Jae Gun Kwak

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.

Outcomes of biventricular repair for congenitally corrected transposition of the great arteries.

BACKGROUND This study was undertaken to evaluate long-term results of biventricular repairs for congenitally corrected transposition of the great arteries, and to analyze the risk factors that affect mortality and morbidity. METHODS Between 1983 and 2009, 167 patients with congenitally corrected transposition of the great arteries underwent biventricular repairs. The physiologic repairs were performed in 123 patients, and anatomic repairs in 44. Average follow-up was 9.3 +/- 6.6 years. RESULTS Kaplan-Meier estimated survival was 83.3% +/- 0.5% at 25 years in biventricular repair. In anatomic repair, left ventricular training and right ventricular dysfunction had negative impact on survival, but bidirectional cavopulmonary shunt had positive impact on survival. The reoperation-free ratio was 10.1% +/- 7.8% at 22 years after physiologic repair, and 46.2% +/- 12.4% at 15 years after anatomic repair (p = 0.885). Freedom from any arrhythmia was 49.6% +/- 7.5% at 22 years after physiologic repair, and 60.8% +/- 14.8% at 18 years after anatomic repair (p = 0.458). Freedom from systemic atrioventricular valve and ventricular dysfunction as well as tricuspid valve and right ventricular dysfunction was significantly higher in anatomic repair than in physiologic repair. CONCLUSIONS Long-term results of biventricular repair were satisfactory. Patients presenting with right ventricular dysfunction or need for left ventricular training represent a high-risk group of anatomic repair for which selection criteria are particularly important. Late functional outcomes of anatomic repair were excellent compared with physiologic repair. Anatomic repair is the procedure of choice for those patients if both ventricles are adequate or if surgical technique is modified with the help of additional a bidirectional cavopulmonary shunt.

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.

Permanent Epicardial Pacing in Pediatric Patients: 12-Year Experience at a Single Center

BACKGROUND Permanent cardiac pacing is not often done in children, and when done is usually accomplished through epicardial pacing. We reviewed a 12-year experience with the implantation of epicardial pacemakers by our clinical group. METHODS Fifty-three patients who underwent their first implantation of an epicardial pacemaker before the age of 18 years and between 1997 and 2009 were included in our study. The mean age of the patients at the time of first pacemaker implantation was 5.7±4.8 years. Indications for pacemaker implantation included postoperative or congenital atrioventricular block and sinus node dysfunction. The patients underwent 105 operations for the replacement of pacemaker pulse generators and 75 operations for the replacement of pacemaker leads. The most commonly used generator mode was the rate-responsive accelerometer-based (DDDR) mode, which was used in 40.9% of the patients. We used more non-steroid-eluting leads (70.1%) than steroid-eluting leads (29.1%). RESULTS The overall duration of follow-up in the study was 8.0±4.5 years (range, 2.1 months to approximately 17.0 years). Freedom from the need for generator replacement was 98.0%, 60.7%, and 11.1% at 1, 5, and 8 years, respectively. A tendency toward early generator exhaustion was observed among younger patients (p=0.058). The generator mode used for pacing did not significantly affect generator longevity. Freedom from the need for lead replacement was 98.3%, 83.8%, and 63.6% at 1, 5, and 10 years, respectively. The mean longevity of the leads used in the study was 10.8±0.8 years. Neither patient age at the time of lead implantation nor type of lead significantly affected lead longevity. CONCLUSIONS Lead longevity was sufficiently long and did not vary significantly according to type of lead. Generator longevity was not affected by lead type, generator mode, or patient age at the time of pacemaker implantation.

Long-term results after mitral valve repair in children

OBJECTIVE We analysed the long-term results of mitral valve (MV) repair in children. METHODS We reviewed clinical records of 139 children (<18 years) who underwent MV repair between 1988 and 2007. Patients with atrioventricular septal defect, single ventricle or atrioventricular discordance were excluded. Median age was 2.3 years (2 months to 17.6 years), and 47 children (34%) were infants. Mitral regurgitation (MR) was predominant in 125 patients (90%), and 91 (73%) of these showed MR grade > or = 3. Mitral stenosis (MS) was predominant in 14 patients (10%), and median mean pressure gradient across the MV was 9.0 mmHg (0-20 mmHg). Associated cardiac lesions were present in 111 patients (80%) and were addressed concurrently in 105 patients. Various surgical techniques were used according to the functional and pathologic findings of MV. RESULTS There was no early death. Median follow-up was 8 years (2 months to 20 years, 78% complete). Twenty-six patients required 29 MV re-operations, and 11 of these required MV replacements. At 15 years, freedom from MV re-operation and MV replacement was 77% and 90%, respectively. Diagnosis of MS and MV status on discharge (MR grade > or =3 or MS gradient > or =10 mmHg) were significant risk factors for re-operation. There were three late deaths, and the overall survival was 97% at 15 years. Among 122 survivors with MR, 102 patients (84%) underwent echocardiography during follow-up. The degree of MR decreased significantly and only five patients showed MR grade 3. Among 14 survivors with MS, eight patients (57%) underwent echocardiography during follow-up. The degree of MS decreased significantly and median MS gradient was 2.8 mmHg (0-10 mmHg). All survivors remain in the NYHA class I or II. CONCLUSIONS MV repair in children showed excellent survival, acceptable re-operation rate and satisfactory valve function at long-term follow-up. Residual MV dysfunction was a significant risk factor for re-operation, but re-repair was successful in more than half of the patients who underwent re-operation.

Surgical pulmonary valve insertion--when, how, and why.

Relief of right ventricular outflow tract obstruction in tetralogy of Fallot or similar physiology often results in pulmonary regurgitation. The resultant chronic volume overload can lead to right ventricular dilatation, biventricular dysfunction, heart failure symptoms, arrhythmias, and sudden death. Although pulmonary valve replacement can lead to improvement in functional class and a substantial decrease or normalisation of right ventricular volumes, the optimal timing of pulmonary valve replacement is not well defined. Benefits of pulmonary valve replacement have to be weighed against the risks of this procedure, including subsequent reoperation. This article will review the benefits and risks of pulmonary valve replacement, options for pulmonary valve substitute, and timing of pulmonary valve replacement in patients with chronic pulmonary regurgitation after relief of right ventricular outflow tract obstruction.

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.

Surgical Management of Pulmonary Atresia With Ventricular Septal Defect: Early Total Correction Versus Shunt

BACKGROUND We changed our surgical strategy for pulmonary atresia with ventricular septal defect from shunt operation to early total correction as an initial procedure since 2004. The objective of this study was to compare the surgical outcomes of shunt and early total correction. METHODS From 1997 to 2008, 47 patients with pulmonary atresia with ventricular septal defect and no major aortopulmonary collateral arteries who underwent surgical correction were enrolled in this retrospective study. Twenty-nine patients underwent palliative shunt operation (group S) and 18 patients underwent early total correction (group T). The patients in group T were younger than that of group S (23.2±12.6 vs 40.1±23.3 days; p=0.008). RESULTS There were 3 operative mortalities in group S and 1 operative mortality in group T. Four interstage deaths in group S and 1 late death in group T occurred. There was no difference in the overall survival rate between the 2 groups (p=0.3). The reoperation rate was higher in group S (p<0.0001) and the reintervention rate was higher in group T (p=0.006). The ventilator support time (5.5±5.1 vs 4.2±5.6 days; p=0.016) and intensive care unit stay (20.3±25.5 vs 15.5±16.0 days; p=0.233) were longer in group T. The preoperative age, body weight, and pulmonary artery size were not associated with the prolonged ventilator support time in group T. The patients who had received preoperative ventilator care showed tendency of prolonged postoperative ventilator support time (p=0.004). CONCLUSIONS The midterm results of early total correction for pulmonary atresia with ventricular septal defect are acceptable. Despite a difficult postoperative course, there was no difference in the mortality compared with shunt operation. Although the reintervention rate was higher in the early total correction group, we were able to avoid interstage mortalities that occurred in the shunt group, and we reduced the reoperation rate in the early total correction group.

Mid-term Results of the Hancock II Valve and Carpentier-Edward Perimount Valve in the Pulmonary Portion in Congenital Heart Disease

BACKGROUND As the number of cases with artificial pulmonary valve implantation increases for congenital heart disease, the number of young adults with artificial pulmonary valves has also increased. METHODS From 2000 to 2007, 146 artificial valves, such as the Carpentier-Edward Perimount, Hancock II, Biocor, homograft and hand-made valves were implanted for pulmonary valve in 132 patients with various forms of congenital heart disease. Among them, the outcomes of the Carpentier-Edward Perimount (n=63) and the Hancock II (n=40) valves were reviewed retrospectively. The mean age at initial implantation was 12.8+/-6.6 years. The overall duration of follow up was 36.0+/-24.2 months. RESULTS There was an early death due to right ventricular failure with intractable ventricular arrhythmia and 3 late deaths due to progressive right ventricular failure, dilated cardiomyopathy and infective endocarditis. The overall survival and re-operation free rate was 96.3% and 89.8% respectively. Eight out of 63 Carpentier-Edward patients (12.6%) underwent re-replacement at 49.2+/-25.2 months. The re-operation free rates were 97.7%, 87.7% and 50% at 1, 3 and 5 years respectively. There was no re-operation required for the 40 Hancock II patients over 18.0+/-10.8 months. There was no statistical significance in the re-operation free rates between these 2 valves (p-value=0.51). CONCLUSIONS The overall survival rate associated with pulmonary valve bioprosthetic valve implantation was acceptable. However, the re-operation freedom rate was not satisfactory at mid-term for the Carpentier-Edward.

Early Surgical Correction of Atrioventricular Valvular Regurgitation in Single-Ventricle Patients

BACKGROUND The purpose of this study is to evaluate the effectiveness of early surgical correction for atrioventricular valve regurgitation (AVVR) in single-ventricle patients. METHODS The medical records of 39 single-ventricle patients who underwent atrioventricular surgery more than once between 1996 and 2008 were reviewed. RESULTS The mean preoperative grade of AVVR was 2.6 ± 0.7. Four patients underwent valvular operations at first palliative surgery, 3 patients before bidirectional cavopulmonary connection, 13 at bidirectional cavopulmonary connection, 6 in the interstage between bidirectional cavopulmonary connection and Fontan, 10 at Fontan, and 3 after Fontan procedure. Surgical techniques for valve were edge-to-edge sutures for bridging leaflets, leaflet cleft repair, partial or complete annuloplasty with strip, or artificial valve implantation. Although there was no statistical significance, the patients who underwent early operation (AVVR grade less than 2) showed a tendency toward better atrioventricular valvular function during the postoperative follow-up (57.1 months, range: 2 ∼ 129 months). None of the patients whose preoperative AVVR grade less than 2 showed an AVVR more than 2 at the final echocardiography. There were 4 deaths overall due to sepsis, Fontan failure, and sudden cardiac arrest. Final echocardiographic findings showed a mean AVVR of 1.6 ± 0.8 and acceptable cardiac function. All living patients were in a good New York Heart Association functional class (1.07 ± 0.2). CONCLUSIONS Even though we could not find statistically significant evidence of benefit for early correction of AVVR in single-ventricle patients, the patients undergoing early valvular operation for regurgitation showed a tendency toward better atrioventricular valvular function at midterm.