Yang Min Kim

Outcomes of Pulmonary Valve Replacement in 170 Patients With Chronic Pulmonary Regurgitation After Relief of Right Ventricular Outflow Tract Obstruction: Implications for Optimal Timing of Pulmonary Valve Replacement

OBJECTIVES The objectives of this study were to evaluate outcomes of pulmonary valve replacement (PVR) in patients with chronic pulmonary regurgitation (PR) and to better define the optimal timing of PVR. BACKGROUND Although PVR is effective in reducing right ventricular (RV) volume overload in patients with chronic PR, the optimal timing of PVR is not well defined. METHODS A total of 170 patients who underwent PVR between January 1998 and March 2011 for chronic PR were retrospectively analyzed. To define the optimal timing of PVR, pre-operative and post-operative cardiac magnetic resonance imaging (MRI) data (n = 67) were analyzed. RESULTS The median age at the time of PVR was 16.7 years. Follow-up completeness was 95%, and the median follow-up duration was 5.9 years. Overall and event-free survival at 10 years was 98% and 70%, respectively. Post-operative MRI showed significant reduction in RV volumes and significant improvement in biventricular function. Receiver-operating characteristic curve analysis revealed a cutoff value of 168 ml/m(2) for non-normalization of RV end-diastolic volume index (EDVI) and 80 ml/m(2) for RV end-systolic volume index (ESVI). Cutoff values for optimal outcome (normalized RV volumes and function) were 163 ml/m(2) for RV EDVI and 80 ml/m(2) for RV ESVI. Higher pre-operative RV ESVI was identified as a sole independent risk factor for suboptimal outcome. CONCLUSIONS Midterm outcomes of PVR in patients with chronic PR were acceptable. PVR should be considered before RV EDVI exceeds 163 ml/m(2) or RV ESVI exceeds 80 ml/m(2), with more attention to RV ESVI.

Magnetic resonance imaging of complex congenital heart disease

Current MR techniques enable both anatomical and functional evaluations of the heart. Although it is rarely used as a primary diagnostic tool in pediatric cardiology, it can be used as a valuable adjunct to echocardiography and angiography. MRI is particularly useful in clarification of morphology of complex congenital heart diseases. It is the most accurate method of determination of visceral and atrial situs. It is easy to evaluate the systemic and pulmonary venous connections that are very important for the Fontan type of operation, especially in patients with visceral heterotaxy. It facilitates demonstration of diminutive pulmonary arteries in patients with pulmonary atresia. It clearly demonstrates juxtaposition of the atrial appendages that is often missed by echocardiography. The anatomy of the twisted atrioventricular connections is much more clear in MRI than in echocardiography. It enables en face imaging of ventricular septal defect that provides a surgical view. We find en face imaging particularly helpful in patients with double inlet left ventricle and transposition of the great arteries where the size of the ventricular septal defect governs the blood flow into the aorta. It is often advantageous to echocardiography in defining the type of univentricular atrioventricular connections by demonstrating the position and topology of the rudimentary chamber in difficult cases. In double outlet right ventricle, the spatial relationship of the ventricular septal defect to the great arterial valves can be clearly defined by visualizing the ventricular septal defect and the outlet septum in the same imaging plane.

Development of pulmonary arteriovenous fistulas after bidirectional cavopulmonary shunt

BACKGROUND A high incidence of pulmonary arteriovenous fistulas (PAVF) has been reported after bidirectional cavopulmonary shunt (BCPS) or total cavopulmonary shunt (TCPS; BCPS in patients with interrupted inferior vena cava). However, the definite diagnostic criteria or standard diagnostic modality of PAVF has not yet been defined. The goal of this study was to evaluate the diagnostic modalities and the prevalence of PAVF. METHODS We selected 10 patients with TCPS and 27 patients with BCPS. Lung perfusion scan, contrast echocardiogram, and pulmonary angiogram were performed. The results were compared among groups of patients and among each diagnostic modality. RESULTS All 10 patients with TCPS and 16 and 13 patients with BCPS showed positive results on contrast echocardiograms and lung scans, respectively. Six patients with TCPS and 4 patients with BCPS showed positive results on pulmonary angiograms. All patients with TCPS developed subclinical or clinical PAVF and 19 patients with BCPS developed subclinical PAVF and none of them had clinical PAVF during the short-term follow-up. CONCLUSIONS Most patients with bidirectional cavopulmonary anastomosis have subclinical evidence of right-to-left intrapulmonary shunting. This problem can be demonstrated with various diagnostic modalities.

Factors associated with right ventricular dilatation and dysfunction in patients with chronic pulmonary regurgitation after repair of tetralogy of Fallot: Analysis of magnetic resonance imaging data from 218 patients

OBJECTIVE The aim of the present study was to identify the factors associated with right ventricular (RV) dilatation and dysfunction in patients with chronic pulmonary regurgitation (PR) after repair of tetralogy of Fallot. METHODS From April 2002 to June 2013, 218 patients with repaired tetralogy of Fallot underwent magnetic resonance imaging; 165 (76%) underwent transannular repair and 36 (17%) underwent nontransannular repair. Linear regression analyses were used to identify the predictors for RV end-diastolic volume index (EDVI), end-systolic volume index (ESVI), and ejection fraction. RESULTS On univariable analysis, male sex, ventricular septal defect (VSD) closure through the right ventricle, larger pulmonary artery index, and greater PR fraction were associated with greater RV volume indexes. Multivariable analyses identified male sex (β = 17.55, P < .001 for RV EDVI; β = 14.08, P = .001 for RV ESVI), VSD closure through RV (β = 8.49, P = .048 for RV ESVI), longer interval since repair (β = 1.29, P = .014 for RV EDVI), and greater PR fraction (β = 1.92, P < .001 for RV EDVI; β = 1.38, P < .001 for RV ESVI) as independent predictors for greater RV volume indexes. On univariable analysis, male sex, VSD closure through the right ventricle, and greater PR fraction were associated with a lower RV ejection fraction. Multivariable analysis identified male sex (β = -3.10, P = .018), VSD closure through the right ventricle (β = -3.05, P = .020), and greater PR fraction (β = -0.27, P < .001) as independent predictors for a lower RV ejection fraction. CONCLUSIONS Male sex, VSD closure through the right ventricle, longer interval since repair, and greater PR fraction were independent predictors of RV dilatation after tetralogy of Fallot repair. Male sex, VSD closure through the right ventricle, and greater PR fraction were also independent predictors of RV dysfunction.

Three-dimensional computed tomography in children with compression of the central airways complicating congenital heart disease

PURPOSE We investigated the quality and usefulness of spiral computed tomography and three-dimensional reconstruction in children with obstruction of the central airways as a complication of congenital heart disease. MATERIALS AND METHODS Spiral computed tomography with three-dimensional reconstruction was performed in 49 children with obstruction of the central airways seen as a complication of congenital heart disease. Spiral scanning was performed during breathing in 40, and after sedation with chloral hydrate in 38. Contrast medium was administered through a pedal venous route in 42. We analyzed the motion artifact, additional information provided by, and clinical usefulness, of the three-dimensional images. We also investigated the factors influencing the quality of the images. RESULTS Stenoses were seen in the trachea in 21 patients, and in bronchuses in 28. Their causes were an anomaly of the aortic arch in 6, posterior displacement of the aortic arch in 7, posterior displacement of the ascending aorta in 5, compression of the brachiocephalic artery in 5, absent pulmonary valve syndrome in 6, displaced or dilated cardiovascular structure in 17, and pulmonary arterial sling in 2. Motion artifact caused mild or negligible degradation of images in all patients except 6. Breath-holding in non-sedated children produced more severe motion artifact than did cardiovascular pulsation. Three-dimensional images provided additional information over two-dimensional images in 11, and provided clinically useful information in 10. Contrast injection via the pedal route was better for the quality of three-dimensional images than brachiocephalic injection (p = 0.013). CONCLUSIONS Three-dimensional computed tomography is useful in evaluation of obstruction of the central airways in children with congenital heart disease. Despite the fact that motion artifact is unavoidable, the quality of three-dimensional images is acceptable for making a proper and accurate diagnosis. A pedal route is recommended for injection of contrast medium.

Bronchial compression by posteriorly displaced ascending aorta in patients with congenital heart disease

BACKGROUND We encountered several patients with posteriorly displaced ascending aorta and bronchial compression associated with congenital heart disease. We describe the helical computed tomography (CT) findings and explore the mechanism of airway compression. METHODS We retrospectively reviewed the clinical data and CT findings of 8 patients with posterior displacement of the ascending aorta. The bronchial stenosis was quantified on reformatted images perpendicular to the main-stem bronchi. On an axial image at the level of main bronchi, we measured depth of retrosternal space, interaortic distance, and aorto-spinal distance. To compare with control, we measured the same variables in 10 control patients. RESULTS In 7 patients, the main bronchus on the side of the aortic arch was squeezed between the ascending and descending aorta and showed slit-like stenosis. The right pulmonary artery was elongated around the ascending aorta in 5 patients and showed slit-like stenosis in 3. Patients with posterior displacement had significantly larger retrosternal space, smaller interaortic distance, and smaller aorto-spinal distance than did the control group. Aortopexy was undertaken in 3 patients. Follow-up computed tomograms of 2 patients showed improvement. CONCLUSIONS The posteriorly displaced ascending aorta may compress the main bronchus on the side of the aortic arch and right pulmonary artery against the descending aorta or spine. Even if the bronchial compression is mild with tolerable airway symptoms, these patients must be closely observed. When airway symptoms are severe, aortopexy should be considered.

Commissural malalignment of aortic-pulmonary sinus in complete transposition of great arteries

BACKGROUND Translocation of the coronary artery to the neoaorta is essential in the arterial switch operation. The goal of this study is to investigate (1) the frequency of commissural malalignment in complete transposition of the great arteries, (2) the usefulness of echocardiography in diagnosis of commissural malalignment, and (3) the impact of commissural malalignment on surgery. METHODS We retrospectively reviewed the medical records of 28 patients with complete transposition of the great arteries who underwent an arterial switch operation from February 2000 to August 2001. RESULTS Commissural malalignment was expected preoperatively in 11 patients by echocardiography and was confirmed in 13 patients intraoperatively. Four patterns of commissural malalignment were present: (1) sinus-facing of the pulmonary valve, (2) sinus-facing of the aortic valve, (3) sinus-facing of both valves, and (4) bicuspid pulmonary valve (functionally sinus-facing). Two patterns of severity were present: major and minor. To avoid torsion and stretching of the coronary arteries during surgery, various methods were needed: more extensive dissection of the coronary artery, trap door incision, supracommissural or juxtacommissural transfer, both coronary transfer to the same sinus, tube reconstruction of the coronary artery, and neoaorta dextrorotation anastomosis. One patient who had severe commissural malalignment died during the operation, and the cause of death was probably stretching or torsion of the coronary artery. CONCLUSIONS The recognition of malalignment of the facing sinus in transposition of the great arteries can be detected preoperatively by echocardiography. The surgical procedure of the arterial switch operation is influenced by the presence of commissural malalignment. Preoperative awareness of commissural malalignment seems to be helpful for surgeons to predict the need for an alternative operational procedure.

Truncus arteriosus with coarctation of persistent fifth aortic arch

Truncus arteriosus is a rare form of congenital heart defect. Among cases, 10% to 20% are associated with arch anomalies, such as interruption, coarctation, or patent ductus arteriosus. We treated a rare case of combined truncus with complex arch anomaly. The patient was a 2-month-old girl weighing 3.8 kg. Echocardiogram and computed tomogram showed interrupted aortic arch, truncus arteriosus, persistent fifth aortic arch, and its coarctation. One-stage total correction was performed under cardiopulmonary bypass without circulatory arrest. The operation consisted of a Rastelli procedure with a 12-mm valved conduit, coarctoplasty, and intraventricular baffling. The patient recovered well without complications.

Noninvasive imaging in congenital heart disease.

Imaging algorithms in congenital heart disease, as in the patient with acquired heart diseases continue to evolve, with more and more information gleaned noninvasively. The emphasis will be on the newer aspects of imaging, not cross sectional echocardiography with color Doppler.

Bicuspid pulmonary valve implantation using polytetrafluoroethylene membrane: early results and assessment of the valve function by magnetic resonance imaging

OBJECTIVES The durability of bioprosthetic valves in the pulmonary position is suboptimal. The objectives of this study were to evaluate the early results of polytetrafluoroethylene (PTFE) bicuspid pulmonary valve (PV) implantation and to better define the function of this valve by magnetic resonance imaging (MRI). METHODS Fifty-six patients who underwent PTFE bicuspid PV implantation between June 2009 and August 2011 were retrospectively analysed. The median age was 17.5 years and median valve size was 26 mm. Fundamental diagnoses were tetralogy of Fallot (n = 38), pulmonary atresia with ventricular septal defect (n = 8), double outlet right ventricle (n = 7) and absent PV syndrome (n = 3). Thirty-two patients with pulmonary regurgitation (PR) underwent MRI preoperatively and 22 of them underwent follow-up MRI at a median of 6.7 months postoperatively. RESULTS There was one early death. Postoperative echocardiography (n = 53) showed no or trivial PR in 49 patients and mild PR in 4. Median follow-up duration was 15.2 months. There was no late death or reoperation. Follow-up echocardiography (n = 41) performed at a median of 7.5 months postoperatively showed no or trivial PR in 33 patients and mild PR in 8 patients. Follow-up MRI showed a significant reduction in right ventricular volumes and improvement in biventricular function. The median PR fraction of this valve was 10%. CONCLUSIONS Early results of bicuspid PV implantation using PTFE membrane were satisfactory. PTFE bicuspid PV demonstrated excellent performance for the short term as evidenced by echocardiography and MRI. Long-term follow-up is mandatory to determine the durability of this valve.