Mitral valve coaptation and its relationship to late diastolic flow: A color Doppler and vector flow map echocardiographic study in normal subjects

Vector flow mapping analysis of left ventricular vortex performance in type 2 diabetic patients with early chronic kidney disease

BACKGROUND

Diabetes is the leading cause of chronic kidney disease (CKD) and contributes to an elevated incidence of diastolic dysfunction in the early stages of CKD. Intracardiac vortex is a novel hemodynamic index for perceiving cardiac status. Here, we visualized left ventricular (LV) vortex characteristics using vector flow mapping (VFM) in type 2 diabetic patients with early CKD.

METHODS

This cross-sectional study included 67 controls and 89 type 2 diabetic patients with stages 2-3a CKD. All subjects underwent transthoracic echocardiographic examination. LV anterior vortex during early diastole (E-vortex), atrial contraction (A-vortex) and systole (S-vortex) were assessed using VFM in the apical long-axis view. Its relation to glycemia or LV filling echocardiographic parameters were further analyzed using correlation analysis.

RESULTS

Type 2 diabetic patients with early CKD had a small area (439.94 ± 132.37 mm2 vs. 381.66 ± 136.85 mm2, P = 0.008) and weak circulation (0.0226 ± 0.0079 m2/s vs. 0.0195 ± 0.0070 m2/s, P = 0.013) of E-vortex, but a large area (281.52 ± 137.27 mm2 vs. 514.83 ± 160.33 mm2, P ˂ 0.001) and intense circulation (0.0149 ± 0.0069 m2/s vs. 0.0250 ± 0.0067 m2/s, P < 0.001) of A-vortex compared to controls. CKD patients with poorly controlled hyperglycemia had stronger A-vortex (area: 479.06 ± 146.78 mm2 vs. 559.96 ± 159.27 mm2, P = 0.015; circulation: 0.0221 ± 0.0058 m2/s vs. 0.0275 ± 0.0064 m2/s, P < 0.001) and S-vortex (area: 524.21 ± 165.52 mm2 vs. 607.87 ± 185.33 mm2, P = 0.029; circulation: 0.0174 ± 0.0072 m2/s vs. 0.0213 ± 0.0074 m2/s, P = 0.015), and a longer relative duration of S-vortex (0.7436 ± 0.0772 vs. 0.7845 ± 0.0752, P = 0.013) than those who had well-controlled hyperglycemia. Glycemia, and E/A (a LV filling parameter) were respectively found to had close correlation to the features of A-vortex and S-vortex (all P < 0.05).

CONCLUSIONS

Abnormal LV vortices were detected in type 2 diabetic patients with early CKD using VFM, especially in those who neglected hyperglycemic control. LV vortex might be a promising parameter to slow or halt the hyperglycemia-induced diastolic dysfunction in early CKD.

Intraventricular Vector Flow Imaging with Blood Speckle Tracking in Adults: Feasibility, Normal Physiology and Mechanisms in Healthy Volunteers

This study examines the feasibility of blood speckle tracking for vector flow imaging in healthy adults and describes the physiologic flow pattern and vortex formation in relation to the wall motion in the left ventricle. The study included 21 healthy volunteers and quantified and visualized flow patterns with high temporal resolution down to a depth of 10-12 cm without the use of contrast agents. Intraventricular flow seems to originate during the isovolumetric relaxation with a propagation of blood from base to apex. With the E-wave, rapid inflow and vortex formation occurred on both sides of the valve basally. During diastasis the flow gathers in a large vortex before the pattern from the E-wave repeats during the A-wave. In isovolumetric contraction, the flow again gathers in a large vortex that seems to facilitate the flow out in the aorta during systole. No signs of a persistent systolic vortex were visualized. The geometry of the left ventricle and the movement of the AV-plane is important in creating vortices that are favorable for the blood flow and facilitate outflow. The quantitative measurements are in concordance with these findings, but the clinical interpretation must be evaluated in future clinical studies.

Age-Related Changes in Left Ventricular Vortex Formation and Flow Energetics

Analysis of the cardiac vortex has been used for a deeper understanding of the pathophysiology in heart diseases. However, physiological changes of the cardiac vortex with normal aging are incompletely defined. Vector flow mapping (VFM) is a novel echocardiographic technique based on Doppler and speckle tracking for analysis of the cardiac vortex. Transthoracic echocardiography and VFM analysis were performed in 100 healthy adults (33 men; age = 18–67 years). The intracardiac flow was assessed throughout the cardiac cycle. The size (cross-sectional area) and circulation (equivalent to the integral of normal component of vorticity) of the largest vortices in systole (S-vortex), early diastole (E-vortex), and late diastole (A-vortex) were measured. Peak energy loss (EL) was calculated from information of the velocity vector of intracardiac flow in systole and diastole. With normal aging, the circulation (p = 0.049) of the E-vortex decreased, while that of the A-vortex increased (both p < 0.001). E-vortex circulation correlated directly to e’ (p = 0.003), A-vortex circulation correlated directly to A and a’ (both p < 0.001), and S-vortex circulation correlated directly to s’ (p = 0.032). Despite changes in vortex patterns, energy loss was not significantly different in older individuals. Normal aging is associated with altered intracardiac vortex patterns throughout the cardiac cycle, with the late-diastolic A-vortex becoming physiologically more dominant. Maintained energy efficiency accompanies changes in vortex patterns in aging hearts.

Factors contributing to energy loss in left ventricle during diastolic and systolic phases in elderly patients

BACKGROUND

The change of left ventricular function deteriorated with age because of gradual increases of blood pressure may result in increased energy loss (EL) in left ventricle (LV). The present study investigated EL in LV among hypertensive elderly patients and examined factors contributing to EL.

METHODS

A single-center retrospective study was performed on elderly hypertensive outpatients (≥65 years) who underwent echocardiography (N = 105). EL in the LV was measured using a vector flow mapping system, and factors affecting peak EL during the early-diastolic phase (ED-EL), late-diastolic phase (LD-EL), and systolic phase (Sys-EL) were evaluated.

RESULT

Mean age was 79.9 ± 6.4 years (male 43%). Mean ED-EL, LD-EL, and Sys-EL were 42.1 ± 46.7, 75.6 ± 60.2, and 40.4 ± 40.2 mJ/N/s. In a stepwise regression analysis, the E/e'(lateral) (unstandardized B = 0.005, 95%CI -0.03 to 0.007, standardized β = 0.434, P < .001) was identified as factors affecting ED-EL. The factors affecting LD-EL were E/A ratio (B = -0.122, 95%CI -0.176 to -0.068, β = -0.470, P < .001) and time velocity integral (TVI) in LVOT (unstandardized B = 0.002, 95%CI 0.000 to 0.004, β = 0.247, P = .021). The factors influencing Sys-EL were TVI in LVOT (B = 0.002, 95%CI 0.001 to 0.004, β = 0.390, P < .001), E/A ratio (B = -0.054, 95%CI -0.093 to -0.015, β = -0.258, P = .008), left ventricular outflow tract (LVOT) diameter (B = -0.006, 95%CI -0.010 to -0.002, β = -0.307, P = .006), and left ventricular mass index (B = 0.000, 95%CI 0.000 to 0.001, β = 0.208, P = .039).

CONCLUSION

Peak EL in the LV was higher during diastolic phase than systolic phase among elderly hypertensive patients. Peak EL both during late-diastolic phase and systolic phase was affected by systolic blood flow in LVOT and LV transmitral flow pattern.

Relationship between left ventricular isovolumic relaxation flow patterns and mitral inflow patterns studied by using vector flow mapping

The purpose of this study was to investigate the relationship between isovolumic relaxation flow (IRF) patterns in left ventricle (LV) and mitral inflow patterns. Color Doppler loops were acquired for vector flow mapping in apical long-axis view in 57 patients with coronary artery disease, 31 patients with dilated cardiomyopathy, and 58 healthy controls. IRF patterns were classified into three categories: pattern A, apically directed flow; pattern B, bidirectional flow with small scattered vortices; and pattern C, a large vortex. All normals and patients with normal LV filling (n = 10) showed pattern A. Patients with impaired relaxation consisted of 31 (66%) patients having pattern A, 11 (23%) having pattern B, and 5 (11%) having pattern C. Patients with pseudonormal filling included 4 (31%) patients having pattern A, 7 (54%) having pattern B, and 2 (15%) having pattern C. In patients with restrictive filling, 14 (78%) showed pattern C, 4 (22%) showed pattern B, and no patient showed pattern A. IRF patterns were associated with LV filling patterns (χ² = 52.026, p < 0.001). There are significant relationships between LV filling and IRF patterns. IRF patterns may provide an index for evaluation of LV diastolic function.

Relationship between left ventricular vortex and preejectional flow velocity during isovolumic contraction studied by using vector flow mapping

OBJECTIVES

The purpose of this study was to investigate the relationship between the vortex in left ventricle (LV) during the isovolumic contraction (IVC) period and the preejectional flow velocity in LV outflow tract (V_LVOT ).

METHODS

Color Doppler loops were acquired for vector flow mapping in apical long-axis view in 76 patients with dilated cardiomyopathy, 61 patients with coronary artery disease and 36 healthy controls.

RESULTS

All normals exhibited an IVC vortex reaching the LV base. V_LVOT was significantly related to IVC vortex area flux, transmitral A velocity, mitral annular a' velocity and E/e' ratio, respectively. Transmitral A velocity was the only independent predictor of V_LVOT (R²  = 0.292, P = 0.001). In patients the IVC vortex could reach the LV base, middle, or apex. V_LVOT was significantly related to range, area and area flux of the IVC vortex, LV size, LVEF, mitral annular velocities, E/e' ratio, transmitral A velocity, and IVC time, respectively. Range and corrected area flux of the IVC vortex, LV end-systolic short diameter, and IVC time were independent predictors of V_LVOT (R²  = 0.608, P < 0.001).

CONCLUSIONS

In normals, the transmitral A velocity (momentum) is efficiently transferred from mitral orifice to LV outflow tract by a normally formed IVC vortex, and transmitral A velocity is the only independent predictor of V_LVOT . However, in patients with a wide range of LV enlargement and dysfunction, the momentum transfer is associated with not only the LV dimension and function, but also the range and volume of the IVC vortex.