Impact of arterial elastance as a measure of vascular load on left ventricular geometry in hypertension

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.

Arterial Elastance: A Predictor of Hypotension Due to Anesthesia Induction

BACKGROUND

Hypotension is common after anesthesia induction and may have adverse outcomes. The aim of this study was to investigate whether arterial elastance (Ea) is a predictor of post-induction hypotension.

METHODS

Between January and June 2022, the hemodynamic parameters of 85 patients who underwent major surgery under general anesthesia were prospectively evaluated. The noncalibrated pulse contour device MostCare (Vytech, Vygon, Padua, Italy) was used to measure hemodynamic parameters before and after anesthesia induction. The duration of the measurements was determined from one minute before induction to 10 min after induction. Hypotension was defined as a greater than 30% decrease in mean arterial pressure from the pre-induction value and/or systolic arterial pressure of less than 90 mmHg. The patients were divided into post-induction hypotension (-) and (+) groups. For the likelihood of post-induction hypotension, a multivariate regression model was used by adding significantly different pre-induction parameters to the post-induction hypotension group.

RESULTS

The incidence of post-induction hypotension was 37.6%. The cut-off value of the pre-induction Ea for the prediction of post-induction hypotension was ≥1.08 mmHg m^-2mL^-1 (0.71 [0.59-0.82]). In the multivariate regression model, the likelihood of postinduction hypotension was 3.5-fold (1.4-9.1), increased by only an Ea ≥ 1.08 mmHg m^-2mL^-1.

CONCLUSION

Pre-induction Ea showed excellent predictability of hypotension during anesthetic induction and identified patients at risk of general anesthesia induction-related hypotension.

A meta-analysis of the haemodynamics of primary hypertension in children and adults

We performed a systematic review and meta-analysis to determine the relative contributions of elevated cardiac output and systemic vascular resistance to hypertension in children and adults. This included 27 studies on 11 765 hypertensive and normotensive children and adults in whom cardiac output was measured. Cardiac output but not systemic vascular resistance was elevated in hypertensive compared to normotensive children and young adults (difference in means 1.15 [0.78-1.52] l/min, P < 0.001). In older hypertensive adults, both were elevated compared to normotensive individuals (0.40 [0.26-0.55] l/min, P < 0.001 and 3.21 [1.91-4.51] mmHg min/l, P < 0.001 for cardiac output and systemic vascular resistance, respectively). The main haemodynamic alteration in primary hypertension (including obesity-hypertension) in both children and young to middle-aged adults is an elevation of cardiac output. With longer duration and greater severity of hypertension there may be progression from a 'cardiac' to a 'vascular' phenotype with increased systemic vascular resistance.

Sex Differences in Molecular Mechanisms of Cardiovascular Aging

Cardiovascular disease (CVD) is still the leading cause of illness and death in the Western world. Cardiovascular aging is a progressive modification occurring in cardiac and vascular morphology and physiology where increased endothelial dysfunction and arterial stiffness are observed, generally accompanied by increased systolic blood pressure and augmented pulse pressure. The effects of biological sex on cardiovascular pathophysiology have long been known. The incidence of hypertension is higher in men, and it increases in postmenopausal women. Premenopausal women are protected from CVD compared with age-matched men and this protective effect is lost with menopause, suggesting that sex-hormones influence blood pressure regulation. In parallel, the heart progressively remodels over the course of life and the pattern of cardiac remodeling also differs between the sexes. Lower autonomic tone, reduced baroreceptor response, and greater vascular function are observed in premenopausal women than men of similar age. However, postmenopausal women have stiffer arteries than their male counterparts. The biological mechanisms responsible for sex-related differences observed in cardiovascular aging are being unraveled over the last several decades. This review focuses on molecular mechanisms underlying the sex-differences of CVD in aging.

Prolonged Asynchronous Left Ventricular Isovolumic Relaxation Constant in Ascending Compared to Descending Thoracic Aortic Stenosis for Chronic Early Left Ventricular Afterload and Late Left Ventricular Afterload Increase

Background: In arterial hypertension, left ventricular relaxation is affected early on in relation to a chronic difference in peak left ventricular afterload with early development of HF. Objective: in ascending compares to descending thoracic aortic stenosis, resulting in chronic late and early LV afterload increase, to assess the left ventricular isovolumic relaxation pressure decay constant through regression analysis, a parameter of left ventricular relaxation on the 4th and 8th week period from invasive left ventricular pressure measurements. Methods: fourteen pigs underwent posterolateral thoracotomy for ascending aortic stenosis, resulting in chronic early left ventricular afterload increase (EL = 6], or descending thoracic aortic stenosis creating chronic late systolic left ventricular load (LL = 8]. Exponential regression with nonzero asymptote for τ assessment, with linear and nonlinear regression were performed on isovolumic relaxation pressure decay from the left ventricular invasive pressure measurements on 4th and 8th week. Two-way repeated measurement ANOVA, post-hoc Tukey test and linear regression were performed for statistical analysis. Results presented are mean ± SEM or median (quartiles], with significance is at p < 0.05. Results: The ascending aortic stenosis associated with prolonged biexponential asynchronous τ, compared to the descending thoracic aorta stenosis, resulted in data that were different at the 8^th week in presence of respirations (interaction p < 0.05]. Monoexponential and linear τ were not different in either respiration being preserved or suspended transitionally and in preload reduction. Preload sensitive response of τ was found in ascending compared to descending thoracic aortic banding that reduced in EL and in LL it increased with load reduction (p < 0.05]. These results indicated that τ is not different in and between LV afterloading conditions in a chronic setting, although it indicates that myocardial ischemia is present and that it is greater in ascending aortic banding, compared to descending thoracic aorta banding at the 8th week. Conclusion: In different sequence of the left ventricular afterload, ventricular relaxation is affected early on, having in EL compared to LL prolonged biexponential asynchronous left ventricular relaxation constant, thus indicating the development left ventricular myocardial ischemia and different elastic recoil in an invasive left ventricular hemodynamic assessment.

Feasibility of the contraction-relaxation coupling index in outcome prediction for patients with acute heart failure

AIMS

Contemporary heart failure (HF) classification based on left ventricular (LV) ejection fraction is limited for comprehensive assessment of LV function. We aimed to validate the feasibility of the contraction-relaxation coupling index (CRC) as a novel predictor for clinical outcomes in patients with acute HF.

METHODS AND RESULTS

A total of 3266 consecutive patients (median age: 74 years, 53% male) with acute HF were included. CRC was defined as the ratio of end-diastolic elastance (LV end-diastolic pressure/stroke volume) to end-systolic elastance (LV end-systolic pressure/end-systolic volume). The risk for 1 year composite endpoint of all-cause mortality or hospitalization for HF (primary outcome) was compared after group categorization using CRC tertiles (Tertile 1: CRC ≤ 0.17, Tertile 2: 0.17 < CRC ≤ 0.40, and Tertile 3: 0.40 < CRC). The median CRC was 0.3 and the median LVEF was 42%. After adjustment for clinical and echocardiographic covariates, CRC was an independent predictor for the primary outcome (hazard ratio [HR]: 1.74, 95% confidence interval [CI]: 1.47-2.07 in Tertile 3 and HR: 1.21, 95% CI: 1.02-1.44 in Tertile 2 when compared with Tertile 1; HR: 1.23, 95% CI: 1.14-1.33 per one-standard deviation increment in CRC). The risk model with CRC showed better performance in outcome discrimination than the model with LVEF (c-statistic 0.701 vs. 0.699, P for difference <0.001). Patients with higher CRC demonstrated better effectiveness of neurohormonal blockade for the primary outcome compared with those with lower CRC (HR: 0.38, 95% CI: 0.29-0.50 in Tertile 3 and HR: 0.67, 95% CI: 0.52-0.89 in Tertile 1).

CONCLUSIONS

CRC provides an independent value for outcome prediction in patients with acute HF. CRC would be a sensitive indicator for prognostic risk stratification and for predicting treatment response to the neurohormonal blockade.

Longitudinal uncoupling of the heart and arteries with aging in a community-dwelling population

Although mechanical energy transfer between the heart and arterial system, referred to as arterial-ventricular (AV) coupling, is an important determinant of cardiovascular performance, how AV coupling changes over time within and among individuals as they age has not been fully explored. We studied 129 participants (baseline age 21-96) of the Baltimore Longitudinal Study of Aging, free of clinical CVD. Participants underwent repeated multigated cardiac blood pool scans to estimate left ventricular (LV) volumes (SV, EDV, and ESV). Total systemic vascular resistance (TSVR), total arterial compliance (TAC), effective arterial elastance (Ea), and end-systolic LV elastance (Elv) were calculated using LV volumes and brachial BP measurements; calculated Ea/Elv was the measure of AV coupling. Linear mixed-effects models were used to estimate person-specific rates of change (Change) for each variable. The rate at which Ea increased over time was faster than the rate at which Elv increased, resulting in AV uncoupling (increased Ea/Elv) over time that was significantly greater in women than in men. Loss of arterial compliance was the main determinant of (Ea/Elv)_Change, which was negatively associated with changes in SV and EDV but positively with changes in ESV. Progressive AV uncoupling occurred with aging and was more pronounced in women than men. While Ea change did not differ by sex, Elv increased at a slower rate in women than in men. AV uncoupling was inversely associated with EDV and SV rates of change and a directly associated with an increase in ESV rate of change. Additional studies are needed to explore the functional consequences of AV uncoupling in healthy individuals with respect to the emergence of age-associated clinical cardiovascular diseases, such as heart failure with preserved ejection fraction.

Sex Differences in Cardiovascular Aging and Heart Failure

PURPOSE OF THE REVIEW

This review summarizes sex-related changes in the heart and vasculature that occur with aging, both in the presence and absence of cardiovascular disease (CVD).

RECENT FINDINGS

In the presence of CVD risk factors and/or overt CVD, sex-specific changes in the number of cardiomyocytes, extent of the myocardial extracellular matrix, and myocellular hypertrophy promote unique patterns of LV remodeling in men and women. In addition, age- and sex-specific vascular stiffening is also well established, driven by changes in endothelial dysfunction, elastin-collagen content, microvascular dysfunction, and neurohormonal signaling. Together, these changes in LV chamber geometry and morphology, coupled with heightened vascular stiffness, appear to drive both age-related increases in systolic function and declines in diastolic function, particularly in postmenopausal women. Accordingly, estrogen has been implicated as a key mediator, given its direct vasodilating properties, association with nitric oxide excretion, and involvement in myocellular Ca2+ handling, mitochondrial energy production, and oxidative stress. The culmination of the abovementioned sex-specific cardiac and vascular changes across the lifespan provides important insight into heart failure development, particularly of the preserved ejection fraction variety, while offering promise for future preventive strategies and therapeutic approaches.

Doppler indexes of left ventricular systolic and diastolic function in relation to haemodynamic load components in a general population

BACKGROUND

The contribution of central pulsatility to left ventricular (LV) dysfunction might be mediated by the haemodynamic loads of forward (Pf) and backward (Pb) pulse waves. We investigated the relation between echocardiographic indexes of LV function and pulsatile loads derived by wave separation analysis (WSA).

METHODS

In 755 participants, we assessed LV dimensions, transmitral blood flow and mitral annular tissue velocities. We derived central pulse pressure (cPP) from radial tonometric recordings and calculated Pf, Pb and their ratio (reflection magnitude) using an automated, pressure-based WSA algorithm. Despite good quality recordings, WSA failed to derive Pf and Pb in 139 participants (18.4%), in particular in older women with unfavourable haemodynamics. Thus, our analysis included 616 participants (46.1% women; mean age, 49.2 years).

RESULTS

Age and age explained most of the variance in cPP (36.9%), Pf (18.6%), Pb (41.5%) and reflection magnitude (36.7%; P < 0.0001) and altered the direct correlation between Pf and Pb (Pint < 0.0001). Haemodynamic loads were independently associated with sex, BMI, heart rate, mean arterial pressure, history of diabetes and use of antihypertensive drugs. In multivariable-adjusted analyses, transmitral velocities and E/e' ratio increased with higher cPP, Pf and Pb in men and women. We also observed an age-dependent association of LV radial strain with cPP, Pf and Pb.

CONCLUSION

The commercial WSA algorithm holds limited clinical utility given its low feasibility in older participants with unfavourable haemodynamics. LV function indexes were similarly associated with Pf and Pb, favouring the use of the composite cPP for prediction of LV dysfunction.

Impact of left ventricular concentricity on long-term mortality in a hospital-based population in Japan

Background

The prognostic impact of relative wall thickness (RWT), ventricular concentricity, is controversial.

Methods

We retrospectively analyzed data obtained from 4444 consecutive patients who had undergone both transthoracic echocardiography and electrocardiography at our hospital in 2013. Those who presented with a history of previous episodes of myocardial infarctions and severe or moderate valvular disease were excluded from the analysis. We calculated RWT as follows: (2 x diastolic posterior wall thickness) / (the diastolic LV dimension). We defined high RWT as a ratio > 0.42. A total of 3654 patients were categorized into two groups: 492 with high RWT, and 3162 with normal RWT.

Results

The mean ages of those in the normal and high RWT groups were 64.6 (±standard deviation 16.3) and 71.6 (± 12.7) years, respectively (p<0.001). Prevalence of male sex, history of diabetes, hypertension, and chronic kidney disease, and the left atrium volume index was higher for the high RWT group than for the normal RWT group. The median follow-up period was 1274 days (interquartile range, 410–1470). The Kaplan-Meier curves showed a constant increase in all-cause death, with cumulative 3-year incidences of 18.3% and 10.8% for the high RWT and normal RWT groups, respectively (log-rank p<0.001). After adjusting for confounders, the increased mortality risk for those with high RWT relative to normal RWT was significant (hazard ratio, 1.64; 95% confidence interval, 1.27–2.10). This trend was consistent for the composite of deaths and major adverse cardiac events.

Conclusion

High RWT has a deleterious impact on long-term mortality.

Arterial-ventricular coupling and parameters of vascular stiffness in hypertensive patients: Role of gender

Objective

Non-invasive estimation of arterial–ventricular coupling has been extensively used for the evaluation of cardiovascular performance, however, a relative small amount of data is available regarding arterial–ventricular coupling and its components in hypertension. The present study was designed to investigate the relationship between left ventricular elastance, arterial elastance, parameters of vascular stiffness and the influence of gender in a population of hypertensive individuals.

Methods

In 102 patients, trans-thoracic cardiac ultrasound, parameters of aortic stiffness (carotid-femoral pulse wave velocity) and wave reflection (augmentation index) were recorded. Ultrasound images of common carotid arteries were acquired for the assessment of intima-media thickness as well as carotid compliance and distensibility coefficient.

Results

Mean age was 61 years, 32% diabetes, 56% dyslipidemia, 9% previous cardiovascular events; women (n = 32) and men were superimposable for cardiovascular risk factors prevalence. In the population, ventricular elastance was significantly correlated with arterial elastance (r = 0.887), age (r = 0.334), gender (r = −0.494), BMI (r = −0.313), augmentation index (r = 0.479) (all p < 0.001); and with carotid compliance and distensibility coefficient (r = 0.229 and r = − 0.250, respectively, both p < 0.05); however, only arterial elastance and gender were independently associated with ventricular elastance in multiple regression models adjusted for confounding factors. Gender-specific analysis revealed that arterial elastance and augmentation index remained statistically significant associated with ventricular elastance in men (r = 0.275, p = 0.04); instead augmentation index was no longer significant (r = 0.052, p = 0.77) in the female sex.

Conclusions

In hypertensive patients, main determinants of ventricular elastance are arterial elastance, as an integrated index of arterial vascular load, and gender; however, pressure augmentation might play an additional role in men.

Ventricular-arterial coupling assessment using gated single-photon emission computed tomography: relationship with reserve pulse pressure and repolarization abnormalities

AIMS

In patients with normal myocardial perfusion, ST-segment depression and reserve pulse pressure (rPP) can identify patients at higher risk of cardiovascular events. We aimed to explore the prevalence of impaired ventricular-arterial coupling (VAc) in patients with normal myocardial perfusion imaging and its relationship with ST-segment depression and rPP.

METHODS AND RESULTS

The present study included consecutive patients with normal myocardial perfusion imaging by single-photon emission computed tomography and ST-segment depression. Stroke volume, end-systolic pressure, arterial elastance (Ea), ventricular elastance (Ev), and VAc (Ea/Ev) were estimated both at rest and during stress. The difference between stress and rest (ΔVAc) was calculated. A positive ΔVAc was considered an impaired ΔVAc (iVAc).

RESULTS

A total of 92 patients were prospectively included. iVAc was identified in 44 (59%) patients with ST-segment depression compared with 3 (16%) patients with normal repolarization (P=0.001). A higher incidence of abnormal rPP was identified in patients with ST-segment depression compared with the control group (61 vs. 16%, P=0.0001). ST-segment depression was identified as the only independent predictor of iVAc (adjusted OR 7.5; 95% CI 1.9-30.0, P=0.004).

CONCLUSION

Noninvasive assessment of VAc is feasible with gated single-photon emission computed tomography and appears to be related to ST-segment depression and reserve rPP.

Gender Differences in Ventricular-vascular Coupling Following Exercise

OBJECTIVE

To study the differences of cardiovascular system between men and women in response to exercise stress.

METHODS

Forty healthy youth were tested according to Bruce protocol of exercise stress. They were detected by ultrasonography during the rest, peak exercise, and recovery stages, respectively. The left ventricular diastolic elastance (Ed), effective arterial elastance (Ea), left ventricular end-systolic elatance (Ees), ventricular-vascular coupling index (VVI), and total stiffness index (TSI) were measured and calculated according to the formulas. The results of all stages were compared according to genders.

RESULTS

All stages, the Ed, TSI, and VVI of women were higher than those of men, but the Ees was lower than that of men (all P<0.05); there was no significant difference in Ea between men and women. The Ed, Ees, Ea, and TSI were closely related with left ventricular oxygen consumption and heart function, and women showed more closely. Before and after exercise, the changes were different in Ed, Ees, Ea, TSI, and VVI (all P<0.05), and VVI changed least.

CONCLUSIONS

Before and after exercise, the ventricular stiffness matched well with arterial stiffness and maintained within a narrow range. For women, the tolerance of exercise was lower than that of men.

Abnormal stress-related measures of arterial stiffness in middle-aged and elderly men and women with impaired fasting glucose at risk for a first episode of symptomatic heart failure

Background

Abnormal resting arterial stiffness is present in middle‐aged and elderly persons with abnormalities of fasting glucose (diabetes or impaired fasting glucose) and is associated with exercise intolerance. We sought to determine whether these same persons exhibited stress‐related abnormalities of arterial stiffness.

Methods and Results

We analyzed dobutamine magnetic resonance stress imaging results from 373 consecutively recruited persons aged 55 to 85 years with normal fasting glucose, impaired fasting glucose, or diabetes who were at risk for but without symptomatic heart failure. Personnel blinded to participant identifiers measured arterial stiffness (brachial pulse pressure/left ventricular stroke volume indexed to body surface area, the aortic elastance index [brachial end‐systolic pressure/left ventricular stroke volume indexed to body surface area], and thoracic aortic distensibility) at 80% of the maximum predicted heart rate response for age. Participants averaged 69±8 years of age; 79% were white, 92% were hypertensive, and 66% were women. After accounting for hypertension, sex, coronary artery disease, smoking, medications, hypercholesterolemia, and visceral fat, we observed an effect of glycemic status for stress measures of arterial stiffness in those with diabetes and impaired fasting glucose relative to those with normal fasting glucose (P=0.002, P=0.02, and P=0.003, respectively).

Conclusion

Middle‐ and older‐aged individuals with diabetes or impaired fasting glucose have higher stress measures of arterial stiffness than those with normal fasting glucose. These data emphasize the need for future studies with larger sample sizes to determine whether stress‐related elevations in arterial stiffness are related to exercise intolerance and future episodes of heart failure experienced by those with abnormalities of fasting glucose.

Clinical Trial Registration

URL: http://clinicaltrials.gov/. Unique identifier: NCT00542503.

Sex differences in ventricular-vascular coupling following endurance training

Introduction

Ventricular and vascular coupling is defined as the ratio of arterial elastance (Ea) to ventricular elastance (Elv) and describes the interaction between the heart and arterial system. There are sex differences in both arterial and ventricular function in response to both acute exercise and aerobic exercise training.

Purpose

To examine the effects of aerobic exercise training on elastances and the coupling ratio in young adult men and women. We hypothesized a reduction in the coupling ratio in both sexes due to a decrease in Ea that would be more pronounced in men and an increase in Elv that would be larger in women.

Methods

Fifty-three healthy, young adults completed the study. Central pulse wave velocity and heart volumes were measured before and after an 8-week aerobic training intervention. Elastances were calculated as Ea = end-systolic pressure/stroke volume and Elv = end-systolic pressure/end-systolic volume and indexed to body surface area.

Results

After the intervention, women augmented indexed and un-indexed Elv from 2.09 ± 0.61 to 2.52 ± 0.80 mmHg/ml, p < 0.05, and reduced the coupling ratio from 0.72 ± 18 to 0.62 ± 15, p < 0.05, while men maintained their pre-training ratio (from 0.66 ± 0.20 to 0.74 ± 0.21, p > 0.05). Women also reduced end-systolic pressure (from 91 ± 10 to 87 ± 10 mmHg), and both groups reduced central pulse wave velocity (from 6.0 ± 1.0 to 5.6 ± 0.6 m/s, p < 0.05).

Conclusion

We conclude that after 8 weeks of aerobic training, only women reduced their coupling ratio due to an increase in Elv. This suggests that aerobic exercise training elicits sex-dependent changes in the coupling ratio in young, healthy individuals.

Aortic stiffness and hypotension episodes are associated with impaired cognitive function in older subjects with subjective complaints of memory loss

OBJECTIVE

Though CV risk factors and markers of arterial aging are recognized risky for cognition, no study has simultaneously investigated the impact of multiple cardiac, arterial (large and small vessels), and hemodynamic parameters on cognitive function in older subjects.

METHODS

Two hundred eighty older subjects with subjective complaints of memory loss and no previous stroke (mean age 78.3 ± 6.3 years) were studied. Global cognitive function was evaluated with the Mini-Mental State Examination (MMSE). Cognitive impairment was defined as a MMSE < 21. We measured: traditional CV risk factors; aorta stiffness (Pulse Wave Velocity, PWV); LV mass; presence of WML at neuroimaging; episodes of hypotension (SBP <100 mmHg during 24 h Ambulatory Blood Pressure Monitoring).

RESULTS

In both cross-sectional and longitudinal analyses PWV, WML, and episodes of hypotension were significantly associated with poorer cognitive function-controlling for age, sex, education, depression, traditional CV risk factors, and medications. LV mass was no longer associated with cognition in multiple regression. Older subjects with stiffer arteries or episodes of hypotension presented a 4-fold and an 11-fold, respectively, greater odds for progression from normal cognitive function to cognitive impairment. A synergistic effect between PWV, WML, and hypotension was observed: the occurrence of any two of PWV, WML, or hypotension was accompanied by lower MMSE; in the presence of all three factors, a further significant decline in cognitive function was observed.

INTERPRETATION

Systemic hemodynamic parameters (higher PWV and hypotension) together with cerebral microvascular damage (WML) are significantly associated with poorer cognitive function and may identify older subjects with subjective complaints of memory loss at higher risk of cognitive decline.

Left Ventricular Energy Model Predicts Adverse Events in Women With Suspected Myocardial Ischemia: Results From The NHLBI-Sponsored Women's Ischemia Syndrome Evaluation (WISE) Study

OBJECTIVES

To assess the prognostic value of a left ventricular energy-model in women with suspected myocardial ischemia.

BACKGROUND

The prognostic value of internal energy utilization (IEU) of the left ventricle in women with suspected myocardial ischemia is unknown.

METHODS

Women (n=227, mean age 59±12 years, range 31-86), with symptoms of myocardial ischemia, underwent myocardial perfusion imaging (MPI) assessment for regional perfusion defects along with measurement of ventricular volumes separately by gated Single Photon Emission Computed Tomography (SPECT) (n= 207) and magnetic resonance imaging (MRI) (n=203). During follow-up (40±17 months), time to first major adverse cardiovascular event (MACE, death, myocardial infarction or hospitalization for congestive heart failure) was analyzed using MRI and gated SPECT variables.

RESULTS

Adverse events occurred in 31 (14%). Multivariable Cox models were formed for each modality: IEU and wall thickness by MRI (Chi-squared 34, p<0.005) and IEU and systolic blood pressure by gated SEPCT (Chi-squared 34, p<0.005). The models remained predictive after adjustment for age, disease history and Framingham risk score. For each Cox model, patients were categorized as high-risk if the model hazard was positive and not high-risk otherwise. Kaplan-Meier analysis of time to MACE was performed for high-risk vs. not high-risk for MR (log rank 25.3, p<0.001) and gated SEPCT (log rank 18.2, p<001) models.

CONCLUSIONS

Among women with suspected myocardial ischemia a high internal energy utilization has higher prognostic value than either a low EF or the presence of a myocardial perfusion defect assessed using two independent modalities of MR or gated SPECT.

The relationship between ventricular-vascular uncoupling during exercise and impaired left ventricular longitudinal functional reserve in hypertensive patients

Uncoupling between heart and vessel may be accompanied by left ventricular (LV) dysfunction during exercise. We investigated the association between ventricular-vascular uncoupling during exercise and impaired LV longitudinal functional reserve in hypertensive subjects. Supine bicycle exercise echocardiography (25-watt, 3-minute increments) was performed in 216 hypertensive patients (106 male; mean age, 58 ± 9 years). Arterial elastance (Ea), end-systolic ventricular elastance (Ees), and ventricular-vascular interaction (VVI) index (Ea/Ees) were calculated at rest and at each stage of exercise. The patients were divided into three groups according to the tertile value of VVI ratio. The VVI ratio was defined as the ratio of VVI index at 50 W exercise over VVI index at rest; normal VVI response (n = 72); borderline VVI response (n = 72); and abnormal VVI response (n = 72). There were no significant differences in conventional echo parameters, mitral inflow velocities, mitral annular early diastolic (E') velocity, and mitral annular systolic velocity (S') at rest among the three groups. However, E' velocities and S' velocities at 25 W and 50 W were significantly lower in patients with abnormal VVI response compared with those in the other groups (P = .010 at 25 W, P = .008 at 50 W in E' velocity; P = .022 at 25 W, P = .043 at 50 W in S' velocity). Longitudinal diastolic functional reserve index from rest to 50 W was significantly lower in patients with abnormal VVI response compared with the other groups. Ventricular-vascular uncoupling during exercise was related to impaired LV longitudinal functional reserve in hypertensive patients.

Impact of hypertension on ventricular-arterial coupling and regional myocardial work at rest and during isometric exercise

BACKGROUND

To understand better the mechanism of left ventricular (LV) remodeling related to hypertension, it is important to evaluate LV function in relation to the changes in loading conditions. The aim of this study was to investigate changes in conventional ventricular-arterial coupling indexes, LV strain, and a new index reflecting regional myocardial work assessed noninvasively at rest and during isometric exercise in a random sample including participants with normal blood pressure and those with hypertension.

METHODS

A total of 148 participants (53.4% women; mean age, 52.0 years; 39.2% with hypertension) underwent simultaneous echocardiographic and arterial data acquisition at rest and during increased afterload (handgrip exercise). End-systolic pressure was determined from the carotid pulse wave. Arterial elastance (Ea) and LV elastance (Ees) were calculated as end-systolic pressure/stroke volume and end-systolic pressure/end-systolic volume. Doppler tissue imaging and two-dimensional speckle tracking were used to derive LV longitudinal strain. Regional myocardial work (ejection work density [EWD]) was the area of the pressure-strain loop during ejection.

RESULTS

At rest, with adjustments applied, Ees (3.06 vs 3.71 mm Hg/mL, P = .0003), Ea/Ees (0.54 vs 0.47, P = .002) and EWD (670 vs 802 Pa/m(2), P = .0001) differed significantly between participants with normal blood pressure and those with hypertension. During handgrip exercise, Ea and Ea/Ees significantly increased (P < .0001) in both groups. Doppler tissue imaging and two-dimensional LV strain decreased in participants with hypertension (P ≤ .008). Only in subjects with normal blood pressure EWD significantly increased (+14.7%, P = .0009).

CONCLUSIONS

Although patients with hypertension compared with those with normal blood pressure have increased LV systolic stiffness and regional myocardial work to match arterial load at rest, they might have diminished cardiac reserve to increase myocardial performance, as estimated by EWD during isometric exercise.

Arterial-ventricular coupling with aging and disease

Age is the dominant risk factor for cardiovascular diseases. Understanding the coupling between the left ventricle (LV) and arterial system, termed arterial-ventricular coupling (E(A)/E(LV)), provides important mechanistic insights into the complex cardiovascular system and its changes with aging in the absence and presence of disease. E(A)/E(LV) can be indexed by the ratio of effective arterial elastance (E(A); a measure of the net arterial load exerted on the LV) to left ventricular end-systolic elastance (E(LV); a load-independent measure of left ventricular chamber performance). Age-associated alterations in arterial structure and function, including diameter, wall thickness, wall stiffness, and endothelial dysfunction, contribute to a gradual increase in resting E(A) with age. Remarkably there is a corresponding increase in resting E(LV) with age, due to alterations to LV remodeling (loss in myocyte number, increased collagen) and function. These age-adaptations at rest likely occur, at least, in response to the age-associated increase in E(A) and ensure that E(A)/E(LV) is closely maintained within a narrow range, allowing for optimal energetic efficiency at the expense of mechanical efficacy. This optimal coupling at rest is also maintained when aging is accompanied by the presence of hypertension, and obesity, despite further increases in E(A) and E(LV) in these conditions. In contrast, in heart failure patients with either reduced or preserved ejection fraction, E(A)/E(LV) at rest is impaired. During dynamic exercise, E(A)/E(LV) decreases, due to an acute mismatch between the arterial and ventricular systems as E(LV) increases disproportionate compared to E(A) (≈200 vs. 40%), to ensure that sufficient cardiac performance is achieved to meet the increased energetic requirements of the body. However, with advancing age the reduction in E(A)/E(LV) during acute maximal exercise is blunted, due to a blunted increase E(LV). This impaired E(A)/E(LV) is further amplified in the presence of disease, and may explain, in part, the reduced cardiovascular functional capacity with age and disease. Thus, although increased stiffness of the arteries itself has important physiological and clinical relevance, such changes also have major implications on the heart, and vice versa, and the manner in the way they interact has important ramifications on cardiovascular function both at rest and during exercise. Examination of the alterations in arterial-ventricular coupling with aging and disease can yield mechanistic insights into the pathophysiology of these conditions and increase the effectiveness of current therapeutic interventions.

Correlation of arterial blood pressure and compliance with left ventricular structure and function in the very elderly

There are very few data on the relationship between systolic blood pressure (SBP), diastolic blood pressure (DBP), arterial compliance, and left ventricular structure and function, particularly left ventricular hypertrophy (LVH), in the very elderly (>75 years). SBP and arterial stiffness increase with age, and the question is: which of the two is the main stimulus to LVH? This is a cross-sectional study to compare blood pressure and arterial stiffness measures with regard to their correlations with echocardiographic parameters of LV structure and function, controlling for age and cardiovascular risk factors, in a very elderly population. Arterial stiffness was determined by radial pulse waveform using pulse contour analysis. LV dimensions were measured by transthoracic M-mode echocardiography, and diastolic function by tissue Doppler measurements of diastolic mitral annular velocities. There were 179 subjects, all male, with a mean age of 81.8 years. Using age-adjusted partial correlations, SBP, DBP, and mean arterial pressure (MAP) were correlated with parameters of LV structure and function. Correlation coefficients were: SBP versus left ventricular mass index (LVMI), r = 0.246; SBP versus early diastolic mitral annular velocity (MAV), r = -0.179; DBP versus LVMI, r = 0.199; DBP versus MAV, r = -0.199; MAP versus LVMI, r = 0.276; and MAP versus MAV, r = -0.206, all with P < .05. However, neither capacitative nor reflective arterial compliance was significantly correlated with any parameter of LV structure and function. After controlling for age and 10 cardiovascular and metabolic risk factors, the correlation between blood pressure and the measured LV parameters was substantially unchanged, as was the lack of correlation between indices of arterial compliance and the LV indices. Arterial blood pressure is correlated with LV structure and function in the very elderly, but arterial stiffness, as measured by diastolic pulse contour analysis, is not.

The relationship between renal impairment and left ventricular structure, function, and ventricular-arterial interaction in hypertension

OBJECTIVES

Our objective was to define the relationship between renal dysfunction--both albuminuria and reduced estimated glomerular filtration rate (eGFR)--and cardiac structure and diastolic dysfunction among patients with chronic hypertension.

METHODS

Both albuminuria and eGFR were measured in 540 asymptomatic patients with hypertension and diastolic dysfunction assessed by reduced early mitral annular relaxation velocity (E'). The majority of patients were white, mean age was 60 ± 10 years, mean SBP was 149 ± 18 mmHg, and there was a low prevalence comorbid conditions. Albuminuria was undetectable in 148 (27%), within the normal to low range [urine albumin-to-creatinine ratio (UACR) 1-25 mg/g for men, 1-17 mg/g for women] in 292 (54%), and high or very high (UACR >25 mg/g for men, >17 mg/g for women) in 100 (19%). Estimated GFR was 60 ml/min per 1.73 m² or less in 75 (14%), 61-90 ml/min per 1.73 m² in 244 (45%), and more than 90 ml/min per 1.73 m² in 221 (41%).

RESULTS

Albuminuria, even within the normal range, was associated with greater left ventricular wall thickness (P = 0.01), higher relative wall thickness (P = 0.004), worse diastolic function reflected in lower E' (P = 0.01), greater arterial and left ventricular end-systolic stiffness (P < 0.0001 and P = 0.003, respectively), and higher N-terminal pro-brain natriuretic peptide (NT-proBNP) level (P = 0.0025), even after adjustment for differences in baseline characteristics. In contrast, no independent relationship was observed between eGFR and parameters of cardiac structure or function.

CONCLUSION

Among asymptomatic hypertensive patients with evidence of diastolic dysfunction, the presence of albuminuria, even within the normal range, is associated with greater concentric remodeling, greater left ventricular end-systolic stiffness, and worse diastolic function.

Relationship between arterial impedance and concentric remodeling in patients with normal systolic function: impact on prevalence and survival

Although concentric remodeling (CR) is associated with increased morbidity and mortality, little is known regarding the interaction of arterial impedance (IMP) on survival in CR. The authors evaluated 50,421 patients with normal systolic function to assess prevalence of CR and impact of CR and IMP on survival (mean follow-up, 3.9±2.3 years.) In 2636 patients with paired echocardiograms, the authors assessed the impact of IMP on mortality, based on maintaining a high or low IMP (> or <4.0 mm Hg/mL/m(2) ). CR occurred in 21% of patients and was associated with twice the mortality compared with patients with normal left ventricular (LV) structure (P<.0001). The prevalence of CR increased with increasing IMP (P<.001 for trend). In the paired cohort, CR patients with an IMP <4.0 had a mortality of 6.3%, with 58% converting to normal LV structure, whereas mortality was higher (10%; P<.0001) and conversion to normal LV structure was less frequent (46%; P<.001) in those whose IMP remained ≥4.0. CR is prevalent and associated with high mortality and increases with higher IMP. Reducing IMP levels in CR is associated with lower mortality and greater conversion to normal LV structure. Studies are needed to determine whether reporting and targeting IMP is beneficial in CR.

Telmisartan improves morphologic and functional changes in both left ventricular myocardium and carotid arterial wall in patients with hypertension: assessment by tissue Doppler imaging and carotid ultrasonography

OBJECTIVE

The aim of the present study was to clarify the beneficial effects of telmisartan on the morphologic and functional changes in left ventricular (LV) myocardium and carotid arterial wall in patients with hypertension (HT) using tissue Doppler imaging and carotid ultrasonography.

METHODS

Telmisartan (20-40 mg daily) was administered to 35 previously untreated patients with HT. Conventional and pulsed tissue Doppler echocardiography were performed after medication had been continued for 1-2 months with normal values for blood pressure (BP) (phase I) and for 12 months (phase II). Subclinical atherosclerosis also was determined by measuring the intima-media thickness (IMT) and stiffness β of the left and right common carotid arteries using B- and M-mode ultrasonography.

RESULTS

In the phase II, the LV mass index and isovolumic relaxation time were lower, the peak systolic and early diastolic mitral annular motion velocities were greater compared to the phase I. The stiffness β and mean IMT were lower in the phase II than in the phase I. On multivariate regression analyses, age, BP, and LV diastolic variables emerged as stronger predictors of carotid arterial IMT and stiffness β.

CONCLUSIONS

The 1-year use of telmisartan improved LV hypertrophy, regional LV myocardial contraction and relaxation, and carotid atherosclerosis in patients with HT. Our results support cardio- and arterioprotective benefits from continuous long-term telmisartan monotherapy, and combined analysis of tissue Doppler imaging and carotid ultrasonography may be a useful tool for understanding ventriculoarterial coupling in patients with HT.

Relation of flow-mediated dilation to global arterial load: impact of hypertension and additional cardiovascular risk factors

BACKGROUND

Endothelial dysfunction may be related to increased left ventricular (LV) mass due to an association between endothelial dysfunction with increased arterial load. Therefore, we evaluated whether brachial artery flow-mediated dilation (FMD) is related to global arterial load.

METHODS

Pulse pressure/stroke index (PP/SVi, global arterial stiffness, prognostically validated), stroke volume/PP (SV/PP, global arterial compliance), and % of the predicted SV/PP by heart rate, age and body weight (confounder-adjusted global compliance, prognostically validated) were used as LV geometry-related indices of global arterial load.

RESULTS

Compared to normotensive participants (NT, n = 50), those with hypertension (HTN, n = 51) had lower FMD (8.3% ± 5.4 vs. 12.8% ± 6.5), higher PP/SVi (1.24 ± 0.34 vs. 1.04 ± 0.28 mmHg m(2)/ml), higher LV mass and higher relative wall thickness (all p < 0.01); in contrast, SV/PP and % of predicted SV/PP did not differ between NT and HTN (all p>0.1). Impaired FMD was 3-4-fold more prevalent than LV hypertrophy or increased arterial load both in NT and in HTN. Within NT and HTN separately, PP/SVi, SV/PP and % of predicted SV/PP were comparable among tertiles of FMD. Only in NT, lower FMD was associated with higher peak exercise systolic BP (p < 0.05). In multivariable regression models, FMD was not associated with indices of arterial load independently (all p > 0.1).

CONCLUSIONS

In young-to-middle-age subjects with cardiovascular risk factors, impaired FMD is more prevalent than traditional preclinical manifestation of cardiovascular disease, and may exist independent to increased arterial load. Thus, endothelial dysfunction assessment may refine cardiovascular risk profile and risk-reduction strategies based on detection of traditional target organ damage.

Single-beat estimation of the left ventricular end-systolic pressure-volume relationship in patients with heart failure

AIM

The end-systolic pressure-volume relationship (ESPVR) constructed from multiple pressure-volume (PV) loops acquired during load intervention is an established method to asses left ventricular (LV) contractility. We tested the accuracy of simplified single-beat (SB) ESPVR estimation in patients with severe heart failure.

METHODS

Nineteen heart failure patients (NYHA III-IV) scheduled for surgical ventricular restoration and/or restrictive mitral annuloplasty and 12 patients with normal LV function scheduled for coronary artery bypass grafting were included. PV signals were obtained before and after cardiac surgery by pressure-conductance catheters and gradual pre-load reductions by vena cava occlusion (VCO). The SB method was applied to the first beat of the VCO run. Accuracy was quantified by the root-mean-square-error (RMSE) between ESPVR(SB) and gold-standard ESPVR(VCO). In addition, we compared slopes (E(ES)) and intercepts (end-systolic volume at multiple pressure levels (70-100 mmHg: ESV(70)-ESV(100)) of ESPVR(SB) vs. ESPVR(VCO) by Bland-Altman analyses.

RESULTS

RMSE was 1.7 + or - 1.0 mmHg and was not significantly different between groups and not dependent on end-diastolic volume, indicating equal, high accuracy over a wide volume range. SB-predicted E(ES) had a bias of -0.39 mmHg mL(-1) and limits of agreement (LoA) -2.0 to +1.2 mmHg mL(-1). SB-predicted ESVs at each pressure level showed small bias (range: -10.8 to +9.4 mL) and narrow LoA. Two-way anova indicated that differences between groups were not dependent on the method.

CONCLUSION

Our findings, obtained in hearts spanning a wide range of sizes and conditions, support the use of the SB method. This method ultimately facilitates less invasive ESPVR estimation, particularly when coupled with emerging noninvasive techniques to measure LV pressures and volumes.

Arterial load and ventricular-arterial coupling: physiologic relations with body size and effect of obesity

Accurate quantification of arterial function is crucial to distinguishing disease states from normal variants. However, there are little data regarding methods to scale arterial load to body size in humans. We studied 2365 adults aged 35 to 55 years free of overt cardiovascular disease. We assessed arterial hemodynamics and ventricular-vascular coupling with carotid tonometry and Doppler echocardiography. To define normal (physiological) relationships between hemodynamic indices and body size, we used nonlinear regression to analyze a selected reference subsample (n=612) with normal weight (body mass index 18 to 25 kg/m(2)), waist circumference, and metabolic parameters. Most arterial hemodynamic indices demonstrated important relationships with body size, which were frequently allometric (nonlinear). Allometric indexation using appropriate powers (but not ratiometric indexation) effectively eliminated the relationships between indices of arterial load and body size in normal subjects. In the entire sample (n=2365), the adverse effects of obesity on arterial load and end-systolic ventricular stiffening were clearly demonstrated only after appropriate indexation to account for the expected normal relationship to body size. After adjustment for age and sex, a progressive increase in indexed systemic vascular resistance, effective arterial and ventricular end-systolic elastance, and a decrease in total arterial compliance were seen from normal weight to obesity (P<0.0001). Arterial load relates to body size in an allometric fashion, calling for scaling with the use of appropriate powers. Obesity exerts adverse effects on arterial load and ventricular stiffening that go beyond the normal relationship with body size. Allometric normalization should allow more accurate quantification of arterial load in future studies.

Arterial-ventricular coupling: mechanistic insights into cardiovascular performance at rest and during exercise

Understanding the performance of the left ventricle (LV) requires not only examining the properties of the LV itself, but also investigating the modulating effects of the arterial system on left ventricular performance. The interaction of the LV with the arterial system, termed arterial-ventricular coupling (E(A)/E(LV)), is a central determinant of cardiovascular performance and cardiac energetics. E(A)/E(LV) can be indexed by the ratio of effective arterial elastance (E(A); a measure of the net arterial load exerted on the left ventricle) to left ventricular end-systolic elastance (E(LV); a load-independent measure of left ventricular chamber performance). At rest, in healthy individuals, E(A)/E(LV) is maintained within a narrow range, which allows the cardiovascular system to optimize energetic efficiency at the expense of mechanical efficacy. During exercise, an acute mismatch between the arterial and ventricular systems occurs, due to a disproportionate increase in E(LV) (from an average of 4.3 to 13.2, and 4.7 to 15.5 mmHg.ml(-1).m(-2) in men and women, respectively) vs. E(A) (from an average of 2.3 to 3.2, and 2.3 to 2.9 mmHg.ml(-1).m(-2) in men and women, respectively), to ensure that sufficient cardiac performance is achieved to meet the increased energetic requirements of the body. As a result E(A)/E(LV) decreases from an average of 0.58 to 0.34, and 0.52 to 0.27 in men and women, respectively. In this review, we provide an overview of the concept of E(A)/E(LV), and examine the effects of age, hypertension, and heart failure on E(A)/E(LV) and its components (E(A) and E(LV)) in men and women. We discuss these effects both at rest and during exercise and highlight the mechanistic insights that can be derived from studying E(A)/E(LV).

The sex-specific impact of systolic hypertension and systolic blood pressure on arterial-ventricular coupling at rest and during exercise

In healthy subjects the arterial system and the left ventricle (LV) are tightly coupled at rest to optimize cardiac performance. Systolic hypertension (SH) is a major risk factor for heart failure and is associated with structural and functional alterations in the arteries and the LV. The effects of SH and resting systolic blood pressure (SBP) on arterial-ventricular coupling (E(a)I/E(LV)I) at rest, at peak exercise, and during recovery are not well described. We noninvasively characterized E(a)I/E(LV)I as end-systolic volume index/stroke volume index in subjects who were normotensive (NT, n = 203) or had SH (brachial SBP > or =140 mmHg, n = 79). Cardiac volumes were measured at rest and throughout exhaustive upright cycle exercise with gated blood pool scans. E(a)I/E(LV)I reserve was calculated by subtracting peak from resting E(a)I/E(LV)I. At rest, E(a)I/E(LV)I did not differ between SH and NT men but was 23% (P = 0.001) lower in SH vs. NT women. E(a)I/E(LV)I did not differ between SH and NT men or women at peak exercise or during recovery. Nevertheless, E(a)I/E(LV)I reserve was 61% (P < 0.001) lower in SH vs. NT women. Similarly, resting SBP (as a continuous variable) was not associated with E(a)I/E(LV)I in men (beta = -0.12, P = 0.17) but was inversely associated with E(a)I/E(LV)I in women (beta = -0.47, P < 0.001). SH and a higher resting brachial SBP are associated with a lower E(a)I/E(LV)I at rest in women but not in men, and SH women have an attenuated E(a)I/E(LV)I reserve. Whether a smaller E(a)I/E(LV)I reserve leads to functional limitations warrants further examination.

Negative stress echo: Further prognostic stratification with assessment of pressure–volume relation

BACKGROUND

A maximal negative stress echo identifies a low risk for subsequent hard events subset. However, the potentially prognostically relevant information on global contractile reserve on the left ventricle is missed by standard regional wall motion assessment, and can be obtained by end-systolic pressure-volume relationship (PVR) evaluation.

AIM

To assess the relative prognostic value of PVR in patients with negative stress echo.

METHODS

We enrolled 99 consecutive patients (age=61+/-14 years; 81 males, LVEF 47+/-14%, WMSI=1.42+/-0.50) with negative exercise stress echo for standard wall motion criteria. To build the PVR, the force was determined at rest and peak stress as the ratio of the systolic pressure/end-systolic volume index. All patients were followed-up on medical therapy.

RESULTS

Median follow-up was 21 months (interquartile range 12-26). Twenty-nine events have been observed: 6 deaths, 10 heart failure related hospitalization and 13 worsening NYHA class of >or=1 grade. Using Cox's proportional hazard model the best independent predictor of total events was SP/ESV index change (rest-stress) <1.5 mm Hg/ml/m(2) as determined by ROC analysis cut-off (RR=29, p=0.001, sensitivity=80%, specificity=93%). The overall survival and event-free survival was 34% in patients with change (rest-stress) SP/ESV index<1.5 mm Hg/ml/m(2) and 97% in whose with >1.5 mm Hg/ml/m(2).

CONCLUSIONS

In patients with negative stress echo, a preserved global contractility response can be easily identified through stress-induced variation in SP/ESV index, with powerful further risk stratification.

Arterial Stiffness Is Associated With Regional Ventricular Systolic and Diastolic Dysfunction

Objective— The pathophysiology of left ventricular (LV) dysfunction, particularly in the setting of a preserved ejection fraction (EF), remains unclear. Few studies have investigated the relationship between arterial compliance and LV function in humans, and none used cardiovascular MRI.

Methods and Results— We sought to determine whether arterial compliance is related to regional myocardial function among participants of the Multi-Ethnic Study of Atherosclerosis (MESA). Arterial compliance was assessed using carotid ultrasound measurements to calculate the distensibility coefficient (DC) and Young’s modulus (YM). Circumferential systolic (SR S ) and diastolic (SR E ) strain rates were calculated by harmonic phase (HARP) from tagged MRI. Associations between arterial compliance and indices of ventricular function were adjusted for cardiovascular risk factors. We found a significant association between arterial compliance and SR S in all myocardial regions ( P <0.05); arterial compliance was also associated with SR E in the lateral and septal wall regions ( P <0.05). Multiple linear regression analyses demonstrated a direct linear relationship between the carotid artery DC and SR S across all LV segments and slices, even after adjustment for cardiovascular risk factors and LV mass. In regression analyses, a significant relationship between arterial compliance and SR E in the septal and antero-apical walls was also found and remained significant after multivariable adjustment.

Conclusion— Arterial stiffness is associated with early and asymptomatic impairment of systolic as well as diastolic myocardial function. Further studies are needed to elucidate role of vascular compliance in the development of ventricular dysfunction and failure.

Relation of Proximal Aorta Stiffness to Left Ventricular Diastolic Function in Patients with End-Stage Renal Disease

AIM

We examined the relationship between proximal aortic stiffness and left ventricular (LV) diastolic function in patients with end-stage renal disease (ESRD).

PATIENTS AND METHODS

We studied 99 patients with ESRD with preserved LV ejection fraction greater than 50% and 83 controls. We assessed the aorta stiffness by measuring the pulse wave velocity (PWV) in the proximal aorta (PWVr) using a novel echo application and in the descending aorta (PWVcf) using a foot-to-foot method. Patients were classified according to LV diastolic filling pattern into normal, delayed relaxation, pseudonormal, and restrictive filing pattern groups.

RESULTS

Patients with ESRD had increased PWVr, PWVcf, and LV mass index (LVMI) compared with controls (all P < .0001). Patients with advanced diastolic dysfunction showed increased PWVr (P < .001) and PWVcf (P = .007) compared with those with mild diastolic dysfunction. PWVr was correlated to PWVcf (r = 0.74, P < .001) in patients with ESRD. Multivariate linear regression analysis revealed that PWVr was independently correlated to both LVMI and LV diastolic filling pattern.

CONCLUSIONS

Increased LVMI, advanced LV diastolic dysfunction, and generalized aortic stiffening were observed in patients with ESRD. Proximal aorta stiffness is associated with both increased LVMI and advanced LV diastolic dysfunction in those patients.

Ventricular-arterial and ventricular-ventricular interactions and their relevance to diastolic filling

Chronic heart failure is a common clinical problem, and, until recently, attention has focused predominantly on those patients with reduced left ventricular (LV) systolic function, as evidenced by a reduced LV ejection fraction. However, nearly half of all patients thought clinically to have heart failure have a "preserved" LV ejection fraction, variously defined as greater than 40% to 45% ("heart failure with normal ejection fraction" syndrome). The interaction of the heart with the systemic vasculature, termed ventricular-arterial coupling, is a key determinant of cardiovascular performance. The capacity of the body to augment cardiac output, regulate systemic blood pressure, and respond appropriately to elevations in heart rate and preload depends on both the properties of the heart and the properties of the vasculature into which the heart ejects blood. Although the marked increase of arterial and cardiac stiffness with aging can maintain ventricular-vascular coupling within a normal range, it does have detrimental effects on hemodynamic stability and cardiac reserve. Patients with heart failure with normal ejection fraction have been shown to have both arterial and ventricular stiffening, resulting in enhanced pressure-load dependence and sensitivity of blood pressure to circulating volume and diuretics. There is also indirect evidence to suggest that on exercise, increased external constraint to LV filling (as a result of diastolic ventricular interaction and pericardial constraint) may contribute to impaired use of the Starling mechanism in this group of patients.

Age-specific relationship of aortic pulse wave velocity with left ventricular geometry and function in hypertension

Aortic pulse wave velocity (PWV), generally considered an intrinsic marker of arterial stiffness, might depend in part on the velocity of myocardial fiber shortening, but the relation between PWV and myocardial function in humans has been understudied. A total of 237 untreated hypertensive subjects over a wide age range (18 to 88 years) underwent aortic PWV determination and echocardiography, from which the mean velocity of circumferential fiber shortening was calculated as a measure of the velocity of myocardial shortening, and relative wall thickness was taken as a measure of left ventricular concentric remodeling. Patients were divided in 3 age groups (<40 years, 40 to 59 years, and >or=60 years). In the young, aortic PWV was directly associated with heart rate-corrected velocity of circumferential fiber shortening (r=0.39; P=0.002) but not to relative wall thickness (r=-0.01; P=0.95). The opposite was found in the older group, in which aortic PWV was accompanied by a concentric left ventricular geometric pattern (r=0.44 with relative wall thickness; P=0.009) and a reduced velocity of circumferential fiber shortening (r=-0.54; P<0.001) and stress-corrected midwall fractional shortening (r=-0.56; P<0.001). Intermediate values were found in the middle-aged group (r=0.23; P<0.01 with relative wall thickness; r=-0.07, P value not significant with velocity of circumferential fiber shortening). In conclusion, the relation between aortic PVW and the left ventricle is strongly age dependent. These data suggest that, in young people, aortic PWV is partly determined by an increased velocity of myocardial shortening. With increasing age, a relationship between aortic PWV (as a measure of arterial stiffness) and left ventricular concentric geometry emerges, which ultimately leads to a depressed ventricular systolic function.

Left ventricular geometry and mortality in patients >70 years of age with normal ejection fraction

Numerous studies have indicated that left ventricular (LV) hypertrophy predicts morbidity and mortality, including studies in older patients. The prognostic impact of other LV geometric patterns, including concentric remodeling (CR), compared with LV hypertrophy has not been studied in a large cohort of older patients. Echocardiographic and clinical data were studied in 9,771 consecutive patients aged >70 years with ejection fractions > or =50% who were followed for 3.1 years to determine the impact of LV geometric patterns. CR was the most prevalent pattern (43%), and 16% met criteria for LV hypertrophy. Although patients with CR had significantly lower LV mass indexes than patients with normal structure as well as those with LV hypertrophy, their mortality was 35% higher than that of normal subjects (15.5% vs 11.5%, p <0.0001) and 13% higher than that of patients with eccentric LV hypertrophy (15.5% vs 13.7%, p <0.001) with similar mortality to those with concentric LV hypertrophy (15.5% vs 15.9%). In conclusion, abnormal LV geometry is extremely common in patients aged >70 years with normal systolic function, being present in 59% of this population, with CR (43%) by far the most common LV geometric pattern. Patients aged >70 years with CR have significantly increased mortality compared with similarly aged patients with either normal structure or eccentric LV hypertrophy, with similar increased mortality to those with concentric LV hypertrophy.

Comparison of cardiac and peripheral arterial stiffening and ventriculovascular uncoupling in patients with uncomplicated hypertension versus patients with hypertension after heart transplantation

Despite normal ejection fractions, patients who undergo heart transplantation (HT) have low peak aerobic capacity and reduced arterial compliance, suggesting "ventriculovascular uncoupling." To what extent this is related to post-transplantation hypertension versus the unique characteristics of the donor-recipient relation remains poorly understood. Echocardiograms were retrospectively reviewed from 126 normal subjects, 309 patients with uncomplicated hypertension (UH), and 58 consecutive patients with HT >1 year after the procedure who were stable without evidence of rejection. Left ventricular (LV) end-systolic elastance (Ees), a measure of LV systolic performance; effective arterial elastance (Ea), a measure of vascular stiffness; and Ea/Ees, a parameter describing ventriculovascular coupling, were obtained. Compared with normal subjects, tandem increases in Ea (+24% and +85%, all p values <0.0001) and Ees (+23% and +33%, all p values <0.0001) were observed in patients with UH and HT, respectively, with patients with HT having significantly higher values than those with UH (both p values <0.05). Although the Ea/Ees ratio remained similar between normal subjects and patients with UH, patients with HT exhibited increases in the Ea/Ees ratio (all p values <0.01) and reduced stroke volume indexes (-20% and -22%, respectively, all p values <0.05). These changes were associated with a doubling of LV concentric remodeling in patients with HT compared with those with UH (67% vs 34%, p <0.0001). In conclusion, HT is associated with increases in Ees, Ea, and the Ea/Ees ratio, suggesting ventriculovascular uncoupling and maximal LV stroke work. These aberrations, which determine cardiovascular performance in the setting of HT, are not simply explained by vascular age or post-transplantation hypertension but may adversely affect functional capacity.

Ventricular-arterial coupling in a rat model of reduced arterial compliance provoked by hypervitaminosis D and nicotine

The vitamin D(3) and nicotine (VDN) model is one of isolated systolic hypertension (ISH) in which arterial calcification raises arterial stiffness and vascular impedance. The effects of VDN treatment on arterial and cardiac hemodynamics have been investigated; however, a complete analysis of ventricular-arterial interaction is lacking. Wistar rats were treated with VDN (VDN group, n = 9), and a control group (n = 10) was included without the VDN. At week 8, invasive indexes of cardiac function were obtained using a conductance catheter. Simultaneously, aortic pressure and flow were measured to derive vascular impedance and characterize ventricular-vascular interaction. VDN caused significant increases in systolic (138 +/- 6 vs. 116 +/- 13 mmHg, P < 0.01) and pulse (42 +/- 10 vs. 26 +/- 4 mmHg, P < 0.01) pressures with respect to control. Total arterial compliance decreased (0.12 +/- 0.08 vs. 0.21 +/- 0.04 ml/mmHg in control, P < 0.05), and pulse wave velocity increased significantly (8.8 +/- 2.5 vs. 5.1 +/- 2.0 m/s in control, P < 0.05). The arterial elastance and end-systolic elastance rose significantly in the VDN group (P < 0.05). Wave reflection was augmented in the VDN group, as reflected by the increase in the wave reflection coefficient (0.63 +/- 0.06 vs. 0.52 +/- 0.05 in control, P < 0.05) and the amplitude of the reflected pressure wave (13.3 +/- 3.1 vs. 8.4 +/- 1.0 mmHg in control, P < 0.05). We studied ventricular-arterial coupling in a VDN-induced rat model of reduced arterial compliance. The VDN treatment led to development of ISH and provoked alterations in cardiac function, arterial impedance, arterial function, and ventricular-arterial interaction, which in many aspects are similar to effects of an aged and stiffened arterial tree.

Ventriculovascular coupling in systolic and diastolic heart failure

Pressure-volume analysis has provided critical insight into ventricular mechanics, and it has elucidated the underlying mechanisms of heart failure (HF). Renewed interest in ventriculovascular coupling, the interaction of the left ventricle and the arterial system, has developed from recent investigations focusing on the importance of heart rate control in systolic HF, blood pressure lability in the elderly, and acute pulmonary edema in patients with HF and a normal ejection fraction. These data suggest that abnormal ventriculovascular coupling may be an additional pathophysiologic mechanism underlying the development of HF with a normal ejection fraction and may provide a target for novel therapies.

Left ventricular geometry and survival in patients with normal left ventricular ejection fraction

In hypertensive populations, left ventricular (LV) geometry, which is characterized by hypertrophy, predicts cardiovascular outcome. The left ventricle can also alter its shape by concentric remodeling (CR) in the absence of LV hypertrophy, a feature that is detected by echocardiography. This study assessed the prevalence and prognostic significance of various forms of LV geometry and changes in LV geometry over time in patients with normal LV systolic function. Retrospective analysis of a large clinical population (n = 35,602) that was referred for echocardiography was done, with all-cause mortality as the primary outcome. Abnormal LV geometry was identified in 46% of patients, with CR present in 35% (n = 12,362) and LV hypertrophy in 11% (n = 3,958). Patients with abnormal LV geometry were older and more obese compared with subjects with normal LV geometry. There was a strong relation between abnormal LV geometry and mortality, and patients with CR and LV hypertrophy exhibited considerably higher relative risk for all-cause mortality compared with subjects with normal LV geometry (relative risk [RR] 1.99, 95% confidence interval [CI] 1.88 to 2.18, p <0.0001; RR 2.13, 95% CI 1.89 to 2.40, p <0.0001, respectively). Subjects with CR who reverted to a normal geometric pattern had improved survival (RR 0.64, 95% CI 0.42 to 0.97, p = 0.03) compared with those who progressed to LV hypertrophy (RR 1.54, 95% CI 1.01 to 2.47, p = 0.05). In conclusion, CR, a form of cardiac adaptation, is frequently noted in patients with normal LV ejection fractions and confers a risk of death similar to that of LV hypertrophy. Normalization of CR is associated with better survival, whereas transition to LV hypertrophy increases mortality.

Ventriculovascular coupling in systolic and diastolic heart failure

Pressure-volume analysis has provided critical insight into ventricular mechanics, and it has elucidated the underlying mechanisms of heart failure (HF). Renewed interest in ventriculovascular coupling, the interaction of the left ventricle and the arterial system, has developed from recent investigations focusing on the importance of heart rate control in systolic HF, blood pressure lability in the elderly, and acute pulmonary edema in patients with HF and a normal ejection fraction. These data suggest that abnormal ventriculovascular coupling may be an additional pathophysiological mechanism underlying the development of HF with a normal ejection fraction and may provide a target for novel therapies.

Age- and gender-related ventricular-vascular stiffening: a community-based study

BACKGROUND

Increases in vascular (Ea), ventricular systolic (Ees), and ventricular diastolic (Ed) elastance (stiffness) may contribute to the pathogenesis of heart failure (HF) with preserved ejection fraction (HFnlEF). The prevalence of HFnlEF increases strikingly with age, particularly in women. We hypothesized that ventricular-vascular stiffening may occur with age and be more pronounced in women in the general community.

METHODS AND RESULTS

In a cross-sectional sample of Olmsted County, Minn, residents > or =45 years old (n=2042), clinical data, Doppler echocardiography, and blood pressure (BP) measurements were obtained. Ea was calculated from stroke volume and systolic BP and indexed to body size (EaI). Ees was calculated by a modified single-beat method using systolic and diastolic BP, stroke volume, ejection fraction, timing intervals, and an estimated normalized ventricular elastance at arterial end diastole. Operant Ed was calculated from Doppler indices reflective of atrial pressures and the diastolic filling volume. EaI, Ees, and Ed all increased with age in men and in women (P<0.0001 for all). Ees increased more steeply with age in women (P=0.002). Adjusted for age, EaI, Ees, and Ed were higher in women than in men (P<0.0001 for all). Findings were similar in those without known or suspected cardiovascular disease (n=623).

CONCLUSIONS

In the community, advancing age and female gender are associated with increases in vascular and ventricular systolic and diastolic stiffness even in the absence of cardiovascular disease. We speculate that this combined ventricular-vascular stiffening may contribute to the increased prevalence of HFnlEF in elderly persons and particularly in elderly women.

Age and gender affect ventricular-vascular coupling during aerobic exercise

OBJECTIVES

The goal of this study was to examine the age-associated differences in ventricular-vascular coupling, defined by the ratio of arterial elastance (EaI) to left ventricular systolic elastance (E(LV)I), and its components, at rest and during exercise.

BACKGROUND

Ejection fraction (EF) increases during exercise, but the EF reserve decreases with aging. Ejection fraction is inversely related to EaI/E(LV)I, an index of the interaction between arterial and ventricular properties, which is an important determinant of cardiac performance. Thus, age differences in EaI/E(LV)I during exercise, due to age differences in EaI, E(LV)I, or both, may help to explain the age deficit in EF reserve.

METHODS

We noninvasively characterized EaI/E(LV)I = end-systolic volume index (ESVI)/stroke volume index (SVI) and its two determinants EaI = end-systolic pressure/SVI, and E(LV)I = end-systolic pressure/ESVI, at rest and during exercise in 239 healthy men and women (age range, 21 to 87 years). Blood pressures were assessed with cuff sphygomanometry, and cardiac volumes with gated blood pool scintingraphy.

RESULTS

Resting EaI/E(LV)I was not age related in men or women. In both sexes, EaI/E(LV)I decreased during exercise and declined to a lesser extent in older subjects. There were gender differences in the components of EaI/E(LV)I during exercise: EaI was greater in older versus young women (p = 0.01) but was unaffected by age in men. Left ventricular systolic elastance increased to a greater extent in young versus older subjects (p = 0.0001 for men, p = 0.07 for women).

CONCLUSIONS

Age-associated differences in EaI/E(LV)I occur in both genders during exercise. Sub-optimal ventricular-vascular coupling helps to explain the age-associated blunting of maximal exercise EF, and its underlying mechanisms appear to differ between men and women.

Differences in left ventricular structure between black and white hypertensive adults: the Hypertension Genetic Epidemiology Network study

The degree to which ethnic differences in left ventricular structure among hypertensive adults are independent of clinical and hemodynamic factors remains uncertain. We assessed whether left ventricular mass and geometry differ between black and white hypertensives after accounting for differences in such factors. Our study group comprised 1060 black and 580 white hypertensive participants free of valvular or coronary disease in a population-based cohort. Blood pressure was measured during a clinic visit and echocardiography was performed using standardized protocols. After controlling for clinical and hemodynamic parameters (cardiac index, peripheral resistance index, and pulse pressure/stroke index), both left ventricular mass and relative wall thickness were higher in blacks than whites (173.9+/-30.9 versus 168.3+/-24.3 grams, P=0.006, and 0.355+/-0.055 versus 0.340+/-0.055 grams, P<0.001). Similarly, the adjusted risk of having left ventricular hypertrophy, whether indexed by height(2.7) or by body surface area, was greater for blacks than for whites (odds ratio: 1.80; 95% CI: 1.29 to 2.51; and odds ratio: 2.50; 95% CI: 1.58 to 3.96, respectively), and this was also true for concentric geometry (odds ratio: 2.28; 95% CI: 1.22 to 4.25). Further adjustment for relatedness in this genetic epidemiological study did not attenuate these differences. Our findings confirm the strong association between black ethnicity and increased left ventricular mass and relative wall thickness in hypertensive adults and demonstrate that these differences are independent of standard clinical and hemodynamic parameters. Whether such differences relate to distinct ambulatory pressure profiles or an ethnic propensity to cardiac hypertrophy requires further investigation.

Relationship between exercise systolic blood pressure and left ventricular geometry in overweight, mildly hypertensive patients

OBJECTIVE

To examine the association between the graded exercise systolic blood pressure (SBP) response and left ventricular (LV) geometric structure in patients with untreated mild hypertension.

PARTICIPANTS

The study included 80 sedentary, overweight patients (43 female and 37 male) with unmedicated high normal blood pressure or stage 1-2 hypertension.

METHODS

An echocardiogram was used to determine LV mass and the relative wall thickness (RWT) in relation to the chamber dimension. Participants performed a maximal graded exercise test, and the SBP was recorded at workloads of 2, 4 and 6 metabolic equivalents and at peak exercise. Separate statistical models were used to determine the influence of LV mass indexed for height(2.7) (LVMIh) and RWT on submaximal exercise SBP and peak exercise SBP, controlling for resting SBP, age, gender, ethnicity and body mass index.

RESULTS

A greater RWT was associated with a higher submaximal SBP level (P = 0.038). Neither LVMIh (P = 0.989) nor the interaction of RWT and LVMIh (P = 0.787) were related to the submaximal SBP. None of the main or interaction effects of RWT and LVMIh were associated with the peak exercise SBP level.

CONCLUSION

Increases in RWT were associated with higher submaximal exercise SBP responses in a sample of overweight, unmedicated hypertensives. These results suggest that RWT is an important determinant of the association between cardiac mass and exercise SBP response.