Right ventricular myocardial work: proof-of-concept for the assessment of pressure-strain loops of patients with pre-capillary pulmonary hypertension

Abstract

Background

Right ventricular myocardial work (RVMW) assessed by transthoracic echocardiography allows to study the right ventricular (RV) function using RV pressure-strain loops. The assessment of these novel indexes of RVMW has not yet been exten sively studied, namely in pre-capillary pulmonary hypertension (PH) population.

Objectives

to evaluate the relationship between RVMW and invasive indices of right heart catheterization (RHC) in a cohort of patients with group I and group IV PH and to compare with a control group without PH.

Methods

A prospective registry of pre-capillary PH patients was used and compared with a control group without PH. In both groups, patients underwent same day RHC and echocardiographic assessment. Dedicated software for left ventricle myocardial work was used for the RV. RV global work index (RVGWI) was calculated as the area of the RV pressure-strain loops. From RVGWI, RV global constructive work (RVGCW), RV global wasted work (RVGWW), and RV global work efficiency (RVGWE) were estimated.

Results

25 pts were included: 17 pts with PH were compared with 8 pts without PH. RVGWI, RVGCW and RVGWW were significantly higher in PH patients than in controls (p < 0,05), while RVGWE was significantly lower (p < 0,05). Significant correlations were found between mean pulmonary artery pressure, cardiac index, venous oxygen saturation, NT-proBNP and RVGCW, RVGWW and RVGWE; between pulmonary vascular resistance, cardiac output, right ventricular stroke work and RVGWI, RVGCW, RVGWW and RVGWE; between stroke volume and RVGWW and RVGWE; between pulmonary artery pulsatility index and RVGWI, RVGCW and RVGWW; between RA pressure and RVGWE.

Conclusions

Patients with pre-capillary PH present significantly higher RVGWI, RVGCW and RVGWW and lower RVGWE than patients without PH. Echocardiographic RVMW-derived indexes show significant correlation with invasive measurements and NT-proBNP. Larger studies are needed to assess the prognostic value of these novel indexes.

Graphical Abstract

Background

In pre-capillary pulmonary hypertension (PH), particularly in groups I and IV, the right ventricle (RV) function plays a pivotal role in prognosis stratification. The latest ESC/ERS Guidelines for the diagnosis and treatment of PH have narrowed down the utility of echocardiography for risk stratification to three parameters: right atrium (RA) end-systolic area, TAPSE/SPAP ratio, and the presence of pericardial effusion [1]. The scaling down is due to the suboptimal performance of other echocardiographic parameters in assessing RV function.

Compared to conventional parameters, such as tricuspid annular plane systolic excursion (TAPSE), echocardiography-derived RV longitudinal strain is angle-independent and less affected by loading conditions [2]. It has been shown to be valuable in predicting outcomes for individuals with PH [3]. Similarly, global longitudinal strain (GLS) of the left ventricle (LV) has proven useful in prognostication for various cardiovascular diseases [4, 5].

Recently, through speckle tracking, that allows evaluation of strain, a new echo-derived parameter has emerged, allowing the non-invasive analysis of LV pressure-volume loops: LV Myocardial Work [6]. This echo-derived myocardial work parameter allows the comprehensive evaluation of the LV systolic function, accounting for both afterload and LV desynchrony [7]. LV myocardial work integrates three variables: speckle tracking echo-derived LV GLS, echo-derived cardiac cycle timing, and non-invasive brachial cuff blood pressure, serving as a surrogate for afterload [8].

Given the thinner walls and lower ventricular elastance of the RV, RV GLS is more afterload-dependent than LV GLS [9, 10]. The RV has an unique capability to adapt to chronic increases in afterload by enhancing contractility to maintain cardiac output. Consequently, it is essential to assess both contractility and afterload (i.e., right ventriculo-arterial coupling) to evaluate RV dysfunction [11]. This raises the question of whether a similar echo-derived myocardial work parameter could be developed for the RV.

The rationale behind this investigational study was to assess Right Ventricular Myocardial Work (RVMW) using transthoracic echocardiography (TTE) and incorporating pressure values from right heart catheterization (RHC) as a surrogate for afterload. This approach would allow the study and analysis of RV function using RV pressure-strain loops. The association between these novel RVMW indexes and multiple invasive hemodynamic parameters has not been extensively studied, particularly in the pre-capillary PH population. Hence, this study aimed to compare RVMW indexes between a cohort of patients with group I and group IV PH and a control group without PH and to evaluate the relationship between RVMW and invasive indices of RHC.

Methods

Study population

This proof-of-concept study represents an observational post-hoc examination derived from two ongoing prospective registries conducted at our center. The first registry includes consecutive patients with groups I and IV PH, enrolled since September 2022, that underwent RHC and TTE on the same day. The second registry, from which our control group was derived, consists of consecutive patients with high and intermediate-high risk pulmonary embolism considered appropriate for catheter-directed therapy. The second registry, spanning since November 2020, involved prospective enrollment in a multiparametric follow-up protocol, which included RHC and TTE conducted on the same day at the 3-month post-acute pulmonary embolism. From this cohort, 8 patients without PH, as confirmed by RHC, were randomly selected as the control group. The study protocol complies with the hospital ethic committee policy. All participants provided written informed consent and all procedures carried out in this study were conducted according to the Declaration of Helsinki guidelines.

Study protocol

All patients of both groups were analyzed for baseline characteristics, 6-minute walking test (6MWT), NT-proBNP, RHC and TTE.

Right heart catheterization

Femoral vein or right antecubital basilic vein were the access routes used. RHC using an Arrow Berman catheter (Teleflex) was performed by fluoroscopy guidance. RA pressure, systolic, diastolic and mean pulmonary artery pressure (PAP) were measured, as well as pulmonary artery wedge pressure (PAWP), employing standard techniques [12]. Pressure curves were recorded and analyzed by a skilled operator, with values averaged over ten heartbeats, at end-expiration. Oxygen venous saturation (SvO2) was recorded. Cardiac index (CI) was determined by indexing cardiac output (CO), using the indirect Fick method [12], adjusted for body surface area. Stroke volume (SV = CO/heart rate), Stroke volume index (SVI = CI/heart rate), pulmonary vascular resistance (PVR = (mean PAP - PAWP)/CO), pulmonary artery pulsatility index (PAPI = (systolic PAP – diastolic PAP)/RA pressure), RV stroke work (RVSW = SV × (mean PAP - RA pressure) × 0.0136) and RV stroke work index (RVSWI = SVI × [mean PAP - RA pressure] × 0.0136) were calculated. RVSW and RVSWI represent the total mechanical work (or energy) done by the RV per beat and per beat per unit body surface area, respectively [13]. Mean arterial blood pressure and heart rate were measured non-invasively. According with the ESC/ERS 2022 guidelines [1], pre-capillary PH was defined as mean PAP > 20mmHg, PVR > 2 WU, and PAWP ≤ 15mmHg.

Transthoracic echocardiography

TTE evaluation was performed by experienced operators, using GE Vivid E95^® echocardiographs, according to the American Society of Echocardiography/European Association of Cardiovascular Imaging recommendations [14, 15]. TTE was conducted on the same day as the RHC. All echocardiographic images were digitally stored and subsequently analyzed using EchoPAC software (General Electric Vingmed Ultrasound, USA). Echocardiographic parameters were averaged over three consecutive beats, if in sinus rhythm, or four to six beats, if in atrial fibrillation. TTE assessment of the right heart included the evaluation of RV function, namely tricuspid annular peak systolic velocity (RV S’), TAPSE, RV fractional area change (FAC), RV GLS and free wall longitudinal strain (FWLS), as well as, estimated systolic PAP (SPAP), TAPSE/SPAP ratio, FWLS/SPAP ratio, RA area and indexed volume, RV basal diameter and RV end-diastolic area. Left ventricle ejection fraction (LVEF) was measured using the Simpson method. Tricuspid regurgitation was assessed using color Doppler interrogation in the apical four-chamber view with acquisition of a clearly delineated continuous-wave Doppler of tricuspid regurgitation signal for accurate calculation of peak tricuspid regurgitation velocity (TRV). RA pressure was estimated using inferior vena cava cine registration during a complete respiratory cycle in order to evaluate its diameter and collapsibility. By applying the modified Bernoulli equation, maximum RV-RA gradient was estimated from peak TRV. SPAP was calculated by adding the maximum RV–RA pressure gradient to estimated RA pressure. Estimated RA pressure was obtained based on the diameter and collapsibility of the inferior vena cava [14]. Peak TRV could not be measured in three patients of the cohort without PH, preventing the estimation of SPAP in those individuals. In those 3 patients, TAPSE/SPAP and FWLS/SPAP ratios were calculated using systolic PAP from RHC.

Right ventricular myocardial work

The novel parameters of RVMW were analyzed using proprietary software originally developed for the assessment of LV myocardial work by two-dimensional speckle tracking echocardiography (EchoPAC Version 204), adapted for RVMW analysis, as previously described [16]. The software enabled the synchronization of RV GLS values, measured in an RV-focused apical 4-chamber view, with measured pulmonary pressures (systolic and diastolic PAP) obtained invasively. After RV GLS was measured, synchronization of cardiac cycle timing was determined, using pulsed-wave Doppler at the pulmonic valve in the right ventricular outflow tract and direct visualization of valve leaflets the tricuspid valve. Subsequently, RV pressure-strain loops were generated within the software. Four parameters of RVMW were then derived from the analysis of the RV pressure-strain loops: (1) RV global work index (RVGWI, mmHg%) was calculated as the area of the RV pressure-strain loops. From RVGWI, (2) RV global constructive work (RVGCW, mmHg%; work contributing to myocardial shortening during systole and lengthening during isovolumic relaxation), (3) RV global wasted work (RVGWW, mmHg%; work contributing to myocardial lengthening during systole and shortening during isovolumic relaxation), and (4) RV global work efficiency (RVGWE, %; relation between RVGCW and the sum of RVGCW and RVGWW) were estimated.

Statistical analysis

Patients with and without PH were compared regarding baseline characteristics, NT-proBNP, 6MWT, RHC and TTE measurements, namely RVMW. Continuous variables are presented in mean value and standard deviation (SD) when normal distribution of data was found, or median and interquartile ranges (IQR) when non-normal distribution was found. Normal distribution was confirmed using the Kolmogorov-Smirnov test, or skewness and kurtosis. The categorical variables are presented as absolute frequency (n) and relative frequency (%). Group comparison was tested with independent sample t-test for normal distribution continuous variables, Mann-Whitney test for non-normal distribution continuous variables, chi-square and Fisher’s exact test for categorical variables. Correlation was assessed using the Pearson r and Spearman rho coefficient as appropriate. Twenty individuals were selected randomly for the evaluation of interobserver and intraobserver agreement using intraclass correlation coefficients (ICC) and Bland-Altman plots. The second observer was blinded to the measurements of the first observer for interobserver measurements. Intraobserver measurements were performed offline after a 4-week interval. Statistical significance was defined as a p-value < 0.05. All tests were two-sided. The software used for statistical analysis was SPSS version 25.0 (SPSS Inc., Chicago, IL, USA).

Results

Clinical characteristics

Twenty-five patients were included: 17 patients with pre-capillary PH (9 patients with group I and 8 patients with group IV) were compared with 8 patients without PH. In the nine patients within group I PH, the etiologies were idiopathic in four cases, connective tissue disease in three, HIV infection in one, and a heritable form in one patient. All group IV patients were chronic thromboembolic pulmonary hypertension cases.

Patients with PH were older (67 vs. 53 years, p = 0.006) and more frequently female (68% vs. 25%, p = 0.011) when compared to the control group. Of the PH patients, 68% were in WHO class II or III and 76% were in vasodilatory therapy (Table 1). When compared with the control group, patients with PH had worse 6MWT (291 vs. 591 m, p = 0.004) and higher NT-proBNP levels (878 vs. 67 pg/ml, p = 0.001).

Table 1 Comparison of groups of baseline characteristics, right heart catheterization parameters and echocardiographic parameters (6MWT – 6-minute walking test; FWLS – free wall longitudinal strain; GLS – global longitudinal strain; IQR – interquartile range; LVEF – left ventricle ejection fraction; PDE-5 – phosphodiesterase 5; RV – right ventricle; RVGCW – right ventricular global constructive work; RVGWW – right ventricular global wasted work; RVGWE – right ventricular global work efficiency; RVGWI – right ventricular global work index; RVSW – right ventricle stroke work; RVSWI – right ventricle stroke work index; SD – standard deviation; SPAP – systolic pulmonary artery pressure; TAPSE – tricuspid annular plane systolic excursion; WHO – World Health Organization)

RHC parameters

All patients underwent RHC. As expected, all invasive parameters were significantly different between patients with and without PH. Besides standard measurements such as mean PAP, PVR, CO, CI, RA pressure and SvO2, other measurements of RV function and cardiac work, such as SV, SVi, RVSW, RVSWi and PAPI were calculated. Among the 25 patients that underwent RHC, there were no reported complications. RHC data is summarized in Table 1.

Conventional echocardiographic parameters

Patients with PH had larger RA indexed volumes (36 ± 11.7 vs. 21 ± 6.0 ml/m2, p = 0.017) and areas (21 (8) vs. 16.5 (5) cm [2], p = 0.030) and higher estimated SPAP (74.2 ± 27.5 vs. 26 ± 5.8 mmHg, p < 0.001) and lower RV S’ (9 ± 2.0 vs. 15 ± 3.5 cm/s, p = 0.001). TAPSE/SPAP ratio (0.30 ± 0.12 vs. 0.86 ± 0.16 mm/mmHg, p < 0.001), RV GLS (−14.3 ± 4.54 vs. −20.7 ± 3.45%, p = 0.002), FWLS (− 15.8 ± 6.64 vs. −21.2 ± 3.74%, p = 0.048) and FWLS/SPAP ratio (−0.26 ± 0.18 vs. – 0.86 ± 0.28%/mmHg, p < 0.001) were significantly lower in patients with PH than in patients without PH. Lastly, TAPSE (20 ± 4.6 vs. 22 ± 1.8 mm, p = 0.128) and FAC (37 ± 12.9 vs. 47 ± 3.8%, p = 0.063), although reduced in patients with PH, the difference did not reach statistical significance. TTE data is summarized in Table 1.

Right ventricular myocardial work parameters

RVGWI (636 ± 196.6 vs. 330 ± 108.5 mmHg%, p < 0.001), RVGCW (937 ± 188.3 vs. 476 ± 139.0 mmHg%, p < 0.001) and RVGWW (152 (203) vs. 70 (107) mmHg%, p = 0.039) were significantly higher in PH patients than in controls, while RVGWE (84 (17) vs. 88 (8) %, p = 0.049) was significantly lower (Table 1; Fig. 1).

Fig. 1

Comparison of RVMW indexes between patients with and without pre-capillary PH

Relationship between RVMW and RHC parameters and NT-proBNP

Significant correlations (Table 2) were found between mean PAP, CI, SvO2, NT-proBNP and RVGCW, RVGWW and RVGWE; between PVR, CO, RVSW, RVSWI and RVGWI, RVGCW, RVGWW and RVGWE; between SV, SVi and RVGWW and RVGWE; between PAPI and RVGWI, RVGCW and RVGWW; between RA pressure and RVGWE.

Table 2 Correlations of RVMW indexes with invasive hemodynamic parameters and NT-proBNP (RVGCW – Right Ventricular global constructive work; RVGWW – Right Ventricular global wasted work; RVGWE – Right Ventricular global work efficiency; RVGWI – Right Ventricular global work index; RVMW – right ventricular myocardial work)

Interobserver and intraobserver variability

The ICC (Supplementary Table 1) for interobserver variability was 0.908 for RVGCW (p < 0.001), 0.929 for RVGWW (p < 0.001) and 0.921 for RVGWE (p < 0.001), demonstrating excellent reliability. The ICC for interobserver variability for RVGWI was 0.870 (p < 0.001), demonstrating good reliability. As for intraobserver variability, the ICC was 0.942 for RVGWI (p < 0.001), 0.983 for RVGCW (p < 0.001), 0.941 for RVGWW (p < 0.001) and 0.945 for RVGWE (p < 0.001), demonstrating excellent reliability. Bland–Altman plots for assessing the interobserver and intraobserver variability of the RVMW indexes are shown in Fig. 2.

Fig. 2

Bland–Altman Plots for interobserver (top) and intraobserver (bottom) agreement for RVMW parameters

Discussion

In this study, we investigated RV function by integrating strain and pulmonary pressures to assess RVMW by pressure-strain loops in patients with RV hemodynamic overload and healthy controls. The main findings were:

• 1) patients with pre-capillary PH had significantly higher values of RVGWI, RVGCW and RVGWW, and RVGWE was significantly lower, compared to the control group. These findings suggest that RVMW is altered in patients with pre-capillary PH.

• 2) significant correlations between RVMW parameters and several invasive hemodynamic parameters were found, emphasizing the physiological relevance of these indices in assessing RV performance under different loading conditions.

• 3) The interobserver and intraobserver agreements were strong, indicating high reliability and consistency in the measurements.

RVMW in PH vs. non-PH

The findings of this study contribute to the growing body of literature on RVMW assessment in PH [17,18,19,20,21] and add valuable insights into its clinical relevance. Our study shows the feasibility of the measurement of RVMW indices and compares them between patients with and without PH. Research has shown that RV longitudinal strain, assessed through speckle tracking echocardiography, is influenced by afterload, although to a lesser extent than other conventional indicators of RV systolic function [22, 23]. Thus, by accounting for afterload, RVMW offers insight into RV-pulmonary artery coupling, potentially offering a more accurate assessment of RV systolic function [24]. Our findings show that RVGWI and RVGCW are elevated in patients with PH, suggesting, at first sight, that the RV function in these patients may seem “stronger” compared to those without PH. However, in patients with PH, RVGWW is also significantly higher, to such an extent that when assessing the relationship between constructive work (work contributing to myocardial shortening during systole and lengthening during isovolumic relaxation) and wasted work (work contributing to myocardial lengthening during systole and shortening during isovolumic relaxation), RVGWE is inferior in these patients compared to those without pressure overload. Other studies studying patients with pressure or volume overload to the right heart have demonstrated similar results [17,18,19]. In contrast, patients with heart failure with reduced ejection fraction show not only higher RVGWW and lower RVGWE values but also lower RVGWI and RVGCW values compared to healthy controls [16]. This difference may be due to the different etiology of RV dysfunction. As right heart failure in PH is frequently a direct result of increased afterload, rather than only the consequence of primary myocardial disease, a comprehensive physiologic analysis of the cardiopulmonary unit is necessary to correctly interpret clinical and imaging data [11]. In the LV subjected to overloading conditions, such as hypertension, similar changes in myocardial work occur as in the RV of patients with PH [25, 26]. Concentric remodeling and hypertrophy of the LV are linked to increased LV global constructive work and LV global wasted work, with a disproportionately higher increase in global wasted work, leading to lower global work efficiency. Conversely, LV dilation is associated with an increase in global wasted work alone [27]. Unlike pressure or volume overload, patients with cardiomyopathies exhibit impaired LV myocardial work indices compared to healthy controls [25,26,27,28,29].

Finally, not only were RVMW indices different between groups, but two additional measures of RV-arterial coupling, TAPSE/SPAP and FWLS/SPAP, also differed significantly. TAPSE/SPAP ratio has been is commonly utilized for diagnosis, prognosis, and risk stratification in PH population [1, 30]. A recent study demonstrated the prognostic significance of FWLS/SPAP ratio in comparison to other echocardiographic parameters in PAH in multivariate analysis [31].

Relationship between RHC parameters and RVMW indices

The correlation analysis revealed good associations between RVMW parameters and invasive hemodynamic parameters obtained from RHC. This study is the first to test the highest number of correlations between RVMW indexes and multiple invasive parameters. Of all the RVMW parameters, RVGWW and RVGWE were the ones that revealed more significant correlations with invasive indexes, both demonstrating significant correlations with mean PAP, PVR, CO, CI, SvO2, SV, SVi, RVSW and RVSWi. RVGWE also correlates significantly with RA pressure, whereas RVGWW correlates with PAPI, as well as RVGWI and RVGCW.

RVGCW and RVGWW increase as mean PAP, PVR, RVSW and RVSWI also increase, and the opposite for RVGWE. Mean PAP and PVR reflect the severity of PH. The rise in RVGWW alongside these parameters suggests that as PH worsens and the workload on the RV increases [24], as exihibited by increased RVGCW, there is a corresponding increase in the energy expended by the RV. This additional energy is not effectively converted into useful work, resulting in higher RVGWW and reduced RVGWE [32, 33]. Similarly, the correlation with RVSW and RVSWI further underlines the impact of increased hemodynamic load on RV function. This suggests that as the RV works harder to overcome increased afterload in PH, a greater proportion of its mechanical energy is dissipated as wasted work. RVSW and RVSWI are strongly correlated with myocardial oxygen consumption and indicate the ventricular work required to produce hydraulic energy and generate forward stroke work [34]. Several studies on patients with pre-capillary PH have found that decreased RVSWI is independently associated with increased mortality [13, 35].

Contrarily, both RVGCW and RVGWW increase as CO and CI decrease, and the opposite for RVGWE. RVMW also integrates RV desynchrony and post-systolic shortening into its non-invasive estimate of RV function, through the synchronization of cardiac cycle timing with RV GLS [16]. Any myocardial lengthening occurring during systole and shortening during isovolumic relaxation are recorded as RVGWW and do not contribute to RVGCW. Despite this, our data suggests as CO and CI decrease, the RV attempts to compensate by increasing RVGCW. However, this compensation is insufficient, leading to a disproportionate increase in RVGWW relative to RVGCW, ultimately resulting in a decrease in RVGWE along with the decline in CO and CI. Likewise, since SvO2 reflects CO and CI [1], it correlates with RVMW indexes in a similar fashion. SV and SVi provide an indirect estimate of RV contractility [36]. This may explain why there’s a negative correlation between these invasive indexes and RVGWW and a positive one with RVGWE. Finally, what is also significant in our work is the correlation between RVMW indexes with CI, SVI, RA pressure, SvO2 and NT-proBNP - which are considered as hallmarks in prognostication of patients with PH [1].

The lack of correlation of some RVMW indexes and invasive parameters is noteworthy and merits consideration. The lack of correlation can be influenced by methodological factors such as measurement variability, sample size, and study design. It’s possible that the small study population did not fully capture the range of hemodynamic variations necessary to detect significant correlations between these parameters.

The use of invasive measurements as a surrogate of afterload

The choice to utilize invasive measurements of PAP instead of estimates obtained by TTE warrants discussion. While echocardiography-based estimates of pulmonary pressures are valuable in many clinical settings, their reliability can be compromised, especially in patients with suboptimal imaging windows or complex hemodynamics [37]. In some patients, obtaining accurate estimates of SPAP may be challenging because there isn’t measurable tricuspid regurgitant jet or because have severe TR that underestimate SPAP [14, 38]. In our control group, for example, three of 8 patients did not present sufficient TR jet for SPAP estimation by TTE. It’s also challenging to estimate diastolic PAP in the absence of pulmonary regurgitation. Due to these reasons, in our study, we considered that the use of invasive measurements was necessary for robust comparisons. Additionally, invasive measurements offer direct assessment of pulmonary hemodynamics, providing a gold standard for validation and calibration of non-invasive parameters [1]. Finally, as shown in this study and in previous published work, RHC is a safe technique in experienced centers [39].

Utility

Echocardiographic assessment of RV function remains challenging due to the intrinsic right ventriculo-arterial relationship and complex ventricular anatomy. By incorporating both contractile function and afterload, RVMW provides a less load dependent index of ventricular performance [19]. In the future, the non-invasive evaluation of RVMW may have the potential to enhance echocardiographic monitoring of patients with precapillary PH. The correlation between RVMW echo-derived indexes and invasive prognostic parameters [1] suggests that these novel TTE measurements could be valuable tools for risk stratification in these patients. Moreover, RV GLS have been independently associated with clinical deterioration and all-cause mortality in patients with group I PH [3], implying a possible role for the monitoring of these patients with speckle-tracking echocardiography. However, simultaneous evaluation of indexes of RVMW may contextualize any changes in RV GLS. Unlike RV GLS, TAPSE, and FAC, these novel indexes not only reflect function but also assess RV performance by considering afterload and synchrony [11, 17]. A study analyzing patients that underwent RV pressure-conductance catheterization demonstrated that not only myocardial work index strongly correlates with the gold-standard assessment of RV contractility, but also effectively illustrates the increase in the RV’s contractile state when right ventriculo-arterial uncoupling is present [20]. Hence, RVMW, namely myocardial work index, may serve as an integrative index of load-independent contractility to monitor treatment response and disease progression in patients with RV hemodynamic overload.

Overall, the findings of this study contribute to advancing our understanding of RV function in PH. However, further research is warranted to validate these findings and explore the utility of RVMW. By building upon existing literature and integrating multidimensional data from echocardiography and invasive hemodynamics, future studies can further elucidate the role of RVMW parameters in guiding therapeutic strategies and improving prognostication in PH and other cardiovascular conditions. Our findings serve as one of the earliest demonstrations of the off-label feasibility of using software originally designed for assessing the myocardial work of the LV in evaluating the RV. In the future, a total non-invasive method should be feasible, using estimates of pulmonary pressure echo-derived.

Limitations

The present study had several limitations:

This study, although based in prospective registries, is limited by its single-centre observational design. Only a small number of patients were evaluated, therefore, larger studies will be required to define the normal values of RVMW and to confirm its clinical utility for patients with PH. Another important limitation is that the commercial software required for the measurement of RVMW is only provided by a single-vendor and was specifically designed for the assessment of the myocardial work of the LV.

Another limitation is the different age and gender distribution between groups, as previous studies have shown that certain RVMW indexes can be influenced by these factors [40].

The limited number of patients precluded us from investigating the association between RVMW parameters and survival. The two groups were derived from different registries collected at different time points, introducing variability and potential biases and could impact the comparability of the groups. Further research is warranted to validate these findings in larger cohorts and explore the potential clinical applications of RVMW parameters in guiding therapeutic interventions and prognostication in PH and other diseases of the right heart.

Conclusion

New methods to evaluate RV function are crucial in patients with RV pressure overload, since conventional echocardiographic parameters do not perform well. This study demonstrated the feasibility and clinical relevance of assessing RVMW using TTE and integrating pressure values RHC. Patients with pre-capillary PH present significantly higher RVGWI, RVGCW and RVGWW and lower RVGWE than patients without PH. Echocardiographic RVMW-derived indexes show strong correlation with invasive pulmonary arterial pressure and resistance, CO and CI, SvO2, invasive RV function indexes and NT-proBNP. By integrating non-invasive imaging with invasive hemodynamic data, clinicians can obtain a comprehensive understanding of RV performance.