Cardiology

Genetic Regulation of Angiogenesis and Lymphangiogenesis: Visualization and characterization of the vasculature (Doctoral Thesis)

Bos, F.L. — 2011-10-19T00:00:00Z

Aelius Galenus (AD 129 – 199) was one of the first persons to explore the blood vasculature. During his work as physician and surgeon, he recognized distinct differences in blood vessels. During surgery, he observed that vessels were filled with either dark or bright blood. He believed that the human blood vascular system contained two one-way blood distribution routes. The dark (venous) blood was generated directly from food uptake in the liver, whereas the bright (arterial) blood was generated in the heart. From the heart and liver, blood was then equally distributed and ‘consumed’ by all other organs in the body. To complete the vascular system, blood was then regenerated in either the heart or liver (reviewed in (Carmeliet, 2005). This ‘two-one way circulation’ theory was believed for centuries and it was only until the 16th century that the British biologist and medical doctor William Harvey could show that Galenus was wrong. Harvey characterized and quantified the blood volume which passes the heart and concluded that this was much larger than the amount of blood that could be generated by the body itself (On the Motion of the Heart and Blood in Animals, 1628, William Harvey). Harvey postulated that there had to be a circulatory loop in the body which consisted of the heart and a connected vessel system. With a simple experiment, by tightening a ligature on to the upper arm of an individual, he indeed identified a circulatory loop which was connected to the heart and identified the presence of arteries and veins but also functional differences between arteries and veins (On The Motion Of The Heart And Blood In Animals, 1628, William Harvey, (Carmeliet, 2005).

The role of multi-slice computed tomography in stable angina management: a current perspective (Article)

Weustink, A.C. — 2011-08-01T00:00:00Z

Contrast-enhanced CT coronary angiography (CTCA) has evolved as a reliable alternative imaging modality technique and may be the preferred initial diagnostic test in patients with stable angina with intermediate pre-test probability of CAD. However, because CTCA is moderately predictive for indicating the functional significance of a lesion, the combination of anatomic and functional imaging will become increasingly important. The technology will continue to improve with better spatial and temporal resolution at low radiation exposure, and CTCA may eventually replace invasive coronary angiography. The establishment of the precise role of CTCA in the diagnosis and management of patients with stable angina requires high-quality randomised study designs with clinical outcomes as a primary outcome.

Final results of the HEALING IIB trial to evaluate a bio-engineered CD34 antibody coated stent (Genous™Stent) designed to promote vascular healing by capture of circulating endothelial progenitor cells in CAD patients (Article)

Dekker, W.K. den — 2011-07-18T00:00:00Z

Objective: To assess the safety and efficacy of the Genous™ endothelial progenitor cell (EPC) capturing stent in conjunction with HmG-CoA-reductase inhibitors (statins) to stimulate EPC recruitment, in the treatment of patients with de novo coronary artery lesions. Methods and results: The HEALING IIB study was a multi-center, prospective trial, including 100 patients. The primary efficacy endpoint was late luminal loss by QCA at 6-month follow-up (FU). Although statin therapy increased relative EPC levels by 5.6-fold, the angiographic outcome at 6 month FU was not improved in patients with an overall in-stent late luminal loss of 0.76 ± 0.50 mm. The composite major adverse cardiac events (MACE) rate was 9.4%, whereas 6.3% clinically justified target lesion revascularizations (TLRs) were observed. 2 Patients died within the first 30 days after stent implantation due to angiographically verified in-stent thrombosis. At 12 month FU, MACE and TLR increased to 15.6% and 11.5% respectively and stabilized until 24 month FU. 18 Month angiographic FU showed a significant decrease in late luminal loss (0.67 ± 0.54, 11.8% reduction or 10% by matched serial analysis, P = 0.001). Conclusion: The HEALING IIB study suggests that statin therapy in combination with the EPC capture stent does not contribute to a reduction of in-stent restenosis formation for the treatment of de novo coronary artery disease. Although concomitant statin therapy was able to stimulate EPC recruitment, it did not improve the angiographic outcome of the bio-engineered EPC capture stent. Remarkably, angiographic late loss was significantly reduced between 6 and 18 months.

The diagnostic value of intracoronary optical coherence tomography (Article)

Regar, E.S. — 2011-07-11T00:00:00Z

Optical coherence tomography (OCT) is a novel light-based imaging modality for application in the coronary circulation. Compared to conventional intravascular ultrasound, OCT has a ten-fold higher image resolution. This advantage has seen OCT successfully applied in the assessment of atherosclerotic plaque, stent apposition, and tissue coverage, heralding a new era in intravascular coronary imaging. The present article discusses the diagnostic value of OCT, both in cardiovascular research as well as in potential clinical application. The unparalleled high image resolution and strong contrast between the coronary lumen and the vessel wall structure enable fast and reliable image interpretation. OCT makes it possible to visualize the presence of atherosclerotic plaque in order to characterize the structure and extent of coronary plaque and to quantify lumen dimensions, as well as the extent of lumen narrowing, in unprecedented detail. Based on optical properties, OCT is able to distinguish different tissue types, such as fibrous, lipid-rich, necrotic, or calcified tissue. Furthermore, OCT is able to cover the visualization of a variety of features of atherosclerotic plaques that have been associated with rapid lesion progression and clinical events, such as thin cap fibroatheroma, fibrous cap thickness, dense macrophage infiltration, and thrombus formation. These unique features allow the use of OCT to assess patients with acute coronary syndrome and to study the dynamic nature of coronary atherosclerosis in vivo and over time. This permits new insights into plaque progression, regression, and rupture, as well as the study of effects of therapies aimed at modulating these developments. Today's OCT technology allows high detail resolution as well as fast and safe clinical image acquisition. These unique features have established OCT as the gold standard for the assessment of coronary stents. This technique makes it possible to study stent expansion, peri-procedural vessel trauma, and the interaction of the stent with the vessel wall down to the level of individual stent struts, both acutely as well as in the long term, where it is has proven extremely sensitive to the detection of even minor amounts of tissue coverage. These qualities render OCT indispensable to addressing vexing clinical questions such as the relationship of drug-eluting stent deployment, vascular healing, the true time course of endothelial stent coverage, and late stent thrombosis. This may also better guide the optimal duration of dual anti-platelet therapy that currently remains unclear and relatively empirical. In the future, OCT might emerge, parallel to its undisputed position in research, as the tool of choice in all clinical scenarios where angiography is limited by its nature as a two-dimensional luminogram.

Primary prevention of cardiovascular diseases: A cost study in family practices (Article)

Bekker-Grob, E.W. de — 2011-07-08T00:00:00Z

Background: Considering the scarcity of health care resources and the high costs associated with cardiovascular diseases, we investigated the spending on cardiovascular primary preventive activities and the prescribing behaviour of primary preventive cardiovascular medication (PPCM) in Dutch family practices (FPs). Methods. A mixed methods design was used, which consisted of a questionnaire (n = 80 FPs), video recordings of hypertension- or cholesterol-related general practitioner visits (n = 56), and the database of Netherlands Information Network of General Practice (n = 45 FPs; n = 157,137 patients). The questionnaire and video recordings were used to determine the average frequency and time spent on cardiovascular primary preventive activities per FP respectively. Taking into account the annual income and full time equivalents of general practitioners, health care assistants, and practice nurses as well as the practice costs, the total spending on cardiovascular primary preventive activities in Dutch FPs was calculated. The database of Netherlands Information Network of General Practice was used to determine the prescribing behaviour in Dutch FPs by conducting multilevel regression models and adjusting for patient and practice characteristics. Results: Total expenditure on cardiovascular primary preventive activities in FPs in 2009 was 38.8 million (2.35 per capita), of which 47% was spent on blood pressure measurements, 26% on cardiovascular risk profiling, and 11% on lifestyle counselling. Fifteen percent (11 per capita) of all cardiovascular medication prescribed in FPs was a PPCM. FPs differed greatly on prescription of PPCM (odds ratio of 3.1). Conclusions: Total costs of cardiovascular primary preventive activities in FPs such as blood pressure measurements and lifestyle counselling are relatively low compared to the costs of PPCM. There is considerable heterogeneity in prescribing behaviour of PPCM between FPs. Further research is needed to determine whether such large differences in prescription rates are justified. Striving for an optimal use of cardiovascular primary preventive activities might lead to similar health outcomes, but may achieve important cost savings.

Gastrin-releasing peptide receptor-based targeting using bombesin analogues is superior to metabolism-based targeting using choline for in vivo imaging of human prostate cancer xenografts (Article)

Schroeder, R.P.J. — 2011-07-01T00:00:00Z

Purpose: Prostate cancer (PC) is a major health problem. Overexpression of the gastrin-releasing peptide receptor (GRPR) in PC, but not in the hyperplastic prostate, provides a promising target for staging and monitoring of PC. Based on the assumption that cancer cells have increased metabolic activity, metabolism-based tracers are also being used for PC imaging. We compared GRPR-based targeting using the68Ga-labelled bombesin analogue AMBA with metabolism-based targeting using18F-methylcholine (18F-FCH) in nude mice bearing human prostate VCaP xenografts. Methods: PET and biodistribution studies were performed with both68Ga-AMBA and18F-FCH in all VCaP tumour-bearing mice, with PC-3 tumour-bearing mice as reference. Scanning started immediately after injection. Dynamic PET scans were reconstructed and analysed quantitatively. Biodistribution of tracers and tissue uptake was expressed as percent of injected dose per gram tissue (%ID/g). Results: All tumours were clearly visualized using68Ga-AMBA.18F-FCH showed significantly less contrast due to poor tumour-to-background ratios. Quantitative PET analyses showed fast tumour uptake and high retention for both tracers. VCaP tumour uptake values determined from PET at steady-state were 6.7±1.4%ID/g (20-30 min after injection, N=8) for68Ga-AMBA and 1.6±0.5%ID/g (10-20 min after injection, N=8) for18F-FCH, which were significantly different (p<0.001). The results in PC-3 tumour-bearing mice were comparable. Biodistribution data were in accordance with the PET results showing VCaP tumour uptake values of 9.5±4.8%ID/g (N=8) for68Ga-AMBA and 2.1±0.4%ID/g (N=8) for18F-FCH. Apart from the GRPR-expressing organs, uptake in all organs was lower for68Ga-AMBA than for18F-FCH. Conclusion: Tumour uptake of68Ga-AMBA was higher while overall background activity was lower than observed for18F-FCH in the same PC-bearing mice. These results suggest that peptide receptor-based targeting using the bombesin analogue AMBA is superior to metabolism-based targeting using choline for scintigraphy of PC.

The magnetic navigation system allows safety and high efficacy for ablation of arrhythmias (Article)

Bauernfeind, T. — 2011-07-01T00:00:00Z

Aims: We aimed to evaluate the safety and long-term efficacy of the magnetic navigation system (MNS) in a large number of patients. The MNS has the potential for improving safety and efficacy based on atraumatic catheter design and superior navigation capabilities. Methods and results: In this study, 610 consecutive patients underwent ablation. Patients were divided into two age- and sex-matched groups. Ablations were performed either using MNS (group MNS, 292) or conventional manual ablation [group manual navigation (MAN), 318]. The following parameters were analysed: acute success rate, fluoroscopy time, procedure time, complications [major: pericardial tamponade, permanent atrioventricular (AV) block, major bleeding, and death; minor: minor bleeding and temporary AV block]. Recurrence rate was assessed during follow-up (15 ± 9.5 months). Subgroup analysis was performed for the following groups: atrial fibrillation, isthmus dependent and atypical atrial flutter, atrial tachycardia, AV nodal re-entrant tachycardia, circus movement tachycardia, and ventricular tachycardia (VT). Magnetic navigation system was associated with less major complications (0.34 vs. 3.2%, P = 0.01). The total numbers of complications were lower in group MNS (4.5 vs. 10%, P = 0.005). Magnetic navigation system was equally effective as MAN in acute success rate for overall groups (92 vs. 94%, P = ns). Magnetic navigation system was more successful for VTs (93 vs. 72%, P < 0.05). Less fluoroscopy was used in group MNS (30 ± 20 vs. 35 ± 25 min, P < 0.01). There were no differences in procedure times and recurrence rates for the overall groups (168 ± 67 vs. 159 ± 75 min, P = ns; 14 vs. 11%, P = ns; respectively). Conclusions: Our data suggest that the use of MNS improves safety without compromising efficiency of ablations. Magnetic navigation system is more effective than manual ablation for VTs. Published on behalf of the European Society of Cardiology. All rights reserved.

Non-invasive diagnostic workup of patients with suspected stable angina by combined computed tomography coronary angiography and magnetic resonance perfusion imaging (Article)

Kirschbaum, S.W.M. — 2011-07-01T00:00:00Z

Background: To evaluate additional adenosine magnetic resonance perfusion (MRP) imaging in the diagnostic workup of patients with suspected stable angina with computed tomography coronary angiography (CTCA) as first-line diagnostic modality. Methods and Results: Two hundred and thirty symptomatic patients (male, 52%; age, 56 year) with suspected stable angina underwent CTCA. In patients with a stenosis of >50% as visually assessed, MRP was performed and the quantitative myocardial perfusion reserve index (MPRI) was calculated. Coronary flow reserve (CFR) using invasive coronary flow measurements served as the standard of reference. CTCA showed non-significant CAD in 151/230 (66%) patients and significant CAD in 79/230 patients (34%), of whom 50 subsequently underwent MRP and CFR. MRP showed reduced perfusion in 32 patients (64%), which was confirmed by CFR in 27 (84%). All 18 cases of normal MRP (36%) were confirmed by CFR. The positive likelihood ratio of MRP for the presence of functional significant disease in patients with a lesion on CTCA was 4.49 (95% confidence interval [CI] 2.12-9.99). The negative likelihood ratio was 0.05 (95%CI 0.01-0.34). Conclusions: CTCA as first-line diagnostic modality excluded coronary artery disease in a high percentage of patients referred for diagnostic workup of suspected stable angina. MRP made a significant contribution to the detection of functional significant lesions in patients with a positive CTCA.

Right ventricular outflow tract reconstruction with an allograft conduit in patients after tetralogy of fallot correction: Long-term follow-up (Article)

Woestijne, P.C. van de — 2011-07-01T00:00:00Z

Background: In tetralogy of Fallot (TOF) pulmonary regurgitation is a frequent complication after initial repair. The objective of the present study was to describe the long-term experience with the use of allograft conduits for right ventricular outflow tract (RVOT) reconstruction after correction of TOF in our institution. Methods: Between 1987 and 2009, 133 allografts were implanted in 126 patients (mean age, 27.8 years). The mean time from initial TOF repair to allograft implantation was 20.8 ± 8.8 years. Kaplan-Meier analyses were done for patient survival, freedom from allograft replacement and freedom from any cardiovascular event. Results: Hospital mortality was 1.5% (2 patients). Mean follow-up was 8.1 years. Ten other patients died during late follow-up, in 8 patients the cause was heart failure. Patient survival was 95% at 5 years, 91% at 10 years, and 80% at 15 years. Male sex, older patient age at the time of operation, and the use of preoperative diuretics were associated with increased risk of mortality during follow-up. Freedom from allograft replacement was 83% at 10 years and 70% at 15 years. Freedom from any valve-related event was 80% at 10 years and 67% at 15 years. Conclusions: Right ventricular outflow tract reconstruction after previous TOF repair can be performed with low risk and a low reintervention rate. Allograft conduits function satisfactorily in the pulmonary position at longer-term follow-up. Functional status after allograft implantation in patients with a previous correction of TOF remains good. There is concern about the long-term survival and the occurrence of heart failure.

Stabilisation of atherosclerotic plaques position paper of the european society of cardiology (ESC) working group on atherosclerosis and vascular biology (Article)

Ylä-Herttuala, S. — 2011-07-01T00:00:00Z

Plaque rupture and subsequent thrombotic occlusion of the coronary arteryaccount for as many as three quarters of myocardial infarctions. Theconcept of plaque stabilisation emerged about 20 years ago to explainthe discrepancy between the reduction of cardiovascular events in patientsreceiving lipid lowering therapy and the small decrease seen in angiographicevaluation of atherosclerosis. Since then, the concept of a vulnerableplaque has received a lot of attention in basic and clinical researchleading to a better understanding of the pathophysiology of thevulnerable plaque and acute coronary syndromes. From pathological andclinical observations, plaques that have recently ruptured have thin fibrouscaps, large lipid cores, exhibit outward remodelling and invasion byvasa vasorum. Ruptured plaques are also focally inflamed and this maybe a common denominator of the other pathological features. Plaqueswith similar characteristics, but which have not yet ruptured, are believ ed to be vulnerable to rupture. Experimental studies strongly support thevalidity of anti-inflammatory approaches to promote plaque stability. Unfortunately,reliable non-invasive methods for imaging and detection ofsuch plaques are not yet readily available. There is a strong biologicalbasis and supportive clinical evidence that low-density lipoprotein loweringwith statins is useful for the stabilisation of vulnerable plaques. Thereis also some clinical evidence for the usefulness of antiplatelet agents,beta blockers and renin-angiotensin-aldosterone system inhibitors forplaque stabilisation. Determining the causes of plaque rupture and designingdiagnostics and interventions to prevent them are urgent prioritiesfor current basic and clinical research in cardiovascular area.

Exercise training does not improve cardiac function in compensated or decompensated left ventricular hypertrophy induced by aortic stenosis (Article)

Deel, E.D. van — 2011-06-01T00:00:00Z

There is ample evidence that regular exercise exerts beneficial effects on left ventricular (LV) hypertrophy, remodeling and dysfunction produced by ischemic heart disease or systemic hypertension. In contrast, the effects of exercise on pathological LV hypertrophy and dysfunction produced by LV outflow obstruction have not been studied to date. Consequently, we evaluated the effects of 8 weeks of voluntary wheel running in mice (which mitigates post-infarct LV dysfunction) on LV hypertrophy and dysfunction produced by mild (mTAC) and severe (sTAC) transverse aortic constriction. mTAC produced ~ 40% LV hypertrophy and increased myocardial expression of hypertrophy marker genes but did not affect LV function, SERCA2a protein levels, apoptosis or capillary density. Exercise had no effect on global LV hypertrophy and function in mTAC but increased interstitial collagen, and ANP expression. sTAC produced ~ 80% LV hypertrophy and further increased ANP expression and interstitial fibrosis and, in contrast with mTAC, also produced LV dilation, systolic as well as diastolic dysfunction, pulmonary congestion, apoptosis and capillary rarefaction and decreased SERCA2a and ryanodine receptor (RyR) protein levels. LV diastolic dysfunction was likely aggravated by elevated passive isometric force and Ca2+-sensitivity of myofilaments. Exercise training failed to mitigate the sTAC-induced LV hypertrophy and capillary rarefaction or the decreases in SERCA2a and RyR. Exercise attenuated the sTAC-induced increase in passive isometric force but did not affect myofilament Ca2+-sensitivity and tended to aggravate interstitial fibrosis. In conclusion, exercise had no effect on LV function in compensated and decompensated cardiac hypertrophy produced by LV outflow obstruction, suggesting that the effect of exercise on pathologic LV hypertrophy and dysfunction depends critically on the underlying cause.

Automated analysis of three-dimensional stress echocardiography (Article)

Leung, K.Y.E. — 2011-06-01T00:00:00Z

Real-time three-dimensional (3D) ultrasound imaging has been proposed as an alternative for two-dimensional stress echocardiography for assessing myocardial dysfunction and underlying coronary artery disease. Analysis of 3D stress echocardiography is no simple task and requires considerable expertise. In this paper, we propose methods for automated analysis, which may provide a more objective and accurate diagnosis. Expert knowledge is incorporated via statistical modelling of patient data. Methods for identifying anatomical views, detecting endocardial borders, and classification of wall motion are described and shown to provide favourable results. We also present software developed especially for analysis of 3D stress echocardiography in clinical practice. Interobserver agreement in wall motion scoring is better using the dedicated software (96%) than commercially available software not dedicated for this purpose (79%). The developed tools may provide useful quantitative and objective parameters to assist the clinical expert in the diagnosis of left ventricular function.

Anhedonia is associated with poor health status and more somatic and cognitive symptoms in patients with coronary artery disease (Article)

Pelle, A.J. — 2011-06-01T00:00:00Z

Purpose: The effectiveness of cardiac rehabilitation (CR) in patients with coronary artery disease (CAD) is moderated by negative emotions and clinical factors, but no studies evaluated the role of positive emotions. This study examined whether anhedonia (i.e. the lack of positive affect) moderated the effectiveness of CR on health status and somatic and cognitive symptoms. Methods: CAD patients (n = 368) filled out the Hospital Anxiety and Depression Scale (HADS) to assess anhedonia at the start of CR, and the Short-Form Health Survey (SF-36) and the Health Complaints Scale (HCS) at the start of CR and at 3 months to assess health status and somatic and cognitive symptoms, respectively. Results: Adjusting for clinical and demographic factors, health status improved significantly during the follow-up (F(1,357) = 10.84, P = .001). Anhedonic patients reported poorer health status compared with non-anhedonic patients, with anhedonia exerting a stable effect over time (F(1,358) = 34.80, P < .001). Somatic and cognitive symptoms decreased over time (F(1,358) = 3.85, P = .05). Anhedonics experienced more benefits in terms of somatic and cognitive symptoms over time (F(1,358) = 13.00, P < .001). Conclusion: Anhedonic patients reported poorer health status and higher levels of somatic and cognitive symptoms prior to and after CR. Somatic and cognitive symptoms differed as a function of anhedonia over time, but health status did not. Anhedonia might provide a new avenue for secondary prevention in CAD.

A clinical prediction rule for the diagnosis of coronary artery disease: Validation, updating, and extension (Article)

Genders, T.S.S. — 2011-06-01T00:00:00Z

AimsThe aim was to validate, update, and extend the DiamondForrester model for estimating the probability of obstructive coronary artery disease (CAD) in a contemporary cohort. Methods and resultsProspectively collected data from 14 hospitals on patients with chest pain without a history of CAD and referred for conventional coronary angiography (CCA) were used. Primary outcome was obstructive CAD, defined as <50 stenosis in one or more vessels on CCA. The validity of the DiamondForrester model was assessed using calibration plots, calibration-in-the-large, and recalibration in logistic regression. The model was subsequently updated and extended by revising the predictive value of age, sex, and type of chest pain. Diagnostic performance was assessed by calculating the area under the receiver operating characteristic curve (c-statistic) and reclassification was determined. We included 2260 patients, of whom 1319 had obstructive CAD on CCA. Validation demonstrated an overestimation of the CAD probability, especially in women. The updated and extended models demonstrated a c-statistic of 0.79 (95 CI 0.770.81) and 0.82 (95 CI 0.800.84), respectively. Sixteen per cent of men and 64 of women were correctly reclassified. The predicted probability of obstructive CAD ranged from 10 for 50-year-old females with non-specific chest pain to 91 for 80-year-old males with typical chest pain. Predictions varied across hospitals due to differences in disease prevalence. Conclusion Our results suggest that the DiamondForrester model overestimates the probability of CAD especially in women. We updated the predictive effects of age, sex, type of chest pain, and hospital setting which improved model performance and we extended it to include patients of 70 years and older.

Test-retest variability of volumetric right ventricular measurements using real-time three-dimensional echocardiography (Article)

Zwaan, H.B. van der — 2011-06-01T00:00:00Z

Background: Substantial variability in sequential echocardiographic right ventricular (RV) quantification may exist. Interobserver and intraobserver values are well known, but acquisition (test-retest) variability has been rarely assessed. The objective of this study was to determine the test-retest variability of sequential RV volume and ejection fraction (EF) measurements by real-time three-dimensional echocardiography in patients with congenital heart disease and healthy controls. Methods: Twenty-eight participants (21 patients with congenital heart disease, seven healthy controls; mean age, 30 ± 14 years; 43% men) underwent a series of three echocardiographic studies. To obtain interobserver and intraobserver test-retest variability, two sonographers acquired sequential RV data sets in each participant during one outpatient visit. RV volumetric quantification was done using semiautomated three-dimensional border detection. The variability data were analyzed using correlation coefficients, Bland-Altman analysis, and coefficients of variation. Results: Absolute mean differences for sequential intraobserver acquisitions were 12 ± 12 mL for end-diastolic volume, 7 ± 6 mL for end-systolic volume, and 4 ± 3% for EF. Interobserver and intraobserver test-retest variability, respectively, were 7% and 7% for RV end-diastolic volume, 14% and 7% for end-systolic volume, and 8% and 6% for EF. Conclusions: Good test-retest variability, besides the practical nature of real-time three-dimensional echocardiography for RV volume and EF assessment, makes it a valuable technique for serial follow-up. Although it may be challenging to diminish all factors that can influence echocardiographic examination for serial follow-up, standardization of RV size and functional measurements should be a goal to produce more interchangeable data. Copyright 2011 by the American Society of Echocardiography.

Ultrafast selective quantification of methotrexate in human plasma by high-throughput MALDI-isotope dilution mass spectrometry (Article)

Meesters, R.J.W. — 2011-06-01T00:00:00Z

Background: A new analytical MS method using isotope dilution combined with MALDI-triple quadrupole MS/MS has been developed and validated for the determination of methotrexate and 7-hydroxymethotrexate in plasma. Methotrexate, methotrexate-d3, 7-hydroxymethotrexate and 7-hydroxymethotrexate-d3 were monitored by selected reaction monitoring using the transitions m/z 455.2→308.2, 458.2→311.2, 471.2→324.2 and 474.2→327.2 for methotrexate, methotrexate-d3, 7-hydroxymethotrexate and 7-hydroxymethotrexate- d3, respectively. Results: The LLOQ was 1 nmol/l for methotrexate and 7-hydroxymethotrexate while the limit of detection was 0.3 nmol/l for both analytes. The new developed method was cross-validated by a fluorescence polarization immunoassay and tested for its clinical feasibility by measuring plasma samples from patients suffering from acute lymphoblastic leukemia. Plasma methotrexate concentrations ranged between 66.0 and 954 nmol/l and observed 7-hydroxymethotrexate/methotrexate ratios ranged between 0.1 and 32.4, respectively. Conclusion: The new method showed comparable analytical performances as the fluorescence polarization immunoassay, but analyte specificity and sensitivity of the newly developed method were significantly better.

A crucial factor in shared decision making: The team approach (Article)

Head, S.J. — 2011-05-28T00:00:00Z

Cardiac Magnetic Resonance Imaging in Ischemic Heart Disease (Doctoral Thesis)

Kirschbaum, S.W.M. — 2011-05-20T00:00:00Z

Ischemic heart disease is the leading cause of morbidity and mortality in the western world in particularly in the elderly and as medical and revascularization therapy is improving and life expectancy is increasing, the number of patients having ischemic heart disease is expected to increase. Chronic ischemic heart disease may be associated with depressed left ventricular function due to a state called ‘hibernation” or “sleeping” myocardium or scarred myocardium. Scarred myocardium will not improve after revascularization therapy but hibernating myocardium may recover after restoration of myocardial blood flow. The time of blood flow obstruction and the extent of myocardial damage is related to the ability of ischemic myocardium to improve. Therefore early accurate assessment of viability and necrosis is important for optimal management of patients with chronic ischemic heart disease.

Relationship between cardiovascular risk factors and biomarkers with necrotic core and atheroma size: a serial intravascular ultrasound radiofrequency data analysis (Article)

Garcia-Garcia, H.M. — 2011-05-19T00:00:00Z

We explored the impact of patient demographics, anthropometric measurements, cardiovascular risk factors, and soluble biomarkers on necrotic core and atheroma size in patients with coronary disease. The IBIS-2 trial enrolled 330 patients. In the multivariate analysis, at baseline, creatinine had a positive, whereas baseline mean lumen diameter and myeloperoxidase had a negative, independent association with percentage of necrotic core (PNC); while age, glomerular filtration rate <60, HbA1c, previous PCI or CABG and baseline % diameter stenosis were positively, and acute coronary syndromes (ACS) were negatively associated with baseline percentage atheroma volume (PAV). The variables associated with a decrease in PNC from baseline were darapladib, ACS and a large content of NC at baseline, while variables associated with an increase in PNC were previous stroke and % diameter stenosis at baseline. Those variables associated with a decrease in PAV from baseline were waist circumference, statin use, CD40L and baseline PAV, while the only variable associated with an increase in PAV was baseline diastolic blood pressure. Treatment with darapladib was associated with a decrease in necrotic core, but was not associated with a decrease in percentage atheroma volume. On the contrary, statin use was only associated with a decrease in percentage atheroma volume.

Cardiac magnetic resonance imaging in stable ischaemic heart disease (Article)

Kirschbaum, S.W.M. — 2011-05-16T00:00:00Z

Cardiac magnetic resonance imaging (CMR) is a new robust versatile non-invasive imaging technique that can detect global and regional myocardial dysfunction, presence of myocardial ischaemia and myocardial scar tissue in one imaging session without radiation, with superb spatial and temporal resolution, inherited three-dimensional data collection and with relatively safe contrast material. The reproducibility of CMR is high which makes it possible to use this technique for serial assessment to evaluate the effect of revascularisation therapy in patients with ischaemic heart disease.