Relation between age at surgery and regression of right ventricular hypertrophy in tetralogy of Fallot

Design and rationale of a clinical trial to increase cardiomyocyte division in infants with tetralogy of Fallot

BACKGROUND

Patients with Tetralogy of Fallot with pulmonary stenosis (ToF/PS), the most common form of cyanotic congenital heart disease (CHD), develop adverse right ventricular (RV) remodeling, leading to late heart failure and arrhythmia. We recently demonstrated that overactive β-adrenergic receptor signaling inhibits cardiomyocyte division in ToF/PS infants, providing a conceptual basis for the hypothesis that treatment with the β-adrenergic receptor blocker, propranolol, early in life would increase cardiomyocyte division. No data are available in ToF/PS infants on the efficacy of propranolol as a possible novel therapeutic option to increase cardiomyocyte division and potentially reduce adverse RV remodeling.

METHODS

Using a randomized, double-blind, placebo-controlled trial, we will evaluate the effect of propranolol administration on reactivating cardiomyocyte proliferation to prevent adverse RV remodeling in 40 infants with ToF/PS. Propranolol administration (1 mg/kg po QID) will begin at 1 month of age and last until surgical repair. The primary endpoint is cardiomyocyte division, quantified after ¹⁵N-thymidine administration with Multi-isotope Imaging Mass Spectrometry (MIMS) analysis of resected myocardial specimens. The secondary endpoints are changes in RV myocardial and cardiomyocyte hypertrophy.

CONCLUSION

This trial will be the first study in humans to assess whether cardiomyocyte proliferation can be pharmacologically increased. If successful, the results could introduce a paradigm shift in the management of patients with ToF/PS from a purely surgical approach, to synergistic medical and surgical management. It will provide the basis for future multi-center randomized controlled trials of propranolol administration in infants with ToF/PS and other types of CHD with RV hypertension.

CLINICAL TRIAL REGISTRATION

The trial protocol was registered at clinicaltrials.gov (NCT04713657).

Long-term follow-up after transatrial-transpulmonary repair of tetralogy of Fallot: influence of timing on outcome

OBJECTIVES

Our goal was to report the long-term serial follow-up after transatrial–transpulmonary repair of tetralogy of Fallot (TOF) and to describe the influence of the timing of the repair on outcome.

METHODS

We included all patients with TOF who had undergone transatrial–transpulmonary repair between 1970 and 2012. Records were reviewed for patient demographics, operative details and events during the follow-up period (death, pulmonary valve replacement, cardiac reinterventions and hospitalization/intervention for arrhythmias). In patients with elective early primary repair of TOF after 1990, a subanalysis of the optimal timing of TOF repair was performed.

RESULTS

A total of 453 patients were included (63% male patients; 65% had transannular patch); 261 patients underwent primary elective repair after 1990. The median age at TOF repair was 0.7 years (25th–75th percentile 0.3–1.3) and decreased from 1.7 to 0.4 years from before 1990 to after 2000, respectively (P < 0.001). The median follow-up duration after TOF repair was 16.8 years (9.6–24.7). Events developed in 182 (40%) patients. In multivariable analysis, early repair of TOF (<6 months) [hazard ratio (HR) 3.06; P < 0.001] and complications after TOF repair (HR 2.18; P = 0.006) were found to be predictive for an event. In a subanalysis of the primary repair of TOF after 1990, the patients (n = 125) with elective early repair (<6 months) experienced significantly worse event-free survival compared to patients who had elective repair later (n = 136). In multivariable analysis, early repair (HR 3.00; P = 0.001) and postoperative complications (HR 2.12; P = 0.010) were associated with events in electively repaired patients with TOF.

CONCLUSIONS

Transatrial–transpulmonary repair of TOF before the age of 6 months may be associated with more events during the long-term follow-up period.

Ruptured Sinus of Valsalva Aneurysm: Use of Multimodality Imaging in Delineating Structure and Function

Sinus of Valsalva aneurysm is a rare defect that can present with fatal complications in case of rupture. Heart failure symptoms are common due to high fraction of the resultant shunt. Multimodality imaging and invasive hemodynamic assessment is essential for comprehensive evaluation of the defect and guiding surgical planning. We describe the case of a 40-year-old woman who presented with heart failure symptoms and was found to have ruptured sinus of Valsalva aneurysm on transthoracic echocardiogram. Cardiac computed tomography angiography further characterized the defect and the associated anomalies. Right heart catheterization assessed the hemodynamic significance of the left to right shunt. Intraoperative findings highlighted the associated congenital anomalies including supracristal ventricular septal defect. The use of intraoperative transesophageal echocardiography proved essential in detecting worsening of the right ventricular outflow track infundibular dynamic obstruction post repair thus delineating the importance of maintaining adequate cardiac preload. This case highlights a stepwise approach in the anatomical characterization of sinus of Valsalva aneurysm using multimodality imaging and the use of hemodynamic assessment and intraoperative imaging to guide surgical planning.

Tetralogy of Fallot Will be Treated Interventionally Within Two Decades

Tetralogy of Fallot is considered a prototype congenital heart disease because of its embryological, anatomical, pathophysiological, and management aspects. Current management usually relies on a complete surgical repair that is electively performed between 3 and 6 months of age. With the advances of interventional cardiology especially in the fields of ventricular septal defect closure, stent, and pulmonary valve replacement, the question of complete repair of tetralogy of Fallot by interventional means can be discussed. Tetralogy of Fallot is a complex disease with multiple lesions, all individually amenable to transcatheter treatment. In this article, we will review current status of various aspects of tetralogy of Fallot focusing on interventional aspects, giving insights of what would be the ideal platform of a fully interventional repair.

Primary surgical repair of tetralogy of Fallot at under three months of age

Background Classical management of small infants with tetralogy of Fallot has involved placement of a Blalock-Taussig shunt followed later by complete repair, rather than primary complete repair which is the strategy adopted in larger infants. Some advantages of early complete repair compared to a staged strategy have been shown. We sought to review our institutional outcomes. Methods Patients under 3-months old undergoing complete surgical repair of tetralogy of Fallot in our institution between 2005 and 2015 were retrospectively reviewed and compared with an older control group matched by anatomical diagnosis and outflow tract intervention. Results Fourteen index cases (group A) and 14 controls (group B) were identified. At surgery, the median age was 43 days and weight 4.2 kg in group A, and 130 days and 6.1 kg in group B. Nine of 14 in group A were admitted for surgery as emergencies compared to none in group B. Peak inotrope score (22.3 vs. 12.8, p = 0.02) and intensive care unit stay (4.4 vs. 2.6 days, p = 0.02) were higher in group A. Bypass and crossclamp times, duration of intubation, and total length of stay did not differ. Conclusions We conclude that although babies undergoing early repair of tetralogy of Fallot have an increased need for intensive care support in the early postoperative period, the total length of stay is not prolonged despite more emergency admissions. As it is known that early repair may reduce long-term morbidity, we propose consideration of earlier complete repair of tetralogy of Fallot.

Repair of Tetralogy of Fallot in Infancy via the Atrioventricular Approach

Background

Tetralogy of Fallot (TOF) is a well-recognized congenital heart disease. Despite improvements in the outcomes of surgical repair, the optimal timing of surgery and type of surgical management of patients with TOF remains controversial. The purpose of this study was to assess outcomes following the repair of TOF in infants depending on the surgical procedure used.

Methods

This study involved the retrospective review of 120 patients who underwent TOF repair between 2010 and 2013. Patients were divided into three groups depending on the surgical procedure that they underwent. Corrective surgery was done via the transventricular approach (n=40), the transatrial approach (n=40), or a combined atrioventricular approach (n=40). Demographic data and the outcomes of the surgical procedures were compared among the groups.

Results

In the atrioventricular group, the incidence of the following complications was found to be significantly lower than in the other groups: complete heart block (p=0.034), right ventricular failure (p=0.027) and mediastinal bleeding (p=0.007). Patients in the atrioventricular group had a better postoperative right ventricular ejection fraction (p=0.001). No statistically significant differences were observed among the three surgical groups in the occurrence of tachycardia, renal failure, and tricuspid incompetence. The one-year survival rates in the three groups were 95%, 90%, and 97.5%, respectively (p=0.395).

Conclusion

Combined atrioventricular repair of TOF in infancy can be safely performed, with acceptable surgical risk, a low incidence of reoperation, good ventricular function outcomes, and an excellent survival rate.

Early and late outcomes of total repair of tetralogy of Fallot: risk factors for late right ventricular dilatation

OBJECTIVES

This study was undertaken to assess the early and long-term results of total repair of tetralogy of Fallot (TOF) and to identify the risk factors associated with late right ventricular (RV) dilatation.

METHODS

The medical records of 326 patients (male:female = 192:134) who underwent total repair of TOF at Pusan National and Dong-A University Hospitals between July 1991 and May 2011 were retrospectively reviewed. Median age and weight at the time of operation were 13.0 months and 8.7 kg, respectively. Right ventricular end-diastolic dimensions and left ventricular end-diastolic dimensions were obtained during follow-up echocardiography to identify the risk factors associated with late RV dilatation.

RESULTS

There were one operative death (0.3%) and 8 late deaths (2.5%). Of late deaths, two were related to operation-related cardiac problems. Overall survival rates at 5, 10, and 15 years were 97.0%, 95.4%, and 95.4%, and the corresponding freedom from cardiac death were 98.8%, 98.8%, and 98.8%, respectively. Freedom from re-operation and re-intervention were 84.4%, 74.2% and 74.2%. Six patients underwent pulmonary valve replacement during the follow-up period. Transannular patch (P = 0.036) and postoperative ventilator support period (P < 0.001) were found to be significant risk factors of late RV dilatation in multivariate analysis.

CONCLUSIONS

Total correction of TOF can be performed with a very low mortality rate. However, the postoperative re-operation or re-intervention rates remain relatively high. Late RV dilatation after total repair of TOF was found to be associated with transannular patch enlargement and a longer postoperative ventilator support period.

Primary early correction of tetralogy of Fallot irrespective of age

OBJECTIVE

The policy of early repair of patients with tetralogy of Fallot, irrespective of age, as opposed to initial palliation with a shunt, remains controversial. The aim of our study was to analyze the midterm outcome of primary early correction of tetralogy of Fallot.

METHODS

Between 1996 and 2005, a total of 61 consecutive patients less than 6 months of age underwent primary correction of tetralogy of Fallot in two institutions. The median age at surgery was 3.3 months, and 27 patients (44%) were younger than 3 months of age, including 12 (20%) newborns. We analyzed the patients in 2 groups: those younger than 3 months of age, and those aged between 3 and 6 months.

RESULTS

There was one early (1.6%), and one late death. Actuarial survival was 98.4%, 96.7%, 96.7% at 1, 5, and 10 years respectively, with a median follow up of 4.5 years. There was no difference in survival, bypass time, lengths of ventilation, and hospital stay between the groups. A transjunctional patch was placed significantly more often in the patients younger than 3 months (p = 0.039), with no adverse effect on survival and morbidity during the follow-up. Freedom from reoperation was 98.2%, 92.2%, and 83% at 1, 5, and 10 years respectively, with no difference between the groups.

CONCLUSION

Elective primary repair of tetralogy of Fallot in asymptomatic patients is delayed beyond 3 months of age. In symptomatic patients, primary repair of tetralogy of Fallot is performed irrespective of age, weight and preoperative state. This approach is safe, and provides an excellent midterm outcome with acceptable morbidity and rates of reintervention. The long-term benefits of this approach must be established by careful follow-up, with particular emphasis on arrhythmias, right ventricular function, and exercise performance.

Surgery Insight: late complications following repair of tetralogy of Fallot and related surgical strategies for management

Biventricular correction of tetralogy of Fallot was devised more than 50 years ago. Current short-term outcomes are excellent. The potential for late complications is, however, an important concern for the growing number of postrepair survivors. Progressive pulmonary valve regurgitation leading to right heart failure and arrhythmia are centrally important problems faced by these patients. New techniques are, however, likely to change the future outcomes for postrepair survivors. These techniques include percutaneous valve replacement, arrhythmia ablation surgery, and strategies that emphasize preservation of the pulmonary valve even at the cost of leaving some residual valvular stenosis. The objectives of this Review are to outline the major complications that arise late after repair of tetralogy of Fallot, to describe the surgical approaches that have been developed to avoid and manage arising complications, and to briefly explore how novel treatment paradigms could change the future long-term outlook for patients following tetralogy repair.

Tetralogy of Fallot: Late outcome after repair and surgical implications

Cardiac surgery has transformed the outcome for patients with tetralogy of Fallot. Repair has conveyed excellent long-term results with most patients remaining well and leading normal lives. However, there are problems with late morbidity and mortality primarily due to right ventricular dysfunction, exercise intolerance, arrythmia, and sudden cardiac death. There has been a dynamic shift in our surgical approach to managing patients with tetralogy over the past 5 decades. This in part accounts for persisting difficulties in predicting late outcome for evry single patient with repaired tetralogy of Fallot. There are, however, several confounding variables, influencing long-term outcome for these patients, namely the underlying anatomical substrate, age at repair, surgical approach to repair, and residual hemodynamic abnormalities. It is gratifying to see that recent knowledge accumulated from long-term follow-up studies is influencing contemporary surgical practice. Individualized strategies aiming to minimize the potential for free pulmonary regurgitation, and the long-term detrimental effects associated with it, need to continue to develop. Preservation of right ventricular and pulmonary valve function combined with early restoration of normal pulmonary blood flow are likely to convey an even better long-term outlook for these patients. Further follow-up studies with assessment of bi-venticular function, however, are needed in both our older and contemporary cohorts with repaired tetralogy of Fallot. Copyright 2000 by W.B. Saunders Company

Complete repair of tetralogy of Fallot in the neonate: results in the modern era

OBJECTIVE

To review more than a decade of experience with complete repair of tetralogy of Fallot (TOF) in neonates at the University of Michigan; to assess early and late survival, perioperative complications, and the incidence of reoperation; and to analyze patient, procedural, and morphologic risk factors to determine their effects on outcome.

SUMMARY BACKGROUND DATA

Palliation of TOF with systemic-to-pulmonary artery shunts has been the accepted standard for symptomatic neonates and infants. Complete repair has traditionally been reserved for infants older than 6 months of age because of the perception that younger and smaller infants face an unacceptably high surgical risk.

RESULTS

A retrospective review from August 1988 to November 1999 consisted of 61 consecutive symptomatic neonates with TOF who underwent complete repair. Thirty-one patients had TOF with pulmonary stenosis, 24 had TOF with pulmonary atresia, and 6 had TOF with nonconfluent pulmonary arteries. The mean age at repair was 16 +/- 13 days, and the mean weight was 3.2 +/- 0.7 kg. Before surgery, 36 patients were receiving an infusion of prostaglandin, 26 were mechanically ventilated, and 11 required inotropic support. Right ventricular outflow tract obstruction was managed with a transannular patch in 49 patients and a right ventricle-to-pulmonary artery conduit in 12. Cardiopulmonary bypass time averaged 71 +/- 26 minutes. Hypothermic circulatory arrest was used in 52 patients (mean 38 +/- 12 minutes). After cardiopulmonary bypass, the average intraoperative right/left ventricular pressure ratio was 55% +/- 13%. There were no new clinically apparent neurologic sequelae after repair. The postoperative intensive care unit stay was 9.1 +/- 8 days, with 6.8 +/- 7 days of mechanical ventilation. There was one hospital death from postoperative necrotizing enterocolitis on postoperative day 71 and four late deaths, only one of which was cardiac-related. Actuarial survival was 93% at 5 years. Follow-up was available for all 60 hospital survivors and averaged 62 months (range 1-141 months). Twenty-two patients required a total of 24 reoperations at an average interval of 26 months after repair. Indications for reoperation included right ventricular outflow tract obstruction (19), branch pulmonary artery stenosis (11), severe pulmonary insufficiency (4), and residual ventricular septal defect (1). The 1-month, 1-year, and 5-year freedom from reoperation rates were 100%, 89%, and 58%, respectively.

CONCLUSIONS

Complete repair of TOF in the neonate is associated with excellent intermediate-term survival. Although the reoperation rate is significant, this is to be expected with the complex right ventricular outflow tract and pulmonary artery anatomy seen in symptomatic neonates and the need for conduit replacement in patients with TOF with pulmonary atresia.

Complete reversal of fatal pulmonary hypertension in rats by a serine elastase inhibitor

Progression of pulmonary hypertension is associated with increased serine elastase activity and the proteinase-dependent deposition of the extracellular matrix smooth muscle cell survival factor tenascin-C (refs. 1,2). Tenascin-C amplifies the response of smooth muscle cells to growth factors, which are also liberated through matrix proteolysis. Recent organ culture studies using hypertrophied rat pulmonary arteries have shown that elastase inhibitors suppress tenascin-C and induce smooth muscle cell apoptosis. This initiates complete regression of the hypertrophied vessel wall by a coordinated loss of cellularity and extracellular matrix. We now report that elastase inhibitors can reverse advanced pulmonary vascular disease produced in rats by injecting monocrotaline, an endothelial toxin. We began oral administration of the peptidyl trifluoromethylketone serine elastase inhibitors M249314 or ZD0892 21 days after injection of monocrotaline. A 1-week treatment resulted in 92% survival, compared with 39% survival in untreated or vehicle-treated rats. Pulmonary artery pressure and muscularization were reduced by myocyte apoptosis and loss of extracellular matrix, specifically elastin and tenascin-C. After 2 weeks, pulmonary artery pressure and structure normalized, and survival was 86%, compared with 0% in untreated or vehicle-treated rats. Although concomitant treatment with various agents can reduce pulmonary hypertension, we have documented complete regression after establishment of malignant monocrotaline-induced disease.

A 26-year experience with surgical management of tetralogy of Fallot: risk analysis for mortality or late reintervention

BACKGROUND

Over the past decade repair of tetralogy of Fallot (TOF) in infancy has gained favor. It is still uncertain what effect early complete repair will have on survival or late reoperation on the right ventricular outflow tract.

METHODS

To assess these outcomes, we reviewed our experience (1971-1997) with 294 patients undergoing operation at one institution. Median follow-up was 10.6 years (range, 0.1 to 26 years), and was complete for 90.2% patients.

RESULTS

Primary complete repair was done in 199 patients (68%), and a staged repair in 62 patients (21%). Thirty-three patients had only a palliative procedure. Sixty-eight patients (23.1%) had complex pathologic processes, including pulmonary atresia in 53. Hospital mortality for primary repair was 11.1% (22/199), for staged repair was 17.7% (11/62), and for palliative procedures was 15.5% (16/103 procedures). Since 1990 mortality has been 2.1%, 11.8%, and 0% respectively (p < 0.001), despite younger age at repair (0.6+/-0.1 versus 2.1+/-0.2 years; p < 0.001). Multivariate analysis identified longer period of hypothermic circulatory arrest, pulmonary artery patch angioplasty, earlier year of operation, and closure of the foramen ovale as risk factors for hospital death. For hospital survivors 20-year survival was 98%+/-3% for TOF with pulmonary stenosis and 88%+/-9% for TOF with pulmonary atresia (p=0.09). Reintervention on the right ventricular outflow tract was needed in 14.1% (37/261) patients. Freedom from reintervention on the right ventricular outflow tract at 20 years was 86%+/-4% for TOF with pulmonary stenosis and 43%+/-16% for TOF with pulmonary atresia (p=0.001). For the subgroup TOF with pulmonary stenosis, this was 85%+/-5% after primary repair and 91%+/-8% after staged repair (not significant). At 15-year follow-up, this was 78%+/-10% for patients not older than 1 year at operation compared with 88%+/-4% for older patients (not significant).

CONCLUSIONS

Early mortality after primary repair of TOF has significantly improved and late survival is excellent. Primary repair in infancy does not increase risk for reintervention on the right ventricular outflow tract.

Right and left ventricular function assessed by regional wall motion analysis in patients with tetralogy of Fallot

We studied pre- and postoperative regional right and left ventricular wall motion and global ejection fraction in 18 patients with tetralogy of Fallot who had successful repair, and compared these values to those of patients with a history of Kawasaki disease as controls. Right ventricular ejection fraction was significantly lower in the preoperative group (52 +/- 4%) than that in the control group (57 +/- 4%), and that in the postoperative state (49 +/- 4%) was significantly lower than those in the control and preoperative groups. Left ventricular ejection fraction was significantly lower in the preoperative group (56 +/- 7%) than that in the control group (61 +/- 5%), while that in the postoperative state (64 +/- 6%) was significantly higher than those in the control and preoperative groups. Regional ventricular wall motion analysis revealed that shortening fractions in the tricuspid valve region were reduced in the preoperative patients and were persistent even after successful repair; those in the right ventricular outflow tract region were decreased after the correction. Regional left ventricular wall motion showed that shortening fractions in the anterolateral region were improved after the correction. We conclude that right ventricular dysfunction was present in the preoperative patients with tetralogy of Fallot and was persistent even after total correction.