Introduction
Pathophysiology of Repaired TOF
Pulmonary Regurgitation After TOF Repair
Effects of Chronic Volume Load on Ventricular Mechanics
RV Mechanics After TOF Repair
Structural Abnormalities | Functional Abnormalities |
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Inherent to TOF repair | RV volume overload |
Partial or complete removal of pulmonary valve tissue | Pulmonary regurgitation |
Infundibulotomy scar | Tricuspid regurgitation |
Resection of RV/infundibular muscle bundles | Left-to-right shunt |
Right atriotomy scar | Ventricular septal defect |
VSD patch | Atrial septal defect |
Residual or recurrent lesions | Aorto-pulmonary collaterals |
RV outflow tract obstruction | RV pressure overload |
Main or branch pulmonary artery stenosis | RV outflow or pulmonary artery stenosis |
Ventricular septal defect | Pulmonary vascular disease |
Atrial septal defect | Pulmonary venous hypertension secondary to LV dysfunction |
Acquired lesions | RV systolic dysfunction |
Tricuspid valve abnormalities | RV diastolic dysfunction |
RV outflow tract aneurysm | LV dysfunction |
RV fibrosis | Ventricular conduction delay |
Associated anomalies | Arrhythmias |
Dilated aorta | Atrial flutter |
Associated congenital cardiovascular anomalies | Atrial fibrillation |
Associated genetic and non-cardiac anomalies | Ventricular tachycardia |
Co-morbidities | |
Renal, pulmonary, musculoskeletal, neurodevelopmental abnormalities |
RV-LV Interaction After TOF Repair
Natural History And Outcomes After Tof Repair
Treatment Strategies Late After Tof Repair
Indications and Timing of Pulmonary Valve Replacement
Risks of Pulmonary Valve Replacement
Institution | Year | Number of Patients | Operative Death | Average Length of Follow-Up (years) | Late Death or transplant |
---|---|---|---|---|---|
SUNY, Syracuse [142] | 1985 | 11 | 0 | 1 | 0 |
Children's Memorial Hospital, Chicago [143] | 1997 | 49 | 1 | ||
University of Toronto [101] | 1997 | 85 | 1 | 5.8 | 3 |
Mayo Clinic [87] | 2001 | 42 | 1 | ||
Children's Hospital, Atlanta [144] | 2002 | 100 | 1 | 4.9 | 1 |
Leiden University, The Netherlands [97] | 2002 | 26 | 0 | 1.5 | 1 |
New England Med Center, Boston [105] | 2003 | 36 | 0 | 5 | 1 |
University of Zurich, Switzerland [100] | 2005 | 39 | 0 | 1.25 | 0 |
Multicenter, The Netherlands [145] | 2006 | 158 | 0 | 4.2 | 2 |
University of Toronto [99] | 2007 | 82 | 0 | 8.8 | 2 |
University Medical Center, Rotterdam [14] | 2008 | 17 | 0 | 6.4 | 0 |
International Society of Congenital Heart Disease [107] | 2008 | 93 | 0 | 3 | 2 |
Great Ormond Street, London[94] | 2008 | 71 | 0 | 1 | 0 |
Emory University [146] | 2009 | 107 | 3 | ||
Children's Hospital Boston [88] | 2009 | 77 | 0 | 2.8 | 6 |
Children's Hospital, Atlanta [147] | 2010 | 42 | 0 | 2.2 | 0 |
1035 | 0.68% | 2.2% |
Benefits of Pulmonary Valve Replacement
PR (%) | RVEDVi (ml/m2) | RVESVi (ml/m2) | RV EF (%) | LVEDVi (ml/m2) | LV EF (%) | QRS duration (ms) | Peak O2 consumption (ml/kg/min) | NYHA class | ||||||||||
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Before | After | Before | After | Before | After | Before | After | Before | After | Before | After | Before | After | Before | After | Before | After | |
Vliegen et al. [97] N = 26 Age: 29 ± 9 years | 46 ± 10 | 4 ± 8 | 167 ± 40 | 114 ± 35 | 99 ± 36 | 66 ± 35 | 42 ± 10 | 42 ± 11 | 86 ± 29 | 87 ± 17 | 2.0 ± 0.6 | 1.3 ± 0.5 | ||||||
Therrien et al. [15] N = 17 Age: 32 years | 163 ± 34 | 107 ± 26 | 109 ± 27 | 69 ± 22 | 32 ± 7 | 34 ± 10 | 2.0 ± 1.0 | 1.4 ± 0.5 | ||||||||||
van Straten et al. [148] N = 16 Age: 29 years | 48 ± 10 | 3 ± 5 | 164 ± 43 | 113 ± 26 | 94 ± 33 | 61 ± 18 | 44 ± 8 | 47 ± 12 | ||||||||||
Doughan et al. [84] N = 21 Age: 34 ± 9 years | 153 ± 34 | 142 ± 29 | ||||||||||||||||
Buechel et al. [16] N = 20 Age: 14 ± 3 years | 49 ± 14 | 9 ± 8 | 190 ± 33 | 109 ± 26 | 102 ± 27 | 58 ± 16 | 47 ± 7 | 45 ± 9 | 77 ± 10 | 84 ± 12 | 53 ± 6 | 56 ± 7 | 150 ± 18 | 148 ± 17 | ||||
Henkens et al. [98] N = 27 Age: 31 ± 8 years | 48 ± 11 | 166 | 100 | 98 | 58 | 42 ± 10 | 43 ± 10 | 89 ± 31 | 87 ± 18 | 56 ± 12 | 55 ± 9 | 2.0 ± 0.6 | 1.3 ± 0.3 | |||||
Oosterhof et al. [93] N = 71 Age: 29 years | 44 ± 13 | 5 ± 9 | 171 ± 44 | 119 ± 34 | 102 ± 38 | 70 ± 29 | 42 ± 10 | 43 ± 10 | 85 ± 22 | 94 ± 20 | 52 ± 9 | 53 ± 8 | 155 ± 29 | 144 ± 29 | 53% grade ≥II | 11% grade ≥II | ||
Gengsakul et al. [99] N = 82 Age: 28 ± 13 years | 164 ± 21 | 168 ± 21 | 54% grade ≥II | 13% grade ≥II | ||||||||||||||
Frigiola et al. [94] N = 71 Age 22 ± 11 years | 41 ± 9 | 5 ± 7 | 142 ± 43 | 91 ± 18 | 73 ± 33 | 43 ± 14 | 51 ± 10 | 54 ± 7 | 66 ± 12 | 73 ± 13 | 61 ± 8 | 64 ± 7 | 25 ± 10 | 25 ± 9 | 2.0 | 1.0 | ||
Geva et al. [95] N = 64 Age: 21 years | 49 ± 11 | 5 ± 9 | 201 ± 37 | 123 ± 25 | 107 ± 29 | 68 ± 24 | 47 ± 8 | 45 ± 9 | 89 ± 15 | 94 ± 17 | 58 ± 8 | 57 ± 7 | 154 (82-200) | 150 (80-202) | 26.5 (8-47) | 27 (10-48) | 47% grade ≥II | 8% grade ≥II |
Rationale and Timing of Pulmonary Valve Replacement
Indications for Pulmonary Valve Replacement
I. Asymptomatic patient with two or more of the following criteria
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○ RVOT obstruction with RV systolic pressure ≥2/3 systemic
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○ Severe branch pulmonary artery stenosis (<30% flow to affected lung) not amenable to transcatheter therapy
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○ ≥ Moderate tricuspid regurgitation
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○ Left-to-right shunt from residual atrial or ventricular septal defects with pulmonary-to-systemic flow ratio ≥ 1.5
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○ Severe aortic regurgitation
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○ Severe aortic dilatation (diameter ≥5 cm)
II. Symptomatic Patients
III. Special considerations
Role of CMR
Goals of CMR
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Quantitative assessment of left and right ventricular volumes, mass, stroke volumes, and ejection fraction.
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Evaluation of regional wall motion abnormalities.
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Imaging the anatomy of the right ventricular outflow tract, pulmonary arteries, aorta, and aorto-pulmonary collaterals.
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Quantification of PR, tricuspid regurgitation, cardiac output, and pulmonary-to-systemic flow ratio.
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Assessment of myocardial viability with particular attention to scar tissue in the ventricular myocardium aside from sites of previous surgery (e.g., ventricular septal defect and RVOT patches).
Study Protocol
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The importance of careful attention to details of patient preparation and placement in the scanner cannot be overemphasized. Optimal placement of ECG leads is paramount to quality gating. A peripheral intravenous cannula for injection of gadolinium-based contrast is placed in the following circumstances:1.First CMR examination2.>3 years since last late gadolinium enhancement (LGE) evaluation3.Deterioration in clinical status4.Regional or global ventricular function has worsened
Imaging protocol
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Localizing images: ECG-gated steady-state free precession (SSFP) localizing imaging in the axial, coronal, and sagittal planes followed by real-time interactive sequences for identification of key imaging planes and structures targeted for additional sequences (e.g., ventricular long- and short-axis planes, short-axis of the proximal MPA for subsequent measurements of PR).
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ECG-triggered, breath-hold cine SSFP in the following planes:
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▪ LV 2-chamber (Figure 9)
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▪ RV 2-chamber (Figure 10)
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▪ 4-chamber (4 slices) (Figure 11)
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▪ Ventricular short-axis (Figure 12). The latter is achieved by prescribing 12-14 equidistant slices (slice thickness 6-8 mm; inter-slice space 0-2 mm) covering the entire length of both ventricles. Particular attention is given to inclusion of the base of the RV and LV at end-diastole with addition of extra slices as needed for complete coverage.
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▪ Parallel to the left ventricular outflow (LV 3-chamber view).
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▪ Axial plane for imaging of the outflow tracts and branch pulmonary arteries (all first studies, optional thereafter).
××××× -
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Magnetic resonance angiogram (MRA): Non-gated, breath-hold gadolinium-enhanced (0.2 mmol/kg gadopentetate dimeglumine) 3-dimensional MRA (all first studies, optional thereafter) (Figure 14). Representative imaging parameters: echo time 1.5 ms; repetition time 4.5 ms; flip angle 40°; voxel size 0.95 × 1.06 × 2.4 mm reconstructed to 0.68 × 0.69 × 1.2 mm; number of acquisitions 2; SENSE acceleration factor 2; and acquisition time 20 s/acquisition.
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Flow measurements: ECG-triggered, breathe-through cine phase contrast flow measurements in the MPA (Figures 15, 16, 17, Additional file 3), aorta, and atrioventricular valves. Representative imaging parameters: echo time 3.7 ms; repetition time 5.9 ms; flip angle 15°; SENSE factor 2; field of view 300 mm; matrix 192 × 192; voxel size 1.56 × 1.56 × 6.0 mm reconstructed to 1.17 × 1.17 × 6.0 mm; 40 reconstructed images per cardiac cycle.
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Late gadolinium enhancement (LGE): ECG-triggered, breath-hold, phase sensitive LGE imaging performed 10-20 minutes after contrast administration in the following planes: ventricular short-axis (Figure 18), LV 2-chamber, LV 3-chamber, RV 2-chamber, and 4-chamber. Areas suspected of LGE (e.g., the thin walled RVOT free wall) are imaged in orthogonal planes and with phase direction swapped to facilitate recognition of artifacts.
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ECG-triggered, breath-hold cine SSFP in the short-axis of the aortic root and ascending aorta (in patients with dilated aortic root and ascending aorta).
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ECG-triggered, breath-hold turbo (fast) spin echo sequence with blood suppression for imaging of the outflow tracts and branch pulmonary arteries in patients with image artifacts from metallic implants.
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ECG-triggered, breathe-through cine phase contrast flow measurements in the branch pulmonary arteries (when branch pulmonary artery stenosis is identified).
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ECG-triggered, respiratory navigated, free breathing 3-dimensional isotropic SSFP for evaluation of the coronary arteries or as a substitute for contrast magnetic resonance angiography.
Report Template
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Anatomy of the RVOT and main and branch pulmonary arteries with emphasis on obstruction and/or dilatation or aneurysm formation.
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Biventricular size and function (global and regional).
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Vessel dimensions: aortic root, ascending aorta, MPA, right and left pulmonary arteries; if abnormal (e.g., tricuspid regurgitation), diameters of the atrioventricular valve.
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Flow measurements:
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▪ Ascending aorta, MPA, right and left pulmonary arteries
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▪ Pulmonary valve regurgitation
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▪ Other valve regurgitation
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Late gadolinium enhancement: presence, location, and extent.
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Associated anomalies: systemic and pulmonary veins, aortic arch sidedness and branching order.
Offline analysis
Reproducibility of CMR Measurements
CMR in Clinical Decision Making
Doppler Echocardiography | Cardiac CT | Nuclear Scintigraphy | Cardiac Catheterization | |
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All patients | • Predicted RV pressure by TR jet velocity • Valve function and interrogation of atrial and ventricular septa by color Doppler | |||
RV hypertension with RVOT obstruction or branch PA stenosis | Predicted RV pressure by TR jet velocity | Consider if (a) possible benefit from PA balloon dilation and/or stent; or (b) transcatheter PV implantation | ||
RV hypertension without RVOT obstruction or branch PA stenosis | Assessment of peripheral branch PA stenoses and pulmonary vascular resistance | |||
Branch PA stenosis without reliable pulmonary flow distribution by CMR | Lung perfusion scan | |||
Branch PA stenosis with ≤35% flow to one lung | Consideration of balloon dilation with or without stent placement | |||
Contraindications to CMR or large metallic artifacts | • Quantitative evaluation of RV size and function • Anatomy of RVOT and branch PAs | |||
Age >40 years | Coronary angiography before PVR | |||
Secundum ASD with systemic O2 saturation ≤92% | Hemodynamic assessment ± device closure |