Sudden cardiac death in heart failure. A 20 years perspective from a Mediterranean cohort

Background

Although sudden cardiac death (SCD) has progressively decreased in the last decade, it remains an important cause of death in patients with heart failure (HF). Differences based on clinical management and regional characteristics might be important.

Purpose

To assess the prevalence of SCD along 20 years of study in HF outpatients of different aetiologies managed in a multidisciplinary HF Clinic, and compare this prevalence with the expected proportional occurrence according to the acknowledged Seattle Proportional Risk Model (SPRM) score.

Methods

In a prospective observational registry of real-life HF outpatients, modes of death were classified as SCD (any unexpected death, witnessed or not, of a previously stable patient with no evidence of worsening HF or any other known cause of death) and non-SCD (progression of HF, acute myocardial infarction, stroke, procedural, other cardiovascular causes and non-cardiovascular).

Results

From August 2001 to May 2021, 2772 outpatients with known cause of death and with SPRM score available were included. Out of them, 1351 (48.7%) died during a median follow-up of 3.8 years [IQR 1.6–7.8], up to 20 years. Observed prevalence of SCD in the 1351 dead patients was 13.6% while predicted SPRM prevalence was 39.6%. Annual SPRM predicted SCD mortality rate was 3.0% while observed SCD annual mortality rate was 1.3%. Figure 1 depicts cumulative incidence of causes of death through the study period. A lower prevalence of SCD was observed in every quintile of SPRM risk (Figure 2). This lower prevalence of SCD was observed independently of left ventricular ejection fraction group, ischemic or non-ischaemic aetiology and implantable cardiac defibrillator (ICD). Although the baseline SPRM predicted risk of SCD showed a significant decreasing trend (p=0.005) along the periods of admission at the Unit, the lower observed prevalence of SCD was seen in all periods of admission.

Conclusions

The prevalence of SCD through a perspective of 20 years in a Mediterranean HF outpatient cohort managed in a multidisciplinary HF Clinic was significantly lower than that expected according to the SPRM independently of degree of predicted risk, ischaemic aetiology, period of admission and implanted ICD. Regional lifestyle and dietary habits may have an impact on the lower rate of SCD in this Mediterranean cohort, and deserve further in-depth analyses.

Funding Acknowledgement

Type of funding sources: None.

How to screen frailty in outpatients with heart failure: multimodality assessment vs. the Vulnerable Elderly Survey 13 (VES-13) scale

Background

During two decades we have been screening fragility in outpatients with heart failure (HF) with a multimodality assessment using several geriatric scales, showing that frailty or fragility is frequent in HF patients, even in young patients, and we demonstrated that this identified fragility played an important prognostic role. Frailty is a medical syndrome with multiple causes and contributors that increases outpatients' vulnerability so a minimal stress can cause functional impairment, with a major risk of dependency, even death. Frailty can be reversible or attenuated by interventions. Nowadays several specific scales for fragility or frailty detection are widely available. One of them, the Vulnerable Elderly Survey 13 (VES-13) has scarcely been used in HF.

Purpose

To assess the prevalence of fragility in an outpatient HF Clinic at first visit using both the VES-13 scale and a multimodality assessment that includes Barthel index, OARS scale, Pfeiffer test, and abbreviated Yesavage Geriatric Depression Scale of 4 items (GDS), and compare the two approaches

Methods

Nurses fulfilled the scales with the patients at their first visit. An scoring ≥3 in the VES-13 scale and the presence of one of the predefined criteria in the multimodality assessment (Barthel <90; OARS score <10 in women and <6 in men; Pfeiffer Test score >3±1, depending on educational level; one positive depression response in abbreviated GDS; and age >85 years or nobody to turn to for help) were considered to have fragility for the purpose of the study.

Results

From March 2021 to December 2021, 136 patients were evaluated with the two fragility screening modalities (mean age 68.8±10.8 years, 64% men, 46% from ischaemic aetiology, 65.4%/27.9% in NYHA class II/III, LVEF 39.5% ± 13.4). VES-13 identified 51 (37.5%) patients with fragility, while the multimodality assessment detected 45 (33.6%) patients. Barthel index and depressive symptoms in the GDS were the most altered items (19 and 20 patients respectively) in the multimodality assessment. Concordance between VES-13 and multimodality assessment was 83.8%, but Cohen's Kappa was 0.65, not reaching the suitable level of 0.70.

Conclusions

VES-13 was capable of identifying a higher number of patients with fragility at first visit in the routine screening performed in an outpatient HF clinic, than the multimodality assessment used in the last decades. Follow-up of patients and further analysis will allow evaluating which of these two approaches adds more value for outcomes prediction.

Funding Acknowledgement

Type of funding sources: None.

Modelling Ecological Cognitive Rehabilitation Therapies for Building Virtual Environments in Brain Injury

BACKGROUND

Brain Injury (BI) has become one of the most common causes of neurological disability in developed countries. Cognitive disorders result in a loss of independence and patients' quality of life. Cognitive rehabilitation aims to promote patients' skills to achieve their highest degree of personal autonomy. New technologies such as virtual reality or interactive video allow developing rehabilitation therapies based on reproducible Activities of Daily Living (ADLs), increasing the ecological validity of the therapy. However, the lack of frameworks to formalize and represent the definition of this kind of therapies can be a barrier for widespread use of interactive virtual environments in clinical routine.

OBJECTIVES

To provide neuropsychologists with a methodology and an instrument to design and evaluate cognitive rehabilitation therapeutic interventions strategies based on ADLs performed in interactive virtual environments.

METHODS

The proposed methodology is used to model therapeutic interventions during virtual ADLs considering cognitive deficit, expected abnormal interactions and therapeutic hypotheses. It allows identifying abnormal behavioural patterns and designing interventions strategies in order to achieve errorless-based rehabilitation.

RESULTS

An ADL case study ('buying bread') is defined according to the guidelines established by the ADL intervention model. This case study is developed, as a proof of principle, using interactive video technology and is used to assess the feasibility of the proposed methodology in the definition of therapeutic intervention procedures.

CONCLUSIONS

The proposed methodology provides neuropsychologists with an instrument to design and evaluate ADL-based therapeutic intervention strategies, attending to solve actual limitation of virtual scenarios, to be use for ecological rehabilitation of cognitive deficit in daily clinical practice. The developed case study proves the potential of the methodology to design therapeutic interventions strategies; however our current work is devoted to designing more experiments in order to present more evidence about its values.

Cognitive neurorehabilitation based on interactive video technology

Cognitive impairment is the main cause of disability in developed societies. New interactive technologies help therapists in neurorehabilitation in order to increase patients' autonomy and quality of life. This work proposes Interactive Video (IV) as a technology to develop cognitive rehabilitation tasks based on Activities of Daily Living (ADL). ADL cognitive task has been developed and integrated with eye-tracking technology for task interaction and patients' performance monitoring.

White matter integrity related to functional working memory networks in traumatic brain injury

OBJECTIVE

This study explores the functional and structural patterns of connectivity underlying working memory impairment after severe traumatic axonal injury.

METHODS

We performed an fMRI n-back task and acquired diffusion tensor images (DTI) in a group of 19 chronic-stage patients with severe traumatic brain injury (TBI) and evidence of traumatic axonal injury and 19 matched healthy controls. We performed image analyses with FSL software and fMRI data were analyzed using probabilistic independent component analysis. Fractional anisotropy (FA) maps from DTI images were analyzed with FMRIB's Diffusion Toolbox.

RESULTS

We identified working memory and default mode networks. Global FA values correlated with both networks and FA whole-brain analysis revealed correlations in several tracts associated with the functional activation. Furthermore, working memory performance in the patient group correlated with the functional activation patterns and with the FA values of the associative fasciculi.

CONCLUSION

Combining structural and functional neuroimaging data, we were able to describe structural white matter changes related to functional network alterations and to lower performance in working memory in chronic TBI.

Overexpression of fructose 2,6-bisphosphatase decreases glycolysis and delays cell cycle progression

The ability to overexpress 6-phosphofructo-2-kinase/fructose 2, 6-bisphosphatase (PFK-2)/(FBPase-2) or a truncated form of the enzyme with only the bisphosphatase domain allowed us to analyze the relative role of the kinase and the bisphosphatase activities in regulating fructose 2,6-bisphosphate (Fru-2,6-P(2)) concentration and to elucidate their differential metabolic impact in epithelial Mv1Lu cells. The effect of overexpressing PFK-2/FBPase-2 resulted in a small increase in the kinase activity and in the activity ratio of the bifunctional enzyme, increasing Fru-2,6-P(2) levels, but these changes had no major effects on cell metabolism. In contrast, expression of the bisphosphatase domain increased the bisphosphatase activity, producing a significant decrease in Fru-2,6-P(2) concentration. The fall in the bisphosphorylated metabolite correlated with a decrease in lactate production and ATP concentration, as well as a delay in cell cycle. These results provide support for Fru-2,6-P(2) as a regulator of glycolytic flux and point out the role of glycolysis in cell cycle progression.

Cells overexpressing fructose-2,6-bisphosphatase showed enhanced pentose phosphate pathway flux and resistance to oxidative stress

Changes in the content of fructose-2,6-bisphosphate, a modulator of glycolytic flux, also affect other metabolic fluxes such as the non-oxidative pentose phosphate pathway. Since this is the main source of precursors for biosynthesis in proliferating cells, PFK-2/FBPase-2 has been proposed as a potential target for neoplastic treatments. Here we provide evidence that cells with a low content of fructose-2,6-bisphosphate have a lower energy status than controls, but they are also less sensitive to oxidative stress. This feature is related to the activation of the oxidative branch of the pentose phosphate pathway and the increased production of NADPH.

MPP(+)-induced mitochondrial dysfunction is potentiated by dopamine

MPP(+), the major metabolite of the Parkinsonism-inducing compound MPTP, responsible for the destruction of the nigrostriatal pathway in primates and rodents, has been assayed in isolated rat liver mitochondria in the presence of physiological concentrations of dopamine or analogous concentrations of melanin-dopamine. 5 microM MPP(+) in the presence of 70 microM dopamine or melanin-dopamine, but not alone, decreased the heat production and oxygen consumption of a mitochondrial suspension activated with succinate and ADP. Both dopamine and oxidized dopamine plus MPP(+) also decreased the mitochondrial reductive power measured with MTT. Mitochondrial swelling was observed, associated with an increase in membrane mitochondrial potential, as a synergistic effect between low concentrations of MPP(+) and dopamine. It is suggested that cytosolic dopamine, by itself or via its autooxidation products, may play a relevant role in the mitochondrial toxicity of MPP(+). A failure in the regulation of the storage/release of dopamine could aggravate a mitochondrial damage and trigger the neurodegenerative process underlying MPTP toxicity and Parkinson's disease.

Na(+)-K(+) pump and metabolic activities of trout erythrocytes during anoxia

Metabolic activity in the red blood cells of brown trout was monitored under conditions of oxygen depletion and chemically induced anoxia. Although metabolic activity was reduced during anoxia to one-third of the normoxic value, these cells maintained their ATP contents stable and were viable for hours in the absence of oxygen. In addition, Na(+)-K(+) pump activity was not down-regulated when metabolic activity was reduced during anoxia. The compatibility of this finding with energy equilibrium and ion homeostasis was investigated.

Exogenous fructose 1,6-bisphosphate reduces K+ permeability in isolated rat hepatocytes

The relationship between the protective effect of fructose 1,6-bisphosphate (F-1,6-P2) against cell injury and the modifications produced in the metabolic fluxes and in the membrane permeability to K+ was studied in isolated rat hepatocytes. Incubation of these cells in the presence of F-1,6-P2 reduced metabolic activity without affecting the ATP content, which suggests a downregulation of the ATP turnover. Using 86Rb+ as a tracer, we analyzed the relationship between these metabolic changes and alterations in K+ fluxes. In the presence of F-1,6-P2 the passive and the active K+ fluxes in hepatocytes decreased. However, the Na(+)-K+ pump from semipurified membranes was not directly affected by F-1,6-P2, which suggests a secondarily induced reduction of Na(+)-K+ pump activity. Moreover, galactosamine-treated cells showed a marked increase in permeability to K+ that was abolished by the presence of F-1,6-P2. This protective effect may be related to the prevention of K+ efflux. The results reported here strongly suggest the induction of channel arrest, and the associated metabolic downregulation, as the primary protective effect of F-1,6-P2, as has been shown in the prevention of galactosamine-induced hepatotoxicity.

Serum-liposome interaction is an oxygen-dependent process

Measurements of heat dissipation, oxygen concentration and average vesicle size were correlated to study the effect of serum components on different types of liposome. The results indicate that the interaction between serum components and liposomes is exothermic and oxygen dependent, and leads to disruption of vesicles. The dependence of this effect on serum concentration, vesicle surface charge and type of liposome was also evaluated. Serum components did not produce any effect on conventional liposomes in the absence of oxygen. Moreover, in hypoxic conditions the serum-liposome interaction was delayed. Both results suggest that this interaction is an oxygen-dependent event. Finally, we confirmed that sterically stabilised liposomes remain unalterated in the presence of serum.

Adrenergic stimulation of sea bream (Sparus aurata) red blood cells in normoxia and anoxia: effects on metabolism and on the oxygen affinity of haemoglobin

The metabolic response of sea bream (Sparus aurata) red blood cells to adrenergic stimulation was determined in normoxia and anoxia. In the presence of oxygen, red blood cells swelled and then recovered their resting volume. Continuous monitoring of oxygen uptake displayed the kinetics of the increase in the oxygen affinity of haemoglobin. Cell volume recovery correlated with an activation of ATP consumption, and the energy equilibrium was restored by increasing the rates of respiration and glycolysis. When the respiratory chain was blocked, adrenergic stimulation increased the rates of ATP consumption and glycolysis of red blood cells. Moreover, adrenergic stimulation of deoxygenated erythrocytes also increased cell volume but did not enhance glycolysis or ATP consumption, and the cells remained swollen. Our results suggest that there is an oxygen-linked signal transducer that activates ATP-consuming processes, provided that the adrenergic stimulation occurs in the presence of oxygen.

Early effects of basic fibroblast growth factor on foetal rat mesencephalic cell suspensions

Mesencephalic cell suspensions are used, experimentally but also clinically, to compensate for neurological deficiencies, by implantation into the striatum. Here, we have studied the metabolism of mesencephalic cell suspensions obtained from rat embryos by measuring heat dissipation, oxygen consumption, ATP and lactate production. The effect of basic fibroblast growth factor (bFGF) at a 50 ng/ml concentration on these parameters was studied in order to assess the effect of in vitro exposure of cell suspensions to this trophic factor. Heat production and oxygen consumption were low, as could be expected from an immature nervous tissue, and they further decreased after addition of bFGF. This trophic factor decreased the total ATP concentration and increased the lactate production. The viability of the cell suspensions was reduced by nearly a half, 2 h after the addition of bFGF, and numerous fragmented nuclei were observed. It seems that, in contrast to the neuroprotective effect of bFGF on mesencephalic cultures and nigrostriatal neurons, this factor could have an initial sorting effect in the development of mesencephalic structures.

Effects of taxol on isolated rat hepatocyte metabolism

Taxol is a natural product, isolated from Taxus brevifolia, with increasing clinical applications because of its potent antitumor activity. Although it is mainly metabolized in the liver, its effect on hepatocyte metabolism has been scarcely investigated. In this study, the response of isolated rat hepatocytes to taxol was evaluated by correlating the changes observed in global indexes such as viability and heat dissipation with those produced in oxygen consumption and intracellular metabolites (ATP, fructose 2,6-bisphosphate, and lactate). The results indicate that taxol reduces aerobic metabolism, which induces an insufficient increase of the ATP via anaerobic glycolysis. Moreover, incubations of isolated mitochondria with taxol indicate that the respiratory chain is directly affected by this drug.

Microcalorimetric evaluation of the effect of combined chemotherapeutic drugs

A study of the effect of combined antineoplastic drugs in vitro was carried out by microcalorimetric monitoring of the metabolic activity of treated cells. Power-time curves of growing T-lymphoma cell suspensions, treated with single or combined drugs, were recorded. The extent of the effect was evaluated by changes in the slopes of the microcalorimetric curves and the kinetics of the drug action were interpreted from the time at which these changes reached their maximum value. The method was validated using two well-established drug combinations, the potentiatory effect of dipyridamole on methotrexate cytotoxicity, and the synergism between methotrexate and 6-thioguanine. In the first case, where one drug is not toxic, the modulation may be evaluated by comparing the inhibition produced by the toxic drug alone and in combination with its modulator. Otherwise, when both drugs are toxic, the combined effect must be evaluated by means of their combination index. The measurement procedure is simple, the electric signal is well suited to automation of data acquisition and the response may be evaluated within 5 to 6 h of drug administration. Moreover, we demonstrate that microcalorimetry is a reliable method for the detection of modulatory effects in combination chemotherapy.

Intracavernous pharmacotherapy for management of erectile dysfunction in multiple sclerosis patients

Intracavernous self-injection of vasoactive drugs is a well accepted therapy for the management of erectile dysfunction in neurogenic disorders. We present the results of a self-injection program in seven MS patients who were admitted in Institut Guttmann of Barcelona and who presented with an insufficient erection. All patients showed an excellent erectile response and had penile rigidity sufficient for sexual intercourse during acceptable time, with minimal complications. A patient reported improvement of erectile capacity so as not to need another cavernously injection for 2-3 months.

ENERGY METABOLISM BY TROUT RED BLOOD CELLS: SUBSTRATE UTILISATION

The present study investigates energy metabolism by trout red blood cells. It is shown that they are able to use pyruvate at physiological concentrations as an aerobic source of energy. Moreover, microcalorimetric data suggest that trout erythrocytes are also able to use internal substrates, at least when maintained in vitro. Although the actual nature of these substrates has not been elucidated, glycogen appears to be the most probable. The relationship between heat dissipation and oxygen consumption suggests that most of the oxygen is used to oxidize substrates, and the inhibition of respiratory activity by antimycin A indicates that there is no substantial utilisation of non-respiratory oxygen. However, the oxygen uptake by these cells does not appear to be related to substrate utilisation, measured from transformation of labelled molecules (either pyruvate or glucose); this may be due to mixing of labelled compounds with non-labelled molecules in the intracellular pools, because of the low metabolic rate of these cells.

Fructose 1,6-bisphosphate protects against D-galactosamine toxicity in isolated rat hepatocytes

Incubation of hepatocytes with D-galactosamine (GalN) produced a dose-dependent alteration in cell viability and a fall in ATP and fructose 2,6-bisphosphate (Fru-2,6-P2) levels. The reduction in Fru-2,6-P2 can be explained by changes in the substrates or modulators of 6-phosphofructo-2-kinase/fructose 2,6-bisphosphatase, because neither the adenosine 3',5'-cyclic monophosphate level nor the activity ratio of the enzyme was modified. Microcalorimetric measurements showed that GalN produced an exothermic peak followed by a progressive decrease in heat dissipation. Simultaneous administration of GalN and fructose 1,6-bisphosphate (Fru-1,6-P2) significantly increased cell viability, and concentrations of ATP and Fru-2,6-P2 and led to stable heat production. In the presence of Fru-1,6-P2 alone, hepatocytes kept ATP and Fru-2,6-P2 levels constant, whereas they increased the oxygen uptake-to-heat output ratio. Our results suggest that GalN initiates the hepatotoxic effect by means of an energy-dissipating interaction, produced before its metabolism and presumably at the membrane level, whereas Fru-1,6-P2 protects the cells against this injury in a way that prevents the initial interaction and increases the metabolic efficiency of the cell.

Double luminal and vascular perfusion of chicken jejunum: studies on 3-O-methyl-D-glucose absorption

The aims of the present study were: (1) to set up a procedure for simultaneous vascular and luminal perfusion of the chicken jejunum; (2) to assess the transport capacity of the tissue under such conditions, and (3) to study the effects of phloretin and theophylline, given through the vascular perfusate, on 3-O-methyl-D-glucose intestinal transport. The perfusion procedure described allowed the control of intestinal and vascular inflow rates and perfusion pressures so that these parameters could be adjusted to physiological values. A perfluorochemical emulsion was used as oxygen carrier for the vascular perfusate. The absorptive function of the perfused tissue was assessed by means of its ability to transport 3-O-methyl-D-glucose. Furthermore, ultrastructure preservation was evaluated by scanning and transmission electron microscopy. Results indicate that the perfused tissue kept its transport capacity and morphology intact throughout the 120-min experimental period. Moreover, no hypersecretion was observed as indicated by the constancy of perfusate volumes and perfusion pressures. Phloretin (1 mM) or theophylline (10 mM) added to the vascular perfusate markedly reduced the transfer of 3-O-methyl-D-glucose from the enterocyte to the vascular fluid without affecting the uptake from the lumen. Our results suggest that this preparation may be used as an alternative tool for the study of intestinal absorption processes in avian species, particularly when complete examination is required of the efflux of substrates from the intestinal lumen to the vascular fluid.

Intestinal perfusion in vivo for the study of absorptive processes

1. Intestinal absorption can be studied by in vitro and in vivo techniques. Among the in vivo ones, intestinal perfusion is the one more employed. 2. Intestinal perfusion could be performed by a simple perfusion of an intestinal segment or by a double perfusion of the intestine and the vascular bed simultaneously. 3. The double perfusion has the advantage of measuring the substrate appearance in the vascular circuit. 4. In this review we compare the different techniques described in the literature, paying attention to their advantages. 5. The best method is the one that maintains the animal alive throughout the experiment, because it provides information about intestinal absorption under conditions similar to the natural ones.