Left ventricular remodeling in heart failure: current concepts in clinical significance and assessment

Histological Quantification of Chronic Myocardial Infarct in Rats

Myocardial infarction is defined as cardiomyocyte death due to prolonged ischemia; an inflammatory response and scar formation (fibrosis) follow the ischemic injury. Following the initial acute phase, chronic remodeling of the left ventricle (LV) modifies the structure and function of the heart. Permanent coronary ligation in small animals has been widely used as a reference model for a chronic model of MI. Thinning of the infarcted wall progressively develops to transmural fibrosis. Histological assessment of infarct size is commonly performed; nevertheless, a standardization of the methods for quantification is missing. Indeed, important methodological aspects, such as the number of sections analyzed and the sampling and quantification methods, are usually not described and therefore preclude comparison across investigations. Too often, quantification is performed on a single section obtained at the level of the papillary muscles. Because novel strategies aimed at reducing infarct expansion and remodeling are under investigation, there is an important need for the standardization of accurate heart sampling protocols. We describe an accurate method to quantify the infarct size using a systematic sampling of harvested rat heart and image analyses of trichromatic stained histological sections obtained from base to apex. We also provide evidence that calculating the expansion index (EI) allowed for infarct size assessment, taking into account changes of the left ventricle throughout the remodeling.

Inhibition of Interleukin-6 Receptor in a Murine Model of Myocardial Ischemia-Reperfusion

Background

Interleukin-6 (IL-6) levels are upregulated in myocardial infarction. Recent data suggest a causal role of the IL-6 receptor (IL-6R) in coronary heart disease. We evaluated if IL-6R blockade by a monoclonal antibody (MR16-1) prevents the heart from adverse left ventricular remodeling in a mouse model of ischemia-reperfusion (I/R).

Methods

CJ57/BL6 mice underwent I/R injury (left coronary artery ligation for 45 minutes) or sham surgery, and thereafter received MR16-1 (2mg/mouse) 5 minutes before reperfusion and 0.5mg/mouse weekly during four weeks, or control IgG treatment. Cardiac Magnetic Resonance Imaging (CMR) and hemodynamic measurements were performed to determine cardiac function after four weeks.

Results

I/R caused left ventricular dilatation and a decrease in left ventricular ejection fraction (LVEF). However, LVEF was significantly lower in the MR16-1 treatment group compared to the IgG group (28±4% vs. 35±6%, p = 0.02; sham 45±6% vs. 43±4%, respectively; p = NS). Cardiac relaxation (assessed by dP/dT) was not significantly different between the MR16-1 and IgG groups. Also, no differences were observed in histological myocardial fibrosis, infarct size and myocyte hypertrophy between the groups.

Conclusion

Blockade of the IL-6R receptor by the monoclonal MR16-1 antibody for four weeks started directly after I/R injury did not prevent the process of cardiac remodeling in mice, but rather associated with a deterioration in the process of adverse cardiac remodeling.

Prognostic value of CT-derived left atrial and left ventricular measures in patients with acute chest pain

PURPOSE

To determine which left atrial (LA) and left ventricular (LV) parameters are associated with future major adverse cardiac event (MACE) and whether these measurements have independent prognostic value beyond risk factors and computed tomography (CT)-derived coronary artery disease measures.

MATERIALS AND METHODS

This retrospective analysis was performed under an IRB waiver and in HIPAA compliance. Subjects underwent coronary CT angiography (CCTA) using a dual-source CT system for acute chest pain evaluation. LV mass, LV ejection fraction (EF), LV end-systolic volume (ESV) and LV end-diastolic volume (EDV), LA ESV and LA diameter, septal wall thickness and cardiac chamber diameters were measured. MACE was defined as cardiac death, non-fatal myocardial infarction, unstable angina, or late revascularization. The association between cardiac CT measures and the occurrence of MACE was quantified using Cox proportional hazard analysis.

RESULTS

225 subjects (age, 56.2±11.2; 140 males) were analyzed, of whom 42 (18.7%) experienced a MACE during a median follow-up of 13 months. LA diameter (HR:1.07, 95%CI:1.01-1.13permm) and LV mass (HR:1.05, 95%CI:1.00-1.10perg) remained significant prognostic factor of MACE after controlling for Framingham risk score. LA diameter and LV mass were also found to have prognostic value independent of each other. The other morphologic and functional cardiac measures were no significant prognostic factors for MACE.

CONCLUSION

CT-derived LA diameter and LV mass are associated with future MACE in patients undergoing evaluation for chest pain, and portend independent prognostic value beyond traditional risk factors, coronary calcium score, and obstructive coronary artery disease.

Relevance of mouse models of cardiac fibrosis and hypertrophy in cardiac research

Heart disease causing cardiac cell death due to ischemia-reperfusion injury is a major cause of morbidity and mortality in the United States. Coronary heart disease and cardiomyopathies are the major cause for congestive heart failure, and thrombosis of the coronary arteries is the most common cause of myocardial infarction. Cardiac injury is followed by post-injury cardiac remodeling or fibrosis. Cardiac fibrosis is characterized by net accumulation of extracellular matrix proteins in the cardiac interstitium and results in both systolic and diastolic dysfunctions. It has been suggested by both experimental and clinical evidence that fibrotic changes in the heart are reversible. Hence, it is vital to understand the mechanism involved in the initiation, progression, and resolution of cardiac fibrosis to design anti-fibrotic treatment modalities. Animal models are of great importance for cardiovascular research studies. With the developing research field, the choice of selecting an animal model for the proposed research study is crucial for its outcome and translational purpose. Compared to large animal models for cardiac research, the mouse model is preferred by many investigators because of genetic manipulations and easier handling. This critical review is focused to provide insight to young researchers about the various mouse models, advantages and disadvantages, and their use in research pertaining to cardiac fibrosis and hypertrophy.

Oxidative Stress and Salvia miltiorrhiza in Aging-Associated Cardiovascular Diseases

Aging-associated cardiovascular diseases (CVDs) have some risk factors that are closely related to oxidative stress. Salvia miltiorrhiza (SM) has been used commonly to treat CVDs for hundreds of years in the Chinese community. We aimed to explore the effects of SM on oxidative stress in aging-associated CVDs. Through literature searches using Medicine, PubMed, EMBASE, Cochrane library, CINAHL, and Scopus databases, we found that SM not only possesses antioxidant, antiapoptotic, and anti-inflammatory effects but also exerts angiogenic and cardioprotective activities. SM may reduce the production of reactive oxygen species by inhibiting oxidases, reducing the production of superoxide, inhibiting the oxidative modification of low-density lipoproteins, and ameliorating mitochondrial oxidative stress. SM also increases the activities of catalase, manganese superoxide dismutase, glutathione peroxidase, and coupled endothelial nitric oxide synthase. In addition, SM reduces the impact of ischemia/reperfusion injury, prevents cardiac fibrosis after myocardial infarction, preserves cardiac function in coronary disease, maintains the integrity of the blood-brain barrier, and promotes self-renewal and proliferation of neural stem/progenitor cells in stroke. However, future clinical well-designed and randomized control trials will be necessary to confirm the efficacy of SM in aging-associated CVDs.

Rationale and design of the Children's Oncology Group (COG) study ALTE1621: a randomized, placebo-controlled trial to determine if low-dose carvedilol can prevent anthracycline-related left ventricular remodeling in childhood cancer survivors at high risk for developing heart failure

BACKGROUND

Anthracyclines are widely used in the treatment of childhood cancer. One of the well-recognized side-effects of anthracycline therapy is dose-dependent cardiomyopathy that may progress to heart failure (HF) years after completion of cancer-directed therapy. This study will evaluate the efficacy of low-dose beta-blocker (carvedilol) for HF risk reduction in childhood cancer survivors at highest risk for HF. The proposed intervention has the potential to significantly reduce chronic cardiac injury via interruption of neurohormonal systems responsible for left ventricular (LV) remodeling, resulting in improved cardiac function and decreased risk of HF. The intervention is informed by previous studies demonstrating efficacy in pediatric and adult non-oncology populations, yet remains unstudied in the pediatric oncology population.

METHODS/DESIGN

The primary objective of the trial is to determine impact of the intervention on echocardiographic markers of cardiac remodeling and HF risk, including: LV wall thickness/ dimension ratio (LVWT/D; primary endpoint), as well as LV ejection fraction, volume, and blood biomarkers (natriuretic peptides, galectin-3) associated with HF risk. Secondary objectives are to establish safety and tolerability of the 2-year course of carvedilol using: 1) objective measures: hepatic and cardiovascular toxicity, treatment adherence, and 2) subjective measures: participant self-reported outcomes. Two hundred and fifty survivors of childhood cancer (diagnosed <21 years of age), and previously treated with high-dose (≥300 mg/m2) anthracyclines will be enrolled in a randomized, double-blind, placebo controlled trial. After baseline assessments, participants will be randomized in a 1:1 ratio to low-dose carvedilol (maximum dose: 12.5 mg/day) or placebo. Carvedilol or placebo is up-titrated (starting dose: 3.125 mg/day) according to tolerability.

DISCUSSION

When completed, this study will provide much-needed information regarding a physiologically plausible pharmacological risk-reduction strategy for childhood cancer survivors at high risk for developing anthracycline-related HF.

TRIAL REGISTRATION

ClinicalTrials.gov; NCT02717507.

Changes in Left Ventricular Ejection Fraction Predict Survival and Hospitalization in Heart Failure With Reduced Ejection Fraction

BACKGROUND

Left ventricular remodeling, as commonly measured by left ventricular ejection fraction (LVEF), is associated with clinical outcomes. Although change in LVEF over time should reflect response to therapy and clinical course, serial measurement of LVEF is inconsistently performed in observational settings, and the incremental prognostic value of change in LVEF has not been well characterized.

METHODS AND RESULTS

The β-Blocker Evaluation of Survival Trial measured LVEF by radionuclide ventriculography at baseline and at 3 and 12 months after randomization. We built a series of multivariable models with 16 clinical parameters plus change in LVEF for predicting 4 major clinical end points, including the trial's primary end point of all-cause mortality. Among 2484 patients with at least 1 follow-up LVEF, change in LVEF was the second most significant predictor (behind baseline creatinine) of all-cause mortality (adjusted hazard ratio for improvement in LVEF by ≥5 U responder versus nonresponder [95% confidence intervals] for all-cause mortality=0.62 [0.52-0.73]). Other end points, including heart failure hospitalization or the composite of all-cause mortality and heart failure hospitalization, yielded similar results. LVEF change ≥5 U was associated with a modest increase in discrimination when added to traditional predictors and was predictive of outcomes in both the bucindolol and placebo treatment groups. LVEF change as a predictor of outcomes was affected by sex and race, with evidence that LVEF improvement is associated with less survival benefit in African Americans and women.

CONCLUSIONS

Serial evaluation for LVEF change predicts both survival and heart failure hospitalization and provides a dynamic/real-time measure of prognosis in heart failure with reduced LVEF.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00000560.

Infarct Localization From Myocardial Deformation: Prediction and Uncertainty Quantification by Regression From a Low-Dimensional Space

Diagnosing and localizing myocardial infarct is crucial for early patient management and therapy planning. We propose a new method for predicting the location of myocardial infarct from local wall deformation, which has value for risk stratification from routine examinations such as (3D) echocardiography. The pipeline combines non-linear dimensionality reduction of deformation patterns and two multi-scale kernel regressions. Confidence in the diagnosis is assessed by a map of local uncertainties, which integrates plausible infarct locations generated from the space of reduced dimensionality. These concepts were tested on 500 synthetic cases generated from a realistic cardiac electromechanical model, and 108 pairs of 3D echocardiographic sequences and delayed-enhancement magnetic resonance images from real cases. Infarct prediction is made at a spatial resolution around 4 mm, more than 10 times smaller than the current diagnosis, made regionally. Our method is accurate, and significantly outperforms the clinically-used thresholding of the deformation patterns (on real data: sensitivity/specificity of 0.828/0.804, area under the curve: 0.909 versus 0.742 for the most predictive strain component). Uncertainty adds value to refine the diagnosis and eventually re-examine suspicious cases.

Early-stage heart failure with preserved ejection fraction in the pig: a cardiovascular magnetic resonance study

BACKGROUND

The hypertensive deoxy-corticosterone acetate (DOCA)-salt-treated pig (hereafter, DOCA pig) was recently introduced as large animal model for early-stage heart failure with preserved ejection fraction (HFpEF). The aim of the present study was to evaluate cardiovascular magnetic resonance (CMR) of DOCA pigs and weight-matched control pigs to characterize ventricular, atrial and myocardial structure and function of this phenotype model.

METHODS

Five anesthetized DOCA and seven control pigs underwent 3 T CMR at rest and during dobutamine stress. Left ventricular/atrial (LV/LA) function and myocardial mass (LVMM), strains and torsion were evaluated from (tagged) cine imaging. 4D phase-contrast measurements were used to assess blood flow and peak velocities, including transmitral early-diastolic (E) and myocardial tissue (E') velocities and coronary sinus blood flow. Myocardial perfusion reserve was estimated from stress-to-rest time-averaged coronary sinus flow. Global native myocardial T1 times were derived from prototype modified Look-Locker inversion-recovery (MOLLI) short-axis T1 maps. After in-vivo measurements, transmural biopsies were collected for stereological evaluation including the volume fractions of interstitium (V_V(int/LV)) and collagen (V_V(coll/LV)). Rest, stress, and stress-to-rest differences of cardiac and myocardial parameters in DOCA and control animals were compared by t-test.

RESULTS

In DOCA pigs LVMM (p < 0.001) and LV wall-thickness (end-systole/end-diastole, p = 0.003/p = 0.007) were elevated. During stress, increase of LV ejection-fraction and decrease of end-systolic volume accounted for normal contractility reserves in DOCA and control pigs. Rest-to-stress differences of cardiac index (p = 0.040) and end-diastolic volume (p = 0.042) were documented. Maximal (p = 0.042) and minimal (p = 0.012) LA volumes in DOCA pigs were elevated at rest; total LA ejection-fraction decreased during stress (p = 0.006). E' was lower in DOCA pigs, corresponding to higher E/E' at rest (p = 0.013) and stress (p = 0.026). Myocardial perfusion reserve was reduced in DOCA pigs (p = 0.031). T1-times and V_V(int/LV) did not differ between groups, whereas V_V(coll/LV) levels were higher in DOCA pigs (p = 0.044).

CONCLUSIONS

LA enlargement, E' and E/E' were the markers that showed the most pronounced differences between DOCA and control pigs at rest. Inadequate increase of myocardial perfusion reserve during stress might represent a metrics for early-stage HFpEF. Myocardial T1 mapping could not detect elevated levels of myocardial collagen in this model.

TRIAL REGISTRATION

The study was approved by the local Bioethics Committee of Vienna, Austria (BMWF-66.010/0091-II/3b/2013).

Early-stage heart failure with preserved ejection fraction in the pig: a cardiovascular magnetic resonance study

BACKGROUND

The hypertensive deoxy-corticosterone acetate (DOCA)-salt-treated pig (hereafter, DOCA pig) was recently introduced as large animal model for early-stage heart failure with preserved ejection fraction (HFpEF). The aim of the present study was to evaluate cardiovascular magnetic resonance (CMR) of DOCA pigs and weight-matched control pigs to characterize ventricular, atrial and myocardial structure and function of this phenotype model.

METHODS

Five anesthetized DOCA and seven control pigs underwent 3 T CMR at rest and during dobutamine stress. Left ventricular/atrial (LV/LA) function and myocardial mass (LVMM), strains and torsion were evaluated from (tagged) cine imaging. 4D phase-contrast measurements were used to assess blood flow and peak velocities, including transmitral early-diastolic (E) and myocardial tissue (E') velocities and coronary sinus blood flow. Myocardial perfusion reserve was estimated from stress-to-rest time-averaged coronary sinus flow. Global native myocardial T1 times were derived from prototype modified Look-Locker inversion-recovery (MOLLI) short-axis T1 maps. After in-vivo measurements, transmural biopsies were collected for stereological evaluation including the volume fractions of interstitium (VV(int/LV)) and collagen (VV(coll/LV)). Rest, stress, and stress-to-rest differences of cardiac and myocardial parameters in DOCA and control animals were compared by t-test.

RESULTS

In DOCA pigs LVMM (p < 0.001) and LV wall-thickness (end-systole/end-diastole, p = 0.003/p = 0.007) were elevated. During stress, increase of LV ejection-fraction and decrease of end-systolic volume accounted for normal contractility reserves in DOCA and control pigs. Rest-to-stress differences of cardiac index (p = 0.040) and end-diastolic volume (p = 0.042) were documented. Maximal (p = 0.042) and minimal (p = 0.012) LA volumes in DOCA pigs were elevated at rest; total LA ejection-fraction decreased during stress (p = 0.006). E' was lower in DOCA pigs, corresponding to higher E/E' at rest (p = 0.013) and stress (p = 0.026). Myocardial perfusion reserve was reduced in DOCA pigs (p = 0.031). T1-times and VV(int/LV) did not differ between groups, whereas VV(coll/LV) levels were higher in DOCA pigs (p = 0.044).

CONCLUSIONS

LA enlargement, E' and E/E' were the markers that showed the most pronounced differences between DOCA and control pigs at rest. Inadequate increase of myocardial perfusion reserve during stress might represent a metrics for early-stage HFpEF. Myocardial T1 mapping could not detect elevated levels of myocardial collagen in this model.

TRIAL REGISTRATION

The study was approved by the local Bioethics Committee of Vienna, Austria (BMWF-66.010/0091-II/3b/2013).

Spacial and Temporal Patterns of Gene Expression After Cardiac MEK1 Gene Transfer Improve Post-Infarction Remodeling Without Inducing Global Hypertrophy

Alteration of mitogen activated protein (MAP) kinase signaling in transgenic mice can ameliorate post-myocardial infarction (MI) remodeling. However, pre-existing changes in transgenic hearts and clinically unrealistic transgene expression likely affect the response to injury; it is unknown whether clinically relevant induction of transgene expression in an otherwise normal heart can yield similar benefits. Constitutively active MEK1 (aMEK1) or LacZ adeno-associated virus 9 (AAV9) vectors were injected into the left ventricular (LV) chambers of mice either just before or after coronary ligation. Hearts were evaluated via Western blot, quantitative polymerase chain reaction, histology, and echocardiography. AAV9-mediated aMEK1 delivery altered ERK1/2 expression/activation as in transgenic mice. Transgene expression was not immediately detectable but plateaued at 17 days, and therefore did not likely impact acute ischemia as it would in transgenics. With AAV9-aMEK1 injection just prior to MI, robust expression in the infarct border zone during post-MI remodeling increased border zone wall thickness and reduced infarct size versus controls at 4 weeks, but did not induce global hypertrophy. Significant improvements in local and global LV function were observed, as were trends toward a preservation of LV volume. Delivery after ligation significantly lowered transgene expression in the infarct border zone and did not yield structural or functional benefits. The primary benefits observed in transgenic mice, ameliorated remodeling, and reduced chronic infarct size, were achievable via clinically relevant gene transfer of aMEK1, supporting ongoing translational efforts. Important differences, however, were observed, and consideration must be given to the timing and distribution of transgene delivery and expression. J. Cell. Biochem. 118: 775-784, 2017. © 2016 Wiley Periodicals, Inc.

Regulation of Cardiac Remodeling by Cardiac Na(+)/K(+)-ATPase Isoforms

Cardiac remodeling occurs after cardiac pressure/volume overload or myocardial injury during the development of heart failure and is a determinant of heart failure. Preventing or reversing remodeling is a goal of heart failure therapy. Human cardiomyocyte Na⁺/K⁺-ATPase has multiple α isoforms (1–3). The expression of the α subunit of the Na⁺/K⁺-ATPase is often altered in hypertrophic and failing hearts. The mechanisms are unclear. There are limited data from human cardiomyocytes. Abundant evidences from rodents show that Na⁺/K⁺-ATPase regulates cardiac contractility, cell signaling, hypertrophy and fibrosis. The α1 isoform of the Na⁺/K⁺-ATPase is the ubiquitous isoform and possesses both pumping and signaling functions. The α2 isoform of the Na⁺/K⁺-ATPase regulates intracellular Ca²⁺ signaling, contractility and pathological hypertrophy. The α3 isoform of the Na⁺/K⁺-ATPase may also be a target for cardiac hypertrophy. Restoration of cardiac Na⁺/K⁺-ATPase expression may be an effective approach for prevention of cardiac remodeling. In this article, we will overview: (1) the distribution and function of isoform specific Na⁺/K⁺-ATPase in the cardiomyocytes. (2) the role of cardiac Na⁺/K⁺-ATPase in the regulation of cell signaling, contractility, cardiac hypertrophy and fibrosis in vitro and in vivo. Selective targeting of cardiac Na⁺/K⁺-ATPase isoform may offer a new target for the prevention of cardiac remodeling.

Cardiac DPP-4 inhibition by saxagliptin ameliorates isoproterenol-induced myocardial remodeling and cardiac diastolic dysfunction in rats

Saxagliptin, a potent and selective DPP-4 inhibitor, is characterized by its slow dissociation from DPP-4 and its long half-life and is expected to have a potent tissue membrane-bound DPP-4-inhibitory effect in various tissues. In the present study, we examined the effects of saxagliptin on in situ cardiac DPP-4 activity. We also examined the effects of saxagliptin on isoproterenol-induced the changes in the early stage such as, myocardial remodeling and cardiac diastolic dysfunction. Male SD rats treated with isoproterenol (1 mg/kg/day via osmotic pump) received vehicle or saxagliptin (17.5 mg/kg via drinking water) for 2 weeks. In situ cardiac DPP-4 activity was measured by a colorimetric assay. Cardiac gene expressions were examined and an echocardiographic analysis was performed. Saxagliptin treatment significantly inhibited in situ cardiac DPP-4 activity and suppressed isoproterenol-induced myocardial remodeling and the expression of related genes without altering the blood glucose levels. Saxagliptin also significantly ameliorated cardiac diastolic dysfunction in isoproterenol-treated rats. In conclusion, the inhibition of DPP-4 activity in cardiac tissue by saxagliptin was associated with suppression of myocardial remodeling and cardiac diastolic dysfunction independently of its glucose-lowering action in isoproterenol-treated rats. Cardiac DPP-4 activity may contribute to myocardial remodeling in the development of heart failure.

Current Perspectives on Left Ventricular Geometry in Systemic Hypertension

Hypertension (HTN) is a global health problem and a leading risk factor for cardiovascular disease (CVD) morbidity and mortality. The hemodynamic overload from HTN causes left ventricular (LV) remodeling, which usually manifests as distinct alterations in LV geometry, such as concentric remodeling or concentric and eccentric LV hypertrophy (LVH). In addition to being a common target organ response to HTN, LV geometric abnormalities are well-known independent risk factors for CVD. Because of their prognostic implications and quantifiable nature, changes in LV geometric parameters have commonly been included as an outcome in anti-HTN drug trials. The purpose of this paper is to review the relationship between HTN and LV geometric changes with a focus on (1) diagnostic approach, (2) epidemiology, (3) pathophysiology, (4) prognostic effect and (5) LV response to anti-HTN therapy and its impact on CVD risk reduction.

Three-dimensional maximum principal strain using cardiac computed tomography for identification of myocardial infarction

OBJECTIVES

To evaluate the feasibility of three-dimensional (3D) maximum principal strain (MP-strain) derived from cardiac computed tomography (CT) for detecting myocardial infarction (MI).

METHODS

Forty-three patients who underwent cardiac CT and magnetic resonance imaging (MRI) were retrospectively selected. Using the voxel tracking of motion coherence algorithm, the peak CT MP-strain was measured using the 16-segment model. With the trans-mural extent of late gadolinium enhancement (LGE) and the distance from MI, all segments were classified into four groups (infarcted, border, adjacent, and remote segments); infarcted and border segments were defined as MI with LGE positive. Diagnostic performance of MP-strain for detecting MI was compared with per cent systolic wall thickening (%SWT) assessed by MRI using receiver-operating characteristic curve analysis at a segment level.

RESULTS

Of 672 segments excluding16 segments influenced by artefacts, 193 were diagnosed as MI. Sensitivity and specificity of peak MP-strain to identify MI were 81 % [95 % confidence interval (95 % CI): 74-88 %] and 86 % (81-92 %) compared with %SWT: 76 % (60-95 %) and 68 % (48-84 %), respectively. The area under the curve of peak MP-strain was superior to %SWT [0.90 (0.87-0.93) vs. 0.80 (0.76-0.83), p < 0.05].

CONCLUSIONS

CT MP-strain has a potential to provide incremental value to coronary CT angiography for detecting MI.

KEY POINTS

• CT MP-strain allows for three-dimensional assessment of regional cardiac function. • CT-MP strain has high diagnostic accuracy for detecting myocardial infarction. • CT-MP strain may assist in tissue characterisation of myocardium assessed by LGE-MRI. • CT-MP strain provides incremental values to coronary CTA for detecting myocardial infarction.

Percutaneous ventricular restoration (PVR) therapy using the Parachute device in 100 subjects with ischaemic dilated heart failure: one-year primary endpoint results of PARACHUTE III, a European trial

AIMS

This prospective, non-randomised, observational study conducted in Europe was designed in order to assess the long-term safety and efficacy of the Parachute device in ischaemic heart failure subjects as a result of left ventricle remodelling after anterior wall myocardial infarction.

METHODS AND RESULTS

One hundred subjects with New York Heart Association Class II-IV ischaemic heart failure (HF), ejection fraction (EF) between 15% and 40%, and dilated akinetic or dyskinetic anterior-apical wall without the need to be revascularised were enrolled. The primary safety endpoint was procedural- or device-related major adverse cardiac cerebral events (MACCE). The secondary safety endpoint was the composite of mortality and morbidity. Secondary efficacy endpoints included haemodynamic measurements determined by echocardiography, LV volume indices, and assessment of functional improvement measured by a standardised six-minute walk test. Of the 100 subjects enrolled, device implantation was successful in 97 (97%) subjects. The one-year rates of the primary and secondary safety endpoints were 7% and 32.3%, respectively. The secondary endpoints, LV volume reduction (p<0.0001) and six-minute walk distance improvement (p<0.01), were achieved.

CONCLUSIONS

The favourable outcomes observed in this high-risk population provide reassuring safety and efficacy data to support adoption of this technology as a therapeutic option for HF subjects.

Macrophages in age-related chronic inflammatory diseases

Chronic inflammation is the common pathological basis for such age-associated diseases as cardiovascular disease, diabetes, cancer and Alzheimer’s disease. A multitude of bodily changes occur with aging that contribute to the initiation and development of inflammation. In particular, the immune system of elderly individuals often exhibits diminished efficiency and fidelity, termed immunosenescence. But, although immune responses to new pathogens and vaccines are impaired, immunosenescence is also characterized by a basal systemic inflammatory state. This alteration in immune system function likely promotes chronic inflammation. Changes in the tissue microenvironment, such as the accumulation of cell debris, and systemic changes in metabolic and hormonal signals, also likely contribute to the development of chronic inflammation. Monocyte/macrophage lineage cells are crucial to these age-associated changes, which culminate in the development of chronic inflammatory diseases. In this review, we will summarize the diverse physiological and pathological roles of macrophages in the chronic inflammation underlying age-associated diseases.

Galectin-3 predicts left ventricular remodelling after anterior-wall myocardial infarction treated by primary percutaneous coronary intervention

OBJECTIVES

Despite modern reperfusion therapies, left ventricular remodelling (LVR) occurs frequently after an ST-elevated myocardial infarction (STEMI) and represents a strong predictor of mortality and heart failure. Galectin-3 (Gal-3), a novel biomarker involved in inflammation, tissue repair and fibrogenesis, might be a valuable predictor of LVR.

METHODS

We enrolled consecutively admitted patients with a first anterior STEMI and left anterior descending artery occlusion treated by primary percutaneous coronary intervention (pPCI). Gal-3, N-terminal pro-B-type natriuretic peptide (NT-proBNP), echocardiography and cardiovascular events were evaluated 48 hours after admission, at 1 and 6 months. LVR was defined as a ≥15% increase in LV end-systolic volume.

RESULTS

We recruited 103 patients (28% women, aged 64.6±12 years, LV ejection fraction 47±11%). Median baseline Gal-3 and NT-proBNP levels were 13.2 ng/mL (10.8-17.1 ng/mL) and 2132 pg/mL (1019-4860 pg/mL) respectively. During 6 months of follow-up, 4 patients dropped out, 7 died and 26 (28.3%) of the 92 survivors developed LVR (LVR+). LVR+ patients had higher Gal-3 levels at baseline, 1 and 6 months than LVR- (p<0.0001). By univariable logistic regression, age, female gender, higher baseline Gal-3 and NT-proBNP, smaller LV end-diastolic volume (LVEDV) were associated to an increased risk of LVR. By multivariable analysis, only LVEDV (OR 0.96, 95% CI 0.93 to 0.99/1 mL change) and Gal-3 levels (OR 1.22, 95% CI 1.06 to 1.42/1 ng/mL change) independently predicted LVR (C-statistics 0.84, 95% CI 0.75 to 0.93).

CONCLUSION

Gal-3 serum levels measured during hospitalisation could be clinically useful in predicting LVR among patients admitted with anterior STEMI treated by pPCI.

Proliferation and Recruitment Contribute to Myocardial Macrophage Expansion in Chronic Heart Failure

RATIONALE

Macrophages reside in the healthy myocardium, participate in ischemic heart disease, and modulate myocardial infarction (MI) healing. Their origin and roles in post-MI remodeling of nonischemic remote myocardium, however, remain unclear.

OBJECTIVE

This study investigated the number, origin, phenotype, and function of remote cardiac macrophages residing in the nonischemic myocardium in mice with chronic heart failure after coronary ligation.

METHODS AND RESULTS

Eight weeks post MI, fate mapping and flow cytometry revealed that a 2.9-fold increase in remote macrophages results from both increased local macrophage proliferation and monocyte recruitment. Heart failure produced by extensive MI, through activation of the sympathetic nervous system, expanded medullary and extramedullary hematopoiesis. Circulating Ly6C(high) monocytes rose from 64±5 to 108±9 per microliter of blood (P<0.05). Cardiac monocyte recruitment declined in Ccr2(-/-) mice, reducing macrophage numbers in the failing myocardium. Mechanical strain of primary murine and human macrophage cultures promoted cell cycle entry, suggesting that the increased wall tension in post-MI heart failure stimulates local macrophage proliferation. Strained cells activated the mitogen-activated protein kinase pathway, whereas specific inhibitors of this pathway reduced macrophage proliferation in strained cell cultures and in the failing myocardium (P<0.05). Steady-state cardiac macrophages, monocyte-derived macrophages, and locally sourced macrophages isolated from failing myocardium expressed different genes in a pattern distinct from the M1/M2 macrophage polarization paradigm. In vivo silencing of endothelial cell adhesion molecules curbed post-MI monocyte recruitment to the remote myocardium and preserved ejection fraction (27.4±2.4 versus 19.1±2%; P<0.05).

CONCLUSIONS

Myocardial failure is influenced by an altered myeloid cell repertoire.

Research into the effect Of SGLT2 inhibition on left ventricular remodelling in patients with heart failure and diabetes mellitus (REFORM) trial rationale and design

Background

Heart failure (HF) and diabetes (DM) are a lethal combination. The current armamentarium of anti-diabetic agents has been shown to be less efficacious and sometimes even harmful in diabetic patients with concomitant cardiovascular disease, especially HF. Sodium glucose linked co-transporter type 2 (SGLT2) inhibitors are a new class of anti-diabetic agent that has shown potentially beneficial cardiovascular effects such as pre-load and after load reduction through osmotic diuresis, blood pressure reduction, reduced arterial stiffness and weight loss. This has been supported by the recently published EMPA-REG trial which showed a striking 38 and 35 % reduction in cardiovascular death and HF hospitalisation respectively.

Methods

The REFORM trial is a novel, phase IV randomised, double blind, placebo controlled clinical trial that has been ongoing since March 2015. It is designed specifically to test the safety and efficacy of the SLGT2 inhibitor, dapagliflozin, on diabetic patients with known HF. We utilise cardiac-MRI, cardio-pulmonary exercise testing, body composition analysis and other tests to quantify the cardiovascular and systemic effects of dapagliflozin 10 mg once daily against standard of care over a 1 year observation period. The primary outcome is to detect the change in left ventricular (LV) end systolic and LV end diastolic volumes. The secondary outcome measures include LV ejection fraction, LV mass index, exercise tolerance, fluid status, quality of life measures and others.

Conclusions

This trial will be able to determine if SGLT2 inhibitor therapy produces potentially beneficial effects in patients with DM and HF, thereby replacing current medications as the drug of choice when treating patients with both DM and HF.

Trial registration Clinical Trials.gov: NCT02397421. Registered 12th March 2015

Ataxia telangiectasia-mutated kinase deficiency exacerbates left ventricular dysfunction and remodeling late after myocardial infarction

Ataxia telangiectasia-mutated kinase (ATM), a cell cycle checkpoint protein, is activated in response to DNA damage and oxidative stress. We have previously shown that ATM deficiency is associated with increased apoptosis and fibrosis and attenuation of cardiac dysfunction early (1-7 days) following myocardial infarction (MI). Here, we tested the hypothesis that enhanced fibrosis and apoptosis, as observed early post-MI during ATM deficiency, exacerbate cardiac dysfunction and remodeling in ATM-deficient mice late post-MI. MIs were induced in wild-type (WT) and ATM heterozygous knockout (hKO) mice by ligation of the left anterior descending artery. Left ventricular (LV) structural and functional parameters were assessed by echocardiography 14 and 28 days post-MI, whereas biochemical parameters were measured 28 days post-MI. hKO-MI mice exhibited exacerbated LV dysfunction as observed by increased LV end-systolic volume and decreased percent fractional shortening and ejection fraction. Infarct size and thickness were not different between the two genotypes. Myocyte cross-sectional area was greater in hKO-MI group. The hKO-MI group exhibited increased fibrosis in the noninfarct and higher expression of α-smooth muscle actin (myofibroblast marker) in the infarct region. Apoptosis and activation of GSK-3β (proapoptotic kinase) were significantly lower in the infarct region of hKO-MI group. Matrix metalloproteinase 2 (MMP-2) expression was not different between the two genotypes. However, MMP-9 expression was significantly lower in the noninfarct region of hKO-MI group. Thus ATM deficiency exacerbates cardiac remodeling late post-MI with effects on cardiac function, fibrosis, apoptosis, and myocyte hypertrophy.

Arrhythmias and Electrocardiographic Changes in Systolic Heart Failure

Background:

Heart failure is a common condition that that leads to hospitalization. It is associated with various atrial and ventricular arrhythmias.

Aim:

The aim of this study is to find common arrhythmias and electrocardiographic changes in hospitalized patients who have systolic heart failure.

Materials and Methods:

This is a retrospective study of medical records, and electrocardiograms (EKGs) of 157 patients admitted to our hospital who had systolic heart failure with ejection fraction (EF) <50% on echocardiogram. Based on EF, the patients were divided into two groups; one with EF ≤ 35% and the other with EF > 35%. Twelve-lead EKG of these patients was studied to identify common arrhythmia and demographic variables; laboratory results were compared to identify the differences.

Results:

A total of 157 patients with systolic heart failure, 63.7% had an EF ≤ 35%. Hypertension 82.8%, diabetes 49%, coronary artery disease 40.8%, chronic obstructive pulmonary disease or bronchial asthma 22.3%, and stroke 12.1% were common associated co-morbidities. On analysis of EKG, 28.6% had tachycardia, 21.9% had prolonged PR > 200 ms, 16.3% had wide QRS > 120 ms, 70.7% had prolonged corrected QT (QTc), and 42.2% had left axis deviation. The most common arrhythmias were sinus tachycardia and atrial fibrillation/flutter which were found in 14.6% and 13.4%, respectively. The left ventricular hypertrophy was a common abnormality found in 22.4% followed by ventricular premature contractions 18.4%, atrial premature contractions 9.5%, and left bundle branch block 6.1%. Patients with severe systolic heart failure had prolonged QRS (P = 0.02) and prolonged QTc (P = 0.01) as compared to the other group.

Conclusions:

Sinus tachycardia and atrial fibrillation/flutter were common arrhythmias in patients with systolic heart failure. Patients with severe systolic heart failure had statistically significant prolongation of the QRS duration and QTc interval.

Image-Derived Assessment of Left Ventricular Mass in Fetal Myocardial Hypertrophy by 4-Dimensional Echocardiography: An In Vitro Study

OBJECTIVES

This study tested the accuracy of new 4-dimensional fetal echocardiography to evaluate left ventricular (LV) mass in an experimental model of fetal myocardial hypertrophy.

METHODS

Ten fresh rabbit hearts were studied. Fetal myocardial hypertrophy was simulated by fixing different amounts of myocardial tissue to the LV epicardium. A small latex balloon was mounted on vinyl tubing and fixed within each LV cavity. The proximal end of the tube was attached to a pulsatile pump apparatus. The pump was calibrated to deliver stroke volumes of 2 and 4 mL at stroke rates of 60 and 120 beats per minute (bpm). Four-dimensional data were acquired and analyzed with quantification software. Reference values for LV mass were determined by the displacement method.

RESULTS

Echo-derived measurements of LV mass showed good correlations with reference values at all stroke rates and stroke volumes: at 2 mL and 60 bpm, r = 0.95; at 2 mL and 120 bpm, r = 0.95; at 4 mL and 60 bpm, r = 0.93; and at 4 mL and 120 bpm, r = 0.95 (P< .01 for all values). There was also excellent interobserver (r = 0.98; mean difference of -0.32 g; -4.4% of the mean) and intraobserver (r = 0.98; mean difference of -0.28 g; -3.8% of the mean) agreement.

CONCLUSIONS

In this controlled in vitro study, high-resolution 4-dimensional echocardiography was shown to accurately assess LV mass and have the potential to evaluate fetal myocardial hypertrophy.

Matricellular Protein CCN5 Reverses Established Cardiac Fibrosis

BACKGROUND

Cardiac fibrosis (CF) is associated with increased ventricular stiffness and diastolic dysfunction and is an independent predictor of long-term clinical outcomes of patients with heart failure (HF). We previously showed that the matricellular CCN5 protein is cardioprotective via its ability to inhibit CF and preserve cardiac contractility.

OBJECTIVES

This study examined the role of CCN5 in human heart failure and tested whether CCN5 can reverse established CF in an experimental model of HF induced by pressure overload.

METHODS

Human hearts were obtained from patients with end-stage heart failure. Extensive CF was induced by applying transverse aortic constriction for 8 weeks, which was followed by adeno-associated virus-mediated transfer of CCN5 to the heart. Eight weeks following gene transfer, cellular and molecular effects were examined.

RESULTS

Expression of CCN5 was significantly decreased in failing hearts from patients with end-stage heart failure compared to nonfailing hearts. Trichrome staining and myofibroblast content measurements revealed that the established CF had been reversed by CCN5 gene transfer. Anti-CF effects of CCN5 were associated with inhibition of the transforming growth factor beta signaling pathway. CCN5 significantly inhibited endothelial-mesenchymal transition and fibroblast-to-myofibroblast transdifferentiation, which are 2 critical processes for CF progression, both in vivo and in vitro. In addition, CCN5 induced apoptosis in myofibroblasts, but not in cardiomyocytes or fibroblasts, both in vivo and in vitro. CCN5 provoked the intrinsic apoptotic pathway specifically in myofibroblasts, which may have been due the ability of CCN5 to inhibit the activity of NFκB, an antiapoptotic molecule.

CONCLUSIONS

CCN5 can reverse established CF by inhibiting the generation of and enhancing apoptosis of myofibroblasts in the myocardium. CCN5 may provide a novel platform for the development of targeted anti-CF therapies.

Effects of Vitamin D on Cardiac Function in Patients With Chronic HF: The VINDICATE Study

Background

Patients with chronic heart failure (HF) secondary to left ventricular systolic dysfunction (LVSD) are frequently deficient in vitamin D. Low vitamin D levels are associated with a worse prognosis.

Objectives

The VINDICATE (VitamIN D treatIng patients with Chronic heArT failurE) study was undertaken to establish safety and efficacy of high-dose 25 (OH) vitamin D₃ (cholecalciferol) supplementation in patients with chronic HF due to LVSD.

Methods

We enrolled 229 patients (179 men) with chronic HF due to LVSD and vitamin D deficiency (cholecalciferol <50 nmol/l [<20 ng/ml]). Participants were allocated to 1 year of vitamin D₃ supplementation (4,000 IU [100 μg] daily) or matching non−calcium-based placebo. The primary endpoint was change in 6-minute walk distance between baseline and 12 months. Secondary endpoints included change in LV ejection fraction at 1 year, and safety measures of renal function and serum calcium concentration assessed every 3 months.

Results

One year of high-dose vitamin D₃ supplementation did not improve 6-min walk distance at 1 year, but was associated with a significant improvement in cardiac function (LV ejection fraction +6.07% [95% confidence interval (CI): 3.20 to 8.95; p < 0.0001]); and a reversal of LV remodeling (LV end diastolic diameter -2.49 mm [95% CI: -4.09 to -0.90; p = 0.002] and LV end systolic diameter -2.09 mm [95% CI: -4.11 to -0.06 p = 0.043]).

Conclusions

One year of 100 μg daily vitamin D₃ supplementation does not improve 6-min walk distance but has beneficial effects on LV structure and function in patients on contemporary optimal medical therapy. Further studies are necessary to determine whether these translate to improvements in outcomes. (VitamIN D Treating patIents With Chronic heArT failurE [VINDICATE]; NCT01619891)

Heart acceleration and deceleration capacities associated with dilated cardiomyopathy

BACKGROUND

Heart rate deceleration capacity and acceleration capacity are novel autonomic nervous system indicators of cardiac neural regulation. Dilated cardiomyopathy (DCM) changes cardiac electrophysiology; however, how deceleration capacity and acceleration capacity associated with DCM remain unclear.

MATERIALS AND METHODS

To evaluate the association between heart rate acceleration capacity, deceleration capacity and DCM, 66 DCM patients with DCM and 209 controls were enrolled in the study. Demographic data, echocardiographic data, heart rate variability, deceleration capacity and acceleration capacity were collected. The association pattern between DCM and these indexes were studied by multiple logistic regression analysis.

RESULTS

Deceleration capacity and acceleration capacity were independent risk factors for DCM with an odds ratio (OR) and 95% confidence interval (CI), determined by multiple logistic regression analysis, of 7·97 (3·87-16·42) and 0·09 (0·05-0·19), respectively. Univariate ordinal logistic regression analysis showed that acceleration capacity, fastest heart rate, standard deviation of normal-to-normal RR intervals (SDNN) and left ventricular ejection fraction (LEVF) associated with heart failure grade. The OR for each covariate was further adjusted for the effects of other significant covariates in multivariate ordinal logistic regression analysis. Acceleration capacity, fastest heart rate and LVEF were still independent risk factors in the final equation with ORs of 1·32 (1·03-1·79), 1·04 (0·01-1·07) and 0·46 (0·23-0·93), respectively.

CONCLUSION

Heart rate acceleration capacity and deceleration capacity are independent risk factors for DCM, and acceleration capacity is a predictive factor for heart failure exacerbation in patients with DCM.

Heart Failure With Preserved Ejection Fraction: What Is in a Name?

Evidence-based management of heart failure (HF) with preserved left ventricular ejection fraction (LVEF; HFpEF) remains a major gap in the care of patients with HF. Clinical trials directed toward the population with HFpEF have been disappointing, although renin-angiotensin-aldosterone system blockade appears to prevent HF in populations predisposed to HFpEF. This paradox may partly be because of inhomogeneity within the HF populations studied. Although the term HFpEF is often used to imply a specific diagnosis, in fact this constellation may be due to a large variety of disease states with different underlying pathophysiologic mechanisms. Furthermore, in patients with HF, regardless of LVEF, myocardial dysfunction is common during both systole and diastole, and LVEF is influenced at least as much by the pattern of left ventricular remodeling as it is by myocardial contractility. The most common clinical-pathologic syndrome responsible for HFpEF is strongly associated with hypertension, with the metabolic syndrome, and with older age. Recent findings support that this condition is mediated via endothelial dysfunction, inflammation, oxidative stress, myocyte hypertrophy, and altered collagen turnover. We, therefore, propose the terms "metabolic HF" and "senile HF" to describe this specific disease state. The search for therapies designed to prevent, halt, or reverse HF should more strongly focus on populations carefully selected to represent specific underlying cardiovascular disease states.

Diffusion Tensor Imaging of Healthy and Infarcted Porcine Hearts: Study on the Impact of Formalin Fixation

BACKGROUND

Due to complexities of in-vivo cardiac diffusion tensor imaging (DTI), ex-vivo formalin-fixed specimens are used to investigate cardiac remodeling in diseases, and reported results have shown conflicting trends. This study investigates the impact of formalin-fixation on diffusion properties and optimizes tracking parameters based on controls to understand remodeling in myocardial-infarction (MI).

METHODS

DTI was performed on 4 healthy (controls) and 4 MI induced formalin-fixed (PoMI) ex-vivo porcine hearts. Controls were scanned pre-fixation (PrCtrl) and re-scanned (PoCtrl) after formalin-fixation. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) were estimated in all hearts. Tracking parameters (FA, tract termination angle (TTA), fiber-length) were optimized in controls and then used to investigate structural remodeling in PoMI hearts.

RESULTS

Fixation increased ADC and decreased FA. PoMI showed increased ADC but decreased FA in infarcted zone compared to remote zone. TTA showed sharp increase in slope from 5°-10°, which flattened after 25° in all groups. Mean fiber-length for different tracking length range showed that PoCtrl had shorter fibers compared to PrCtrl. Fibers around infarction were shorter in length and disarrayed compared to PoCtrl group.

CONCLUSION

Formalin-fixation affects diffusion properties and hence DTI parametric trends observed in pathology may be influenced by the fixation process which can cause contradictory findings.

Postinfarct Left Ventricular Remodelling: A Prevailing Cause of Heart Failure

Heart failure is a chronic disease with high morbidity and mortality, which represents a growing challenge in medicine. A major risk factor for heart failure with reduced ejection fraction is a history of myocardial infarction. The expansion of a large infarct scar and subsequent regional ventricular dilatation can cause postinfarct remodelling, leading to significant enlargement of the left ventricular chamber. It has a negative prognostic value, because it precedes the clinical manifestations of heart failure. The characteristics of the infarcted myocardium predicting postinfarct remodelling can be studied with cardiac magnetic resonance and experimental imaging modalities such as diffusion tensor imaging can identify the changes in the architecture of myocardial fibers. This review discusses all the aspects related to postinfarct left ventricular remodelling: definition, pathogenesis, diagnosis, consequences, and available therapies, together with experimental interventions that show promising results against postinfarct remodelling and heart failure.

The current status of heart failure diagnostic biomarkers

Heart failure (HF) affects approximately 23 million individuals worldwide and this number is increasing, due to an aging and growing population. Early detection of HF is crucial in the management of this debilitating disease. Current diagnostic methods for HF rely heavily on clinical imaging techniques and blood analysis, which makes them less than ideal for population-based screening purposes. Studies focusing on developing novel biomarkers for HF have utilized various techniques and biological fluids, including urine and saliva. Promising results from these studies imply that these body fluids can be used in evaluating the clinical manifestation of HF and will one day be integrated into a clinical workflow and facilitate HF management.

Endocardial Remodeling in Heart Failure Patients with Impaired and Preserved Left Ventricular Systolic Function--A Magnetic Resonance Image Study

Left ventricular (LV) trabeculation has been studied in certain forms of cardiomyopathy. However, the changes of LV endocardial trabeculation during the remodeling process leading to heart failure (HF) are unclear. Seventy-four patients with systolic heart failure (SHF), 65 with heart failure with preserved ejection fraction (HFpEF) and 61 without HF were prospectively enrolled. All subjects received magnetic resonance imaging (MRI) study including cine, T1 and late gadolinium enhancement (LGE) images. Trabecular-papillary muscle (TPM) mass, fractal dimension (FD) and extracellular volume (ECV) were derived. The results showed that TPM mass index was higher in patients with SHF than that in patients with HFpEF and non-HF. The TPM mass-LV mass ratio (TPMm/LVM) was higher in SHF group than that in HFpEF and non-HF. FD was not different among groups. The presence of LGE was inversely associated with TPM mass index and TPMm/LVM while the ECV were positively associated with TPMm/LVM. The FD was positively associated with LV chamber size. In conclusion, TPM increases in patients with SHF and are probably related to myocardial cell hypertrophy and fibrotic repair during remodeling. The FD increases with the dilatation of LV chamber but remain unchanged with the deterioration of LV function.

Effect of tricuspid regurgitation and the right heart on survival after transcatheter aortic valve replacement: insights from the Placement of Aortic Transcatheter Valves II inoperable cohort

BACKGROUND

Tricuspid regurgitation (TR) and right ventricular (RV) dysfunction adversely affect outcomes in patients with heart failure or mitral valve disease, but their impact on outcomes in patients with aortic stenosis treated with transcatheter aortic valve replacement has not been well characterized.

METHODS AND RESULTS

Among 542 patients with symptomatic aortic stenosis treated in the Placement of Aortic Transcatheter Valves (PARTNER) II trial (inoperable cohort) with a Sapien or Sapien XT valve via a transfemoral approach, baseline TR severity, right atrial and RV size and RV function were evaluated by echocardiography according to established guidelines. One-year mortality was 16.9%, 17.2%, 32.6%, and 61.1% for patients with no/trace (n=167), mild (n=205), moderate (n=117), and severe (n=18) TR, respectively (P<0.001). Increasing severity of RV dysfunction as well as right atrial and RV enlargement were also associated with increased mortality (P<0.001). After multivariable adjustment, severe TR (hazard ratio, 3.20; 95% confidence interval, 1.50-6.82; P=0.003) and moderate TR (hazard ratio, 1.60; 95% confidence interval, 1.02-2.52; P=0.042) remained associated with increased mortality as did right atrial and RV enlargement, but not RV dysfunction. There was an interaction between TR and mitral regurgitation severity (P=0.04); the increased hazard of death associated with moderate/severe TR only occurred in those with no/trace/mild mitral regurgitation.

CONCLUSIONS

In inoperable patients treated with transcatheter aortic valve replacement, moderate or severe TR and right heart enlargement are independently associated with increased 1-year mortality; however, the association between moderate or severe TR and an increased hazard of death was only found in those with minimal mitral regurgitation at baseline. These findings may improve our assessment of anticipated benefit from transcatheter aortic valve replacement and support the need for future studies on TR and the right heart, including whether concomitant treatment of TR in operable but high-risk patients with aortic stenosis is warranted.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01314313.

Sphingosine-1-Phosphate Receptor Agonist Fingolimod Increases Myocardial Salvage and Decreases Adverse Postinfarction Left Ventricular Remodeling in a Porcine Model of Ischemia/Reperfusion

BACKGROUND

Fingolimod, a sphingosine-1-phosphate receptor agonist, is used for the treatment of multiple sclerosis and exerts antiapoptotic properties. We hypothesized that sphingosine-1-phosphate receptor activation with fingolimod during acute myocardial infarction (MI) inhibits apoptosis, leading to increased myocardial salvage, reduced infarct size, and mitigated left ventricular (LV) remodeling in a porcine model of ischemia/reperfusion.

METHODS AND RESULTS

Ischemia/reperfusion was induced in pigs by balloon occlusion of the left anterior descending artery, followed by reperfusion. Animals randomly received fingolimod or saline (control). In short-term experiments, fingolimod treatment activated the cardioprotective reperfusion injury salvage kinase and survivor activating factor enhancement pathways in the infarct border zone 24 hours after MI, leading to decreased cardiomyocyte apoptosis and reduced myocardial oxidative stress. These effects were abolished by specific inhibitors of both pathways, demonstrating that fingolimod-induced cardioprotection was mediated by reperfusion injury salvage kinase and survivor activating factor enhancement pathways. In long-term experiments, fingolimod significantly improved myocardial salvage, reduced infarct size, and improved systolic LV function measured by cardiac magnetic resonance 1 week and 1 month after MI. Importantly, fingolimod mitigated the development of adverse post-MI LV remodeling 1 month after MI. Specifically, fingolimod treatment led to a significant reduction in LV mass, LV dilatation, and neurohormonal activation, and it preserved LV geometry. Furthermore, fingolimod decreased interstitial fibrosis, cardiomyocyte hypertrophy, and chronic activation of Akt and extracellular receptor kinase 1/2 in the remote noninfarcted myocardium.

CONCLUSIONS

Sphingosine-1-phosphate receptor activation with fingolimod during acute MI reduced infarct size via the reperfusion injury salvage kinase and survivor activating factor enhancement pathways, improved systolic LV function, and mitigated post-MI LV remodeling. Our data strongly support a cardioprotective role for sphingosine-1-phosphate receptor activation during MI.

Significance of myocardial tenascin-C expression in left ventricular remodelling and long-term outcome in patients with dilated cardiomyopathy

Aim

Dilated cardiomyopathy (DCM) has a variety of causes, and no useful approach to predict left ventricular (LV) remodelling and long‐term outcome has yet been established. Myocardial tenascin‐C (TNC) is known to appear under pathological conditions, possibly to regulate cardiac remodelling. The aim of this study was to clarify the significance of myocardial TNC expression in LV remodelling and the long‐term outcome in DCM.

Methods and results

One hundred and twenty‐three consecutive DCM patients who underwent endomyocardial biopsy for initial diagnosis were studied. Expression of TNC in biopsy sections was analysed immunohistochemically to quantify the ratio of the TNC‐positive area to the whole myocardial tissue area (TNC area). Clinical parameters associated with TNC area were investigated. The patients were divided into two groups based on receiver operating characteristic analysis of TNC area to predict death: high TNC group with TNC area ≥2.3% (22 patients) and low TNC group with TNC area <2.3% (101 patients). High TNC was associated with diabetes mellitus. Comparing echocardiographic findings between before and 9 months after endomyocardial biopsy, the low TNC group was associated with decreased LV end‐diastolic diameter and increased LV ejection fraction, whereas the high TNC group was not. Survival analysis revealed a worse outcome in the high TNC group than in the low TNC group (P < 0.001). Multivariable Cox regression analysis revealed that TNC area was independently associated with poor outcome (HR = 1.347, P = 0.032).

Conclusions

Increased myocardial TNC expression was associated with worse LV remodeling and long‐term outcome in DCM.

A randomized, double-blind, placebo-controlled trial to evaluate the safety and effectiveness of intracoronary application of a novel bioabsorbable cardiac matrix for the prevention of ventricular remodeling after large ST-segment elevation myocardial infarction: Rationale and design of the PRESERVATION I trial

Postinfarction left ventricular (LV) remodeling can result in chronic heart failure and functional impairment. Although pharmacological strategies for established heart failure can be beneficial, preventing remodeling remains a challenge. Injectable bioabsorbable alginate or "bioabsorbable cardiac matrix" (BCM), composed of an aqueous mixture of sodium alginate and calcium gluconate, is a sterile colorless liquid that is a polysaccharide polymer produced from brown seaweed. When exposed to excess ionized calcium present in infarcted myocardium, BCM assembles to form a flexible gel, structurally resembling extracellular matrix, which provides temporary structural support to the infarct zone through and beyond the time needed for mature fibrotic tissue to develop. The PRESERVATION I trial is an early phase randomized, double-blind, placebo-controlled trial comparing intracoronary application of 4 mL of BCM with saline control in patients who develop large infarctions after successful reperfusion of large ST-segment elevation myocardial infarction (MI). Subjects will be randomized 2:1 to either BCM or saline control and will have the study device deployed through an intracoronary microcatheter in the infarct-related artery 2 to 5 days after index ST-segment elevation MI treated with successful primary or rescue percutaneous coronary intervention. The primary effectiveness end point is the absolute change in LV diastolic volume index as measured by 3-dimensional echocardiography from baseline to 6 months after BCM deployment. Secondary effectiveness end points include clinical outcomes, patient-reported quality of life, additional echocardiographic measures, and functional status measures. In summary, the PRESERVATION I trial is a randomized double-blind trial evaluating the effectiveness and safety of the novel device BCM in preventing LV remodeling patients who have large MIs despite undergoing successful primary or rescue percutaneous coronary intervention.

Left ventricular reconstruction: update to left ventricular aneurysm/reshaping techniques

The increase in left ventricular (LV) volume after a myocardial infarction (MI) is a component of the remodelling process and is associated with a poor clinical outcome. Hence, the current management strategy for ischaemic LV dysfunction has been aimed at reversing the remodelling process. Surgical LV reconstruction (LVR) has been introduced as an optional therapeutic strategy aimed at reducing LV volumes through the exclusion of the scar tissue, thereby restoring the physiological volume and shape and improving LV function and clinical status. Until recently, several studies have shown that surgical LVR is effective and relatively safe, with a favourable 5-year outcome. However, in spite of the large amount of reports drawn on various data sets, the additional benefit of LVR to CABG remains debated. We briefly discuss the rationale for surgically reversing LV remodelling through LVR, and, more extensively, the technique and the indications to the best of our knowledge.

Analyzing Remodeling of Cardiac Tissue: A Comprehensive Approach Based on Confocal Microscopy and 3D Reconstructions

Microstructural characterization of cardiac tissue and its remodeling in disease is a crucial step in many basic research projects. We present a comprehensive approach for three-dimensional characterization of cardiac tissue at the submicrometer scale. We developed a compression-free mounting method as well as labeling and imaging protocols that facilitate acquisition of three-dimensional image stacks with scanning confocal microscopy. We evaluated the approach with normal and infarcted ventricular tissue. We used the acquired image stacks for segmentation, quantitative analysis and visualization of important tissue components. In contrast to conventional mounting, compression-free mounting preserved cell shapes, capillary lumens and extracellular laminas. Furthermore, the new approach and imaging protocols resulted in high signal-to-noise ratios at depths up to 60 µm. This allowed extensive analyzes revealing major differences in volume fractions and distribution of cardiomyocytes, blood vessels, fibroblasts, myofibroblasts and extracellular space in control vs. infarct border zone. Our results show that the developed approach yields comprehensive data on microstructure of cardiac tissue and its remodeling in disease. In contrast to other approaches, it allows quantitative assessment of all major tissue components. Furthermore, we suggest that the approach will provide important data for physiological models of cardiac tissue at the submicrometer scale.

Traditional Chinese medicine Qili qiangxin inhibits cardiomyocyte apoptosis in rats following myocardial infarction

The aim of the present study was to examine the effect of the traditional Chinese medicine Qili qiangxin on cardiomyocyte apoptosis following myocardial infarction (MI) in a rat model. MI was induced in rats by ligation of the anterior descending coronary artery. Survivors were randomly divided into the sham operation, MI, and Qili qiangxin groups (4 g/kg per day). After 28 days, infarction size was measured. In the non-infarcted zones (NIZ), the apoptotic index (AI) was measured by terminal deoxynucleotidyl transferase (TdT)-mediated digoxigenin-conjugated dUTP nick-end labeling (TUNEL). Expression of Fas was detected by immunohistochemistry, and the expression of xanthine oxidase (XO) and caspase-3 by western blot analysis. In addition, the XO and ^·O₂⁻, ^·OH-scavenging activity of myocardial tissue in NIZ was measured by colorimetry. Compared to the MI group, AI and the expression of Fas and caspase-3 were significantly decreased in NIZ. The activity of XO was also considerably reduced while ^·O₂⁻ and ^·OH-scavenging activity was significantly increased in the Qili qiangxin group. Ventricular remodeling was attenuated but there were no significant differences in infarct size (IS) or XO expression levels between the Qili qiangxin and MI groups. In conclusion, the results suggest that Qili qiangxin may inhibit cardiomyocyte apoptosis in NIZ in rats. The potential mechanism involved may be associated with its ability to reduce reactive oxygen species (ROS) and to depress the expression of Fas and caspase-3.

MiRNAs as potential molecular targets in heart failure

Pathogenesis of heart diseases is associated with an altered expression profile of hundreds of genes. miRNAs are a newly identified layer of gene regulation operating at the post-transcriptional level by pairing to complementary base sequences in target mRNAs. Genetic data have identified the roles of miRNAs in basic pathological processes associated with heart failure: apoptosis, fibrosis, myocardial hypertrophy and cardiac remodeling. Many reports demonstrated that aberrantly expressed miRNAs and their modulation have effects on cardiac insufficiency. Here, we overview the advances in miRNAs as potential targets in the modulation of the heart failure phenotype. miRNA-based therapy holds great promise as a future strategy for treating heart diseases and identifying emerging signaling pathways responsible for the progression of heart failure.