Aortic Regurgitation and Heart Failure: Advances in Diagnosis, Management, and Interventions

This review discusses the contemporary clinical evaluation and management of patients with comorbid aortic regurgitation (AR) and heart failure (HF) (AR-HF). Importantly, as clinical HF exists along the spectrum of AR severity, the present review also details novel strategies to detect early signs of HF before the clinical syndrome ensues. Indeed, there may be a vulnerable cohort of AR patients who benefit from early detection and management of HF. Additionally, while the mainstay of operative management for AR has historically been surgical aortic valve replacement, this review discusses alternate procedures that may be beneficial in high-risk cohorts.

Long-term outcomes after aortic valve surgery in patients with aortic regurgitation with preserved ejection fraction and left ventricular dilation

OBJECTIVES

This study aims to assess the long-term outcomes and prognostic predictors of asymptomatic patients with severe aortic regurgitation (AR) accompanied by left ventricular ejection fraction (LVEF) ≥ 55% and left ventricular end-diastolic diameter (LVEDD) > 65 mm undergoing aortic valve replacement (AVR).

METHODS

We retrospectively studied 291 consecutive asymptomatic patients with severe AR accompanied by LVEF ≥ 55% and LVEDD > 65 mm undergoing AVR from January 2000 to December 2013. The long-term outcomes and prognostic predictors were evaluated.

RESULTS

There were 2 (0.7%) in-hospital deaths caused by multiple organ failure. The overall survival rate was 95.2% at 5 years, 89.9% at 10 years, 85.9% at 15 years, and 85.9% at 20 years. The left ventricular end-systolic volume index (LVESVi) was an independent predictor of overall mortality, with 59 ml/m² being the best cut-off value. The left ventricular (LV) dimension decreased within 1 year after surgery and sustained thereafter. There were 15.5% of patients had incomplete LV reverse remodeling. LVESVi was an independent predictor of incomplete LV reverse remodeling, with 56 ml/m² being the best cut-off value.

CONCLUSIONS

AVR can be performed with an acceptable outcome in patients with severe AR accompanied by LVEF ≥ 55% and LVEDD > 65 mm. The LVESVi has the best predictive value for prognosis and the cut-off value is 59 ml/m², and has the best predictive value for incomplete LV reverse remodeling and the cut-off value is 56 ml/m².

Biventricular longitudinal strain as a predictor of functional improvement after D-shant device implantation in patients with heart failure

Background

The creation of an atrial shunt is a novel approach for the management of heart failure (HF), and there is a need for advanced methods for detection of cardiac function response to an interatrial shunt device. Ventricular longitudinal strain is a more sensitive marker of cardiac function than conventional echocardiographic parameters, but data on the value of longitudinal strain as a predictor of improvement in cardiac function after implantation of an interatrial shunt device are scarce. We aimed to investigate the exploratory efficacy of the D-Shant device for interatrial shunting in treating heart failure with reduced ejection fraction (HFrEF) and heart failure with preserved ejection fraction (HFpEF), and to explore the predictive value of biventricular longitudinal strain for functional improvement in such patients.

Methods

A total of 34 patients were enrolled (25 with HFrEF and 9 with HFpEF). All patients underwent conventional echocardiography and two-dimensional speckle tracking echocardiogram (2D-STE) at baseline and 6 months after implantation of a D-Shant device (WeiKe Medical Inc., WuHan, CN). Left ventricular global longitudinal strain (LVGLS) and right ventricular free wall longitudinal strain (RVFWLS) were evaluated by 2D-STE.

Results

The D-Shant device was successfully implanted in all cases without periprocedural mortality. At 6-month follow-up, an improvement in New York Heart Association (NYHA) functional class was observed in 20 of 28 patients with HF. Compared with baseline, patients with HFrEF showed significant reduced left atrial volume index (LAVI) and increased right atrial (RA) dimensions, as well as improved LVGLS and RVFWLS, at 6-month follow-up. Despite reduction in LAVI and increase in RA dimensions, improvements in biventricular longitudinal strain did not occur in HFpEF patients. Multivariate logistic regression demonstrated that LVGLS [odds ratio (OR): 5.930; 95% CI: 1.463-24.038; P = 0.013] and RVFWLS (OR: 4.852; 95% CI: 1.372-17.159; P = 0.014) were predictive of improvement in NYHA functional class after D-Shant device implantation.

Conclusion

Improvements in clinical and functional status are observed in patients with HF 6 months after implantation of a D-Shant device. Preoperative biventricular longitudinal strain is predictive of improvement in NYHA functional class and may be helpful to identify patients who will experience better outcomes following implantation of an interatrial shunt device.

Layer-specific longitudinal strain detects transmural dysfunction in chronic severe aortic regurgitation before and after aortic valve surgery

To assess if layer-specific longitudinal strain (LS) provides incremental diagnostic and prognostic value compared to global longitudinal strain (GLS) in patients with chronic severe aortic regurgitation (AR) scheduled for aortic valve surgery. Forty-one patients were examined with speckle tracking echocardiography before surgery along with 15 healthy age-matched controls. Paired strain analyses before and after surgery were available in 31 patients. Layer-specific LS analysis enabled assessment of epicardial GLS (GLSepi), endocardial GLS (GLSendo), and conventional GLS. Strain parameters were indexed to end-diastolic volume (EDV; GLS/EDV) to account for increased preload. The prognostic value of layer-specific LS was evaluated using the primary outcome of persistent LV dilatation (LVEDV ≥ 175 mL) three months after surgery. Absolute (GLS, GLSepi, GLSendo) and EDV-indexed layer-specific LS (GLS/EDV, GLSepi/EDV, GLSendo/EDV) were impaired in severe AR compared to controls at baseline (GLS:17.0 ± 3.2 vs. 20.6 ± 2.0; GLSepi:14.6 ± 2.8 vs. 18.1 ± 1.9; GLSendo:20.2 ± 3.7 vs. 23.8 ± 2.2%; GLS/EDV:0.09 ± 0.05 vs. 0.21 ± 0.05; GLSepi/EDV:0.08 ± 0.04 vs. 0.18 ± 0.04; GLSendo/EDV:0.11 ± 0.06 vs. 0.24 ± 0.05%/mL; all p < 0.001). In severe AR, GLS, GLSepi and GLSendo decreased after surgery whereas GLS/EDV, GLSepi/EDV and GLSendo/EDV increased (all p < 0.001). Impaired absolute and EDV-indexed layer-specific LS were all associated with the primary outcome (all p ≤ 0.01). Area under the curve analysis revealed similar prognostic value of GLSepi, GLSendo and GLS (GLS:0.86; GLSepi:0.87; GLSendo:0.86; p = n.s.). EDV-indexed LS did not improve the predictive value significantly (GLS/EDV:0.93; GLSepi/EDV: 0.93; GLSendo/EDV:0.92; p = n.s.). Layer-specific LS detects transmural dysfunction in chronic severe AR and predicts persistent LV dilation after surgery. Layer-specific LS or EDV-indexed LS does not provide incremental prognostic value compared to conventional GLS.

Echocardiographic and laboratory findings in coronary slow flow phenomenon: cross-sectional study and review

Background

Coronary sow-flow phenomenon (CSFP) is defined as slow passage of the contrast injected into the coronary arteries without distal obstruction of the vessel.

Methods

The present study was a cross-sectional, descriptive-analytical study performed at the Seyed-al-Shohada Heart Center during 2018–2019. The eligible patients based on the inclusion and exclusion criteria were divided into the study group showing the CSFP and the control group with normal epicardial coronary arteries.

Results

The study included 124 patients. 67.9% of the study group and 39.4% of the control group were male patients (p-value = 0.001), and the mean patient age was 52.18 ± 12.55 and 51.77 ± 10.36 years in the study and control groups, respectively (p-value = 0.18). The study group had a significantly higher BMI than the control group (p < 0.05) and also a higher prevalence of smoking and hypertension. The variables of ALC, Hct, Plt, MPV, RDW, Cr, triglyceride, TC, and LDL, were higher in the study group. Given the echocardiographic findings, the mean E wave was significantly lower in the study group, while the control group had a significantly higher GLS (p-value = 0.01). Also, left anterior descending artery was the most common artery involved with CSFP.

Conclusion

The CSFP was significantly more common in men, smokers, hypertensive patients, and patients with high BMI. Moreover, these patients had significantly higher platelet count, MPV, LDL, and FBS. Some other laboratory variables were also higher in these patients. Given the echocardiographic findings, mild diastolic dysfunction and low GLS were also observed in the study group.

Incremental Prognostic Utility of Left Ventricular Global Longitudinal Strain in Asymptomatic Patients With Significant Chronic Aortic Regurgitation and Preserved Left Ventricular Ejection Fraction

OBJECTIVES

This study sought to examine the prognostic utility of left ventricular (LV) global longitudinal strain (GLS) in asymptomatic patients with ≥III+ aortic regurgitation (AR), an indexed LV end-systolic dimension of <2.5 cm/m², and preserved left ventricular ejection fraction (LVEF).

BACKGROUND

Management of asymptomatic patients with severe chronic AR and preserved LVEF is challenging and is typically based on LV dimensions.

METHODS

We studied 1,063 such patients (age 53 ± 16 years; 77% men) seen between 2003 and 2010 (excluding those with symptoms, obstructive coronary artery disease, acute AR/dissection, aortic/mitral stenosis, more than moderate mitral regurgitation, and previous cardiac surgery). Society of Thoracic Surgeons (STS) score was calculated. The primary endpoint was mortality. Average resting LV-GLS was measured offline on 2-, 3-, and 4-chamber views using Velocity Vector Imaging (Siemens, Malvern, Pennsylvania).

RESULTS

Mean STS score, LVEF, LV-GLS, and right ventricular systolic pressure were 4.4 ± 5.0%, 57.0 ± 4.0%, -19.5 ± 0.2%, and 31.0 ± 9.0 mm Hg, respectively. In total, 671 patients (63%) underwent aortic valve surgery at a median of 42 days after the initial evaluation. At 6.8 ± 3.0 years, 146 patients (14%) had died. On multivariable Cox survival analysis, LV-GLS (hazard ratio [HR]: 1.11), STS score (HR: 1.51), indexed LV end-systolic dimension (HR: 0.50), right ventricular systolic pressure (HR: 1.33), and aortic valve surgery (HR: 0.35) were associated with longer term mortality (all p < 0.001). Sequential addition of LV-GLS and aortic valve surgery improved the C-statistic for longer term mortality for the clinical model (STS score + right ventricular systolic pressure + indexed LV end-systolic dimension) from 0.61 (95% confidence interval [CI]: 0.51 to 0.72) to 0.67 (95% CI: 0.54 to 0.87) and to 0.77 (95% CI: 0.63 to 0.90), respectively (p < 0.001 for both). A significantly higher proportion (log-rank p = 0.01) of patients with LV-GLS worse than median (-19.5%) died versus those with an LV-GLS better than median (86 of 513 [17%] vs. 60 of 550 [11%]). The risk of death at 5 years significantly increased with an LV-GLS of worse than -19%.

CONCLUSIONS

In asymptomatic patients with ≥III+ chronic AR and preserved LVEF, worsening LV-GLS was associated with longer term mortality, providing incremental prognostic value and improved reclassification.

Incremental Value of Two Dimensional Speckle Tracking Echocardiography in the Functional Assessment and Characterization of Subclinical Left Ventricular Dysfunction

Subclinical left ventricular (LV) dysfunction refers to subtle abnormalities in LV function which typically precede a reduction in the left ventricular ejection fraction (LVEF). The assessment of myocardial function using LVEF, a radial metric of systolic function, is subject to load dependence, intra-observer and inter-observer variability. Reductions in LVEF typically manifest late in the disease process thus compromising the ability to intervene before irreversible impairment of systolic performance sets in. 2-Dimensional speckle tracking echocardiography (2D-STE), a novel strain imaging modality has shown promise as a sensitive indicator of myocardial contractility. It arms the clinician with a powerful and practical tool to rapidly quantify cardiac mechanics, circumventing several inherent limitations of conventional echocardiography. This article highlights the incremental utility of 2D-STE in the detection of subclinical LV dysfunction.

Impaired myocardial function does not explain reduced left ventricular filling and stroke volume at rest or during exercise at high altitude

Impaired myocardial systolic contraction and diastolic relaxation have been suggested as possible mechanisms contributing to the decreased stroke volume (SV) observed at high altitude (HA). To determine whether intrinsic myocardial performance is a limiting factor in the generation of SV at HA, we assessed left ventricular (LV) systolic and diastolic mechanics and volumes in 10 healthy participants (aged 32 ± 7; mean ± SD) at rest and during exercise at sea level (SL; 344 m) and after 10 days at 5,050 m. In contrast to SL, LV end-diastolic volume was ∼19% lower at rest (P = 0.004) and did not increase during exercise despite a greater untwisting velocity. Furthermore, resting SV was lower at HA (∼17%; 60 ± 10 vs. 70 ± 8 ml) despite higher LV twist (43%), apical rotation (115%), and circumferential strain (17%). With exercise at HA, the increase in SV was limited (12 vs. 22 ml at SL), and LV apical rotation failed to augment. For the first time, we have demonstrated that EDV does not increase upon exercise at high altitude despite enhanced in vivo diastolic relaxation. The increase in LV mechanics at rest may represent a mechanism by which SV is defended in the presence of a reduced EDV. However, likely because of the higher LV mechanics at rest, no further increase was observed up to 50% peak power. Consequently, although hypoxia does not suppress systolic function per se, the capacity to increase SV through greater deformation during submaximal exercise at HA is restricted.

Strain Echocardiography and Myocardial Mechanics: From Basics to Clinical Applications

The aim of this review is to summarize the recent developments in strain imaging, an evolving technique – from tissue Doppler to 3D echocardiography – for resolving the complex left ventricular mechanics. Following a brief overview of the different used technique to extract myocardial deformation data, the authors summarize the role of the technique in the assessment of cardiac mechanics and its role in the clinical arena.

Decision Making in Asymptomatic Aortic Regurgitation in the Era of Guidelines

Background—

The decision-making role of exercise echocardiography in the surgical timing for aortic regurgitation remains a matter of debate because of limited data on its link with outcome. The aim of this study was to assess the role of echocardiographic measurements at rest and during exercise as predictors of valve surgery in asymptomatic aortic regurgitation.

Methods and Results—

Comprehensive resting and exercise echocardiography was performed in 159 consecutive patients (50±15 years; 80% male) with isolated moderately severe to severe aortic regurgitation and preserved left ventricular (LV) function (LV ejection fraction >50%, LV end-diastolic dimension ≤70 mm, LV end-systolic dimension ≤50 mm or ≤25 mm/m 2 ) in whom initial management was expectant. Echocardiographic measurements were performed at rest and during exercise. LV and right ventricular (RV) longitudinal strain was analyzed at rest using velocity vector imaging. Valve surgery was performed in 50 patients (31%) during 30±21 months. After adjustment for age and sex in a multivariable Cox proportional-hazards model, exercise tricuspid annular plane systolic excursion (TAPSE; hazards ratio [HR], 0.48; P =0.001) was associated with valve surgery-free, independent of resting LV strain (HR, 1.63; P =0.005), exercise LV end-diastolic volume (HR, 1.38; P =0.048), and resting RV strain (HR, 1.69; P =0.002). In sequential Cox models, a model based on clinical data (χ 2 , 20.4) was improved by resting LV strain (χ 2 , 30.1; P =0.001), resting RV strain (χ 2 , 49.7; P <0.001), and further increased by exercise TAPSE (χ 2 , 64.4; P <0.001).

Conclusions—

In asymptomatic aortic regurgitation, resting LV strain, resting RV strain, and exercise TAPSE were independently associated with the need for earlier aortic surgery.

Value of three-dimensional speckle-tracking in detecting left ventricular dysfunction in patients with aortic valvular diseases

BACKGROUND

The aim of this study was to investigate the value of three-dimensional speckle-tracking echocardiography for the detection of subclinical left ventricular dysfunction in patients with aortic valvular disease (AVD).

METHODS

Fifty-nine patients with AVD in New York Heart Association functional class I or II as well as 48 controls were recruited. Patients with AVD were divided further into those with aortic stenosis (AS; n = 34) and those with aortic regurgitation (AR; n = 25). All patients underwent conventional echocardiography and three-dimensional speckle-tracking echocardiography.

RESULTS

Analysis of variance showed global longitudinal strain to be compromised in the AR group (-16.9% vs -19.3%, P = .015) and more dramatically decreased in the AS group (-14.3% vs -19.3%, P < .001) compared with healthy controls. Impairment of global circumferential strain was observed in patients with AR (-15.9% vs -18.5%, P = .009) but not in those with AS (-18.2% vs -18.5%, P = .768). Global area strain and global radial strain were decreased in patients with AS and those with AR compared with controls, but the difference between the two subgroups was not significant.

CONCLUSIONS

Strains measured by three-dimensional speckle-tracking echocardiography are useful indices of early-stage heart dysfunction caused by AVD. Longitudinal strain is more vulnerable to pressure overload caused by AS, whereas circumferential strain is more sensitive to volume overload due to AR.