| 21. |
- Hayashi, Shirley Yumi, et al.
(författare)
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Improvement of cardiac function after haemodialysis : Quantitative evaluation by colour tissue velocity imaging
- 2004
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Ingår i: Nephrology, Dialysis and Transplantation. - : Oxford University Press (OUP). - 0931-0509 .- 1460-2385. ; 19:6, s. 1497-1506
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Tidskriftsartikel (refereegranskat)abstract
- Background. Overhydration and accumulation of uraemic toxins may influence the myocardial function in haemodialysis (HD) patients. To evaluate cardiac function and the effects of fluid and solute removal during a single session of HD, colour tissue velocity imaging (TVI) was used. This new technique, which is less load dependent than conventional echocardiography, allows an objective quantitative assessment of myocardial contractility, contraction and relaxation. Methods. Conventional echocardiographic and TVI images were recorded before and after a single HD session in 13 clinically stable HD patients (62 +/- 10 years, six males) and in 13 sex- and age-matched healthy controls. Myocardial tissue velocities (v; cm/s) for isovolumetric contraction (IVC), peak systole (PS), early (E) and late (A') diastolic filling and strain rate (SR) were measured. Results. Left ventricular hypertrophy (LVH) was present in 12 patients. TVI gave additional information in comparison with conventional echocardiography. Before HD, PS (5.0 +/- 0.8 vs 6.0 +/- 1.2 cm/s, P < 0.05), E' (5.7 +/- 1.7 vs 7.3 +/- 2.0 cm/s, P < 0.05) and A' (6.6 +/- 1.7 vs. 8.3 +/- 2.9 cm/s, P < 0.05) velocities were lower in the patients than in the controls, indicating systolic and diastolic dysfunction. The HD session increased IVCv (4.0 +/- 1.7 to 5.5 +/- 1.9 cm/s; P < 0.001), PSv (5.0 +/- 0.8 to 5.7 +/- 0.8 cm/s; P < 0.05) and SR (0.7 +/- 0.2 to 0.9 +/- 0.2 1/s; P < 0.05) and decreased E/E' (16.7 +/- 7.7 to 12.2 +/- 4.0, P < 0.05), indicating improved systolic function and decreased LV filling pressure, respectively. Linear regression analysis demonstrated a dependency of systolic contraction (PSv) and contractility (IVCv) upon plasma levels of phosphate (r(2) = 0.70, P < 0.005, r(2) = 0.33, P < 0.01). Conclusions. Using TVI, HD patients demonstrate myocardial dysfunction, which is found less frequently when using conventional echocardiography. The systolic function seems to be impaired by high plasma levels of phosphate and an increased Ca x P product. One single session of HD improved systolic function as indicated by increases in IVCv, PSv and SR. Further studies are needed to clarify if this effect of HD is due to the acute removal of fluid, the removal of solutes or both.
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| 22. |
- Hayashi, Shirley Yumi, et al.
(författare)
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Left ventricular function in patients with chronic kidney disease evaluated by colour tissue Doppler velocity imaging
- 2006
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Ingår i: Nephrology, Dialysis and Transplantation. - : Oxford University Press (OUP). - 0931-0509 .- 1460-2385. ; 21:1, s. 125-132
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Tidskriftsartikel (refereegranskat)abstract
- Background. Cardiovascular disease is the leading cause of death in chronic kidney disease (CKD) patients. Tissue Doppler velocity imaging (TVI) is a new objective method that accurately quantifies myocardial tissue velocities, deformation, time intervals and left ventricular (LV) filling pressure. In this study, TVI was compared with conventional echocardiography for the assessment of left ventricular (LV) function in pre-dialysis patients with different stages of CKD. The results obtained by TVI were used to analyse possible relationships between LV function and clinical factors such as hyperparathyroidism and hypertension that could influence LV function. Methods. Conventional echocardiography and TVI images were recorded in 40 patients (36 men and 4 women, mean age 60 +/- 14 years, range 28-80 years) and in 27 healthy controls (21 men and 6 women, mean age 58 +/- 17 years, range 28-82 years). Twenty-two patients had mild/moderate CKD (CCr > 29 ml/min; Group 1) and 18 patients had severe CKD (CCr <= 29 ml/min; Group 2). Using TVI, the myocardial tissue velocities (v; cm/s) for isovolumetric contraction (IVCv), peak systole (PSv), early (E') and late (A') diastolic filling velocities as well as strain rate (SR), mitral annulus displacement, isovolumetric relaxation time (IVRT) and LV filling pressure were estimated using TVI. The average of six LV wall measurements was used to evaluate LV global function. Results. Using TVI, we were able to identify significantly more patients with diastolic dysfunction than using conventional echocardiography (33 vs 26, P < 0.05). There was no difference in the prevalence of diastolic dysfunction between Group 1 and 2. However, using TVI, Group 2 CKD patients had lower E' velocities (6.2 +/- 1.9 vs 8.0 +/- 2.9 cm/s, P < 0.05) and higher IVRT (137.4 +/- 13 vs 88.2 +/- 26 ms, P < 0.001) in comparison with controls, indicating more accentuated diastolic dysfunction. Systolic blood pressure (SBP) was associated with E' velocities (rho = -0.68, P < 0.005) and E'/A' was strongly associated with SBP (rho = -0.60; P < 0.01) and PTH (rho = -0.64, P < 0.005) in Group 2. Using conventional echocardiography, there was no difference in the prevalence of systolic and diastolic dysfunction between patients with and without LVH. However, using TVI, patients with LVH had significantly lower IVCv (2.8 +/- 1.3 vs 3.8 +/- 1.5 and 3.8 +/- 1.5 cm/s, P < 0.05) and PSv (5.5 +/- 1.0 vs 6.3 +/- 1.2 and 6.4 +/- 1.3 cm/s, P < 0.05) compared with patients without LVH and controls, and they also had lower E' velocities (7.1 +/- 2.7 vs 8.0 +/- 2.9 cm/s, P < 0.05) compared with controls, indicating disturbances in systolic and diastolic left ventricular function. Conclusions. TVI provided additional information on left ventricular function in CKD patients. In patients with advanced renal failure, TVI revealed more accentuated diastolic dysfunction associated with increased systolic blood pressure (SBP) and increased levels of PTH. TVI also demonstrated disturbances in contractility and contraction in patients with LVH, which could not be detected by conventional echocardiography.
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| 23. |
- Hayashi, Shirley Yumi, et al.
(författare)
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Left ventricular mechanical dyssynchrony in patients with different stages of chronic kidney disease and the effects of hemodialysis
- 2013
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Ingår i: Hemodialysis International. - : Wiley-Blackwell. - 1492-7535 .- 1542-4758. ; 17:3, s. 346-358
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Tidskriftsartikel (refereegranskat)abstract
- Left ventricular (LV) dyssynchrony is a known cause of mortality in patients with heart failure and may possibly play a similar role in patients with chronic kidney disease (CKD) in whom sudden death is one of the most common and as yet not fully explained cause of death. LV synchronicity and its relationship with increased volume load and various biomarkers was analyzed in 145 patients including 53 patients with CKD stages 3 and 4 and in 92 CKD stage 5 patients undergoing hemodialysis (HD) or peritoneal dialysis (PD) using color tissue Doppler imaging and tissue synchronization imaging. The HD patients were evaluated both before and after a single HD session. LV dyssynchrony was defined as a regional difference in time to peak systolic myocardial velocity, between 12 LV segments>105milliseconds. LV dyssynchrony was present in 54% of the patients with no difference between CKD 3 and 4 (58%), HD (48%), and PD (51%). LV dyssynchrony was independently associated with LV mass index and increased estimation of LV end-diastolic pressure. A single HD session resulted in significant changes in LV synchronicity variableswith improvement in 50% of the patientsespecially in patients with higher myocardial systolic velocities and lower LV mass index. Abnormalities in LV synchronicity are highly prevalent in CKD patients already prior to dialysis treatment and are associated with LV hypertrophy, LV dysfunction and load conditions, underlining the importance of volume status for LV synchronicity in CKD patients.
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| 24. |
- Henareh, Loghman, et al.
(författare)
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Disturbed glucose metabolism is associated with left ventricular dysfunction using tissue Doppler imaging in patients with myocardial infarction
- 2007
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Ingår i: Clinical Physiology and Functional Imaging. - 1475-0961 .- 1475-097X. ; 27:1, s. 60-66
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Tidskriftsartikel (refereegranskat)abstract
- Aims: To investigate the association between glucose abnormalities and left ventricular (LV) function assessed by tissue Doppler imaging (TDI) in patients with previous history of myocardial infarction and without known diabetes mellitus. Patients and methods: In a cross-sectional study, 123 patients, aged 31-80 years, with a history of previous myocardial infarction and without known diabetes mellitus were examined with TDI echocardiography. A standard oral glucose test (OGTT) with 75 g of glucose was performed. Results: Two-hour plasma glucose were significantly and negatively associated with TDI parameters such as LV ejection time; early diastolic filling velocity (E'-v); ratio of the early to late diastolic filling velocity (E'/A') and positively associated with regional myocardial performance index (MPI) (P < 0.05). Left ventricular ejection time and MPI were significantly higher; E'/A' and E'-v were significantly lower in patients with disturbed glucose metabolism compared with patients with normal glucose tolerance (P < 0.01). These differences remain significant also when the patients with DM were excluded. Conclusions: The present study demonstrates that disturbed glucose metabolism is associated with more pronounced LV dysfunction using TDI in patients with myocardial infarction. These abnormalities in LV function were more common not only in subjects with diabetes, but also in patients with prediabetic condition, impaired glucose intolerance.
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| 25. |
- Larsson, Matilda, et al.
(författare)
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In-vivo assessment of radial and longitudinal strain in the carotid artery using speckle tracking
- 2010
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Ingår i: 2010 IEEE International Ultrasonics Symposium Proceedings. - : IEEE. - 9781457703829 ; , s. 1328-1331
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Konferensbidrag (refereegranskat)abstract
- Ultrasound-based algorithms are commonly used to assess mechanical properties of arterial walls in studies of arterial stiffness and atherosclerosis. Speckle tracking based techniques used for estimation of myocardial strain can be applied on vessels to estimate strain of the arterial wall. Previous elastography studies in vessels have mainly focused on radial strain measurements, whereas the longitudinal strain has been more or less ignored. However, recently we showed the feasibility of speckle tracking to assess longitudinal strain of the carotid artery in-silico. The aim of this study was to test this methodology in-vivo. Ultrasound images were obtained in seven healthy subjects with no known cardiovascular disease (39 ± 14 years old) and in seven patients with coronary artery disease (CAD), (69 ± 4 years old). Speckle tracking was performed on the envelope detected data using our previous developed algorithm. Radial and longitudinal strains were estimated throughout two cardiac cycles in a region of interest (ROI) positioned in the posterior vessel wall. The mean peak systolic radial and longitudinal strain values from the two heart cycles were compared between the groups using a student's t-test. The mean peak radial strain was -39.1 ± 15.1% for the healthy group and -20.4 ± 7.5% for the diseased group (p = 0.01), whereas the mean peak longitudinal strain was 4.8 ± 1.1% and 3.2 ± 1.6% (p = 0.05) for the healthy and diseased group, respectively. Both peak radial and longitudinal strain values were thus significantly reduced in the CAD patient group. This study shows the feasibility to estimate radial and longitudinal strain in-vivo using speckle tracking and indicates that the method can detect differences between groups of healthy and diseased (CAD) subjects.
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| 26. |
- Larsson, Matilda, et al.
(författare)
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Wave intensity wall analysis: a novel noninvasive method to measure wave inntensity
- 2009
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Ingår i: Heart and Vessels. - : Springer Science and Business Media LLC. - 0910-8327 .- 1615-2573. ; 24, s. 357-365
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Tidskriftsartikel (refereegranskat)abstract
- Wave intensity analysis is a concept providing information about the interaction of the heart and the vascular system. Originally, the technique was invasive. Since then new noninvasive methods have been developed. A recently developed ultrasound technique to estimate tissue motion and deformation is speckle-tracking echocardiography. Speckle tracking-based techniques allow for accurate measurement of movement and deformation variables in the arterial wall in both the radial and the longitudinal direction. The aim of this study was to test if speckle tracking-derived deformation data could be used as input for wave intensity calculations. The new concept was to approximate changes of flow and pressure by deformation changes of the arterial wall in longitudinal and radial directions. Flow changes (dU/dt) were approximated by strain rate (sr, 1/s) of the arterial wall in the longitudinal direction, whereas pressure changes (dP/dt) were approximated by sign reversed strain rate (1/s) in the arterial wall in the radial direction. To validate the new concept, a comparison between the newly developed Wave Intensity Wall Analysis (WIWA) algorithm and a commonly used and validated wave intensity system (SSD-5500, Aloka, Tokyo, Japan) was performed. The studied population consisted of ten healthy individuals (three women, seven men) and ten patients (all men) with coronary artery disease. The present validation study indicates that the mechanical properties of the arterial wall, as measured by a speckle tracking-based technique are a possible input for wave intensity calculations. The study demonstrates good visual agreement between the two systems and the time interval between the two positive peaks (W1-W2) measured by the Aloka system and the WIWA system correlated for the total group (r = 0.595, P < 0.001). The correlation for the diseased subgroup was r = 0.797, P < 0.001 and for the healthy subgroup no significant correlation was found (P > 0.05). The results of the study indicate that the mechanical properties of the arterial wall could be used as input for wave intensity calculations. The WIWA concept is a promising new method that potentially provides several advantages over earlier wave intensity methods, but it still has limitations and needs further refinement and larger studies to find the optimal clinical use.
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| 27. |
- Lind, Anna-Britta, et al.
(författare)
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Gene expression of cytochrome P450 1B1 and 2D6 in leukocytes in human pregnancy
- 2003
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Ingår i: Pharmacology and Toxicology. - : Wiley. - 0901-9928 .- 1600-0773. ; 92:6, s. 295-9
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Tidskriftsartikel (refereegranskat)abstract
- We investigated the influence of human pregnancy on gene expression of two cytochrome P450 enzymes in white blood cells. Cytochrome P450 1B1 (CYP1B1) catalyses oestradiol 4-hydroxylation, and may participate in the endocrine regulation of oestrogens. Cytochrome P450 2D6 (CYP2D6) metabolises many commonly used drugs, and previous studies have suggested that it is induced during pregnancy. CYP1B1 and CYP2D6 were therefore considered to be of interest in human pregnancy. As it is not ethically possible to take liver biopsies from healthy mothers during pregnancy, easily accessible cells that express the genes were used as a surrogate tissue. White blood cells were collected from eighteen pregnant women, and were used to measure CYP1B1 and CYP2D6 ribonucleic acid (RNA). The analysis was repeated after pregnancy, the women, thus, serving as their own controls. Real-time reverse transcriptase - polymerase chain reaction methods were used with 18S ribosomal RNA as an internal control. A slight, but not significant, increase in gene activity of CYP1B1 was detected during pregnancy. Expression of CYP2D6 in blood was extremely low, and induction of CYP2D6 during pregnancy could not be confirmed. In conclusion, gene expression of CYP1B1 and CYP2D6 in leukocytes was not significantly up-regulated in the third trimester of pregnancy, but a trend indicating an altered metabolism during pregnancy was detected.
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| 28. |
- Lind, Anna-Britta, et al.
(författare)
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Steady-state concentrations of mirtazapine, N-desmethylmirtazapine, 8-hydroxymirtazapine and their enantiomers in relation to cytochrome P450 2D6 genotype, age and smoking behaviour
- 2009
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Ingår i: Clinical Pharmacokinetics. - : Springer Science and Business Media LLC. - 0312-5963 .- 1179-1926. ; 48:1, s. 63-70
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Tidskriftsartikel (refereegranskat)abstract
- Background and objective: Mirtazapine is a tetracyclic antidepressant drug available as a racemic mixture of S(+)- and R(-)-mirtazapine. These enantiomers have different pharmacological properties, and both contribute to the clinical and adverse effects of the drug. Cytochrome P450 (CYP) 2D6 has been implicated in the metabolism of S(+)-mirtazapine. However, the effect of CYP2D6 on serum concentrations of the enantiomers of mirtazapine and its metabolites has not been assessed in patients on long-term treatment. The main objective of the study was to evaluate the effect of the CYP2D6 genotype on enantiomeric steady-state trough serum concentrations of mirtazapine and its metabolites N-desmethylmirtazapine and 8-hydroxymirtazapine. The effects of sex, age and smoking behaviour were also assessed. Subjects and methods: The study included 95 patients who had depression according to the Diagnostic and Statistical Manual of Mental Disorders - 4th Edition and were treated for 4 weeks with a daily dose of mirtazapine 30 mg. The serum concentrations of the enantiomers of mirtazapine and its metabolites were analysed by liquid chromatography-mass spectrometry, and the subjects were genotyped for CYP2D6 alleles*3, *4,*5 and*6 and gene duplication. Results: Three subjects (3%) were classified as ultrarapid metabolizers (UMs), 56 (59%) as homozygous extensive metabolizers (EMs), 30 (32%) as heterozygous EMs and 6 (6%) as poor metabolizers (PMs) of CYP2D6. The median trough serum concentrations of S(+)-mirtazapine were higher in PMs (59 nmol/L, p = 0.016) and in heterozygous EMs (39 nmol/L, p = 0.013) than in homozygous EMs (28 nmol/L). PMs and heterozygous EMs also had higher mirtazapine S(+)/R(-) ratios (0.4) than homozygous EMs (0.3, p = 0.015 and 0.004, respectively). The S(+)-N-desmethylmirtazapine concentration was higher in PMs (16 nmol/L) than in homozygous EMs (7 nmol/L, p = 0.043). There was an association between the CYP2D6 genotype and the ratio between S(+)-8-hydroxymirtazapine and S(+)-mirtazapine, with a significantly higher ratio in homozygous EMs than in heterozygous EMs (0.11 vs 0.05, p = 0.007). The influence of the CYP2D6 genotype on S(+)-mirtazapine, the mirtazapine S(+)/R(-) ratio and S(+)-N- desmethylmirtazapine remained significant after correction for the influence of sex, age and smoking. Smokers had significantly lower concentrations of S(+)-mirtazapine (23 vs 39 nmol/L, p = 0.026) and R(-)-N-desmethylmirtazapine (39 vs 51 nmol/L, p = 0.036) and a significantly lower mirtazapine S(+)/R(-) ratio (0.28 vs 0.37, p = 0.014) than nonsmokers, and the effect of smoking remained significant after multivariate analysis. Conclusions: This study is the first to show the impact of the CYP2D6 genotype on steady-state serum concentrations of the enantiomers of mirtazapine and its metabolites. Our results also support the role of CYP1A2 in the metabolism of mirtazapine, with lower serum concentrations in smokers than in nonsmokers.
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| 29. |
- Lind, Britta
(författare)
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Evaluation of isovolumic myocardial motions in human subjects using tissue velocity echocardiography
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Colour-coded tissue velocity imaging (TVE) with Echocardiography is an established method for evaluation of the global cardiac function and of the regional myocardial movements. The TVE-technique allows measurements of velocity and deformation variables from any discrete point in the myocardial wall during the cardiac cycle with high temporal and longitudinal spatial resolution. Even the rapid kinetic events during the isovolumic phases can be analysed which has been reported to be involved in the process of pre and postsystolic ventricular reshaping. However, the optimal sampling requirements for a proper rendering of the tissue velocity variables and the effect of different temporal smoothing filters incorporated in the WE software have not yet been established. The aims for current thesis were to establish optimal values for temporal resolution and also to study the effect of temporal filtering algorithms on colour-coded tissue derived duration and velocity variables registered at the base of left ventricle in apical views. After ensuring adequate sampling rate and temporal filter width for the myocardial velocity profiles the isovolumic periods were analysed in fortynine healthy subjects to describe normal reference values in the base of four different cardiac walls. The influence of gender and age were also studied for isovolumic time, velocity variables as well their respectively amplitude motion. The reproducibility for the longitudinal and radial myocardial velocity and displacement variables was studied and varied between 5-12% (CV). The temporal resolution should at least 100 frames/s for a proper rendering of the myocardial velocity variables during the entire cardiac cycle. Increased temporal filter width affected the results by decreased myocardial velocities and the effect was most pronounced during the rapid isovolumic events. The longitudinal motions of left ventricular wall showed biphasic patterns during the isovolumic contraction and relaxation periods and the segmental velocities and displacements differs among the four walls. The relative myocardial isovolumic displacement was most pronounced in anterior wall (5.0 of the total longitudinal myocardial shortening). Except prolonged duration of the TVE-IVRT in the older age group, no other larger gender and age differences occurred.
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| 30. |
- Lind, Britta, et al.
(författare)
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Left ventricular isovolumic velocity and duration variables calculated from colour-coded myocardial velocity images in normal individuals
- 2004
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Ingår i: European Journal of Echocardiography. - : Oxford University Press (OUP). - 1525-2167 .- 1532-2114. ; 5:4, s. 284-293
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Tidskriftsartikel (refereegranskat)abstract
- Aims: To describe the normal myocardial velocity profile during the isovolumic contraction and relaxation period at four different locations within left ventricular base and to establish normal age and gender related isovolumic time and velocity values. Methods and results: In 49 healthy individuals (26 women/23 men) in age groups 21-49 and 50-76 years, tissue velocity profiles and 2D-data were acquired at high temporal resolution (90-147 frames/s) for a subsequent off-line analysis using software enabling retrieval of myocardial Doppler velocity and 2D/anatomical M-mode information from different cardiac locations during the same cardiac cycle. The obtained velocity curves during the isovolumic contraction and relaxation period were usually biphasic and displayed clear regional differences in their respective positive and negative maximal velocities. Besides some gender related differences, mainly in the duration of the positive and negative velocity wave components during the isovolumic contraction period, a clear age-dependent increase in the duration of the isovolumic relaxation phase and its negative and positive velocity components was observed. Conclusion: Modern tissue Doppler imaging supplemented by anatomical M-mode images of the mitral and aortic valve movements allows a proper analysis of the rapid isovolumic myocardial movements. The presented normal isovolumic time and velocity values may prove useful for studies of myocardial function.
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