Left ventricular twist and ventricular-arterial coupling in hypertensive patients

The Relationship of Renal Augmented Velocity Index With Ventricular-Arterial Coupling in Comparison to Renal Resistive Index: Analysis by Means of Arterial and Ventricular Elastances in Hypertensive Patients

OBJECTIVE

It's a well-known scientific statement that the heart and kidney functions are frequently tied together and the impairment of one directly alters the other. However, there exist knowledge gaps about this intricate pathophysiologic link and the exact unifying mechanism is not established. Herein, we aimed to investigate the presence of cardiorenal interaction at subclinical level while the conventional cardiac and renal clinical parameters are not disrupted yet in patients with hypertension.

METHODS

We chose a novel renal Doppler ultrasonographic parameter-augmented velocity index (Avi)-and an echocardiographic measure-ventriculoarterial coupling-which is complex to analyze but increasingly used after its acceptance about being a key determinant of cardiovascular efficiency. We recruited 137 patients without a previous history of antihypertensive medication use (47.4% women; median age, 49 years). Renal Avi, renal resistive index (RI), arterial elastance (Ea ), ventricular elastance (Ees ) and Ea /Ees (ventriculoarterial coupling) parameters were all examined.

RESULTS

Renal Avi, Ea , and Ea /Ees values were higher in females. Correlation analysis revealed that renal Avi was correlated with many hemodynamic variables including Ea and Ea /Ees . On multiple linear regression analysis, Ea and Ea /Ees remained as significant independent predictors of renal Avi but not of renal RI after adjustments for co-variables (β = 0.488, P < .001 for Ea ; β = 0.380, P < .001 for Ea /Ees ).

CONCLUSIONS

In comparison to renal RI, we suggest that renal Avi is a more reliable and promising index that can even measure subclinical changes in the cardiorenal circulation which needs to be elucidated.

Phenotyping the hypertensive heart

Arterial hypertension remains the most frequent cardiovascular (CV) risk factor, and is responsible for a huge global burden of disease. Echocardiography is the first-line imaging method for the evaluation of cardiac damage in hypertensive patients and novel techniques, such as 2D and D speckle tracking and myocardial work, provide insight in subclinical left ventricular (LV) impairment that would not be possible to detect with conventional echocardiography. The structural, functional, and mechanical cardiac remodelling that are detected with imaging are intermediate stages in the genesis of CV events, and initiation or intensification of antihypertensive therapy in response to these findings may prevent or delay progressive remodelling and CV events. However, LV remodelling—especially LV hypertrophy—is not specific to hypertensive heart disease (HHD) and there are circumstances when other causes of hypertrophy such as athlete heart, aortic stenosis, or different cardiomyopathies need exclusion. Tissue characterization obtained by LV strain, cardiac magnetic resonance, or computed tomography might significantly help in the distinction of different LV phenotypes, as well as being sensitive to subclinical disease. Selective use of multimodality imaging may therefore improve the detection of HHD and guide treatment to avoid disease progression. The current review summarizes the advanced imaging tests that provide morphological and functional data about the hypertensive cardiac injury.

Two-dimensional speckle tracking to image ventricular-arterial coupling in uremia

Objective

To study ventricular‐arterial coupling(VAC) in uremic patients by application of two‐dimensional speckle tracing imaging (2DSTI).

Methods

One hundred uremic patients were divided into two groups based on left ventricular ejection fraction (LVEF): group 1 with LVEF ≥ 5%, and group 2 with LVEF < 55%. Forty healthy subjects were recruited as a control group. Conventional echocardiography was performed; VAC components and myocardial performance index were calculated. Longitudinal strain (LS) of 17 segments was measured using 2DSTI. Mean base (LS_BA), papillary muscle (LS_PM), and apex values (LS_AP) were calculated.

Results

Compared to subjects in the control group and group 1, subjects in group 2 exhibited decreased LV end‐diastolic volume (EDV), end‐systolic volume (ESV), LV mass index (LVMI), and VAC (P < 0.05). EF, fractional shortening (FS), end‐systolic elastance (Ees) were significantly higher in group 2 (P < 0.05). SL_BA, SL_PM, and SL_AP differed significantly among the groups (all P < 0.05). SL_BA, SL_PM, and SL_AP correlated positively with Ees, EF, and FS (all P < 0.05) but negatively with arterial elastance (Ea), VAC, systemic vascular resistance index (SVRI), and rate‐pressure product (RPP) (all P < 0.05). Multiple regression analysis revealed that relative wall thickness (RWT), LVMI, LS_AP, and stroke works (SW) were independent predictors of VAC (b′ = −0.443, 0.537, −0.470, and −0.491, all P < 0.05).

Conclusions

In patients with uremia, LV myocardial LS gradually decreased as LV systolic dysfunction decreased. VAC correlated negatively with left ventricular LS, and LS_AP was an independent predictor for VAC.

Relation of arterial stiffness to left ventricular structure and function in healthy women

BACKGROUND

Interactions between the left ventricular (LV) and the arterial system, (ventricular-arterial coupling) are key determinants of cardiovascular function. However, most of studies covered multiple cardiovascular risk factors, which also contributed to the morphological and functional changes of LV. The aim of this study was to examine the relationship between arterial stiffness and LV structure and function in healthy women with a low burden of risk factors.

METHODS

Healthy women from the Twins UK cohort (n = 147, mean age was 54.07 ± 11.90 years) were studied. Arterial stiffness was evaluated by carotid-femoral pulse wave velocity (cf-PWV). LV structure and function were assessed by two-dimensional speckle tracking echocardiography.

RESULTS

cf-PWV was significantly associated with most measures of LV geometry and function, including relative wall thickness (RWT), E/e' ratio, global circumferential and radial strain, apical rotation and LV twist (each p <  0.05), but bore no relation to global longitudinal strain. After adjustment for age, body mass index, blood pressure and heart rate, cf-PWV was significantly correlated with RWT, global circumferential strain, apical rotation and LV twist (β = 0.011, - 0.484, 1.167 and 1.089, respectively, each p ≤  0.05).

CONCLUSIONS

In healthy women with a low burden of risk factors, elevated arterial stiffness was intimately interwoven with increased LV twisting even before LV dysfunction becomes clinically evident.

Left Ventricular Torsion Associated With Aortic Stiffness in Hypertension

BACKGROUND

Left ventricular (LV) torsion plays a key role in cardiac efficiency. In hypertension, aortic stiffening augments cardiac afterload. However, little is known about the links between LV regional contraction and aortic stiffness. We, therefore, investigated these relationships and their contribution to LV diastolic function.

METHODS AND RESULTS

The study included normotensive and hypertensive individuals with normal LV ejection. Apical, basal, and global LV rotation rate and LV global longitudinal strain were measured (2-dimensional speckle tracking echocardiography). Aortic stiffness was calculated from carotid-femoral pulse wave velocity, and LV relaxation was calculated from early diastolic mitral annulus motion. The ratio of basal or apical untwist/twist rates was calculated to assess relationships between aortic stiffness and LV torsion parameters. LV twist and untwist rates were greater in hypertensive than normotensive individuals because of increased basal twist (P<0.001) and untwist (P<0.001) rates. LV relaxation was reduced (early diastolic mitral annulus motion=7.4±1.9 versus 10.4±2.3 cm/s; P<0.001). In the whole population, basal untwist rate increased with aortic stiffening (R=0.43; P<0.001) and LV relaxation (R=0.41; P=0.001). The ratio of basal untwist/twist rate was positively correlated with carotid-femoral pulse wave velocity, and in the hypertensive group, was greater than in the control group and positively correlated to carotid-femoral pulse wave velocity(P<0.001). Results were independent of age, treatment, mean blood pressure, and indexed LV mass.

CONCLUSIONS

In hypertensive individuals, greater basal LV torsion was associated with increased aortic stiffness and improved diastolic function. These changes may compensate for the deleterious effects of aortic stiffening on LV relaxation.