|Ahead of print publication
Left Ventricular Function Assessment of Patients with Postoperative Ventricular Septal Defect Closure by Longitudinal Strain on Two-Dimensional Echocardiography 1 Year after Surgery
Ashish Banpurkar, Sushil Azad, Sitaraman Radhakrishnan, Ankit Garg
Department of Paediatric Cardiology, Fortis Escorts Heart Institute, New Delhi, India
|Date of Submission||21-Sep-2020|
|Date of Acceptance||29-Oct-2020|
|Date of Web Publication||24-Apr-2021|
Department of Paediatric Cardiology, Fortis Escorts Heart Institute, New Delhi - 110 025
Source of Support: None, Conflict of Interest: None
Background: Patients with large perimembranous ventricular septal defects (pm-VSDs) undergo surgical repair with prosthetic material during infancy. However, the effect of the presence of akinetic patch in the ventricular septum on the left ventricular (LV) mechanical synchrony and ventricular function has not been studied. In our study, we assessed LV function in postoperative pm-VSD closure patients on two-dimensional (2D) echocardiography (echo) after 1 year of surgery using biplane Simspon's method, fractional shortening (FS), and global longitudinal strain (GLS) to assess the regional strain pattern. Methods: This was a a single-institution observational study. Patients following up 1 year after surgical ventricular septal defect closure at our institute were enrolled. On follow-up, detailed 2D echo was done with special emphasis on left atrial size, LV size (by M-mode), and presence of any residual shunt. LV function was assessed using biplane Simpson's method and longitudinal strain on 2D echo. GLS was measured in three standard apical views. Results: Of the 121 patients enrolled, 101 patients fulfilling the inclusion and exclusion criteria were analyzed. Of these 101 patients, 75.2% were males. The median age at follow-up after surgery was 3.67 ± 2.7 years. About 92.1% of patients did not have residual VSD lesion. No patient had pulmonary arterial hypertension. All except one patient had normal ventricular function. Patients with ventricular dysfunction had LV ejection fraction (LVEF) of 47%, GLS –17.4%, and FS −20.5%. The mean values of FS, LVEF, and GLS were 32.0 ± 5.28%, 62.2% ± 4.2%, and −26.53 ± 2.93%, respectively, in pm-VSD closure patients. Regional strain pattern analysis showed significantly lower strain values in basal anteroseptal segment with a mean of −21.4 ± 2.7%. FS and GLS were noted to have significant correlation with each other (P = 0.01) and LVEF by biplane Simpson's method and GLS had significant correlation with each other (P = 0.0001). Conclusions: GLS has strong correlation with LVEF by Simson's method and FS. Basal anteroseptal segment in pm-VSD patients had significantly lower strain values compared to other segments. There is no significant correlation between age at surgery and GLS in pm-VSD closure patients who were operated within 1 year of age. The type of VSD closure does not have significant influence on GLS.
Keywords: Global longitudinal strain, perimembranous ventricular septal defect, ventricular septal defect closure
|How to cite this URL:|
Banpurkar A, Azad S, Radhakrishnan S, Garg A. Left Ventricular Function Assessment of Patients with Postoperative Ventricular Septal Defect Closure by Longitudinal Strain on Two-Dimensional Echocardiography 1 Year after Surgery. J Indian Acad Echocardiogr Cardiovasc Imaging [Epub ahead of print] [cited 2021 Jul 23]. Available from: https://www.jiaecho.org/preprintarticle.asp?id=314606
| Introduction|| |
Congenital heart diseases are the most frequent lethal malformation, affecting about 1% of newborns and causing significant morbidity and mortality in infants., Ventricular septal defect (VSD) is the most common cardiac malformation and accounts for 25% of congenital heart disease. Patients with large perimembranous VSDs (pm-VSDs) undergo surgical repair with prosthetic material during infancy. Early postoperative echocardiograms of these patients routinely demonstrate paradoxical septal motion and depressed regional left ventricular (LV) function. However, the effect of the presence of akinetic patch in the ventricular septum on the LV mechanical synchrony and ventricular function has not been studied. These patients are evaluated on follow-up with conventional echocardiographic parameters. However, there are limitations with conventional methods of ventricular function assessment on echocardiography (echo). Recently, it has been documented that global longitudinal strain (GLS) assessed by two-dimensional (2D) speckle tracing is better correlated with LV ejection fraction (LVEF) assessed by magnetic resonance imaging than LVEF assessed by echo, especially in patients with poor acoustic windows. Limited data exist for delayed LV function assessment in postoperative pm-VSD closure patients with respect to regional myocardial functional assessment. In our study, we assessed LV function in postoperative pm-VSD closure patients on 2D echo after 1 year of surgery using biplane Simspon's method, fractional shortening (FS), and GLS.
| Methods|| |
Design of study and participants
The present study was a single-center, observational study in which consecutive eligible patients were included during the period starting from August 2017 to May 2019.
Aims and objectives
The aims and objectives were to access the LV function in postoperative patients with VSD by longitudinal strain on 2D echo after 1 year of surgery and to assess the regional strain pattern in pm-VSD patients after 1 year of surgery.
Patients with a history of isolated pm-VSD who underwent surgery within the 1st year of life and following up at least 1 year postsurgery were included in the study.
VSD associated with additional intra-cardiac lesions other than mild atrioventricular valve regurgitation or semilunar valve regurgitation. Patients with significant residual VSD, pulmonary arterial hypertension, and conduction abnormality on electrocardiogram like left bundle branch block and systemic condition which would affect the cardiac function were also excluded from the study.
Detailed 2D echo was done with special emphasis on left atrial (LA) size, LV size (by M-mode), and presence of any residual shunt. LV function was recorded using biplane Simpson's method and longitudinal strain on 2D echo. For FS, the normal value ranges between 28% and 38%. Normal values for LVEF were considered between 54% and 75%. For measurement of LV function by longitudinal strain, after optimizing image quality, maximizing frame rate, and minimizing forshortening, GLS measurement was made in three standard apical views and averaged. All GLS measurements were performed using PHILIPS EPIQ 7 machine using the same software (QLAB, Philips Ultrasound 22100 Bothell-Everett Highway Bothell, WA 98021- 8431 USA) for all patients.
Descriptive statistics were used to define demographic and baseline variables. Continuous data were presented as mean ± standard deviation or median (range) and dichotomous data as percentage. The distribution of the data was tested by Kolmogorov–Smirnov test. The continuous data were compared using a Student's t-test for normally distributed data and Mann–Whitney test for skewed data. The dichotomous data were compared using Chi-square test or Fisher's exact test wherever applicable. Pearson's correlation was used to correlate different methods of ventricular function assessment. ANOVA test was used to compare the regional strain pattern in different types of VSD closure patients. P < 0.05 was considered significant. Statistical analysis was performed using IBM SPSS Statistics for Windows, version 25 (IBM, Armonk, New York, USA).
| Results|| |
We enrolled a total of 121 patients of VSD closure, who were operated within 1 year of age and were following-up after 1 year of surgery. Of 121 patients, 101 patients were of pm-VSD, 11 patients of muscular VSD, and 9 patients of doubly committed VSD. Hundred and one pm-VSD closure patients were analyzed. Patients' characteristics are presented in [Table 1].
Echocardiographic parameters at the point of evaluation are summarized in [Table 2].
Left ventricular function assessment
All patients had normal LV function except one. Mean FS, LVEF, and GLS in our study population were 32.0 ± 5.28%, 62.2% ± 4.2%, and 26.53 ± 2.93%, respectively. The patient with LV dysfunction had FS 20.5%, LVEF by Simpson's method 47%, and GLS - 17.4%. End-diastolic volume and end-systolic volume in this patient were 76 ml and 40.3 ml, respectively.
FS and LVEF were noted to have a significant positive correlation (P = 0.0001). GLS also had a positive correlation with FS which was statistically significant (P = 0.01) [Figure 1] and GLS had a statistically significant correlation with LVEF calculated by Simpson's method (P = 0.0001) [Figure 2].
|Figure 1: Scatter diagram showing positive correlation between global longitudinal strain and fractional shortening which was statistically significant (P = 0.01). FS: Fractional shortening, GLS: Global longitudinal strain|
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|Figure 2: Scatter diagram showing that global longitudinal strain had a statistically significant correlation with left ventricular ejection fraction calculated by Simpson's method (P = 0.0001). EF: Ejection fraction, GLS: Global longitudinal strain|
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Regional left ventricular longitudinal function
Segment-wise pattern in pm-VSD patients is summarized in [Table 3]. The LV longitudinal strain measured was homogeneous for all segments except basal anteroseptal when compared with respect to the type of VSD closed. The basal anteroseptal segment had statistically significant lower strain values compared to other segments (P = 0.035). The mean value of GLS was −26.53 ± 2.93%, while the mean longitudinal strain in the basal anteroseptal segment was −21.4 ± 2.70%.
|Table 3: Global longitudinal strain and segment-wise strain pattern in perimembranous ventricular septal defects patients|
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Influence of age at surgery, age at evaluation, and type of ventricular septal defect on strain measurements
GLS was compared between the two groups depending on the age at surgery, i.e., below 6 months and above 6 months. GLS in below 6-month age group was −26.50 ± 2.34%, while in 6 months to 1-year group, it was −26.53 ± 3.19%. GLS did not correlate significantly with the age at surgery (P = 0.94). Patients were also divided into three age groups based on the age at evaluation and GLS was measured in these groups and compared. Of 101 patients, 50 (49.3%) were between 1 and 4 year age group, 38 (37.3%) patients were in 5–9 years age group, and 13 (12.3%) patients were in more than 10 years age group; GLS measured in these groups was −27.0 ± 2.6%, −26.1 ± 3.4%, and −25.7 ± 2.3%, respectively. There was no significant correlation between the age at evaluation and GLS noted in our study. GLS was also compared in the three groups depending on the type of VSD closure. GLS in pm-VSD closure, muscular VSD, and doubly committed VSD was −26.53 ± 2.93%, −26.19 ± 3.38%, and −27.17 ± 3.05%, respectively. There was no significant correlation between the type of VSD closure and GLS (P = 0.761).
| Discussion|| |
Echo has become the most important noninvasive technique for the diagnosis and follow-up of congenital heart disease in children. Different echocardiographic techniques have been developed that allow a more detailed analysis of cardiac function. Speckle-tracking-based strain imaging provides direct quantitative information about myocardial motion and deformation, which is more geometry independent than measurement of ejection fraction. This is the first study to describe the use of strain by speckle tracking for assessment of LV function after surgical closure of VSD and to describe regional longitudinal systolic strain in pm-VSD closure patients.
Ventricular function assessment
Our study showed excellent correlation among FS, LVEF by Simpson's biplane method and GLS for assessment of LV systolic function in post-pm-VSD closure patients.
All except one patient (i.e. 99% of the patients) had normal LV function. Our results were comparable to the data described by Roos-Hesselink et al. reporting normal LVEF in 96% cases. Furthermore, normal LVEF was reported by Reddy et al. in all postoperative VSD closure patients in their study population, while the study by Meijboom et al. reported 86% of patients having normal LV function and dimensions. A slight difference in results may be due to varying timing of evaluation and inclusion and exclusion criteria. In our study, we excluded patients following-up within 1 year of surgery. The mean interval between surgery and the time of evaluation in our study was 3.67 ± 2.7 years.
The mean LVEF with Simspon's method was 62.2% ± 4.2% in pm-VSD closure patients. Similar results were shown by Reddy et al. in 2009, who noted a mean LVEF of 53.8 ± 6% in VSD closure patients without any conduction abnormality evaluated at 5–10 years after VSD closure. The mean FS noted in our study was 32.01 ± 5.28% which is comparable with the normal values of FS. The normal value of FS ranges between 28% and 38%. FS and LVEF were noted to have a significant correlation (P = 0.0001).
The mean GLS in pm-VSD patients was −26.53 ± 2.93%. These results are comparable with the GLS in healthy individuals reported by Bussadori et al. with a mean GLS of −22.18 ± 3.06%. A comparison of GLS and segmental strain in various studies is provided in [Table 4].
|Table 4: Comparison of regional left ventricular strain pattern in different studies|
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GLS had a statistically significant correlation with LVEF calculated by Simpson's method (P = 0.0001). A similar correlation was noted by Stanton et al. who studied an adult population in 2009, and concluded that GLS and LVEF were highly significantly correlated. GLS also had a positive correlation with FS which was statistically significant (P = 0.01).
The minimum age at surgery in our study population was 2 months and maximum was 1 year. The mean age at operation was 7.2 months. The mean age at surgery in the study by Bol-Raap et al. was 1.8 years, ranging from 2.5 weeks to 14.8 years. This difference in the age at surgery between our study and the study by Bol-Raap et al. is explained by the fact that we had excluded all the patients who were operated beyond 1 year of age.
Influence of age at surgery, age at evaluation, and type of ventricular septal defect on global longitudinal strain
In this study, we noted that age at surgery, age at evaluation, and type of VSD closure done did not have a significant influence on the measurement of GLS. In our study, GLS values in patients of 1–4 year age group, 5–9 year age group, and in more than 10 years age groups were −27.0% ± 2.6%, −26.1% ± 3.4%, and −25.7% ± 2.3%, respectively, while Forsey et al. noted GLS in healthy individuals in these age group as −20.7% ± 1.3%, −21.0% ± 1.3%, and −21.8% ± 1.3%, respectively. Variability noted in GLS values may be due to different patient profiles, operator variability, or due to vendor differences. Normal values of GLS in different age groups as noted by Farsey et al. are compared with our study in [Table 5].
Regional left ventricular longitudinal function assessment
We noted that basal anteroseptal segment had statistically significant lower strain values compared to other segments in pm-VSD patients. The mean value of GLS was −26.53% ± 2.95%, while the mean longitudinal strain in the basal anteroseptal segment was −21.7% ± 2.84%. This segment corresponds to the location of VSD patch in pm-VSD closure patients. Hence, this lower value of regional strain in the basal anteroseptal segment was likely to be due to the akinetic patch in that region. Long-term study should be done using strain imaging to assess the effect of akinetic patch on myocardial function, especially related to mechanical dyssynchrony.
A comparison of regional LV strain pattern in different studies is tabulated in [Table 4].
Limitations of the study
We have studied regional strain patterns in pm-VSD closure patients at 1 year after surgery. However, mechanical dyssynchrony related to akinetic patch is supposed to occur after a longer duration after akinetic patch placement. Long-term study is required to access the mechanical dyssynchrony with GLS. We have assessed pm-VSD closure patient with GLS only one time. Serial assessment in patients with akinetic patch would help to delineate the changes associated with it.
| Conclusions|| |
GLS had a strong correlation with LVEF by Simson's method and FS. The basal anteroseptal segment in pm-VSD patients had significantly lower strain values compared to other segments. There was no significant correlation between age at surgery and GLS in pm-VSD closure patients who were operated within 1 year of age. The type of VSD closure did not have a significant influence on GLS.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]