Clinical value of echocardiographic Doppler-derived right ventricular dp/dt in patients with pulmonary arterial hypertension

Importance of the Mean Rate of Pressure Change of the Pulmonary Artery (dP/dt mean PA) in Patients with Pulmonary Arterial Hypertension

Background  Pulmonary arterial hypertension (PAH) is a rare disease of cardiopulmonary circulation characterized by elevated pressure in the pulmonary artery. The right-heart catheter is the gold standard for diagnosis, but there is interest in identifying additional prognostic indicators. The aim of this study was to examine the importance of the rate of pressure change of the pulmonary artery (dP/dt mean PA) in patients with PAH. Methods  We retrospectively analyzed data from 142 patients with PAH (exclusively clinical group 1) and examined the statistical correlation of dP/dt mean PA with vascular, right ventricular, and clinical parameters. Data was collected mostly from the right heart catheterization and the transthoracal echocardiography at presentation. Results  dP/dt mean PA showed a significant correlation with systolic pressure of the pulmonary artery ( n = 142, R ²  = 56%, p  < 0.001), pulmonary vascular resistance ( n  = 142, R ²  = 51%, p  < 0.001), the rate of pressure change in the right ventricle ( n  = 142, R ²  = 53%, p  < 0.001), and the right ventricular fractional area change ( n  = 110, R ²  = 51%, p  < 0.001). Receiver operating characteristic curve analysis showed that dP/dt mean PA had the highest prognostic value in predicting increase in the 6-minute walk test and decrease in the N-terminal-probrain natriuretic peptide after the initiation of PAH therapy, with an area under the curve of 0.73. Conclusion  Our findings suggest that dP/dt mean PA may be a useful prognostic indicator in the treatment of patients with PAH, and further research is warranted to validate this parameter.

Predicting the Severity and Outcome of Persistent Pulmonary Hypertension of the Newborn Using New Echocardiography Parameters

OBJECTIVE

To examine echocardiographic (ECHO) parameters correlation with clinical severity indices, Alveolar- arterial gradient (A-a gradient), oxygenation index (OI) and clinical outcomes in newborns with persistent pulmonary hypertension of the newborn (PPHN).

STUDY DESIGN

Retrospective cohort study of 67 subjects, >35 weeks' gestation with the diagnosis of PPHN admitted to the University of Kentucky neonatal intensive care unit (NICU) between September 2014 and December 2016.

RESULTS

High left ventricular end-systolic eccentricity index (EIs) correlates with the overall clinical severity of PPHN as it is associated with higher A-a gradient and OI (p=0.0003 and p<0.0001, respectively). Elevated EIs was also predictive for the use of inhaled nitric oxide (iNO) and extracorporeal membrane oxygenation (ECMO) (p=0.0004 and p<0.0001, respectively). EIs value of >1.38 provides cutoff value as an objective marker for the need for ECMO.

CONCLUSION

EIs can be used to assess clinical severity and outcomes and should be reported routinely. Further studies are warranted to confirm these results.

Pertussis Toxin Promotes Pulmonary Hypertension in an Infant Mouse Model of Bordetella pertussis Infection

Pertussis, caused by Bordetella pertussis, is a reemerging disease that can produce severe disease manifestations in infants, including pulmonary hypertension (PH). B. pertussis-induced PH is a major risk factor for infection-induced death, but the molecular mechanisms promoting PH are unknown and there is no effective treatment. We examined B. pertussis-induced PH in infant and adult mouse models of pertussis by Fulton index, right heart catheterization, or Doppler echocardiogram. Our results demonstrate that B. pertussis-induced PH is age related and dependent on the expression of pertussis toxin by the bacterium. Hence, pertussis toxin-targeting treatments may ameliorate PH and fatal infant infection.

Echocardiography in Pulmonary Arterial Hypertension: Comprehensive Evaluation and Technical Considerations

Pulmonary arterial hypertension (PAH) is a rare, progressive disease in which there is a persistent, abnormal increase in pulmonary artery pressure. Symptoms of pulmonary hypertension are nonspecific and mainly associated with progressive right ventricular failure. The diagnosis of PAH is a multistep process and often requires the skillful use of several tests. The gold standard for the diagnosis of PAH is hemodynamic testing. Echocardiography currently plays an important role in the diagnostic algorithm of PAH as it is minimally invasive and readily available. Moreover, many echocardiographic parameters are closely related to pulmonary hemodynamics. It allows assessment of the right heart′s structure and function, estimation of the pressure in the right ventricle, right atrium, and pulmonary trunk, and exclusion of other causes of elevated pulmonary bed pressure. Echocardiographic techniques are constantly evolving, and recently, measurements made using new techniques, especially 3D visualization, have become increasingly important. In echocardiographic assessment, it is crucial to know current guidelines and new reports that organize the methodology and allow standardization of the examination. This review aims to discuss the different echocardiographic techniques used to evaluate patients with PAH.

The Growing Role of Echocardiography in Pulmonary Arterial Hypertension Risk Stratification: The Missing Piece

Pulmonary arterial hypertension (PAH) is a rare, progressive disease with a poor prognosis. The pathophysiologic model is mainly characterized by an afterload mismatch in which an increased right ventricle afterload, driven by increased pulmonary vascular resistance (PVR), leads to right heart failure. International guidelines recommend optimization of treatment based on regular risk assessments to achieve or maintain a low-risk status. Current risk scores are based on a multi-modality approach, including demographic, clinical, functional, exercise, laboratory, and hemodynamic parameters, which lack significant echocardiographic parameters. The originality of echocardiography relies on the opportunity to assess in a non-invasive way a physiologically meaningful combination of easy to measure variables tightly related to right ventricle adaptation/maladaptation to increased afterload, the main determinant of a patient's prognosis. Echo-derived morphological and functional parameters have been investigated in PAH, proving to have prognostic relevance. Different therapeutic strategies proved to have different effects in reducing PVR. An upfront combination of drugs, including a parenteral prostacyclin, has shown to be associated with right heart reverse remodeling in a greater proportion of patients than other treatment strategies as a function of PVR reduction. Adding echocardiographic data to current risk scores would allow better identification of right ventricle (RV) adaptation in PAH patients' follow-up. This additional information would allow better stratification of the patient, leading to optimized and personalized therapeutic management.

The dangerous and contradictory prognostic significance of PVR<3WU when TAPSE<16mm in postcapillary pulmonary hypertension

Aims

In 2019, pulmonary vascular resistance (PVR) < 3WU was adopted to stratify patients at low risk in pulmonary hypertension due to left heart disease (PH‐LHD) as well those with isolated PH‐LHD. We sought to evaluate whether supervised machine learning with decision tree analysis, which provides more information than Cox Proportional analysis by forming a hierarchy of multiple covariates, confirms this risk stratification.

Methods and results

Two hundred two consecutive patients (mean age: 69 ± 11 years, female: 42%) with mean pulmonary artery pressure ≥ 20 mmHg and wedge pressure > 15 mmHg were recruited. Transpulmonary pressure gradient ⩾̸ 12 mmHg, PVR ⩾̸ 3WU, diastolic pressure gradient ⩾̸ 7 mmHg, pulmonary arterial capacitance < 1.1 mL/mmHg, tricuspid annular plane systolic excursion (TAPSE) < 16 mm, peak systolic tissue Doppler velocity < 10 cm/s, right ventricular end‐diastolic area ⩾̸ 25 cm² were the seven categorical values entered into the model due to their prognostic significance in PH. We used the chi‐squared automatic interaction detection method to predict mortality. Each node and branch were compared using survival analysis at 6‐year follow‐up. Mean pulmonary artery pressure, wedge pressure, cardiac index, and PVR were 40.3 ± 10.0 mmHg, 22.3 ± 7.1 mmHg, 2.9 ± 0.8 L/min/m², and 3.6 ± 2.1WU, respectively. Among the seven dichotomous, TAPSE was first selected following by PVR. Compared with patients with PVR < 3WU and TAPSE ⩾̸ 16 mm, patients with PVR ⩾̸ 3WU and TAPSE ⩾̸ 16 mm, or patients with PVR ⩾̸ 3WU and TAPSE<16 mm had significantly increased mortality, HR = 3.0, 95% CI = [1.4–6.4], P = 0.006 and HR = 3.3, 95% CI = [1.6–6.9], P = 0.002, respectively, while patients with PVR < 3WU and TAPSE < 16 mm exhibited the worst prognosis, HR = 7.2, 95% CI = [3.3–15.9], P = 0.0001.

Conclusions

Used for solving regression and classification problems, decision tree analysis confirms that PVR and TAPSE have to be analysed together in PH‐LHD and revealed the dangerous and contradictory prognostic significance of PVR < 3WU when TAPSE<16 mm.

Anatomic Relationship of the Complex Tricuspid Valve, Right Ventricle, and Pulmonary Vasculature: A Review

Importance

Severe functional or secondary tricuspid regurgitation (TR) is associated with poor long-term outcomes in natural history studies as well as specific disease states. An understanding of the physiologic causes of the TR is lacking precluding a systematic approach to treatment.

Observations

The complex anatomic relationship between the tricuspid valve apparatus and structure of the right side of the heart lends insight into the functional changes seen with secondary TR. The association of these changes with changes in pulmonary vascular hemodynamics can lead to a cascade of events that result in disease progression.

Conclusions and Relevance

Appreciating the role of pulmonary vascular hemodynamics on right ventricular and tricuspid valve morphology and function improves our understanding of the pathophysiology of secondary TR. The limitations of current therapeutic approaches for secondary TR have stimulated interest in improving outcomes with this morbid disease. Changes in timing or approach to intervention require a more comprehensive understanding of the pathophysiology.

Assessment of Right Ventricular Function in the Research Setting: Knowledge Gaps and Pathways Forward. An Official American Thoracic Society Research Statement

BACKGROUND

Right ventricular (RV) adaptation to acute and chronic pulmonary hypertensive syndromes is a significant determinant of short- and long-term outcomes. Although remarkable progress has been made in the understanding of RV function and failure since the meeting of the NIH Working Group on Cellular and Molecular Mechanisms of Right Heart Failure in 2005, significant gaps remain at many levels in the understanding of cellular and molecular mechanisms of RV responses to pressure and volume overload, in the validation of diagnostic modalities, and in the development of evidence-based therapies.

METHODS

A multidisciplinary working group of 20 international experts from the American Thoracic Society Assemblies on Pulmonary Circulation and Critical Care, as well as external content experts, reviewed the literature, identified important knowledge gaps, and provided recommendations.

RESULTS

This document reviews the knowledge in the field of RV failure, identifies and prioritizes the most pertinent research gaps, and provides a prioritized pathway for addressing these preclinical and clinical questions. The group identified knowledge gaps and research opportunities in three major topic areas: 1) optimizing the methodology to assess RV function in acute and chronic conditions in preclinical models, human studies, and clinical trials; 2) analyzing advanced RV hemodynamic parameters at rest and in response to exercise; and 3) deciphering the underlying molecular and pathogenic mechanisms of RV function and failure in diverse pulmonary hypertension syndromes.

CONCLUSIONS

This statement provides a roadmap to further advance the state of knowledge, with the ultimate goal of developing RV-targeted therapies for patients with RV failure of any etiology.

Prognostic relevance of the right ventricular myo-mechanical index (RV-MMI) in patients with precapillary pulmonary hypertension

Objective

The aim of the prospective New-RV study was to evaluate a parameter for non-invasive quantification of right ventricular (RV) dysfunction in patients with precapillary pulmonary hypertension (PH) that yields prognostic information and is applicable in daily clinical routine.

Methods

Sixty-five consecutive patients with precapillary PH under guideline conform therapy (43 women, 22 men) underwent clinical assessment, serological testing, as well as a comprehensive transthoracic echocardiography including strain imaging and a detailed assessment of RV haemodynamics.

Results

The mean follow-up time was 844 days. Sixteen patients died during clinical follow-up. Right ventricular myo-mechanical index (RV-MMI) was calculated by right atrial size, mean RV pressure gradient and strain imaging of the RV free wall, and was measurable in all examinations. RV-MMI was tested for its diagnostic accuracy (sensitivity of 88% and specificity of 73% for an optimal cut-off value of ≤0.31 mm Hg^*%; area under the curve=0.85), as well as its predictive value (HR=3.3, 95% CI 1.6 to 7.0, p<0.001), and was compared in detail with established parameters. RV-MMI and N-terminal pro-brain natriuretic peptide (NTproBNP)were independent predictors of survival (HR=2.9, 95% CI 1.4 to 6.2, p=0.006; and HR=2.6, 95% CI 1.5 to 4.6, p=0.001, respectively).

Conclusion

In a cohort of patients with precapillary PH, the RV-MMI differentiates the outcome of patients better than other available non-invasive parameters of RV function by preload and afterload adjusted quantification.

Trial registration number

NCT01230294.

Cardiac Ventricular Contractile Responses to Chronically Increased Afterload Secondary to Right Ventricular Outflow Obstruction in Patients With Tetralogy of Fallot

We examined the adaptive mechanism of the pulmonary ventricle (PV) in response to increased afterload secondary to pulmonary stenosis in tetralogy of Fallot (TOF, n = 47) and congenitally corrected transposition of the great arteries (cCTGA, n = 18), where the PV is morphologically different. We also elucidated the effects of such adaptation on systemic ventricular (SV) function. PV contractility, assessed by dp/dt_max, showed significant positive correlations with PV pressure (r = 0.82, p <0.01 for TOF and r = 0.78, p <0.01 for cCTGA) and pulmonary-to-systemic ventricular pressure ratio (r = 0.70, p <0.01 for TOF and r = 0.76, p <0.01 for cCTGA) in patients with both TOF and cCTGA. Notably, the slopes of these correlations were significantly higher in cCTGA than in TOF (p <0.01), suggesting enhanced contractile responses in cCTGA. Moreover, SV dp/dt_max showed significant positive correlations with PV dp/dt_max in patients with both TOF and cCTGA (r = 0.67, p <0.01 and r = 0.61, p <0.01, respectively), indicating positive ventricular-ventricular interaction. In this relationship, the slopes of correlations were significantly higher in TOF than in cCTGA (p = 0.024). These results, indicating different behaviors of PV contractile physiology and its interaction with the SV, may have important therapeutic implications when considering medical, catheter, and surgical interventions for pulmonary stenosis in these diseases. The results may also offer the potential for a new approach for improvement of prognosis, especially in cCTGA.

Echocardiographic right ventricular function correlations with cardiac catheterisation data in biventricular congenital heart patients

BACKGROUND

Newer echocardiographic techniques may allow for more accurate assessment of right ventricular function. Adult studies have correlated these echocardiographic measurements with invasive data, but minimal data exist in the paediatric congenital heart population. The purpose of this study was to evaluate echocardiographic measurements that correlate best with right ventricular systolic and diastolic catheterisation parameters.

METHODS

Patients with two-ventricle physiology who underwent simultaneous echocardiogram and cardiac catheterisation were included in this study. Right ventricular systolic echocardiographic data included fractional area change, displacement, tissue Doppler imaging s' wave, global longitudinal strain, and strain rate s' wave. Diastolic echocardiographic data included tricuspid E and A waves, tissue Doppler imaging e' and a' waves, and strain rate e' and a' waves. E/tissue Doppler imaging e', tissue Doppler imaging e'/tissue Doppler imaging a', E/strain rate e', and strain rate e'/strain rate a' ratios were also calculated. Catheterisation dP/dt was used as a marker for systolic function and right ventricular end-diastolic pressure for diastolic function.

RESULTS

A total of 32 patients were included in this study. The median age at catheterisation was 3.1 years (0.3-17.6 years). The DP/dt was 493±327 mmHg/second, and the right ventricular end-diastolic pressure was 7.7±2.4 mmHg. There were no significant correlations between catheterisation dP/dt and systolic echocardiographic parameters. Right ventricular end-diastolic pressure correlated significantly with strain rate e' (r=-0.4, p=0.02), strain rate a' (r=-0.5, p=0.03), and E/tissue Doppler imaging e' (r=0.4, p=0.04).

CONCLUSION

Catheterisation dP/dt did not correlate with echocardiographic measurements of right ventricular systolic function. Strain rate and tissue Doppler imaging analysis significantly correlated with right ventricular end-diastolic pressure. These values should be further studied to determine whether they may be used as an alternative method to estimate right ventricular end-diastolic pressure in this patient population.

Assessment of pulmonary arterial compliance evaluated using harmonic oscillator kinematics

We hypothesized that K_PA, a harmonic oscillator kinematics-derived spring constant parameter of the pulmonary artery pressure (PAP) profile, reflects PA compliance in pediatric patients. In this prospective study of 33 children (age range = 0.5–20 years) with various cardiac diseases, we assessed the novel parameter designated as K_PA calculated using the pressure phase plane and the equation K_PA = (dP/dt_max)²/([Pmax – Pmin])/2)², where dP/dt_max is the peak derivative of PAP, and Pmax – Pmin is the difference between the minimum and maximum PAP. PA compliance was also calculated using two conventional methods: systolic PA compliance (sPAC) was expressed as the stroke volume/Pmax – Pmin; and diastolic PA compliance (dPAC) was determined according to a two-element Windkessel model of PA diastolic pressure decay. In addition, data were recorded during abdominal compression to determine the influence of preload on K_PA. A significant correlation was observed between K_PA and sPAC (r = 0.52, P = 0.0018), but not dPAC. Significant correlations were also seen with the time constant (τ) of diastolic PAP (r = −0.51, P = 0.0026) and the pulmonary vascular resistance index (r = −0.39, P = 0.0242). No significant difference in K_PA was seen between before and after abdominal compression. K_PA had a higher intraclass correlation coefficient than other compliance and resistance parameters for both intra-observer and inter-observer variability (0.998 and 0.997, respectively). These results suggest that K_PA can provide insight into the underlying mechanisms and facilitate the quantification of PA compliance.

Echocardiography Combined With Cardiopulmonary Exercise Testing for the Prediction of Outcome in Idiopathic Pulmonary Arterial Hypertension

BACKGROUND

Right ventricular (RV) function is a major determinant of exercise intolerance and outcome in idiopathic pulmonary arterial hypertension. The aim of the study was to evaluate the incremental prognostic value of echocardiography of the right ventricle and cardiopulmonary exercise testing (CPET) on long-term prognosis in these patients.

METHODS

One hundred and thirty treatment-naïve patients with idiopathic pulmonary arterial hypertension were enrolled and prospectively followed. Clinical worsening (CW) was defined by a reduction in 6-min walk distance plus an increase in functional class, or nonelective hospitalization for PAH, or death. Baseline evaluation included clinical, hemodynamic, echocardiographic, and CPET variables. Cox regression modeling with c-statistic and bootstrapping validation methods were done.

RESULTS

During a mean period of 528 ± 304 days, 54 patients experienced CW (53%). Among demographic, clinical, and hemodynamic variables at catheterization, functional class and cardiac index were independent predictors of CW (model 1). With addition of echocardiographic and CPET variables (model 2), peak O₂ pulse (peak V˙o₂/heart rate) and RV fractional area change (RVFAC) independently improved the power of the prognostic model (area under the curve, 0.81 vs 0.66, respectively; P = .005). Patients with low RVFAC and low O₂ pulse (low RVFAC + low O₂ pulse) and high RVFAC + low O₂ pulse showed a 99.8 and 29.4 increase in the hazard ratio, respectively (relative risk, 41.1 and 25.3, respectively), compared with high RVFAC + high O₂ pulse (P = .0001).

CONCLUSIONS

Echocardiography combined with CPET provides relevant clinical and prognostic information. A combination of low RVFAC and low O₂ pulse identifies patients at a particularly high risk of clinical deterioration.

Echocardiography in pulmonary hypertension

PURPOSE OF REVIEW

Pulmonary hypertension is a progressive disease of the pulmonary vasculature characterized by increased vascular resistance and pressure overload of the right ventricle. This review aims to describe the diagnostic and prognostic role of echocardiography in pulmonary hypertension with particular consideration of relative strengths, weaknesses and new advances.

RECENT FINDINGS

Although right heart catheterization (RHC) remains the gold standard, echocardiography represents an accessible and feasible real-world tool for screening, differential diagnostic, follow-up assessments and risk stratification in pulmonary hypertension. In the context of clinical scenario and multimaging approach, echocardiography provides accurate measurements of pulmonary haemodynamics, either at rest and/or during exercise, and is particularly useful in ruling out secondary causes of pulmonary hypertension and/or detecting preclinical stages. The use of advanced noninvasive imaging techniques may provide additional information in assessing right heart structure and function.

SUMMARY

Advances in echocardiography and the multimodality imaging approach continue to provide new understandings and opportunities for the study of the right heart-pulmonary circulation unit in pulmonary hypertension.

Functional and molecular factors associated with TAPSE in hypoxic pulmonary hypertension

Adaptation of the right ventricle (RV) to increased afterload is crucial for survival in pulmonary hypertension (PH), but it is challenging to assess RV function and identify associated molecular mechanisms. The aim of the current study was to analyze the relationship between invasive and noninvasive parameters of RV morphology and function and associated molecular changes. The response of mice to normobaric hypoxia was assessed by hechocardiography, invasive hemodynamics, and histological and molecular analyses. Plasma levels of possibly novel markers of RV remodeling were measured by ELISA in patients with idiopathic pulmonary arterial hypertension (IPAH) and matched healthy controls. Chronic hypoxia-induced PH was accompanied by significantly decreased tricuspid annular plane systolic excursion (TAPSE) and unchanged RV contractility index and tau. RV hypertrophy was present without an increase in fibrosis. There was no change in α- and β-major histocompatibility class or natriuretic peptides expression. Comparative microarray analysis identified two soluble factors, fibroblast growth factor-5 (FGF5) and interleukin-22 receptor alpha-2 (IL22RA2), as being possibly associated with RV remodeling. We observed significantly higher plasma levels of IL22RA2, but not FGF5, in patients with IPAH. Hypoxic pulmonary hypertension in a stage of RV remodeling with preserved systolic function is associated with decreased pulmonary vascular compliance, mild diastolic RV dysfunction, and significant decrease in TAPSE. Subtle gene expression changes in the RV vs. the left ventricle upon chronic hypoxia suggest that the majority of changes are due to hypoxia and not due to changes in afterload. Increased IL22RA2 levels might represent a novel RV adaptive mechanism.

The Role of Echocardiography in the Evaluation of Pulmonary Arterial Hypertension

The evaluation of pulmonary arterial hypertension (PAH) requires a multimodality approach that combines invasive and noninvasive imaging studies to ensure accurate diagnosis and classification. Given the complexity of the hemodynamic relationships between the left heart, pulmonary circulation, and right heart, the diagnosis of PAH is often a challenging task. Right heart catheterization is the gold standard for diagnosis, providing the hemodynamic information that defines the disease. Nonetheless, echocardiography continues to be a valuable tool in the approach to the patient with suspected PAH. Echocardiographic assessment generates a wealth of information about the response of the right heart to elevated pulmonary pressures and provides essential diagnostic and prognostic data to the clinician. Numerous measurements can be used to identify alterations in right heart morphology, pressure, and function; although each variable in isolation may have little utility, meaningful information is revealed when multiple parameters are considered together. In this article, we will review the echocardiographic measurements employed in assessment of the right heart and seek to clarify the role of echocardiography in the diagnostic workup of PAH.