Indications and timing of pulmonary valve replacement after tetralogy of Fallot repair

Late pulmonary valve replacement in congenital heart disease patients without original congenital pulmonary valve pathology

Many congenital heart defects with pulmonary valve pathology are repaired or palliated in childhood. It is anticipated that these patients will need subsequent pulmonary valve replacement due to the pulmonary regurgitation or right ventricular dilation/failure that results from their original operation. Interestingly, some patients with prior congenital heart surgery and no congenital pulmonary valve pathology require pulmonary valve replacement in adulthood. The current study analyzed this subset of patients. The pediatric and adult congenital cardiac surgical databases at a large academic center were reviewed from 2001 to 2008 for pulmonary valve replacements. Patients without congenital pulmonary valve disease were identified. Preoperative, operative, and postoperative data were analyzed. Between 2001 and 2008, five patients with congenital heart disease but no pulmonary valve pathology underwent late pulmonary valve replacement. The initial congenital diagnoses were coarctation/ventricular septal defect (n = 3), complete atrioventricular septal defect (n = 1), and anomalous left coronary artery from the pulmonary artery (PA) (n = 1). All five patients had undergone main PA manipulation during their previous operations. Four of these patients had received PA banding and debanding, and one had received a Takeuchi tunnel repair and revision. All the patients underwent pulmonary valve replacement secondary to pulmonary regurgitation and right ventricular dilation. The average time from the last previous operation to the time of pulmonary valve replacement was 20.8 +/- 9.1 years. Bioprosthetic valves were used for all the pulmonary valve replacements, and there were no mortalities. Patients who have undergone previous PA manipulation, regardless whether congenital pulmonary pathology is present, may be at risk for pulmonary valve replacement in adulthood. This report describes five cases of patients with a history of congenital heart surgery but no congenital pulmonary valve pathology who required pulmonary valve replacement due to the consequences of prolonged pulmonary regurgitation. Although pulmonary regurgitation may be well tolerated for many years, it is further evidence for the importance of close follow-up assessment and monitoring of young adults with congenital heart disease.

Valvular and hemodynamic assessment with CMR

Cardiovascular magnetic resonance is able to provide a comprehensive assessment of valvular and hemodynamic function, including quantification of valve regurgitation and other flows, and accurate cardiac volumes and mass for assessing the effect on both ventricles. Combined with the ability to image all areas of the heart (including difficult areas, such as the right ventricle and pulmonary veins), it is an ideal technique for investigating patients who have heart failure in whom these areas need to be examined.

Effects of regional dysfunction and late gadolinium enhancement on global right ventricular function and exercise capacity in patients with repaired tetralogy of Fallot

BACKGROUND

The underlying mechanisms that contribute to global right ventricular (RV) dysfunction in patients with repaired tetralogy of Fallot are incompletely understood. We therefore sought to quantify regional RV abnormalities and to determine the relationship of these to global RV function and exercise capacity.

METHODS AND RESULTS

Clinical and cardiac magnetic resonance data from 62 consecutive patients with repaired tetralogy of Fallot were analyzed (median age at follow-up 23 years [limits 9 to 67 years]). Using cardiac magnetic resonance data, 3D RV endocardial surface models were reconstructed from segmented contours, and a correspondence between end diastole and end systole was computed with a novel algorithm. Regional RV abnormalities were quantified and expressed as segmental ejection fraction, spatial extent of dyskinetic area, displacement of dyskinetic area, and score of extent of late gadolinium enhancement. Regional abnormalities of function and hyperenhancement were greatest in the RV outflow tract (RVOT). These regional RVOT abnormalities correlated with global RV ejection fraction: RVOT ejection fraction r=0.64, P<0.0001; RVOT dyskinetic area r=-0.51, P<0.0001; RVOT displacement of dyskinetic area r=-0.49, P<0.0001; and RVOT late gadolinium enhancement score r=-0.33, P=0.01. Peak oxygen consumption during exercise correlated best with RVOT ejection fraction (r=0.56, P=0.0002) compared with the remainder of the RV (r=0.35, P=0.03). The only cardiac magnetic resonance variable independently predictive of aerobic capacity was RVOT ejection fraction (P=0.02).

CONCLUSIONS

A greater extent of regional abnormalities in the RVOT adversely affects global RV function and exercise capacity after tetralogy of Fallot repair. These regional measures may have important implications for patient management, including RVOT reconstruction, at the time of pulmonary valve replacement.

Pulmonary valve replacement in tetralogy of Fallot: impact on survival and ventricular tachycardia

BACKGROUND

Pulmonary valve replacement (PVR) in repaired tetralogy of Fallot (TOF) reduces pulmonary regurgitation and decreases right ventricular (RV) dilation, but its long-term impact on ventricular tachycardia (VT) and mortality is unknown. This study aimed to determine the incidence of death and VT in TOF after PVR and to test the hypothesis that PVR leads to improvement in these outcomes.

METHODS AND RESULTS

A total of 98 patients with TOF and late PVR for RV dilation were identified. Matched control subjects were identified for 77 of these patients; control subjects had TOF with RV dilation but no PVR. Matching was done by age (+/-2 years) and baseline QRS duration (+/-30 ms). No significant differences were found in age, QRS duration, type or decade of initial repair, age at TOF repair, or presence of pre-PVR VT between the 2 groups; limited echocardiographic and magnetic resonance imaging data showed no difference in left ventricular function but more RV dilation among PVR patients than control subjects. In the PVR group, 13 events occurred over 272 patient-years. No significant change in QRS duration was seen for any group. Overall 5- and 10-year freedom from death, VT, or both was 80% and 41%, respectively. In the matched comparison, no significant differences were seen in VT, death, or combined VT and/or death (P=0.32, P=0.06 [nearly favoring controls], and P=0.21).

CONCLUSIONS

This cohort experienced either VT or death every 20 patient-years. In a matched comparison with a similar TOF group, late PVR for symptomatic pulmonary regurgitation/RV dilation did not reduce the incidence of VT or death.

Percutaneous pulmonary valve implantation

Percutaneous pulmonary valve implantation is a new treatment option in patients with dysfunctional conduits. The aim of percutaneous pulmonary valve implantation is to prolong the lifespan of right ventricle to pulmonary artery conduits and thereby postponing open-heart surgery. Early results have shown a significant reduction in right ventricular pressure and right ventricular outflow tract gradient. During a follow-up of a median of 28 months, freedom from re-operation is 93 (2), 86 (3), 84 (4), and 70 (13)% at 10, 30, 50, and 70 months, respectively. The most common complication during follow-up are stent fractures with an incidence around 20%. Although clinically silent in the majority of cases, stent fractures led to re-intervention in the form of implantation of a second device (valve-in-valve). Valvar function during follow-up was well maintained. Significant pulmonary regurgitation was only seen in the context of endocarditis. Pulmonary valve implantation has the potential to become the standard procedure in the treatment of dysfunctional conduits. Bigger challenges will now have to be met in order to extend this technology to patients with native outflow tracts and free pulmonary regurgitation.

Transatrial-transpulmonary repair of tetralogy of Fallot

Routine early transatrial-transpulmonary repair of tetralogy of Fallot (TOF) has been performed at our institution since 1990. A transatrial-transpulmonary approach implies a minimal or no ventriculotomy and therefore it is expected to improve the right ventricular performance in the long term. Early transatrial-transpulmonary repair has been used for avoiding the deleterious effects of preoperative chronic cyanosis and spells, surgery for systemic-to-pulmonary artery shunts and their consequences, chronic right ventricular systolic pressure, and myocardial compensatory hypertrophy, with the aim of achieving better preservation of the right ventricular function in the long term. In our experience, transatrial-transpulmonary repair of TOF has been feasible at any age with immediate results that are comparable to those performed later in infancy.

Early primary repair of tetralogy of Fallot

Outcomes for surgical repair of tetralogy of Fallot with pulmonary stenosis are often considered to be a useful benchmark for the assessment of congenital surgical programs. This procedure, including preoperative assessment and postoperative management, falls in the middle of the spectrum of difficulty of all the congenital cardiac procedures. Within this anomaly itself, there is a wide spectrum of severity and difficulty. However, it is important to distinguish tetralogy with pulmonary stenosis or "simple tetralogy" from the much more complex anomaly tetralogy of Fallot with pulmonary atresia. Tetralogy of Fallot with pulmonary stenosis is virtually always operable. It is also a progressive condition that is therefore best repaired in early infancy following echocardiographic diagnosis alone.

Reproducibility of MRI measurements of right ventricular size and function in patients with normal and dilated ventricles

PURPOSE

To determine the inter- and intraobserver reproducibility of cardiac magnetic resonance (CMR)-derived measurements of right ventricular (RV) mass, volume, and function in patients with normal and dilated ventricles.

MATERIALS AND METHODS

CMR studies of 60 patients in three groups were studied: a normal RV group (N = 20) and two groups with RV dilation-atrial septal defect (ASD) (N = 20) and repaired tetralogy of Fallot (TOF) (N = 20). Two independent observers analyzed each study on two separate occasions. Inter- and intraobserver reproducibility of biventricular mass, volume, ejection fraction (EF), and stroke volume (SV) measurements were calculated.

RESULTS

High intraclass correlation coefficients (ICC) were found for interobserver (ICC = 0.94-0.99) and intraobserver (ICC = 0.96-0.99) comparisons of RV and left ventricular (LV) mass, volume, and SV measurements. RV and LV EF measurements were less reproducible (ICC = 0.79-0.87). RV mass measurements were significantly less correlated than the respective LV measurements. Small but statistically significant differences in correlation were noted in RV measurements across groups.

CONCLUSION

Except for RV mass, inter- and intraobserver reproducibility of RV size and function measurements is high and generally comparable to that in the LV in patients with both normal and dilated RV.

Potential strategies for myocardial regeneration in pediatric patients

Owing to the heart’s limited ability for self-repair, heart failure is a leading cause of death among all patient populations. Thus, a cell-based regenerative strategy for cardiac repair would be highly attractive. A variety of cell sources have been identified as candidates for myocardial repair, including skeletal myoblasts, various bone marrow stem cells, resident cardiac progenitors and embryonic stem cells. However, nearly all studies geared towards myocardial regeneration, both in animal models and in clinical trials, have focused on adult ischemic disease with regional muscle injury. Pediatric patients suffer from more diverse forms of heart disease, including congenital and acquired cardiomyopathies with global muscle dysfunction, as well as disorders of cardiac development, for example, left ventricular hypoplasia, atrial or ventricular septal defects. In this article, a broad range of cell-based therapies are discussed, emphasizing the rapidly evolving science surrounding these strategies and the outstanding questions before application to pediatric patients. It is probable that many of the cell types and delivery strategies capable of repairing adult myocardial diseases will require additional investigations to take advantage of the unique opportunities and challenges of pediatric patients.

Health care resource utilization in adults with congenital heart disease

The number of adults with congenital heart disease (CHD) is increasing. However, rates of health care resource utilization in this population are unknown. The objectives of this study were to describe the use of general health care resources in adults with CHD and to examine the impact of CHD severity on resource utilization. The study consisted of adults alive in 1996 who had > or = 1 diagnosis of a CHD lesion conforming to the International Classification of Disease, Ninth Revision, in the physician's claims database of the province of Quebec from 1983 to 2000. From 1996 to 2000, rates of health care utilization were measured. The impact of the severity of CHD on the use of health care resources was determined using multivariate models to adjust for age, gender, Charlson co-morbidity score, and duration of follow-up. The study population consisted of 22,096 adults with CHD (42% men). From 1996 to 2000, 87% received outpatient care from specialists, 68% visited emergency rooms, 51% were hospitalized, and 16% were admitted to critical care units. Patients with severe CHD had higher adjusted rates of outpatient cardiologist care (rate ratio [RR] 2.24, 95% confidence interval [CI] 2.06 to 2.45), emergency department utilization (RR 1.09, 95% CI 1.03 to 1.17), hospitalization (RR 1.30, 95% CI 1.19 to 1.43), and days in critical care (RR 2.12, 95% CI 1.80 to 2.50) than patients with other congenital cardiac lesions. Hospitalization rates were higher than in the general Quebec adult population (RR 2.08, 95% CI 2.00 to 2.17). In conclusion, adults with CHD have high rates of health care resource utilization, particularly those with severe lesions. Appropriate resource allocation is required to serve this growing population.

Management after childhood repair of tetralogy of fallot

The four characteristic findings in tetralogy of Fallot (TOF) include the following: 1) a malaligned ventricular septal defect; 2) right ventricular outflow and/or pulmonary valve/artery stenosis or atresia; 3) a dextraposed overriding aorta; and 4) right ventricular hypertrophy. This article focuses solely on the outcomes and treatment of surgically corrected patients born with TOF. In the modern era, early surgical repair consisting of ventricular septal defect closure and alleviation of right ventricular outflow obstruction have gained favor over early palliation with an aortopulmonary shunt followed by intracardiac repair. Surgical outcomes are excellent and dramatically improve prognosis. However, these patients are not "cured" and are at significant risk of developing subsequent electrical and hemodynamic problems. An operated patient with TOF should be evaluated at regular intervals by a cardiologist trained in congenital heart disease; any symptoms suggestive of hemodynamic or electrical compromise should spur further investigation. Advances in imaging, medical therapy, electrophysiology, device/resynchronization therapy, and percutaneous intervention provide the clinician with a number of therapeutic options. Surgical techniques have changed significantly since the early intracardiac repairs of the 1960s and 1970s. The deleterious hemodynamic and electrical effects of pulmonary regurgitation and ventriculotomy scars have spurred efforts to ensure pulmonary valvular competence and minimize the extent of ventricular incisions. Since Blalock and Taussig's first palliative shunt in 1945, the survival and quality of life for patients with TOF has improved dramatically; this is one of the great accomplishments for cardiovascular medicine in the 20th century. The 21st century promises further success with the advent of a myriad of technologic advancements.