Dan Liu

Universität Würzburg, Würzburg, Bavaria, Germany

Are you Dan Liu?

Claim your profile

Publications (9)36.96 Total impact

  • Article: Two-dimensional speckle tracking as a non-invasive tool for identification of myocardial fibrosis in Fabry disease.
    [show abstract] [hide abstract]
    ABSTRACT: AimsThis cross-sectional study aimed to analyse myocardial deformation in patients with Fabry disease (FD) in order to evaluate speckle tracking as a method for non-invasive determination of myocardial fibrosis. Myocardial fibrosis is common in Fabry cardiomyopathy and is associated with disease progression and severe prognosis.Methods and resultsIn 101 consecutive Fabry patients (39.8 ± 12.9 years; 42 males), the quantitative measurement of myocardial fibrosis with magnetic resonance imaging was compared with regional myocardial deformation assessed by speckle-tracking imaging. Patients were analysed in relation to per cent of late-enhancement (LE)-positive areas of left-ventricular (LV) mass. Fifty-two patients (51%) displayed LE with a mean volume of 1.2 ± 1.8% of total LV mass. Predominantly basal lateral and posterior segments were affected. Patients with LE had lower global systolic longitudinal strain than those without (LE -14.8 ± 3.5% and -18.9 ± 2.1%, respectively; P < 0.001). Loss of global deformation, quantified by speckle tracking, was predominantly caused by basal posterior (P = 0.049) and lateral (P = 0.005) segments and global systolic strain correlated with the amount of LE (r = 0.543; P < 0.001). Patients with severe LE (>2%, n = 22) showed the lowest deformation values (-5.9 ± 8.4%) in basal postero-lateral segments when compared with those with mild (<2%; n = 30, -7.1 ± 7.5%) or no LE (n = 49, -16.3 ± 3.3%). These changes were accompanied by thinning of the posterior wall and a decrease in diastolic function, whereas ejection fraction and LV end-diastolic diameter were not different. Receiver operating characteristic analysis revealed that the systolic strain of basal postero-lateral segments was the most powerful predictor to distinguish between patients with and without LE (sensitivity = 90%; specificity = 97%, area under the curve = 0.913; P < 0.001).Conclusions Late enhancement is associated with lower longitudinal strain in the fibrotic wall segments. Speckle tracking can be used as a tool for the indirect evaluation of LE in FD.
    European Heart Journal 03/2013; · 10.48 Impact Factor
  • Article: Impact of regional left ventricular function on outcome for patients with Al amyloidosis.
    [show abstract] [hide abstract]
    ABSTRACT: The aim of this study was to explore the left ventricular (LV) deformation changes and the potential impact of deformation on outcome in patients with proven light-chain (AL) amyloidosis and LV hypertrophy. Cardiac involvement in AL amyloidosis patients is associated with poor outcome. Detecting regional cardiac function by advanced non-invasive techniques might be favorable for predicting outcome. LV longitudinal, circumferential and radial peak systolic strains (Ssys) were assessed by speckle tracking imaging (STI) in 44 biopsy-proven systemic AL amyloidosis patients with LV hypertrophy (CA) and in 30 normal controls. Patients were divided into compensated (n = 18) and decompensated (n = 26) group based on clinical assessment and followed-up for a median period of 345 days. Ejection fraction (EF) was preserved while longitudinal Ssys (LSsys) was significantly reduced in both compensated and decompensated groups. Survival was significantly reduced in decompensated group (35% vs. compensated 78%, P = 0.001). LSsys were similar in apical segments and significantly reduced in basal segments between two patient groups. LSsys at mid-segments were significantly reduced in all LV walls of decompensated group. Patients were further divided into 4 subgroups according to the presence or absence of reduced LSsys in no (normal), only basal (mild), basal and mid (intermediate) and all segments of the septum (severe). This staging revealed continuously worse prognosis in proportion to increasing number of segments with reduced LSsys (mortality: normal 14%, mild 27%, intermediate 67%, and severe 64%). Mid-septum LSsys<11% suggested a 4.8-fold mortality risk than mid-septum LSsys≥11%. Multivariate regression analysis showed NYHA class and mid-septum LSsys were independent predictors for survival. Reduced deformation at mid-septum is associated with worse prognosis in systemic amyloidosis patients with LV hypertrophy.
    PLoS ONE 01/2013; 8(3):e56923. · 4.09 Impact Factor
  • Article: Methods for Assessment of Left Ventricular Systolic Function in Technically Difficult Patients with Poor Imaging Quality.
    [show abstract] [hide abstract]
    ABSTRACT: The assessment of left ventricular (LV) systolic function is often the most important information obtained during clinical echocardiography. Although LV systolic function may be visually estimated in many patients with or without contrast opacification, technically difficult patients may require alternative methods for evaluating LV systolic function. In this review, the authors describe several surrogate echocardiographic methods that might be helpful for the evaluation of LV systolic function in patients with poor image quality, including endocardial border delineation by contrast agents, mitral annular plane systolic excursion, mitral annular velocity derived from tissue Doppler, systolic time intervals, mitral regurgitation-derived LV dP/dt, and estimation of cardiac output by Doppler echocardiography. After a short introduction to the various issues involved, the authors propose a method for suitable measurement. In addition, indications and clinical implications, as well as limitations, of the different methods are discussed.
    Journal of the American Society of Echocardiography: official publication of the American Society of Echocardiography 12/2012; · 2.98 Impact Factor
  • Article: Clinical implication of mitral annular plane systolic excursion for patients with cardiovascular disease.
    [show abstract] [hide abstract]
    ABSTRACT: Mitral annular plane systolic excursion (MAPSE) has been suggested as a parameter for left ventricular (LV) function. This review describes the current clinical application and potential implications of routinely using MAPSE in patients with various cardiovascular diseases. Reduced MAPSE reflects impaired longitudinal function and thus provides complementary information to ejection fraction (EF), which represents the global result of both longitudinal and circumferential contraction. Reduced long-axis deformation results from dysfunctional or stressed longitudinal myofibres due to endo- (and potentially epi-) cardial ischaemia, fibrosis, or increased wall stress. In patients with aortic stenosis, reduced MAPSE is suggestive of subendocardial fibrosis. Moreover, reduced MAPSE could be used as a sensitive early marker of LV systolic dysfunction in hypertensive patients with normal EF, where compensatory increased circumferential deformation might mask the reduced longitudinal deformation. In addition, reduced MAPSE was associated with poor prognosis in patients with heart failure, atrial fibrillation and post-myocardial infarction as well as in patients with severe aortic stenosis undergoing aortic valve replacement. Despite of the routine use of newer and more refined echocardiographic technologies nowadays, such as strain-rate imaging, speckle-tracking imaging, and 3D echocardiography, the use of MAPSE measurement is still especially helpful to evaluate LV systolic function in case of poor sonographic windows, since good imaging quality is required for most of the modern echocardiographic techniques with the exception of tissue Doppler imaging.
    European heart journal cardiovascular Imaging. 11/2012;
  • Article: Echocardiographic quantification of regional deformation helps to distinguish isolated left ventricular non-compaction from dilated cardiomyopathy.
    [show abstract] [hide abstract]
    ABSTRACT: Pronounced trabeculation is presented in both left ventricular non-compaction (LVNC) and dilated cardiomyopathy (DCM), which sometimes makes the differentiation difficult. We hypothesized that echocardiographic deformation analysis would help to differentiate these two cardiomyopathies. We investigated 15 patients with LVNC (9 males; 42 ± 9 years), 15 age- and gender-matched DCM patients, and 15 healthy controls. The echocardiographic diagnosis of LVNC was confirmed by magnetic resonance imaging. In all subjects standard echocardiography and tissue Doppler imaging (TDI) to study regional LV deformation were carried out. No statistical difference was observed in standard echocardiographic parameters between LVNC and DCM patients. Compared with controls, both patient groups showed significantly reduced annular displacements (septal: controls 14 ± 2 mm vs. DCM 6 ± 3 mm vs. LVNC 7 ± 3 mm) and reduced strain values of the LV segments. A characteristic deformation pattern with significantly higher values in the LV base compared with the apex was observed in patients with LVNC by deformation measurements with TDI. This gradient was found particularly in the lateral and inferior wall but spared the anteroseptal wall; non-compaction was not found in basal segments throughout the ventricle and also spared the anteroseptal midventricular wall. In DCM the strain and strain rate values were homogeneously reduced in all LV segments. A special regional deformation pattern (preserved deformation in basal segments of LVNC) seems to be of major diagnostic help for the definite differential diagnosis of LVNC and DCM.
    European Journal of Heart Failure 01/2012; 14(2):155-61. · 4.90 Impact Factor
  • Article: Failure to unmask pseudonormal diastolic function by a valsalva maneuver: tricuspid insufficiency is a major factor.
    [show abstract] [hide abstract]
    ABSTRACT: For the clinical assessment of patients with dyspnea, the inversion of the early (E) and late (A) transmitral flow during Valsalva maneuver (VM) frequently helps to distinguish pseudonormal from normal filling pattern. However, in an important number of patients, VM fails to reveal the change from dominant early mitral flow velocity toward larger late velocity. From December 2009 to October 2010, we selected consecutive patients with abnormal filling with (n=25) and without E/A inversion (n=25) during VM. Transmitral, tricuspid, and pulmonary Doppler traces were recorded and the degree of insufficiency was estimated. After evaluating all standard echocardiographic morphological, functional, and flow-related parameters, it became evident that the failure to unmask the pseudonormal filling pattern by VM was related to the degree of the tricuspid insufficiency (TI). TI was graded as mild in 24 of 25 patients in the group with E/A inversion during VM, whereas TI was graded as moderate to severe in 24 of the 25 patients with pseudonormal diastolic function without E/A inversion during VM. Our data suggest that TI is a major factor to prevent E/A inversion during a VM in patients with pseudonormal diastolic function. This probably is due to a decrease in TI resulting in an increase in forward flow rather than the expected decrease during the VM. Thus, whenever a pseudonormal diastolic filling pattern is suspected, the use of a VM is not an informative discriminator in the presence of moderate or severe TI.
    Circulation Cardiovascular Imaging 09/2011; 4(6):671-7. · 5.94 Impact Factor
  • Article: Echocardiographic evaluation of systolic and diastolic function in patients with cardiac amyloidosis.
    [show abstract] [hide abstract]
    ABSTRACT: The typical appearance of cardiac amyloidosis using standard echocardiographic techniques is usually a late finding only in patients with relatively advanced stages of the disease. Early noninvasive identification of cardiac amyloidosis is of growing clinical importance. Newer echocardiographic techniques, including tissue Doppler imaging and deformation imaging (strain rate imaging and 2-dimensional speckle tracking), are powerful tools for quantifying regional myocardial motion and deformation. Using these advanced techniques, early functional impairment in cardiac amyloidosis may be detectable when the results of standard echocardiography are still normal or inconclusive. This review provides a comprehensive overview of the different echocardiographic approaches for the assessment of systolic and diastolic function in patients with cardiac amyloidosis. Special attention is paid to regional myocardial function assessed by tissue Doppler imaging, strain rate imaging, and 2-dimensional speckle-tracking imaging.
    The American journal of cardiology 08/2011; 108(4):591-8. · 3.58 Impact Factor
  • Article: Tei index in fabry disease.
    [show abstract] [hide abstract]
    ABSTRACT: Systolic and diastolic dysfunction of the left ventricle are present in patients with cardiac involvement in Fabry disease. The aim of this study was to investigate the diagnostic value of the Tei index, a marker for combined diastolic and systolic function, in patients with Fabry disease. A total of 66 consecutive patients with genetically confirmed Fabry disease were included in this study. Standard echocardiography, including the Tei index, and magnetic resonance imaging were performed. Patients were followed for 2.9 ± 1.9 years; 56 patients received enzyme replacement therapy, and 10 patients had natural history follow-up. Patients were subdivided into three groups: (1) those without cardiac involvement, (2) those with left ventricular (LV) hypertrophy and without late enhancement on magnetic resonance imaging, and (3) those with late enhancement on magnetic resonance imaging. The Tei index was significantly higher in the groups 2 (0.56 ± 0.10) and 3 (0.60 ± 0.16) compared with patients without cardiac involvement (0.44 ± 0.10) (P < .001). All patients with Tei indexes > 0.64 showed signs of cardiomyopathy. In contrast, ejection fractions were normal in all three patient groups and therefore not useful for the detection of cardiac involvement. A significant positive correlation was observed between LV wall thickness and the Tei index in the complete patient cohort. Moreover, receiver operating characteristic analysis revealed a large area under the curve for Tei index and hypertrophy, while the area under the curve for fibrosis was small. The Tei index remained unchanged in the natural history and enzyme replacement therapy groups during follow-up. In this cohort, the Tei index was of limited value to detect myocardial fibrosis and monitor enzyme replacement therapy. However, the progression of cardiomyopathy toward LV hypertrophy seems to be paralleled by global functional impairment, which can be assessed by the Tei index but not by ejection fraction. Thus, the Tei index seems to be a global parameter that can detect LV functional reduction in patients with Fabry disease.
    Journal of the American Society of Echocardiography: official publication of the American Society of Echocardiography 06/2011; 24(9):1026-32. · 2.98 Impact Factor
  • Article: Prominent papillary muscles in Fabry disease: a diagnostic marker?
    [show abstract] [hide abstract]
    ABSTRACT: Fabry disease is often linked with a prominent papillary muscle. It remains unknown whether this sign could be used as a diagnostic marker to screen for Fabry patients. Standard echo was performed in 101 consecutive patients with concentric left ventricular (LV) hypertrophy (28 Fabry, 30 Friedreich, 34 isolated arterial hypertension, 9 amyloidosis) and 50 healthy controls. In addition, the areas of both papillary muscles, as well as the LV endocardial circumference, were manually traced in short axis views. A ratio of papillary muscle size to LV circumference was calculated (PM_LV_ratio). The papillary muscle area was positively correlated to LV wall thickness in this cohort (p < 0.0001; r = 0.58). In all patient subgroups, the absolute papillary muscle area was significantly enlarged and the PM_LV_ratio was significantly higher when compared with controls. However, Fabry patients showed a significantly larger absolute papillary muscle area than Friedreich and amyloidosis patients and a higher PM_LV_ratio than hypertensive and amyloidosis patients. Enlarged absolute papillary muscle area was evidenced in 21 (75%), and increased PM_LV_ratio was found in 22 (78%) of 28 Fabry patients. Combining these two parameters yields a sensitivity of 75% and specificity of 86% for diagnosing Fabry disease with LV hypertrophy. Only 10 of 73 non-Fabry patients (14%) (4 Friedreich, 1 amyloidosis, 5 hypertensive) showed an increased absolute papillary muscle area and PM_LV_ratio. In conclusion, this study confirmed the assumption that the prominent papillary muscle could be an echocardiographic marker for detection of Fabry patients with concentric LV hypertrophy.
    Ultrasound in medicine & biology 11/2010; 37(1):37-43. · 2.02 Impact Factor