Short-term outcome after transcatheter aortic valve replacement with a novel balloon-expandable valve

OBJECTIVES

Transcatheter aortic valve replacement (TAVR) has been expanding rapidly with numerous transcatheter heart valve (THV) systems currently available. The Myval balloon-expandable (BE) valve (Meril Life Sciences Pvt. Ltd., India) is a novel THV system indicated for the treatment of patients with severe aortic stenosis. The primary objective of this study is to assess the safety and performance of the Myval BE valve.

METHODS

In this prospective single-centre study, 120 consecutive patients who underwent TAVR with the Myval BE valve were included. Clinical outcomes were evaluated at 30 days and 6 months using Valve Academic Research Consortium‑2 criteria. All-cause mortality, stroke, acute kidney injury, major vascular complications, moderate or severe paravalvular leakage (PVL) and need for a permanent pacemaker implantation (PPI) were investigated.

RESULTS

At 6‑month follow-up, all-cause death and cardiac death were seen in 5.8% and 0.8% of the patients respectively. Periprocedural stroke and need for PPI were both seen in 3.3% of the patients. Access-site-related vascular and bleeding complications were absent. Improved valve haemodynamics and no moderate to severe PVL could be seen at 30 days. An intermediate valve size was selected in 51% of the patients.

CONCLUSIONS

The Myval BE valve demonstrates improved valve haemodynamics, absence of moderate to severe PVL and good safety outcomes at 6‑month follow-up with low cardiac death rate and acceptable rates of permanent pacemaker implantation and periprocedural stroke. Future randomised controlled trials will further establish the clinical utility of the Myval BE valve.

Bio-distribution and longevity of mesenchymal stromal cell derived membrane particles

Vesicle-based medicines hold great promise for therapy development but essential knowledge on the bio-distribution and longevity of vesicles after administration is lacking. We generated vesicles from the membranes of human mesenchymal stromal cells (MSC) and we demonstrated earlier that these so-called membrane particles (MP) mediate immunomodulatory and regenerative responses in target cells. In the present study we examined the bio-distribution and longevity of MP after intravenous administration in mice. While most vesicle tracking methods are based on imaging techniques, which require labeling of vesicles and can only detect dense accumulations of vesicles, we used proteomics analysis to detect the presence of MP-derived proteins in multiple organs and tissues. MP proteins were mainly present in plasma and leukocytes at 1 h after injection, indicating that MP - in contrast to whole MSC - do not accumulate in the lungs upon first passage but remain in circulation. After 24 h, MP proteins were still present in plasma but were most abundant in the liver. RNA sequencing of livers demonstrated that MP impact liver function and in particular induce metabolic pathways. These data provide a clear view of the bio-distribution and longevity of MP, which is likely extrapolatable to other types of vesicles, and demonstrate that MP circulate for up to 24 h and may be a tool for targeting the liver.

A Case Of Disseminated Histoplasmosis In A Patient With Sarcoidosis

Introduction/Objective

Sarcoidosis is a syndrome of unknown cause that may manifest with clinical, radiographic and pathological findings similar to those seen with histoplasmosis. We present a case of disseminated histoplasmosis in an immunocompetent patient previously diagnosed with sarcoidosis.

Methods/Case Report

A 69-year-old obese male with a history of hypertension, diabetes mellitus and long-standing sarcoidosis was admitted to the hospital for several months of intermittent fevers and pancytopenia. His sarcoidosis was diagnosed 21 years prior, initially involving the lungs and eventually showing cardiac involvement, requiring a pacemaker. He had been treated with methotrexate and prednisone. His recent medical history was also significant for COVID-19 infection, diagnosed 3 months before admission. His fevers were initially attributed to sarcoidosis and his pancytopenia to methotrexate. However, his symptoms continued despite discontinuation of his medications, and further workup was initiated.

Computed tomography showed hepatomegaly, splenomegaly, and lymphadenopathy, concerning for a lymphoproliferative disorder. The patient underwent a bone marrow biopsy that showed noncaseating granulomas and microorganisms consistent with histoplasmosis on fungal stain. Bone marrow cultures were not possible as the marrow was inaspirable. The patient subsequently underwent a lymph node biopsy with both morphology and culture identifying histoplasmosis. Urine and serum histoplasma antigen also returned positive. The patient’s overall clinical picture was consistent with disseminated histoplasmosis and he was administered intravenous Amphotericin B for 3 weeks followed by oral itraconazole for 1 year. One month follow-up after discharge showed significant improvement in the patient’s condition.

Results (if a Case Study enter NA)

N/A

Conclusion

Sarcoidosis reduces T-cell activity, and treatment with steroids causes further immunosuppression and vulnerability for development of a disseminated infection. COVID-19 also presumably increases the predisposition to acquire bacterial or fungal co-infections. Clinicians and pathologists should be aware of the overlap in clinical, radiologic and pathological presentations of sarcoidosis and histoplasmosis to make the correct diagnosis and administer the appropriate treatment.

Update and, internal and temporal-validation of the FRANCE-2 and ACC-TAVI early-mortality prediction models for Transcatheter Aortic Valve Implantation (TAVI) using data from the Netherlands heart registration (NHR)

Background

The predictive performance of the models FRANCE-2 and ACC-TAVI for early-mortality after Transcatheter Aortic Valve Implantation (TAVI) can decline over time and can be enhanced by updating them on new populations. We aim to update and internally and temporally validate these models using a recent TAVI-cohort from the Netherlands Heart Registration (NHR).

Methods

We used data of TAVI-patients treated in 2013-2017. For each original-model, the best update-method (model-intercept, model-recalibration, or model-revision) was selected by a closed-testing procedure. We internally validated both updated models with 1000 bootstrap samples. We also updated the models on the 2013-2016 dataset and temporally validated them on the 2017-dataset. Performance measures were the Area-Under ROC-curve (AU-ROC), Brier-score, and calibration graphs.

Results

We included 6177 TAVI-patients, with 4.5% observed early-mortality. The selected update-method for FRANCE-2 was model-intercept-update. Internal validation showed an AU-ROC of 0.63 (95%CI 0.62-0.66) and Brier-score of 0.04 (0.04-0.05). Calibration graphs show that it overestimates early-mortality. In temporal-validation, the AU-ROC was 0.61 (0.53-0.67).The selected update-method for ACC-TAVI was model-revision. In internal-validation, the AU-ROC was 0.63 (0.63-0.66) and Brier-score was 0.04 (0.04-0.05). The updated ACC-TAVI calibrates well up to a probability of 20%, and subsequently underestimates early-mortality. In temporal-validation the AU-ROC was 0.65 (0.58-0.72).

Conclusion

Internal-validation of the updated models FRANCE-2 and ACC-TAVI with data from the NHR demonstrated improved performance, which was better than in external-validation studies and comparable to the original studies. In temporal-validation, ACC-TAVI outperformed FRANCE-2 because it suffered less from changes over time.

CMR markers for early right ventricular dysfunction in precapillary pulmonary hypertension

Introduction

Precapillary pulmonary hypertension (pPH) causes right ventricular (RV) pressure overload inducing RV remodeling, often resulting in dysfunction and dilatation, heart failure, and ultimately death. The ability of the right ventricle to adequately adapt to increased pressure loading is key for patients' prognosis. RV ejection fraction (RVEF) by cardiac magnetic resonance (CMR) is related to outcome in pPH patients, but this global measurement is not ideal for detecting early changes in RV function. Strain analysis on CMR using feature tracking (FT) software provides a more detailed assessment, and might therefore detect early changes in RV function.

Aim

1) To compare RV strain parameters in pPH patients and healthy controls, and 2) to compare strain parameters in a subgroup of pPH patients with preserved RVEF (pRVEF) and healthy controls.

Methods

In this prospective study, a CMR was performed in pPH patients and healthy controls. Using FT-software on standard cine images, the following RV strain parameters were analyzed: global, septal, and free wall longitudinal strain (GLS, sept-LS, free wall-LS), time to peak strain (TTP, as a % of the whole cardiac cycle), the fractional area change (FAC), global circumferential strain (GCS), global longitudinal and global circumferential strain rate (GLSR and GCSR, respectively). A pRVEF is defined as a RVEF >50%. To compare RV strain parameters in pPH patients to healthy controls, the Mann-Whitney U test was used.

Results

33 pPH-patients (55 [45–63] yrs; 10 (30%) male) and 22 healthy controls (40 [36–48] yrs; 15 (68%) male) were included. All RV strain parameters were significantly reduced in pPH patients compared to healthy controls (see table), except for GCS and GCSR. Most importantly, in pPH patients with pRVEF (n=8) GLS (−26.6% [−22.6 to −27.3] vs. −28.1% [−26.2 to −30.6], p=0.04), sept-LS (−21.2% [−19.8 to −23.2] vs. −26.0% [−24.0 to −27.9], p=0.005), and FAC (39% [35–44] vs. 44% [42–47], p=0.02) were still significantly impaired compared to healthy controls. The RV TTP was significantly increased in pPH patients compared to healthy controls (47% [44–57] vs. 40% [33–43], p≤0.001).

Conclusions

Several CMR-FT strain parameters of the right ventricle are impaired in pPH patients when compared to healthy controls. Moreover, even in pPH patients with a preserved RVEF multiple RV strain parameters (GLS, sept-LS, and FAC) remained significantly impaired, and TTP significantly prolonged, in comparison to healthy controls. This suggests that RV strain parameters may be used as an early marker of RV dysfunction in pPH patients.

Funding Acknowledgement

Type of funding source: None

The rationale of using cerebral embolic protection devices during transcatheter aortic valve implantation

Aortic valve stenosis is one of the most common valvular abnormalities, which can manifest as angina, syncope, dyspnoea and sudden cardiac death. Transcatheter aortic valve implantation (TAVI) has been introduced as an alternative to surgical valve replacement in patients with severe aortic valve stenosis, resulting in less morbidity, shorter time to recovery and similar mortality rates. Progress in this field has reduced complication rates. However, the incidence of peri-procedural stroke remains relatively high (around 4%). To fully utilise the potential of TAVI, cerebral embolic protection devices (CEPD) have been developed and introduced. In this position paper, we aim to summarise the available data on several CEPD.

Analysis of the Prevalence and Causes of Ultrafiltration Failure during Long-Term Peritoneal Dialysis: A Cross-Sectional Study

Background

Ultrafiltration failure (UFF) is a major complication of peritoneal dialysis (PD). It can occur at any stage of PD, but develops in time and is, therefore, especially important in long-term treatment. To investigate its prevalence and to identify possible causes, we performed a multicenter study in The Netherlands, where patients treated with PD for more than 4 years were studied using a peritoneal function test (standard peritoneal permeability analysis) with 3.86% glucose. UFF was defined as net UF < 400 mL after a 4-hour dwell.

Results

55 patients unselected for the presence or absence of UFF were analyzed. Mean age was 48 years (range 18 – 74 years); duration of PD ranged from 48 to 144 months (median 61 months); UFF was present in 20 patients (36%). Patients with and without UFF did not differ in age or duration of PD. Median values for patients with normal UF compared to patients with UFF were, for net UF 659 mL versus 120 mL ( p < 0.01), transcapillary UF rate 3.8 versus 2.1 mL/minute ( p < 0.01), effective lymphatic absorption 1.0 versus 1.6 mL/min ( p < 0.05), mass transfer area coefficient (MTAC) for creatinine 9.0 versus 12.9 mL/min ( p < 0.01), dialysate-to-plasma ratio (D/P) for creatinine 0.71 versus 0.86 ( p < 0.01), glucose absorption 60% versus 73% ( p < 0.01), maximum dip in D/P sodium (as a measure of free water transport) 0.109 versus 0.032 ( p < 0.01), and osmotic conductance to glucose 3.0 versus 2.1 μL/min/mmHg ( p < 0.05). As causes for UFF, high MTAC creatinine, defined as > 12.5 mL/min, or a glucose absorption > 72%, both reflecting a large vascular surface, a lymphatic absorption rate (LAR) of > 2.14 mL/min, and a decreased dip in D/P sodium of < 0.046 were identified. Most patients had a combination of causes (12 patients), whereas there was only a decreased dip in D/P sodium in 3 patients, only high MTAC creatinine in 1 patient, and only high LAR in 2 patients. We could not identify a cause in 2 patients. Both groups had similar clearances of serum proteins and peritoneal restriction coefficients. However, dialysate cancer antigen 125 concentrations, reflecting mesothelial cell mass, were lower in the UFF patients (2.79 vs 5.38 U/L).

Conclusion

The prevalence of UFF is high in long-term PD. It is caused mainly by a large vascular surface area and by impaired channel-mediated water transport. In addition, these patients also had signs of a reduced mesothelial cell mass, indicating damage of the peritoneum on both vascular and mesothelial sites.

Nurses as a source of system-level resilience: Secondary analysis of qualitative data from a study of intravenous infusion safety in English hospitals

Background

Deviations from local policy and national recommended best practice are common in the administration of intravenous infusions, but not all result in negative consequences. Some are the result of nurses’ clinical judgement. However, little is known about such practices and their effects on the safety of intravenous infusions. Our objective was to explore ways in which nurses contribute to system-level resilience when administering intravenous infusions.

Methods

We conducted a secondary analysis of qualitative data from debriefs and focus groups from a mixed methods study of errors and policy deviations in intravenous infusion administration across 16 English hospitals. Analysis focused on nurses’ contributions to system-level resilience, drawing on Larcos’s et al. framework of types of resilience.

Results

Five types of system-level resilience were identified in nurses’ behaviour: anticipatory resilience, responsive resilience, resilience based on past experience, workarounds and nurses performing informal ‘risk assessments’ in relation to how best to treat individual patients. Examples of practices contributing to infusion safety were found for each of these types of resilience.

Conclusion

Our findings suggest nurses are a key source of system-level resilience. Some behaviours that may be considered deviations from policy or best practice are the result of reasoned clinical judgement to improve infusion safety in response to the specific situation at hand. Adaptive behaviour is necessary to cope with the complexity of practice. There is a tension between standardisation and supporting flexibility in safety management.

Spontaneous Platelet Aggregation in Cerebrovascular Disease

50 patients from a group of 130 patients with transient ischaemic attacks or cerebral infarction were found to demonstrate in vitro spontaneous platelet aggregation (SPA) while 80 normal subjects tested never showed this phenomenon.

The following additional findings point towards a possible platelet abnormality:

1. Platelets from 10 patients with SPA when isolated and resuspended in normal plasma still demonstrated SPA while isolated normal platelets resuspended in patient’s plasma did not.

2. Platelets demonstrating SPA showed an increased aggregation tendency upon incubation with ADP while normal platelets developed the expected refractory state.

SPA was found to be dependant upon the presence of divalent cations and could further be inhibited by phentolamine and adenosine. Aspirin effectively abolished SPA in 50 patients and relieved the clinical symptoms of patients with recurrent complaints of transient blindness and paraesthesia.

Spontaneous Platelet Aggregation in Cerebrovascular Disease II

A group of 186 patients with Transient Ischaemic Attacks (TIA) or cerebral Infarction (Cl) was found to demonstrate in vitro Spontaneous Platelet Aggregation (SPA) in 39% of those studied. Of the 176 normal subjects studied the incidence of in vitro SPA was found to be 5%. Further investigation of the phenomenon of SPA revealed that:

1. it is associated with ADP-hyperaggregability, i. e. the threshold concentration to induce second wave aggregation is decreased;

2. it is dependant on the increase in pH which occurs in platelet-rich plasma stirring in an aggregometer while concurrent ADP-hyperaggregability is independant of this change in pH;

3. it is associated with malondialdehyde production and the release of endogenous 5- hydroxytryptamine; and that

4. in addition Km and Vmax values for [14C]-5HT incorporation are normal; and that

5. no gross abnormalities of the platelet membrane glycoproteins were apparent although occasionally glycoprotein III was found to be increased.

This study demonstrates abnormal platelet behaviour in patients with TIA and Cl where the enzyme system involved in thromboxane production is sufficiently stimulated, by stirring alone, to induce aggregation of platelets and the release reaction.

Acetylsalicylic acid abolishes SPA and prolongs the bleeding time with similar characteristics as has been described for normal individuals. Plasma (3-thromboglobulin levels are significantly increased in the patients studied. However, no correlation was established with the incidence of in vitro SPA.

Orientation-dependent stereo Wigner time delay and electron localization in a small molecule

Attosecond metrology of atoms has accessed the time scale of the most fundamental processes in quantum mechanics. Transferring the time-resolved photoelectric effect from atoms to molecules considerably increases experimental and theoretical challenges. Here we show that orientation- and energy-resolved measurements characterize the molecular stereo Wigner time delay. This observable provides direct information on the localization of the excited electron wave packet within the molecular potential. Furthermore, we demonstrate that photoelectrons resulting from the dissociative ionization process of the CO molecule are preferentially emitted from the carbon end for dissociative ²Σ states and from the center and oxygen end for the ²Π states of the molecular ion. Supported by comprehensive theoretical calculations, this work constitutes a complete spatially and temporally resolved reconstruction of the molecular photoelectric effect.

Defining and Measuring a Standard Set of Patient-Relevant Outcomes in Coronary Artery Disease

Systematic outcome measurement enables to continuously improve treatment results and stimulates dissemination of best practices. For patients with coronary artery disease, no examples yet exist of standard sets of patient-relevant outcome measures that have already been fully implemented at a large scale in clinical care. The aim of this paper is twofold: (1) to share the standard set of outcome measures as developed by Meetbaar Beter, and (2) to show how the standard set is presented and published to support improvement of cardiac care. A step-wise approach was followed by an expert panel to construct a standard set of outcome measures. This resulted in a comprehensive set of relevant outcome measures, comprising 4 generic and 11 treatment-specific outcomes. Both short-term and long-term outcomes measures up to 5 years of follow-up were included. Relevant initial conditions were selected to enable case-mix adjustment. The standard set has been implemented in 21 hospitals across the Netherlands. The results and experiences have been used to fine-tune the set in 4 reporting cycles in 2012 to 2016, using an annual maintenance cycle. Currently about 83,000 percutaneous coronary interventions and 30,000 coronary artery bypass graftings are included in the dataset, covering the majority of all percutaneous coronary interventions and coronary artery bypass graftings in the Netherlands. In conclusion, Meetbaar Beter has defined and implemented a comprehensive set of patient-relevant outcome measures for coronary artery disease, and the variation of the results among the centers indicates that there are sufficient opportunities to further improve cardiac care in the Netherlands.

Comparison of attosecond streaking and RABBITT

Recent progress in the generation of ultra-short laser pulses has enabled the measurement of photoionization time delays with attosecond precision. For single photoemission time delays the most common techniques are based on attosecond streaking and the reconstruction of attosecond beating by interference of two-photon transitions (RABBITT). These are pump-probe techniques employing an extreme-ultraviolet (XUV) single attosecond pump pulse for streaking or an attosecond pump pulse train for RABBITT, and a phase-locked infrared (IR) probe pulse. These techniques can only extract relative timing information between electrons originating from different initial states within the same atom or different atoms. Here we address the question whether the two techniques give identical timing information. We present a complete study, supported by both experiments and simulations, comparing these two techniques for the measurement of the photoemission time delay difference between valence electrons emitted from the Ne 2p and Ar 3p ground states. We highlight not only the differences and similarities between the two techniques, but also critically investigate the reliability of the methods used to extract the timing information.

Prophylactic intraoperative antithrombotics in open infrainguinal arterial bypass surgery: a systematic review

Unfractionated heparin (UFH) is used intraoperatively as antithrombotic by most vascular surgeons worldwide during infrainguinal bypass surgery (IABS) to reduce the risk of peroperative and early graft thrombosis. To reduce the harmful side effects of UFH (bleeding complications, HIT) and to reduce peroperative and early graft failure, other pharmaceuticals have been suggested for IABS. A systematic review was performed using MEDLINE, EMBASE and Cochrane databases. Only 9 studies on IABS and intraoperative antithrombotic use were eligible for review. Between studies heterogeneity was high and investigated study populations were often of small size. No study was retrieved comparing UFH to no-UFH. Dextran, human antithrombin and iloprost showed no beneficial effect compared to UFH alone for patency, mortality and morbidity. Low molecular weight heparin (LMWH) has potential benefits compared to UFH, but a statistically significant effect could not be demonstrated from the current review. The use of UFH during IABS to prevent intraoperative graft thrombosis has not been proven in randomized clinical trials. Dextran, human antithrombin and iloprost showed to be of no added beneficial effect for the patient compared to UFH alone. Data on the use of LMWH instead of UFH are promising, but no statistically significant benefit could be reproduced from literature. Results from a recent Cochrane review were favourable for LMWH, but it appeared that included data were not complete in that review. Randomized controlled trials are required for intra-operative use of antithrombotics and to improve peroperative and early patency after IABS.

Perioperative prophylactic antithrombotic strategies in vascular surgery: current practice in the Netherlands

AIM

The aim of this study was to evaluate the current practice of the use of perioperative antithrombotic drugs to prevent arterial thrombo-embolic complications during arterial vascular surgery by Dutch vascular surgeons. Aim was also to compare the results with the literature and to evaluate the effect of guidelines.

METHODS

A comprehensive questionnaire was sent to all Dutch vascular surgeons performing arterial reconstructive surgery.

RESULTS

The response rate was 84%. Acetylsalicylic acid (ASA) was continued perioperatively by most surgeons (91%). Clopidogrel was discontinued by the majority of respondents (65%). During operation 97% of surgeons administered unfractionated heparin (UFH) before arterial clamping. A minority (11%) measures peroperatively anticoagulant activity in patients' blood. After infrainguinal venous bypass most surgeons (81%) preferred monotherapy with vitamin K antagonists (VKA), in agreement with the Dutch guideline in this respect. Before the introduction of the guideline in 2005, a survey was performed in 2004. Results of our 2011 survey showed more respondents (6% to 11%) prescribed ASA or VKA according to these guidelines.

CONCLUSION

This survey showed a recognizable pattern of variation for perioperative arterial thrombosis prophylaxis amongst Dutch vascular surgeons, in agreement with reports from other countries over the past 20 years. Although a higher percentage of surgeons complied in 2011 with existing guidelines than in 2004, guidelines were not completely met. Possibly because current guidelines are not fully supported by evidence and do not cover all aspects of perioperative arterial thrombosis prophylaxis. Clearly there is need for (more) convincing data based on RCT's concerning the various aspects of perioperative arterial thrombosis prophylaxis.

Leaf photosynthesis and respiration of three bioenergy crops in relation to temperature and leaf nitrogen: how conserved are biochemical model parameters among crop species?

Given the need for parallel increases in food and energy production from crops in the context of global change, crop simulation models and data sets to feed these models with photosynthesis and respiration parameters are increasingly important. This study provides information on photosynthesis and respiration for three energy crops (sunflower, kenaf, and cynara), reviews relevant information for five other crops (wheat, barley, cotton, tobacco, and grape), and assesses how conserved photosynthesis parameters are among crops. Using large data sets and optimization techniques, the C(3) leaf photosynthesis model of Farquhar, von Caemmerer, and Berry (FvCB) and an empirical night respiration model for tested energy crops accounting for effects of temperature and leaf nitrogen were parameterized. Instead of the common approach of using information on net photosynthesis response to CO(2) at the stomatal cavity (A(n)-C(i)), the model was parameterized by analysing the photosynthesis response to incident light intensity (A(n)-I(inc)). Convincing evidence is provided that the maximum Rubisco carboxylation rate or the maximum electron transport rate was very similar whether derived from A(n)-C(i) or from A(n)-I(inc) data sets. Parameters characterizing Rubisco limitation, electron transport limitation, the degree to which light inhibits leaf respiration, night respiration, and the minimum leaf nitrogen required for photosynthesis were then determined. Model predictions were validated against independent sets. Only a few FvCB parameters were conserved among crop species, thus species-specific FvCB model parameters are needed for crop modelling. Therefore, information from readily available but underexplored A(n)-I(inc) data should be re-analysed, thereby expanding the potential of combining classical photosynthetic data and the biochemical model.

Ultrasound-accelerated thrombolysis for lower extremity ischemia: multicenter experience and literature review

AIM

This study evaluates the short-term outcome of ultrasound-accelerated thrombolysis in patients with lower extremity ischemia caused by thromboembolic occlusions.

METHODS

A retrospective cohort study was conducted from December 2008 to May 2011 of 57 patients (42 men; median age, 66 ± 11 years) undergoing 62 episodes of ultrasound-accelerated thrombolysis for thromboembolic arterial occlusions of the lower extremities. The EKOS EndoWave System (EKOS Corporation, Bothell, WA, USA) was combined with urokinase (100000 IU/hour). Thirty-day and 6-month follow-up consisted of clinical evaluation, and Duplex scan or magnetic resonance angiography of the treated extremity.

RESULTS

Initial technical success was 97%, radiologic success was 82%, and overall clinical success was 77%. Median thrombolysis time was 21 hours (IQR, 15-24). In 38 of 51 procedures with successful lysis (75%) complete lysis was achieved within 24 hours. Major hemorrhage occurred in 2 procedures (3%), and distal embolization in 2 procedures (3%). During the initial hospitalization, the major amputation rate was 8% (N.=5) and the mortality rate was 2% (N.=1). The 30-day patency rate was 81%, without additional mortality. During a median 6-month (range, 2-14) follow-up, 9 reinterventions were performed. Two patients underwent major amputation and 3 patients died; because of malignancy (N.=2) and stroke (N.=1).

CONCLUSION

Initial success rates of ultrasound-accelerated thrombolysis are high and complication rate is low. However, reintervention rate during short-term follow-up for recurrent ischemia is substantial. Results from a randomized controlled trial comparing ultrasound-accelerated thrombolysis with standard thrombolysis for lower extremity ischemia (DUET, Current Controlled Trials, ISRCTN72676102) are eagerly awaited.

Simulation of wheat growth and development based on organ-level photosynthesis and assimilate allocation

Intimate relationships exist between form and function of plants, determining many processes governing their growth and development. However, in most crop simulation models that have been created to simulate plant growth and, for example, predict biomass production, plant structure has been neglected. In this study, a detailed simulation model of growth and development of spring wheat (Triticum aestivum) is presented, which integrates degree of tillering and canopy architecture with organ-level light interception, photosynthesis, and dry-matter partitioning. An existing spatially explicit 3D architectural model of wheat development was extended with routines for organ-level microclimate, photosynthesis, assimilate distribution within the plant structure according to organ demands, and organ growth and development. Outgrowth of tiller buds was made dependent on the ratio between assimilate supply and demand of the plants. Organ-level photosynthesis, biomass production, and bud outgrowth were simulated satisfactorily. However, to improve crop simulation results more efforts are needed mechanistically to model other major plant physiological processes such as nitrogen uptake and distribution, tiller death, and leaf senescence. Nevertheless, the work presented here is a significant step forwards towards a mechanistic functional-structural plant model, which integrates plant architecture with key plant processes.

Analysing lodging of the panicle bearing cereal teff (Eragrostis tef)

Lodging, the permanent displacement of crop plants from their vertical because of root or shoot failure, is a major yield constraint of the gluten free, panicle bearing cereal teff. The objective of this paper was to analyse the causes of lodging of teff by using, modifying and validating conventional biomechanical models. The model parameters were obtained from a field trial with two contrasting teff cultivars, using novel in situ and laboratory measurements under wet and dry conditions. Cross-species model validation was done with rice (Oryza sativa). Teff is more susceptible to root lodging than to shoot lodging, although the data indicated that shoot strength is also insufficient. Hence, simultaneously breeding for both improved root anchorage and shoot strength is advocated. The study showed that the lodging model, derived for the spike-bearing cereal wheat, needed modifications in order to be able to deal with panicle-bearing plants such as teff and rice. Water adhering to plants owing to rain or dew increased calculated lodging susceptibility. To prevent underestimation of lodging susceptibility, future lodging research should be done under completely wet conditions (water saturated soil and wetted shoots).

Functional-structural plant modelling: a new versatile tool in crop science

Plants react to their environment and to management interventions by adjusting physiological functions and structure. Functional-structural plant models (FSPM), combine the representation of three-dimensional (3D) plant structure with selected physiological functions. An FSPM consists of an architectural part (plant structure) and a process part (plant functioning). The first deals with (i) the types of organs that are initiated and the way these are connected (topology), (ii) co-ordination in organ expansion dynamics, and (iii) geometrical variables (e.g. leaf angles, leaf curvature). The process part may include any physiological or physical process that affects plant growth and development (e.g. photosynthesis, carbon allocation). This paper addresses the following questions: (i) how are FSPM constructed, and (ii) for what purposes are they useful? Static, architectural models are distinguished from dynamic models. Static models are useful in order to study the significance of plant structure, such as light distribution in the canopy, gas exchange, remote sensing, pesticide spraying studies, and interactions between plants and biotic agents. Dynamic models serve quantitatively to integrate knowledge on plant functions and morphology as modulated by environment. Applications are in the domain of plant sciences, for example the study of plant plasticity as related to changes in the red:far red ratio of light in the canopy. With increasing availability of genetic information, FSPM will play a role in the assessment of the significance towards plant performance of variation in genetic traits across environments. In many crops, growers actively manipulate plant structure. FSPM is a promising tool to explore divergent management strategies.

Child slaves and freemen at the Spiritan Mission in Soyo, 1880-1885

Catholic missionaries in late nineteenth- and early twentieth-century Africa more commonly than Protestants purchased slaves to build their mission stations. This article provides a micro-historical analysis of the redemption of child slaves by the Holy Ghost Fathers in Soyo, West Central Africa, in the years immediately preceding the colonial partition of Africa. It argues that the Spiritan missionaries liberated slaves for instrumental rather than humanitarian reasons. As local freemen were difficult to control, the mission depended for its growth on the import of slave children. Furthermore, since the missionaries operated on the same markets and paid the same prices for slaves as regular buyers, their purchasing practices showed a strong resemblance with ordinary slave trading.

[High mortality in a herd with signs of jejunal hemorrhage syndrome]

Eleven cows from a herd of 80 dairy cows (14%) died over a 7-month period. Death occurred within 12-24 hours of the onset of the first clinical signs, namely, dullness and a decrease (mean 25%) in milk production. Within 12 hours the cows were unable to rise, felt cold, and were restless. Examined mucous membranes were pale. Two of three cows examined at necropsy had blood in the jejunum and high counts of Clostridium perfringens. Jejunal hemorrhage syndrome was diagnosed in these two cows on the basis of the clinical signs and postmortem findings.

[Stillbirth/perinatal weak calf syndrome in dairy heifers: results of a pilot study]

A pilot study of 10 Dutch dairy herds was performed to investigate possible causes of stillbirth/perinatal weak calf syndrome in heifers. Possible causes and advice for further investigations on farms affected by this syndrome are discussed based on the results of investigations of blood and urine from pregnant young stock, postmortem examination of still-born calves, and a questionnaire held among farmers. Infections with Neospora caninum, Salmonella spp. or Leptospira hardjo, or a deficiency of iodine could be excluded.

Sonotherapy, antirestenotic therapeutic ultrasound in coronary arteries: the first clinical experience

We studied the safety and feasibility of intracoronary sonotherapy (IST) and its effect on the coronary vessel at 6 months. Thirty-seven patients with stable or unstable angina were included (40 lesions). The indication was de novo lesion (n = 26), restenosis (n = 2), in-stent restenosis (n = 11), and a total occlusion of a venous bypass graft. After successful angioplasty, IST was performed using a 5 Fr catheter with three serial ultrasound transducers operating at 1 MHz. IST was successfully performed in 36 lesions (success rate, 90%). IST exposure time per lesion was 718 +/- 127 sec. During hospital stay, one patient died due to a bleeding complication. At 6-month follow-up, one patient experienced acute myocardial infarction, eight patients underwent repeat PTCA. No patient underwent CABG. Late lumen loss was 1.05 +/- 0.70 mm with a restenosis rate of 25%. IVUS analysis revealed a neointima burden of 25% +/- 11%. IST can be applied safely and with high acute procedural success. Sonotherapy-related major adverse events were not observed. Late lumen loss and neointimal growth were similar to conventional PTCA approaches. These results justify the initiation of randomized clinical efficacy studies.

Reduced impact of migraine in everyday life: an observational study in the Dutch Society of Headache Patients

OBJECTIVE

To explore the percentage of patients who report a reduced impact of migraine on their life, and to which factors this improvement can be attributed.

METHODS

Four hundred forty-eight members of the Dutch Society of Headache Patients answered a set of structured questionnaires, including the Migraine-Specific Quality of Life instrument (MSQOL).

RESULTS

Of this group, 70% reported a reduced impact of migraine. The most frequently reported reason for this reduction was a change in medication (77%); in particular, change to a triptan. Other favorable factors included a change in life-style (56%): 42% of patients reported more relaxed coping with migraine, a reduction of stress in general (28%) and of stress related to work (24%), and leading a more regular life-style (21%). In addition, social support was frequently mentioned, particularly that offered by the Dutch Society of Headache Patients (58%), family (46%), and their general practitioner (28%). The patients who reported a reduced impact of migraine had less migraine attacks and a higher quality of life than those who did not report such a reduction.

CONCLUSION

The results confirm that factors that are proven effective in clinical trials on migraine also have these effects outside a formal experimental environment.

[Percutaneous transluminal coronary angioplasty in 1980-85 and 1995-96: more frequent multivessel disease, fewer reoperations and no change in mortality 1 and 5 years postoperatively]

OBJECTIVE

To describe the characteristics of patients undergoing coronary angioplasty (PTCA) over the past 20 years and the outcome after 1 and 5 years.

DESIGN

Prospective follow-up study.

METHODS

All patients who underwent a first PTCA in the Thorax centre of the Erasmus Medical Centre in Rotterdam during the period from 1 September 1980 through 30 November 1985 (group I) were compared with all patients who likewise underwent such a first PTCA during the period between 1 September 1995 and 31 December 1996 (group II). Data on the patients, the operations, any reoperations and the mortality were obtained from patient records, general practitioners and municipal archives. Cumulative percentages of survival and of not having rePTCA or coronary artery bypass surgery (CABG) were analysed by using the Kaplan-Meier-method.

RESULTS

Group I consisted of 856 patients and group II of 840 patients. The percentage of males decreased over the years from 80% to 69%. The average age increased from 56 to 60 years; the oldest patient in group I was 75 years and the oldest in group II was 87 years. The percentage of patients with multivessel disease increased from 36% to 44%. Stent implantation occurred in 55% of the patients in group II (0% in group I). The necessity for urgent CABG due to unsuccessful PTCA decreased from 9.4% to 1%. After 1 year, the percentage of coronary revascularisations was 28.8% in group I and 22.6% in group II (p = 0.01). The perioperative mortality and the 5-year survival were not significantly different in the two groups (group I: 1.3% and 90%; group II: 2.4% and 88%, respectively). For both groups, higher age, a smaller ejection fraction, more extensive vascular disease and no treatment with statins were independent predictors of a higher mortality after 5 years. In group II, renal function disorders were the most important predictor of higher mortality.

Non-invasive coronary angiography with multislice spiral computed tomography: impact of heart rate

OBJECTIVE

To evaluate the impact of heart rate on the diagnostic accuracy of coronary angiography by multislice spiral computed tomography (MSCT).

DESIGN

Prospective observational study.

PATIENTS

78 patients who underwent both conventional and MSCT coronary angiography for suspicion of de novo coronary artery disease (n=53) or recurrent coronary artery disease after percutaneous intervention (n=25).

SETTING

Tertiary referral centre.

METHODS

Intravenously contrast enhanced MSCT coronary angiography was done during a single breath hold, and ECG synchronised images were reconstructed retrospectively. All coronary segments of > or = 2.0 mm without stents were evaluated by two investigators and compared with quantitative coronary angiography. Patients were classified according to the average heart rate (mean (SD)) into three equally sized groups: group 1, 55.8 (4.1) beats/min; group 2, 66.6 (2.8) beats/min; group 3, 81.7 (8.8) beats/min.

RESULTS

Image quality was sufficient for analysis in 78% of the coronary segments in patients in group 1, 73% in group 2, and 54% in group 3 (p < 0.01). The sensitivity and specificity for detecting significant stenoses (> or = 50% lumen reduction) in these assessable segments were: 97% (95% confidence interval (CI) 84% to 100%) and 96% in group 1; 74% (52% to 89%) and 94% in group 2; and 67% (33% to 90%) and 94% in group 3 (p < 0.05). Accounting for all segments of > or = 2.0 mm, including lesions in non-assessable segments as false negatives, the sensitivity decreased to 82% (28/34 lesions, 95% CI 69% to 91%), 61% (14/23 lesions, 42% to 77%), and 32% (6/19 lesions, 15% to 50%), respectively (p < 0.01).

CONCLUSIONS

MSCT allows reliable coronary angiography in patients with low heart rates.

Routine intracoronary beta-irradiation. Acute and one year outcome in patients at high risk for recurrence of stenosis

AIMS

Intracoronary radiation is a promising therapy potentially reducing restenosis following catheter-based interventions. Currently, only limited data on this treatment are available. The feasibility and outcome in daily routine practice, however, is unknown.

METHODS AND RESULTS

In 100 consecutive patients, intracoronary beta-radiation was performed with a (90)Strontium system (Novoste Beta-Cathtrade mark) following angioplasty. Predominantly complex (73% type B2 and C) and long lesions (length 24.3+/-15.3 mm) were included (37% de novo, 19% restenotic and 44% in-stent restenotic lesions). Radiation success was 100%. Mean prescribed dose was 19.8+/-2.5 Gy. A pullback procedure was performed in 19% lesions. Geographic miss occurred in 8% lesions. Periprocedural thrombus formation occurred in four lesions, dissection in nine lesions. During hospital stay, no death, acute myocardial infarction, or repeat revascularization was observed. Major adverse cardiac events occurred predominantly between 6 and 12 months after the index procedure with major adverse cardiac event-free survival of 66% at 12 months (one death, 10 Q-wave myocardial infarctions, 23 target vessel revascularizations; ranked for worst event).

CONCLUSION

Routine catheter-based intracoronary beta-radiation therapy after angioplasty is safe and feasible with a high acute procedural success. The clinical 1-year follow-up showed delayed occurrence of major adverse cardiac events between 6 and 12 months after the index procedure.

The environmental pollutant hexachlorobenzene causes eosinophilic and granulomatous inflammation and in vitro airways hyperreactivity in the Brown Norway rat

Based on observations that the persistent environmental pollutant hexachlorobenzene (HCB) induces inflammatory skin lesions and eosinophilic and granulomatous lung pathology as well as in vivo airways hyperresponsiveness to methacholine in the BN/SsNOlaHsd rat (Michielsen et al., Toxicol Appl Pharmacol 172:11-20, 2001), which are features of human Churg-Strauss syndrome (CSS), we have investigated whether HCB induced other features of CSS such as asthma and systemic vasculitis involving the heart and kidneys in this strain of rat. To this end, BN/SsNOlaHsd rats received control feed or feed supplemented with 450 mg/kg HCB. On days 6, 14 or 21, tracheas were isolated to assess non-specific in vitro airways hyperresponsiveness (AHR) to cumulative concentrations of arecoline and serotonin. In addition, lungs were lavaged to count and differentiate lavage cells, and skin, lungs, heart, kidneys, and lymph nodes were processed for histopathological investigation. HCB induced eosinophilic and granulomatous lung pathology in the BN/SsNOlaHsd rat, which became more severe with time and was associated with significant in vitro AHR to arecoline. Moreover, as in CSS-patients, systemic effects on spleen and lymph nodes were observed in HCB-fed BN/SsNOlaHsd rats, as well as development of skin lesions with vascular changes and eosinophilic infiltrates. In contrast, cardiac or renal involvement, frequently seen in CSS-patients, was not seen in HCB-fed rats. More importantly, there were no indications of necrotizing vasculitis, a hallmark feature of CSS, in the lungs and skin of BN/SsNOlaHsd rats. Thus, it is concluded that the persistent environmental pollutant HCB possibly induces a mild or early stage of CSS in the BN/SsNOlaHsd rat that may evolve into fully developed CSS after prolonged exposure to HCB.

Coronary restenosis elimination with a sirolimus eluting stent: first European human experience with 6-month angiographic and intravascular ultrasonic follow-up

AIMS

Coronary stenting is limited by a 10%-60% restenosis rate due to neointimal hyperplasia. Sirolimus is a macrocyclic lactone agent that interacts with cell-cycle regulating proteins and inhibits cell division between phases G1 and S1. The hypothesis tested in this study is that local delivery of sirolimus with an eluting stent can prevent restenosis.

METHODS AND RESULTS

Fifteen patients were treated with 18 mm sirolimus eluting BX VELOCITY stents. Quantitative angiography and three-dimensional quantitative intravascular ultrasound were performed at implantation and at the 6 months follow-up. All stent implantations were successful. One patient died on day 2, of cerebral haemorrhage and one patient suffered a subacute stent occlusion due to edge dissection (re-PTCA, CKMB 42). At 9 months no further adverse events had occurred and all patients were angina free. Quantitative coronary angiography revealed no change in minimal lumen diameter and percent diameter stenosis and hence no in-lesion or in-stent restenosis. Quantitative intravascular ultrasound showed that intimal hyperplasia volume and percent obstruction volume at follow-up were negligible at 5.3 mm(3)and 1.8%, respectively. No edge effect was observed in the segments proximal and distal to the stents.

CONCLUSION

Implantation of a sirolimus-eluting stent seems to effectively prevent intimal hyperplasia.

[Twelve year triage and thrombolysis treatment prior to hospitalization for myocardial infarction patients in the Rotterdam area of the Netherlands: outstanding short-term and long-term results]

OBJECTIVE

To describe the results of thrombolysis prior to hospitalisation in patients with evolving myocardial infarction.

DESIGN

Prospective cohort study.

METHOD

The 'Reperfusion for acute infarcts Rotterdam' (Dutch acronym: REPAIR) programme aims to minimise treatment delay in patients with evolving myocardial infarction by the initiation of thrombolytic therapy prior to hospital admission. For patients with symptoms that indicate a developing myocardial infarction, treatment is initiated immediately by the ambulance personnel at the patient's home, once the diagnosis has been confirmed with the help of a portable 12-lead ECG system. The interval between the onset of symptoms and the thrombolysis infusion was recorded for all patients, as well as any complications which occurred during transportation. The long-term survival was determined using data from the municipal registration.

RESULTS

In the period 1988-2000, 1487 patients were treated using the REPAIR protocol, 80% of these within two hours after the onset of symptoms. In 9 cases (0.6%) a thrombolytic treatment had been initiated, whereas the diagnosis 'myocardial infarction' was not confirmed at the hospital. During transport 40 patients (2.7%) experienced ventricle fibrillation, 25 (1.7%) severe hypotension, and 2 patients (0.1%) died. Mortality at 30 days and at one, five, and ten years was 4.9%, 7.3%, 16.2% en 30.1%, respectively. Patients treated within two hours after the onset of symptoms had lower mortality rates than those treated later: at one year 6.7% versus 9.7%, and at 5 years 14.0% versus 25.1% (Kaplan-Meier estimates; log rank test: p = 0.001).

CONCLUSION

Immediate thrombolytic treatment of patients with a developing myocardial infarction which could be safely initiated by ambulance personnel, resulted in excellent short-term and long-term survival.

On the annoyance caused by impulse sounds produced by small, medium-large, and large firearms

A laboratory study was designed in which the annoyance was investigated for 14 different impulse sound types produced by various firearms ranging in caliber from 7.62 to 155 mm. Sixteen subjects rated the annoyance for the simulated conditions of (1) being outdoors, and (2) being indoors with the windows closed. In the latter case, a representative outdoor-to-indoor reduction in sound level was applied. It was anticipated that the presumed additional annoyance caused by the "heaviness" of the impulse sounds might be predicted from the difference between the C-weighted sound exposure level (CSEL; LCE) and the A-weighted sound exposure level (ASEL; LAE). In the outdoor rating conditions, the annoyance was almost entirely determined by ASEL. The explained variance, r2, in the mean ratings by ASEL was 0.95. In the indoor rating conditions, however, the explained variance in the annoyance ratings by (outdoor) ASEL was significantly increased from r2 = 0.87 to r2= 0.97 by adding the product (LCE-LAE)(LAE-alpha) as a second variable. In combination with a 12-dB adjustment for small firearms, the present results showed that for the entire set of impulse sounds rated indoors with windows closed, the rating sound level, Lr, is given by Lr=LAE +12dB+beta(LCE-LAE)(LAE-alpha), with alpha=45dB and beta=0.015dB(-1). For the outdoor rating condition, the optimal parameter values were equal to alpha=57 dB and, again, beta=0.015 dB(-1). In validation studies, in which the effects of the present rating procedure will be compared to field data, it has to be determined to what extent the constants alpha and beta have to be adjusted.

The mercapturic acid biotransformation pathway of hexachlorobenzene is not involved in the induction of splenomegaly, or skin and lung lesions in the Brown Norway rat

Involvement of the mercapturic acid pathway in the induction of splenomegaly and skin and lung pathology by hexachlorobenzene (HCB) in the rat was investigated by seeking to determine whether pentachloronitrobenzene (PCNB) has the same inflammatory effects as HCB, since both compounds are directly conjugated to glutathione, and further processed into the same mercapturic acid metabolites which are excreted via the urine. Female Brown Norway (BN/SsNO1aHsd) rats at 3 to 4 weeks of age were orally exposed to diets with or without supplementation with 450 mg HCB or equimolar (467 mg) or higher (934 mg) amounts of PCNB per kilogram of diet over 4 weeks. Gross skin lesion development and body weight gains were assessed during exposure and spleen and liver weights as well as histopathologic changes in skin and lung were assessed after exposure. After 3 weeks of exposure, urinary metabolites of the mercapturic acid and oxidative biotransformation pathways were identified using high-performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometry (LC-MS). Oral exposure of the rats to 450 mg/kg HCB resulted in an increase in relative spleen and liver weights as well as in the development of skin and lung pathology in the absence of overall liver toxicity. Equimolar or higher concentrations of PCNB caused none of these effects. Urinary levels of the mercapturic acid N-acetyl-S-(pentachlorophenyl)-cysteine (PCP-NAC), were comparable in HCB- and PCNB-treated rats. Levels of closely related methylsulfide derivatives of PCP-NAC, also generated via the same mercapturic acid pathway, appeared to be significantly higher in PCNB- than in HCB-treated rats, whereas the reverse was true for the urinary levels of the oxidative metabolite pentachlorophenol (PCP). Thus, results indicate that metabolites of the mercapturic acid pathway are not involved in the induction of splenomegaly and skin and lung pathology caused by HCB exposure in BN rats and that the main urinary metabolite of HCB in these BN rats is PCP. Since PCP itself, as well as other cytochrome P450-derived metabolites from HCB, are not likely to be involved in the induction of splenomegaly and skin and lung pathology, it is suggested that either the parent compound HCB or as-yet-unidentified non-P450-generated metabolites are involved in these inflammatory effects of HCB.