Essential echocardiographic evaluation in patients with suspected pulmonary hypertension: an overview for the practicing physician

Prompt and accurate diagnosis of patients presenting with symptoms suggestive of pulmonary arterial hypertension (PAH) is of outmost importance as delays in identifying this clinical entity have detrimental effects on both morbidity and mortality. Initial noninvasive assessment of these patients has traditionally included a number of routine tests of which transthoracic echocardiography (TTE) has been shown to either confirm the presence of structural anomalies of the right ventricle (RV) indicative of PAH or exclude other potential causes of pulmonary hypertension (PH). Consequently, TTE has become a well-validated and readily available imaging tool not only used for this initial screening but also for routine follow-up of PH patients. Since chronic PH is known to unbalance the normal hemodynamic and mechanical homeostatic interaction between the RV and pulmonary circulation; the resulting response is that of an abnormal RV remodeling, clinically translated into progressive RV hypertrophy and dilatation. An enlarged and hypertrophied RV not only would eventually lose effective contractility but also this gradual decline in RV systolic function is the main abnormality in determining adverse clinical outcomes. Therefore, it is of outmost importance that TTE examination be comprehensive but most importantly accurate and reproducible. This review aims to highlight the most important objective measures that can be routinely employed, without added complexity, that will certainly enhance the interpretation and advance our understanding of the hemodynamic and mechanical abnormalities that PH exerts on the RV.

Assessing right ventricular function in patients with hypertrophic cardiomyopathy with cardiac MRI: correlation with the New York Heart Function Assessment (NYHA) classification

Purpose

To determine whether 3.0-T magnetic resonance imaging (MRI) could assess right ventricular (RV) function in patients with hypertrophic cardiomyopathy (HCM), and if this assessment is correlated with the New York Heart Function Assessment (NYHA) classification.

Materials and Methods

Forty-six patients with HCM and 23 normal individuals were recruited. Left and right ventricular function parameters including end-diastolic and end-systolic volumes (EDV, ESV), stroke volume (SV) and ejection fraction (EF) and dimensions were measured and compared using 3.0-T MRI. RV function parameters between HCM patients and controls were compared using independent sample t tests. A one way ANOVA test with Bonferroni correction was used to determine significant differences among different NYHA groups. Receiver operating characteristic analyses calculated the sensitivity and specificity of RV dysfunction on MRI for the prediction of HCM severity.

Results

Statistical analysis revealed significant differences of left ventricular (LV) and RV volumetric values and masses between the HCM patients and controls (all p<0.05). Within the HCM group, the simultaneously decreased maximum RVEDD correlated well with the LVEDD (r = 0.53; p<0.001). The function and dimension parameters among Class I to III were not determined to be significantly different (all p>0.05). However, significant differences between the Class IV and I-III groups (all P<0.0167) indicated that the diastolic and systolic function in both the RV and LV were impaired in Class IV patients. ROC analyses identified the EDV, ESV and EDD of both the LV and RV with a high sensitivity cutoff value to predict the HCM patients with severe heart failure (Class IV) with high sensitivity and specificity.

Conclusions

RV involvements were comparable to those of LV global function impairments in patients with HCM. The presence of RV dysfunction and decreased dimension on the MRI helped to predict the severe symptomatic HCM with high sensitivity and specificity.

Echocardiographic assessment of right ventricular function in inferior wall myocardial infarction and angiographic correlation to proximal right coronary artery stenosis

BACKGROUND

Presence of right ventricular (RV) infarction imposes a higher risk of adverse events in inferior wall myocardial infarction (IWMI). In this study, we attempted to correlate various indices of RV function assessed by echocardiography with presence of a proximal right coronary artery (RCA) stenosis in patients with first episode of acute IWMI.

METHODS

In a prospective study, patients with first episode of acute IWMI underwent echocardiographic assessment within 24 h of symptom onset and indices of RV function viz. RV fractional area change (RVFAC), tricuspid annular plane systolic excursion (TAPSE), myocardial performance index (MPI) and tissue Doppler velocities from RV free wall were measured. Patients who underwent coronary angiogram (CAG) within one month and they were classified into group 1 and group 2 based on the presence or absence, respectively, of a significant proximal RCA stenosis.

RESULTS

There were 90 patients with first episode of IWMI of which 67 patients underwent CAG. There was significant difference between group 1 (n = 26) and group 2 (n = 41) in TAPSE (13.5 ± 1.3 vs 21.3 ± 1.7, p < 0.001), MPI by tissue Doppler (0.87 ± 0.1 vs 0.55 ± 0.2, p < 0.001) and in tissue Doppler systolic velocity from RV free wall (S' 9.8 ± 1.1 vs 15.0 ± 1.5, p < 0.001). There was a good interobserver correlation for TAPSE, MPI by TDI, and S' velocity. TAPSE ≤ 16 (sensitivity 93%, specificity 100%), MPI-TDI ≥ 0.69 (sensitivity 94.7%, specificity 93.5%), S ≤ 12.3 (sensitivity 90.3%, specificity 94.3%) were useful in predicting presence of proximal RCA stenosis.

CONCLUSION

RV function indices like TAPSE, MPI-TDI and S' velocity are useful in predicting proximal RCA stenosis in first episode of acute IWMI.

ECHOCARDIOGRAPHY IN RIGHT VENTRICULAR MYOCARDIAL INFARCTION

This paper presents the views on two-dimensional (2D) echocardiography (EchoCG) in the assessment of right ventricular (RV) structure and function. In order to quantitatively assess the RV global function, the following parameters can be used: RV outflow tract shortening fraction, RV fractional area change, tricuspid annular plane systolic excursion, and Tei index. For these parameters, their assessment methods, as well as their strengths and limitations, are discussed.

Assessment of ventricular functions by tissue Doppler echocardiography in children with asthma

Patients with asthma develop pulmonary hypertension due to recurrent hypoxia and chronic inflammation, leading to right heart enlargement with ventricular hypertrophy. Patients with severe asthma can experience cor pulmonale later in life, but little is known about ventricular function during the early stages of the disease. This study aimed to investigate ventricular functions in asymptomatic children with asthma as detected by conventional echocardiography and tissue Doppler echocardiography (TDE). Fifty-one pediatric patients (mean age 10.4 ± 2.2 years) with asthma and 46 age- and sex-matched healthy children (mean age 10.9 ± 2.4 years) were studied. All subjects were examined by conventional echocardiography and TDE, and they had pulmonary function tests on spirometry. The right-ventricular (RV) wall was statistically (p = 0.01) thicker among asthmatic patients (4.7 ± 1.5 mm) compared with healthy children (3.6 ± 0.4 mm). However, conventional pulsed-Doppler indices of both ventricles did not differ significantly between asthmatic patients and healthy children (p > 0.05). The results of TDE examining RV diastolic function showed that annular peak velocity during early diastole (E'), annular peak velocity during late diastole (A') (16.4 ± 1.8 and 5.1 ± 1.4 cm/s, respectively), E'/A' ratio (3.2 ± 0.7), isovolumetric relaxation time (67.7 ± 10.2 ms) and myocardial performance index (48.1 % ± 7.0 %) of the lateral tricuspid annulus among asthmatic patients differed significantly (p = 0.01) from those of healthy children (13.2 ± 2.3, 8.2 ± 2.0 cm/s, 1.6 ± 0.5, 46.2 ± 8.7 ms, and 42.0 % ± 5.7 %, respectively). Only peak expiratory flow (PEF) rate from the pulmonary function tests was negatively correlated with the E'/A' ratio of the tricuspid annulus (r = -0.38, p = 0.01). This study showed that although the findings of clinical and conventional echocardiography were apparently normal in children with asthma, TDE showed subclinical dysfunction of the right ventricle, which is negatively correlated with PEF. These findings signify the diagnostic value of TDE in the early detection and monitoring of such deleterious effects among asthmatic patients.

Total Ischemia Time Alters the Longitudinal and Circumferential Shortening of the Right Ventricle in Transplanted Hearts

Objectives. Ischemia time is a risk factor for mortality and right ventricular (RV) failure after heart transplantation. The purpose of this study was to determine the effect of ischemia time on known transesophageal echocardiography (TEE) parameters of RV function and on a novel quantitative measurement of RV circumferential shortening. Methods. Right and left ventricular (LV) function was evaluated retrospectively in 20 consecutive patients after heart transplant using known TEE parameters as well as a quantitative measurement of circumferential contraction. The control group consisted of 20 patients undergoing coronary artery bypass grafting (CABG) with no documented RV dysfunction. Results. Posttransplant TEE parameters of RV function were depressed compared with post–cardiopulmonary bypass CABG patients. Significant correlation was observed between tricuspid annular planar systolic excursion, basal, mid, and global circumferential shortening and total ischemia time. Conclusion. Total ischemia time of the transplanted heart may play a role in deterioration of longitudinal and circumferential shortening of the RV.

Assessment of correlation between CT angiographic clot load score, pulmonary perfusion defect score and global right ventricular function with dual-source CT for acute pulmonary embolism

OBJECTIVE

The purpose of this study was to prospectively investigate the correlation between CT angiographic clot load (CTACL) score, pulmonary perfusion defect (PPD) score and the global right ventricular function in the assessment of pulmonary embolism (PE) severity.

METHODS

49 patients with acute PE, who underwent dual-source CT scan, were included in the study. CT angiography and perfusion imaging were performed. Data from electrocardiogram-gated coronary angiography scanning protocol were used for right ventricular function analysis. Two readers evaluated the CTACL and PPD scores using the Qanadli and Chae methods, respectively.

RESULTS

The PPD score had a strong positive correlation with the CTACL score (r=0.72, p<0.001) and both scores in turn had a strong positive correlation with the right ventricular/left ventricular (RV/LV) diameter ratio (r=0.60, r=0.62, p<0.001). However, the PPD score had a strong negative correlation with ejection fraction (EF) (r=-0.63, p<0.001) while the CTACL score had a low negative correlation with EF (r=-0.33, p=0.02). Between the RV/LV<1 group (n=35) and the RV/LV >1 group (n=14), the PPD score, CTACL score, pulmonary artery trunk diameter, EF and reflux of inferior vena cava were significantly different, all with p<0.001. The end-systolic volume (p=0.01) was significantly different but the end-diastolic volume (p=0.11) and stroke volume (p=0.08) showed no statistically significant difference between the two groups.

CONCLUSION

Therefore, considering PPD scores, CTACL scores and cardiovascular manifestations together may be helpful in the evaluation of PE severity.

Right ventricular function in children with bronchial asthma: a tissue Doppler echocardiographic study

Asthma is the most common cause of respiratory disability among children. Patients with severe bronchial asthma can experience cor pulmonale later in life, but little is known about the function of the right ventricle early in the disease. This study aimed to investigate the right ventricular function in children with bronchial asthma as detected by tissue Doppler echocardiography. This case-control study compared 60 asthmatic children ages 5 to 15 years between attacks (study group) with 60 apparently healthy children (control group). All the children were subjected to full history-taking, complete physical examination, measurement of peak expiratory flow rate (PEFR), chest x-ray, electrocardiography (ECG), echocardiographic examination, and both conventional and tissue Doppler study. The results of the tissue Doppler study examining the right ventricular diastolic function showed that peak E' velocity (10.08 ± 2.8 cm/s), peak A' velocity (5.7 ± 2.5 cm/s), E'/A' ratio (1.77 ± 0.58 m/s), and isovolumetric relaxation time (IVRT) of the lateral tricuspid annulus (138.9 ± 30.7 m/s) among the asthmatic patients differed significantly from those among the control subjects (12.4 ± 2.3, 7.8 ± 2.1 cm/s; 1.58 ± 0.32, and 91.1 ± 32.6 m/s, respectively). In addition, the E' velocity and IVRT of the lateral tricuspid annulus were significantly different among the mild, moderate, and severe cases (P < 0.001). It is concluded that although the clinical and conventional echocardiographic findings of the asthmatic children were apparently normal, the tissue Doppler echocardiographic study showed right ventricular dysfunction that is positively correlated with the severity of asthma. These findings signify the diagnostic value of tissue Doppler echocardiography for the early detection and monitoring of such deleterious effects among asthmatic patients.

Right ventricular ejection fraction is better reflected by transverse rather than longitudinal wall motion in pulmonary hypertension

BACKGROUND

Longitudinal wall motion of the right ventricle (RV), generally quantified as tricuspid annular systolic excursion (TAPSE), has been well studied in pulmonary hypertension (PH). In contrast, transverse wall motion has been examined less. Therefore, the aim of this study was to evaluate regional RV transverse wall motion in PH, and its relation to global RV pump function, quantified as RV ejection fraction (RVEF).

METHODS

In 101 PH patients and 29 control subjects cardiovascular magnetic resonance was performed. From four-chamber cine imaging, RV transverse motion was quantified as the change of the septum-free-wall (SF) distance between end-diastole and end-systole at seven levels along an apex-to-base axis. For each level, regional absolute and fractional transverse distance change (SFD and fractional-SFD) were computed and related to RVEF. Longitudinal measures, including TAPSE and fractional tricuspid-annulus-apex distance change (fractional-TAAD) were evaluated for comparison.

RESULTS

Transverse wall motion was significantly reduced at all levels compared to control subjects (p < 0.001). For all levels, fractional-SFD and SFD were related to RVEF, with the strongest relation at mid RV (R(2) = 0.70, p < 0.001 and R(2) = 0.62, p < 0.001). For TAPSE and fractional-TAAD, weaker relations with RVEF were found (R(2) = 0.21, p < 0.001 and R(2) = 0.27, p < 0.001).

CONCLUSIONS

Regional transverse wall movements provide important information of RV function in PH. Compared to longitudinal motion, transverse motion at mid RV reveals a significantly stronger relationship with RVEF and thereby might be a better predictor for RV function.

The echocardiographic assessment of the right ventricle: what to do in 2010?

For many years, the echocardiographic quantitative assessment of right ventricular (RV) function has been difficult owing to the complex RV anatomy. Identifying an accurate and reliable echocardiographic parameter for the functional assessment of the RV still remains a challenge. The review presents a summary of the most studied and presently used parameters of RV function, with their reported normal values, as well as advantages and limitations of use. Combinations of these parameters are used in daily clinical practice, each one offering only partial information about the status of the RV. Myocardial velocity and strain rate imaging have promising results in the assessment of RV function. There is hope that novel myocardial deformation parameters and three-dimensional echocardiography-derived parameters may add value to the examination of the RV, but validation studies are still needed.