5-Year prognostic value of the right ventricular strain-area loop in patients with pulmonary hypertension

Echocardiographic Parameters of the Right Ventricle in Patients With Pulmonary Hypertension: A Review

To diagnose pulmonary hypertension (PH) and assess its severity, accurate measurement of pulmonary artery (PA) pressure is crucial. However, there can be significant discrepancies between echocardiography (Echo) and invasive catheterization. The right ventricle (RV) has a complex structure, and its remodeling in PH is diverse, making it challenging to evaluate RV physiology with a single imaging modality. While right heart catheterization is the gold standard, its practicality in clinical settings is limited. Cardiac magnetic resonance imaging (MRI) is valuable for RV evaluation, with 4-dimensional flow MRI showing promise, yet accessibility remains a concern. Thus, in PH patient management, Echo plays a central role as a practical decision-making tool. This review aims to elucidate Echo parameters in PH patients, highlighting differences in PA systolic pressure measurements, RV-PA coupling, RV remodeling patterns crucial for understanding PH progression, and clinical evidence regarding RV strain. Additionally, it aims to introduce new Echo parameters that help understand RV in PH.

Right atrial and right ventricular strain: prognostic value depends on the severity of tricuspid regurgitation

AIMS

Assessing right heart function is challenging, particularly when significant tricuspid regurgitation (TR) is present. Amongst available echocardiographic techniques for assessment, literatures suggest that strain imaging may be more reliable and less susceptible to loading conditions. Thus, we aimed to assess the validity of right atrial (RA) and right ventricular (RV) strain relative to conventional metrics as well as their utility in predicting patient outcomes in TR.

METHODS AND RESULTS

We studied 262 consecutive patients (mean age 74 ± 11.2 years, 53% male) who underwent same-day echocardiography and right heart catheterization between 2018 and 2023. We compared right heart strain to traditional metrics of RV function and subsequently correlated RA and RV strain to heart failure (HF)-related death or hospitalization, whichever came first. Over a mean follow-up of 34 ± 15 months, there were 103 deaths and HF hospitalizations. Both RA strain and RV strain were correlated with echocardiographic and invasive measures of right heart function. Across all patients, preserved RA strain was associated with lower risk of adverse outcomes [hazard ratio (HR) 0.763, 95% confidence interval (CI) 0.618-0.943]. Similarly, preserved RV strain was correlated with better outcomes, although this was only statistically significant in patients without severe TR or pulmonary hypertension (HR 2.450, 95% CI 1.244-4.825). Moreover, abnormal ratios of RV strain to pulmonary pressures and RV size were significantly correlated with adverse outcomes (P < 0.05 each).

CONCLUSION

RA and RV strain are independently correlated with echocardiographic and invasive measures of cardiac function. Moreover, preserved RA and RV strain is likely associated with better clinical outcomes.

Prognostic values of right ventricular echocardiography functional parameters for mortality prediction in precapillary pulmonary hypertension: a systematic review and meta-analysis

BACKGROUND

Echocardiographic prognostic indicators of precapillary pulmonary hypertension (PH) mortality has been inconclusive. This study aims to examine the prognostic values of right ventricular echocardiographic functional parameters in predicting precapillary PH mortality.

METHODS

Systematic searches were conducted in the ScienceDirect, Medline, and Cochrane databases for longitudinal studies. Assessments included means and hazard ratios (HRs) for Tricuspid Annular Plane Systolic Excursion (TAPSE), Right Ventricular Systolic Pressure (RVSP), Right Ventricular Longitudinal Strain (RVLS), Right Ventricular Fractional Area Change (RVFAC), Right Ventricular Ejection Fraction (RVEF), and Right Ventricular Index of Myocardial Performance (RIMP).

RESULTS

The meta-analysis included 24 cohort studies comprising 2171 participants. Mean values were as follows: TAPSE 17.62 mm, RVSP 77.50 mmHg, RVLS - 16.78%, RVFAC 29.81%, RVEF 37.56%, and RIMP 0.52. TAPSE (HR: 1.28; 95% CI 1.17-1.40; p < 0.001), RVLS (HR: 1.74; 95% CI 1.34-2.26; p < 0.001), RVFAC (HR: 1.40; 95% CI 1.13-1.75; p < 0.001), RVEF (HR: 1.08; 95% CI 1.02-1.15; p = 0.01), and RIMP (HR: 1.51; 95% CI 1.23-1.86; p < 0.001) emerged as significant prognosticators of precapillary PH mortality, with the exception of RVSP (HR: 1.04; 95% CI 0.99-1.09; p = 0.14). TAPSE summary receiver operating characteristics (sROC) analysis yielded an area under the curve (AUC) of 0.85 [95% CI 0.81-0.88] with a sensitivity of 0.81 [95% CI 0.63-0.91] and a specificity of 0.74 [95% CI 0.54-0.87]. RVLS sROC resulted in an AUC of 0.74 [95% CI 0.70-0.78] with a sensitivity of 0.74 [95% CI 0.57-0.86] and a specificity of 0.69 [95% CI 0.64-0.75].

CONCLUSIONS

TAPSE, RVLS, RVFAC, RVEF, and RIMP demonstrated promise as valuable prognostic indicators for precapillary PH mortality.

Left and right ventricular strain-volume/area loops: a narrative review of current physiological understanding and potential clinical value

Traditionally, echocardiography is used for volumetric measurements to aid in assessment of cardiac function. Multiple echocardiographic-based assessment techniques have been developed, such as Doppler ultrasound and deformation imaging (e.g., peak global longitudinal strain (GLS)), which have shown to be clinically relevant. Volumetric changes across the cardiac cycle can be related to deformation, resulting in the Ventricular Strain-Volume/Area Loop. These Loops allow assessment of the dynamic relationship between longitudinal strain change and volumetric change across both systole and diastole. This integrated approach to both systolic and diastolic function assessment may offer additional information in conjunction with traditional, static, measures of cardiac function or structure. The aim of this review is to summarize our current understanding of the Ventricular Strain-Volume/Area Loop, describe how acute and chronic exposure to hemodynamic stimuli alter Loop characteristics, and, finally, to outline the potential clinical value of these Loops in patients with cardiovascular disease. In summary, several studies observed Loop changes in different hemodynamic loading conditions and various (patho)physiological conditions. The diagnostic and prognostic value, and physiological interpretation remain largely unclear and have been addressed only to a limited extent.

Left ventricular strain-volume loops in bicuspid aortic valve disease: new insights in cardiomechanics

Aims

By combining temporal changes in left ventricular (LV) global longitudinal strain (GLS) with LV volume, LV strain-volume loops can assess cardiac function across the cardiac cycle. This study compared LV strain-volume loops between bicuspid aortic valve (BAV) patients and controls, and investigated the loop's prognostic value for clinical events.

Methods and results

From a prospective cohort of congenital heart disease patients, BAV patients were selected and compared with healthy volunteers, who were matched for age and sex at group level. GLS analysis from apical views was used to construct strain-volume loops. Associations with clinical events, i.e. a composite of all-cause mortality, heart failure, arrhythmias, and aortic valve replacement, were assessed by Cox regression. A total of 113 BAV patients were included (median age 32 years, 40% female). BAV patients demonstrated lower Sslope (0.21%/mL, [Q1-Q3: 0.17-0.28] vs. 0.27%/mL [0.24-0.34], P < 0.001) and ESslope (0.19%/mL [0.12-0.25] vs. 0.29%/mL [0.21-0.43], P < 0.001) compared with controls, but also greater uncoupling during early (0.48 ± 1.29 vs. 0.05 ± 1.21, P = 0.04) and late diastole (0.66 ± 1.02 vs. -0.07 ± 1.07, P < 0.001). Median follow-up duration was 9.9 [9.3-10.4] years. Peak aortic jet velocity (HR 1.22, P = 0.03), enlarged left atrium (HR 3.16, P = 0.003), E/e' ratio (HR 1.17, P = 0.002), GLS (HR 1.16, P = 0.008), and ESslope (HR 0.66, P = 0.04) were associated with the occurrence of clinical events.

Conclusion

Greater uncoupling and lower systolic and diastolic slopes were observed in BAV patients compared with healthy controls, suggesting presence of altered LV cardiomechanics. Moreover, lower ESslope was associated with clinical events, highlighting the strain-volume loop's potential as prognostic marker.

Left ventricular strain-volume loops and myocardial fibrosis in pediatric patients with Duchenne muscular dystrophy

BACKGROUND

The left ventricular strain-volume loop (SVL) combines changes in global longitudinal strain (GLS) and LV volume across a cardiac cycle, providing insight into cardiac dynamics. This study explored the association between left ventricular SVL and presence of fibrosis, assessed with late gadolinium enhancement, in patients with Duchenne muscular dystrophy (DMD).

METHODS AND RESULTS

34 pediatric patients with DMD were included. Feature tracking analysis was used to assess endocardial GLS and volumetric measurements to construct the SVL. Mean age at the time of assessment was 14 ± 3 and 11 ± 2 years old (p < 0.01) in the group with (n = 18) versus without fibrosis (n = 16), respectively. Left ventricular ejection fraction was not significantly different between groups (fibrosis: 56.4 ± 3.8% versus without fibrosis: 54.0 ± 6.3%, p = 0.18). After adjusting for age, the late diastolic slope of the SVL was significantly associated with presence of fibrosis (OR 0.39 [95% CI 0.18-0.85]; area under the receiver operating characteristic curve: 0.83 [95% CI 0.70-0.97]) No significant association was observed for peak strain and fibrosis (OR 1.15 [95% CI 0.86-1.546]).

CONCLUSION

A lower late diastolic slope of the left ventricular SVL, related to the interplay between longitudinal deformation and volume changes late in diastole, is associated with presence of myocardial fibrosis in pediatric patients with DMD.

Echocardiographic pressure-strain loop-derived stroke work of the right ventricle: validation against the gold standard

AIMS

Commercially available integrated software for echocardiographic measurement of stroke work (SW) is increasingly used for the right ventricle, despite a lack of validation. We sought to assess the validity of this method [echo-based myocardial work (MW) module] vs. gold-standard invasive right ventricular (RV) pressure-volume (PV) loops.

METHODS AND RESULTS

From the prospectively recruiting EXERTION study (NCT04663217), we included 42 patients [34 patients with pulmonary arterial hypertension (PAH) or chronic thromboembolic pulmonary hypertension (CTEPH) and 8 patients with absence of cardiopulmonary disease] with RV echocardiography and invasive PV catheterization. Echocardiographic SW was assessed as RV global work index (RVGWI) generated via the integrated pressure-strain MW software. Invasive SW was calculated as the area bounded by the PV loop. An additional parameter derived from the MW module, RV global wasted work (RVGWW), was correlated with PV loop measures. RVGWI significantly correlated with invasive PV loop-derived RV SW in the overall cohort [rho = 0.546 (P < 0.001)] and the PAH/CTEPH subgroup [rho = 0.568 (P < 0.001)]. Overall, RVGWW correlated with invasive measures of arterial elastance (Ea), the ratio of end-systolic elastance (Ees)/Ea, and end-diastolic elastance (Eed) significantly.

CONCLUSIONS

Integrated echo measurement of pressure-strain loop-derived SW correlates with PV loop-based assessment of RV SW. Wasted work correlates with invasive measures of load-independent RV function. Given the methodological and anatomical challenges of RV work assessment, evolution of this approach by incorporating more elaborated echo analysis data and an RV reference curve might improve its reliability to mirror invasively assessed RV SW.

Association of left ventricular strain-volume loop characteristics with adverse events in patients with heart failure with preserved ejection fraction

AIMS

Patients with heart failure with preserved ejection fraction (HFpEF) are characterized by impaired diastolic function. Left ventricular (LV) strain-volume loops (SVL) represent the relation between strain and volume during the cardiac cycle and provide insight into systolic and diastolic function characteristics. In this study, we examined the association of SVL parameters and adverse events in HFpEF.

METHODS AND RESULTS

In 235 patients diagnosed with HFpEF, LV-SVL were constructed based on echocardiography images. The endpoint was a composite of all-cause mortality and Heart Failure (HF)-related hospitalization, which was extracted from electronic medical records. Cox-regression analysis was used to assess the association of SVL parameters and the composite endpoint, while adjusting for age, sex, and NYHA class. HFpEF patients (72.3% female) were 75.8 ± 6.9 years old, had a BMI of 29.9 ± 5.4 kg/m2, and a left ventricular ejection fraction of 60.3 ± 7.0%. Across 2.9 years (1.8-4.1) of follow-up, 73 Patients (31%) experienced an event. Early diastolic slope was significantly associated with adverse events [second quartile vs. first quartile: adjusted hazards ratio (HR) 0.42 (95%CI 0.20-0.88)] after adjusting for age, sex, and NYHA class. The association between LV peak strain and adverse events disappeared upon correction for potential confounders [adjusted HR 1.02 (95% CI 0.96-1.08)].

CONCLUSION

Early diastolic slope, representing the relationship between changes in LV volume and strain during early diastole, but not other SVL-parameters, was associated with adverse events in patients with HFpEF during 2.9 years of follow-up.

Assessment of Right Ventricular Function-a State of the Art

PURPOSE OF REVIEW

The right ventricle (RV) has a complex geometry and physiology which is distinct from the left. RV dysfunction and failure can be the aftermath of volume- and/or pressure-loading conditions, as well as myocardial and pericardial diseases.

RECENT FINDINGS

Echocardiography, magnetic resonance imaging and right heart catheterisation can assess RV function by using several qualitative and quantitative parameters. In pulmonary hypertension (PH) in particular, RV function can be impaired and is related to survival. An accurate assessment of RV function is crucial for the early diagnosis and management of these patients. This review focuses on the different modalities and indices used for the evaluation of RV function with an emphasis on PH.

Imaging the right atrium in pulmonary hypertension: A systematic review and meta-analysis

BACKGROUND

Right atrial (RA) imaging has emerged as a promising tool for the evaluation of patients with pulmonary hypertension (PH), albeit without systematic validation.

METHODS

PubMed, Web of Science and the Cochrane library were searched for studies investigating the prognostic value of RA imaging assessment in patients with PH from 2000 to June 2021 (PROSPERO Identifier: CRD42020212850). An inverse variance-weighted meta-analysis of univariable hazard ratios (HRs) was performed using a random effects model.

RESULTS

Thirty-five studies were included (3,476 patients with PH; 74% female, 86% pulmonary arterial hypertension). Risk of bias was low/moderate (Quality of Prognosis Studies checklist). RA area (HR 1.06; 95% confidence interval [CI] 1.04-1.08), RA indexed area (HR 1.09; 95% CI 1.04-1.14), RA peak longitudinal strain (PLS; HR 0.94; 95% CI 0.91-0.97) and RA total emptying fraction (HR 0.96; 95% CI 0.94-0.98) were significantly associated with combined end-points including death, clinical worsening and/or lung transplantation; RA volume and volume index showed marginal significant associations. RA area (HR 1.06; 95% CI 1.04-1.07), RA indexed area (HR 1.12; 95% CI 1.07-1.17) and RA PLS (HR 0.98; 95% CI 0.97-0.99) showed significant associations with mortality; RA total emptying fraction showed a marginal association.

CONCLUSIONS

Imaging-based RA assessment qualifies as a relevant prognostic marker in PH. RA area reliably predicts composite end-points and mortality, which underscores its clinical utility. RA PLS emerged as a promising imaging measure, but is currently limited by the number of studies and different acquisition methods.

The year 2021 in the European Heart Journal—Cardiovascular Imaging: Part I

The European Heart Journal—Cardiovascular Imaging was introduced in 2012 and has during these 10 years become one of the leading multimodality cardiovascular imaging journals. The journal is currently ranked as Number 19 among all cardiovascular journals. It has an impressive impact factor of 9.130 and our journal is well established as one of the top cardiovascular journals. The most important studies published in our Journal in 2021 will be highlighted in two reports. Part I of the review will focus on studies about myocardial function and risk prediction, myocardial ischaemia, and emerging techniques in cardiovascular imaging, while Part II will focus on valvular heart disease, heart failure, cardiomyopathies, and congenital heart disease.

Right ventricular volume-strain loops using 3D echocardiography-derived mesh models: proof-of-concept application on patients undergoing different types of open-heart surgery

BACKGROUND

Right ventricular (RV) function can be quantified by right heart catheterization-derived pressure-volume loops. While this technique is invasive, echocardiography-based volume-strain loops (VSLs) potentially reflect a non-invasive alternative. In this study, an approach to generate VSLs from volume and multidimensional strain data of 3D echocardiography-derived RV mesh models is evaluated with regard to feasibility and reproducibility.

METHODS

In a retrospective cohort study design, 3D intraoperative transesophageal echocardiograms of twenty-three patients undergoing aortic valve surgery (AVS) and eighteen patients undergoing off-pump coronary artery bypass (OPCAB) grafting were available prior to sternotomy and after sternal closure. RV meshes were generated using 3D speckle-tracking. Custom-made software quantified the meshes' volumes, global longitudinal (RV-GLS) and global circumferential strain (RV-GCS) for VSL generation. Linear regression of systolic VSLs yielded slopes, intercepts and systolic areas. Polynomial regression of two orders was used to analyze systolic-diastolic coupling at 10% increments of the RV end-diastolic volume (RVEDV). Reproducibility was analyzed by fourfold double-measurements of four datasets.

RESULTS

VSL calculation was feasible from all included 3D datasets. RV-GLS remained unaltered, but RV-GCS worsened in AVS [abs. diff. (∆) 3.9%, P<0.01] and OPCAB patients (∆4.5%, P<0.001). While RV-GCS systolic areas were markedly reduced at the end of AVS (∆268mL%, P<0.01) and OPCAB (∆185mL%, P<0.001), RV-GCS slopes did not change. Systolic-diastolic uncoupling was not observed, but in trend, decreased diastolic RV-GCS after AVS (P=0.06) and increased diastolic RV-GCS after OPCAB (P=0.06) were observed. Intraclass correlation coefficients (0.84-0.98) and coefficients of variation (6.4-11.8%) indicated good reproducibility.

CONCLUSIONS

RV VSL generation using 3D echocardiography-derived mesh models is feasible. Longitudinal and circumferential strain vectors yield intrinsically different VSL indices. In future investigations, VSLs of multidimensional strains could provide further insight into periprocedural changes of RV mechanics.

Acute exercise-induced changes in cardiac function relates to right ventricular remodeling following 12-wk hypoxic exercise training

Repeated ventricular exposure to alterations in workload may relate to subsequent cardiac remodeling. We examined whether baseline acute changes in right (RV) and left ventricular (LV) function relate to chronic cardiac adaptation to 12-wk exercise training. Twenty-one healthy individuals performed 12-wk high-intensity endurance running training under hypoxia (fraction of inspired oxygen: 14.5%). Resting transthoracic echocardiography was performed before and after the training program to assess ventricular structure, function, and mechanics (including strain-area/volume loops). In addition, we examined systolic cardiac function during recumbent exercise under hypoxia at baseline (heart rate of 110-120 beats/min, "stress echocardiography"). Fifteen individuals completed training (22.0 ± 2.4 yr, 10 males). Hypoxic exercise training increased RV size, including diameter and area (all P < 0.05). With exception of an increase in RV fractional area change (P = 0.03), RV function did not change post-training (all P > 0.05). Regarding the RV strain-area loop, lower systolic and diastolic slopes were found post-training (P < 0.05). No adaptation in LV structure, function, or mechanics was observed (all P > 0.05). To answer our primary aim, we found that a greater increase in RV fractional area change during baseline stress echocardiography (r = -0.67, P = 0.01) inversely correlated with adaptation in RV basal diameter following 12-wk training. In conclusion, 12-wk high-intensity running hypoxic exercise training induced right-sided structural remodeling, which was, in part, related to baseline increase in RV fractional area change to acute exercise. These data suggest that acute cardiac responses to exercise may relate to subsequent RV remodeling after exercise training in healthy individuals.NEW & NOTEWORTHY During exercise, the right ventricle is exposed to a disproportionally higher wall stress than the left ventricle, which is further exaggerated under hypoxia. In this study, we showed that 12-wk high-intensity running hypoxic exercise training induced right-sided structural remodeling, which was, in part, related to baseline cardiac increase in RV fractional area change to acute exercise. These data suggest that acute RV responses to exercise are related to subsequent right ventricular remodeling in healthy individuals upon hypoxic training.

Speckle Tracking Imaging in Patients with Pulmonary Hypertension

BACKGROUND

Right ventricular (RV) systolic dysfunction is a strong predictor of mortality in pulmonary hypertension (PH). The goal of this study was to investigate whether right atrium (RA) and RV myocardial strain related to PH using speckle tracking echocardiography provide a superior estimation of RV systolic function than 2-dimensional (2D)-echo.

METHODS

This cross-sectional study analyzed 22 patients with a diagnosis of PH stratified by right heart catheterization, and they were compared to a control group of 22 age- and sex-matched healthy subjects.

RESULTS

Global longitudinal peak systolic strain measured in the RV free wall from the apical 4 chamber view was −15% vs. −14.5% when measured from the subcostal view (p = 0.99). Mean longitudinal strain during reservoir phase, and longitudinal strain rate during atrial reservoir and passive conduit function was significantly impaired measured in the right atrial free wall in patients with PH.

CONCLUSIONS

This study showed impaired LV contractility in patients with PH assessed by speckle tracking strain. RV free wall longitudinal strain does not correlate with any of the measurements of RV systolic function obtained by 2D echocardiography. A major strength of RV longitudinal strain is its ability to assess the RV function without the limitations of 2D parameters. The subcostal RV strain is a feasible and accurate alternative to conventional RV strain from the apical view in patients with poor acoustic apical 4-chamber windows. The RA strain and strain rates values may be a valuable additive to assess right-sided heart function.