Biomarkers in outpatient heart failure management; Are they correlated to and do they influence clinical judgment?

AIMS: Heart failure (HF) management is complicated by difficulties in clinical assessment. Biomarkers may help guide HF management, but the correspondence between clinical evaluation and biomarker serum levels has hardly been studied. We investigated the correlation between biomarkers and clinical signs and symptoms, the influence of patient characteristics and comorbidities on New York Heart Association (NYHA) classification and the effect of using biomarkers on clinical evaluation. METHODS AND RESULTS: This post-hoc analysis comprised 622 patients (77 ± 8 years, 76 % NYHA class ≥3, 80 % LVEF ≤45 %) participating in TIME-CHF, randomising patients to either NT-proBNP-guided or symptom-guided therapy. Biomarker measurements and clinical evaluation were performed at baseline and after 1, 3, 6, 12 and 18 months. NT-proBNP, GDF-15, hs-TnT and to a lesser extent hs-CRP and cystatin-C were weakly correlated to NYHA, oedema, jugular vein distension and orthopnoea (ρ-range: 0.12-0.33; p < 0.01). NT-proBNP correlated more strongly to NYHA class in the NT-proBNP-guided group compared with the symptom-guided group. NYHA class was significantly influenced by age, body mass index, anaemia, and the presence of two or more comorbidities. CONCLUSION: In HF, biomarkers correlate only weakly with clinical signs and symptoms. NYHA classification is influenced by several comorbidities and patient characteristics. Clinical judgement seems to be influenced by a clinician's awareness of NT-proBNP concentrations.

Key factors influencing the implementation success of a home telecare application.

RATIONALE: The introduction of home telecare in healthcare organizations has shown mixed results in practice. The aim of this study is to arrive at a set of key factors that can be used in further implementation of video communication. We argue that key factors are mainly found in the organizational climate for home telecare implementation, the characteristics of the implementation strategy and the available technology. METHODS: Interviews were conducted in three care organizations with 27 respondents of different levels within and outside the organization. Implementation determinants, based on earlier research, were used as a categorization framework for the interviews. RESULTS: We found that most prominent factors influencing implementation outcomes relate to the stability of the technical and the external environment and the alignment of organization, goals and implementation strategy. CONCLUSION: Because of the experimental nature of implementing video communication, attention to telecare influencers has been inconsistent and disorganized but it is becoming increasingly important. According to the respondents, a champion-led roll-out is imperative for implementation in order to advance to the next stage in home telecare and to organize services for substitution of care.

Origin and reduction of motion and f0 artifacts in high resolution T2*-weighted magnetic resonance imaging: application in Alzheimer's disease patients.

The altered iron concentration in many neurodegenerative diseases such as Alzheimer's disease (AD) has led to the development of MRI sequences that are sensitive to the accompanying changes in the transverse relaxation rate. Heavily T(2)*-weighted imaging sequences at high magnetic field strength (7T and above), in particular, show potential for detecting small changes in iron concentration. However, these sequences require a long echo time in combination with a long scanning time for high resolution and are therefore prone to image artifacts caused by physiological fluctuations, patient motion or system instabilities. Many groups have found that the high image quality that was obtained using high resolution T(2)*-weighted sequences at 7T in healthy volunteers, could not be obtained in AD patients. In this study the source of the image artifacts was investigated in phantom and in healthy volunteer experiments by incorporating movement parameters and resonance frequency (f0) variations which were measured in AD patients. It was found that image degradation caused by typical f0 variations was a factor-of-four times larger than artifacts caused by movement characteristic of AD patients in the scanner. In addition to respiratory induced f0 variations, large jumps in the f0 were observed in AD patients. By implementing a navigator echo technique to correct for f0 variations, the image quality of high resolution T(2)*-weighted images increased considerably. This technique was successfully applied in five AD patients and in five subjective memory complainers. Visual scoring showed improvements in image quality in 9 out of 10 subjects. Ghosting levels were reduced by 24+/-13%.

Development and testing of passive tracking markers for different field strengths and tracking speeds.

Susceptibility markers for passive tracking need to be small in order to maintain the shape and mechanical properties of the endovascular device. Nevertheless, they also must have a high magnetic moment to induce an adequate artefact at a variety of scan techniques, tracking speeds and, preferably, field strengths. Paramagnetic markers do not satisfy all of these requirements. Ferro- and ferrimagnetic materials were therefore investigated with a vibrating sample magnetometer and compared with the strongly paramagnetic dysprosium oxide. Results indicated that the magnetic behaviour of stainless steel type AISI 410 corresponds the best with ideal marker properties. Markers with different magnetic moments were constructed and tested in in vitro and in vivo experiments. The appearance of the corresponding artefacts was field strength independent above magnetic saturation of 1.5 T. Generally, the contrast-to-noise ratio decreased at increasing tracking speed and decreasing magnetic moment. Device depiction was most consistent at a frame rate of 20 frames per second.

Magnetic resonance techniques in hemodialysis access management.

In this review we describe current applications and future perspectives of MR angiography, MR flow quantification, and interventional MRI in hemodialysis access management. Each section starts with a brief overview of the main techniques that are currently available or under development. This is followed by a survey of the pertinent literature. Each section concludes with a discussion of the reported findings and an indication of research opportunities.

Is the diet of patients with interstitial cystitis related to their disease?

OBJECTIVE: The dietary habits of interstitial cystitis (IC) patients compared to the average food and fluid consumption of the general population were evaluated and any spontaneous preference or avoidance of specific foodstuffs and fluids of IC patients was investigated. METHODS: A verbal interview with 16 IC patients provided information on the consumption of foodstuffs and fluids as well as dietary habits. Prior to the dietary interview none of the IC patients were aware of any possible dietary measures in relation to their IC symptoms. The results were compared to the averages of the general population. RESULTS: IC patients consumed statistically significantly less calories and fat (p < 0.05), and statistically significantly more fibers (p < 0.01) than the general population. Among the IC patients there were significantly fewer consumers of coffee (p < 0.01) and significantly more consumers of (herbal) tea (p < 0.05). The difference in orange juice consumption was not significant. CONCLUSIONS: According to general standards, IC patients had a more healthy daily diet than the general population. The observation that IC patients consumed less coffee (caffeine) than the general population is consistent with previous reports on irritative IC symptoms exacerbating after caffeine consumption. No rationale for other dietary or fluid intake changes was found.

Comparison of four bifunctional reagents for coupling peptides to proteins and the effect of the three moieties on the immunogenicity of the conjugates.

Peptide-carrier conjugates are widely used to raise antipeptide antibodies. In a model system using angiotensin and tetanus toxoid as the peptide and the carrier protein respectively, four cross-linking reagents were employed to study their effect on the immunogenicity of the conjugates. Optimization of the conjugation method for these heterobifunctional reagents, all succinimidyl active esters, resulted in well-defined conjugates of predictable composition. ELISA assays were performed to compare the antigenicity and the immunogenicity of the conjugates. The antipeptide antibody titres were of the order of 2 X 10(4)-2 X 10(5). The anti-carrier antibody titres were high, in spite of the modification of the protein. Three of the four coupling reagents used for conjugation were of the 'maleimide' type: succinimidyl 6-(N-maleimido)-n-hexanoate (MHS), succinimidyl 4-(N-maleimidomethyl)-cyclohexane-1-carboxylate (SMCC) and succinimidyl m-maleimidobenzoate (MBS). One coupling reagent contained an activated disulphide: succinimidyl 3-(2-pyridyldithio)propionate (SPDP). The constrained linkers originating from SMCC and MBS induced very high linker-specific antibody levels. The more flexible non-aromatic linkers originating from MHS and SPDP showed almost no reactivity. For this reason and since the thioether linkage is more stable than the disulphide bond, we recommend MHS as the crosslinking reagent of choice.

[Regional blood flow and oxygen consumption in the leg muscles of normal subjects and in those with arterial insufficiency. Study of the distribution of C15O2 and of 15O2 using positron emission tomography]. / Débit sanguin régional et extraction de l'oxygène dans les muscles de la jambe chez le sujet normal et l'insuffisant artériel. Etude de la distribution du C15O2 et de l'15O2 par tomographie à émission de positons.

We first studied the distribution of radioactivity during continuous inhalation of C15O2 and 15O2 in traverse tomograms of the greatest diameter of legs, at rest and immediately after exercise (ankle flexions). C15O2 and 15O2 were distributed homogeneously and symmetrically in both legs of normal subjects at rest. The activity accumulated in the anterolateral region after exercise. In patients, this pattern of distribution was similar but asymmetrical, depending on the arterial pathology. No systematic distribution of either C15O2 or 15O2 was observed. In a second step, we studied quantitatively blood flow (F), oxygen uptake (R) and oxygen extraction (E) in 11 subjects: 5 normals (23 +/- 1 years) and 6 patients (60 +/- 11 years) suffering from unilateral intermittent claudication. We used the bolus inhalation technique of C15O2 and 15O2. In the normal leg at rest, ranges were 2.5 to 8.0 ml/min.hg for F, 0.9 to 21.3 mumol/min.hg for R and 3.6 to 33.4% for E. In the pathological leg at rest, ranges were 3.7 to 11.3 ml/min.hg for F, 3.8 to 10.6 mumol/min.hg for R and 7.1 to 24.5% for E. After exercise, ranges were 6.4 to 62.8 ml/min.hg for F, 66.0 to 386.3 mumol/min.hg for R and 29.2 to 89.5% for E in both legs. There was no straight difference between normal and pathological legs soon after exercise. This study allows us to expect that the demonstration of such a difference implies a longer delay of data acquisition following the slow post-ischemia recovery.