Long-term outcomes of a Caucasian cohort presenting with acute coronary syndrome and/or out-of-hospital cardiac arrest caused by coronary spasm.

BACKGROUND: Coronary artery spasm may be the underlying mechanism in up to 10% of cases of acute coronary syndrome (ACS) and sudden cardiac death. Asian individuals exhibit a 3-times greater incidence of spasm than Caucasians; this is likely due to different types of mechanisms. Consequently, solid data is limited about the long-term prognosis in Caucasian patients presenting with ACS and/or out-of-hospital cardiac arrest (OHCA) caused by coronary spasm. METHODS: Between 2002 and 2015, thirty Caucasian patients with coronary artery spasm presenting with ACS (N = 29) and/or OHCA (N = 11) were enrolled in this prospective registry. Follow-up, consisting of regular outpatient visits, was conducted with a mean follow-up period of 7.5 ± 3.3 years. Outcomes included presence of stable angina pectoris, recurrence of ACS, occurrence of implantable cardioverter defibrillator (ICD) shocks and death. RESULTS: The majority of patients (60%) remained asymptomatic during the entire follow-up period. At the end of the follow-up period only 3 patients still experienced stable angina (10%). Only 2 patients (7%) had a recurrent cardiac event, in which the ICD provided appropriate shock therapy. Half of the patients treated with stenting (N = 6), required re-interventions. CONCLUSION: Coronary spasm with ACS and/or OHCA in a Caucasian patient cohort has a relatively benign prognosis in the majority of patients in long-term follow-up, if treated appropriately with medical therapy. Both the role of ICD in OHCA secondary to coronary spasm, and the efficacy of stenting to treat vasospastic angina, warrant further study in large-sized prospective clinical trials.

The relationship between terminal QRS distortion on initial ECG and final infarct size at 4months in conventional ST- segment elevation myocardial infarct patients.

BACKGROUND: In the Sclarovsky-Birnbaum Ischemia Severity Grading System for patients with ST-segment elevation myocardial infarction (STEMI), "Terminal QRS distortion" is considered as "Grade III". This evidence for most severe ischemia is associated with cardiovascular magnetic resonance imaging (CMR) markers of myocardial damage in the subacute phase. Our aim was to assess whether terminal QRS distortions on the initial electrocardiogram (ECG) is predictive for infarct size (IS) and left ventricular ejection fraction (LVEF) at 4months in anterior versus infarct locations. METHODS: Patient data of the HEBE, GIPS III and MAST, were pooled. ECGs of 411 STEMI patients were classified as absence (Grade II) or presence (Grade III) of terminal QRS distortion according to Sclarovsky-Birnbaum grading. CMR was performed at approximately 4months and included IS and LVEF. RESULTS: Grade III ischemia was present in 142 of 411 (35%) patients and was more frequently observed with inferior STEMI (P=0.01). In the total cohort and in anterior STEMI, no difference in LVEF or IS was observed between the two Grades. Whereas, in inferior STEMI Grade III was associated with a larger IS (P<0.01) and also, a trend towards a lower LVEF was observed (P=0.09). CONCLUSION: In inferior STEMI, terminal QRS distortion on the initial ECG is associated with a larger IS at approximately 4months, and can be used to identify a high-risk population in the acute phase. Also, a Grade III was associated with a trend towards a lower LVEF.

Correlating both Aldrich and Hellemond score with cardiac magnetic resonance imaging endocardial surface area calculations in the estimation of the area at risk. Electrocardiography scores and endocardial surface area calculations: do they correlate?

INTRODUCTION: Having a bedside tool such as the ECG to assess the myocardial area at risk in a patient presenting with an ST-elevation myocardial infarction would be of great value to the clinician because this could give an insight in the efficiency of intervention therapy and the left ventricular rest function. MATERIALS AND METHODS: From the MAST database (n=106), we included 84 patients, all meeting the STEMI criteria, with a first anterior and/or inferior STEMI. From the admission ECG the Aldrich and Selvester scores were measured and the combined Hellemond score was calculated and correlated with the Cardiac Magnetic Resonance (CMR) estimated endocardial surface area (ESA) using the Spearman coefficient. RESULTS: The correlation between the Aldrich score was r=0.55 (p-value<0.0001) and Hellemond score r=0.45 (p-value<0.0001) with ESA. After exclusion of lateral involvement the correlation increased to 0.62 (p-value<0.0001) for the Aldrich and to 0.49 (p-value<0.0001) for the Hellemond score. CONCLUSION: The additional ECG estimation of infarcted myocardium does not improve the ECG estimation of ischemic myocardium to CMR-based ESA estimation of the myocardial area at risk. The Aldrich score could be improved for STEMIs with lateral involvement.

Bioresorbable scaffolds: talking about a new interventional revolution [corrected].

After the introduction of coronary balloon angioplasty, bare-metal, and drug-eluting stents, fully bioresorbable scaffolds (BRS) could be the fourth revolution in interventional cardiology. The BRS technology shares the advantages of metallic stents regarding acute gain and prevention of acute vessel occlusion by providing transient scaffolding, while potentially overcoming many of the safety concerns of drug-eluting stents. Furthermore, without a permanent metallic cage, the vessel could remodel favourably and atherosclerotic plaques could regress in the long-term. This attracted increased interest and several BRS have been developed. In this review we will describe all BRS which are thus far clinically evaluated and provide an overview of ongoing clinical studies. Although the technology seems to be very promising, more studies including patients with more complex lesions are needed to evaluate whether the BRS can be used in daily clinical practice and if it is indeed becoming a new interventional revolution.

Mycobacterium avium infection and immune restoration disease after highly active antiretroviral therapy in a patient with HIV and normal CD4+ counts.

A patient infected with HIV who had normal CD4+ T-cell counts developed Mycobacterium avium complex lymphadenitis associated with restoration of delayed-type hypersensitivity responses to mycobacterial antigens after commencing highly active antiretroviral therapy (Mycobacterium avium immune restoration disease). This case provides further evidence that delayed-type hypersensitivity responses and CD4+ T-cell counts are independent indicators of the cellular immune defects induced by HIV infection and that Mycobacterium avium immune restoration disease may occur in patients with persistently normal CD4+ T-cell counts.

The effects of metapopulation structure on indirect interactions in host-parasitoid assemblages.

The interaction between two species that do not compete for resources but share a common natural enemy is known as apparent competition. In the absence of other limiting factors, such three-species interactions are impermanent, with one species being excluded from the assemblage by the natural enemy. Here, the effects of metapopulation structure are explored in a system of two hosts that experience apparent competition through a shared parasitoid. A coupled-map lattice model is developed and used to explore species coexistence and patterns of patch occupancy at the metapopulation scale. Linking local and regional dynamics favours coexistence by uncoupling the dynamics of the three species in space. Coexistence is promoted by the inferior species being either a fugitive or a sedentary species. The occurrence of these two mutually exclusive mechanisms of coexistence is influenced by the relative dispersal of the inferior apparent competitor.

Prediction of community integration and vocational outcome 2-5 years after traumatic brain injury rehabilitation in Australia.

OBJECTIVES: To predict community integration and vocational outcomes 2-5 years after traumatic brain injury (TBI). DESIGN: Multivariate correlational design incorporating retrospective data collection and questionnaire follow-up. METHODS: Four hundred and forty six patients admitted to a Head Injury Unit between 1991 and 1995 were contacted. Data on predictor variables (demographic, injury severity and functional) were retrieved from hospital records. Community integration and vocational outcome was assessed by self-administered questionnaire. Two hundred and nine patients/carers completed and returned the questionnaires. Mean follow-up was 3.5 years. Data were analysed by descriptive statistics, multiple regression and discriminant analysis using SPSS. RESULTS: Community integration was predicted by age, disability level and cognition. Length of PTA, cognition, disability levels, GCS, functional status, length of acute stay and prior occupation discriminated those who returned to work. A total of 46.5% returned to work with 74.5% in the same or similar jobs. CONCLUSION: Long term outcomes post-TBI can be predicted by demographic, injury severity and functional status variables.

Top-down versus bottom-up and the Ruritanian bean bug.

In a recent article, Hunter uses the late George Varley and George Gradwell's long-term data on the winter moth (Operophtera brumata) and green tortrix (Tortrix viridana) populations to propose a method of quantifying the relative importance of top-down effects (because of natural enemies) and bottom-up effects (because of resource competition) in influencing population dynamics. We believe this approach is deeply flawed. Using Varley and Gradwell's winter moth study, we show that the problems with Hunter's analysis lie in his misinterpretation of the population dynamics and his inappropriate use of statistical techniques. We also emphasize the importance of distinguishing clearly between two quite different things: firstly, top-down and bottom-up regulation of populations and secondly, the much simpler task of categorizing factors affecting changes in population density as either top-down or bottom-up processes.

Population dynamics of apparent competition in a host-parasitoid assemblage.

The population dynamics of two moth species, Plodia interpunctella (Hübner) and Ephestia kuehniella Zeller in the presence of their shared parasitoid, Venturia canescens (Gravenhorst), were studied in well replicated time series experiments. Moths were prevented from competing for resources and could therefore only interact via the shared parasitoid. This study examines the consequences of apparent competition on the population dynamics of a simple laboratory insect assemblage. Ephestia kuehniella suffers severly in the presence of the shared parasitoid. In all eight replicates, this moth species is eliminated. Time series analysis reveals that the E. kuehniella populations show divergent oscillations. Plodia interpunctella and V. canescens populations show persistent populations. Time series analysis reveals that there is a delayed density dependence acting on these populations and the dynamics are either stable equilibrium or damped oscillations. Repeated-measures analysis of the strength of the indirect interaction reveals that the effects of apparent competition before E. kuehniella is lost are amensal. The indirect interaction between E. kuehniella and P. interpunctella is [-, 0] rather than [-, -].

The effects of a pool of dispersers on host-parasitoid systems.

When individuals migrate in a multi-patch environment, a considerable proportion of their lifetime might be spent in transit between patches. We investigate the effects such a pool of dispersers can have on local stability and dynamics for a variety of multi-patch host-parasitoid models. When an arbitrary number of patches with internal Lotka-Volterra dynamics is coupled via a global pool of dispersers, the equilibrium is globally stable. The global pool is stabilising if dispersal is by hosts only, by parasitoids only, or by both hosts and parasitoids. If dispersal is local such that individuals first enter a pool close to the patch where they originate and then disperse to adjacent pools, the equilibrium is locally stable. We also analyse the situation where the functional response of parasitoids within a patch is Holling type II which is known to destabilise host-parasitoid systems. Coupling this single patch to a pool of dispersers can produce a locally stable interaction, provided the handling time of hosts is not too long. However, the pool provides a biologically realistic example of an interaction that is locally stable but not permanent. The longer the handling time, the smaller the region of population densities within which populations converge to the equilibrium state. In a multi-patch environment with a global disperser pool, the dynamics of the system are not qualitatively different from the single patch case (i.e. the equilibrium can be locally stable but the system is not permanent). In a multi-patch environment with local disperser pools, true spatial interactions between patches can develop. In contrast to the global pool, local pools can destabilise the stable equilibrium of the single patch case. Limit cycles develop around this unstable equilibrium that lead to extremely complicated dynamics. In contrast to the global pool, a system of local pools can exhibit bounded fluctuations so that populations do not go extinct.

Persistence of multispecies host-parasitoid interactions in spatially distributed models with local dispersal.

Recent theoretical studies have shown that dispersal between neighbouring local populations can promote the persistence of interacting metapopulations, even when the local dynamics are unstable and the environment is uniform. This persistence is associated with striking and self-organized spatial patterns in the densities of the local populations. Here we extend previous work on spatially distributed host-parasitoid interactions to wider questions of community structure, by considering various three-species systems: two parasitoid species attacking a common host species; two host species attacked by a single parasitoid species; or a host-parasitoid-hyperparasitoid interaction. In each of these cases, multispecies coexistence of the total populations can occur, even though the local population dynamics are unstable. Furthermore, co-existence tends to be accompanied by some degree of persistent spatial segregation of the competing species, despite the completely uniform environment. At its most extreme, this results in one species being confined to small, relatively static, "islands" within the habitat, giving the appearance of isolated pockets of favourable habitat. That dynamics can impose and maintain such "self-organizing" spatial segregation of competing species, has interesting implications for understanding the local abundance of natural populations.

Metapopulations and equilibrium stability: the effects of spatial structure.

Recently, there has been a great deal of interest in the dynamics of metapopulations, where a number of local populations are coupled via dispersal. The importance of movement for the persistence of an ensemble of locally unstable patches has been established in many studies. In this paper, we present analytical and simulation results concerning the effects of spatial structure on the equilibrium stability of individual populations. We conclude that for general single-species and two-species competition models, the introduction of the spatial dimension in a biologically sensible way has no effect on the overall stability properties. In host-parasitoid models, however, strong host or parasitoid over-dispersal may be destabilizing.

Relative movement patterns of a tephritid fly and its parasitoid wasps.

The extent of within-patch dispersal by a tephritid fly and its four major parasitoids was examined over three field seasons. Hosts and parasitoids were marked using acrylic paint and observed as they oviposited into the flowerheads of marsh thistle, Cirsium palustre. The average recapture rate pooled across all species was 22%. The four parasitoids showed consistently greater rates of movement than the host in all three years. In nearly all comparisons, male dispersal was less than female dispersal. There was no evidence that parasitoids moved longer distances after visiting low quality rather than high quality patches. In the one season it was studied, no correlations between movement and insect size were observed. The relevance of these observations to host-parasitoid population dynamics is discussed.

Host-parasitoid associations in patchy environments.

Studies of insect host-parasitoid interactions have contributed much to the consensus that spatial patchiness is important in the regulation of natural populations. A variety of theoretical models predict that host and parasitoid populations, although unstable in the absence of environmental heterogeneity, may persist at roughly steady overall densities in a patchy environment owing to variation in levels of parasitism from patch to patch. Observed patterns of parasitism, however, have a variety of forms (with variation in attack rates among patches depending directly or indirectly on host density, or showing variation uncorrelated with host density). There is some confusion about the dynamical consequences of these different forms. Here we first show how the dynamical effects of all these forms of environmental heterogeneity can be assessed by a common criterion. This 'CV2 greater than 1 rule' states that the overall population densities will remain roughly steady from generation to generation if the coefficient of variation squared (CV2) of the density of searching parasitoids in the vicinity of each host exceeds approximately unity. By partitioning CV2 into components, we show that both direct and inverse patterns of dependence on host density, and density-independent patterns, all contribute to population regulation in the same way. Second, we show how a maximum-likelihood method can be applied to the kind of field data that are usually available (that is, percentage parasitism versus local host density) to estimate the components of CV2. This analysis indicates that heterogeneity is large enough to stabilize dynamics in 9 of 34 published studies, and that density-independent heterogeneity is the main factor in most cases.

Generalist predators and the importance of spatial density dependence.

CONCLUSION: The model examples in this paper illustrate that non-random spatial distributions of predation or parasitism by polyphagous natural enemies will not necessarily promote population persistence. The test of whether such responses are stabilizing requires the spatial distribution of predation to be examined over a range of total prey densities. As shown in Fig. 2, a contribution to stability will occur if average predation from each spatial response tends to be positively related to total prey density.