| Background and Aims:BackgroundCardiovascular disease is the most important risk factor of death in diabetic patients. Impaired glucose metabolism might be ignored for years until severe cardiovascular complications occurred. Previous studies have showed that left ventricular deformation was decreased in patients with impaired glucose metabolism. Blood flow dynamics was influenced by the valves, geometry of chambers, and wall motion. They adapted to maintain a stable hemodynamic environment in normal or pathological conditions. Thus, we presumed that the blood flow dynamics of patients with impaired glucose metabolism would change because of the impaired left ventricular deformation.Aims1. To analyze the blood flow dynamics and energy loss with vector flow mapping VFM in patients with prediabetes and type 2 diabetes;2. To analyze the left ventricular mechanical deformation and its relationship with energy loss with VFM and two-dimensional speckle tracking echocardiography (STE) in patients with impaired glucose metabolism.Materials and Methods:1. Study population and groupingThis cross-sectional study included 30 normotensive prediabetes patients,51 recently diagnosed patients with diabetes and 38 healthy controls of similar sex and age distributions.2. Methods2.1 General information and serum index To measure the body weight (kg), height (m), blood pressure (mmHg); glucose (mmol/L), total cholesterol (mmol/L), triglycerides (mmol/L), high-density lipoprotein (mmol/L), and low-density lipoprotein levels (mmol/L).2.2 Two-dimensional transthoracic echocardiography and index(1) Two-dimensional echocardiography:the diameter of left atrium (LA, mm), left ventricle (LV, mm), left ventricle posterior wall (LVPW, mm), interventricular septum (IVS, mm), ejection fraction (EF,%);(2) Pulse Doppler echocardiography:transmitral valve blood flow E (m/s) and A (m/s), deceleration time (DT, ms), isovolumic relaxation time (FVRT, ms), e’(m/s), a’(m/s), s’(m/s), and transmitral valve blood flow propagation velocity (Vp, m/s).2.3 STE and indexTo analyze the left ventricular mechanical deformation with STE in apical four chamber and two chamber view.(1) Longitudinal strain (%) and strain rate (s-1);(2) Circumferential strain (%) and strain rate (s-1);(3) Radial strain (%) and strain rate (s-1);(4) Peak torsion (°), systolic twist (°/s), and diastolic untwist (°/s).2.4 VFM and indexVFM was based on apical long-axis image and EL was calculated frame by frame. Calculate the energy loss in the whole left ventricle, the base, the middle, and apex during isovolumic contraction (IVC), rapid ejection (RE), slow ejection (SE), isovolumic relaxation (IVR), rapid filling (RF), slow filling (SF), and atrial contraction (AC).3. Statistical analysisData were analyzed using SPSS version 19.0. Continuous variables are presented as the mean±standard deviation (SD) values as they showed normal distributions. Differences between categorical variables were analyzed using the χ2 test. To compare changes in EL (controls, pre-DMs, and DMs) over time, we performed analysis of variance (ANOVA) with repeated measurement followed by a post hoc comparison using the Bonferroni test. Correlations between two parameters were analyzed using Pearson correlation tests. Stepwise multiple regression analyses were used to study the independent factors correlating with EL. Reproducibility was assessed using the Bland-Altman analysis. P values<0.05 were considered statistically significant.Results:1. General information and serum indexAge, sex, heart rate, blood pressure didn’t show much difference (P> 0.05).Total cholesterol, triglycerides, and low-density lipoprotein were gradually increased from controls to pre-DMs and DMs, difference between DM and controls was significant (P< 0.05). While high-density lipoprotein was highest in controls (P< 0.05).2. Two-dimensional transthoracic echocardiography and doppler echocardiography(1) Two-dimensional echocardiography:LV, IVS, LVPW, and EFwere not significantly different in the three groups (P> 0.05). While LAwas significantly higher in DMs (P< 0.05).(2) Pulse Doppler echocardiography:E, and e’were not significantly different in the three groups (P> 0.05). While A, E/e’, DT, and IVRT were significantly higher in DMs (P< 0.05). E/A and e’were lower in DMs than the other two groups (P< 0.05). e’/a’was only significantly different between DMs and controls (P< 0.05). E/Vp of controls was significantly lower than the other two groups (P< 0.05).3. Left ventricular mechanical deformation with STE(1) Systole:longitudinal strain and circumferencial strain rate of DMs were significantly lower than that in pre-DM and controls (P<0.05). Longitudinal strain rate, radial strain and strain rate, peak torsion of pre-DM and DM were lower than that in controls (P<0.05).(2) Early diastole:longitudinal strain rate, radial strain rate, circumferential stain rate and diastolic untwisting velocity of DMs were lower than that in controls (P<0.05).(3) Atrial contraction:the radial strain rate of DM and pre-DM were lower than controls (P<0.05).4. Left ventricular energy loss and vortex with VFMEL gradually decreased from the base to the middle and apex in the controls. EL-apex of DM patients was higher than EL-mid during IVR. EL-total, EL-base, EL-mid, and EL-apex changed over time (all P< 0.05). Both EL-total and EL-base were increased at RE, RF, and AC compared with other phases. E-mid reached its climax at RF, and EL-apex reached its climax at RF and AC (P< 0.05).Compared with controls, EL-total was increased in pre-DM and DM patients during SE, IVR, RF, and SF (P< 0.05). EL-base was increased during SE, IVR, and SF (P< 0.05). EL-mid was increased during RE, SE, and SF (P< 0.05). By contrast, EL-apex was only increased at SF{P< 0.05).Vortex circulation during different phases was mildly increased from controls to prediabetes and diabetes, whereas vortex area was decreased. Significant differences were observed for vortex circulation during atrial contraction between controls and the other two groups (P< 0.01). During diastole, we even observed more than three vortices in some instances. Small vortices during IVR also appeared more frequently in pre-DM and DM patients compared with controls (P< 0.05).5. Correlation and multiple regression analysesCorrelation analysis showed that transmitral valve blood flow velocity, LV mechanical deformation, vortex circulation and area were correlated with LV energy loss during different phases.Stepwise multiple regression analysis:(1) LV EL-total during systole (LVELs):independently associated with the peak torsion (β =-0.191, P= 0.029), and circulation (p= 0.357, P< 0.01);(2) LV EL-total during early diastole (LVELed):independently associated with transmitral valve blood flow velocity E (fi= 0.348, P< 0.01), peak torsion (β=-0.210, P= 0.003), and circulation (β= 0.504, P< 0.01);(3) LV EL-total during atrial contraction (LVELac):independently associated with transmitral valve blood flow velocity A (β= 0.353, P< 0.01), E/A (β=-0.129, P= 0.049), peak diastolic untwisting velocity (β=-0.232, P= 0.001), circulation (β= 0.423, P< 0.01), and vortex area (β=-0.372, P< 0.01).Conclusions:1. LVEL assessed by VFM was higher during some phases of diastole and SE in patients with pre-DM and DM compared with controls.2. Traditional echocardiographic indexes didn’t show much significant differenc between patients with impaired glucose metabolism and controls, whicl LV mechanical deformation was decreased in patient with impaired glucose metabolism in various degrees.3. The changes of blood flow dynamics and myocardial mechanics were both correlated with EL independently.Background and Aims:BackgroundPrevious studies found that left ventricle (LV) diastolic dysfunction was the first detectable pathophysiology, and LV diastolic dysfunction has been found in pre-diabetic patients. Optimized left atrial-left ventricular coupling is important for the efficiency of cardiovascular system. Decreased left atrial reservoir function and increased bumping is the first sign of diastolic dysfunction. Thus, assessment of left atrial function and left atrial-left ventricular coupling is the key to early detect the cardiac dysfunction of patients with impaired glucose metabolism. While there is no clinical research to explore the left atrial-left ventricular coupling in patients with impaired glucose metabolism.Another important complication of diabetes is the vascular disease. Increased arterial stiffness would occur at any age in patients with diabetes or metabolism syndrome. In children with those diseases, arterial stiffness appeared earlier. The interaction between heart and vascular, also known as ventricular-arterial coupling could increase cardiac output, adjust blood pressure, heart rate, and preload to maintain the body within normal range. In patients with impaired glucose metabolism, the afterload of LV increases as the arterial stiffness increases. According to Frank-Starling mechanism, LV increases its bump function as compensation, as a result, LV stiffness increased too. In addition, vascular stiffness increases, the velocity of the pulse wave increases, reflection time thus decreases, which would aggravate the afterload of LV during systole. Many studies used the noninvasive methods to evaluate the ventricular-arterial coupling in patients with hypertension, which is simple, effective, and has a good correlation with catheter calculation. But how’s the ventricular-arterial coupling in patients with impaired glucose metabolism is unknown.Vector flow mapping (VFM) could demonstrate the blood flow distribution after the coding of blood flow vector. Energy loss (EL), derived from VFM, reflects the flow dispersion in space, which is assumed as an index of the effectiveness of flow transfer. It also reflects the excessive afterload caused by turbulence. We can hypothesize that the blood flow field condition would change after the change of left atrial-left ventricular-arterial coupling.Aims1. To evaluate the function of left atrium in patients with impaired glucose metabolism with VFM and speckle tracking echocardiography (STE);2. To evaluate left atrial-left ventricular coupling in patients with impaired glucose metabolism with VFM and STE;3. To evaluate the arterial biomechanics in patients with impaired glucose metabolism noninvasively;4. To evaluate left ventricular-arterial coupling in patients with impaired glucose metabolism with VFM and STE.Materials and methods:1. Study population and groupingThis cross-sectional study included 29 normotensive patients with pre-diabetes (pre-DM),47 recently diagnosed patients with diabetes (DM), and 38 healthy controls of similar sex and age distributions.2. Methods2.1 General information and serum indexBody weight (kg), height (m), blood pressure (mmHg), glucose (mmol/L), total cholesterol (mmol/L), triglycerides (mmol/L), high-density lipoprotein (mmol/L), and low-density lipoprotein levels (mmol/L).2.2 Two-dimensional transthoracic echocardiography (TTE)TTE was performed at the ProSound F75 machine (Hitachi Aloka Medical Ltd., Tokyo, Japan), probe UST-52105 (1-5MHz).(1) LV index:left ventricular end-diastolic diameter (LVEDD, mm), left ventricular posterior wall (LVPW, mm), interventricular septum (IVS, mm), and ejection fraction (EF,%).(2) LA index:total left atrial stroke volume (LASVt, ml), passive left atrial stroke volume (LASVp, ml), active left atrial stroke volume (LASVa, ml), passive left atrial ejection fraction (LAPEF,%), total left atrial ejection fraction (LATEF,%), active left atrial ejection fraction (LAAEF,%).(3) Doppler index:transmitral valve blood flow E (m/s), A (m/s), decelaration time (DT, ms), isovolumic relaxation time (FVRT, ms), mitral valve annulus movement s’(m/s), e’(m/s), and a’(m/s).2.3 Left ventricular-arterial couplingArterial biomechanics was performed with ProSound F75 (Hitachi Aloka Medical Ltd., Tokyo, Japan), probe UST-5411 (10-13MHz).Arterial lastance (Ea, mmHg/ml), LV end-systolic elastance index (Ees), ventricular-vascular index (VVI), and arterial stiffness β were measured.2.4 STE analyze and indexesSTE was analyzed with commercial available software DAS-RS1 (Hitachi Aloka Medical Ltd., Tokyo, Japan).(1) LV mechanical deformation: longitudinal strain during systole, early diastole, and atrial contraction (%); circumferential strain during systole, early diastole, and atrial contraction (%); radial strain during systole, early diastole, and atrial contraction (%); longitudinal strain rate during systole, early diastole, and atrial contraction (s-1); circumferential strain rate during systole, early diastole, and atrial contraction (s-1); radial strain rate during systole, early diastole, and atrial contraction (s-1); peak torsion (°), systolic twisting velocity (°/s), and diastolic untwisting velocity (°/s).(2) LA mechanical deformation: LA strain during systole, early diastole, and atrial contraction (%), LA strain rate during systole, early diastole, and atrial contraction (s-1).2.5 VFM analyze and indexesLA and LV two-dimensional color Doppler flow images were analyzed with commercial available software DAS-RSI (Hitachi Aloka Medical Ltd., Tokyo, Japan).VFM index:LV energy loss during systole (LVELs, N/(m-s)), LV energy loss during early diastole (LVELed, N/(m·)), LV energy loss during atrial contraction (LVELac, N/(m-s)), LA energy loss during systole (LAELs, N/(m-s)), LA energy loss during early diastole (LAELed, N/(m-s)), LA energy loss during atrial contraction (LAELac, N/(m-s)).3. Reproducibility testIntra-and inter-observer variability of LAEL during different phases were analyzed.4. Statistic analysisData were analyzed using SPSS version 19.0. Continuous variables are presented as the mean ±standard deviation (SD) values as they showed normal distributions. Differences between categorical variables were analyzed using the χ2 test. Difference among the three groups was analyzed with ANOVA test, Post Hoc was usd LSD. Correlation between two variables was analyzed with Pearson correlation, the independent factor of LAEL was used stepwise multiple regression test. Bland-Altman analysis was used to test the reproducibility. P< 0.05 was considered as significant.Results:1. General information and serum indexAge, sex, heart rate, blood pressure didn’t show much difference (P> 0.05).The glucose of DM was higher than that in controls (P< 0.05), while the difference between pre-DM and controls was not significant (P> 0.05). Total cholesterol, triglycerides, and low-density lipoprotein were gradually increased from controls to pre-DMs and DMs (P < 0.05). While high-density lipoprotein was highest in controls (P< 0.05).2. Two-dimensional transthoracic echocardiography (TTE) and Doppler echocardiography2.1 LV index(1) TTE:LVEDD, IVS, LVPW, and EF were not significantly different (P> 0.05). While LA of DM was higher than that in controls and pre-DM (P< 0.05).(2) Doppler echocardiography:E and a’were not significantly different (P> 0.05). While A, E/e’, DT, and IVRT of DM were higher than that in pre-DM and controls (P< 0.05). E/A and e’of DM were lower than the other two groups (P< 0.05). e’/a’was only significant between controls and DM (P< 0.05).2.2 LA indexLA volume indexes and functional indexes were not significantly different except LASVa (P> 0.05, table 2). LASVa of DM was significantly higher than controls (P< 0.05). 3. LA and LV mechanical deformation3.1 LA mechanical deformation(1) Systole:SLAs of pre-DM and DM were higher than controls (P< 0.05). SRLAs of DM was higher than controls (P< 0.05).(2) Early diastole:SLAed and SRLAed of DM were higher than controls and pre-DM (P < 0.01). There is no difference between controls and pre-DM (P> 0.05).(3) Atrial contraction:SLAac and SRLAac were not significantly different (P> 0.05).(4) E/e’/SLAs:surrogate of LA stiffness, was higher in DM (P< 0.05).3.2 LV mechanical deformation(1) Systole:longitudinal strain, circumferential strain rate were higher in DM (P< 0.05). Longitudinal strain rate, radial strain and strain rate, peak torsion were higher in DM and pre-DM.(2) Early diastole:longitudinal strain rate, radial strain rate, circumferential strain rate, and diastolic untwisting velocity were higher in DM (P< 0.05).(3) Atrial contraction:radial strain rate was higher in DM and pre-DM (P< 0.05). 4. LA and LV energy loss4.1 LA energy loss(1) Systole:LAELs was not significantly different (P> 0.05).(2) Early diastole:LAELed of pre-DM and DM were higher (P< 0.05).(3) Atrial contraction:LAELac of DM was higher than that in pre-DM and controls (P< 0.05).4.2 LV energy loss(1) Systole:LVELs of DM was higher than controls (P< 0.05).(2) Early diastole:LVELed of DM was significantly higher than controls (P< 0.05).(3) Atrial contraction:LVELac of DM was higher than controls and pre-DM (P< 0.05). 5. LA-LV couplingEarly diastole:(1) Controls:LAELed was independently associated with LVELed (0=0.716, P<0.01);(2) Pre-DM:LAELed was independently associated with E (β=0.098, P=0.035), and LVELed 09=0.944, P<0.01);(3) DM:LAELed was independently associated with E (β=0.287, P=0.014), and LVELed 09=0.632,P<0.01).Atrial contraction:(1) controls:LAELac was independently associated with diastolic untwisting velocity (β=-0.277, P=0.039), and LVELac 09=0.553, P<0.01);(2) Pre-DM:LAELac was independently associated with SLAs (β=-0.263, P=0.046), and LVELac 09=0.668,P<0.01);(3) DM:LAELac was independently associated with peak torsion 09=-0.132, P=0.043), SLAs 05=-0.154, P=0.023), and LVELac (β=0.776, P<0.01).6. LV-arterial coupling6.1 LV-arterial coupling index Ees:not significantly different in the three groups (P> 0.05); β:β of DM was higher than controls and pre-DM (P< 0.05); Ea:Ea of DM was higher than controls (P< 0.05). VVI:VVI of DM was significantly higher than controls (P< 0.05); there’s no difference between pre-DM and controls (P> 0.05)6.2 LV-arterial coupling(1) LVELs was correlated with LV mechanical deformation (systolic longitudinal strain rate), Ees, and Ea (table 9, figure 7).(2) VVI was correlated with blood pressure, LV mechanical deformation (systolic longitudinal strain), and arterial stiffness p (table 10, figure 8). 7. ReproducibilityBland-Altman analysis showed that LAEL during different phases have good reproducibility.Conclusions:1. LA function as a reservoir and conduit decreased, while the bump function increased as compensation in patients with impaired glucose metabolism;2. LA blood flow dynamics and mechanical deformation was impaired in patients with impaired glucose metabolism, and they correlated with each other which resulted in abnormal LA-LV coupling;3. Arterial stiffness increased in diabetes, and the LV-arterial coupling was impaired;... |
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