Preload Stress Echocardiography Predicts Outcomes in Patients With Preserved Ejection Fraction and Low-Gradient Aortic Stenosis

Clinical course and decision-making in heart failure by preload stress echocardiography: a preliminary study

AIMS

Abnormal left ventricular diastolic response to preload stress can be an early marker of heart failure (HF). The aim of this study was to assess clinical course in patients with HF with preserved ejection fraction (HFpEF) who underwent preload stress echocardiography. In the subgroup analysis, we assessed the prognosis of patients with unstable signs during preload stress classified by treatment strategies.

METHODS AND RESULTS

We prospectively conducted preload stress echocardiographic studies between January 2006 and December 2013 in 211 patients with HFpEF. Fifty-eight patients had abnormal diastolic reserve during preload stress (unstable impaired relaxation: unstable IR). Of 58 patients with unstable IR, 19 patients were assigned to additional therapy by increased or additional therapy and 39 patients were assigned to standard therapy. Composite outcomes were prespecified as the primary endpoint of death and hospitalization for deteriorating HF. During a median period of 6.9 years, 19 patients (33%) reached the composite outcome. Unstable group with standard therapy had significantly shorter event-free survival than stable group. Patients with uptitration of therapy had longer event-free survival than those with standard therapy group after adjustment of laboratory data (hazard ratio, 0.20, 95% confidence interval, 0.05-0.90; P = 0.036); the 10 year event-free survival in patients with and without uptitration of therapy was 93% and 51%, respectively (P = 0.023).

CONCLUSIONS

Patients with unstable sign had significantly shorter event-free survival than patients with stable sign. After additional therapy, the prognosis of patients with unstable signs improved. This technique may impact decision-making for improving their prognosis.

Impaired Left Ventricular Circumferential Midwall Systolic Performance Appears Linked to Depressed Preload, but Not Intrinsic Contractile Dysfunction or Excessive Afterload, in Paradoxical Low-Flow/Low-Gradient Severe Aortic Stenosis

Paradoxical low-flow/low-gradient aortic stenosis (P-LFLG-AS) occurs in about one-third of patients with severe AS and preserved left ventricular (LV) ejection fraction (EF). Our aim was to differentiate between altered LV loading conditions and contractility as determinants of subtle LV systolic dysfunction in P-LFLG-AS. We retrospectively analyzed medical records of patients with isolated severe degenerative AS and preserved EF (30 subjects with P-LFLG-AS and 30 patients with normal-flow/high-gradient severe AS (NFHG-AS)), without relevant coexistent diseases (e.g., diabetes, coronary artery disease and chronic kidney disease) or any abnormalities which could account for a low-flow state. Patients with P-LFLG-AS and NFHG-AS did not differ in aortic valve area index and most clinical characteristics. Compared to NFHG-AS, subjects with P-LFLG-AS exhibited smaller LV end-diastolic diameter (LVd) (44 ± 5 vs. 54 ± 5 mm, p < 0.001) (consistent with lower LV preload) with pronounced concentric remodeling, higher valvulo-arterial impedance (3.8 ± 1.1 vs. 2.2 ± 0.5 mmHg per mL/m2, p < 0.001) and diminished systemic arterial compliance (0.45 ± 0.11 vs. 0.76 ± 0.23 mL/m2 per mmHg, p < 0.001), while circumferential end-systolic LV midwall stress (cESS), an estimate of afterload at the LV level, was similar in P-LFLG-AS and NFHG-AS (175 ± 83 vs. 198 ± 69 hPa, p = 0.3). LV midwall fractional shortening (mwFS) was depressed in P-LFLG-AS vs. NFHG-AS (12.3 ± 3.5 vs. 14.7 ± 2.9%, p = 0.006) despite similar EF (61 ± 6 vs. 59 ± 8%, p = 0.4). By multiple regression, the presence of P-LFLG-AS remained a significant predictor of lower mwFS compared to NFHG-AS upon adjustment for cESS (β ± SEM: −2.35 ± 0.67, p < 0.001); however, the significance was lost after further correction for LVd (β = −1.10 ± 0.85, p = 0.21). In conclusion, the association of P-LFLG-AS with a lower cESS-adjusted mwFS, an index of afterload-corrected LV circumferential systolic function at the midwall level, appears secondary to a smaller LV end-diastolic cavity size according to the Frank−Starling law. Thus, low LV preload, not intrinsic contractile dysfunction or excessive afterload, may account for impaired LV circumferential midwall systolic performance in P-LFLG-AS.

Effects of Radiofrequency Catheter Ablation on Cardiac Reserve Using Preload Stress Echocardiography in Paroxysmal and Persistent Atrial Fibrillation

The effects of catheter ablation on exercise tolerance and quality of life in patients with atrial fibrillation (AF) have been reported. We assessed cardiac function in more detail using the leg positive pressure (LPP) technique and found that contractile reserve is particularly important in relation to exercise tolerance and prognosis. In this study, we used the LPP technique to examine changes in contractile reserve immediately after ablation and 6 months later. We prospectively enrolled patients who underwent catheter ablation for AF at 2 institutes. We performed LPP stress echocardiography 2 to 3 days after (FU-1) and 6 months after (FU-2) ablation to examine changes in cardiac function indexes. The primary end point was improvement in contractile reserve. Ultimately, 109 patients (mean age 67.4 ± 9.6 years; 70% men) underwent 2 sessions of LPP stress echocardiography. The median CHA₂DS₂-VAS_C score was 2 (interquartile range 13). From FU-1 to FU-2, the change in the stroke volume index after the LPP maneuver increased in patients with paroxysmal and persistent AF with low CHA₂DS₂-VAS_C scores (both p <0.05). Regardless of AF subtype, contractile reserve at FU-2 improved in patients with low CHA₂DS₂-VAS_C scores compared with that at FU-1. In contrast, patients with high CHA₂DS₂-VAS_C scores had no change. In conclusion, patients with AF with a low CHA₂DS₂-VAS_C score had improved contractile reserve after ablation, whereas patients with high scores did not show any improvement. Aggressive interventions in patients with high scores may lead to better management after catheter ablation.

Deterioration of biventricular strain is an early marker of cardiac involvement in confirmed sarcoidosis

AIMS

Risk assessment of developing cardiac involvement in systemic sarcoidosis can be challenging because of limited data. Recently, attention has been given to left ventricular and right ventricular (LV and RV) involvement in cardiac sarcoidosis (CS) and its prevalence, relevance, and prognostic value. The aim of this study was to assess the role of biventricular strain to predict prognosis in confirmed sarcoidosis patients.

METHODS AND RESULTS

LV and RV longitudinal strains (LSs) were evaluated by 2D speckle tracking in 139 consecutive confirmed sarcoidosis patients without other pre-existing structural heart diseases, and 52 age- and gender-matched control subjects. The primary endpoint was CS-related events (cardiac death or development of cardiac involvement). Sarcoidosis without cardiac involvement had significantly lower LV and RV free wall LS compared with control subjects. Basal LS had a higher area under the curve for differentiation of sarcoidosis in patients without cardiac involvement compared to control (cut-off value: -18% with 89% sensitivity and 69% specificity). During a median period of 50 months, the occurrence of CS-related events was observed in 20 patients. In a multivariate analysis, basal LV LS and RV free wall LS were associated with the events [hazard ratio (HR) 0.72, P < 0.001 and HR: 0.83, P = 0.006, respectively]. Patients with impaired biventricular function had significantly shorter event-free survival than those with preserved biventricular function (P < 0.001).

CONCLUSION

Deterioration of biventricular strain was associated with CS-related events. This information might be useful for clinical evaluation and follow-up in sarcoidosis.

Predictive value of left atrial function for latent paroxysmal atrial fibrillation as the cause of embolic stroke of undetermined source

BACKGROUND

In patients with embolic stroke of undetermined source (ESUS), paroxysmal atrial fibrillation (AF) is often diagnosed, however, the risk of paroxysmal AF in ESUS has not been well described. Several studies have suggested a linkage between left atrial (LA) functional parameters and risk of AF in stroke patients. The aim of this study was to assess the role of LA functional parameters as predictors of latent paroxysmal AF in ESUS on admission.

METHODS

Between January 2015 and December 2019, consecutive stroke patients with suspected ESUS at admission were prospectively included in this study. They were under hospital electrocardiographic monitoring for detection of new-onset AF. Various echocardiographic parameters including left atrial strain were assessed for association with new-onset AF.

RESULTS

We gathered 1082 consecutive patients with ischemic stroke. After exclusions, 121 patients with suspected ESUS at admission formed the study cohort. New-onset AF was detected in 46 (38%) patients during hospital electrocardiographic monitoring (median follow-up: 18 days). LA pump and reservoir strains were significantly and independently associated with new-onset AF. Receiver operating characteristic analysis for the association with new-onset AF showed that the areas under the curve (AUCs) of clinical parameters plus one of each strain (LA pump strain: AUC: 0.86±0.04 and LA reservoir strain: AUC: 0.76±0.05) models were significantly better than plus LA volume index (AUC: 0.68±0.04, compared p-values <0.05).

CONCLUSIONS

LA strain was significantly associated with new development of AF. Patients with impaired LA function at admission should be carefully monitored to find AF.

Review: application of current imaging modalities in the management of left-sided valvular heart disease

In terms of valvular heart disease (VHD) imaging, transthoracic echocardiography (TTE) is the preferred first choice because of its widespread availability. Other modalities, such as transesophageal echocardiography, computed tomography and magnetic resonance imaging, have played a supplementary role in diagnosis for severity, deciding the timing/type of treatment, detection of post procedural complications, and prognostic predictions. However, there are few consensuses on how to employ these modalities, as the evidence is not extensive as that for TTE. On the other hand, these imaging modalities also have their own unique strengths. If employed properly, these modalities have the potential to play a more prominent role in clinical decision making. In this review, we focus on the potential, limitations and application of current imaging modalities in the management of left-sided VHD.

Left Atrial Strain Associated with Functional Recovery in Patients Receiving Optimal Treatment for Heart Failure

BACKGROUND

Heart failure with recovered ejection fraction (HFrecEF) has been reported in several previous studies to have a better prognosis than heart failure with reduced ejection fraction (HFrEF). However, the factors associated with HFrecEF have not been identified. The aim of this study was to test the hypothesis that left atrial (LA) strain could help identify patients with recovered ejection fraction (EF) among those with heart failure (HF) with low EF on admission.

METHODS

One hundred consecutive patients hospitalized for the first time for new-onset HF were enrolled. Patients were clinically diagnosed with HFrEF on admission (left ventricular EF < 40%) and received optimal treatment for HF. Twenty-eight patients improved to HFrecEF during 6 months of follow-up.

RESULTS

Regarding clinical background, there were significantly more women and a lower rate of atrial fibrillation in the HFrecEF group than in the HFrEF group. In a multivariate logistic regression analysis, LA strain was an independent predictor of HFrecEF, even after adjustment for gender and left ventricular EF (odds ratio: 4.06; 95% CI: 2.04-8.07; P < .001). A cutoff value of 10.8% for LA strain showed high sensitivity (96%) and specificity (82%) in identifying HFrecEF in patients with HF presenting with low EF on admission. During a follow-up period of 24 ± 13 months, 31 patients (31%) had cardiovascular death or readmission for HF. Patients with reduced LA strain (<10.8%) had significantly shorter event-free survival than those with preserved LA strain (P = .02).

CONCLUSIONS

LA strain is a useful indicator for predicting HFrecEF and should be considered as a routine measurement in patients with HFrEF on admission.

Clinical Application of Stress Echocardiography in Management of Heart Failure

The key to understanding hemodynamics in heart failure (HF) is the relation between elevated left ventricular (LV) filling pressure and cardiac output. Some patients show abnormal response to stress in the relationship between LV filling pressure and cardiac output. In patients with preserved diastolic function, cardiac output can be increased without significantly elevated filling pressure during stress. In patients with HF, as long as the Frank-Starling mechanism operates effectively, cardiac output can increase while acquiring elevated filling pressure. In patients with decompensated HF, hemodynamic stress will lead to a much greater elevation in filling pressure and pulmonary venous hypertension.

Prognostic Impact of the Ratio of Acceleration Time to Ejection Time in Patients With Low Gradient Severe Aortic Stenosis and Preserved Ejection Fraction

The clinical management of patients with low gradient severe aortic stenosis (LG-SAS) and preserved left ventricular ejection fraction (LVEF) remains challenging owing to their heterogeneity. The aim to this study was to evaluate the relation between an ejection dynamic parameter linked to AS severity and outcome, the ratio of acceleration time (AT) to ejection time (ET), in a cohort of patients with LG-SAS and preserved LVEF. Three hundred and fifty-six patients with LG-AS (defined by AVA ≤1 cm² and/or AVAi ≤0.6 cm²/m² and mean aortic pressure gradient <40 mm Hg) and preserved LVEF ≥50% were studied. The relation between AT/ET and all-cause and cardiac mortality during follow-up was studied. Median follow-up was 41 months (interquartile range, 35 to 47 months). Median AT/ET was 0.32 (interquartile range, 0.29 to 0.36). The 5-year estimates of all-cause and cardiac mortality were respectively 57 ± 7%, 36 ± 7% for patients with AT/ET >0.36 versus 43 ± 4%, 16 ± 3% for patients with AT/ET ≤0.36 (p = 0.024 and p <0.001, respectively). After adjustment on known predictors of outcome including aortic valve replacement used as a time-dependent covariate, there was a significant increase in all-cause mortality risk for patients with AT/ET >0.36 (adjusted hazard ratio 2.04 [95% confidence interval, 1.32 to 3.13]; p = 0.001) and cardiac mortality risk (adjusted hazard ratio 2.89 [95% confidence interval, 1.54 to 5.43]; p<0.001) compared with patients with AT/ET ≤0.36. The association of AT/ET >0.36 and all-cause or cardiac mortality risk was consistent in subgroups of patients with LG-SAS and preserved EF. In conclusion, an AT/ET ratio of more than 0.36 is an independent predictor of mortality in patients with LG-SAS and preserved EF.

Outcome of Normal-Flow Low-Gradient Severe Aortic Stenosis With Preserved Left Ventricular Ejection Fraction: A Propensity-Matched Study

Background

Normal‐flow, low‐gradient severe aortic stenosis (NF‐LG‐SAS), defined by aortic valve area <1 cm², mean gradient <40 mm Hg, and indexed stroke volume >35 mL/m², is the most prevalent form of low‐gradient aortic stenosis (AS). However, the true severity of AS and the management of NF‐LG‐SAS are controversial. The aim of this study was to evaluate the outcome of patients with NF‐LG‐SAS compared with moderate AS (MAS) and with high‐gradient severe‐AS (HG‐SAS).

Methods and Results

A total of 154 patients with NF‐LG‐SAS, 366 with MAS (aortic valve area between 1.0 and 1.3 cm²), and 1055 with HG‐SAS were included. On multivariate analysis, after adjustment for covariates of prognostic importance, NF‐LG‐SAS patients did not exhibit an excess risk of mortality compared with MAS patients under medical management (hazard ratio=1.13 [95% CI, 0.82‐1.56]; P=0.45) and under medical and surgical management (hazard ratio 1.06 [95% CI, 0.79‐1.43]; P=0.70), even after further adjustment for aortic valve replacement (hazard ratio=1.09 [95% CI, 0.81‐1.48]; P=0.56). The 6‐year cumulative incidence of aortic valve replacement (performed in accordance with guidelines) was comparable between the 2 groups (39±4% for NF‐LG‐SAS and 35±3% for MAS, P=0.10). After propensity score matching (n=226), NF‐LG‐SAS and MAS patients also had comparable outcomes under medical (P=0.41) and under medical and surgical management (P=0.52). NF‐LG‐SAS had better outcomes than HG‐SAS patients (adjusted hazard ratio 1.84 [95% CI, 1.18‐2.88]; P<0.001).

Conclusions

This study shows that patients with NF‐LG‐SAS have a comparable outcome to those with MAS when aortic valve replacement is performed during follow‐up according to guidelines, mostly at the stage of HG‐SAS. Rigorous echocardiographic assessment to rule out measurement errors and close follow‐up are essential to detect progression to true severe AS in NF‐LG‐SAS.

Clinical application of stress echocardiography for valvular heart disease

Stress echocardiography is widely used to assess several cardiovascular diseases, including ischemic heart disease, valvular heart disease (VHD), heart failure, congenital heart disease, and pulmonary hypertension. In valvular heart disease with asymptomatic severe or symptomatic non-severe status, stress echocardiography plays a central role in the management. As of 2017, the updated American College of Cardiology/American Heart Association and European Society of Cardiology/European Association for Cardio-Thoracic Surgery VHD guidelines recommended stress testing to (1) confirm symptoms and (2) evaluate the hemodynamic response to exercise. In patients with undetermined VHD severity in the presence of low-flow status, it can also be helpful to determine whether the VHD is severe based on flow-dependent changes in response to stress. The clinical indications of stress echocardiography in VHD have expanded with growing evidence for prognosis and being an early marker for interventions. As a result, demand has increased in major cardiology societies for the standardization of stress echocardiography in VHD. Echocardiographic centers should be aware of the clinical potential of stress echocardiography to ensure its optimal application and performance in VHD. This article reviews the clinical application of stress echocardiography, including dobutamine, semisupine bicycle, treadmill, and leg-positive pressure for VHD patient management, and focuses on the current consensus regarding the use of stress echocardiography in VHD. Stress echocardiography is safe and should be encouraged, especially in heart valve clinics, to understand the complex mechanism in asymptomatic patients.

Right Ventricular Function and Beneficial Effects of Cardiac Rehabilitation in Patients With Systolic Chronic Heart Failure

BACKGROUND

It has been recognized that a comprehensive cardiac rehabilitation (CR) program improves mortality in patients with chronic heart failure. On the other hand, the magnitude of the improvement in exercise capacity after CR differs among individuals. The aim of this study was to assess the echocardiographic determinants of responders to CR using preload stress echocardiography.

METHODS

We prospectively enrolled 58 chronic heart failure patients with reduced left ventricular ejection fraction (aged 62 ± 11 years; 69% male; left ventricular ejection fraction 43% ± 7%) who had received optimized medical treatment in a CR program for 5 months. We performed preload echocardiographic studies using leg positive pressure (LPP) to assess the echocardiographic parameters during preload augmentation. We defined 41 patients as a development cohort to assess the predictive value of echocardiographic variables. Next, we validated results in the remaining 17 patients as a validation cohort.

RESULTS

In the development cohort, significant improvement in peak oxygen uptake (VO₂) (>10%) after CR was observed in 58% patients. In a multivariable logistic regression model, the significant predictor of improvement in exercise capacity was right ventricular (RV) strain during LPP (odds ratio: 3.96 per 1 standard deviation; P = 0.01). An RV strain value of -16% during LPP had a good sensitivity of 0.79 and a specificity of 0.71 to identify patients with improvement in peak VO₂. In the validation cohort, an optimal cutoff value of RV strain value was the same (area under the curve: 0.77, sensitivity: 0.78, specificity: 0.65).

CONCLUSIONS

RV strain during LPP may be an echocardiographic parameter for assessing beneficial effects of CR.