Gene Ontology (GO) pathways using nominally significant genes. Heatmaps where produced using R on significantly associated GO terms. CD133+ from acute MI patients in COMPARE-AMI (n=13) compared to chronic MI patients in IMPACT-CABG (n=12) preferentially overexpress genes associated with cell cycle regulation, DNA synthesis/ repair, metabolic processes, telomere activity and cardiac development. Of these, cell cycle progression and cellular metabolism related genes are associated with COMPARE-AMI clinical responders (n=5). Moreover, FACS analysis revealed unaltered levels of surface markers for CD45+, CD34+, CD106+, CD184+, CD49d+ and CD105+ for responder and non-responder patients, whereas CD90+, a marker associated with different hematopoietic stem cell phenotypes including inhibition of proliferation and differentiation showed increased expression in non-responders (n=8). In this exploratory study we had the unique opportunity to use banked CD133+ cells to identify genes modulated during acute and chronic MI, as well as transcriptomic signatures associated with clinical response. Such signatures have guided our efforts in developing potent pharmaco-optimizers, and this data is used to query various databases containing large numbers of bioactive compounds to further refine stem cell optimization strategies for the purpose of replicating clinical responsiveness phenotypes in cells ex vivo prior to transplantation in our next-generation trials.

Background: Therapeutic benefits of cell therapy remain modest due to varying cell phenotypes from different patients and the poor survival of transplanted cells. IMPACT-CABG and COMPARE-AMI trials represent the first North American phase II randomized studies of autologous CD133+ stem cells delivered in the heart post myocardial infarction (MI). Cells were delivered in patients suffering from chronic ischemic cardiomyopathy through transepicardial injections during CABG procedure (IMPACT-CABG) and by intracoronary route during PCI and stenting <7 days following MI (COMPARE-AMI). With banked stem cells, we set out to identify the CD133+ expression phenotypes in both patient populations and identify transcriptomic signatures responsible for therapeutic effectiveness.

Therapeutic benefits of cell therapy remain mitigated due to factors including cell phenotypes and their poor survival and function in pathologic heart. Whereas first generation of advances focused on cell selection, delivery and a broad understanding of mechanisms involved in therapy success, the next advances will come from decoding complex biological pathways underpinning regenerative potential of cells from different patients. IMPACT-CABG trial represents the first North American phase II multicenter randomized study of intra-myocardial delivery of autologous CD133+ cells in chronic cardiomyopathy patients undergoing CABG. With banked stem cells from this trial, we have the opportunity to correlate the patient's clinical outcome with cellular gene expression profiles. Our goal is to identify genomic signatures responsible for therapeutic effectiveness and identify pre-treatments from our drug discovery platform that could activate cellular phenotypes replicating those of patients responding to cell therapy. In this exploratory study, expression of 20,800 human genes (Ion AmpliSeq) are analyzed in high-throughput format using CD133+ stem cells from 13 patients classified as responders (≥5% LVEF and/or ≤10% left ventricular volumes) vs non-responders according to cardiac fMRI comparing pre- and 6-month post-treatment changes. Differential expression and pathway analysis are performed using computational tools including DESeq2, GAGE (Generally Applicable GeneSet Enrichment for Pathways Analysis), PathView and R. Pathway analyses show significant association in responders with genes related to cytokine production, activity and receptor interaction, cell adhesion molecules, regulation of kinase cascades (p < 0.05). Several other comparisons were performed to characterize gene expression vs patient demographics. The general pattern of activity was replicated in human mesenchymal stem cells (hMSC) by short ex vivo pharmacological conditioning with Celastrol, an HSP90 targeting compound. Celastrol activates kinases PI3K/Akt and ERK1/2 within 5min, upregulates HSP70 and HO-1 mRNAs (>30-fold) as well as VEGF in cells maintained in normoxic (2.7-fold) or hypoxic condition (1.3-fold, p < 0.05). Celastrol improves hMSC viability during hypoxic or oxidative challenges. Proteomic analysis of culture conditioned-media shows upregulation (>2-fold) of over 100 proteins, including HSPs, growth factors, antioxidants, cytokines indicating improved paracrine potential. IMPACT-CABG responder's stem cells express gene sets associated with paracrine potential, cell engraftment and survival that can be mimicked by an ex vivo pharmacological pre-conditioning to improve stem cell therapeutic potential. Information gathered will be used in IMPACT-CABG II trial involving a first of its kind precision pharmaco-optimization strategy (USPTO62/350,258 patent pending) to harness the full potential of cellular cardiomyoplasty using CD133+ cells.

A previous study in patients with aortic stenosis (AS) showed that the relationship between aortic valve calcification (AVC) and mean transvalvular gradient (MG) was different between bicuspid (BAV) and tricuspid aortic valve (TAV) patients, especially in younger patients. While TAV and older BAV patients had good AVC-MG correlation, no association was found in young BAV patients. This difference in young patients with BAV was particularly notable in women where the combination of high MG but no or minimal AVC was often present. We hypothesized that there might be a sex-related difference in the relationship between AVC and AS hemodynamic severity (MG) according to the aortic valve morphology (BAV vs TAV). Forty (40) BAV and 40 TAV patients with AS were matched for sex and for AVC indexed to the aortic annulus area (i.e. AVC density; AVCd). AVC by the Agatston method was measured by computed tomography and patients also underwent a Doppler-echocardiography to assess the AS hemodynamic severity (MG). The cohort consisted of 75% of men. As expected, TAV patients were older (70±11 vs 53±11, p < 0.0001) and had more risk factors (hypertension, dyslipidemia, diabetes, coronary artery disease) compared to BAV patients (all p < 0.02). AS hemodynamic severity and AVCd were similar in BAV and TAV patients (p>0.21). For the same level of AVCd, men harbored similar MG whether they had a BAV or TAV (P ancova=0.82). However, in women MG was higher in those with BAV versus those with TAV (P ancova=0.04) (Figure). After adjusting for AVCd, the aortic valve morphology did not correlate with MG in men (p=0.82) whereas it did in women (p=0.04). For the same burden of valve calcification, MG was higher in women with BAV compared to those with TAV, while there was no difference between BAV and TAV among men. Thus, AVCd assessed by computed tomography may underestimate AS severity in women with BAV and should then be interpreted cautiously. Further studies are needed to better determine the mechanisms underlying this sex-related difference between BAV and TAV aortic stenosis.

Lipoprotein(a) (Lp[a]) is one of the strongest genetic risk factor for coronary artery disease (CAD). Although the variation in plasma Lp(a) levels has been shown to be strongly influenced by genetics, whether Lp(a) is associated with an altered cardiometabolic risk profile and whether lifestyle changes could improve Lp(a) levels in patients with CAD is unknown. The aim of the study was to determine if patients with high Lp(a) levels were characterized by a deteriorated cardiometabolic risk profile and whether a 1-year lifestyle modification program aiming at increasing physical activity levels and improve diet quality could decrease Lp(a) levels in post coronary artery bypass graft (CABG) patients.

The IMPACT-CABG trial (NCT01033617) is a Canadian multicenter randomized, prospective, double-blinded study investigating the feasibility, safety and efficacy of intramyocardial injections of autologous CD133+ stem cells in patients with chronic ischemic cardiomyopathy and impaired LV dysfunction (LVEF 25-45%) undergoing isolated CABG surgery. The primary safety endpoint was freedom from major adverse cardiac event (MACE) at time of injection and 6 months follow-up, including freedom from cardiac death, myocardial infarction (MI), repeat revascularization or severe arrhythmias. The secondary efficacy endpoint was regional myocardial perfusion and function assessed by magnetic resonance imaging (MRI). Herein we are reporting the safety results. After an initial 5 (Montréal) or 2 (Toronto) open-label patients who received stem cells, patients were then randomized in a 1:1 (Toronto=18) or 2:1 (Montréal=15) ratio to receive either stem cells or placebo. All forty patients (20 each in Montréal and Toronto) with ischemic cardiomyopathy and clinical indications for CABG provided informed consent and were assessed with preoperative stress echo and perfusion MRI. All patients had 100-150 cc of bone marrow aspirated from the iliac crest under local anaesthesia and light sedation on the morning of surgery. Stem cells were isolated using the CliniMACS® CD133+ Reagent System (Miltenyi Biotec), which utilizes super-paramagnetic beads composed of iron-dextran particles conjugated to monoclonal antibodies. On the afternoon following cell preparation, patients underwent conventional CABG surgery under cardiopulmonary bypass. Following the completion of the distal coronary anastomoses, the cell preparation containing up to 10 million cells or placebo was injected (10-15 injection sites) into the infarct and border zone as identified by MRI. Patient demographics, intraoperative data and hospital outcomes are presented in Table 1 for all 40 patients. Stem cell isolation procedures yielded cell preparations meeting release criteria in all patients randomized to cell delivery. There was no in-hospital mortality. No patient had a perioperative MI, 4 had renal failure, one had a wound infection and one had a seizure. During the 6-month follow-up period, one patient died from a pulmonary embolus, and no other MACE. This work represents the first Canadian experience with CD133+ stem cells for the treatment of chronic ischemic cardiomyopathy. There were no protocol-related complications, demonstrating that same-day isolation and delivery of stem cells in conjunction with CABG is safe and feasible. Cell therapy may become a valuable adjunct treatment for myocardial repair in heart failure patients in whom conventional therapies for ventricular dysfunction are limited.

Up to 30% of the patients with aortic stenosis (AS) and preserved LV ejection fraction (LVEF) have a discrepancy among the echocardiographic parameters of stenosis severity, the most frequent being an aortic valve area (AVA) < 1.0 cm2 consistent with severe stenosis and mean gradient (MG) < 40 mm Hg consistent with non-severe stenosis. Measurement of aortic valve calcification (AVC) by computed tomography (CT) correlates well with echocardiographic parameters of AS severity and it has been shown to be useful to corroborate stenosis severity in patients with discordant grading at echocardiography. However, the impact of the aortic valve phenotype (i.e. bicuspid vs. tricuspid) on this relationship between AVC and hemodynamic severity of AS remains unknown. The aims of this study were to evaluate relationship and concordance between echocardiographic and CT parameters of AS severity, with respect to aortic valve phenotype. 188 patients with AS and preserved LVEF were prospectively recruited in the PROGRESSA study (Clinical Trial register: NCT01679431) and underwent a comprehensive Doppler-echocardiography and CT scan. Echocardiographic parameters of AS severity included MG, AVA and indexed AVA (AVAi). AVC was determined by the Agatston method and indexed to the LV outflow tract area (i.e. AVC density: AVCd). The stenosis was considered severe when AVCd was ≥300 AU/cm2 in women and ≥500 AU/cm2 in men as previously described. AVCd correlated well with the echocardiographic parameters of stenosis severity (r>0.53; p<0.0001) in the patients with tricuspid valve but there was no significant correlation in the patients with a bicuspid valve (r<0.14; p>0.40). Of note, 5 of the 38 patients (13%) with a bicuspid valve had very low AVCd (<4 AU/cm2) despite the presence of at least moderate AS on echocardiography confirmed by several parameters including the gradient (MG>20mmHg). Although AVC measured by CT may be useful to corroborate stenosis severity in patients with discordant echocardiographic findings, this parameter should be used with caution in patients with a bicuspid valve given that it may yield to false negative result in about 10-15% of the cases.

Aortic stenosis (AS) severity contributes to the left ventricle (LV) deterioration due to the aortic valve narrowing and the alteration of systemic hemodynamic load. This load increment may also increase the LV stroke work (SW) which represent the required energy to deliver the blood at ejection. In this study, SW was derived from in-vivo cardiovascular magnetic resonance (CMR) velocity measurements (n=57) using a lumped-parametric model. Furthermore, normalized SW (N-SW) was evaluated as AS severity parameter. SW differentiated from normal flow (>35 mL/m(2)) and low flow (<35 mL/m(2)) states (p<0.05). N-SW showed a good association with valve effective orifice area (EOA, r=-0.5, p<0.001) and valvulo-arterial impedance (ZVA, r=0.65, p<0.001). A severity threshold for N-SW (1.5 cJ/mL) was found using an EOA=1 cm(2) as AS severity marker. CMR-derived SW and N-SW may be useful to the assessment and grading of AS patients.

Background: Bioprosthetic valves (BPVs) are specifically recommended in patients older than 65 years because of their limited durability mainly due to progressive leaflet calcification with a reoperation rate for structural degeneration of 30% at 15 years. Recent data highlight that BPV calcification is an active rather than passive process probably modulated by several mechanisms including dysfunctional calcium-related metabolism. The objective of this prospective study was to identify the clinical and metabolic determinants of bioprosthetic calcification assessed by multi-detector computed tomography (CT). Methods and results: One hundred and ninety-four (194) consecutive patients (pts) with an aortic BPV were recruited and underwent a CT for BPV calcification assessment. A calcification score was individually calculated using the volumetric method and expressed in mm3. Patients also underwent a clinical evaluation with a detailed record of medications, a Doppler-echocardiographic exam and a complete plasma phospho-calcic profile. Forty-six (46) pts (24%) had a calcification score above zero mm3 and represented the BPV calcification group. Patients with BPV calcification had higher plasma levels of calcium (2.37±0.01mmol/l vs. 2.34±0.07mmol/l, p=0.1), higher plasma levels of phosphorus (1.06±0.15mmol/l vs. 1.02±0.15 mmol/l, p=0.1) and a significant higher calcium phosphorus product (2.55±0.36 mmol2/l2 vs. 2.41±0.39 mmol2/l2, p=0.04). On multivariate analysis, increased calcium phosphorus product (Odds ratio [OR]=1.11, 95% confidence interval [CI]: 1.01-1.23 p=0.02) and the presence of patient-prosthesis mismatch (OR=3.67, 95% CI: 1.25-10.6 p=0.01) were the strongest independent predictors of BPV calcification. Calcium supplement intake, age and female gender were independently associated with increased calcium phosphorus product. Conclusion: This study demonstrates a strong independent association between higher calcium phosphorus product and increased risk of BPV calcification assessed by CT. Furthermore, this study reports that calcium supplements which are extensively prescribed in elderly patients are independently associated with higher calcium phosphorus product. The influence of calcium supplementation on bioprosthetic valve calcification needs further studies to be clearly investigated because it may have important therapeutic implications.

Vorticity and vortical structures play a fundamental role affecting the evaluation of energetic aspects (mainly left ventricle work) of cardiovascular function. Vorticity can be derived from cardiovascular magnetic resonance (CMR) imaging velocity measurements. However, several numerical schemes can be used to evaluate the vorticity field. The main objective of this work is to assess different numerical schemes used to evaluate the vorticity field derived from CMR velocity measurements. We compared the vorticity field obtained using direct differentiation schemes (eight-point circulation and Chapra) and derivate differentiation schemes (Richardson 4* and compact Richardson 4*) from a theoretical velocity field and in vivo CMR velocity measurements. In all cases, the effect of artificial spatial resolution up-sampling and signal-to-noise ratio (SNR) on vorticity computation was evaluated. Theoretical and in vivo results showed that the eight-point circulation method underestimated vorticity. Up-sampling evaluation showed that the artificial improvement of spatial resolution had no effect on mean absolute vorticity estimation but it affected SNR for all methods. The Richardson 4* method and its compact version were the most accurate and stable methods for vorticity magnitude evaluation. Vorticity field determination using the eight-point circulation method, the most common method used in CMR, has reduced accuracy compared to other vorticity schemes. Richardson 4* and its compact version showed stable SNR using both theoretical and in vivo data.

Given its anatomical contiguity to the heart, epicardial adipose tissue (EAT) has been suggested to directly impact the coronary arteries as a source of bioactive mediators of inflammation and atherosclerosis. As several studies have indicated a relationship between EAT and chronic coronary atherosclerosis, we questioned whether EAT also predicted cardiovascular events. The aim of this study was to determine the association between EAT, markers of cardiovascular risk, and recurrent major adverse cardiovascular events (MACE) in patients presenting with a successfully revascularized first ST-elevation myocardial infarction (STEMI).

Previous studies reported a good agreement between cardiovascular magnetic resonance (CMR) and transthoracic echocardiography (TTE) for the assessment of the effective orifice area (EOA) of native aortic valves. The objective of this study was to compare CMR and TTE for the estimation of the EOA of aortic bileaflet mechanical valves (BMV).