Primary repair of tetralogy of Fallot in infancy

Role of great artery annulus ratio to predict transannular patch enlargement in repair of tetralogy of Fallot

Background

Traditionally, the pulmonary valve annulus (PVA) z-score is used to predict the requirement of transannular patch enlargement (TAPE) of right ventricular outflow tract (RVOT) and main pulmonary artery (MPA) in repair of tetralogy of Fallot (TOF). PVA z-score is highly variable and many other parameters are being reported to be accurate in predicting need of TAPE. In this study, we analyze the role of great artery annulus ratio (pulmonary valve annulus to aortic valve annulus ratio, PVA/AVA) to be used as a predictor for TAPE.

Methods

We analyzed 90 patients of TOF retrospectively who underwent repair between January 2021 and December 2021. The patients were divided as TAPE group who required TAPE of RVOT and MPA and non-TAPE group who did not have TAPE. Their baseline parameters, PVA Z-score, and cut-off great artery annulus ratio were compared.

Results

Total 44 (48.9%) patients had transannular patch (TAPE) repair and 46 (51.1%) patients had non-transannular patch repair. The great artery annulus ratio and PVA z-score was lower in case of TAPE group with statistical significance. Receiver operating characteristic curve analysis showed great artery annulus ratio as more accurate predictor of TAPE.

Conclusion

Great artery annulus ratio can be used as a simple and accurate predictor for transannular patch enlargement along with PVA z-score during repair of TOF.

Society for Cardiovascular Magnetic Resonance/European Society of Cardiovascular Imaging/American Society of Echocardiography/Society for Pediatric Radiology/North American Society for Cardiovascular Imaging Guidelines for the use of cardiovascular magnetic resonance in pediatric congenital and acquired heart disease : Endorsed by The American Heart Association

Cardiovascular magnetic resonance (CMR) has been utilized in the management and care of pediatric patients for nearly 40 years. It has evolved to become an invaluable tool in the assessment of the littlest of hearts for diagnosis, pre-interventional management and follow-up care. Although mentioned in a number of consensus and guidelines documents, an up-to-date, large, stand-alone guidance work for the use of CMR in pediatric congenital 36 and acquired 35 heart disease endorsed by numerous Societies involved in the care of these children is lacking. This guidelines document outlines the use of CMR in this patient population for a significant number of heart lesions in this age group and although admittedly, is not an exhaustive treatment, it does deal with an expansive list of many common clinical issues encountered in daily practice.

Society for Cardiovascular Magnetic Resonance/European Society of Cardiovascular Imaging/American Society of Echocardiography/Society for Pediatric Radiology/North American Society for Cardiovascular Imaging Guidelines for the Use of Cardiac Magnetic Resonance in Pediatric Congenital and Acquired Heart Disease: Endorsed by The American Heart Association

Cardiovascular magnetic resonance has been utilized in the management and care of pediatric patients for nearly 40 years. It has evolved to become an invaluable tool in the assessment of the littlest of hearts for diagnosis, pre-interventional management and follow-up care. Although mentioned in a number of consensus and guidelines documents, an up-to-date, large, stand-alone guidance work for the use of cardiovascular magnetic resonance in pediatric congenital 36 and acquired 35 heart disease endorsed by numerous Societies involved in the care of these children is lacking. This guidelines document outlines the use of cardiovascular magnetic resonance in this patient population for a significant number of heart lesions in this age group and although admittedly, is not an exhaustive treatment, it does deal with an expansive list of many common clinical issues encountered in daily practice.

Mortality Risk Factors in Tetralogy of Fallot Patients Undergoing Total Correction

A total correction is a preferred treatment for Tetralogy of Fallot patients in every part of the world. However, the mortality in developing countries was as high as 6.9% to 15.3%. This was a retrospective analytic study that analyzed pre and post-operative risk factors that affected mortality on TOF patients that were performed total correction in Indonesia. A total of 47 TOF patients that were performed total correction from January 2016 to September 2019 were enrolled in this study based on the inclusion criteria. Preoperative and post-operative data were obtained from medical records. In this research, the majority of mortality was found in male patients (39.3%), while the female’s rate was lower (36.8%). Overall mortality was 38.3% and one operative death was found. The average age of patients was 84.12 months (12-210 months), whereas the average height (85.56 ± 36.17cm vs. 112.93 ± 21.73) and weight (17.22kg vs. 28.21kg) were lower for mortality patients. Some significant preoperative variables were identified as mortality risk factors such as: age below 60 months (p=0.047), smaller weight and height (p=0.008; p=0.002), abnormal hematocrit (p=0.002), and oxygen saturation below 75% (p=0.018). Significant post-operative risk factors included: temperature above 38.5⁰C (p=0.000), and ventilator time of more than 48 hours (p=0.033). In conclusion, the mortality of TOF patients undergoing a total correction in developing countries was quite high. It was associated with some risk factors, such as younger age, lower weight and height, low oxygen saturation, post-operative fever, and prolonged ventilator time.

Value of pulmonary annulus index in predicting transannular patch in tetralogy of Fallot repair

OBJECTIVE

It is very important to accurately assess the transannular patch (TAP) in the surgical treatment of tetralogy of Fallot (TOF). The pulmonary annulus index (PAI; the actual pulmonary annulus diameter divided by the expected pulmonary annulus diameter), GA ratio (the ratio of pulmonary annulus and aortic annulus), PAAI (the ratio of pulmonary annulus cross-section and aortic annulus cross-section), and pulmonary annulus Z score (PA Z score) were compared. This study aimed to analyze and explore the application value of PAI in predicting the need for TAP in children undergoing TOF repair.

METHODS

In total, 130 patients who were diagnosed with TOF and underwent TOF repair in Beijing Anzhen Hospital affiliated to Capital Medical University from December 2018 to December 2019 were retrospectively studied. In total, 112 cases were included in this study and 18 cases were excluded, of which 16 cases were aged above 18 years and 2 cases suffered from Down syndrome. They were divided into TAP group and no TAP group; the values of the pulmonary annulus and aortic annulus were measured. GA ratio, PAI, PAAI, the pulmonary annulus Z score, and main pulmonary artery (MPA) Z score were calculated to perform statistical analysis.

RESULTS

A total of 112 patients were included in the study, aged 4-177 months, with an average of 22.87 ± 30.21 months; 66 males and 46 females; weighing 5.3-29 kg, with an average of 9.94 ± 4.08 kg; three cases died, one case died of sepsis caused by pulmonary infection, one case died of low cardiac output syndrome, and one case died of multiple organ failure. In total, 62 cases (55.8%) did not undergo TAP and 50 cases (44.2%) underwent TAP. The pulmonary annulus Z score, main pulmonary artery Z score, and PAI in the TAP group were smaller than those in the no TAP group (p < .05). Receiver operating curve (ROC) analysis showed that when the cut-off value of pulmonary annulus was -1.98, the area under the curve (AUC) was 0.88, the sensitivity was 80%, and the specificity was 71%; when the cut-off value of PAI was 0.53, AUC was 0.85, the sensitivity was 75%, and the specificity was 80%; when the cut-off value of GA ratio was 0.55, AUC was 0.85, the sensitivity was 76%, and the specificity was 80%. The area under the PAAI curve was 0.85, the sensitivity was 76%, and the specificity was 79%. When the pulmonary valve Z score, PAI, GA ratio, PAAI, and MPA Z score were all greater than the dividing value, TAP was avoided in more than 90% of children with TOF. When the pulmonary valve Z score, PAI, GA ratio, PAAI, and the main pulmonary artery Z score were all below the dividing value, more than 90% of children with TOF needed TAP.

CONCLUSION

The predictive effect of PAI as a simple and effective predictor of TAP in TOF radical operation is the same as that of pulmonary annulus Z score, and combining it with the main pulmonary artery Z score was the most accurate method of prediction.

Outcomes of pulmonary valve leaflet augmentation for transannular repair of tetralogy of Fallot

OBJECTIVE

To evaluate the midterm results of pulmonary valve leaflet augmentation in transannular repair of tetralogy of Fallot (TOF).

METHODS

From 2007 to 2019, 131 patients underwent a transannular repair with pulmonary leaflet augmentation for TOF (n = 120) and double outlet right ventricle with pulmonary stenosis (n = 11). Patch material was expanded polytetrafluoroethylene (n = 76), glutaraldehyde-treated autologous pericardium (n = 47) and bovine pericardium (n = 8).

RESULTS

Median age at repair was 8.9 months (interquartile range, 5.4-14.8). There was no operative mortality. Median follow-up was 6.25 years (interquartile range, 2.77-7.75). Freedom from severe pulmonary regurgitation (PR) was 85% (95% confidence interval [CI], 77%-90%) and 76% (95% CI, 66%-83%) at 1 and 5 years, respectively. Freedom from moderate or greater PR was 69% (95% CI, 60%-76%) and 30% (95% CI, 21%-39%) at 5 and 10 years, respectively. Three patients required pulmonary valve replacement for PR. Nine patients required pulmonary balloon valvuloplasty. Freedom from intervention for pulmonary valve stenosis was 98% (95% CI, 93%-99%) and 94% (95% CI, 87%-97%) at 1 and 5 years, respectively. One patient with severe PR had an indexed right ventricular volume >160 mL/m². Use of expanded polytetrafluoroethylene resulted in a greater freedom from moderate or greater PR (log-rank test P < .001; Cox regression hazard ratio, 0.40; 95% CI, 0.25-0.63; P < .001).

CONCLUSIONS

At midterm follow-up of transannular repair with pulmonary valve leaflet augmentation, severe PR occurs in less than 50% of patients. The expanded polytetrafluoroethylene patch performs better than pericardium.

Value of pulmonary annulus area index in predicting transannular patch placement in tetralogy of Fallot repair

BACKGROUND

Precisely evaluating the need for transannular patch (TAP) placement is very important in the surgical treatment of tetralogy of Fallot. We hypothesized that the pulmonary annulus area index (PAAI, the pulmonary-to-aortic valve annulus cross-sectional area ratio) could be a useful and accessible predictor for TAP placement.

METHODS

The medical records of patients who underwent tetralogy of Fallot repair between 1 January 2016 and 31 December 2017 were reviewed retrospectively. A total of 255 patients were included and categorized into two groups: patients who needed TAP placement and patients who did not. Various candidate predictors for TAP placement (PAAI, pulmonary annulus z-score, and velocity across the pulmonary annulus) were compared using receiver operating characteristic curves. The optimal cutoff for each predictor was assessed.

RESULTS

Among the 255 patients included, 156 needed TAP placement (156/237, 65.8%). Both the PAAI (0.28 [0.20/0.34] vs 0.14 [0.09/0.19]; P < .0001) and z-score (-1.5 [-2.9, -0.4] vs -3.6 [-5.3/-2.6]; P < .0001) were smaller in the TAP group. The PAAI is a useful predictor of the pulmonary annulus z-score (AUC 0.830 vs 0.811, P = .19). Combination analysis of the PAAI and velocity across the pulmonary annulus (PV v_max ) showed better predictive value than the PAAI and z-score (AUC 0.860, sensitivity 89.7%, specificity 61.7%, P < .0001).

CONCLUSIONS

Our results suggest that the PAAI is a useful and accessible predictor for TAP placement and can be applied readily and simply in clinical practice. A combination with the velocity across the pulmonary annulus could promote the accuracy of prediction.

Factors associated with perioperative mortality in children and adolescents operated for tetralogy of Fallot: A sub-Saharan experience

BACKGROUND

Patients with tetralogy of Fallot are now surviving to adulthood with timely surgical intervention. However, many patients in low-income countries have no access to surgical intervention. This paper reports the surgical access and perioperative mortality in a sub-Saharan center that was mainly dependent on visiting teams.

METHODS

We reviewed records of patients operated from January 2009 to December 2014. We examined perioperative outcomes, primarily focusing on factors associated with perioperative mortality.

RESULTS

During this period, 62 patients underwent surgery. Fifty-seven (91.9%) underwent primary repair, while 5 (6.5%) underwent palliative shunt surgery. Of the five patients with shunt surgery, four ultimately underwent total repair. Eight (12.9%) patients died during the perioperative period. Factors associated with perioperative mortality include repeated preoperative phlebotomy procedures (P < .001), repeated runs and long cardiopulmonary bypass time (P < .001), and aortic cross-clamp time (P < .001), narrow pulmonary artery (PA) valve annulus diameter (P = .022), narrow distal main PA diameter (P = .039), narrow left branch PA diameter (P = .049), and narrow right PA diameter (P = .039). Of these factors, cardiopulmonary bypass time/aortic cross-clamp time and pulmonary valve annulus diameter less than three SD were independently associated with perioperative mortality.

CONCLUSION

In this series of consecutive patients operated by a variety of humanitarian surgical teams, cardiopulmonary bypass time/aortic cross-clamp time, and pulmonary valve annulus diameter less than three SD were independently associated with perioperative mortality risk. As some of these factors are modifiable, we suggest that they should be considered during patient selection and at the time of surgical intervention.

Accuracy of a New Echocardiographic Index to Predict Need for Trans-annular Patch in Tetralogy of Fallot

The long-term outcome after repair of tetralogy of Fallot (TOF) is critically dependent pulmonary valve competence that is compromised by trans-annular patch (TAP). We compared a new echocardiographic index [pulmonary annulus index (PAI)] to conventional methods of predicting need for TAP in infants undergoing TOF repair. Consecutive infants undergoing TOF repair were prospectively studied. Pre-operative aortic and pulmonary annuli and main pulmonary artery (MPA) diameters were measured and z scores determined. PAI was a ratio of observed to expected pulmonary annulus (PA) diameter. TAP was based on intra-operative sizing by surgeons blinded to PAI values. Receiver operator curves (ROC) were generated for all PAI, MPA z scores and pulmonary annulus z scores. Of 84 infants (8.6 ± 2.6 months; 7.5 ± 1.3 kg), 36 needed TAP (43%). All the three indices viz. PAI, Pulmonary annulus and MPA z scores performed similarly in predicting need for TAP (ROC curves ~ 80%). Combining cut-offs of MPA z scores (> - 3.83) with either PAI (> 0.73) or PA z score (> - 1.83) predicted avoidance of TAP with ~ 90% accuracy. When both PAI and MPA z scores were below the cut-offs there was an 80% likelihood of TAP. Failure to predict TAP was associated with unicommisural pulmonary valves. PAI was equal to PA z scores in predicting need for TAP during repair of TOF. Combining either with MPA z scores was the most accurate method of prediction. Failure of prediction was mainly due to presence of a unicommissural pulmonary valve.

Investigation of associated factors with post-operative outcomes in patients undergoing Tetralogy of Fallot correction

Background

Tetralogy of Fallot (TOF) is one of the congenital cardiac abnormality which occurs during embryonic time. Although surgical correction, especially early operation, is the best way to treat patients, still contributing factors in morbidity and mortality is controversial. The objective of this study is to investigate potential factors which might be correlated with post-operative outcomes of TOF.

Methods

In this retrospective study, 349 monitored patients with TOF correction were selected. Median of age was 4 (0.66–8) year, 58% of patients were male and 42% were female. Time of inotropic drug, extubation time, and ICU stay were considered as post-operative outcomes which extension of each of them increased the risk of death.

Results

Ventricular septal defect enlargement was associated with longer extubation time and ICU stay. Higher ratio of pre-operative haematocrit was correlated with mortality (0.047).

Conclusions

Results of this study demonstrated that haematocrit ratio before operation should be considered as a predictive factor, and patients with higher ratio of haematocrit require more care after operation. VSD enlargement is associated with longer extubation time and ICU stay.

Clinical Progress in the Management of Tetralogy of Fallot in the Dominican Republic: A Case Series

BACKGROUND

Definitive surgical interventions for Dominican children with congenital heart disease, like those of other low- and middle-income countries, have been historically limited.

METHODS

We undertook review of a case series focusing on the surgical correction of complex forms of tetralogy of Fallot at a single center, CEDIMAT Centro Cardiovascular, in the Dominican Republic, over a 30-month period.

RESULTS

According to our criteria, 43 cases were determined to be complex tetralogy of Fallot repairs from the two-year period. Besides tetralogy of Fallot, the cohort had an additional 55 anatomic anomalies that had to be addressed at the time of surgery. Median age at the time of surgery was notably 30 months, and an average of 42 months elapsed from the time of diagnosis to the time of surgery for this group. Only 33% of the cases reviewed had no hypercyanotic crises before repair. Median time to extubation for this group of patients was one day, with a three-day median length of stay in the intensive care setting.

CONCLUSIONS

Our study importantly captures the present experience of a surgical congenital heart program that has recently transitioned from a traditional "mission model" to a now self-sustaining local practice. Both the number and the complexity of the lesions corrected in this caseload represent an advance from the level of care previously provided to children in the Dominican Republic.

Predictors of Intensive Care Unit Morbidity and Midterm Follow-up after Primary Repair of Tetralogy of Fallot

Background

Our objectives were to review our institutional early and midterm experience with primary tetralogy of Fallot (TOF) repair, and identify predictors of intensive care unit (ICU) morbidity.

Methods

We analyzed perioperative and midterm follow-up data for all cases of primary TOF repair from 2001 to 2012. The primary endpoint was early mortality and morbidity, and the secondary endpoint was survival and functional status at follow-up.

Results

Ninety-seven patients underwent primary repair. The median age was 4.9 months (range, 1 to 9 months), and the median weight was 5.3 kg (range, 3.1 to 9.8 kg). There was no early surgical mortality. The incidence of junctional ectopic tachycardia and persistent complete heart block was 2% and 1%, respectively. The median length of ICU stay was 6 days (range, 2 to 21 days), and the median duration of mechanical ventilation was 19 hours (range, 0 to 136 hours). By multiple regression analysis, age and weight were independent predictors of the length of ICU stay, while the surgical era was an independent predictor of the duration of mechanical ventilation. At the 8-year follow-up, freedom from death and re-intervention was 97% and 90%, respectively.

Conclusion

Primary TOF repair is a safe procedure with low mortality and morbidity in a medium-sized program with outcomes comparable to national standards. Age and weight at the time of surgery remain significant predictors of morbidity.

Primary tetralogy of Fallot repair: Predictors of intensive care unit morbidity

Background

Primary repair of tetralogy of Fallot has low surgical mortality, but some patients still experience significant postoperative morbidity. Our objectives were to review our institutional experience with primary tetralogy of Fallot repair, and identify predictors of intensive care unit morbidity.

Methods

We reviewed all patients with tetralogy of Fallot who underwent primary repair in infancy from 2001 to 2012. Preoperative, operative, and postoperative demographic and morphologic data were analyzed. Intensive care unit morbidity was defined as prolonged intensive care unit stay (≥7 days) and/or prolonged duration of mechanical ventilation (≥48 h).

Results

97 patients who underwent primary surgical repair during the study period were included in the study. The median age was 4.9 months (range 1–9 months) and the median weight was 5.3 kg (range 3.1–9.8 kg). There was no early surgical mortality. The incidence of junctional ectopic tachycardia and persistent complete heart block was 2% and 1%, respectively. The median intensive care unit stay was 6 days (range 2–21 days) and the median duration of mechanical ventilation was 19 h (range 0–136 h). Age and weight were independent predictors of intensive care unit stay, while surgical era predicted the duration of mechanical ventilation.

Conclusion

Primary tetralogy of Fallot repair is a safe procedure with low mortality and morbidity in a medium-sized program with outcomes comparable to national standards. Age and weight at the time of surgery were significant predictors of morbidity.

Is there any need for a shunt in the treatment of tetralogy of Fallot with one source of pulmonary blood flow?

OBJECTIVES

In symptomatic patients, performing a primary repair of tetralogy of Fallot (TOF), irrespective of age or placing a shunt, remains controversial. The aim of the study was to analyse the policy of primary correction.

METHODS

Between May 2005 and May 2012, a total of 87 consecutive patients with TOF, younger than 6 months of age, underwent primary correction. All patients had one source of pulmonary blood flow, with or without a patent ductus arteriosus. The median age at surgery was 106 ± 52.3 days (8-180 days). Twelve patients (13.8%) were newborns. Two groups were analysed: group I, patients <1 month of age; group II, patients between 2-6 months of age.

RESULTS

There was no early or late death at 7 years of follow-up. There was no difference in bypass time or hospital stay between the two groups, but the Aristotle comprehensive score (P < 0.0001), ICU stay (P = 0.030) and the length of ventilation (P = 0.014) were significantly different. Freedom from reoperation was 87.3 ± 4.3% and freedom from reintervention was 85.9 ± 4.2% at 7 years, with no difference between the two groups. Neurological development was normal in all patients, but 1 patient in Group II had cerebral seizures and showed developmental delay. Growth was adequate in all patients, except those with additional severe non-cardiac malformations that caused developmental delay. Eighty-five per cent of the patients were without cardiac medication.

CONCLUSIONS

Even in symptomatic neonates and infants <6 months of age, primary repair of TOF can be performed safely and effectively. One hundred per cent survival at 7 years suggests that early primary repair causes no increase in mortality in the modern era. Shunting is not necessary, even in symptomatic newborns, thus avoiding the risk of shunt-related complications and repeated hospital stays associated with a staged approach.

Assessment of coronary flow reserve in the coronary sinus by cine 3T-magnetic resonance imaging in young adults after surgery for tetralogy of Fallot

This study aimed to evaluate CFR by assessing blood flow in the coronary sinus and systemic endothelial function measured by FMD of the brachial artery in an open prospective study of 10 control subjects and 10 patients (ages, 15-25 years) who have undergone surgical TOF repair. Reduced ventricular function, impaired exercise capacity, and ventricular arrhythmia have been proposed as risk factors for sudden cardiac death after surgical repair of TOF. Some of this may be related to impaired myocardial perfusion. A 3.0T GE Signa Excite scanner was used to achieve phase-contrast, velocity-encoding cine magnetic resonance imaging in the coronary sinus before and during infusion with adenosine (0.14 mg/kg/min). FMD was measured in the brachial artery before arterial occlusion and 5 min afterward. The TOF group demonstrated significantly higher volumetric blood flow in the coronary sinus (282 ± 63 ml/min) than the normal control subjects at rest (184 ± 57 ml/min) (P = 0.006). During adenosine infusion, this difference disappeared. The CFR was 2.00 ± 0.43 in the control group and 1.19 ± 0.34 in the TOF group (P = 0.002). No correlation between FMD and CFR was observed in the study group (r (s) = 0.61, n = 8, P = 0.15). This study showed a reduced CFR due to a higher blood flow of the subject at rest in the TOF group. This reduced CFR may disable a normal adaptation to increased oxygen demand during exercise and increase myocardial vulnerability to reduced blood supply postoperatively for TOF patients with coronary heart disease.

Tetralogy of Fallot repair: the Right Ventricle Infundibulum Sparing (RVIS) strategy

Despite the excellent operative survival for tetralogy of Fallot (TOF) repair, well-documented long-term complications and reduced life expectancy remain challenges for these patients and their clinicians. In an attempt to change the natural history of repaired TOF, we at Texas Children's Hospital (Houston, TX) have developed a management strategy not focused on age, but rather focused on preserving the right ventricular (RV) infundibulum. The RV infundibulum sparing (RVIS) repair of TOF consists of a transatrial and transpulmonary approach to close the ventricular septal defect and resect RV infundibular muscle coupled with a mini (< 5 mm) transannular patch or no ventricular incision. This strategy is applied with the ambition of decreasing the well-documented, long-term complications of TOF repair with large right ventriculotomies such as RV dilation, arrhythmias, need for pulmonary valve replacement, and RV failure. The RVIS strategy is an attempt based on our current knowledge and experience to optimize the time of repair so that we can not only maximize the early operative results but the long-term effects of this approach as these children mature into adolescents and adults. We have uniformly applied the RVIS strategy since 1995, which includes over 320 isolated TOF patients. We are currently reviewing this cohort in hopes that it will strengthen our beliefs and known results as well as give us more insight into whether the RVIS strategy can change the natural history of repaired TOF.

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.

Pulmonary valve cusp augmentation with autologous pericardium may improve early outcome for tetralogy of Fallot

OBJECTIVES

The transannular patch used to relieve right ventricular outflow tract obstruction in children with tetralogy of Fallot may result in pulmonary insufficiency. We hypothesized that pulmonary valve cusp augmentation with pericardium would decrease pulmonary insufficiency and improve the early outcome for transatrial-transpulmonary tetralogy of Fallot repair requiring transannular patch.

METHODS

Since November 2001, 41 patients with tetralogy of Fallot and 2 patients with isolated pulmonary valve stenosis had relief of right ventricular outflow tract obstruction with either a transannular patch plus pulmonary valve cusp augmentation (n = 18) or a transannular patch alone (n = 25). Data were retrospectively collected.

RESULTS

The median age (5.3 vs 3.2 months; P = .09) and weight (6.4 vs 5.2 kg; P = .3) were similar for the cusp augmentation and transannular patch groups, respectively. The diameter of the pulmonary valve annulus (6.4 vs 6.0 mm; P = .57) and the McGoon index (1.47 vs 1.69, P = .75) were also similar. The mean aortic clamp time (48 +/- 18 minutes vs 52 +/- 19 minutes; P = .46) and median cardiopulmonary bypass time (89 vs 91 minutes; P = .9) did not differ. One patient with a transannular patch died of multiorgan system failure. Patients with a pulmonary valve cusp augmentation had a shorter duration of intubation (1 vs 3 days; P < .001) and intensive care unit stay (2 vs 8 days; P < .001). Thirteen patients with a transannular patch and 1 patient with a pulmonary valve cusp augmentation required inotropic support for more than 72 hours (P = .001). Discharge echocardiograms demonstrated moderate or severe pulmonary insufficiency in 5 patients with a pulmonary valve cusp augmentation and in 21 patients with a transannular patch (P < .001). At 7.5 months, 3 patients (17%) with a pulmonary valve cusp augmentation had progression of pulmonary insufficiency.

CONCLUSIONS

Augmentation of a pulmonary valve cusp reduces the incidence of clinically significant postoperative pulmonary insufficiency. This technique may improve the early outcome for children with tetralogy of Fallot requiring a transannular patch.

Medium term outcome for infant repair in tetralogy of Fallot: Indicators for timing of surgery

OBJECTIVE

To assess the impact of early corrective surgery on the short and medium term outcome in tetralogy of Fallot (TOF).

MATERIALS AND METHODS

All patients under 12 months of age undergoing correction of isolated TOF between February 1997 and July 2003 were reviewed retrospectively. Outcome data for mortality, post-operative care management, major morbidity and clinical follow-up were analysed.

RESULTS

Fifty-two operations were performed. The mean age at surgery was 5 months (range 1-12) of whom 16 (30.8%) were less than 3 months old, including 2 neonates, 22 (42.3%) were 3-6 months old and 14 (26.9%) were 7-12 months old. There was 1 (1.9%) early death caused by a cerebro-vascular accident and 1 (1.9%) late death secondary to acute infective endocarditis. There were no differences in post-operative morbidities attributable to age. Patients under 3 months old required greater duration of post-operative ventilation, ITU stay and in-hospital stay. At a mean follow-up of 4.0 years (range 1.5-8.0), 33 (63.5%) patients had well-tolerated pulmonary regurgitation (PR) and 3 (5.8%) patients required re-operation for right ventricular outflow tract obstruction (RVOTO). All patients had right bundle-branch-block but with QRS < 150 ms.

CONCLUSION

Early definitive repair of TOF can be performed safely on patients under 6 months old. Age at surgery does not appear to affect the medium term haemodynamic outcome. However, early surgery does escalate the need for ICU care. This data suggests repair in asymptomatic patients be delayed until 3-6 months of age.

The influence of perioperative factors on outcomes in children aged less than 18 months after repair of tetralogy of Fallot

OBJECTIVES

To determine the impact of age at repair in patients with tetralogy of Fallot on early postoperative morbidity.

METHODS

All patients less than 19 months of age (median age, 8 months; range, 36 days-18.5 months) who underwent complete repair of tetralogy of Fallot between January 1997 and December 1999 were reviewed. Data were analyzed on the preoperative clinical and anatomical characteristics, operative procedure and postoperative course in the intensive care unit. Independent factors associated with intensive care unit stay were sought using Cox's proportionate hazard modeling. In addition, independent factors associated with an intensive care unit stay of more than 2 days were sought in multiple logistic regression analysis.

RESULTS

Seventy-eight patients underwent surgical repair; 3 had (4%) had a previous systemic to pulmonary arterial shunt. There was no operative mortality. One late death occurred. The median intensive care unit length of stay and mechanical ventilation time were 2 days (range, 1-14) and 16.2 hours (range, 0-267), respectively. Age less than 3 months was associated with increased use of vasoactive drugs, higher postoperative fluid requirement, and a higher incidence of organ dysfunction but no patient required renal replacement therapy. The duration of ventilator support and the intensive care unit length of stay were also longer in this age group.

CONCLUSIONS

Primary repair at an early age has excellent short-term outcome. Patients less than 3 months of age have an increased but transient intensive care unit morbidity.

Repair of tetralogy of Fallot in infancy with a transventricular or a transatrial approach

OBJECTIVE

The optimal time and approach of repair of tetralogy of Fallot (TOF) remain controversial. The purpose of this study was to evaluate the outcome following repair of TOF in infants with particular regard to the surgical approach used.

PATIENTS

One hundred and sixty infants (mean age 195+/-89 days, range 11-364 days) undergoing repair of a simple TOF were studied. Between 1974 and 2000, a transventricular approach (RV) was used in 91 and between 1988 and 2000, a transatrial (RA) approach in 69 infants. Ten of these infants (6.2%) had a previous palliative shunt (four in the RV versus six in the RA group). A transannular patch (TAP) was inserted in 96 (60%) infants (76 versus 20). Follow-up was complete (mean 14.5+/-5.2 versus 6+/-1 years).

RESULTS

There were three operative deaths (1.9%), (two in RV versus one in RA group). A re-operation for right ventricular outflow tract obstruction (RVOTO) was performed in 19 patients (3 versus 16). Ten-year freedom from re-operation for RVOTO (+/-standard error of the mean) was 88+/-4% (98+/-2 versus 72+/-6%, P<0.0001). Within the RA group, 5-year freedom from re-operation for RVOTO for those who had a TAP was 79+/-9% and it was 75+/-4% for those having a simple repair. Six patients in the RV group required pulmonary valve replacement (PVR). Ten-year freedom from PVR was 98+/-1% (97+/-2 versus 100%, P=0.3). There were two late deaths, one in each group. Ten-year survival was 97+/-1%. One patient in the RV group developed late recurrent ventricular tachycardia requiring the implantation of a defibrillator. At most recent echocardiography, all but the patient who had the defibrillator had good right and left ventricular function.

CONCLUSIONS

Transventricular and transatrial repair of TOF in infancy, are associated with an acceptable operative risk, low incidence of late arrhythmia, good bi-ventricular function and excellent survival. In our experience, however, transatrial repair has a disturbing incidence of early and mid-term residual or recurrent RVOTO, even when a TAP has been used.

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

Tetralogy of Fallot: surgical management individualized to the patient

BACKGROUND

Over the past four decades, the surgical trend has been toward early, complete repair of tetralogy of Fallot (TOF). Many centers currently promote all neonates for total correction irrespective of anatomy and symptoms, with some surgeons advocating hypothermic circulatory arrest for repair in small infants. We believe this approach increases morbidity.

METHODS

Based on approximately 40 years' experience in 2,175 patients, we developed a management protocol focused on patient size, systemic arterial saturations, and anatomy. Symptomatic patients (hypercyanotic spells, ductal dependent pulmonary circulation) weighing less than 4 kg undergo palliative modified Blalock-Taussig shunt (BTS) followed by complete repair at 6 to 12 months. Asymptomatic patients, weighing less than 4 kg who have threatened pulmonary artery isolation, undergo BTS and repair at 6 to 12 months. All other patients undergo complete repair after 6 months.

RESULTS

From July 1, 1995, to December 1, 1999, 144 patients underwent operation for TOF (129 patients) or TOF with atrioventricular septal defect (TOF/AVSD, 15 patients). Ninety-four patients underwent one stage complete repair (88 TOF, 6 TOF/AVSD). Thirty-nine patients underwent repair after initial BTS (32 TOF, 7 TOF/AVSD). Ten patients are awaiting repair after BTS. The mean age and weight at complete repair were 18 months and 9 kg. There were no operative deaths. There have been 3 late deaths with complete follow-up (mortality 3 of 144 [2.1%]). Four of 133 patients (3%) have required reoperation after total correction.

CONCLUSIONS

This management strategy optimizes outcomes by individualizing the operation to the patient. Advantages include avoidance of circulatory arrest, low morbidity and mortality, and low incidence of reoperation after complete repair.

Outcome after repair of tetralogy of Fallot in the first year of life

BACKGROUND

The purpose of this study was to evaluate the early and late outcome after repair of tetralogy of Fallot in the first year of life.

METHODS

Between 1974 and 2000, 89 consecutive infants with a mean age of 6.3 +/- 2.6 months (range, 15 days to 12 months) underwent repair of tetralogy of Fallot (ventricular septal defect and pulmonary stenosis) by one surgeon (J.L.M.). Three infants had previous palliative operations. Sixty-seven procedures were urgent or emergency. A transannular patch was inserted in 69 patients (77.5%). Follow-up was complete, averaging 13.4 +/- 5.6 years (range, 0 to 25.4 years).

RESULTS

There was one operative death (1.1%). Mean right ventricular to left ventricular pressure ratio postoperatively was 0.4 +/- 1.1 (in 79 patients, < 0.5). Fourteen patients underwent reoperations or reinterventions. There were no reoperations for residual or recurrent ventricular septal defect. Kaplan-Meier freedom from reoperation or reintervention for any cause at 20 years was 85% +/- 4.4%, for relief of right ventricular outflow tract obstruction it was 94% +/- 3.1%, and for pulmonary valve replacement this was 95.4% +/- 2.6%. Use of a transannular patch did not significantly affect the need for reoperation or reintervention. There was one late death (leukemia). Kaplan-Meier 20-year survival was 97.8% +/- 1.9%. On latest echocardiography, 42 patients had moderate pulmonary regurgitation, 4 had a right ventricular outflow tract gradient more than 40 mm Hg, and 86 had good biventricular function. Twelve-lead electrocardiography was performed in all and 24-hour electrocardiography in 61 patients. One patient (1.1%) exhibited late recurrent ventricular tachycardia requiring implantation of a defibrillator. The remaining 86 patients are in New York Heart Association class I with none of them receiving antiarrhythmic medications.

CONCLUSIONS

These data strongly support the concept of early repair of tetralogy of Fallot. It is associated with an acceptable operative risk and a low incidence of significant arrhythmias, and provides long-term survival similar to that observed in the general population. Late complications may, however, develop, and long-term follow-up for their early recognition is essential.

Elective primary repair of acyanotic tetralogy of Fallot in early infancy: overall outcome and impact on the pulmonary valve

OBJECTIVES

We sought to determine if early primary repair of acyanotic tetralogy of Fallot (ToF) can be performed safely with low requirement for transannular patching (TAP) and thereafter allow normal right ventricular outflow tract (RVOT) growth.

BACKGROUND

Early primary repair of ToF normalizes intracardiac flow patterns, which may allow subsequent normal RVOT growth. Traditionally repair is deferred until symptoms occur or children are deemed of adequate size for operative risk to be acceptable because of a perceived increased requirement for TAP in small infants.

METHODS

Between July 1992 and March 1999, 42 acyanotic infants aged 4 to 87 days (median 62) and weight 2.6 to 6.6 kg (median 4.55) underwent complete repair of ToF. Pulmonary annulus measured 4 to 10.5 mm (median 6.5) with "z-value" of-5.6 to +3.0 (median -1.9). RVOT reconstruction was tailored to each patient; pulmonary valvotomy was performed in 26, main pulmonary arterioplasty in 22, and infundibular patching in 2. Only 10 (24%) required TAP.

RESULTS

Postoperative RVOT gradient was 0 to 30 mm Hg (median 10) and pRV/pLV ratio 0.3 to 0.6 (median 0.44). Pulmonary insufficiency was trivial/mild. There were no deaths. Junctional ectopic tachycardia developed in seven; only one required treatment. ICU stay was 2 to 14 days (median 4) and hospital stay 4 to 22 days (median 7). At follow-up 12 to 64 months later (median 38) there were no deaths. One child required reoperation for recurrent RVOT obstruction and two required balloon pulmonary arterioplasty. Follow-up RVOT gradient was 0 to 36 mm Hg (median 12), unchanged from early postoperative condition, and median z-value was -1.2 (-2.8 to +2.5); pulmonary insufficiency remained trivial/mild.

CONCLUSIONS

Complete repair of acyanotic ToF can be performed in early infancy with low morbidity and mortality and low requirement for TAP. Though results are not statistically significant, early repair may allow normal RVOT growth thereafter.

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.

Tetralogy of Fallot: what operation, at which age

BACKGROUND

The optimal management of tetralogy of Fallot is still under debate, particularly with respect to surgical approach and the age of operation. In recent times a transatrial-transpulmonary approach and primary repair in younger patients is favoured. The purpose of the present study was to analyze the result of our current surgical management by assessing the perioperative and intermediate term follow up in order to define the optimal strategy and timing of operation for our institution.

METHODS

One hundred and thirty two patients with tetralogy of Fallot who underwent definitive repair between May 1993 and December 1998 were analyzed by reviewing their medical records and follow-up. Median age was 15. 5 (2.3-68.6) months and median weight was 8.8 (5-16) kg. Ten (7.57%) patients were under 6 months, 38 (28.78%) were between 6 and 12 months, 36 (27.27%) were between 12 and 18 months, 23 (17.42%) were between 18 and 24 months and 25 (18.93%) were more than 24 months age. During the study period there was a move to earlier surgery and differing methods of repair depending on the anatomy observed. Follow up was conducted by the referring cardiologist. Median follow up was 35.48 (8.07-74.93) months.

RESULTS

Forty-two (31.8%) patients required a palliative procedure before total correction due to unfavourable anatomy. Subpulmonary infundibular obstruction with a fibrous component increased significantly with age (P<0.05). Operations were entirely transatrial in 14 (10.6%), transatrial and transpulmonary in 69 (52.2%), transatrial and transventricularly in 42 (31.8%) and a homograft conduit was used in seven (5.3%) patients. Younger patients had narrower pulmonary valves and required a transannular patch more frequently. All patients were in sinus rhythm, 28 (21.1%) showing right bundle branch block. Median hospital stay was 8 (5-54) days. No patient required reintervention during follow up and there was no early or late mortality.

CONCLUSION

Correction of tetralogy of Fallot at younger age does not increase morbidity or mortality and has potential advantages. A surgical technique adapted to the anatomy of the right ventricular outflow tract, achieves the best results.

Primary repair minimizing the use of conduits in neonates and infants with tetralogy or double-outlet right ventricle and anomalous coronary arteries

OBJECTIVE

The purpose of this study was to review our results with an approach of early primary repair for tetralogy of Fallot or double-outlet right ventricle with anomalous coronary arteries, using several techniques to minimize the use of a conduit.

METHODS

Twenty consecutive neonates and infants with anomalous coronary arteries crossing an obstructed right ventricular outflow tract underwent primary repair. Median age was 5.5 months and mean weight 6.22 kg. The anomalous coronary arteries included the left anterior descending from the right coronary artery (n = 10), the right coronary artery from the left anterior descending (n = 1), the left anterior descending from the right sinus (n = 1), and a significant conal branch from the right coronary artery (n = 7) or left anterior descending (n = 1). Two neonates had pulmonary atresia. The right ventricular outflow tract was reconstructed without a conduit in 18 patients, including those with pulmonary atresia. Surgical techniques included main pulmonary artery translocation in 4 patients, transannular repair under a mobilized left anterior descending coronary artery in 2 patients, and displaced ventriculotomy with subcoronary suture lines in 8 patients. In 4 patients the right ventricular outflow tract was repaired via the ventriculotomy and/or pulmonary arteriotomy. A homograft was used as the sole right ventricle-pulmonary artery connection in 1 patient and in another a homograft was added to a hypoplastic native pathway.

RESULTS

There have been no early or late deaths. The right ventricular/left ventricular pressure ratio within 48 hours of the operation was 0.47 +/- 0.10. There were 2 reoperations at 8 and 11 years after the operation, during a mean follow-up of 5.2 years (1-11.3 years).

CONCLUSIONS

Primary repair of tetralogy of Fallot or double-outlet right ventricle with anomalous coronary arteries can be done in neonates and infants with excellent results. Alternative surgical techniques for right ventricular outflow tract reconstruction, such as main pulmonary artery translocation, can avoid the use of a conduit in most patients.

Surgical management of tetralogy of Fallot in the first year of life

BACKGROUND

The surgical approach to tetralogy of Fallot (TOF) continues to evolve and now many centers favor early repair for TOF.

METHODS

Our experience includes 82 consecutive patients less than 1 year old with TOF (n = 74) and TOF with pulmonary atresia (n = 8) who were operated on between January 1992 and March 1998. Mean age at repair was 5.2 +/- 1.2 months and mean weight was 4.5 +/- 0.4 kg. Seven patients (anomalous left anterior descending artery [n = 1], pulmonary atresia with hypoplastic pulmonary arteries [n = 6]), underwent palliative procedures in the neonatal period followed by complete repair. Forty-nine patients (59%) were symptomatic (severe cyanosis or hypoxic spells), and 33 patients (41%) were asymptomatic. A combined transatrial-transpulmonary approach was employed in 28 patients (34%), and transannular patch or conduit for reconstruction of the right ventricular outflow tract (RVOT) was required in 54 patients (66%). The mean Nakata index was 160 +/- 25 mm2/m2.

RESULTS

There were no hospital deaths. Mean post-repair peak right ventricular/systemic pressure ratio was 0.48 +/- 0.1. There were no late deaths or reoperations during a mean follow-up of 23 +/- 5 months. All patients are currently asymptomatic and in New York Heart Association class 1. Postoperative evaluation by two-dimensional and Doppler echocardiography or cardiac catheterization showed minimal pulmonary artery stenosis with a mean pressure gradient of 15 +/- 6 mm Hg across the RVOT.

CONCLUSIONS

Our experience suggests that early repair of TOF can yield excellent results and initial palliation does not preclude early complete repair.

Adaptation to chronic hypoxia confers tolerance to subsequent myocardial ischemia by increased nitric oxide production

Chronic exposure to hypoxia from birth increased the tolerance of the rabbit heart to subsequent ischemia compared with age-matched normoxic controls. The nitric oxide donor GSNO increased recovery of post-ischemic function in normoxic hearts to values not different from hypoxic controls, but had no effect on hypoxic hearts. The nitric oxide synthase inhibitors L-NAME and L-NMA abolished the cardioprotective effect of hypoxia. Message and catalytic activity for constitutive nitric oxide synthase as well as nitrite, nitrate, and cGMP levels were elevated in hypoxic hearts. Inducible nitric oxide synthase was not detected in normoxic or chronically hypoxic hearts. Increased tolerance to ischemia in rabbit hearts adapted to chronic hypoxia is associated with increased expression of constitutive nitric oxide synthase.

Right ventricular function and exercise performance late after primary repair of tetralogy of Fallot with the transannular patch in infancy

To evaluate the late effects of chronic pulmonary regurgitation against the putative benefits from the current surgical trend of primary repair of tetralogy of Fallot with a transannular patch in infancy, 10 patients > 10 years after early primary repair and 7 matched normal controls underwent exercise stress test and cine magnetic resonance imaging assessment of ventricular functions. Right ventricular impaired diastolic function and decreased exercise capacity, both significantly associated with pulmonary regurgitation in patients, indicated that early primary repair of tetralogy may not prevent late ventricular dysfunction and diminished exercise performance if chronic regurgitation results from right ventricular outflow tract reconstruction.

Effect of repair strategy on hospital cost for infants with tetralogy of Fallot

OBJECTIVE

This study compares the total hospital cost (HC) for one-stage versus "two-stage" repair of tetralogy of Fallot (TOF) in infants younger than 1 year of age.

SUMMARY BACKGROUND DATA

Total (one-stage) correction of TOF is now being performed with excellent results in infancy. Alternatively, a two-stage approach, with palliation of infants in the first year of life, followed by complete repair at a later time can be used. In some institutions, the two-stage approach is standard practice for infants younger than 1 year of age or is used selectively in patients with an anomalous coronary artery across the right ventricular outflow tract (RVOT), "small pulmonary arteries," multiple congenital anomalies, critical illnesses (CI), which increase the risk of bypass (e.g., sepsis or DIC), or severe hypercyanotic spells (HS) at the time of presentation. The cost implications of these two approaches are unknown.

METHODS

The authors reviewed 22 patients younger than 1 year of age who underwent repair of TOF at their institution between 1993 and 1995. Eighteen patients had one-stage (1 degree) repair (mean age, 3.4 +/- 3.1 months; range, 3 days-9 months) and 4 patients were treated by a staged approach with initial palliation (1.6 +/- 0.4 month; range, 1.5-2 months) followed by later repair (14.75 +/- 1.5 months; range, 13-16 months). The reasons for palliation were severe HS at time of presentation (two patients), anomalous coronary artery (one patient) and CI (one patient). In the 18 patients undergoing 1 degree repair, 3 (16.6%) presented with HS, 6 (33.3%) had a transanular repair, and 6 (33.3%) were able to be repaired through an entirely transatrial approach (youngest patient, 1.5 months). The HC (1996 dollars) and hospital length of stay (LOS; days) were evaluated for all patients. The HCs were calculated using transition I, which is a cost accounting system used by our medical center since July 1992. Transition I provides complete data on all direct and indirect hospital-based, nonprofessional costs.

RESULTS

There was no mortality in either group. The group undergoing 1 degree repair had an average LOS of 14.5 +/- 11.2 days compared to an average LOS for palliation of 14 +/- 6.4 days. When the palliated group returned for complete repair, the average LOS was 28.8 +/- 25 days, yielding a total LOS for the two-stage strategy of 43 +/- 30.8 days (p = 0.003 compared to 1 degree repair). The HC for 1 degree repair was $32,541 +/- $15,968 compared to $25,737 +/- $1900 for palliation (p = not significant compared to 1 degree repair) and $54,058 +/- $39,395 for subsequent complete repair (p = not significant compared to 1 degree repair) (total two-stage repair HC = $79,795 +/- $40,625; p = 0.001 compared to 1 degree repair). The LOS and HC for the two-stage group combine a total of palliation plus later repair and, as such, reflect two separate hospitalizations and convalescent periods. To eliminate cost outliers, a best-case analysis was performed by eliminating 50% of patients from each group. Using this analysis, the two-stage approach resulted in an average (total) LOS of 16.5 +/- 2.1 days compared to 8.5 +/- 1.4 days for the 1 degree group. Total cost for the two-stage strategy in this best-case group was $44,660 +/- $3645 compared to $22,360 +/- $3331 for 1 degree repair (p = 0.00001).

CONCLUSIONS

The data from this review show that palliation alone generates HC similar to that from 1 degree infant repair of TOF, and total combined HC and LOS for palliation plus eventual repair of TOF (two-stage approach) are significantly higher than from 1 degree repair. Furthermore, these data do not include additional costs for care delivered between palliation and repair (e.g., outpatient visits, cardiac catheterization, serial echocardiography). Although there may be occasions when a strategy using initial palliation followed by later repair may seem prudent, the cost is clearly higher and use of health care resources greater.

Increased airway pressure and simulated branch pulmonary artery stenosis increase pulmonary regurgitation after repair of tetralogy of Fallot. Real-time analysis with a conductance catheter technique

BACKGROUND

Pulmonary regurgitation (PR) is an important determinant of outcome after repair of tetralogy of Fallot. Baseline PR was measured by magnetic resonance (MR) phase velocity mapping and from real-time right ventricular pressure-volume loops with a conductance catheter. Subsequently, the impact of two loading maneuvers (increased airway pressure, simulated branch pulmonary artery stenosis) on PR was assessed by the conductance catheter method.

METHODS AND RESULTS

Thirteen patients, 3 to 35 years after tetralogy of Fallot repair or pulmonary valvotomy, had PR measured by MR phase velocity mapping while breathing spontaneously. During catheterization under general anesthesia. PR was estimated from right ventricular pressure-volume loops generated by conductance and microtip pressure catheters. The effect of increased airway pressure (continuous positive airway pressure, 20 cm H2O; n = 12) and simulated branch pulmonary artery stenosis (transient balloon occlusion of a branch pulmonary artery, n = 7) was measured. Basal PR fraction derived by MR and from right ventricular pressure-volume loops had a correlation coefficient of .76 and mean of differences of 2.0 +/- 18.2% (95% limits of agreement). Increased airway pressure increased PR (16.3 +/- 11.4% to 25.7 +/- 17.3%, P < .01). Simulated branch pulmonary artery stenosis increased right ventricular end-systolic pressure (69.1 +/- 21.4 to 78.7 +/- 23.1 mm Hg, P < .05) and PR (27.5 +/- 11.3% to 36.9 +/- 12.8%, P < .05).

CONCLUSIONS

There was reasonable agreement between MR phase velocity-derived PR fraction and that obtained from right ventricular pressure-volume loops generated by use of conductance and pressure-microtip catheters. Exacerbation of PR by increased airway pressure and branch pulmonary stenosis may be relevant to the acute postoperative and long-term management, respectively, of patients after repair of tetralogy of Fallot.

Left and right ventricular volume characteristics in tetralogy of Fallot and their relationship to arterial oxygen saturation and age

Left (LV) and right ventricular (RV) volume characteristics in 43 patients with tetralogy of Fallot (TOF) undergoing no prior surgical intervention, aged 3-50 months, were evaluated. The control group consisted of 45 patients with Kawasaki disease without cardiac lesions, aged 12-82 months. The TOF patients were divided into four groups: those having arterial oxygen saturation < 80% with an age at the time of study < 18 months (group 1a) or with that > or = 18 months (group 1b), and those with arterial oxygen saturation > or = 80% with an age < 18 months (group 2a) or with that > or = 18 months (group 2b). The results were compared with those in control subjects. In group 1a, each of LV end-diastolic volume (EDV), LV ejection fraction (EF), RVEDV and RVEF was reduced. In group 1b, LVEDV, LVEF and RVEF were decreased. In groups 2a and 2b, RVEF alone was depressed. From these results, the severity of hypoxemia was an important risk factor for ventricular dysfunctions. No influence of age on the volume characteristics was found. The investigations suggested that patients with TOF having an arterial oxygen saturation < 80% are probably candidates for early surgical intervention.

Oxidative insult associated with hyperoxic cardiopulmonary bypass in the infantile heart and lung

Cardiopulmonary bypass (CPB) per se alters many factors simultaneously, including free radical generation, which suggests that conventional hyperoxic CPB may produce oxidative injury in the infantile heart and lung. This study tests the hypothesis that CPB provokes oxidative cardiopulmonary changes and pulmonary endothelial dysfunction in immature piglets that can be prevented by free radical scavengers. We studied 15 2- to 3-week-old piglets. Five served as a control without CPB. Ten piglets underwent 60 min of CPB with a membrane oxygenator (Sarns). In 5 of these 10, the bypass prime was supplemented with N-mercaptopropionylglycine (MPG: 80 mg/kg) plus catalase (50,000 U/kg), whereas the others were not treated. Pre- and post-bypass cardiopulmonary function was measured in terms of left ventricular end-systolic elastance [Ees] by a conductance catheter, the arterial/alveolar pO2 ratio (a/A ratio) and static lung compliance. Conjugated dienes (A233 nm/mg lipid) were measured to detect lipid peroxidation in heart and lung tissue, and myocardial antioxidant reserve capacity [malondialdehyde (MDA) production in cardiac tissue incubated with the oxidant t-butyl hydroperoxide (t-BHP)] was assessed to detect oxidative changes. Pulmonary vascular resistance (PVR) and transpulmonary nitric oxide (NO) production were measured to assess pulmonary endothelial injury. Myocardial antioxidant reserve capacity was significantly reduced after 60 min of CPB, compared to control animals (MDA 779 +/- 100 vs 470 +/- 30 nmol/g protein, p < 0.05 at t-BHP 2.0 mmol/L), without evidence of lipid peroxidation or myocardial dysfunction. Pulmonary vascular resistance after CPB was dramatically increased (83 +/- 12 to 212 +/- 30, p < 0.05) without any change in lung function. In parallel to pulmonary vasoconstriction, NO production was significantly decreased after CPB (from 8.8 +/- 1.4 to 2.5 +/- 0.5 mmol/min/kg, p < 0.05). The addition of antioxidants (MPG+catalase) to the prime significantly improved myocardial antioxidant status (MDA: 604 +/- 30 vs 779 +/- 100 nmol/g protein, p < 0.05) and pulmonary vascular resistance (114 +/- 29 vs 212 +/- 30, p < 0.05 vs no-treatment group). In conclusion, the present study confirms that 1) Cardiopulmonary bypass produces substantial oxidative stress in normal immature myocardium, as assessed by reduced antioxidant reserve capacity; 2) CPB impairs pulmonary endothelial function, characterized by NO production, resulting in pulmonary vasoconstriction; and 3) These deleterious effects can be prevented by the addition of antioxidants (MPG/catalase) to the pump prime.

Routine primary repair of tetralogy of Fallot in neonates and infants less than three months of age

BACKGROUND

Although primary repair of tetralogy of Fallot is increasingly undertaken in infancy, complete repair is generally performed in only selected symptomatic neonates.

METHODS

From July 1992 through March 1995, 30 consecutive neonates and young infants with tetralogy of Fallot underwent routine primary repair. Group I (n = 10) consisted of patients with tetralogy of Fallot and pulmonary atresia (n = 5) or severe pulmonary stenosis (n = 5) who were duct dependent and were repaired in the neonatal period. Group II (n = 11) consisted of patients who were asymptomatic with arterial oxygen saturation between 75% and 90% (adequate pulmonary blood flow). Group III (n = 9) consisted of patients with "pink" tetralogy of Fallot (arterial oxygen saturation > 90%). Patients in groups II and III were electively scheduled for repair at about 2 months of age.

RESULTS

The postrepair peak systolic right ventricular-to-peak systolic left ventricular pressure ratio did not correlate (p = 0.96) with the branch pulmonary artery size. One patient died 2 months after operation, despite good hemodynamics, of uncontrollable diffuse subcutaneous edema due to familial distichiasis lymphedema syndrome. There were no late deaths. At a median follow-up of 19 months, 1 patient underwent balloon dilation of branch pulmonary arteries. Follow-up echocardiography revealed a 30 to 60 mm Hg right ventricle-to-pulmonary artery gradient in 3 patients.

CONCLUSIONS

Excellent early and midterm results can be accomplished with routine primary repair of tetralogy of Fallot in early infancy regardless of age, symptomatic status, coronary anatomy, and the size of branch pulmonary arteries as long as they arborize normally.

Studies of hypoxemic/reoxygenation injury: without aortic clamping. VII. Counteraction of oxidant damage by exogenous antioxidants: coenzyme Q10

Coenzyme Q10 (CoQ10) is a natural mitochondrial respiratory chain constituent with antioxidant properties. This study tests the hypothesis that CoQ10 administered before the onset of reoxygenation on cardiopulmonary bypass, can reduce oxygen-mediated myocardial injury and avoid myocardial dysfunction after cardiopulmonary bypass. The antioxidant properties of CoQ10 were confirmed by an in vitro study in which normal myocardial homogenates were incubated with the oxidant, t-butylhydroperoxide. Fifteen immature piglets (< 3 weeks old) were placed on 60 minutes of cardiopulmonary bypass. Five piglets underwent cardiopulmonary bypass without hypoxemia (oxygen tension about 400 mm Hg). Ten others became hypoxemic on cardiopulmonary bypass for 30 minutes by lowering oxygen tension to approximately 25 mm Hg, followed by reoxygenation at oxygen tension about 400 mm Hg for 30 minutes. In five piglets, CoQ10 (45 mg/kg) was added to the cardiopulmonary bypass circuit 15 minutes before reoxygenation, and five others were not treated (no treatment). Myocardial function after cardiopulmonary bypass was evaluated from end-systolic elastance (conductance catheter), oxidant damage (lipid peroxidation) was assessed by measuring conjugated diene levels in coronary sinus blood, and antioxidant reserve capacity was determined by measuring malondialdehyde in myocardium after cardiopulmonary bypass incubated in the oxidant, t-butylhydroperoxide. Cardiopulmonary bypass without hypoxemia caused no oxidant damage and allowed complete functional recovery. Reoxygenated hearts (no treatment) showed a progressive increase in conjugated diene levels in coronary sinus blood after reoxygenation (2.3 +/- 0.6 A233 nm/0.5 ml plasma at 30 minutes after reoxygenation) and reduced antioxidant reserve capacity (malondialdehyde: 1219 +/- 157 nmol/g protein at 4.0 mmol/L t-butylhydroperoxide), resulting in severe postbypass dysfunction (percent end-systolic elastance = 38 +/- 6). Conversely, CoQ10 treatment avoided the increase in conjugated diene levels (2.1 +/- 0.6 vs 1.1 +/- 0.3, p < 0.05 vs no treatment), retained normal antioxidant reserve (896 +/- 76 nmol/g protein, p < 0.05 vs no treatment), and allowed nearly complete recovery of function (94% +/- 7%, p < 0.05 vs no treatment). We conclude that reoxygenation of the hypoxemic immature heart on cardiopulmonary bypass causes oxygen-mediated myocardial injury, which can be limited by CoQ10 treatment before reoxygenation. These findings imply that coenzyme Q10 can be used to surgical advantage in cyanotic patients, because therapeutic blood levels can be achieved by preoperative oral administration of this approved drug.

Quantitative morphometric analysis of progressive infundibular obstruction in tetralogy of Fallot. A prospective longitudinal echocardiographic study

BACKGROUND

The morphological hallmark of tetralogy of Fallot is controversial, with much disagreement as to whether the subpulmonary infundibulum in this lesion is hypoplastic. In addition, few quantitative data are available regarding the morphometry of the subpulmonary infundibulum, what anatomic characteristics are acquired in the postnatal period, and at what rate they progress. We also sought to determine whether echocardiographic morphometric analysis of the infundibulum can predict clinical course in infants with tetralogy of Fallot.

METHODS AND RESULTS

Twenty-one infants with tetralogy of Fallot (median age at initial study, 1.6 months) were prospectively followed with serial echocardiograms until the time of first surgical intervention (median age at surgery, 10 months). Selected video still frames were digitized off-line with a computerized system. Compared with age-matched normal control infants (n = 37), the following indexed infundibular dimensions in patients with tetralogy of Fallot were significantly smaller: length (1.86 +/- 0.54 versus 2.7 +/- 0.56 cm/BSA0.5, P < .0001), cross-sectional area (1.6 +/- 0.49 versus 4.7 +/- 1.3 cm2/BSA, P < .0001), and volume (1.24 +/- 0.62 versus 7.2 +/- 3 mL/BSA1.5, P < .0001). The following measurements were increased in tetralogy patients: infundibular septal thickness (0.83 +/- 0.21 versus 0.54 +/- 0.06 cm/BSA0.5, P = .0002) and infundibular free-wall thickness (0.62 +/- 0.13 versus 0.49 +/- 0.06 cm/BSA0.5, P = .006). The angle between infundibular septum and ventricular septum had a greater degree of anterosuperior deviation in tetralogy patients, resulting in a larger infundibuloventricular septal angle (77 +/- 8.2 degrees versus 31 +/- 6.5 degrees, P < .0001). During follow-up, infundibular volume in tetralogy patients decreased from 1.24 +/- 0.62 to 0.81 +/- 0.47 mL/BSA1.5 (P = .002), correlating with infundibular septal thickness (r = -.63, P < .003). The mean rate of decrease of indexed infundibular volume was 0.1 +/- 0.13 mL.BSA-15.mo-1. Correlation analysis revealed a nonlinear correlation between the degree of infundibular septal malalignment and indexed infundibular volume (r = .93, P < .0001). Tetralogy patients who required early surgical intervention (4.8 +/- 0.9 versus 10.7 +/- 1.7 months, P < .0001) had a smaller infundibulum at presentation (0.92 +/- 0.35 versus 1.41 +/- 0.67 mL/BSA1.5, P = .04) and an accelerated rate of infundibular narrowing (0.17 +/- 0.18 versus 0.06 +/- 0.08 mL.BSA-1.5.mo-1, P = .04).

CONCLUSIONS

Compared with normal infants, the subpulmonary infundibulum in tetralogy of Fallot is characterized by a smaller volume, shorter and thicker infundibular septum, and anterosuperior deviation of the infundibular septum. Infundibular obstruction in tetralogy patients is progressive, with an average rate of decrease in indexed infundibular volume of 0.1 +/- 0.13 mL.BSA-1.5.mo-1. Infants who are likely to require early therapeutic intervention may be identified on their initial echocardiogram as having an infundibular volume of < 0.9 to 1.0 mL/BSA1.5.

Experimental ablation of outflow tract muscle with a thermal balloon catheter

BACKGROUND

Pulmonary balloon valvuloplasty has been performed in selected patients with tetralogy of Fallot as an alternative to surgical palliation; this technique is limited, however, by the fact that the balloon has little effect on the dynamic, muscular contribution to outflow tract obstruction. In an experimental model, we used a new thermal balloon catheter to ablate right ventricular outflow tract muscle. We evaluated the acute efficacy and muscle ablation parameters of this technology and its effects after myocardial healing.

METHODS AND RESULTS

A prototype electrolyte-filled balloon catheter, heated by radiofrequency energy, was constructed. Studies were conducted to determine the optimum electrolyte solution needed to minimize balloon heating time with an unmodified, commercially available radiofrequency generator. In vivo ablations of right ventricular outflow tract muscle with the thermal balloon were performed in lambs that were divided into three groups (n = 5 each) according to the duration of thermal energy delivery (20, 40, and 60 seconds, respectively). Ablated lesion volume increased (460 +/- 63 to 1156 +/- 256 mm3) as the energy delivery time increased (20 to 60 seconds) and was correlated with delivered energy, temperature integral, and maximum epicardial surface temperature (r = .85, .82, and .72, respectively). All five lesions in the 60-second group showed an acute decrease of the wall thickness. Additional in vivo ablations were performed in 6 animals in which survival studies showed muscle thinning, healing by fibrosis, and no evidence of aneurysm formation.

CONCLUSIONS

Thermal energy can be used with a balloon catheter delivery system to ablate myocardium. This study suggests that this energy delivery technology might be useful for relief of muscular outflow tract obstruction and that further studies are warranted.

Early balloon dilatation of the pulmonary valve in infants with tetralogy of Fallot. Risks and benefits

BACKGROUND

Balloon dilatation, an established treatment for pulmonary valve stenosis, remains a controversial procedure in tetralogy of Fallot.

METHODS AND RESULTS

Balloon dilatation of the pulmonary valve was performed in 19 infants with tetralogy of Fallot. Its effects on the severity of cyanosis, the growth of the pulmonary valve and pulmonary arteries, and the need for transannular patching were evaluated. Clinical, echographic, angiographic, hemodynamic, and operative data were analyzed. The procedure was safe in all, without significant complications. After balloon dilatation, systemic oxygen saturation increased from a mean value of 79% to 90%. This increase proved to be short-lasting in 4 patients, who required surgery before the age of 6 months. Balloon dilatation increased pulmonary annulus size in each case, from a mean value of 4.9 to 6.9 mm (P < .001). This gain in size remained stable over time, with a mean Z score of -4.8 SD before dilatation, -3.1 SD immediately after the procedure, and -2.7 SD at preoperative catheterization (P < .001). Pulmonary artery dimensions remained unchanged immediately after balloon dilatation but increased at follow-up from a Z score mean value of -2.5 to -0.06 SD and from -2.2 to 0.04 SD for right and left pulmonary arteries, respectively (P < .001). At the time of corrective surgery, the pulmonary annulus was considered large enough to avoid a transannular patch in 69% of the infants. This represented a 30% to 40% reduction in the need for a transannular patch compared with the incidence of transannular patch expected before balloon dilatation.

CONCLUSIONS

Pulmonary valve dilatation in infants with tetralogy of Fallot is a relatively safe procedure and appears to produce adequate palliation in most patients. It allowed the growth of the pulmonary annulus and of the pulmonary arteries, resulting in a mean gain of 2 SD for those structures.