Exercise capacity in patients implanted with left ventricular assist devices for end-stage heart failure treatment

Funding Acknowledgements

Type of funding sources: None.

Introduction

Left ventricular assist device (LVAD) is an expanding therapy in end-stage heart failure today. Although LVAD therapy bears the potential to normalize cardiac output, a majority of patients show a severely impaired physical condition at the time of LVAD implantation. To date, no validated standardized training protocol is available, and established practices to effectively improve LVAD patients’ exercise tolerance is lacking. This study sought to investigate exercise capacity quantified by cardiopulmonary exercise testing (CPX) and a standardized six-minute walk test (6MWT) in patients after LVAD implantation.

Methods

We enrolled 30 end-stage heart failure patients who had received an LVAD implantation 20.7 ± 7.6 days prior to examination, mean age 54.9 ± 7.8 years, 26 males (87 %). Exercise tolerance was assessed using cardiopulmonary exercise testing (CPX) for maximal and submaximal exercise capacity, followed by a standardized (6MWT).

Results

Patients showed peak oxygen uptake values of 8.3 ± 2.4 ml/min/kg at a mean workload of 46.7 ± 11.3 watts and a mean anaerobic threshold of 6.7 ± 1.7 ml/min/kg at a workload of 32.6 ± 6.9 watts. Mean standardized 6-minute walking distance was at 183.8 ± 71.4 meters. There were no adverse events during exercise testing.

Conclusions

Cardiopulmonary exercise testing (CPX) and standardized 6MWT show severely impaired cardiopulmonary exercise capacity in patients after LVAD implantation, warranting further studies for dedicated training protocols, specifically focusing on LVAD patients to improve exercise tolerance at an acceptable safety profile.

P3825Long-term prognostic value of growth differentiation factor-15 in acute coronary syndrome

Introduction

Biomarkers plays a critical role in diagnostic, prognostication, and decision-making in cardiovascular medicine. Growth differentiation factor-15 (GDF-15) has been reported as a potential biomarker in acute coronary syndrome (ACS). However, there is limited data on the long-term prognostic value after an ACS.

Purpose

To study the long-term prognostic value of GDF-15 in ACS.

Methods

We included patients with ACS who underwent coronary angiography. During angiography an arterial blood sample was collected. Plasma GDF-15 were measured and clinical data and long-term events were obtained. As previously reported, risk categories were defined as low risk (<1200ng/L), intermediate (1200–1800ng/L) and high risk (>1800ng/L). Incremental prognostic value of GDF-15 for all-cause death was assessed on top of a clinical model (GRACE score, LVEF<40% and age).

Results

A total of 358 patients were included; 157 as a low risk, 85 as an intermediate and 116 as a high risk. The median (IQR) age was 65 (56–74) years and 27.4% were female. Of all patients, 61.5% were admitted with non-ST-elevation myocardial infarction, 24.0% with ST-elevation myocardial infarction and 14.5% with unstable angina. Higher values of GDF-15 were consistently associated with an increased prevalence of cardiovascular risk factors. During 6 years of follow-up 54 patients died. Of those patients, 7 (4.5%) had values of GDF-15 below 1200ng/L, 6 (7.1%) between 1200–1800ng/L and 41 (35.3%) above 1800ng/L. After adjustment for a multivariate Cox regression model, GDF-15 >1800ng/L were independently associated with all-cause death (HR 4.5; 95% CI 1.8–11.6; p=0.002) and the composite of major adverse cardiovascular events (MACE) which were identified as all-cause death, nonfatal MI and heart failure (HR 2.5; 95% CI 1.4–4.4; p=0.001). For long-term all-cause death a significant increase of the c-statistic was seen after addition of GDF-15 to the clinical model 0.871 (95% CI 0.817–0.924; p=0.019) as well as net reclassification improvement (0.769; 95% CI 0.487–1.051; p<0.001) and integrated discrimination improvement (0.117; 95% CI 0.062–0.172; p<0.001). Of 18 events of heart failure, 17 occurred in patients with GDF>1800ng/L. A multivariate competing risk model showed a significant association between GDF-15>1800ng/L and incidence of heart failure (adjusted HR 30.8; 95% CI 4.1–231.5; p=0.001) but non-significant association were found for myocardial infarction.

KM figures and all-cause death ROC curve

Conclusions

In the setting of ACS GDF-15 can predict long-term all-cause death, MACE and heart failure and provides incremental prognostic value beyond traditional risks factors in the long-term all-cause death.

P6437Growth differentiation factor-15 and stromal cell-derived factor-1 as long-term prognosis biomarkers in acute coronary syndrome

Introduction

After an acute coronary syn bdrome (ACS) patients are at high risk of cardiovascular morbidity and mortality. In this scenario, Growth differentiation factor-15 (GDF-15) and Stromal cell derived factor-1 (SDF-1) has been reported as potential biomarkers in ACS. However, there is limited data about their combined use in long-term prognosis.

Purpose

To study the long-term prognostic value of GDF-15 and SDF-1 in ACS.

Methods

We included patients with ACS who underwent coronary angiography. During angiography an arterial blood sample was collected. Plasma SDF-1 and GDF-15 were measured and clinical data and long-term events were obtained. The cut-off point of SDF-1 and GDF-15 was identified individually by receiver operating characteristic curves. Patients were classified into 3 groups: 1) both biomarkers below cut-off points; 2) only one biomarker above cut-off points; 3) both biomarkers above cut-off points.

Results

A total of 238 patients were included. The median (IQR) age was 64 (55–74) year and 27.3% were female. Of all patients, 60.9% were admitted with non-ST-elevation myocardial infarction, 22.7% with ST-elevation myocardial infarction and 16.4% with unstable angina. The cut-off point of SDF-1 was 3283.5pg/mL and GDF-15 was 1849ng/L. A total of 127 patients were in group 1, 64 in group 2 and 47 in group 3. Group 3 patients were associated with older age, hypertension, dyslipidemia, diabetes mellitus and history of myocardial infarction (MI), stroke, chronic kidney disease and peripheral artery disease. Besides, they were more likely to have left ventricular dysfunction (ejection fraction <40%) and significant three vessels stenosis. During 6.5 years of follow-up 8 patients died (6.3%) in group 1, 7 patients died (10.9%) in group 2 and 25 patients died (53.2%) in group 3 (Figure 1). Multivariate Cox analysis showed that high levels of SDF-1 and GDF-15 (group 3) were an independent predictor of all-cause death (HR 5.8; 95% CI 2.4 - 14.1; p<0.001) and the composite of major adverse cardiovascular events (MACE) which were identified as all-cause death, nonfatal MI and heart failure (HR 3.9; 95% CI 2.1 - 7.3; p<0.001). During follow-up 1 patient had heart failure in group 1 (0.8%), 3 patients (4.7%) in group 2 and 9 patients (19.1%) in group 3. Despite the low number of events of heart failure, the multivariate competing risks regression showed association between group 3 and heart failure during follow-up (HR 28.0; 95% CI 3.5 - 225.2; p=0.002). Higher levels of SDF-1 and GDF-15 (group 3) were not associated with new MI in multivariate competing risks regression. Regarding group 2, all multivariate analyses were non-significant.

Cumulative survival and incidence curves

Conclusions

Higher values of combined GDF-15 and SDF-1 are an excellent predictor of all-cause death, MACE and heart failure in long-term follow-up of patients with ACS. The combined use of SDF-1 and GDF-15 may be useful in long-term ACS prognosis.

[Heart failure: ventricular assist devices and cardiac transplantation : A review of current surgical innovations]

BACKGROUND

End-stage heart failure is one of the leading causes of death in Germany. Cardiac transplantation is still considered the gold standard for the treatment of terminal heart failure; however, there is a discrepancy between patients on the waiting list and yearly performed transplantations. As an alternative, ventricular assist devices have achieved a high level of importance but treatment is still associated with challenges. Novel systems as well as innovative surgical techniques contribute to improving the safety and effectiveness of the treatment.

OBJECTIVE

To generate an overview of current surgical innovations in cardiac transplantation and mechanical circulatory support.

MATERIAL AND METHODS

A Medline search was conducted regarding innovations in cardiac transplantation and mechanical circulatory support.

RESULTS AND CONCLUSION

Not only the number of yearly performed cardiac transplantations has changed but also recipient profiles. While in the pioneering era of transplantation the typical candidate was young, not previously operated on and with lower levels of comorbidities, today's patients are significantly older, have been fitted with ventricular assist devices and have increased operative risk profiles. Modern methods of organ preservation enable longer transportation and operation times as well as an improved assessment of graft function and perspectives for graft optimization in the future. In the area of ventricular assist devices, advances in the reduction of the stroke rate seem to have been achieved by the latest generation devices. From a surgical perspective, less invasive surgical techniques with promising initial results have been established at numerous centers.

Metal organic frameworks based on bioactive components

This review highlights the latest advances of Metal Organic Frameworks (MOFs) in the promising biomedical domain, from their synthesis to their biorelated activities.

One-pot preparation of a novel CO-releasing material based on a CO-releasing molecule@metal–organic framework system

A hierarchical micro-mesoporous metal–organic framework has been used as a platform of a photoactivable CO-prodrug to prepare a novel CO-releasing material.

Nonlinear cerebral atrophy patterns across the Alzheimer's disease continuum: impact of APOE4 genotype

The progression of Alzheimer's disease (AD) is characterized by complex trajectories of cerebral atrophy that are affected by interactions with age and apolipoprotein E allele ε4 (APOE4) status. In this article, we report the nonlinear volumetric changes in gray matter across the full biological spectrum of the disease, represented by the AD-cerebrospinal fluid (CSF) index. This index reflects the subject's level of pathology and position along the AD continuum. We also evaluated the associated impact of the APOE4 genotype. The atrophy pattern associated with the AD-CSF index was highly symmetrical and corresponded with the typical AD signature. Medial temporal structures showed different atrophy dynamics along the progression of the disease. The bilateral parahippocampal cortices and a parietotemporal region extending from the middle temporal to the supramarginal gyrus presented an initial increase in volume which later reverted. Similarly, a portion of the precuneus presented a rather linear inverse association with the AD-CSF index whereas some other clusters did not show significant atrophy until index values corresponded to positive CSF tau values. APOE4 carriers showed steeper hippocampal volume reductions with AD progression. Overall, the reported atrophy patterns are in close agreement with those mentioned in previous findings. However, the detected nonlinearities suggest that there may be different pathological processes taking place at specific moments during AD progression and reveal the impact of the APOE4 allele.

A new era of ventricular assist device surgery: less invasive procedures

As the number of patients suffering of congestive heart failure is rising worldwide, the use of mechanical circulatory support to treat these patients has also grown enormously, surpassing the number of annual heart transplants. Moreover latest generation of left ventricular assist devices (LVADs) is characterized by improved technologies. Moreover the size of new LVAD systems is considerably reduced when compared to older generation devices. Therefore, less invasive surgery is now possible for the implantation, explantation, and exchange of LVADs. Although experience with these new techniques is still limited, minimally invasive procedures are thought to improve surgical outcomes by declining the rates of operative complications such as bleeding or wound infection. The miniaturization of LVADs will continue, so that minimally invasive techniques will be used for most LVAD-related procedures in the future. In this article, we summarize and describe minimally invasive surgical techniques, with a focus on the most common LVAD systems in adults.

Development of a variable-radius pinhole SPECT system with a portable gamma camera

OBJECTIVE

To develop a small-animal SPECT system using a low cost commercial portable gamma camera equipped with a pinhole collimator, a continuous scintillation crystal and a position-sensitive photomultiplier tube.

MATERIAL AND METHODS

The gamma camera was attached to a variable radius system, which enabled us to optimize sensitivity and resolution by adjusting the radius of rotation to the size of the object. To investigate the capability of the SPECT system for small animal imaging, the dependence of resolution and calibration parameters on radius was assessed and acquisitions of small phantoms and mice were carried out.

RESULTS

Resolution values, ranging from 1.0mm for a radius of 21.4mm and 1.4mm for a radius of 37.2mm were obtained, thereby justifying the interest of a variable radius SPECT system.

CONCLUSIONS

The image quality of phantoms and animals were satisfactory, thus confirming the usefulness of the system for small animal SPECT imaging.

The effects of aging on dopaminergic neurotransmission: a microPET study of [11C]-raclopride binding in the aged rodent brain

Rodent models are frequently used in aging research to investigate biochemical age effects and aid in the development of therapies for pathological and non-pathological age-related degenerative processes. In order to validate the use of animal models in aging research and pave the way for longitudinal intervention-based animal studies, the consistency of cerebral aging processes across species needs to be evaluated. The dopaminergic system seems particularly susceptible to the aging process, and one of the most consistent findings in human brain aging research is a decline in striatal D2-like receptor (D2R) availability, quantifiable by positron emission tomography (PET) imaging. In this study, we aimed to assess whether similar age effects can be discerned in rat brains, using in vivo molecular imaging with the radioactive compound [(11)C]-raclopride. We observed a robust decline in striatal [(11)C]-raclopride uptake in the aged rats in comparison to the young control group, comprising a 41% decrement in striatal binding potential. In accordance with human studies, these results indicate that substantial reductions in D2R availability can be measured in the aged striatal complex. Our findings suggest that rat and human brains exhibit similar biochemical alterations with age in the striatal dopaminergic system, providing support for the pertinence of rodent models in aging research.

Testosterone stimulates progesterone production and STAR, P450 cholesterol side-chain cleavage and LH receptor mRNAs expression in hen (Gallus domesticus) granulosa cells

The chicken ovary is organized into a hierarchy of yellow yolky follicles that ovulate on successive days. Active or passive immunization of laying hens against testosterone blocks ovulation without affecting follicle development. Testosterone may play a role in pre-ovulatory follicle maturation by stimulating granulosa progesterone production. We assessed whether this stimulus is dose-related and depends on the maturity of the donor follicle, and if it does so by stimulating granulosa cell STAR, P450 cholesterol side-chain cleavage (P450scc), and LH receptor (LHCGR) mRNAs expression. Progesterone production by granulosa cells from F1, F3, and F4 follicles, cultured for 3 h without testosterone was greater in cells collected 11-14 h than 1-4 h after ovulation. These differences in progesterone production were less pronounced after granulosa cells had been cultured for 24 h. Culture of granulosa cells for 3 or 24 h with testosterone (1-100 ng/ml) stimulated progesterone production in cells collected from F4, F3, or F1 follicles 1-4, or 11-14 h after ovulation. Testosterone (0-4000 ng/ml) alone or in combination with LH (0-100 ng/ml) increased progesterone production by F1 granulosa cells, collected 1-4 and 11-14 h after ovulation and cultured for 3 h. Finally, testosterone (10 or 100 ng/ml) increased STAR, P450scc, and LHCGR mRNAs, when added to 3 h cultures of F1 granulosa cells. In conclusion, testosterone stimulates granulosa cell progesterone production in hen pre-ovulatory hierarchical follicles irrespective of maturational state, acting alone or additively with LH. We propose that testosterone promotes granulosa cell maturation to facilitate the pre-ovulatory release of LH.

Evaluation of six pesticides leaching indexes using field data of herbicide application in Casablanca Valley, Chile

A field study was performed to evaluate the accuracy of six pesticide screening leaching indexes for herbicide movement. Adsorption, dissipation and soil movement were studied in a vineyard in a sandy loam soil during 2005 season. Simazine, diuron, pendimethalin, oxyfluorfen and flumioxazin were applied to bare soil at rates commonly used, and their soil concentrations throughout soil profile were determined at 0, 10, 20, 40 and 90 days after application (DAA). Herbicides were subjected to two pluviometric regimens, natural field condition and modified conditions (plus natural rainfall 180 mm). Leaching indexes utilized were: Briggs's Rf, Hamaker's Rf, LEACH, LPI, GUS and LIX. Simazine reached 120 cm, diuron 90 cm, flumioxazin 30 cm soil depth respectively. Pendimethalin and oxyfluorfen were retained up to 5 cm. None of the herbicides leaching was affected by rainfall regimen. Only flumioxazin field dissipation was clearly affected by pluviometric condition. The best representation of the herbicide soil depth movement and leaching below 15 cm soil depth were: Hamaker's Rf < Briggs's Rf < GUS < LPI, < LEACH < LIX. Field results showed a good correlation between herbicides K(d) and their soil depth movement and mass leached below 15 cm soil depth.

Relevance in the Fischer−Tropsch Synthesis of the Formation of Fe−O−Ce Interactions on Iron−Cerium Mixed Oxide Systems

A series of Fe-Ce mixed oxides (95 atom % Fe-5 atom % Ce) has been prepared by different methods: coprecipitation, impregnation, and physical mixture of Ce and Fe oxides. These solids have been tested in the Fischer-Tropsch synthesis. The characterization of the catalytic precursors was carried out by X-ray diffraction (XRD), Raman, Mössbauer, and X-ray photoelectron (XPS) spectroscopic techniques. When the preparation method ensures a microscopic contact between Fe and Ce cations in the solid, several types of Fe-Ce interactions are present in the calcined solids. The interactions take the shape of Fe-O-Ce bridges that can exist either in the hematite-like solid solution or in the interphase between the Fe oxide covered by microcrystals of Ce oxide. In the case of the hematite-like solid solution, Ce(IV) cations are dissolved in the alpha-Fe2O3 network. The promotion by Ce of the catalytic properties observed in the final catalysts can be directly related with the detection of these Fe-O-Ce bridges in the calcined solids. The Ce promotion results in a larger yield to hydrocarbons, a higher production of olefins, and a higher selectivity to medium and large chain hydrocarbons (larger than six carbon atoms). It is proposed that the Ce promotion is due to the presence of Fe0-Ce(III) ensembles in the final catalysts arising from the initial Fe-O-Ce bridges developed in the parent calcined samples.