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ORIGINAL ARTICLE
Year : 2014  |  Volume : 27  |  Issue : 2  |  Page : 336-341

Echocardiographic assessment of right ventricular function in patients with pulmonary hypertension: Strain imaging study


Department of Cardiology, Faculty of Medicine, Menoufia University, Menoufia, Egypt

Date of Submission09-Jun-2013
Date of Acceptance25-Aug-2013
Date of Web Publication26-Sep-2014

Correspondence Address:
Essam Mohamed Saleh Ragab
MBBCh, Elminshat Elkobra, Elsanta-Gharbia
Egypt
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/1110-2098.141700

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  Abstract 

Objective
The aim of the study was to assess the right ventricular (RV) function in patients with pulmonary hypertension (PH) using strain imaging.
Background
Noninvasive techniques evaluating RV performance have important limitations, and strain imaging studies have helped overcome some of these limitations.
Patients and methods
Fifty patients with PH (72% male and 28% female; mean age 55.76 ± 14.60 years) and 20 age-matched and sex-matched controls were studied using Vivid 9. Apical four-chamber view was used to measure the strain and strain rate of the RV free wall and septal wall. Parameters were quantified in basal, mid, and apical segments of the septal and RV free wall and measures were correlated with pulmonary artery systolic pressure.
Results
There was a statistically significant difference between patients and controls with regard to strain of the RV free wall (P < 0.001) and strain rate of the RV free wall (P < 0.001). There was significant negative correlation between pulmonary artery systolic pressure and strain of the RV free wall (r = −0.459, P < 0.001) and strain rate of the RV free wall (r = −0.526, P < 0.001).
Conclusion
The impairment of RV myocardial deformation is evident in patients with PH using strain and strain rate.

Keywords: Pulmonary hypertension, right ventricular function, strain and strain rate


How to cite this article:
Elnoamany MF, Ahmed NF, Ragab EM. Echocardiographic assessment of right ventricular function in patients with pulmonary hypertension: Strain imaging study. Menoufia Med J 2014;27:336-41

How to cite this URL:
Elnoamany MF, Ahmed NF, Ragab EM. Echocardiographic assessment of right ventricular function in patients with pulmonary hypertension: Strain imaging study. Menoufia Med J [serial online] 2014 [cited 2020 Feb 17];27:336-41. Available from: http://www.mmj.eg.net/text.asp?2014/27/2/336/141700


  Introduction Top


Pulmonary hypertension (PH) commonly refers to elevation of the pulmonary artery pressure above normal, and is defined as a pulmonary artery systolic pressure (PASP) greater than 35 mmHg or a mean pulmonary artery pressure greater than 25 mmHg at rest. PH is present in a number of conditions - for example, chronic obstructive pulmonary disease and pulmonary embolism. It may also reflect the presence of underlying pulmonary vascular disease, which can be progressive and fatal, or the presence of elevated pressure in the left heart [1].

Right ventricular (RV) systolic dysfunction has been identified as a key element in determining the prognosis of patients afflicted with chronic PH [2].

Therefore, identification of early RV dysfunction is of outmost clinical importance as nearly two-thirds of deaths in patients with chronic PH may be attributed to RV failure [3].

All invasive and noninvasive techniques evaluating RV performance have important limitations due to the complex geometry of the RV [4].

The recent introduction of strain and strain rate echocardiography using tissue Doppler imaging (TDI) has provided an objective means for quantifying global and regional left ventricular function with improved accuracy and greater reproducibility compared with conventional echocardiography [5].

We have recently reported that TDI is also useful in identifying RV free wall mechanical delay in patients with chronic PH [6].

Strain rate imaging allows the determination of velocity gradients between two points in space. The resulting contraction variable is independent of passive tethering effects from other regions and therefore appears promising for quantification of regional myocardial function [7],[8].


  Patients and methods Top


This study was performed on 70 patients (50 male and 20 female) at the Cardiology and Chest Departments and the Outpatient Clinic of Menoufia University Hospital between August 2012 and May 2013; these patients were subjected to an echocardiograghic examination.

The patients were classified into two groups according to their PASP and compared with each other with respect to Doppler echocardiographic data.

(1) Group I: this group included 20 patients having PASP less than 40 mmHg, who served as the control group.

(2) Group II: this group included 50 patients having PASP more than 40 mmHg.

Inclusion criteria

Patients with a sinus rhythm were included in the study.

Exclusion criteria

  1. Presence of a rhythm other than sinus rhythm.
  2. Presence of a pacemaker or defibrillator lead in the RV.
  3. Complete right or left bundle branch block in order to avoid alterations in timings of the cardiac cycle due to conduction disturbances.
  4. Pericardial diseases.
  5. Pulmonary stenosis of different etiologies.


Every patient was subjected to the following:

  1. Full history taking.
  2. Complete physical examination.
  3. Resting 12-lead ECG.
  4. Standard echocardiography:

    1. Two-dimensional echocardiography.
    2. M-mode echocardiography.
    3. Doppler echocardiography.


  5. Tissue Doppler.
  6. Two-dimensional strain imaging study.


Echocardiography

Echocardiography was performed with a standard ultrasound machine (Vivid 9; General Electric Medical Systems, Horten, Norway) equipped with 5 MHz variable-frequency harmonic-phased array transducers with a simultaneous ECG signaling. All participants were studied in the left lateral recumbent position [9].

Images were recorded in the standard parasternal long-axis and short-axis and apical four-chamber, two-chamber, and five-chamber views.

Routine M-mode, two-dimensional, pulsed, and continuous wave Doppler recordings were obtained for each participant for:

(1) Estimation of aortic and left atrial diameter.

(2) Estimation of left ventricular function (EF%).

(3) Estimation of left ventricular dimension (EDD and ESD).

(4) Estimation of tricuspid regurge and assessment of severity.

Color Doppler mapping was used at the tricuspid valve for assessment of TR and its severity, and right ventricular systolic pressure (RVSP) was calculated using Bernolli's equation [10]:

RVSP = 4 (velocity) 2 + RApressure.

(5) Estimation of RV area and fractional area change (FAC), defined as: (end diastolic area−end systolic area)/end diastolic area × 100 [11].

(6) Tricuspid annular plane systolic excursion (TAPSE).

(7) Mitral annular plane systolic excursion.

Tissue Doppler

The most reliably and reproducibly imaged regions of the RV are the tricuspid annuls. To perform this measure, an apical four-chamber window was used with a tissue Doppler mode region of interest highlighting the RV free wall. The pulsed Doppler sample volume was placed in the tricuspid annulus at the basal segment of the RV free wall. SͲ velocity had been shown to correlate well with other measures of global RV systolic function. SͲ velocity lower than 10 cm/s indicated RV systolic dysfunction [12].

Strain and strain rate imaging study

Separate color TVI images were saved with a color frame rate of 100-140 frames/s in the apical four-chamber view.

These color TVI images were recorded with digital media using high spatial resolution. Three cardiac cycles were saved in digital format.

Offline analysis of saved images was carried out. The myocardial strain and strain rate were measured applying the software incorporated in the Vivid 9 (General Electric Medical Systems):

  1. Assessing the RV free wall from the base to the apical level for three segments (basal-mid-apical) [13].
  2. Assessing the IVS from the base to the apical level for three segments (basal-mid-apical).


Statistical analyses

Data were statistically described in terms of range, mean, SD, frequencies (number of cases), and relative frequencies (%) when appropriate. Comparison of quantitative variables between the study groups was made using the T-test for paired samples. A P-value less than 0.05 was considered statistically significant. All statistical calculations were performed using statistical package for the social sciences (SPSS, version 12; SPSS Inc., Chicago, Illinois, USA) computer package, a statistical program for Microsoft Windows.


  Result Top


This study included 70 patients (50 male and 20 female) selected for echocardiographic examination at the Cardiology Department of Menoufia University Hospital and were classified according their PASP into two groups:

  1. Group I: this group comprised 14 male and six female participants, constituting the control group, with PASP less than 40 mmHg (n = 20).
  2. Group II: this group comprised 36 male and 14 female patients with PASP greater than 40 mmHg (n = 50).


RV data of the studied groups [Table 1] and [Figure 1] revealed a statistically highly significant difference among the studied groups:

  1. PASP of patients was 54.94 ± 16.15 but 23.75 ± 6.03 mmHg for controls (P < 0.001).
  2. TAPSE of patients was 13.52 ± 1.96 but 19.90 ± 2.43 mm for controls (P < 0.001).
  3. SͲ of patients was 8.32 ± 1.25 but 12.45 ± 2.33 cm/s in controls (P < 0.001).
  4. EͲ of patients was 8.56 ± 3.14 but 12.60 ± 4.79 cm/s in controls (P < 0.001).
  5. Right ventricular isovolumic relaxation time (rIVRT) in patients was 112.34 ± 25 but 43.40 ± 13.20 ms in controls (P < 0.001).
  6. FAC% in patients was 29.05 ± 5.69 but 39.55 ± 4.33% in controls (P < 0.001).
Figure 1:

Click here to view
Table 1: Right ventricle data of the studied groups

Click here to view


Strain of the RV free wall [Table 2] and [Figure 2] showed statistically highly significant difference among the studied groups:

  1. Basal strain in patients was −13.13 ± 4.13 but −22.67 ± 1.13 in the control group (P < 0.001).
  2. Mid strain in patients was −12.66 ± 5.07 but −22.18 ± 1.54 in the control group (P < 0.001).
  3. Apical strain in patients was −12.26 ± 5.01 but −21.26 ± 1.08 in the control group (P < 0.001).
Figure 2:

Click here to view
Table 2: Strain of right ventricle free wall of the studied groups

Click here to view


The strain rate of the RV free wall [Table 3] and [Figure 3] showed a statistically highly significant difference among the studied groups:

  1. Basal strain rate for patients was −0.81 ± 0.30 but −1.31 ± 0.14 in the control group (P < 0.001).
  2. Mid strain rate for patients was −0.78 ± 0.35 but −1.26 ± 0.13 in the control group (P < 0.001).
  3. Apical strain rate for patients was −0.72 ± 0.38 but −1.17 ± 0.09 in the control group (P < 0.001).
Figure 3:

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Table 3: Strain rate of right ventricle free wall of the studied groups

Click here to view


[Table 4] shows that there was a statistically highly significant correlation between PASP and other parameters:

  1. Positive (direct) highly significant correlation between IVRT and PASP (P < 0.001).
  2. Negative (inverse) highly significant correlation between FAC and PASP (P < 0.001).
  3. Negative (inverse) highly significant correlation between TAPSE and PASP (P < 0.001).
  4. Negative (inverse) highly significant correlation between SͲ wave and PASP (P < 0.001).
  5. Negative (inverse) highly significant correlation between RV free wall strain and PASP (P < 0.001).
  6. Negative (inverse) highly significant correlation between RV free wall strain rate and PASP (P < 0.001).
Table 4: Correlation between pulmonary artery systolic pressure and other parameters among patients

Click here to view



  Discussion Top


The detection of the presence of PH is important in certain clinical scenarios, such as suspected thromboembolic disease, ascites and peripheral edema of unknown origin, and unexplained dyspnea. The use of PAC is often not recommended after balancing the risks and benefits in many of these situations. Echocardiography, on the other hand, has for a long time provided an alternative for the determination of SPAP [14].

Assessment of RV function by echocardiography is challenging.

The development of technology for measurement of regional myocardial velocities by means of tissue Doppler and of software for calculation of regional deformation and deformation rate in the LV has offered researchers a promising new technology for noninvasive assessment of RV myocardial function [15].

Shortly thereafter studies reported on the applicability of tissue Doppler-based deformation analysis in the RV as well [16].

In this study, we used strain and strain rate echocardiography for assessment of the RV in patients with PH.

In our study we showed correlations between PASP and many parameters, as follows.

Tricuspid annular plane systolic excursion

There was a highly significant inverse (negative) correlation between PASP and TAPSE in our study.

Lang et al. [9] have shown that in systole the tricuspid annulus will normally descend toward the apex by 1.5-2.0 cm. Tricuspid annular excursion of less than 1.5 cm has been associated with poor prognosis in a variety of cardiovascular diseases.

The right ventricular systolic velocity (SͲ wave)

There was a highly significant inverse (negative) correlation between PASP and SͲ wave in our study.

SͲ wave is used to assess RV function.

The rate of RV dysfunction was significantly higher in patients with PAH and this is in agreement with the results of Bréchot et al. [17]

The right ventricular isovolumic relaxation time

A highly significant direct (positive) correlation existed between PASP and rIVRT measured by TDI (rIVRTͲ).

A significant correlation was found between IVRT and invasively measured PASP [18],[19].

Fahmy Elnoamany and Abdelraouf Dawood [20] have demonstrated that tricuspid annular pulsed wave TDI-derived IVRTc correlates very strongly with invasively measured PASP.

Therefore, it can be used to predict PASP.

It can even be considered as an alternative to tricuspid regurgitation-derived PASP when tricuspid regurgitation is nonrecordable.

Abbas et al. [21] demonstrated an inverse relationship between IVRT and RAP, with 80% sensitivity and 87.7% specificity for IVRT less than 59 ms to predict RAP greater than 8 mmHg.

As described in Bréchot et al. [17] after excluding patients with elevated mean RAP, the correlation between IVRT and PASP was seen to have improved (r = 0.60, P < 0.01, n = 120).

Zimbarra Cabrita et al. [22] studied 196 patients with PH and 37 controls. The etiology of PH was PAH (111 patients), veno-occlusive disease (three patients), lung disease (22 patients), chronic thromboembolic PH (54 patients), and PH with unclear/multifactorial mechanisms (six patients).

IVRT, measured by DTI, was significantly higher in PH patients than in the group with normal PASP.

As a noninvasive method, IVRT was able to distinguish between patients with and without PH, regardless of the etiology.

We identified that an IVRT cutoff of 75 ms provides high sensitivity and specificity for discriminating abnormally elevated pulmonary pressure.

Regional right ventricle strain and strain rate

In our study we have demonstrated a highly significant inverse (negative) correlation between strain and strain rate and PASP.

Consistent with our result Sachdev et al. [23] have shown that noninvasive assessment of RV longitudinal systolic strain and strain rate independently predicts future right-sided heart failure, clinical deterioration, and mortality in patients with PAH.

Kjaergaard et al. [24] demonstrated that regional deformation of the RV free wall has significant prognostic importance in a population suspected of first nonmassive pulmonary embolism, and is significantly associated with adverse events in patients with proven pulmonary embolism.

Recommendations

  1. Assessment of RV systolic and diastolic functions should be performed routinely in all patients suffering from PH.
  2. Routine study of TAPSE and right ventricle systolic excursion velocity (RVSͲ) should be conducted in every patient with PH to assess the RV systolic function.
  3. Routine assessment of the RV diastolic function by transtricuspid Doppler inflow and tissue Doppler velocity of the tricuspid annulus should be carried out for adequate assessment of the right diastolic function in patients with PH.
  4. Routine measurement of rIVRT by means of a noninvasive technique for assessment of RV functions, which overcomes the limitations of traditional echocardiography.
  5. Evaluation of strain and strain rate is a novel method for assessment of regional RV functions, which can detect early affection of the free wall of the RV.



  Acknowledgements Top


Conflicts of interest

There are no conflicts of interest.

 
  References Top

1.Nanda NC, Gramiak R, Robinson TI, et al. Echocardiographic evaluation of pulmonary hypertension. Circulation 1974; 50:575-581.  Back to cited text no. 1
    
2. Chin KM, Kim NH, Rubin LJ, et al. The right ventricle in pulmonary hypertension. Coron Artery Dis 2005; 16:13-18.  Back to cited text no. 2
    
3. Mizushige K, Morita H, Senda S, et al. Influence of right ventricular pressure overload on left and right ventricular filling in corpulmonale assessed with Doppler echocardiography. Jpn Circ J 1989; 53:1287-1296.  Back to cited text no. 3
    
4. Burgess MI, Bright-Thomas RJ, et al. Echocardiographic evaluation of right ventricular function. Eur J Echocardiogr 2002; 3:252-262.  Back to cited text no. 4
    
5. Miyatake K, Yamagishi M, Tanaka N, et al. New method for evaluating left ventricular wall motion by color-coded tissue Doppler imaging: in vitro and in vivo studies. J Am Coll Cardiol 1995; 25:717-724.  Back to cited text no. 5
    
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9. Lang RM, Bierig M, Devereux RB, et al.: Recommendations for chamber quantification: a report from the American Society of Echocardiography′s guidelines and Standards Committee and the Chamber Quantification Writing Group, Developed in Conjunction with the European Association of Echocardiography, a Branch of the European Society of Cardiology. J Am Soc Echocardiogr 2005; 18:1440-1463.  Back to cited text no. 9
    
10.Chan KL, Currie PJ, Steward JB, et al. Comparison of three Doppler ultrasound methods in the prediction of pulmonary artery pressure. J Am Cardiol 1987; 6:549-554.  Back to cited text no. 10
    
11.Berg S. Myocardial strain rate by Doppler ultrasound methods. Angle dependency and error estimation [Master′s thesis]. Department of Engineering Cybernetics, NTNU, Trondheim, Norway; 2004.  Back to cited text no. 11
    
12.Scridon T, Scridon C, Skali H, et al. Prognostic significance of troponin elevation and right ventricular enlargement in acute pulmonary embolism. Am J Cardiol 2005; 96:303-305.  Back to cited text no. 12
    
13.Sutherland GR, Di Salvo G, Claus P, et al. Strain and strain rate imaging: a new clinical approach to quantifying regional myocardial function. J Am Soc Echocardiogr 2004; 17:788-802.  Back to cited text no. 13
    
14.Yock PG, Popp RL. Noninvasive estimation of right ventricular systolic pressure by Doppler ultrasound in patients with tricuspid regurgitation. Circulation 1984; 70:657-662.  Back to cited text no. 14
    
15.Sutherland GR, Kukulski T, Voight JU, et al. Tissue Doppler echocardiography: future developments. Echocardiography 1999; 16: 509-520.  Back to cited text no. 15
    
16.Jamal F, Bergerot C, Argaud L, et al. Longitudinal strain quantitates regional right ventricular contractile function. Am J Physiol Heart Circ Physiol 2003; 285:H2842-H2847.  Back to cited text no. 16
    
17.Bréchot N, Gambotti L, Lafitte S, et al. Usefulness of right ventricular isovolumic relaxation time in predicting systolic pulmonary artery pressure. Eur J Echocardiogr 2008; 9:547-554.  Back to cited text no. 17
    
18.Lindqvist P, Waldenstrom A, Wikstrom G, et al. Right ventricular myocardial isovolumic relaxation time and pulmonary pressure. Clin Physiol Funct Imaging 2006; 26:1-8.  Back to cited text no. 18
    
19.Dambrauskaite V, Delcroix M, Claus P, et al. The evaluation of pulmonary hypertension using right ventricular myocardial isovolumic relaxation time. J Am Soc Echocardiogr 2005; 18:1113-1120.  Back to cited text no. 19
    
20.Fahmy Elnoamany M, Abdelraouf Dawood A. Right ventricular myocardial isovolumic relaxation time as novel method for evaluation of pulmonary hypertension: correlation with endothelin-1 levels. J Am Soc Echocardiogr 2007; 20:462-469.  Back to cited text no. 20
    
21.Abbas A, Lester S, Moreno FC, et al. Noninvasive assessment of right atrial pressure using Doppler tissue imaging. J Am Soc Echocardiogr 2004; 17:1155-1160.  Back to cited text no. 21
    
22.Zimbarra Cabrita I, Ruísanchez C, Grapsa J, et al. Validation of the isovolumetric relaxation time for the estimation of pulmonary systolic arterial blood pressure in chronic pulmonary hypertension. Eur Heart J Cardiovasc Imaging 2013; 14:51-55.  Back to cited text no. 22
    
23.Sachdev A, Villarraga HR, Frantz RP, et al. Right ventricular strain for prediction of survival in patients with pulmonary arterial hypertension. Chest 2011; 139:1299-1309.  Back to cited text no. 23
    
24.Kjaergaard J, Iversen KK, Vejlstrup NG, et al. Assessment of right ventricular systolic function by tissue Doppler echocardiography. Dan Med J 2012; 59:1-20.  Back to cited text no. 24
    


    Figures

  [Figure 1], [Figure 2], [Figure 3]
 
 
    Tables

  [Table 1], [Table 2], [Table 3], [Table 4]



 

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