BACKGROUND: Despite the advances in the surgical treatment of Tetralogy of Fallot(TOF), pulmonary regurgitation (PR) remains as a possible complication with detrimental impact on right ventricular function (RV) in the long term. If these effects are not reversed timeously by replacing the pulmonary valve, serious morbidity and even mortality may occur. AIM: The aim of the study was to assess the outcomes in children who had complete repair of TOF at Charlotte Maxeke Johannesburg Academic Hospital (CMJAH) with or without a RV outflow conduit with emphasis on the development of PR, as well as signs and symptoms that could be linked to PR. METHOD: A retrospective clinical audit on patients with a diagnosis of TOF and who had surgery at the CMJAH between 01/01/1994 and 31/12/2003 was undertaken. Data collected and entered onto a data collection sheet included ethnicity, sex, type of surgery which was either palliation with a Blalock-Taussig shunt (BTS) or corrective surgery, age at surgery, echocardiographic documentation of PR and RV size during follow-up. Other information included electrocardiogram (ECG) changes, abnormalities detected on chest X-ray (CXR), whether or not the patient was subjected to re-operation, as well as the indications of re-operation. RESULTS: Of the 72 patients with TOF and available data, fifty four patients (75%) had surgery, 50 (92.6%) of whom had corrective surgery and 4(7.4%) had palliative surgery in the form of a BTS only. Of the 50 who had corrective surgery, 2 (4%) patients had an initial BTS shunt while the remaining forty eight (96%) underwent initial primary corrective surgery. There were 46 males (63.9%) and 26 (36.1%) females. The median age at first visit was 13 months (range, 0.03 to 177), median age at corrective repair was 39.5 months (range, 3 to 210) and median age at palliation was 18 months (range, 1.5 to 29). Of the 50 patients undergoing corrective surgery, 60% had complex anatomy and 40% simple anatomy. More females compared to males had complex anatomy with a hypoplastic pulmonary valve (p= 0.047). Two patients undergoing a transannular patch (TAP) developed severe PR in the immediate postoperative period (less than 1 year) whilst no patients in the simple repair group developed severe PR (p= 0.110). In the intermediate postoperative period (1 to 5 years), there was 1 patient each in the TAP and simple repair group with severe PR (p = 0.476). Finally in the long term period (more than 5 years), 8 patients with TAP developed severe PR whilst 2 patients with simple repair developed severe PR (p= 0.005). Two patients out of fifteen patients (13.3%) with TAP had a pulmonary valve replacement (PVR). No patients with simple repair had PVR. CONCLUSION: Severe PR is an expected and serious complication accompanying all forms of repair techniques employed for the wide anatomical spectrum of TOF. In this study, comparison of the two most common types of repair, namely simple versus TAP, revealed a statistically significant occurrence of PR in the TAP group. Appropriate timing for PVR is paramount for the symptomatic patients in order to preserve RV function.

Thesis (M. Med. Sc.)--University of Hong Kong, 2004. / Also available in print.

No description available.

published_or_final_version / Medical Sciences / Master / Master of Medical Sciences

An abnormal chronotropic response to exercise is a common finding following surgical repair of tetralogy of Fallot (TOF) which has generally been attributed to a putative sympathetic dysfunction. There exists little information on sympathetic function in patients operated for a congenital heart defect to support such a claim. This study used spectral analysis of heart rate (HRV) and blood pressure (BPV) variability to examine sympathovagal influences on the sinus node in 9 adolescents operated for TOF 13.0 +/- 1.12 years previously and in 8 healthy age and sex-matched control (CTRL) subjects. Continuous ECG and BP recordings were obtained under supine or seated resting positions, with or without controlled respiration at 0.20 Hz (CR); after passive 85° head-up tilt (HUT); during cycling at steady-state heart rates of 100 and 120 bpm (Ex 100, Ex 120), and after 10 and 20 minutes of passive seated recovery. (Abstract shortened by UMI.)

Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart defect and infants with TOF incur significant right ventricular(RV) dysfunction due to perioperative injury. Insulin has been shown to reduce perioperative myocardial injury and significantly improve postoperative cardiac function. However, studies are limited to the adult population and the effects in a pediatric heart with a CHD are unknown. To the best of our knowledge, this is the first randomized, double blind, placebo-controlled clinical study designed to investigate insulin’s potential cardioprotective effects postoperatively and mechanisms of action during pediatric cardiac surgery. Thirty infants with TOF were equally randomly allocated to receive either standard cardioplegia (SC) or 10UI insulin-enhanced (IC). Expression profiles of surgery were generated from biopsies extracted from the right ventricular outflow tract (end ischemia and five minutes of reperfusion) and hybridized to Affymetrix HG-U133A GeneChips. Gene expression profiles were generated using two softwares, ArrayAssist V2.6 (paired t-test) and affylmGUI (ANOVA). Survival rate was 100%. Compared to patients in the SC group, patients in the IC group demonstrated a trend toward a 1.8 fold decrease (p = .06) in reperfusion duration (61.93 ± 61.12 vs. 35.20 ± 23.16 hrs., respectively), a significant 2-fold decrease in the length of ICU stay (p = .04) (4.2 ± 3.9 vs. 2.3 ± 1.1 days, respectively) and a trend toward a 2.5 fold decrease in intubation duration (p= .06) (2.5± 12.2 vs. 55.0 ± 67 hrs., respectively). Patients in the IC group also demonstrated significantly lower inotropic scores, calculated at 12-hour intervals across a 48-hour ICU period, (ANOVA p = .01) and significantly greater urine volume, by 71%, (p = .02). IC evoked a cardioprotective gene expression profile aimed at mitigating perioperative myocardial injury, specifically; apoptosis, inflammation, cardiac hypertrophy, arrythmias and fibrosis. The improved postoperative outcome and cardioprotective gene expression signature with IC suggests that, administration of insulin during cardiac surgery in infants with TOF may prevent cardiac dysfunction as a result of mitigating perioperative myocardial injury. Overall, this exploratory study demonstrated insulin-enhanced cardioplegia to be a potential cardioprotective agent during pediatric heart surgery.

Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart defect and infants with TOF incur significant right ventricular(RV) dysfunction due to perioperative injury. Insulin has been shown to reduce perioperative myocardial injury and significantly improve postoperative cardiac function. However, studies are limited to the adult population and the effects in a pediatric heart with a CHD are unknown. To the best of our knowledge, this is the first randomized, double blind, placebo-controlled clinical study designed to investigate insulin’s potential cardioprotective effects postoperatively and mechanisms of action during pediatric cardiac surgery. Thirty infants with TOF were equally randomly allocated to receive either standard cardioplegia (SC) or 10UI insulin-enhanced (IC). Expression profiles of surgery were generated from biopsies extracted from the right ventricular outflow tract (end ischemia and five minutes of reperfusion) and hybridized to Affymetrix HG-U133A GeneChips. Gene expression profiles were generated using two softwares, ArrayAssist V2.6 (paired t-test) and affylmGUI (ANOVA). Survival rate was 100%. Compared to patients in the SC group, patients in the IC group demonstrated a trend toward a 1.8 fold decrease (p = .06) in reperfusion duration (61.93 ± 61.12 vs. 35.20 ± 23.16 hrs., respectively), a significant 2-fold decrease in the length of ICU stay (p = .04) (4.2 ± 3.9 vs. 2.3 ± 1.1 days, respectively) and a trend toward a 2.5 fold decrease in intubation duration (p= .06) (2.5± 12.2 vs. 55.0 ± 67 hrs., respectively). Patients in the IC group also demonstrated significantly lower inotropic scores, calculated at 12-hour intervals across a 48-hour ICU period, (ANOVA p = .01) and significantly greater urine volume, by 71%, (p = .02). IC evoked a cardioprotective gene expression profile aimed at mitigating perioperative myocardial injury, specifically; apoptosis, inflammation, cardiac hypertrophy, arrythmias and fibrosis. The improved postoperative outcome and cardioprotective gene expression signature with IC suggests that, administration of insulin during cardiac surgery in infants with TOF may prevent cardiac dysfunction as a result of mitigating perioperative myocardial injury. Overall, this exploratory study demonstrated insulin-enhanced cardioplegia to be a potential cardioprotective agent during pediatric heart surgery.

No description available.

Thesis (M. Med. Sc.)--University of Hong Kong, 2005.

Tetralogy of Fallot (TOF) is the most common cyanotic congenital cardiac defect with a global annual incidence of 40,000 cases. Advances in surgery and perioperative care led to improvements in perioperative mortality and, thus, a growing number of survivors. TOF survivors often suffer from complications related to a failing right ventricle. Follow-up studies evaluating TOF repair strategies suggest an association between the type of surgical repair strategy and late right ventricular health. However, surgical practices remain unchanged and led by institution-level biases. The body of evidence addressing outcomes based on TOF surgical repair strategy is weak and controversies persists on the management of these patients.  This thesis comprises 6 chapters that form the foundation of a multi-centre research program on outcomes after TOF surgical repair. The program uses various methodologies to generate evidence with a vision to change surgical practices.  Chapter 1 is an introduction providing background on TOF and contemporary areas of controversy.  Chapter 2 presents the results of a retrospective analysis evaluating the use of early echocardiogram parameters in predicting late cardiac magnetic resonance imaging evaluation of the right ventricle.  Chapter 3 presents the results of a retrospective cohort exploring the association between TOF repair strategy and development of right bundle branch block.  Chapter 4 presents the results of a multinational survey aiming to explore contemporary biases in TOF surgical repair strategy selection.  Chapter 5 presents the background, rationale, design and baseline cohort characteristics of the Tetralogy of Fallot for Life (TOF LIFE) study. The study is a multi-centre inception cohort study with a follow-up period of 2 years.  Finally, Chapter 6 discusses the conclusion, limitations, and future implications of this research program. / Thesis / Doctor of Science (PhD)