Right and left heart dysfunction predict mortality in pulmonary hypertension

Prognostic value of right ventricular free-wall longitudinal strain in patients with pulmonary hypertension: systematic review and meta-analyses

BACKGROUND

Right ventricular (RV) dysfunction is associated with adverse outcomes in patients with pulmonary hypertension (PH). This systematic review and meta-analysis evaluated the prognostic value of RV free-wall longitudinal strain (RVfwLS), compared with other RV parameters in PH.

METHODS

We searched for articles presenting the HR of two-dimensional RVfwLS in PH. HRs were standardised using the within-study SD. The ratio of HRs of a 1 SD change in RVfwLS versus systolic pulmonary arterial pressure (SPAP), systolic tricuspid annular velocities (s'-TV), RV fractional area change (FAC) or tricuspid annular plane systolic excursion (TAPSE) was calculated for each study, after which we conducted a random model meta-analysis. Subgroup analysis regarding the type of outcome, aetiology of PH and software vendor was also performed.

RESULTS

Twenty articles totalling 2790 subjects were included. The pooled HR of a 1 SD decrease of RVfwLS was 1.80 (95% CI: 1.62 to 2.00, p<0.001), and there was a significant association with all-cause death (ACD) and composite endpoints (CEs). The ratio of HR analysis revealed that RVfwLS has a significant, strong association with ACD and CE per 1 SD change, compared with corresponding values of SPAP, s'-TV, RVFAC or TAPSE. RVfwLS was a significant prognostic factor regardless of the aetiology of PH. However, significant superiority of RVfwLS versus other parameters was not observed in group 1 PH.

CONCLUSIONS

The prognostic value of RVfwLS in patients with PH was confirmed, and RVfwLS is better than other RV parameters and SPAP. Further accumulation of evidence is needed to perform a detailed subgroup analysis for each type of PH.

TRIAL REGISTRATION NUMBER

UMIN Clinical Trials Registry (UMIN000052679).

Right ventricular systolic strain in patients with pulmonary hypertension: clinical feasibility, reproducibility, and correlation with ejection fraction

BACKGROUND

Right ventricular (RV) systolic function is the major determinant of prognosis in patients with pulmonary hypertension (PH) with quantitative assessment by speckle-tracking strain echocardiography emerging as a viable candidate measure.

METHOD

We evaluated a prospective cohort of 231 patients with known or suspected PH referred for clinical echocardiography. All underwent measurement of RV free-wall systolic strain by sonographer staff. Digital images were recorded for blinded offline assessment by an expert echocardiographer. Reproducibility was assessed using the analysis methods of Bland-Altman and the Cohen's-Kappa coefficient.

RESULTS

RV strain was feasible in 213 (92%). The average RV systolic pressure was 59 ± 22 mmHg. RV systolic strain correlated with functional class, NT-proBNP, and the degree of RV enlargement. The average free-wall systolic strain was - 20 ± 7% (range  - 2 to  - 37%). The RV strain measures (clinical practice versus blinded expert) had an excellent correlation with a normal distribution (R2 0.87, p < 0.0001). By Bland-Altman analysis, the mean difference in measurement was - 1.7% (95% CI - 1.4 to - 2.1) with a correlation of 0.93, p value of < 0.0001. The reproducibility of RV strain for clinically relevant thresholds was also excellent (Kappa coefficients 0.68-0.83). There was no effect on the variability of strain measures across body mass, pulmonary pressures, or rhythm. RV strain correlated with RV diastolic volumes and ejection fraction with RV free wall strain being the best echo predictor for a reduction in ejection fraction.

CONCLUSION

Here RV systolic strain was found to be highly feasible and reproducible in clinical practice with excellent levels of agreement for clinically relevant thresholds.

Underfilling decreases left ventricular function in pulmonary arterial hypertension

To evaluate the association between impaired left ventricular (LV) longitudinal function and LV underfilling in patients with pulmonary arterial hypertension (PAH). Thirty-nine patients with PAH and 18 age and sex-matched healthy controls were included. LV volume and left atrial volume (LAV) were delineated in short-axis cardiac magnetic resonance (CMR) cine images. LV longitudinal function was assessed from atrio-ventricular plane displacement (AVPD) and global longitudinal strain (GLS) was assessed using feature tracking in three long-axis views. LV filling was assessed by LAV and by pulmonary artery wedge pressure (PAWP) using right heart catheterisation. Patients had a smaller LAV, LV volume and stroke volume as well as a lower LV-AVPD and LV-GLS than controls. PAWP was 6 [IQR 5––9] mmHg in patients. LV ejection fraction did not differ between groups. LV stroke volume correlated with LV-AVPD (r = 0.445, p = .001), LV-GLS (r = − 0.549, p < 0.0001) and LAVmax (r = .585, p < 0.0001). Furthermore, LV-AVPD (r = .598) and LV-GLS (r = − 0.675) correlated with LAVmax (p < 0.0001 for both). Neither LV-AVPD, LV-GLS, LAVmax nor stroke volume correlated with PAWP. Impaired LV longitudinal function was associated with low stroke volume, low PAWP and a small LAV in PAH. Small stroke volumes and LAV, together with normal LA pressure, implies that the mechanism causing reduced LV longitudinal function is underfilling rather than an intrinsic LV dysfunction in PAH.

BMI Is Causally Associated With Pulmonary Artery Pressure But Not Hemodynamic Evidence of Pulmonary Vascular Remodeling

BACKGROUND

There is an unclear relationship of obesity to the pathogenesis and severity of pulmonary arterial hypertension (PAH) and pulmonary venous hypertension (PVH).

RESEARCH QUESTION

Is BMI casually associated with pulmonary artery pressure (PAP) and/or markers of pulmonary vascular remodeling?

STUDY DESIGN AND METHODS

The study design was a two-sample inverse-variance weighted Mendelian randomization. We constructed two BMI genetic risk scores from genome-wide association study summary data and deployed them in nonoverlapping cohorts of subjects referred for right heart catheterization (RHC) or echocardiography. A BMI highly polygenic risk score (hpGRS) optimally powered to detect shared genetic architecture of obesity with other traits was tested for association with RHC parameters including markers of pulmonary vascular remodeling. A BMI strict genetic risk score (sGRS) composed of high-confidence genetic variants was used for Mendelian randomization analyses to assess if higher BMI causes higher PAP.

RESULTS

Among all subjects, both directly measured BMI and hpGRS were positively associated with pulmonary arterial pressures but not markers of pulmonary vascular remodeling. Categorical analyses revealed BMI and hpGRS were associated with PVH but not PAH. Mendelian randomization of the sGRS supported that higher BMI is causal of higher systolic pulmonary artery pressure (sPAP). Sensitivity analyses showed sPAP-BMI sGRS relationship was preserved when either individuals with PAH or PVH were excluded. In the echocardiographic cohort, BMI and hpGRS were positively associated with estimated PAP and markers of left heart remodeling.

INTERPRETATION

BMI is a modifier of pulmonary hypertension severity in both PAH and PVH but is only involved in the pathogenesis of PVH.

Diastolic function assessment by echocardiography: A practical manual for clinical use and future applications

Diastole is an important component of the cardiac cycle, during which time optimum filling of the ventricle determines physiological stroke volume ejected in the succeeding systole. Many factors contribute to optimum ventricular filling including venous return, left atrial filling from the pulmonary circulation, and emptying into the left ventricle. Left ventricular filling is also impacted by the cavity emptying function and also its synchronous function which may suppress early diastolic filling in severe cases of dyssynchrony. Sub-optimum LA emptying increases cavity pressure, causes enlarged left atrium, unstable myocardial function, and hence atrial arrhythmia, even atrial fibrillation. Patients with clear signs of raised left atrial pressure are usually symptomatic with exertional breathlessness. Doppler echocardiography is an ideal noninvasive investigation for diagnosing raised left atrial pressure as well as following treatment for heart failure. Spectral Doppler based increased E/A, shortened E-wave deceleration time, increased E/e', and prolonged atrial flow reversal in the pulmonary veins are all signs of raised left atrial pressure. Left atrial reduced myocardial strain is another correlate of raised cavity pressure (>15 mm Hg). In patients with inconclusive signs of raised left atrial pressure at rest, exercise/stress echocardiography or simply passive leg lifting should identify those with stiff left ventricular which suffers raised filling pressures with increased venous return.

Two-dimensional speckle tracking echocardiography detected interventricular dyssynchrony predicts exercise capacity and disease severity in pre-capillary pulmonary hypertension

Background

Right ventricular (RV) intraventricular mechanical dyssynchrony detected by two-dimensional speckle tracking echocardiography (2D-STE) has been reported to be correlated with a decrease in RV contractile efficiency in pulmonary hypertension (PH) patients, while little attention has been paid to biventricular dysfunction. Therefore, we aimed to evaluate the predictive value of 2D-STE detected interventricular dyssynchrony for exercise capacity and disease severity in patients with pre-capillary PH (PcPH).

Methods

Conventional transthoracic echocardiography, 2D-STE and cardiopulmonary exercise tests (CPETs) were performed in all participants. Intra- and interventricular dyssynchrony were calculated as the standard deviation (SD) of the time intervals corrected for heart rate between QRS onset and peak longitudinal strain. Multivariate linear regression analyses were performed to identify independent predictors of peak oxygen consumption (PVO₂) during the CPET. Multivariable logistical regression modeling was used to analyze the associations between interventricular dyssynchrony and risk assessment.

Results

Sixty-six PcPH patients were consecutively recruited (19 male and 47 female, average 35 years old). WHO functional class, N-terminal pro-brain natriuretic peptide (BNP) and body mass index were included as independent predictors in the first multivariate regression analysis of clinical data without echocardiographic parameters (Model-1, r²=0.423, P<0.001). We subsequently added conventional echocardiographic parameters and 2D-STE parameters to the clinical data, RV fractional area change (Model-2, r²=0.417, P<0.001), RV global longitudinal strain (Model-3, r²=0.454, P=0.001), RV intraventricular dyssynchrony (Model-4: r²=0.474, P<0.001) and interventricular dyssynchrony (Model-5, r²=0.483, P<0.001) were identified as independent predictors of PVO₂. Interventricular dyssynchrony, calculated as the SD of the time intervals of nine segments, was independently associated with risk assessment (odd ratio 1.027, 95% CI: 1.003–1.052, P=0.03). The area under the receiver-operating characteristic curve (AUC) was 0.73 (P<0.001).

Conclusions

Interventricular dyssynchrony detected by 2D-STE contributed to a better evaluation of exercise capacity and disease severity in PcPH patients.

The prognostic role of speckle tracking echocardiography in clinical practice: evidence and reference values from the literature

Speckle tracking echocardiography (STE) is a second-level echocardiographic technique which has gradually gained relevance in the last years. It allows semi-automatic quantification of myocardial deformation and function, overcoming most of the limitations characterizing basic echocardiography and providing an early detection of cardiac impairment. Today, its feasibility and usefulness are highly supported by literature. In particular, several studies demonstrated that STE could provide additional prognostic information beyond conventional echocardiographic and traditional clinical parameters. Moreover, a recent standardization of speckle tracking analysis regarding all cardiac chambers paved the way for the integration of STE in diagnostic and prognostic protocols for particular clinical settings. The aim of this review is to describe the prognostic role of STE in different clinical scenarios basing on currently available evidence.

Decreased biventricular longitudinal strain in patients with systemic sclerosis is mainly caused by pulmonary hypertension and not by systemic sclerosis per se

Purpose

Patients with pulmonary arterial hypertension (PAH) due to systemic sclerosis (SSc) have high mortality. Left ventricular (LV) peak global longitudinal strain (GLS) is decreased in SSc. It is unknown whether low GLS is due to SSc or PAH. Therefore, our primary aim was to evaluate both LV and right ventricular free wall GLS (RVFW GLS) in SSc, with and without PAH, using cardiac magnetic resonance with feature tracking. Secondary aim was to relate GLS to invasive mean pulmonary arterial pressure (mPAP) and pulmonary vascular resistance (PVR).

Methods

Thirty‐eight patients with SSc, 19 patients with SSc‐PAH and 19 healthy controls for comparison, were included. Endocardial and epicardial borders were delineated in cine images (short‐axis stack and three long‐axis views) for volumetric and strain calculations.

Results

Systemic sclerosis‐PAH had lower LV and RVFW GLS than SSc (LV: P = 0·01, RV: P<0·001) and controls (LV: P = 0·02; RV: P<0·001), with no difference between SSc and controls. LV strain correlated with mPAP (R = 0·42, P = 0·03) and PVR (R = 0·52, P = 0·006). RVFW GLS correlated with mPAP (R = 0·68, P<0·001) and PVR (R = 0·59, P = 0·001). ROC curves for predicting PAH had AUC 0·73 for LV strain (P = 0·003) and 0·86 for RVFW GLS (P<0·001).

Conclusions

Lower GLS is mainly determined by increased pulmonary pressure and not by SSc per se. Low LV and RVFW GLS are indicative of increased mPAP and PVR, which opens for improved non‐invasive methods to select patients eligible for right heart catheterization and to monitor the effects of PAH therapy.

The Syndrome of Inter-atrial Conduction Block

The formulation of the syndrome of interatrial conduction block is an important step for improved identification of patients at high risk of developing atrial fibrillation (those with advanced, that is, third degree interatrial block, which includes retrograde instead of normal activation of the left atrium). The rationale and potential benefits of prophylactic antiarrhythmic treatment of patients with advanced interatrial block currently seems not sufficiently convincing and requires further study including prospective trials. In addition to the identified future directions for research in this syndrome, it seems important also to explore novel electrocardiogram (ECG) methods (e.g. new electrode positions and ECG leads) for improved characterisation of the atrial electrical events. Oesophageal electrocardiography and vectorcardiography are old, venerable and unjustifiably forgotten ECG techniques: their additional use of for better diagnosis of interatrial conduction block is highly commendable.

Multimodality Evaluation of the Right Ventricle: An Updated Review

The assessment of the volumes, function, and mechanics of the right ventricle (RV) is very challenging because of the anatomical complexity of the RV. Because RV structure, function, and deformation are very important predictors of cardiovascular morbidity and mortality in patients with heart failure, pulmonary hypertension, congenital heart disease, or arrhythmogenic RV cardiomyopathy, it is of great importance to use an appropriate imaging modality that will provide all necessary information. In everyday clinical practice, 2-dimensional echocardiography (2DE) represents a method of first choice in RV evaluation. However, cardiac magnetic resonance (CMR) remained the gold standard for RV assessment. The development of new imaging tools, such as 3-dimensional echocardiography (3DE), provided reliable data, comparable with CMR, and opened a completely new era in RV imaging. So far, 3DE has shown good results in determination of RV volumes and systolic function, and there are indications that it will also provide valuable data about 3-dimensional RV mechanics, similar to CMR. Two-dimensional echocardiography-derived strain is currently widely used for the assessment of RV deformation, which has been proven to be a more significant predictor of functional capacity and survival than CMR-derived RV ejection fraction. The purpose of this review is to summarize currently available data about RV structure, function, and mechanics obtained by different imaging modalities, primarily 2DE and 3DE, and their comparison with CMR and cardiac computed tomography.

Assessment of Left Ventricular Diastolic Function by Doppler Echocardiography

Diastole is an essential part of the cardiac cycle, during which significant changes in myocardial function, ion and energy transfer, as well as coronary flow, occur. In contrast to systole, diastole consists of four phases, each of which has its distinguishing function and events. However, the four phases are inter-related with events in early diastole correlating with those in late diastole and those occurring during the isovolumic relaxation time predicting both. The complexity of diastolic phases is reflected in the ways by which diastolic function is assessed. While intra-cardiac flow velocities, into and out of the atria, are measured by pulsed-wave Doppler, those of wall motion are assessed by M-mode, myocardial Doppler velocities or, recently, speckle tracking technique. Optimum integration of various aspects of diastolic function should always be considered in order to obtain an accurate comprehensive assessment, bearing in mind factors that normally affect it, for example age.