Disorder-to-order transition of long fibers contained in evaporating sessile drops

A liquid drop containing a long fiber is a complex system whose configuration is determined by an interplay of elastic stresses in the fiber and capillary forces due to the liquid. We study the morphological evolution of fibers that are much longer than the drop diameter in evaporating sessile drops. After insertion, the fibers are either found in an ordered or disordered state, with increasing disorder for increasing fiber length. Upon evaporation, the order increases, in such a way that the final configuration deposited on the solid surface is either a circle, an ellipse, or 8-shaped. The morphology of the deposit depends on the fiber length and the elastocapillary length, both non-dimensionalized with the characteristic drop size, which we classify in a morphology regime map. The disorder-to-order transition allows depositing ordered fiber structures on solid surfaces even in cases of a strongly disordered state after fiber insertion. Combined with technologies such as inkjet printing, this process could open new avenues to decorate surfaces with filamental structures whose morphology can be controlled by varying the fiber length.

Auxiliary Subunits Control Function and Subcellular Distribution of AMPA Receptor Complexes in NG2 Glia of the Developing Hippocampus

Synaptic and axonal glutamatergic signaling to NG2 glia in white matter is critical for the cells' differentiation and activity dependent myelination. However, in gray matter the impact of neuron-to-NG2 glia signaling is still elusive, because most of these cells keep their non-myelinating phenotype throughout live. Early in postnatal development, hippocampal NG2 glia express AMPA receptors with a significant Ca²⁺ permeability allowing for plasticity of the neuron-glia synapses, but whether this property changes by adulthood is not known. Moreover, it is unclear whether NG2 glia express auxiliary transmembrane AMPA receptor related proteins (TARPs), which modify AMPA receptor properties, including their Ca²⁺ permeability. Through combined molecular and functional analyses, here we show that hippocampal NG2 glia abundantly express TARPs γ4, γ7, and γ8 as well as cornichon (CNIH)-2. TARP γ8 undergoes profound downregulation during development. Receptors of adult NG2 glia showed an increased sensitivity to blockers of Ca²⁺ permeable AMPA receptors, but this increase mainly concerned receptors located close to the soma. Evoked synaptic currents of NG2 glia were also sensitive to blockers of Ca²⁺ permeable AMPA receptors. The presence of AMPA receptors with varying Ca²⁺ permeability during postnatal maturation may be important for the cells' ability to sense and respond to local glutamatergic activity and for regulating process motility, differentiation, and proliferation.

Recommendations for return to sports after total hip arthroplasty are becoming less restrictive as implants improve

INTRODUCTION

Total hip arthroplasty (THA) surgeries are expected to exponentially increase in the upcoming years, likely because of the overall broader indication of THAs. With these developments, an increasing number of younger (< 50 years) and active patients will receive surgical interventions, and expectations for an active lifestyle will accordingly increase. In addition, surgeons now have a growing array of techniques and implant materials to choose from. Despite these developments, evidence to provide the best standard-of-care to patients with high expectations for return to sports (RTS) is scarce and urgently needed. What recommendations do arthroplasty surgeons currently make to patients with high return to sports expectations, what factors may influence their recommendations and what surgical techniques and implant specifications are considered favorable in the treatment of patients with a more active lifestyle? This study was conducted to analyze the current recommendations, patient assessment, and patient counseling after THA to identify trends and relevant factors for surgical decision-making in patients with high-RTS expectations.

MATERIAL AND METHODS

We designed a questionnaire comprising five general items and 19 specific items that included 46 sub-items for hip arthroplasty and conducted a survey among 300 German surgeons specialized in arthroplasty at the German Arthroplasty Society (AE) to assess expert opinions, recommendations, surgical decision-making, and patient counseling for patients with high expectations for RTS after THA.

RESULTS

The majority of surgeons (81.9%) were in favor of RTS after THA. Risks associated with sports after THA were considered minimal (1%), with periprosthetic fractures ranking highest, followed by hip dislocation and polyethylene wear. Some surgical decision-making was influenced by high-RTS expectations in regard to implant fixation, stem type, femoral head diameter, and bearing-surface tribology. We observed an increasingly liberal counseling of patients for high-impact sports.

CONCLUSION

With the improvement of implants and surgical techniques, surgeons are more willing to encourage patients to adopt a more active lifestyle. However, the true long-term limitations need further investigation in future studies.

LEVEL OF EVIDENCE

5 Expert opinions.

Protein Transport and Concentration by Electrophoresis in Two-phase Microflows

This work aims at a new class of methods for electric field-mediated separation of biomolecules. In contrast to standard techniques, electrophoretic transport was not performed in a single-phase homogenous fluid, but in a system of stratified layers. The large surface-to-volume ratio characteristic for microfluidic systems allows the interactions of biomolecules with liquid/liquid interfaces to be examined and the suitability of corresponding effects for applications in the field of biomolecular separations and enrichment to be assessed. To perform these types of studies, a micro flow cell was fabricated into which two coflowing immiscible liquid phases can be introduced. Subsequently, the electrophoretic transport of biomolecules driven by an electric field perpendicular to the channel was examined.

To investigate the transport phenomena related to electrophoresis in stratified two-phase systems, aqueous solutions consisting of polyethylene glycol and dextran were prepared, which allowed a stable interface to develop. Transport within one phase and an enrichment of proteins at the phase boundary has been established. In addition, other kinds of fluid combinations such as water and propylene carbonate have been examined, also supporting the enrichment of proteins at the phase boundary.

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.

Improvement of risk assessment in systemic light-chain amyloidosis using human placental growth factor

BACKGROUND

Vascular amyloid deposition is common in light-chain amyloidosis resulting in endothelial dysfunction. Human placental growth factor (PlGF), a member of the vascular endothelial growth factor family was found to be altered in diverse pathological conditions, e.g. endothelial dysfunction. This study evaluated the clinical role of PlGF in light-chain amyloidosis.

METHODS

PlGF (cobas-PlGF, Roche Diagnostics, Mannheim, Germany) was analyzed in 125 consecutive patients with AL and correlated with diverse clinical parameters including mortality.

RESULTS

Kidney (n = 76) and heart (n = 57) were predominantly affected by amyloid deposition. Median PlGF was 26.3 (21.1-42.1) ng/L, NT-proBNP 3649 (1124-8581) pg/mL, and hs-TnT 42 (21-107) ng/L. PlGF increased with number of organs involved and with deterioration of renal function. A significant correlation of PlGF with hs-TnT (ρ = 0.306; p = 0.0007) and NT-proBNP (ρ = 0.315; p = 0.0006) was observed, but no correlation was observed with clinical, echocardiography, and electrocardiography parameters of cardiac involvement. In this cohort 1-year all-cause mortality was 19.2 %. The best cutoff discriminating survivors and non-survivors was 28.44 ng/L (sensitivity 66.7 %; specificity 78.1 %). A three-step risk model including hs-TnT and NT-proBNP revealed a better discrimination if patients at intermediary risk were additionally stratified by PlGF. Net reclassification index was 37.2 % (p = 0.002). Multivariate analysis revealed PlGF, difference of involved and uninvolved light chain, number of organs involved and risk class according to troponin T and NT-proBNP as independent predictors of mortality.

CONCLUSION

Plasma PlGF values in AL are invariably associated with the number of involved organs, but not with clinical, echocardiography, and electrocardiography parameters of cardiac involvement. PlGF provide useful information for risk stratification of patients at intermediary risk according to hs-TnT and NT-proBNP.

Reliability of noninvasive assessment of systolic pulmonary artery pressure by Doppler echocardiography compared to right heart catheterization: analysis in a large patient population

Background

Pulmonary artery pressure (PAP) is an important marker in cardiovascular disorders, being closely associated with morbidity and mortality. Noninvasive assessment by Doppler echocardiography is recommended by current guidelines. So far, the reliability of this method has been assessed only in small studies with contradictory results. Therefore, the aim of this study was to analyze the reliability of noninvasive PAP assessment by Doppler echocardiography compared to invasive measurements in a large patient population.

Methods and Results

We retrospectively analyzed data from a large tertiary cardiology department over 6 years in order to compare invasively measured PAP to estimated PAP from echocardiography examinations. N=15 516 patients fulfilled inclusion criteria and n=1695 patients with timely matched examinations (within 5 days) were analyzed. In n=1221 (72%) patients, pulmonary hypertension (PH) was diagnosed invasively (postcapillary PH: n=1122 [66%]; precapillary PH: n=99 [6%]). Systolic pulmonary artery pressure (sPAP) was 45.3±15.5 mm Hg by Doppler echocardiography and 47.4±16.4 mm Hg by right heart catheterization. Pearson's correlation coefficient was r=0.87 (P<0.0001). Mean right atrial pressure (RAP) was 12.0±5.7 mm Hg by right heart catheterization and was estimated to be 12.1±6.6 mm Hg by echocardiography (r=0.82, P<0.0001). Bland–Altman analysis showed a bias of −2.0 mm Hg for sPAP (95% limits of agreement −18.1 to +14.1 mm Hg) and +1.0 mm Hg for RAP (95% limits of agreement +0.1 to +1.9 mm Hg). Noninvasive diagnosis of pulmonary hypertension with Doppler echocardiography had a good sensitivity (87%) and specificity (79%), positive and negative predictive values (91% and 70%), as well as accuracy (85%) for a sPAP cut‐off value of 36 mm Hg (AUC 0.91, P<0.001, CI 0.90 to 0.93).

Conclusions

In this study, Doppler echocardiography proved to be a reliable method for the assessment of sPAP, being well suited to establish the noninvasive diagnosis of pulmonary hypertension in patients with cardiac diseases.

Noninvasive risk stratification of patients with transthyretin amyloidosis

OBJECTIVES

We sought to evaluate noninvasive parameters by electrocardiography, echocardiography, technetium-99m-3,3-diphosphono-1,2-propanodicarboxylic acid ((99m)Tc-DPD) scintigraphy, and cardiac magnetic resonance for the prediction of all-cause mortality in patients with cardiac transthyretin amyloidosis (ATTR).

BACKGROUND

ATTR may present with highly variable symptoms, including polyneuropathy and cardiomyopathy, the latter being associated with a poor outcome. However, data on noninvasive risk stratification of ATTR are limited.

METHODS

A total of 70 patients with ATTR were evaluated by echocardiography, cardiac biomarkers, and (99m)Tc-DPD scintigraphy. Cardiac magnetic resonance was performed in 30 patients. Echocardiographic findings and plasma levels of biomarkers were correlated with results of quantitative analysis of scintigraphy using a region-of-interest technique (whole-body as well as heart tracer retention). Receiver-operating characteristic (ROC) analysis was performed to calculate a cutoff value of (99m)Tc-DPD scintigraphy for heart retention for the diagnosis of cardiac amyloid involvement with the highest sensitivity and specificity. Univariate and multivariate analyses were performed in patients with cardiac involvement (n = 60) to determine noninvasive predictors of all-cause mortality.

RESULTS

Scintigraphy findings correlated with morphological (interventricular septum thickness, left ventricular hypertrophy index) as well as functional (mitral annular systolic velocity, mitral/tricuspid annular plane systolic excursion) findings, cardiac biomarkers, renal function, and late gadolinium enhancement. The ROC-derived cutoff for the detection of cardiac amyloidosis by scintigraphic heart tracer retention was 4.8%. Univariate Cox regression revealed N-terminal pro-B-type natriuretic peptide, troponin T, mitral annular plane systolic excursion, and left ventricular hypertrophy index as predictors of all-cause mortality. However, on multivariate analysis, troponin T remained the only independent predictor of survival. The ROC-derived cutoff value of troponin T predicting all-cause mortality with the highest sensitivity (80.0%) and specificity (68.7%) was 0.0375 ng/l.

CONCLUSIONS

Quantitative analysis of tracer retention is capable of characterizing the severity of cardiac involvement in ATTR. By multivariate analysis, troponin T remained the only independent predictor of survival.

Left atrial appendage occlusion in atrial fibrillation after intracranial hemorrhage

OBJECTIVE

To evaluate the safety and feasibility of percutaneous left atrial appendage occlusion (LAAO) in patients with atrial fibrillation (AF) and previous intracranial hemorrhage (ICH).

METHODS

In an explorative, prospective, single-center, observational study, LAAO was performed in patients with previous ICH and AF using the Amplatzer Cardiac Plug device. Risks of ischemic strokes and hemorrhagic complications were estimated using the CHA2DS2Vasc score and the HAS-BLED score. Before and 1, 6, 12, and 24 months after the procedure, clinical status and complications were recorded. Major complications were predefined as periprocedural stroke, death, pericardial effusion, and device embolism.

RESULTS

LAAO was performed in 20 patients. Based on CHA2DS2Vasc score (mean 4.5 ± 1.4) and HAS-BLED score (mean 4.7 ± 1.0), annual risks of stroke and hemorrhagic complications were 4.0%-6.7% and 8.7%-12.5%, respectively. No patient had a procedure-related complication. Minor postprocedural complications were observed in 4/20 patients (2 inguinal hematoma, 1 self-limiting asystole, and 1 thrombus formation on device). No ischemic or hemorrhagic stroke occurred during a mean follow-up of 13.6 ± 8.2 months.

CONCLUSIONS

In this first study of LAAO in patients with previous ICH, LAAO appears feasible and safe. A larger, controlled trial is needed to assess the efficacy and safety of the procedure compared to other preventive measures.

CLASSIFICATION OF EVIDENCE

This study provides Class III evidence that in patients with a history of previous ICH and AF, percutaneous LAAO is safe and feasible.

Heart rate reduction for 36 months with ivabradine reduces left ventricular mass in cardiac allograft recipients: a long-term follow-up study

Background

Due to graft denervation, sinus tachycardia is a common problem after heart transplantation, underlining the importance of heart rate control without peripheral effects. However, long-term data regarding the effects of ivabradine, a novel I_f channel antagonist, are limited in patients after heart transplantation.

Methods

In this follow-up analysis, the resting heart rate, left ventricular mass indexed to body surface area (LVMI), tolerability, and safety of ivabradine therapy were evaluated at baseline and after 36 months in 30 heart transplant recipients with symptomatic sinus tachycardia versus a matched control group.

Results

During the study period, ivabradine medication was stopped in three patients (10% of total). Further analysis was based on 27 patients with 36 months of drug intake. The mean patient age was 53.3±11.3 years and mean time after heart transplantation was 5.0±4.8 years. After 36 months, the mean ivabradine dose was 12.0±3.4 mg/day. Resting heart rate was reduced from 91.0±10.7 beats per minute before initiation of ivabradine therapy (ie, baseline) to 81.2±9.8 beats per minute at follow-up (P=0.0006). After 36 months of ivabradine therapy, a statistically significant reduction of LVMI was observed (104.3±22.7 g at baseline versus 93.4±18.4 g at follow-up, P=0.002). Hematologic, renal, and liver function parameters remained stable during ivabradine therapy. Except for a lower mycophenolate mofetil dose at follow-up (P=0.02), no statistically significant changes in immunosuppressive drug dosage or blood levels were detected. No phosphenes were observed during 36 months of ivabradine intake despite active inquiry.

Conclusion

In line with previously published 12-month data, heart rate reduction with ivabradine remained effective and safe in chronic stable patients after heart transplantation, and also during 36-month long-term follow-up. Further, a significant reduction of LVMI was observed only during ivabradine therapy. Therefore, ivabradine may have a sustained long-term beneficial effect with regard to left ventricular remodeling in heart transplant patients.

Renal sympathetic denervation therapy in the real world: results from the Heidelberg registry

INTRODUCTION

Renal sympathetic denervation (RDN) is a novel treatment option in patients with treatment-resistant arterial hypertension. A subset of recently published randomized and non-randomized trials indicates that RDN leads to sustained lowering of blood pressure (BP) under controlled study conditions. However, registry data that allow evaluation of safety and efficacy in a real-world setting are largely missing.

METHODS

Sixty-three consecutive patients with treatment-resistant hypertension underwent RDN with the radiofrequency-based Symplicity™ catheter. As part of our prospective registry, treatment efficacy and safety were monitored after 3, 6, and 12 months.

RESULTS

At 6 months follow-up, office systolic BP significantly improved by 19 + 23 mmHg as compared to baseline, while diastolic BP values reduced by 6 + 13 mmHg (p < 0.05). One year after RDN, office BP levels further improved (26 + 25 mmHg in systolic BP and 9 + 13 mmHg in diastolic BP, respectively), even though 19 patients had reduced the number and/or dosage of antihypertensive agents. The response rate, defined as reduction of office systolic BP of ≥ 10 mmHg, was 73% after 6 months. Baseline BP was the only significant predictor of blood pressure response, whereas no correlation was found between the number of ablation points and the individual changes in office blood pressure. Interestingly, patients with challenging renal anatomy profited somewhat less from the procedure than those with "normal" renal anatomy. Procedure related adverse events occurred in three patients (4.7%) and were limited to vascular access complications.

CONCLUSIONS

RDN with the Symplicity™ system is safe and effective in patients with treatment-resistant hypertension also in a real-world setting.

Isotachophoresis with emulsions

An experimental study on isotachophoresis (ITP) in which an emulsion is used as leading electrolyte (LE) is reported. The study aims at giving an overview about the transport and flow phenomena occurring in that context. Generally, it is observed that the oil droplets initially dispersed in the LE are collected at the ITP transition zone and advected along with it. The detailed behavior at the transition zone depends on whether or not surfactants (polyvinylpyrrolidon, PVP) are added to the electrolytes. In a system without surfactants, coalescence is observed between the droplets collected at the ITP transition zone. After having achieved a certain size, the droplets merge with the channel walls, leaving an oil film behind. In systems with PVP, coalescence is largely suppressed and no merging of droplets with the channel walls is observed. Instead, at the ITP transition zone, a droplet agglomerate of increasing size is formed. In the initial stages of the ITP experiments, two counter rotating vortices are formed inside the terminating electrolyte. The vortex formation is qualitatively explained based on a hydrodynamic instability triggered by fluctuations of the number density of oil droplets.

Multivariate miRNA signatures as biomarkers for non-ischaemic systolic heart failure

AIMS

Non-ischaemic heart failure is one of the today's most prevalent cardiovascular disorders. Since modern pharmacotherapy has proved to be very effective in delaying disease progression and preventing death, imaging modalities and molecular biomarkers play an important role in early identification and clinical management as well as risk assessment of patients. The present study evaluated for the first time whole peripheral blood miRNAs as novel biomarker candidates for non-ischaemic heart failure with reduced ejection fraction (HF-REF).

METHODS AND RESULTS

We assessed genome-wide miRNA expression profiles in 53 HF-REF patients and 39 controls. We could identify and validate several miRNAs that show altered expression levels in non-ischaemic HF-REF, discriminating cases from controls both as single markers or when combined in a multivariate signature. In addition, we demonstrate that the miRNAs of this signature significantly correlate with disease severity as indicated by left ventricular ejection fraction.

CONCLUSION

Our data further denote that miRNAs are potential biomarkers for systolic heart failure. Since their detection levels in whole blood are also related to the degree of left ventricular dysfunction, they may serve as objective molecular tools to assess disease severity and prognosis.

Alterations in cardiac DNA methylation in human dilated cardiomyopathy

Dilated cardiomyopathies (DCM) show remarkable variability in their age of onset, phenotypic presentation, and clinical course. Hence, disease mechanisms must exist that modify the occurrence and progression of DCM, either by genetic or epigenetic factors that may interact with environmental stimuli. In the present study, we examined genome-wide cardiac DNA methylation in patients with idiopathic DCM and controls. We detected methylation differences in pathways related to heart disease, but also in genes with yet unknown function in DCM or heart failure, namely Lymphocyte antigen 75 (LY75), Tyrosine kinase-type cell surface receptor HER3 (ERBB3), Homeobox B13 (HOXB13) and Adenosine receptor A2A (ADORA2A). Mass-spectrometric analysis and bisulphite-sequencing enabled confirmation of the observed DNA methylation changes in independent cohorts. Aberrant DNA methylation in DCM patients was associated with significant changes in LY75 and ADORA2A mRNA expression, but not in ERBB3 and HOXB13. In vivo studies of orthologous ly75 and adora2a in zebrafish demonstrate a functional role of these genes in adaptive or maladaptive pathways in heart failure.

Alterations in cardiac DNA methylation in human dilated cardiomyopathy

Dilated cardiomyopathies (DCM) show remarkable variability in their age of onset, phenotypic presentation, and clinical course. Hence, disease mechanisms must exist that modify the occurrence and progression of DCM, either by genetic or epigenetic factors that may interact with environmental stimuli. In the present study, we examined genome-wide cardiac DNA methylation in patients with idiopathic DCM and controls. We detected methylation differences in pathways related to heart disease, but also in genes with yet unknown function in DCM or heart failure, namely Lymphocyte antigen 75 (LY75), Tyrosine kinase-type cell surface receptor HER3 (ERBB3), Homeobox B13 (HOXB13) and Adenosine receptor A2A (ADORA2A). Mass-spectrometric analysis and bisulphite-sequencing enabled confirmation of the observed DNA methylation changes in independent cohorts. Aberrant DNA methylation in DCM patients was associated with significant changes in LY75 and ADORA2A mRNA expression, but not in ERBB3 and HOXB13. In vivo studies of orthologous ly75 and adora2a in zebrafish demonstrate a functional role of these genes in adaptive or maladaptive pathways in heart failure.

Refining diagnostic microRNA signatures by whole-miRNome kinetic analysis in acute myocardial infarction

BACKGROUND

Alterations in microRNA (miRNA) expression patterns in whole blood may be useful biomarkers of diverse cardiovascular disorders. We previously reported that miRNAs are significantly dysregulated in acute myocardial infarction (AMI) and applied machine-learning techniques to define miRNA subsets with high diagnostic power for AMI diagnosis. However, the kinetics of the time-dependent sensitivity of these novel miRNA biomarkers remained unknown.

METHODS

To characterize temporal changes in the expressed human miRNAs (miRNome), we performed here the first whole-genome miRNA kinetic study in AMI patients. We measured miRNA expression levels at multiple time points (0, 2, 4, 12, 24 h after initial presentation) in patients with acute ST-elevation myocardial infarction by using microfluidic primer extension arrays and quantitative real-time PCR. As a prerequisite, all patients enrolled had to have cardiac troponin T concentrations <50 ng/L on admission as measured with a high-sensitivity assay.

RESULTS

We found a subset of miRNAs to be significantly dysregulated both at initial presentation and during the course of AMI. Additionally, we identified novel miRNAs that are dysregulated early during myocardial infarction, such as miR-1915 and miR-181c*.

CONCLUSIONS

The present proof-of-concept study provides novel insights into the dynamic changes of the human miRNome during AMI.

Early assessment of infarct size and prediction of functional recovery by quantitative myocardial blush grade in patients with acute coronary syndromes treated according to current guidelines

PURPOSE

To determine whether quantification of myocardial blush grade (MBG) during cardiac catheterization can aid the determination of follow-up left ventricular (LV)-function in patients with ST-elevation and non-ST-elevation myocardial infarction (STEMI and NSTEMI).

METHODS

We prospectively examined patients with first STEMI (n = 46) and NSTEMI (n = 49). ECG-gated angiographic series were used to quantify MBG by analyzing the time course of contrast agent intensity rise. Hereby, the parameter G(max)/T(max) was calculated, derived from the plateau of grey-level intensity (G(max)), divided by the time-to-peak intensity (T(max)). Cardiac magnetic resonance imaging (CMR) deemed as the standard reference for the estimation of infarct size, transmurality and of the LV-function at 6 months of follow-up.

RESULTS

Cut-off values of G(max)/T(max)=5.7/sec and 3.8/sec, respectively, yielded similar accuracy as infarct transmurality for the prediction of follow-up ejection fraction >55% (AUC = 0.86 for STEMI and AUC = 0.90 for NSTEMI, by G(max)/T(max) and AUC = 0.85 for STEMI and AUC = 0.89 for NSTEMI, by infarct transmurality, respectively, P = NS). Both clearly surpassed the predictive value of visual MBG (AUC = 0.69 for STEMI and AUC = 0.68 for NSTEMI, P < 0.05).

CONCLUSION

G(max)/T(max) is an easy to acquire but highly valuable surrogate parameter for infarct size, which yields equally high accuracy with infarct transmurality and favorably compares with visually assessed blush grades for the prediction of follow-up LV-function in patients with acute ischemic syndromes.

Staged heart transplantation and chemotherapy as a treatment option in patients with severe cardiac light-chain amyloidosis

AIMS

The prognosis of advanced cardiac light-chain amyloidosis is poor. Heart transplantation might enable causative therapy and ultimately improve prognosis.

METHODS AND RESULTS

Nineteen patients with cardiac amyloidosis but no obvious involvement of other organs were scheduled for heart transplantation. Four to 6 months later, high-dose melphalan chemotherapy and autologous stem cell transplantation (HDM-ASCT) was planned in patients not in complete remission. Seven of nineteen patients died while waiting for heart transplantation. The remaining 12 patients (complete remission, n = 4) underwent surgery. Chemotherapy in patients not in complete remission consisted of HDM-ASCT (n = 5/12; subsequent complete remission, n = 2; partial remission, n = 3) or melphalan-prednisolone (partial remission, n = 1). Two of twelve patients were ineligible for any chemotherapy. Three of twelve patients died [423.5 (105-2131) days] from progressive disease, relapse, or sepsis. The 1- and 3-year survival rates were 83 and 83%, respectively, similar to those of patients undergoing heart transplantation for standard indications. Corresponding survival rates stratified by haematological response were 100 and 100% for complete remission (partial remission, 100 and 100%; progressive disease, 0 and 0%).

CONCLUSION

Heart transplantation in advanced cardiac amyloidosis is a promising approach to interrupting the vicious circle of ineligibility for potential curative chemotherapeutic treatment and extremely poor prognosis of cardiac amyloidosis without chemotherapy. Highly urgent heart transplantation combined with subsequent HDM-ASCT appears to offer a successful treatment option to improve the poor outcome of cardiac amyloidosis. However, it should be restricted to highly selected patients in specialized centres.

Effects of protein A immunoadsorption in patients with advanced chronic dilated cardiomyopathy

OBJECTIVES

The objective of this study was to investigate functional effects of immunoadsorption (IA) in severely limited study patients with chronic nonfamilial dilated cardiomyopathy (DCM), and to analyze the prevalence of Troponin I (TNI) autoantibodies.

BACKGROUND

Immunoadsorption (IA) has been shown to induce early hemodynamic improvement in patients with nonfamilial DCM.

METHODS

We performed IA using Immunosorba columns on five consecutive days in 27 patients with chronic DCM, congestive heart failure of NYHA class >or=II, left ventricular ejection fraction below 40%, and mean time since initial diagnosis of 7.2 +/- 6.8 years.

RESULTS

Immediately after IA, IgG decreased by 87.7% and IgG3 by 58.5%. Median NT-pro BNP was reduced from 1740.0 ng/L at baseline to 1504.0 ng/L after 6 months (P = 0.004). Mean left ventricular ejection fraction (LVEF) was not significantly improved overall (24.1 +/- 7.8% to 25.4 +/- 10.4% after 6 months, P = 0.38), but LVEF improved >or=5% (absolute) in 9 of 27 (33%) patients. Bicycle spiroergometry showed a significant increase in exercise capacity from 73.7 +/- 29.4 Watts to 88.8 +/- 31.1 Watts (P = 0.003) after 6 months while VO2max rose from 13.7 +/- 3.8 to 14.9 +/- 3.0 mL/min kg after 6 months (P = 0.09). Subgroup analysis revealed a higher NT-pro BNP reduction in patients with shorter disease duration (P = 0.03) and without TNI autoantibodies at baseline (P = 0.05). All 9 patients with an absolute increase of LVEF of >or=5.0% were diabetic (P = 0.0001).

CONCLUSIONS

In this study, on severely limited heart failure patients with nonfamilial DCM, IA therapy moderately improved markers of heart failure severity in a limited subgroup of patients. This may be due to the selected study population with end-stage heart failure patients and the lower reduction of IgG3 compared to previous studies. Future blinded multicenter studies are necessary to identify those patients that benefit most.

Evaluation cardioprotective effects of atorvastatin in rats by real time myocardial contrast echocardiography

BACKGROUND

The ability to assess myocardial perfusion in small animals is important, especially to investigate models of myocardial ischemia. Myocardial perfusion is usually assessed by postmortem techniques, eliminating the possibility of follow-up in intervention studies. The purpose of the study was to examine the feasibility of real time myocardial contrast echocardiography (MCE) to evaluate cardioprotective effects of atorvastatin in a rat model of acute ischemia-reperfusion injury.

METHODS

The rats (n=15) underwent 20 minutes of mechanical left descending coronary artery (LAD) occlusion followed by 180 minutes of reperfusion. The animals received either atorvastatin (10 mg/kg), atorvastatin and the nitric oxide synthase (NOS)-inhibitor N-Nitro-L-Argininemethylester (L-NAME) (15 mg/kg), or vehicle. MCE was performed to assess the size of the perfusion defect and the myocardial signal intensities (A(max)) at the baseline, during occlusion, and during reperfusion. For comparison, the infarct size, risk area, and regional myocardial blood flow (MBF) were determined by the standard techniques as well.

RESULTS

The dynamics of ischemia-reperfusion injury could be visualized serially by MCE. The infarct size-to-risk area ratio progressively increased during reperfusion and was markedly reduced in the atorvastatin group. Triphenyltetrazolium chloride (TTC) staining confirmed a 23% reduction in the infarct size by atorvastatin. The infarct size by MCE correlated well with the histological methods (r=0.86, P < 0.001). A(max) was reduced in the anterior segments during LAD occlusion (0.08 +/- 0.01 dB) compared to the baseline (2.9 +/- 0.4 dB), approached higher levels post revascularization of LAD (3.22 +/- 0.50 dB), but decreased during 180 minutes of reperfusion (2.32 +/- 0.40 dB). After 180 minutes of reperfusion, A(max) in the risk area was significantly higher in the atorvastain-treated group compared to the vehicle-treated group (2.32 +/- 0.40 dB vs 1.3 +/- 0.4 dB, P <or= 0.05), indicating preserved MBF. The L-NAME-treated group showed no significant difference compared to the vehicle-treated group (A(max) 1.12 +/- 0.60 dB vs 1.3 +/- 0.4 dB). The regional blood flow ratio (ischemic-to-nonischemic wall) measured by the microspheres was significantly higher in the atorvastatin group compared to the control and the L-NAME groups, respectively (0.92 +/- 0.13 vs 0.45 +/- 0.23 vs 0.51 +/- 0.16, P <or= 0.05).

CONCLUSIONS

Atorvastatin has cardioprotective effects in acute reperfusion injury. Contrast echocardiography allows visual and quantitative evaluation of the dynamics of myocardial ischemia-reperfusion injury and can be used to monitor cardioprotective effects during pharmacological interventions even in small animals.

Intravenous delivery of autologous mesenchymal stem cells limits infarct size and improves left ventricular function in the infarcted porcine heart

Systemic delivery of bone marrow-derived mesenchymal stem cells (MSCs) is a noninvasive approach for myocardial repair. We aimed to test this strategy in a pig model of myocardial infarction. Pigs (n = 8) received autologous MSCs (1 x 10(6)/kg body weight) labeled with fluorescent dye 48 h post proximal left anterior descending artery (LAD) occlusion. Hemodyamics, infarct size, and myocardial function were assessed at baseline and after 1 month. Morphologic analysis revealed that labeled MSCs migrated in the peri-infarct region, resulting in smaller infarct size (32 +/- 7 vs. 19 +/- 7%, p = 0.01), higher fractional area shortening (23 +/- 3 vs. 34.0 +/- 7%, p = 0.001), lower left ventricular end diastolic pressure (18.7 +/- 5 vs. 10.2 +/- 4 mmHg, p = 0.02) and higher +dp/dt (4,570 +/- 540 vs. 6,742 +/- 700 mmHg/s, p = 0.03) during inotropic stimulation. Systemic intravenous delivery of MSCs to pigs limits myocardial infarct size and is an attractive approach for tissue repair.

Quantitative evaluation of myocardial blush to assess tissue level reperfusion in patients with acute ST-elevation myocardial infarction: incremental prognostic value compared with visual assessment

BACKGROUND

Tissue level reperfusion gauges functional recovery in acute ischemic syndromes. However, its current clinical assessment is based upon visual interpretation of myocardial blush grade (MBG), which is operator dependent. The purpose of the study was to test whether quantification of MBG can enhance the predictive value of visual assessment for functional recovery in patients with acute ST-elevation myocardial infarction (STEMI).

METHODS

Myocardial blush grade was assessed in 124 consecutive patients with STEMI visually and quantitatively, analyzing the time course of blush intensity rise. We defined Gmax as the peak gray level intensity and Tmax as the time to peak intensity. Ejection fraction >50% at 4 to 6 months of follow-up was deemed as the primary end point for assessment of successful tissue reperfusion.

RESULTS

Ejection fraction >50% at follow-up was predicted by visual MBG with moderate sensitivity (65%) and specificity (64%). However, a cutoff value of Gmax/Tmax = 3.1/s yielded significantly higher sensitivity and specificity (91% and 96%, respectively, for both P < .01). Gmax/Tmax was the most powerful predictor of follow-up ejection fraction >50% (relative risk of 4.6 vs 3.2 for visual MBG).

CONCLUSIONS

Quantitative MBG is highly predictive for functional recovery in patients with STEMI and provides incremental prognostic value to visual assessment. Thus, this simple approach may be used to gauge reperfusion strategies in acute ischemic syndromes.

Liquefaction necrosis of mitral annulus calcification in a patient with chronic renal failure: an unrecognized diagnosis

Mitral annulus calcification is one of the most common cardiac calcifications. In patients with end-stage renal disease undergoing echocardiography, it can be detected in more than 40%. A specific form of mitral annulus calcification is liquefaction necrosis. It is often not adequately recognized by echocardiographers or clinicians and can be mistaken for cardiac tumor or infective vegetation. Here we report a case of liquefaction necrosis of mitral annulus calcification, mimicking an infective vegetation of the mitral valve apparatus in a patient with chronic renal failure.

Electrophoretic partitioning of proteins in two-phase microflows

This work reports on protein transport phenomena discovered in partitioning experiments with a novel setup for continuous-flow two-phase electrophoresis consisting of a microchannel in which a phase boundary is formed in flow direction. Proteins can be partitioned exploiting their affinity to different aqueous phases in two-phase systems. This separation process may be enhanced or extended by applying an electric field perpendicular to the phase boundary. In this context, microsystems offer new possibilities, as interfacial forces usually dominate over volume forces, thus allowing a superior control of the formation and arrangement of liquid/liquid phase boundaries. The two immiscible phases which are injected separately into the microchannel are taken from a polyethylene glycol (PEG)-dextran system. The side walls of the channel are partially made of gel material which serves as an ion conductor and decouples the channel from the electrodes, thus preventing bubble generation inside the separation channel. The experiments show that the electrophoretic transport of proteins between the laminated liquid phases is characterized by a strong asymmetry. When bovine serum albumin (BSA) is introduced into the PEG-rich phase, it can easily be transferred into the dextran-rich phase via an applied electric field of low strength or just by diffusion. In the reverse case, up to a certain field strength the transfer to the opposing phase is strongly inhibited. Only if the field strength is further increased will the BSA molecules leave the dextran-rich phase almost completely.

Electroosmotic flow patterning using microfluidic delay loops

A theoretical and experimental investigation of alternating electroosmotic flow patterns by means of specially designed delay loops is presented. Using elementary methods of compact network modeling and detailed FEM simulations the flow behavior and, in particular, the rearrangement of sample plugs is modeled. The proposed designs rely on flow splitting in combination with electroosmotic delay loops leading to a runtime difference or phase shift between two sub-streams. Due to this phase shift, a new fluid interface is generated at the merging point. The approach is experimentally validated by injection of a Rhodamine 6G solution into an aqueous sodium tetraborate buffer.

The potential of a new stable ultrasound contrast agent for site-specific targeting. An in vitro experiment

Microbubble-based ultrasound contrast agents can be used for specific site targeting, but demonstrate time-limited opacification. We have previously demonstrated the potential of gold-bound microtubules to provide a stable ultrasound contrast effect. Aim of the present study was to test the feasibility of gold-bound microtubules specifically to bind to human thrombi and to inflammatory activated human umbilical vein endothelial cells (HUVEC) in vitro. HUVEC were incubated with tumor necrosis factor, to induce expression of adhesion molecules. Human clots and HUVEC were incubated with biotinylated monoclonal antifibrin and anti-E-selectin antibodies, respectively. Probes were incubated with excess avidin followed by biotinylated gold-bound microtubules and by secondary Cy3-anti-beta-tubulin antibody and processed for immune fluorescence microscopy. Clots were transferred in copolymer foils filled with buffer and were ultrasonographically imaged before and after their treatment with the antifibrin antibody and with biotinylated microtubules, using a broadband harmonic transducer, transmitting and receiving at a mean frequency of 1.7 MHz and 3.2 MHz. The feasibility of specific gold-bound microtubules conjugation to antibody treated clots and HUVEC was confirmed using immune fluorescence analysis. Contrast intensities of the clots significantly increased after their treatment with antifibrin antibody and incubation with gold-bound microtubules (39 +/- 2 dB versus 26 +/- 2 dB, p < 0.001) and remained high after 20 min of ultrasound exposure (37 +/- 2 dB versus 39 +/- 2 dB, p = NS). Thus, gold-bound microtubules can specifically bind to human thrombi and to endothelial cells, providing a significant contrast effect which remains stable in the ultrasound field. This may be a promising approach to target thrombi and inflammatory active atherosclerotic plaques.

Real-time contrast-enhanced sonography of renal transplant recipients predicts chronic allograft nephropathy

Real-time contrast-enhanced sonography (RT-CES) can assess microvascular tissue perfusion using gas-filled microbubbles. The study was performed to evaluate the feasibility of RT-CES in detecting chronic allograft nephropathy (CAN) in comparison to color Doppler ultrasonography (CDUS). A total of 26 consecutive renal transplant recipients were prospectively studied using RT-CES and conventional CDUS. Transplant tissue perfusion imaging was performed by low-power imaging during i.v. administration of the sonocontrast Optison. Renal tissue perfusion was assessed quantitatively using flash replenishment kinetics of microbubbles to estimate renal blood flow A *beta (A = peak signal intensity, beta= slope of signal intensity rise). In contrast to conventional CDUS resistance and pulsatility indices, renal blood flow estimated by CES was highly significant related to S-creatinine (r =-0.62, p = 0.0004). Determination of renal blood flow by CES reached a higher sensitivity (91% vs. 82%, p < 0.05), specificity (82% vs. 64%, p < 0.05) and accuracy (85% vs. 73%, p < 0.05) for the diagnosis of CAN as compared to conventional CDUS resistance indices. Perfusion parameters derived from RT-CES significantly improve the early detection of CAN compared to conventional CDUS. RT-CES using low-power real-time perfusion imaging is a feasible method to evaluate microvascular perfusion in renal allograft recipients.

Real-time myocardial perfusion imaging for pharmacologic stress testing: added value to single photon emission computed tomography

BACKGROUND

Little is known about the incremental value of real-time myocardial contrast echocardiography (MCE) as an adjunct to pharmacologic stress testing. This study was performed to evaluate the diagnostic value of MCE to detect abnormal myocardial perfusion by technetium Tc 99m sestamibi-single photon emission computed tomography (SPECT) and anatomically significant coronary artery disease (CAD) by angiography.

METHODS

Myocardial contrast echocardiography was performed at rest and during vasodilator stress in consecutive patients (N = 120) undergoing SPECT imaging for known or suspected CAD. Myocardial opacification, wall motion, and tracer uptake were visually analyzed in 12 myocardial segments by 2 pairs of blinded observers. Concordance between the 2 methods was assessed using the kappa statistic.

RESULTS

Of 1356 segments, 1025 (76%) were interpretable by MCE, wall motion, and SPECT. Sensitivity of wall motion was 75%, specificity 83%, and accuracy 81% for detecting abnormal myocardial perfusion by SPECT (kappa = 0.53). Myocardial contrast echocardiography and wall motion together yielded significantly higher sensitivity (85% vs 74%, P < .05), specificity of 83%, and accuracy of 85% (kappa = 0.64) for the detection of abnormal myocardial perfusion. In 89 patients who underwent coronary angiography, MCE and wall motion together yielded higher sensitivity (83% vs 64%, P < .05) and accuracy (77% vs 68%, P < .05) but similar specificity (72%) compared with SPECT for the detection of high-grade, stenotic (> or = 75%) coronary lesions.

CONCLUSION

Assessment of myocardial perfusion adds value to conventional stress echocardiography by increasing its sensitivity for the detection of functionally abnormal myocardial perfusion. Myocardial contrast echocardiography and wall motion together provide higher sensitivity and accuracy for detection of CAD compared with SPECT.

Usefulness of myocardial parametric imaging to evaluate myocardial viability in experimental and in clinical studies

OBJECTIVE

To evaluate whether myocardial parametric imaging (MPI) is superior to visual assessment for the evaluation of myocardial viability.

METHODS AND RESULTS

Myocardial contrast echocardiography (MCE) was assessed in 11 pigs before, during, and after left anterior descending coronary artery occlusion and in 32 patients with ischaemic heart disease by using intravenous SonoVue administration. In experimental studies perfusion defect area assessment by MPI was compared with visually guided perfusion defect planimetry. Histological assessment of necrotic tissue was the standard reference. In clinical studies viability was assessed on a segmental level by (1) visual analysis of myocardial opacification; (2) quantitative estimation of myocardial blood flow in regions of interest; and (3) MPI. Functional recovery between three and six months after revascularisation was the standard reference. In experimental studies, compared with visually guided perfusion defect planimetry, planimetric assessment of infarct size by MPI correlated more significantly with histology (r2 = 0.92 versus r2 = 0.56) and had a lower intraobserver variability (4% v 15%, p < 0.05). In clinical studies, MPI had higher specificity (66% v 43%, p < 0.05) than visual MCE and good accuracy (81%) for viability detection. It was less time consuming (3.4 (1.6) v 9.2 (2.4) minutes per image, p < 0.05) than quantitative blood flow estimation by regions of interest and increased the agreement between observers interpreting myocardial perfusion (kappa = 0.87 v kappa = 0.75, p < 0.05).

CONCLUSION

MPI is useful for the evaluation of myocardial viability both in animals and in patients. It is less time consuming than quantification analysis by regions of interest and less observer dependent than visual analysis. Thus, strategies incorporating this technique may be valuable for the evaluation of myocardial viability in clinical routine.

Real-time myocardial contrast echocardiography for the detection of stress-induced myocardial ischemia. Comparison with 99mTc-sestamibi single photon emission computed tomography

BACKGROUND

Real-time contrast echocardiography (MCE) is a new promising technique for assessing myocardial perfusion. The purpose of this study was to test whether realtime MCE can be used to detect functionally significant coronary artery stenosis in patients with known or suspected coronary artery disease. Myocardial contrast echocardiographic studies were compared with nearly simultaneous 99mTc-sestamibi single photon emission computed tomography (SPECT) as a clinical standard reference to evaluate regional myocardial perfusion defects.

METHODS

Real-time MCE based on continuous infusion of Optison (8-10 ml/h) was performed in 66 patients during standard 99mTc-SPECT dipyridamole (0.56 mg/kg x 4 min) stress testing. Images were obtained in apical 4- and 2-chamber views, each divided into 6 segments. Tracer uptake and myocardial opacification were visually analyzed for each segment by two pairs of blinded observers and graded as normal, mildly reduced, severely reduced, or absent. In 792 myocardial segments, myocardial opacification by MCE was uninterpretable in 143 (18%) segments and tracer uptake by SPECT was not clearly defined in 92 (12%) segments. Interobserver variability for MCE was good with concordance rates of 83% (kappa=0.72) for rest- and 86% (kappa=0.76) for stress images. Overall concordance between MCE and SPECT was good (83%, kappa=0.63) at a segmental level. In the diagnosis of fixed and reversible defects, and of normal perfusion, concordance rates were 73, 65 and 83%, respectively. When analysis was performed at the regional level, we found comparable levels of concordance rates for LAD (83%, kappa=0.59), LCX (86%, kappa=0.64) and RCA (80%, kappa=0.68) perfusion territories.

CONCLUSIONS

These findings suggest that realtime MCE is a clinically acceptable method to evaluate myocardial perfusion defects during dipyridamole stress testing.