Relation of impaired left ventricular filling to systolic midwall mechanics in hypertensive patients with normal left ventricular systolic chamber function: the Losartan Intervention for Endpoint Reduction in Hypertension (LIFE) study

Early-stage heart failure with preserved ejection fraction in the pig: a cardiovascular magnetic resonance study

BACKGROUND

The hypertensive deoxy-corticosterone acetate (DOCA)-salt-treated pig (hereafter, DOCA pig) was recently introduced as large animal model for early-stage heart failure with preserved ejection fraction (HFpEF). The aim of the present study was to evaluate cardiovascular magnetic resonance (CMR) of DOCA pigs and weight-matched control pigs to characterize ventricular, atrial and myocardial structure and function of this phenotype model.

METHODS

Five anesthetized DOCA and seven control pigs underwent 3 T CMR at rest and during dobutamine stress. Left ventricular/atrial (LV/LA) function and myocardial mass (LVMM), strains and torsion were evaluated from (tagged) cine imaging. 4D phase-contrast measurements were used to assess blood flow and peak velocities, including transmitral early-diastolic (E) and myocardial tissue (E') velocities and coronary sinus blood flow. Myocardial perfusion reserve was estimated from stress-to-rest time-averaged coronary sinus flow. Global native myocardial T1 times were derived from prototype modified Look-Locker inversion-recovery (MOLLI) short-axis T1 maps. After in-vivo measurements, transmural biopsies were collected for stereological evaluation including the volume fractions of interstitium (V_V(int/LV)) and collagen (V_V(coll/LV)). Rest, stress, and stress-to-rest differences of cardiac and myocardial parameters in DOCA and control animals were compared by t-test.

RESULTS

In DOCA pigs LVMM (p < 0.001) and LV wall-thickness (end-systole/end-diastole, p = 0.003/p = 0.007) were elevated. During stress, increase of LV ejection-fraction and decrease of end-systolic volume accounted for normal contractility reserves in DOCA and control pigs. Rest-to-stress differences of cardiac index (p = 0.040) and end-diastolic volume (p = 0.042) were documented. Maximal (p = 0.042) and minimal (p = 0.012) LA volumes in DOCA pigs were elevated at rest; total LA ejection-fraction decreased during stress (p = 0.006). E' was lower in DOCA pigs, corresponding to higher E/E' at rest (p = 0.013) and stress (p = 0.026). Myocardial perfusion reserve was reduced in DOCA pigs (p = 0.031). T1-times and V_V(int/LV) did not differ between groups, whereas V_V(coll/LV) levels were higher in DOCA pigs (p = 0.044).

CONCLUSIONS

LA enlargement, E' and E/E' were the markers that showed the most pronounced differences between DOCA and control pigs at rest. Inadequate increase of myocardial perfusion reserve during stress might represent a metrics for early-stage HFpEF. Myocardial T1 mapping could not detect elevated levels of myocardial collagen in this model.

TRIAL REGISTRATION

The study was approved by the local Bioethics Committee of Vienna, Austria (BMWF-66.010/0091-II/3b/2013).

Early-stage heart failure with preserved ejection fraction in the pig: a cardiovascular magnetic resonance study

BACKGROUND

The hypertensive deoxy-corticosterone acetate (DOCA)-salt-treated pig (hereafter, DOCA pig) was recently introduced as large animal model for early-stage heart failure with preserved ejection fraction (HFpEF). The aim of the present study was to evaluate cardiovascular magnetic resonance (CMR) of DOCA pigs and weight-matched control pigs to characterize ventricular, atrial and myocardial structure and function of this phenotype model.

METHODS

Five anesthetized DOCA and seven control pigs underwent 3 T CMR at rest and during dobutamine stress. Left ventricular/atrial (LV/LA) function and myocardial mass (LVMM), strains and torsion were evaluated from (tagged) cine imaging. 4D phase-contrast measurements were used to assess blood flow and peak velocities, including transmitral early-diastolic (E) and myocardial tissue (E') velocities and coronary sinus blood flow. Myocardial perfusion reserve was estimated from stress-to-rest time-averaged coronary sinus flow. Global native myocardial T1 times were derived from prototype modified Look-Locker inversion-recovery (MOLLI) short-axis T1 maps. After in-vivo measurements, transmural biopsies were collected for stereological evaluation including the volume fractions of interstitium (VV(int/LV)) and collagen (VV(coll/LV)). Rest, stress, and stress-to-rest differences of cardiac and myocardial parameters in DOCA and control animals were compared by t-test.

RESULTS

In DOCA pigs LVMM (p < 0.001) and LV wall-thickness (end-systole/end-diastole, p = 0.003/p = 0.007) were elevated. During stress, increase of LV ejection-fraction and decrease of end-systolic volume accounted for normal contractility reserves in DOCA and control pigs. Rest-to-stress differences of cardiac index (p = 0.040) and end-diastolic volume (p = 0.042) were documented. Maximal (p = 0.042) and minimal (p = 0.012) LA volumes in DOCA pigs were elevated at rest; total LA ejection-fraction decreased during stress (p = 0.006). E' was lower in DOCA pigs, corresponding to higher E/E' at rest (p = 0.013) and stress (p = 0.026). Myocardial perfusion reserve was reduced in DOCA pigs (p = 0.031). T1-times and VV(int/LV) did not differ between groups, whereas VV(coll/LV) levels were higher in DOCA pigs (p = 0.044).

CONCLUSIONS

LA enlargement, E' and E/E' were the markers that showed the most pronounced differences between DOCA and control pigs at rest. Inadequate increase of myocardial perfusion reserve during stress might represent a metrics for early-stage HFpEF. Myocardial T1 mapping could not detect elevated levels of myocardial collagen in this model.

TRIAL REGISTRATION

The study was approved by the local Bioethics Committee of Vienna, Austria (BMWF-66.010/0091-II/3b/2013).

Usefulness of speckle tracking echocardiography in hypertensive crisis and the effect of medical treatment

The acute impact of hypertensive crisis, and changes after treatment, on left ventricular (LV) systolic and diastolic function using comprehensive echocardiography, including speckle tracking, has not been well characterized. Thirty consecutive patients admitted to the hospital from the emergency room with hypertensive crisis underwent Doppler echocardiography at baseline and after blood pressure optimization. The mean age of the patients was 54 ± 13 years, with 19 men (63%). The most common presenting symptoms included dyspnea (70%), chest pain (43%), and altered mental status (13%). Mean systolic and diastolic blood pressures at presentation were 198 ± 12 and 122 ± 12 mm Hg, decreasing to 143 ± 15 and 77 ± 12 mm Hg (p <0.001 for both) after treatment. There was no significant change in LV ejection fraction between baseline and follow-up (48 ± 18% vs 46 ± 18%, p = 0.50); however, global longitudinal LV systolic strain (-10 ± 4% to -12 ± 4%, p = 0.01) and global systolic strain rate (-1.0 ± 0.4 vs -1.4 ± 0.6 s(-1), p = 0.01) significantly improved. Mean global early diastolic strain (-7.2 ± 4.0% to -9.4 ± 2.9%, p = 0.004) and early diastolic strain rate (0.3 ± 0.2 to 0.5 ± 0.4 s(-1), p = 0.05) also improved after treatment. On multivariate analysis, the independent predictors of LV longitudinal strain at follow-up were LV ejection fraction (p <0.001), heart rate (p = 0.005), systolic blood pressure (p = 0.04), and left atrial volume index (p = 0.05). In conclusion, as opposed to LV ejection fraction, LV systolic strain and strain rate were depressed during hypertensive crisis and significantly improved after medical treatment. LV diastolic function, assessed using conventional and speckle-tracking parameters, was also depressed and significantly improved after treatment.

Diagnosis and management of left ventricular diastolic dysfunction in the hypertensive patient

The progression of hypertensive involvement toward heart failure includes myocardial fibrosis and changes of left ventricular (LV) geometry. In the presence of these abnormalities, diastolic abnormalities occur and are defined as LV diastolic dysfunction (DD). They include alterations of both relaxation and filling, precede alterations of chamber systolic function and can induce symptoms of heart failure even when ejection fraction is normal. The prevalence of heart failure with normal ejection fraction (HFNEF) increased over time whereas the rate of death from this disorder remained unchanged. In this view, diagnosis, prognosis, and therapeutic management of DD and HFNEF in hypertensive patients is a growing public health problem. DD may be asymptomatic and identified occasionally during a Doppler-echocardiographic examination. This tool has gained, therefore, important clinical position for diagnosis of DD. Comprehensive assessment of diastolic function should be done not by a simple classification of DD progression but by estimating the degree of LV filling pressure (FP), a true determinant of symptoms and prognosis. This can be obtained by different ultrasound maneuvers/tools but the ratio between transmitral E velocity and pulsed tissue Doppler-derived early diastolic velocity (E/e' ratio) is the most feasible and accurate. The identification of left atrial enlargement may be useful in uncertain cases. The recommended management of DD in hypertensive patients should correspond to blood pressure (BP) lowering and to the attempt of reducing LV mass and normalizing LV geometry. Prospective studies with well-defined entry criteria are needed to establish whether this approach could reflect a better prognosis.

Prognostic significance of left ventricular diastolic dysfunction in patients with left ventricular hypertrophy and systemic hypertension (the LIFE Study)

Patients with hypertension and left ventricular (LV) hypertrophy commonly have impaired diastolic filling. However, it remains unknown whether changes in LV diastolic filling variables are associated with cardiovascular morbidity and mortality. In this study, 778 patients with hypertension with electrocardiographic LV hypertrophy who underwent echocardiography at baseline and annually thereafter during randomized losartan- or atenolol-based antihypertensive treatment were followed for a mean of 4.6 years. The composite cardiovascular end point was the first occurrence of fatal or nonfatal myocardial infarction, fatal or nonfatal stroke, and cardiovascular mortality. Antihypertensive therapy resulted in an increase in the prevalence of normal transmitral flow pattern from 28% to 46% of patients. Although antihypertensive treatment often resulted in a marked increase in the prevalence of normal mitral valve flow pattern, this was not associated with reduced cardiovascular morbidity and mortality when adjusting for blood pressure, left atrial diameter, LV mass index, and treatment in time-varying Cox analyses. In contrast, lower in-treatment E/A ratios and shorter mitral valve deceleration times were associated with less risk for heart failure. Similarly, normal in-treatment transmitral flow pattern was strongly associated with less risk for heart failure (hazard ratio 0.22, 95% confidence interval 0.05 to 0.98, p = 0.048), even when taking in-treatment left atrial diameter and blood pressure into account. In conclusion, antihypertensive treatment in patients with hypertension with electrocardiographic LV hypertrophy resulted in significant improvement in transmitral flow patterns; this was not associated with reduced cardiovascular morbidity and mortality. However, normal in-treatment LV filling was strongly associated with a reduced risk for hospitalization for heart failure.

Evaluation of systolic properties in hypertensive patients with different degrees of diastolic dysfunction and normal ejection fraction

BACKGROUND

Left ventricular (LV) diastolic dysfunction (DD) associated with a preserved ejection fraction (EF) is a frequent alteration in hypertensive patients, usually considered an impairment of the diastolic phase alone. However, because systole and diastole are strictly correlated to one another, it is possible that hypertensive patients with isolated DD may also present with initial abnormalities of LV systolic properties, particularly those presenting with a more severe degree of DD. We performed a multiparametric echocardiographic assessment of LV systolic properties in patients without cardiovascular diseases, with preserved EF and different degrees of DD.

METHODS

We evaluated 1,073 hypertensive subjects showing EF >55% and no overt heart disease.

RESULTS

A total of 362 patients had normal diastolic function (N), 609 displayed delayed relaxation pattern (DR), and 102 presented a pseudonormal filling pattern (PN). Albeit most of the subjects with DD (DR, PN) had systolic indexes within normal range, they presented a significant reduction of index stroke volume (SV) (P < 0.0001) and stroke work (SW) (P < 0.0001), EF (P < 0.01), midwall shortening (MFS) (P < 0.0001), circumferential end-systolic stress-corrected MFS (cESS-MFS) (P < 0.001), and tissue Doppler (TD) systolic velocity (P < 0.0001) as compared to the N group, particularly the PN group.After adjustments, the reductions of LV systolic indexes were still significantly related to DD, particularly to PN.

CONCLUSIONS

Our results suggest a relation between LV systolic and diastolic properties in patients with normal EF. They also highlight the early onset of a preclinical reduction of systolic properties in patients with "isolated" DD, which is related to the degree of dysfunction.

Treatment of hypertension in heart failure with preserved ejection fraction: role of the kidney

Heart failure can present clinically as primarily diastolic or systolic dysfunction or both. There is an increasing awareness that heart failure can occur in the presence of a normal left ventricular ejection fraction. Heart failure with normal left ventricular ejection fraction is frequently referred to as diastolic heart failure because of the presence of diastolic left ventricular dysfunction evident from impaired left ventricular relaxation. This article focuses on the treatment of hypertension and the role the kidney plays in selecting appropriate agents.

Independent association of coronary flow reserve with left ventricular relaxation and filling pressure in arterial hypertension

BACKGROUND

It has been recognized that "cross-talk" occurs between coronary flow and left ventricular (LV) function. This study tested the hypothesis that impairment of coronary flow reserve (CFR) in arterial hypertension is associated with LV systolic and diastolic dysfunction, independent of abnormalities in LV geometry.

METHODS

We studied 59 newly diagnosed, never-treated hypertensive patients, using transthoracic Doppler echocardiography including pulsed Tissue Doppler of mitral annulus and CFR on left anterior descending artery (low-dose dipyridamole). The study population was divided into two groups on the basis of age-normalized relative wall thickness (RWTn): 36 patients with normal LV geometry (RWTn < or = 0.41) and 23 patients with LV concentric geometry (RWTn > 0.41).

RESULTS

Patients with LV concentric geometry (RWTn > 0.41) had significantly lower values of midwall shortening (but not of endocardial shortening), longer isovolumic relaxation time (IVRT), lower Tissue Doppler-derived early diastolic velocity (Em), higher ratio of transmitral E velocity to Em, and lower CFR as compared to patients with normal LV geometry (RWTn < or = 0.41). In the whole population, a lower CFR was significantly associated with lower values of midwall shortening and Em, longer IVRT, and higher E/Em ratio. After controlling for heart rate, mean blood pressure, and RWTn, only the relation of CFR with IVRT, Em, and E/Em ratio remained significant.

CONCLUSIONS

Reduced midwall mechanics is associated with lower CFR, a relationship that depends on LV concentric geometry. A reduced CFR is associated with both impaired relaxation and increased filling pressure, a relation that is independent of LV geometry and pressure load.

The impact of hypertension on systolic and diastolic left ventricular function. A tissue Doppler echocardiographic study

BACKGROUND

The purpose of this study is to assess the impact of hypertension on systolic function and diastolic function using 2-dimensional echocardiography, conventional Doppler imaging of the transmitral inflow, and tissue Doppler imaging (TDI) of the mitral annulus.

METHODS

From an outpatient clinic population, 414 consecutive patients underwent 2-dimensional echocardiography, conventional Doppler imaging of the transmitral inflow, and TDI of the septal, lateral, inferior, and posterior walls near the mitral annulus. Parameters of systolic left ventricular (LV) function and diastolic LV function were assessed. Patients were divided according to the presence or absence of systemic hypertension (blood pressure > or = 140/90 mm Hg on > or = 3 measurements or treatment with antihypertensive medication).

RESULTS

A complete echocardiographic evaluation was obtained in 397 patients. Among these, 269 (68%) had hypertension. There was no difference with respect to age between patients with and without hypertension. Patients with hypertension had higher LV mass index and relative wall thickness and lower TDI peak systolic velocity (V(S)) when compared with patients without hypertension. In addition, indices of diastolic LV function were significantly impaired in hypertensive patients.

CONCLUSIONS

Quantitative echocardiography using TDI reveals that hypertensive patients with preserved global LV systolic function often have combined impairment of systolic function and diastolic function.