Risk Factors for Late Right Ventricular Systolic Dysfunction in Pediatric Patients With Repaired Tetralogy of Fallot Qiang Ji,1 MD, Yunqing Mei,1 MD, Xisheng Wang,1 MD, Jing Feng,1 MD, and Wenjun Ding,2 MD Summary To evaluate independent risk factors for late right ventricular systolic dysfunction after correction of Tetralogy of Fallot (TOF) in a single-centre, retrospective and observational clinical trial. Patients less than 3 years of age who underwent correction of TOF and subsequently routine clinical follow-up of more than 36 months were included in this study and were divided either into an experimental group (right ventricular systolic dysfunction) or a control group (normal right ventricular systolic function) according to the tricuspid annular peak systolic velocity (TAPSV) value measured by pulsed wave-tissue Doppler imaging (pulsed wave-TDI). The relevant data of all selected patients were investigated and analyzed. From January 2012 to December 2012, a total of 113 consecutive eligible patients were enrolled in this study and were divided either into an experimental group (n = 41) or control group (n = 72). Through univariate analysis and subsequent logistic regression, low preoperative arterial oxygen saturation (OR = 1.66, 95%CI 1.22-4.58, P = 0.0163), age less than 6 months at the time of surgery (OR = 3.45, 95%CI 1.87-9.17, P = 0.0021), and transannular patch (OR = 2.15, 95%CI 1.31-5.38, P = 0.0015) were 3 independent risk factors for late right ventricular systolic dysfunction after correction of TOF. This clinical trial suggested low preoperative arterial oxygen saturation was associated with late right ventricular systolic dysfunction after correction of TOF, and appropriate age at the time of surgery and selection of a proper surgical method to reconstruct the right ventricular outflow tract contributed to improving late right ventricular systolic function in pediatric patients with repaired TOF. (Int Heart J 2015; 56: 80-85) Key words: Tricuspid annular peak systolic velocity, Pulsed wave-tissue Doppler imaging, Transannular patch
T
etralogy of Fallot (TOF) is the most common cyanotic congenital heart defect with a prevalence of 0.5 per 1000 live births, and represents approximately 9% of all congenital heart defects.1) Right ventricular systolic dysfunction is a common problem in patients with repaired TOF, and is closely related with quality-of-life, late morbidity, and mortality.2) Hence, it is crucial for the clinician to evaluate risk factors for late right ventricular systolic dysfunction after correction of TOF, in order to improve clinical outcomes. The measurement of myocardial velocities using tissue Doppler imaging (TDI) is a promising approach for the quantitative noninvasive assessment of longitudinal systolic ventricular performance.3) New indices for noninvasive assessment of right ventricular systolic function have been described, such as tricuspid annular plane systolic excursion,4) right ventricular myocardial performance index (MPI), and tricuspid annular peak systolic velocity (TAPSV).5) TAPSV, measured by pulsed wave-tissue Doppler imaging (pulsed wave-TDI), has been suggested as a good quantitative parameter of right ventricular
systolic function in children.6-8) A few more recent studies have shown that TAPSV may be a reproducible index of right ventricular systolic function in patients with corrected congenital heart disease,9) including repaired TOF.10) Thus far, few reports have focused on evaluating risk factors for late right ventricular systolic dysfunction after correction of TOF through non-invasive examination. Since it has been accepted as a good noninvasive evaluating indicator of right ventricular systolic function in pediatric patients with repaired TOF, TAPSV, measured by pulsed wave-TDI, may be a promising index of right ventricular systolic function in pediatric patients with repaired TOF. Based on the above analysis, this study reviewed 113 pediatric patients with repaired TOF and aimed to evaluate independent risk factors for late right ventricular systolic dysfunction after correction of TOF by using TAPSV as an evaluating indicator of right ventricular systolic function.
From the 1 Department of Thoracic Cardiovascular Surgery of Tongji Hospital of Tongji University and 2 Department of Cardiovascular Surgery of Zhongshan Hospital of Fudan University, Shanghai, P.R. China. Address for correspondence: Yunqing Mei, MD, Department of Thoracic Cardiovascular Surgery, Tongji Hospital, Tongji University, Shanghai. 389 Xincun Rd., Shanghai, 200065, P.R. China. E-mail: [email protected] or WenJun Ding, MD, Department of Cardiovascular Surgery, Zhongshan Hospital of Fudan University, Shanghai. 180 Fenglin Rd., Shanghai, 200032, P.R. China. E-mail: [email protected] Received for publication May 14, 2014. Revised and accepted June 22, 2014. Released in advance online on J-STAGE December 11, 2014. All rights reserved by the International Heart Journal Association. 80
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Methods Eligible patients were as follows: 1) less than 3 years of age at the time of surgery; and 2) undergoing correction of TOF and later routine clinical follow-up of more than 36 months. Those patients with restrictive physiology of the right ventricle, which was defined as the presence of laminar antegrade diastolic main pulmonary artery flow throughout the respiratory cycle by Doppler echocardiography, were excluded. Patients with tricuspid regurgitation and a ventricular septal defect residual shunt during follow-up were also excluded. Echocardiography: All patients underwent echocardiography within 3 days before surgery and at the follow-up evaluation. Echocardiography was conducted using a commercially available echocardiographic system (Sonos iE33, Philips, Andover, MA, USA) with transducers of 5-1, 8-3, and 12-4 MHz, depending on patient size. The images were recorded digitally and later analyzed by one of the investigators using off-line software (Xcelera Echo, Philips Medical Systems, Eindhoven, Netherlands). The investigation of TAPSV was conducted in a quiet state. Pulsed wave-TDI of the lateral tricuspid annulus was conducted using transducer frequencies of 2.5 to 3.5 MHz, with spectral Doppler filters adjusted to a Nyquist limit of 15 to 20 cm/s. The minimal optimal gain setting was used. Doppler measurements were acquired with the subjects in the left lateral decubitus position during shallow respiration. Guided by the 4-chamber view, a 5-mm sample volume was placed at the lateral corner of the tricuspid annulus at the attachment of the anterior leaflet of the tricuspid valve. Care was taken to obtain an ultrasound scan as parallel as possible to the direction of the tricuspid annular motion. The peak annular velocities during systole were recorded and analyzed off-line. The resulting velocities were measured from 3 well-trained observers from 5 consecutive cardiac cycles and averaged. Research protocol: This study protocol was approved by the ethics committee of Tongji hospital affiliated to Tongji University and was consistent with the “Declaration of Helsinki”. The guardians of patients selected signed an informed consent form approved by the ethics committee. All patients selected were divided into either an experimental group (right ventricular systolic dysfunction group) or a control group (normal right ventricular systolic function group) according to a TAPSV value measured at the last follow-up evaluation. With reference to previous reports,11) in which the dividing TAPSV value (the dividing value was calculated as 7.353 + 3.157 × AGE1/2 - 0.388 × AGE) was taken as a cut-off point to discriminate between normal and impaired right ventricular systolic function, we used the same criterion in this study to describe normal and impaired right ventricular systolic function, that is, a TAPSV value of less than the dividing value was defined as impaired right ventricular systolic function and that of more than the dividing value was defined as normal right ventricular systolic function. The relevant data of all selected patients were investigated and analyzed. Preoperative information included age, gender, weight, hemoglobin, prior aortopulmonary shunt surgery, arterial oxygen saturation (in absence of supplemental oxygen administration), arrhythmia, McGoon ratio, Nakata index, aortic overriding degree, size of ventricular septal defect, maximal pressure gradient between right ventricular outflow tract and Subjects:
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RV SYSTOLIC DYSFUNCTION AFTER REPAIRED TOF
pulmonary valve (RVOT-PG max), ratio between tricuspid peak early diastolic velocity and tricuspid peak late diastolic velocity, tricuspid regurgitation, left ventricular end-diastolic volume index (LVEDVI), left ventricular ejection fraction (LVEF), ratio between mitral peak early diastolic velocity and mitral peak late diastolic velocity, and associated malformations. Intraoperative variables included mode of right ventricular outflow tract reconstruction (transannular patch or not), duration of cardiopulmonary bypass (CPB) and aortic cross clamping (ACC), and lowest nasopharyngeal temperature as well as rectal temperature. Early postoperative data included redo surgery for bleeding, low cardiac output (need for inotropic support with vasoactive drugs (dopamine 4 μg/kg/ minute at least for a minimum of 12 hours and/or dobutamine) to maintain systolic blood pressure greater than 90 mmHg and signs of impairment of body perfusion – cold extremities, hypotension, oliguria/anuria, lowered level of consciousness or a combination of these signs), respiratory failure (prolonged ventilator therapy (> 72 hours) or re-intubation), peritoneal dialysis, length of intensive care unit (ICU) stay, and right ventricular outflow tract residual obstruction (gradient over 20 mmHg) as well as pulmonary regurgitation before discharge. All selected patients were followed up for at least 36 months after correction of TOF. Physical examination, electrocardiogram, chest X-ray, and echocardiography were used for followup evaluation. Age, NYHA class, recurrent pleural effusion, incomplete right bundle-branch block, right ventricular outflow tract residual obstruction, pulmonary regurgitation, LVEF, and ratio between tricuspid peak early diastolic velocity and tricuspid peak late diastolic velocity at the last follow-up evaluation were recorded. The duration between correction of TOF and the last follow-up evaluation was also recorded. The severity of pulmonary regurgitation was judged by color flow pulmonary regurgitation jet width measured by echo-Doppler: mild, small, usually < 10 mm in length with a narrow origin; severe, large, with a wide origin, may be brief in duration; moderate, intermediate. Statistical analysis: Statistical analysis was performed using the SPSS 13.0 statistical software package (SPSS Inc, Chicago, IL). Data are expressed as the mean ± standard deviation for continuous variables, and frequencies for categorical variables. Univariate analysis, using the unpaired t-test according to homogeneity testing for variance to compare measurement data and Fisher’s exact test to compare enumeration data, was conducted to assess statistically significant variables. Those with P < 0.10 obtained through univariate analysis were then entered into a logistic regression analysis to identify independent risk factors for late right ventricular dysfunction after correction of TOF. A P value less than 0.05 was considered statistically significant.
Results Study population: From January 2012 to December 2012, after obtaining approval by the ethic committee and written informed consent, a total of 120 consecutive pediatric patients less than 3 years of age who underwent correction of TOF and later clinical follow-up of more than 36 months were enrolled in this study. Seven patients were excluded (ventricular septal defect residual shunt during follow-up in 1 patient, moderate
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to severe tricuspid regurgitation during follow-up in 2 patients, hospital death in 3 patients (2 patients died of postoperative low cardiac output and 1 of perfusion lung), and sudden death 25 months after surgery in 1 patient) so 113 pediatric patients were analyzed. According to the TAPSV value measured by pulsed wave-TDI, these 113 eligible pediatric patients were divided either into an experimental group (n = 41) or into a control group (n = 72). Associated malformations were observed in 38 (33.6%) patients. The associated malformations were as follows: secundum atrial septal defect (18 patients), patent ductus arteriosus (14), left superior vena cava (7), anomalous origin of the coronary artery (3), and atrioventricular septal defect (1). The characteristics of selected patients are shown in Table I. There were significant differences in age and weight at the time of surgery, preoperative arterial oxygen saturation, and preoperative RVOT-PG max between the two groups. Intra-operative data: During surgical procedures, the mean cardiopulmonary bypass time and mean myocardial ischemic time were 94.6 ± 18.6 minutes and 63.7 ± 14.4 minutes, respectively. Ventricular septal defect was repaired through the right atrium in 75 patients (66.4%), right ventriculotomy in 26 (23.0%), right atrium and right ventriculotomy in 10 (8.9%),
and right atrium and pulmonary artery in 2 patients (1.8%). Seventy patients (61.9%) received a transannular patch made of autologous pericardium or bovine pericardium with or without pulmonary valve repair to reconstruct the right ventricular outflow tract. Reconstruction procedures of the right ventricular outflow tract were classified as follows: infundibulectomy only in 3 patients (2.7%), right ventricular patch with or without infundibulectomy in 40 (35.4%), transannular incision with a transannular patch in 49 (43.4%), and transannular incision with pulmonary valve repair in 21 (18.6%). None of the patients received a right ventricle-pulmonary artery conduit technique. As shown in Table II, there was a significant difference in the mode of right ventricular outflow tract reconstruction (transannular patch or not) between the experimental group and the control group. Postoperative data: In the early postoperative period, 5 patients underwent redo surgery for bleeding, 22 patients developed postoperative low cardiac output, 19 patients developed respiratory failure, and 15 patients underwent peritoneal dialysis. Right ventricular outflow tract residual obstruction was observed in 19 patients and pulmonary regurgitation in 42 patients (mild pulmonary regurgitation in 32 patients and
Table I. Characteristics of Study Patients
Age (months) Age < 6 months Gender (male/female) Weight (kg) Hemoglobin (g/L) Prior aortopulmonary shunt surgery Arterial oxygen saturation (%) Arterial oxygen saturation < 60% Arrhythmia McGoon ratio Nakata index (mm2/m2) Aortic overriding degree (%) Size of VSD (mm) RVOT-PG max (mmHg) TEV/TAV < 1.0 Tricuspid regurgitation LVEDVI LVEF MEV/MAV < 1.0 (%) Associated malformations
Experimental group (n = 41)
Control group (n = 72)
P
14 ± 5 13 (31.7%) 29/12 8.8 ± 1.8 171.5 ± 31.3 5 (12.2%) 65.9 ± 8.8 30 (73.2%) 3 (7.3%) 1.57 ± 0.31 168 ± 36 48.6 ± 7.6 18.5 ± 4.8 95.4 ± 15.9 15 (36.6%) 29 (70.7%) 38.5 ± 6.4 61.2 ± 8.1 10 (24.4%) 12 (29.3%)
18 ± 6 7 (9.7%) 49/23 10.5 ± 2.6 162.3 ± 27.7 11 (15.3%) 73.3 ± 10.5 28 (38.9%) 4 (5.5%) 1.68 ± 0.36 172 ± 44 46.5 ± 7.7 17.9 ± 3.9 85.7 ± 13.3 18 (25.0%) 41 (56.9%) 40.1 ± 7.2 63.8 ± 9.6 10 (13.9%) 26 (36.1%)
0.0027 0.0047 0.8345 0.0003 0.1083 0.7825 0.0002 0.0008 0.7029 0.1038 0.6215 0.1642 0.3205 0.0007 0.2045 0.1636 0.2401 0.4045 0.2015 0.5370
Experimental group indicates right ventricular systolic dysfunction group; Control group, normal right ventricular systolic function group; VSD, ventricular septal defect; RVOT, right ventricular outflow tract; TEV/TAV, ratio between tricuspid peak early diastolic velocity and tricuspid peak late diastolic velocity; LVEDVI, left ventricular end-diastolic volume index; LVEF, left ventricular ejection fraction; and MEV/MAV, ratio between mitral peak early diastolic velocity and mitral peak late diastolic velocity. Table II. Intra-Operative Data Experimental group (n = 41) Transannular patch CPB time (minutes) ACC time (minutes) Lowest nasopharyngeal temperature (°C) Lowest rectal temperature (°C)
33 (80.5%) 98.4 ± 18.6 66.5 ± 14.1 25.4 ± 4.1 27.3 ± 3.9
CPB indicates cardiopulmonary bypass; and ACC, aortic cross clamping.
Control group (n = 72) 37 (51.4%) 92.5 ± 18.5 62.5 ± 14.6 25.8 ± 4.3 26.9 ± 4.1
P 0.0025 0.1066 0.1591 0.6297 0.6129
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moderate in 10 patients) by echocardiography before discharge. During follow-up after hospital discharge, 2 patients died (1 of infective endocarditis 39 months after surgery, the other of sudden death 41 months after surgery), and the remaining patients survived, with New York Heart Association class I (93 patients) and II (18 patients). Recurrent pleural effusion was observed in 7 patients, incomplete right bundle-branch block in 61 patients, right ventricular outflow tract residual obstruction in 35 patients, and pulmonary regurgitation in 62 patients (mild pulmonary regurgitation in 32, moderate in 10, and severe in 2) during follow-up. The postoperative data of the patients are shown in Table III. It can be observed that postoperative peritoneal dialysis, incomplete right bundle-branch block, age, pulmonary regurgitation, and RVOT residual obstruction at the last follow-up evaluation were 5 relative risk factors for late right ventricular systolic dysfunction after correction of TOF. Compared with the control group, the experimental group had a higher incidence of recurrent pleural effusion after correction of TOF. Logistic regression analysis: The variables with P < 0.10 obtained through univariate analysis were then entered into multivariate logistic regression analysis (right ventricular systolic dysfunction or not as independent variable, variables with P
T
etralogy of Fallot (TOF) is the most common cyanotic congenital heart defect with a prevalence of 0.5 per 1000 live births, and represents approximately 9% of all congenital heart defects.1) Right ventricular systolic dysfunction is a common problem in patients with repaired TOF, and is closely related with quality-of-life, late morbidity, and mortality.2) Hence, it is crucial for the clinician to evaluate risk factors for late right ventricular systolic dysfunction after correction of TOF, in order to improve clinical outcomes. The measurement of myocardial velocities using tissue Doppler imaging (TDI) is a promising approach for the quantitative noninvasive assessment of longitudinal systolic ventricular performance.3) New indices for noninvasive assessment of right ventricular systolic function have been described, such as tricuspid annular plane systolic excursion,4) right ventricular myocardial performance index (MPI), and tricuspid annular peak systolic velocity (TAPSV).5) TAPSV, measured by pulsed wave-tissue Doppler imaging (pulsed wave-TDI), has been suggested as a good quantitative parameter of right ventricular
systolic function in children.6-8) A few more recent studies have shown that TAPSV may be a reproducible index of right ventricular systolic function in patients with corrected congenital heart disease,9) including repaired TOF.10) Thus far, few reports have focused on evaluating risk factors for late right ventricular systolic dysfunction after correction of TOF through non-invasive examination. Since it has been accepted as a good noninvasive evaluating indicator of right ventricular systolic function in pediatric patients with repaired TOF, TAPSV, measured by pulsed wave-TDI, may be a promising index of right ventricular systolic function in pediatric patients with repaired TOF. Based on the above analysis, this study reviewed 113 pediatric patients with repaired TOF and aimed to evaluate independent risk factors for late right ventricular systolic dysfunction after correction of TOF by using TAPSV as an evaluating indicator of right ventricular systolic function.
From the 1 Department of Thoracic Cardiovascular Surgery of Tongji Hospital of Tongji University and 2 Department of Cardiovascular Surgery of Zhongshan Hospital of Fudan University, Shanghai, P.R. China. Address for correspondence: Yunqing Mei, MD, Department of Thoracic Cardiovascular Surgery, Tongji Hospital, Tongji University, Shanghai. 389 Xincun Rd., Shanghai, 200065, P.R. China. E-mail: [email protected] or WenJun Ding, MD, Department of Cardiovascular Surgery, Zhongshan Hospital of Fudan University, Shanghai. 180 Fenglin Rd., Shanghai, 200032, P.R. China. E-mail: [email protected] Received for publication May 14, 2014. Revised and accepted June 22, 2014. Released in advance online on J-STAGE December 11, 2014. All rights reserved by the International Heart Journal Association. 80
Vol 56 No 1
Methods Eligible patients were as follows: 1) less than 3 years of age at the time of surgery; and 2) undergoing correction of TOF and later routine clinical follow-up of more than 36 months. Those patients with restrictive physiology of the right ventricle, which was defined as the presence of laminar antegrade diastolic main pulmonary artery flow throughout the respiratory cycle by Doppler echocardiography, were excluded. Patients with tricuspid regurgitation and a ventricular septal defect residual shunt during follow-up were also excluded. Echocardiography: All patients underwent echocardiography within 3 days before surgery and at the follow-up evaluation. Echocardiography was conducted using a commercially available echocardiographic system (Sonos iE33, Philips, Andover, MA, USA) with transducers of 5-1, 8-3, and 12-4 MHz, depending on patient size. The images were recorded digitally and later analyzed by one of the investigators using off-line software (Xcelera Echo, Philips Medical Systems, Eindhoven, Netherlands). The investigation of TAPSV was conducted in a quiet state. Pulsed wave-TDI of the lateral tricuspid annulus was conducted using transducer frequencies of 2.5 to 3.5 MHz, with spectral Doppler filters adjusted to a Nyquist limit of 15 to 20 cm/s. The minimal optimal gain setting was used. Doppler measurements were acquired with the subjects in the left lateral decubitus position during shallow respiration. Guided by the 4-chamber view, a 5-mm sample volume was placed at the lateral corner of the tricuspid annulus at the attachment of the anterior leaflet of the tricuspid valve. Care was taken to obtain an ultrasound scan as parallel as possible to the direction of the tricuspid annular motion. The peak annular velocities during systole were recorded and analyzed off-line. The resulting velocities were measured from 3 well-trained observers from 5 consecutive cardiac cycles and averaged. Research protocol: This study protocol was approved by the ethics committee of Tongji hospital affiliated to Tongji University and was consistent with the “Declaration of Helsinki”. The guardians of patients selected signed an informed consent form approved by the ethics committee. All patients selected were divided into either an experimental group (right ventricular systolic dysfunction group) or a control group (normal right ventricular systolic function group) according to a TAPSV value measured at the last follow-up evaluation. With reference to previous reports,11) in which the dividing TAPSV value (the dividing value was calculated as 7.353 + 3.157 × AGE1/2 - 0.388 × AGE) was taken as a cut-off point to discriminate between normal and impaired right ventricular systolic function, we used the same criterion in this study to describe normal and impaired right ventricular systolic function, that is, a TAPSV value of less than the dividing value was defined as impaired right ventricular systolic function and that of more than the dividing value was defined as normal right ventricular systolic function. The relevant data of all selected patients were investigated and analyzed. Preoperative information included age, gender, weight, hemoglobin, prior aortopulmonary shunt surgery, arterial oxygen saturation (in absence of supplemental oxygen administration), arrhythmia, McGoon ratio, Nakata index, aortic overriding degree, size of ventricular septal defect, maximal pressure gradient between right ventricular outflow tract and Subjects:
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RV SYSTOLIC DYSFUNCTION AFTER REPAIRED TOF
pulmonary valve (RVOT-PG max), ratio between tricuspid peak early diastolic velocity and tricuspid peak late diastolic velocity, tricuspid regurgitation, left ventricular end-diastolic volume index (LVEDVI), left ventricular ejection fraction (LVEF), ratio between mitral peak early diastolic velocity and mitral peak late diastolic velocity, and associated malformations. Intraoperative variables included mode of right ventricular outflow tract reconstruction (transannular patch or not), duration of cardiopulmonary bypass (CPB) and aortic cross clamping (ACC), and lowest nasopharyngeal temperature as well as rectal temperature. Early postoperative data included redo surgery for bleeding, low cardiac output (need for inotropic support with vasoactive drugs (dopamine 4 μg/kg/ minute at least for a minimum of 12 hours and/or dobutamine) to maintain systolic blood pressure greater than 90 mmHg and signs of impairment of body perfusion – cold extremities, hypotension, oliguria/anuria, lowered level of consciousness or a combination of these signs), respiratory failure (prolonged ventilator therapy (> 72 hours) or re-intubation), peritoneal dialysis, length of intensive care unit (ICU) stay, and right ventricular outflow tract residual obstruction (gradient over 20 mmHg) as well as pulmonary regurgitation before discharge. All selected patients were followed up for at least 36 months after correction of TOF. Physical examination, electrocardiogram, chest X-ray, and echocardiography were used for followup evaluation. Age, NYHA class, recurrent pleural effusion, incomplete right bundle-branch block, right ventricular outflow tract residual obstruction, pulmonary regurgitation, LVEF, and ratio between tricuspid peak early diastolic velocity and tricuspid peak late diastolic velocity at the last follow-up evaluation were recorded. The duration between correction of TOF and the last follow-up evaluation was also recorded. The severity of pulmonary regurgitation was judged by color flow pulmonary regurgitation jet width measured by echo-Doppler: mild, small, usually < 10 mm in length with a narrow origin; severe, large, with a wide origin, may be brief in duration; moderate, intermediate. Statistical analysis: Statistical analysis was performed using the SPSS 13.0 statistical software package (SPSS Inc, Chicago, IL). Data are expressed as the mean ± standard deviation for continuous variables, and frequencies for categorical variables. Univariate analysis, using the unpaired t-test according to homogeneity testing for variance to compare measurement data and Fisher’s exact test to compare enumeration data, was conducted to assess statistically significant variables. Those with P < 0.10 obtained through univariate analysis were then entered into a logistic regression analysis to identify independent risk factors for late right ventricular dysfunction after correction of TOF. A P value less than 0.05 was considered statistically significant.
Results Study population: From January 2012 to December 2012, after obtaining approval by the ethic committee and written informed consent, a total of 120 consecutive pediatric patients less than 3 years of age who underwent correction of TOF and later clinical follow-up of more than 36 months were enrolled in this study. Seven patients were excluded (ventricular septal defect residual shunt during follow-up in 1 patient, moderate
82
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to severe tricuspid regurgitation during follow-up in 2 patients, hospital death in 3 patients (2 patients died of postoperative low cardiac output and 1 of perfusion lung), and sudden death 25 months after surgery in 1 patient) so 113 pediatric patients were analyzed. According to the TAPSV value measured by pulsed wave-TDI, these 113 eligible pediatric patients were divided either into an experimental group (n = 41) or into a control group (n = 72). Associated malformations were observed in 38 (33.6%) patients. The associated malformations were as follows: secundum atrial septal defect (18 patients), patent ductus arteriosus (14), left superior vena cava (7), anomalous origin of the coronary artery (3), and atrioventricular septal defect (1). The characteristics of selected patients are shown in Table I. There were significant differences in age and weight at the time of surgery, preoperative arterial oxygen saturation, and preoperative RVOT-PG max between the two groups. Intra-operative data: During surgical procedures, the mean cardiopulmonary bypass time and mean myocardial ischemic time were 94.6 ± 18.6 minutes and 63.7 ± 14.4 minutes, respectively. Ventricular septal defect was repaired through the right atrium in 75 patients (66.4%), right ventriculotomy in 26 (23.0%), right atrium and right ventriculotomy in 10 (8.9%),
and right atrium and pulmonary artery in 2 patients (1.8%). Seventy patients (61.9%) received a transannular patch made of autologous pericardium or bovine pericardium with or without pulmonary valve repair to reconstruct the right ventricular outflow tract. Reconstruction procedures of the right ventricular outflow tract were classified as follows: infundibulectomy only in 3 patients (2.7%), right ventricular patch with or without infundibulectomy in 40 (35.4%), transannular incision with a transannular patch in 49 (43.4%), and transannular incision with pulmonary valve repair in 21 (18.6%). None of the patients received a right ventricle-pulmonary artery conduit technique. As shown in Table II, there was a significant difference in the mode of right ventricular outflow tract reconstruction (transannular patch or not) between the experimental group and the control group. Postoperative data: In the early postoperative period, 5 patients underwent redo surgery for bleeding, 22 patients developed postoperative low cardiac output, 19 patients developed respiratory failure, and 15 patients underwent peritoneal dialysis. Right ventricular outflow tract residual obstruction was observed in 19 patients and pulmonary regurgitation in 42 patients (mild pulmonary regurgitation in 32 patients and
Table I. Characteristics of Study Patients
Age (months) Age < 6 months Gender (male/female) Weight (kg) Hemoglobin (g/L) Prior aortopulmonary shunt surgery Arterial oxygen saturation (%) Arterial oxygen saturation < 60% Arrhythmia McGoon ratio Nakata index (mm2/m2) Aortic overriding degree (%) Size of VSD (mm) RVOT-PG max (mmHg) TEV/TAV < 1.0 Tricuspid regurgitation LVEDVI LVEF MEV/MAV < 1.0 (%) Associated malformations
Experimental group (n = 41)
Control group (n = 72)
P
14 ± 5 13 (31.7%) 29/12 8.8 ± 1.8 171.5 ± 31.3 5 (12.2%) 65.9 ± 8.8 30 (73.2%) 3 (7.3%) 1.57 ± 0.31 168 ± 36 48.6 ± 7.6 18.5 ± 4.8 95.4 ± 15.9 15 (36.6%) 29 (70.7%) 38.5 ± 6.4 61.2 ± 8.1 10 (24.4%) 12 (29.3%)
18 ± 6 7 (9.7%) 49/23 10.5 ± 2.6 162.3 ± 27.7 11 (15.3%) 73.3 ± 10.5 28 (38.9%) 4 (5.5%) 1.68 ± 0.36 172 ± 44 46.5 ± 7.7 17.9 ± 3.9 85.7 ± 13.3 18 (25.0%) 41 (56.9%) 40.1 ± 7.2 63.8 ± 9.6 10 (13.9%) 26 (36.1%)
0.0027 0.0047 0.8345 0.0003 0.1083 0.7825 0.0002 0.0008 0.7029 0.1038 0.6215 0.1642 0.3205 0.0007 0.2045 0.1636 0.2401 0.4045 0.2015 0.5370
Experimental group indicates right ventricular systolic dysfunction group; Control group, normal right ventricular systolic function group; VSD, ventricular septal defect; RVOT, right ventricular outflow tract; TEV/TAV, ratio between tricuspid peak early diastolic velocity and tricuspid peak late diastolic velocity; LVEDVI, left ventricular end-diastolic volume index; LVEF, left ventricular ejection fraction; and MEV/MAV, ratio between mitral peak early diastolic velocity and mitral peak late diastolic velocity. Table II. Intra-Operative Data Experimental group (n = 41) Transannular patch CPB time (minutes) ACC time (minutes) Lowest nasopharyngeal temperature (°C) Lowest rectal temperature (°C)
33 (80.5%) 98.4 ± 18.6 66.5 ± 14.1 25.4 ± 4.1 27.3 ± 3.9
CPB indicates cardiopulmonary bypass; and ACC, aortic cross clamping.
Control group (n = 72) 37 (51.4%) 92.5 ± 18.5 62.5 ± 14.6 25.8 ± 4.3 26.9 ± 4.1
P 0.0025 0.1066 0.1591 0.6297 0.6129
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moderate in 10 patients) by echocardiography before discharge. During follow-up after hospital discharge, 2 patients died (1 of infective endocarditis 39 months after surgery, the other of sudden death 41 months after surgery), and the remaining patients survived, with New York Heart Association class I (93 patients) and II (18 patients). Recurrent pleural effusion was observed in 7 patients, incomplete right bundle-branch block in 61 patients, right ventricular outflow tract residual obstruction in 35 patients, and pulmonary regurgitation in 62 patients (mild pulmonary regurgitation in 32, moderate in 10, and severe in 2) during follow-up. The postoperative data of the patients are shown in Table III. It can be observed that postoperative peritoneal dialysis, incomplete right bundle-branch block, age, pulmonary regurgitation, and RVOT residual obstruction at the last follow-up evaluation were 5 relative risk factors for late right ventricular systolic dysfunction after correction of TOF. Compared with the control group, the experimental group had a higher incidence of recurrent pleural effusion after correction of TOF. Logistic regression analysis: The variables with P < 0.10 obtained through univariate analysis were then entered into multivariate logistic regression analysis (right ventricular systolic dysfunction or not as independent variable, variables with P
