ECHOCARDIOGRAPHY IN SURGICALLY REPAIRED TETRALOGY OF FALLOT
Long-Term Follow-Up in Repaired Tetralogy of Fallot: Can Deformation Imaging Help Identify Optimal Timing of Pulmonary Valve Replacement? Anna Sabate Rotes, MD, Crystal R. Bonnichsen, MD, Chelsea L. Reece, RDCS, Heidi M. Connolly, MD, Harold M. Burkhart, MD, Joseph A. Dearani, MD, and Benjamin W. Eidem, MD, Rochester, Minnesota
Background: Novel echocardiographic techniques based on myocardial deformation have not been extensively evaluated to assess right ventricular (RV) and left ventricular (LV) response after pulmonary valve replacement (PVR) in patients with repaired tetralogy of Fallot. Methods: Between 2003 and 2012, 133 patients undergoing first-time PVR after tetralogy of Fallot repair underwent echocardiographic assessment at Mayo Clinic. The last echocardiogram before PVR and 1 year after surgery were retrospectively analyzed with Velocity Vector Imaging. Results: Mean age at PVR was 35.5 6 16.2 years (54% women). Longitudinal peak systolic strain and strain rate before PVR were low: for the left ventricle, 14.8 6 3.5% and 0.8 6 0.2 sec1, and for the right ventricle, 16.2 6 4.1% and 0.9 6 0.3 sec1, respectively. There was no significant change in either parameter after surgery. A close correlation between LV and RV deformational parameters was found before PVR and was maintained after surgery. In the multivariate analysis, patients with better LV and RV peak systolic strain preoperatively were found to have better LV and RV peak systolic strain after surgery (P = .004 and P = .006, respectively). However, patients with the most improvement in deformation were those with worse RV function preoperatively (P = .002). Mean New York Heart Association class at early follow-up improved from 2.2 6 0.8 to 1.2 6 0.6 (P < .0001); RV peak systolic strain was the only factor associated with symptomatic improvement. Conclusion: LV and RV systolic and diastolic deformational parameters were decreased in patients with repaired tetralogy of Fallot undergoing PVR, and there was no significant change after surgery. However, preoperative systolic deformational parameters were predictive of postoperative ventricular function and New York Heart Association class after PVR and may be helpful to identify optimal timing for surgical intervention in this cohort. (J Am Soc Echocardiogr 2014;27:1305-10.) Keywords: Tetralogy of Fallot, Pulmonary valve replacement, Strain echocardiography, Magnetic resonance imaging
Tetralogy of Fallot (TOF) is the most common type of cyanotic congenital heart disease.1 Severe pulmonary regurgitation is common in patients with repaired TOF, often necessitating reconstruction of the From the Division of Pediatric Cardiology (A.S.R., B.W.E.), the Division of Cardiovascular Diseases (C.R.B., C.L.R., H.M.C., B.W.E.), and the Division of Cardiovascular Surgery (H.M.B., J.A.D.), Mayo Clinic, Rochester, Minnesota; noma de Barcelona, Barcelona, Spain (A.S.R.). and Universitat Auto This publication was made possible by CTSA Grant UL1 TR000135 from the National Center for Advancing Translational Sciences, a component of the National Institutes of Health. Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the National Institutes of Health. noma de Barcelona and is supported Dr Rotes is a PhD student at Universitat Auto La Caixa (Barcelona, Spain). by Fundacio Reprint requests: Benjamin W. Eidem, MD, Mayo Clinic, 200 First Street SW, Rochester, MN 55902 (E-mail: [email protected]). 0894-7317/$36.00 Copyright 2014 by the American Society of Echocardiography. http://dx.doi.org/10.1016/j.echo.2014.09.012
right ventricular (RV) outflow tract (RVOT) and pulmonary valve replacement (PVR). However, identifying the best timing for PVR continues to be challenging in clinical practice, because it may affect the recovery of RV function after surgery.2,3 The advent and use of new echocardiographic techniques based on myocardial deformation may help refine the decision-making process in these patients. These novel echocardiographic techniques have been used to assess RV and left ventricular (LV) dysfunction and ventricular interaction after TOF repair.4-8 If found to provide an accurate measure of ventricular function and functional class improvement after PVR, deformation imaging could be used as an alternative diagnostic tool in patients with repaired TOF, offering quantitative ventricular functional assessment to all patients irrespective of their clinical status or concomitant device status. However, there are few data and no consensus on the use of these new echocardiographic techniques to help determine the timing of operative intervention in patients with TOF. In addition, RV and LV response after PVR has not been extensively evaluated using these new techniques. 1305
1306 Sabate Rotes et al
Abbreviations
LV = Left ventricular MRI = Magnetic resonance imaging
NYHA = New York Heart Association PVR = Pulmonary valve replacement RV = Right ventricular RVOT = Right ventricular outflow tract SR = Strain rate TOF = Tetralogy of Fallot 2D = Two-dimensional
Journal of the American Society of Echocardiography December 2014
The primary aims of this study were (1) to evaluate whether patients with repaired TOF with good ventricular function before PVR had better ventricular function, functional class, and survival at early follow-up than patients with decreased ventricular function measured by novel deformational echocardiographic techniques and (2) to evaluate if the quantitative measures obtained with myocardial deformation are equivalent to ventricular functional assessment with cardiac magnetic resonance imaging (MRI) in this patient cohort.
METHODS Study Population We performed a retrospective review of all patients with repaired TOF who underwent first-time PVR at our institution between 2003 and 2012 (n = 146). To be included in this study, patients were required to have undergone at least one preoperative echocardiographic examination at our institution. Patients with associated pulmonary atresia, TOF with absent pulmonary valve, and/or concomitant atrioventricular canal defects were excluded. Patients who refused research authorization were also excluded. Overall, 133 of 146 patients (91%) met the inclusion criteria to be analyzed. The study was approved by the Mayo Clinic Institutional Review Board. Medical histories, as well as perioperative and follow-up data, were collected using all available records and postoperative surveys that are sent on a routine scheduled basis. In addition, the Social Security Death Index was reviewed. Echocardiography We selected the last echocardiogram before surgery and that closest to 1 year after surgery (range, 3.6 months to 2.7 years) for each patient. Strain Analysis. Digital echocardiographic images were transferred to a dedicated workstation for offline analysis. Images were analyzed with Velocity Vector Imaging software (Siemens Medical Solutions USA, Inc, Mountain View, CA). Images were analyzed only when overall quality was good and enabled visualization of the entire RV free wall. Mean frame rates on all views were between 38 and 41 Hz. Strain analysis was performed by a single observer blinded to the clinical data. The endocardium was manually traced, and the region of interest was manually adjusted to the wall thickness. Adequate tracking was visually assessed, and strain curves were accepted only if tracking appeared appropriate. The apical four-chamber view was used for the LV analysis (septum and free wall), and the RV free wall was used for the RV analysis. Two-Dimensional (2D) Echocardiography and Doppler Analysis. Categorical variables such as chamber size, ventricular function, and valve regurgitation were codified using a numeric scale
for analysis purposes: 1 = small, 0 = normal or none, 1 = borderline or trivial, 2 = mild, 3 = moderate, and 4 = severe. Intraobserver and Interobserver Reliability Analysis. Intraobserver and interobserver reliability analyses of LV and RV peak systolic longitudinal strain and strain rate (SR) and diastolic SR were performed in 10 random studies. Curves were traced anew, and strain curves generated anew, on the same cardiac cycle by the same observer and independently by a second observer for intraobserver and interobserver reliability, respectively. Absolute difference divided by the mean of the repeated observations and expressed as a percentage was used to measure variability. Outcomes Three different outcomes were chosen: (1) LV and RV peak systolic longitudinal strain at follow-up; (2) functional class at follow-up, defined in terms of the New York Heart Association (NYHA) classification; and (3) death of any cause. MRI Cardiac MRI before PVR was available for 49 patients. Correlations comparing MRI with strain imaging and to the traditional 2D echocardiography were performed. All MRI studies were performed on a 1.5-T system (Signa; GE Healthcare, Waukesha, WI) using an eight-element phased-array cardiac coil. After obtaining initial scout images, shortaxis cine balanced steady-state free precession images were obtained from the atrioventricular ring to the apex, and axial steady-state free precession images were obtained. The RV and LV volumes and ejection fraction were obtained by manual tracing of endocardial borders from the short-axis images at end-diastole and end-systole. Beginning in 2008, RV volumes and ejection fraction from the axial images were also routinely obtained. The following measurements were included: RV and LVend-diastolic volume indices, RV and LVend-systolic volume indices, and RV and LV ejection fractions. Statistical Analysis Descriptive statistics are reported as proportions for discrete data and as mean 6 SD for continuous data, except for variables that were not normally distributed, in which case medians and interquartile ranges are used, unless specified differently. Student t tests were used to compare continuous variables. Chi-square tests of independence were used to compare categorical variables, except for cells with percentage predicted
Long-Term Follow-Up in Repaired Tetralogy of Fallot: Can Deformation Imaging Help Identify Optimal Timing of Pulmonary Valve Replacement? Anna Sabate Rotes, MD, Crystal R. Bonnichsen, MD, Chelsea L. Reece, RDCS, Heidi M. Connolly, MD, Harold M. Burkhart, MD, Joseph A. Dearani, MD, and Benjamin W. Eidem, MD, Rochester, Minnesota
Background: Novel echocardiographic techniques based on myocardial deformation have not been extensively evaluated to assess right ventricular (RV) and left ventricular (LV) response after pulmonary valve replacement (PVR) in patients with repaired tetralogy of Fallot. Methods: Between 2003 and 2012, 133 patients undergoing first-time PVR after tetralogy of Fallot repair underwent echocardiographic assessment at Mayo Clinic. The last echocardiogram before PVR and 1 year after surgery were retrospectively analyzed with Velocity Vector Imaging. Results: Mean age at PVR was 35.5 6 16.2 years (54% women). Longitudinal peak systolic strain and strain rate before PVR were low: for the left ventricle, 14.8 6 3.5% and 0.8 6 0.2 sec1, and for the right ventricle, 16.2 6 4.1% and 0.9 6 0.3 sec1, respectively. There was no significant change in either parameter after surgery. A close correlation between LV and RV deformational parameters was found before PVR and was maintained after surgery. In the multivariate analysis, patients with better LV and RV peak systolic strain preoperatively were found to have better LV and RV peak systolic strain after surgery (P = .004 and P = .006, respectively). However, patients with the most improvement in deformation were those with worse RV function preoperatively (P = .002). Mean New York Heart Association class at early follow-up improved from 2.2 6 0.8 to 1.2 6 0.6 (P < .0001); RV peak systolic strain was the only factor associated with symptomatic improvement. Conclusion: LV and RV systolic and diastolic deformational parameters were decreased in patients with repaired tetralogy of Fallot undergoing PVR, and there was no significant change after surgery. However, preoperative systolic deformational parameters were predictive of postoperative ventricular function and New York Heart Association class after PVR and may be helpful to identify optimal timing for surgical intervention in this cohort. (J Am Soc Echocardiogr 2014;27:1305-10.) Keywords: Tetralogy of Fallot, Pulmonary valve replacement, Strain echocardiography, Magnetic resonance imaging
Tetralogy of Fallot (TOF) is the most common type of cyanotic congenital heart disease.1 Severe pulmonary regurgitation is common in patients with repaired TOF, often necessitating reconstruction of the From the Division of Pediatric Cardiology (A.S.R., B.W.E.), the Division of Cardiovascular Diseases (C.R.B., C.L.R., H.M.C., B.W.E.), and the Division of Cardiovascular Surgery (H.M.B., J.A.D.), Mayo Clinic, Rochester, Minnesota; noma de Barcelona, Barcelona, Spain (A.S.R.). and Universitat Auto This publication was made possible by CTSA Grant UL1 TR000135 from the National Center for Advancing Translational Sciences, a component of the National Institutes of Health. Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the National Institutes of Health. noma de Barcelona and is supported Dr Rotes is a PhD student at Universitat Auto La Caixa (Barcelona, Spain). by Fundacio Reprint requests: Benjamin W. Eidem, MD, Mayo Clinic, 200 First Street SW, Rochester, MN 55902 (E-mail: [email protected]). 0894-7317/$36.00 Copyright 2014 by the American Society of Echocardiography. http://dx.doi.org/10.1016/j.echo.2014.09.012
right ventricular (RV) outflow tract (RVOT) and pulmonary valve replacement (PVR). However, identifying the best timing for PVR continues to be challenging in clinical practice, because it may affect the recovery of RV function after surgery.2,3 The advent and use of new echocardiographic techniques based on myocardial deformation may help refine the decision-making process in these patients. These novel echocardiographic techniques have been used to assess RV and left ventricular (LV) dysfunction and ventricular interaction after TOF repair.4-8 If found to provide an accurate measure of ventricular function and functional class improvement after PVR, deformation imaging could be used as an alternative diagnostic tool in patients with repaired TOF, offering quantitative ventricular functional assessment to all patients irrespective of their clinical status or concomitant device status. However, there are few data and no consensus on the use of these new echocardiographic techniques to help determine the timing of operative intervention in patients with TOF. In addition, RV and LV response after PVR has not been extensively evaluated using these new techniques. 1305
1306 Sabate Rotes et al
Abbreviations
LV = Left ventricular MRI = Magnetic resonance imaging
NYHA = New York Heart Association PVR = Pulmonary valve replacement RV = Right ventricular RVOT = Right ventricular outflow tract SR = Strain rate TOF = Tetralogy of Fallot 2D = Two-dimensional
Journal of the American Society of Echocardiography December 2014
The primary aims of this study were (1) to evaluate whether patients with repaired TOF with good ventricular function before PVR had better ventricular function, functional class, and survival at early follow-up than patients with decreased ventricular function measured by novel deformational echocardiographic techniques and (2) to evaluate if the quantitative measures obtained with myocardial deformation are equivalent to ventricular functional assessment with cardiac magnetic resonance imaging (MRI) in this patient cohort.
METHODS Study Population We performed a retrospective review of all patients with repaired TOF who underwent first-time PVR at our institution between 2003 and 2012 (n = 146). To be included in this study, patients were required to have undergone at least one preoperative echocardiographic examination at our institution. Patients with associated pulmonary atresia, TOF with absent pulmonary valve, and/or concomitant atrioventricular canal defects were excluded. Patients who refused research authorization were also excluded. Overall, 133 of 146 patients (91%) met the inclusion criteria to be analyzed. The study was approved by the Mayo Clinic Institutional Review Board. Medical histories, as well as perioperative and follow-up data, were collected using all available records and postoperative surveys that are sent on a routine scheduled basis. In addition, the Social Security Death Index was reviewed. Echocardiography We selected the last echocardiogram before surgery and that closest to 1 year after surgery (range, 3.6 months to 2.7 years) for each patient. Strain Analysis. Digital echocardiographic images were transferred to a dedicated workstation for offline analysis. Images were analyzed with Velocity Vector Imaging software (Siemens Medical Solutions USA, Inc, Mountain View, CA). Images were analyzed only when overall quality was good and enabled visualization of the entire RV free wall. Mean frame rates on all views were between 38 and 41 Hz. Strain analysis was performed by a single observer blinded to the clinical data. The endocardium was manually traced, and the region of interest was manually adjusted to the wall thickness. Adequate tracking was visually assessed, and strain curves were accepted only if tracking appeared appropriate. The apical four-chamber view was used for the LV analysis (septum and free wall), and the RV free wall was used for the RV analysis. Two-Dimensional (2D) Echocardiography and Doppler Analysis. Categorical variables such as chamber size, ventricular function, and valve regurgitation were codified using a numeric scale
for analysis purposes: 1 = small, 0 = normal or none, 1 = borderline or trivial, 2 = mild, 3 = moderate, and 4 = severe. Intraobserver and Interobserver Reliability Analysis. Intraobserver and interobserver reliability analyses of LV and RV peak systolic longitudinal strain and strain rate (SR) and diastolic SR were performed in 10 random studies. Curves were traced anew, and strain curves generated anew, on the same cardiac cycle by the same observer and independently by a second observer for intraobserver and interobserver reliability, respectively. Absolute difference divided by the mean of the repeated observations and expressed as a percentage was used to measure variability. Outcomes Three different outcomes were chosen: (1) LV and RV peak systolic longitudinal strain at follow-up; (2) functional class at follow-up, defined in terms of the New York Heart Association (NYHA) classification; and (3) death of any cause. MRI Cardiac MRI before PVR was available for 49 patients. Correlations comparing MRI with strain imaging and to the traditional 2D echocardiography were performed. All MRI studies were performed on a 1.5-T system (Signa; GE Healthcare, Waukesha, WI) using an eight-element phased-array cardiac coil. After obtaining initial scout images, shortaxis cine balanced steady-state free precession images were obtained from the atrioventricular ring to the apex, and axial steady-state free precession images were obtained. The RV and LV volumes and ejection fraction were obtained by manual tracing of endocardial borders from the short-axis images at end-diastole and end-systole. Beginning in 2008, RV volumes and ejection fraction from the axial images were also routinely obtained. The following measurements were included: RV and LVend-diastolic volume indices, RV and LVend-systolic volume indices, and RV and LV ejection fractions. Statistical Analysis Descriptive statistics are reported as proportions for discrete data and as mean 6 SD for continuous data, except for variables that were not normally distributed, in which case medians and interquartile ranges are used, unless specified differently. Student t tests were used to compare continuous variables. Chi-square tests of independence were used to compare categorical variables, except for cells with percentage predicted
