Echocardiographic predictors of mortality in patients with pulmonary hypertension and cardiopulmonary comorbidities

The Role of Echocardiography in the Diagnosis and Prognosis of Pulmonary Hypertension

The right heart catheterisation constitutes the gold standard for pulmonary hypertension (PH) diagnosis. However, echocardiography remains a reliable, non-invasive, inexpensive, convenient, and easily reproducible modality not only for the preliminary screening of PH but also for PH prognosis. The aim of this review is to describe a cluster of echocardiographic parameters for the detection and prognosis of PH and analyse the challenges of echocardiography implementation in patients with suspected or established PH. The most important echocardiographic index is the calculation of pulmonary arterial systolic pressure (PASP) through the tricuspid regurgitation (TR). It has shown high correlation with invasive measurement of pulmonary pressure, but several drawbacks have questioned its accuracy. Besides this, the right ventricular outflow track acceleration time (RVOT-AT) has been proposed for PH diagnosis. A plethora of echocardiographic indices: right atrial area, pericardial effusion, the tricuspid annular plane systolic excursion (TAPSE), the TAPSE/PASP ratio, tricuspid annular systolic velocity (s'), can reflect the severity and prognosis of PH. Recent advances in echocardiography with 3-dimensional right ventricular (RV) ejection fraction, RV free wall strain and right atrial strain may further assist the prognosis of PH.

Novel Echocardiographic Algorithm for Right Ventricular Mass Quantification: Cardiovascular Magnetic Resonance and Clinical Prognosis Validation

BACKGROUND

Right ventricular hypertrophy (RVH) provides a key remodeling index alterable by pulmonary hypertension. Although echocardiography commonly integrates linear wall thickness and chamber dimensions to quantify left ventricular remodeling, the utility of an equivalent right ventricular (RV)-based approach is unknown.

METHODS

This was a retrospective analysis of 200 patients undergoing transthoracic echocardiography and cardiac magnetic resonance (CMR) within 30 days (median = 3 days; interquartile range, 15 days), stratified by echocardiography-quantified pulmonary artery systolic pressure (<35, 35 to <55, 55 to <75, or ≥75 mm Hg). Echocardiographic assessment included RV linear dimensions in parasternal long-axis and apical four-chamber views and wall thicknesses in parasternal long-axis, four-chamber, and subcostal views. Subcostal wall thickness was integrated with chamber diameters to calculate RV mass, which was tested in relation to CMR-quantified RV mass and all-cause mortality.

RESULTS

Echocardiography-based quantification of all linear dimensions was feasible in 95% of patients (190 of 200). RV wall thicknesses in all orientations increased in relation to pulmonary artery systolic pressure (P < .001) and was greater among patients with, versus those without, CMR-evidenced RVH (P < .001 for all). Correlations between echocardiography and CMR were greatest for RV basal diameter (r = 0.73), RV subcostal wall thickness (r = 0.71), and global RV mass (r = 0.82; P < .001 for all). Echocardiography-derived global RV mass cutoffs were established in a derivation cohort and tested in a validation cohort. Results demonstrated good sensitivity and specificity (75.5% and 74.0%, respectively) in relation to CMR-quantified RVH. During follow-up (median, 4.2 years), 18% of patients (n = 36) died. Echocardiography-evidenced RVH (hazard ratio, 1.98; 95% CI, 1.09-3.88; P = .048) conferred similar mortality risk compared with RVH on CMR (hazard ratio, 2.41; 95% CI, 1.22-4.78; P = .01).

CONCLUSIONS

Echocardiography-quantified RV parameters provide a robust index of RV afterload. Global RV mass calculated using a novel echocardiographic formula based on readily available linear indices yields good diagnostic performance for CMR-evidenced RVH and confers increased mortality risk.

A prediction model of simple echocardiographic variables to screen for potentially correctable shunts in adult patients with pulmonary arterial hypertension associated with atrial septal defects: a cross-sectional study

During the routine follow-up of adult patients with pulmonary arterial hypertension associated with atrial septal defects (ASD-PAH), the suitability of shunt closure depends on the invasive right heart catheterization (RHC). It is difficult to grasp the timing of RHC shunt closure for moderate-severe PAH. This retrospective cross-sectional study was designed to investigate which echocardiographic variables are related to pulmonary vascular resistance (PVR) in adult ASD-PAH patients and propose a method using echocardiographic variables to screen for patients where shunt closure is suitable. A total of 139 adult ASD-PAH patients with a PASP ≥ 60 mmHg measured by transthoracic echocardiogram (TTE) were included in this study. All RHCs were performed within a week after TTE. The Correctable shunt was defined as PVR ≤ 4.6 wood units (WU). Multivariate regressions were performed with echocardiographic variables. The nomogram of prediction model was constructed by the predictors of PVR ≤ 4.6 WU by multivariate logistic regression analysis. Multivariate linear regression revealed that TAPSE (tricuspid annular plane systolic excursion)/pulmonary artery systolic pressure (PASP) measured by TTE was negatively associated with PVR (β per SD: - 1.84, 95%CI - 2.62, - 1.06). Multivariate logistic regression showed that TAPSE/PASP and pulmonary valve (PV) peak velocity were positively associated with a potentially correctable shunt (PVR ≤ 4.6 WU) (OR per SD: 2.38, 95%CI 1.34, 4.25, and OR per SD: 2.67, 95%CI 1.26, 5.64, respectively). In receiver operating characteristic analysis, the TAPSE/PASP + PV peak velocity combined model achieved the best performance (AUC: 0.8584, sensitivity: 83.33%, specificity: 72.16%). Internal verification showed stable performance (AUC: 0.8591, sensitivity: 88.10%, specificity: 68.04%). The net benefit of this model was greater than other models when it came to a wide range probability threshold in decision curve analysis. TAPSE/PASP + PV the peak velocity model may have great value in predicting adult ASD-PAH patients with operability potential, which could help clinicians make the treatment decision for follow-up patients.

Sex Differences in Right Ventricular Dysfunction: Insights From the Bench to Bedside

There are inherent distinctions in right ventricular (RV) performance based on sex as females have better RV function than males. These differences are magnified and have very important prognostic implications in two RV-centric diseases, pulmonary hypertension (PH), and arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D). In both PH and ARVC/D, RV dysfunction results in poor patient outcomes. However, there are no currently approved therapies specifically targeting the failing RV, an important unmet need for these two life-threatening disorders. In this review, we highlight human data demonstrating divergent RV phenotypes in healthy, PH, and ARVC/D patients based on sex. Furthermore, we discuss the links between estrogen (the female predominant sex hormone), testosterone (the male predominant sex hormone), and dehydroepiandrosterone (a precursor hormone for multiple sex hormones in males and females) and RV function in both disorders. To provide potential mechanistic insights into sex differences in RV function, we review data that investigate how sex hormones combat or contribute to pathophysiological changes in the RV. Finally, we highlight the ongoing clinical trials in pulmonary arterial hypertension targeting estrogen and dehydroepiandrosterone signaling. Hopefully, a greater understanding of the factors that promote superior RV function in females will lead to novel therapeutic approaches to combat RV dysfunction in PH and ARVC/D.

Clinical Determinants and Prognostic Implications of Right Ventricular Dysfunction in Pulmonary Hypertension Caused by Chronic Lung Disease

Background

Patients with pulmonary hypertension caused by chronic lung disease (Group 3 PH) have disproportionate right ventricle (RV) dysfunction, but the correlates and clinical implications of RV dysfunction in Group 3 PH are not well defined.

Methods and Results

We performed a cohort study of 147 Group 3 PH patients evaluated at the University of Minnesota. RV systolic function was quantified using right ventricular fractional area change (RVFAC) and ⁺dP/dt_max/instantaneous pressure. Tau and RV diastolic stiffness characterized RV diastolic function. Multivariate linear regression was used to define correlates of RVFAC. Kaplan‐Meier and Cox proportional hazards analyses were used to examine freedom from heart failure hospitalization and death. Positive correlates of RVFAC on univariate analysis were pulmonary arterial compliance, cardiac index, and left ventricular diastolic dimension. Conversely, male sex, N‐terminal pro‐brain natriuretic peptide, heart rate, right atrial enlargement, mean pulmonary arterial pressure, and pulmonary vascular resistance were negative correlates. Male sex was the strongest predictor of lower RVFAC, after adjusting for pulmonary vascular resistance and pulmonary arterial compliance. When comparing sexes, males had lower RVFAC (26% versus 31%, P=0.03) both overall and for any given mean pulmonary arterial pressure and pulmonary vascular resistance value. Males exhibited a reduction in ⁺dP/dt_max/instantaneous pressure as pulmonary vascular resistance increased, whereas females did not. There were no sex differences in RV diastolic function. RV dysfunction (RVFAC <28%) was associated with increased risk of heart failure hospitalization or death (hazard ratio: 1.84, 95% CI: 1.04–3.10, P=0.035).

Conclusions

Male sex is associated with RV dysfunction in Group 3 PH, even after adjusting for RV afterload. RV dysfunction (RVFAC <28%) identifies Group 3 PH patients at risk for poor outcomes.

Prognostic significance of electrocardiographic right ventricular hypertrophy in the general population

BACKGROUND

Echocardiographically detected right ventricular hypertrophy (RVH) is associated with cardiovascular disease (CVD) and mortality. However, the prognostic significance of electrocardiographic (ECG)RVH criteria as predictors of poor outcomes in the general population is unclear.

METHODS

This study included 7857 participants (59.8 ± 13.4 years, 52.6% women) from the Third National Health and Nutrition Examination Survey. Sixteen different ECG-RVH criteria were created from digitally recorded and centrally processed electrocardiograms. All-cause mortality was ascertained using the National Death Index. Cox proportional hazards analysis was used to examine the association between baseline ECG-RVH criteria and all-cause mortality.

RESULTS

The prevalence of RVH varied widely among the criteria. The lowest ECG-RVH prevalence was 0.09% (using S > R in I, II, III) while the highest prevalence was 20.7% (using (R I + S III) - (S I + R III) < 15 mm). During a median follow-up of 14 years, 2812 deaths occurred. The mortality rate was highest among participants with ECG-RVH defined as R:S ratio V₅ < 0.75. In multivariable adjusted models, 9 out of the 16 ECG-RVH criteria were significantly associated with all-cause mortality. When ECG-RVH was defined as the presence of any ECG-RVH criteria, each additional ECG-RVH criteria was associated with 6% increased risk of all-cause mortality (HR (95% CI):1.06(1.03,1.10)).

CONCLUSIONS

There is a wide variation in the prevalence of ECG-RVH when different criteria are applied in the general population. However, the presence of ECG-RVH by most criteria regardless of prevalence was associated with poor prognosis suggesting that appropriate choice of criteria may enhance the utilization of these ECG markers in risk stratification.

Predictors of poor outcome in patients with pulmonary arterial hypertension: A single center study

OBJECTIVES

Pulmonary arterial hypertension (PAH) is a rare disorder with unfavorable prognosis despite implementation of specific PAH-oriented therapy. The aim of the study was to define predictors of poor prognosis in patients from one center treated according to the Polish National Health Fund program.

PATIENTS AND METHODS

Forty-seven consecutive patients (30 women; aged 39±17 years) with PAH diagnosis were enrolled to the study. Clinical assessment, laboratory measurements, electrocardiogram, echocardiography, 6-minute walk test, 24-hour Holter monitoring, cardiopulmonary exercise test and microvolt T-wave alternans test were performed during routine visits. Eight patients died during 2.6±1.7 years follow-up.

RESULTS

Parametrs which differentiated patients who died were brain natriuretic peptide (BNP) concentration ≥330 pg/mL (sensitivity 88%, specificity 92%, area under the ROC curve [AUC] 0.92); bilirubin concentration ≥1.2 mg/dL (sensitivity 88%, specificity 81%, AUC 0.85); right atrial area ≥21 cm2 (sensitivity 86%, specificity 69%, AUC 0.84), right ventricular (RV) dimension in the apical 4-chamber view ≥47 mm (sensitivity 86%, specificity 86%, AUC 0.85) and RV to left ventricular diastolic diameter ratio ≥1.5 (sensitivity 83%, specificity 84%; AUC 0.85). In multivariate analysis, independent predictors of mortality were higher BNP (p = 0.04) and bilirubin level (p = 0.03), higher right atrial area (p = 0.02) and lower tricuspid annular plane systolic excursion (p = 0.03).

CONCLUSIONS

In PAH patients treated with specific PAH-oriented therapy right atrial enlargement, impaired right ventricular systolic function, as well as increased BNP and bilirubin concentration was associated with an increased mortality risk.

Interleukin-6 is independently associated with right ventricular function in pulmonary arterial hypertension

BACKGROUND

An elevated serum level of interleukin-6 (IL-6) in pulmonary arterial hypertension (PAH) patients results in a greater symptom burden and increased mortality; however, the mechanisms underlying these observations remain unclear. Because both pre-clinical and clinical data associate elevated IL-6 levels with impaired cardiac function, we hypothesized that the adverse effects of IL-6 in PAH result, in part, from right ventricular (RV) dysfunction.

METHODS

We analyzed the relationship between IL-6 and RV function in 40 patients with PAH identified in our institutional PAH registry. Serum IL-6 levels was quantified by enzyme-linked immunoassay.

RESULTS

PAH patients had higher IL-6 levels than age- and gender-matched controls. Circulating IL-6 levels correlated inversely with echocardiography-based measures of RV function and RV-pulmonary artery (RV-PA) coupling. When dividing PAH patients by median IL-6 level, patients with higher IL-6 had significantly worse RV function (fractional area change [FAC] 23 ± 12% vs 38 ± 11%, tricuspid annular plane systolic excursion [TAPSE] 1.3 ± 0.3 cm vs 2.1 ± 0.5 cm), impaired RV-PA coupling (0.6 ± 0.5%/mm Hg vs 0.9 ± 0.5%/mm Hg), higher right atrial pressure (13 ± 7 mm Hg vs 9 ± 5 mm Hg), reduced cardiac index (2.0 ± 0.5 liters/min/m² vs 2.8 ± 1.0 liters/min/m²) and lower stroke volume (48 ± 20 ml vs 70 ± 28 ml). In contrast, the relationships between IL-6 and mean pulmonary artery pressure (mPAP), pulmonary vascular resistance (PVR) and pulmonary arterial compliance (PAC) were not significant. Finally, IL-6 was independently associated with RV function and RV-PA coupling after adjusting for static (PVR) and pulsatile (PAC) after-load on the RV.

CONCLUSIONS

Serum IL-6 levels are independently associated with RV function and RV-PA coupling in PAH. Patients with higher IL-6 levels have more severe RV dysfunction and diminished RV-PA coupling despite a comparable severity of pulmonary vascular disease.

Multispecialty pulmonary hypertension clinic in the VA

Pulmonary hypertension (PH) is often associated with cardiopulmonary co-morbidities, especially in older adults. A multispecialty approach to suspected PH is recommended, but there are few data on adherence to guidelines or outcomes in such patients. This was a single-center retrospective study of consecutively evaluated Veteran patients with suspected PH evaluated in a multispecialty PH clinic at a Veterans Affairs Medical Center, evaluating clinical characteristics, workup outcomes, and prognosis. The referral population (n = 125) was older (mean ± SD age = 73.6 ± 9.8 years) with frequent co-morbidities (e.g. COPD 60%) and obesity (mean ± SD BMI = 32.8 ± 8.1 kg/m²). Of 94 patients undergoing right heart catheterization (RHC), 73 (78%) had confirmed PH (mean pulmonary artery pressure ≥ 25 mmHg). PH was associated with higher BMIs (odds ratio [95% CI] for PH per 1 unit increase = 1.10 [1.02–1.19]) and brachial pulse pressures (odds ratio per 1 mmHg increase = 1.07 [1.02–1.13]). Seventy out of 73 were classifiable by WHO PH groupings. Most patients underwent guideline-recommended PH evaluation. Observed one-year mortality was high (17.8%); the one-year hospitalization rate was 34.2%. These results compare favorably to observations from the VA Clinical Assessment, Reporting, and Tracking cohort of Veterans with PH by RHC (19.1% and 60.9% one-year mortality and hospitalization rates, respectively). Multispecialty PH clinic evaluation revealed a high prevalence of co-morbidities in veterans with suspected PH; PH was prevalent in this referral population. PH patients had significant morbidity and mortality but supportive care measures improved following PH evaluation. Further prospective randomized study is needed to determine if a multispecialty clinic approach improves PH morbidity and mortality in veterans.

Pulmonary pulse wave transit time is associated with right ventricular-pulmonary artery coupling in pulmonary arterial hypertension

Pulmonary pulse wave transit time (pPTT), defined as the time for the systolic pressure pulse wave to travel from the pulmonary valve to the pulmonary veins, has been reported to be reduced in pulmonary arterial hypertension (PAH); however, the underlying mechanism of reduced pPTT is unknown. Here, we investigate the hypothesis that abbreviated pPTT in PAH results from impaired right ventricular-pulmonary artery (RV-PA) coupling. We quantified pPTT using pulsed-wave Doppler ultrasound from 10 healthy age- and sex-matched controls and 36 patients with PAH. pPTT was reduced in patients with PAH compared with controls. Univariate analysis revealed the following significant predictors of reduced pPTT: age, right ventricular fractional area change (RV FAC), tricuspid annular plane excursion (TAPSE), pulmonary arterial pressures (PAP), diastolic pulmonary gradient, transpulmonary gradient, pulmonary vascular resistance, and RV-PA coupling (defined as RV FAC/mean PAP or TAPSE/mean PAP). Although the correlations between pPTT and invasive markers of pulmonary vascular disease were modest, RV FAC (r = 0.64, P < 0.0001), TAPSE (r = 0.67, P < 0.0001), and RV-PA coupling (RV FAC/mean PAP: r = 0.72, P < 0.0001; TAPSE/mean PAP: r = 0.74, P < 0.0001) had the strongest relationships with pPTT. On multivariable analysis, only RV FAC, TAPSE, and RV-PA coupling were independent predictors of pPTT. We conclude that shortening of pPTT in patients with PAH results from altered RV-PA coupling, probably occurring as a result of reduced pulmonary arterial compliance. Thus, pPTT allows noninvasive determination of the status of both the pulmonary vasculature and the response of the RV in patients with PAH, thereby allowing monitoring of disease progression and regression.

Right ventricular relative wall thickness as a predictor of outcomes and of right ventricular reverse remodeling for patients with pulmonary hypertension

Mid-term right ventricular (RV) reverse remodeling after treatment in patients with pulmonary hypertension (PH) is associated with long-term outcome as well as baseline RV remodeling. However, baseline factors influencing mid-term RV reverse remodeling after treatment and its prognostic capability remain unclear. We studied 54 PH patients. Mid-term RV remodeling was assessed in terms of the RV area, which was traced planimetrically at the end-systole (RVESA). RV reverse remodeling was defined as a relative decrease in the RVESA of at least 15% at 10.2 ± 9.4 months after treatment. Long-term follow-up was 5 years. Adverse events occurred in ten patients (19%) and mid-term RV reverse remodeling after treatment was observed in 37 (69%). Patients with mid-term RV reverse remodeling had more favorable long-term outcomes than those without (log-rank: p = 0.01). Multivariate logistic regression analysis showed that RV relative wall thickness (RV-RWT), as calculated as RV free-wall thickness/RV basal linear dimension at end-diastole, was an independent predictor of mid-term RV reverse remodeling (OR 1.334; 95% CI, 1.039-1.713; p = 0.03). Moreover, patients with RV-RWT ≥0.21 showed better long-term outcomes than did those without (log-rank p = 0.03), while those with RV-RWT ≥0.21 and mid-term RV reverse remodeling had the best long-term outcomes. Patients with RV-RWT <0.21 and without mid-term RV reverse remodeling, on the other hand, had worse long-term outcomes than other sub-groups. In conclusions, RV-RWT could predict mid-term RV reverse remodeling after treatment in PH patients, and was associated with long-term outcomes. Our finding may have clinical implications for better management of PH patients.

Right Ventricular Function Is Associated with Left Ventricular Stroke Volume in Patients with Severe Aortic Stenosis and Preserved Ejection Fraction

BACKGROUND

A subset of patients with severe aortic stenosis (AS) have lower stroke volumes and valve gradients despite a normal left ventricular ejection fraction (LVEF), referred to as paradoxical low-flow AS (PLF AS). However, the role of right ventricular (RV) function in patients with severe AS and preserved LVEF is not known. We hypothesized that right ventricular function is associated with left ventricular stroke volume in patients with severe AS and preserved LVEF.

METHODS

From an echocardiographic database, we retrospectively identified 102 patients with an indexed aortic valve area ≤0.6 cm(2) /m(2) and LVEF ≥ 50%. We used univariate and multivariate linear regression analysis to assess the association between aortic valve stroke volume index (SVi) and right ventricular systolic function as measured by tricuspid annular plane systolic excursion (TAPSE) and by right ventricular fractional area change (FAC).

RESULTS

Our population was 98% male with mean age 77.4 ± 9.3 years and mean SVi of 36.1 ± 7.9 mL/m(2) . Forty-four patients (43%) met criteria for PLF AS. TAPSE and FAC were positively associated with SVi in both univariate and multivariate regression analysis after correcting for left ventricular variables (β coefficient - TAPSE (cm): 4.59 ± 1.3, P = 0.001; FAC (%): 0.19 ± 0.08, P = 0.014). Additionally, PLF AS patients had significantly lower mean TAPSE and lower mean FAC when compared dichotomously to normal flow AS patients (P < 0.05).

CONCLUSIONS

Right ventricular systolic function assessed by TAPSE and FAC is significantly related to aortic valve flow in patients with severe AS and preserved LVEF.