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J Thorac Cardiovasc Surg 2003;126:703-710
© 2003 The American Association for Thoracic Surgery
Surgery for congenital heart disease |
a Department of Critical Care Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
b Division of Cardiology, The Hospital for Sick Children, Toronto, Ontario, Canada
c Division of Cardiovascular Surgery,The Hospital for Sick Children, Toronto, Ontario, Canada, Canada
Received for publication June 18, 2002; revisions received July 22, 2002; revisions received August 7, 2002; accepted for publication August 27, 2002.
* Address for reprints: Dr Desmond Bohn, The Department of Critical Care Medicine, The Hospital for Sick Children, Toronto, Ontario, M5G 1X8 Canada, USA
dbohn{at}sickkids.on.ca
| Abstract |
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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 Coxs 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.
At the Hospital for Sick Children, the surgical approach to the management of tetralogy has evolved over the past decade from the traditional palliation and later correction to one of primary repair in the first few months of life. The current institutional policy is now elective repair at 6 months for those infants who are not having cyanotic spells and repair rather than shunting for spelling infants less than 6 months of age. We have previously published our experience in the management of patients with TOF (years 1987-1994) who were less than 18 months of age at the time of surgical repair. That study, in which the median age at repair was 13 months, focused on perioperative issues that might impact on clearly defined short-term outcomes and showed that younger age at repair and previous palliation were correlated with increased intensive care unit (ICU) length of stay.20 However, only 9/89 patients were less than 6 months of age at the time of repair. We have undertaken a second study to evaluate impact of a change in institutional policy that evolved between 1994 and 1997 to earlier correction in the first few months of life. We focused our review on the early postoperative morbidity and mortality.
| Methods |
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In the period of study, 81 patients were identified. Hemodynamic data were missing on 3 patients, so the study group consisted of 78 patients, of whom 41 were female (53%) and 37 were male (47%). The median age at repair was 8 months (range, 36 days18.5 months) with a median weight of 7.2 kg (range, 2.8-12). The spectrum of age ranges were less than 3 months (n = 12), 3 to less than 6 months (n = 20), 6 to less than 9 months (n = 21), and older than 9 months (n = 25).
Preoperative data
Anatomical characteristics such as main and branch pulmonary artery (PA) stenosis, additional VSDs, patent foramen ovales (PFOs), and ASDs, systemic to pulmonary collaterals, and coronary arterial abnormalities were defined by preoperative echocardiography. Furthermore, it was noted if patients were cyanotic or were receiving propranolol. The presence of other cardiac and noncardiac abnormalities was also noted.
Operative characteristics
The following details of the surgical repair were documented; the approach to the repair of the VSD and the RV outflow tract obstruction, whether the pulmonary valve was spared from disruption or a transannular patch with or without a pericardial monocusp valve was used and whether a PA arterioplasty was done. The cardiopulmonary bypass time and aortic crossclamp time were also recorded. Data were also collected on intraoperative hemodynamic pressure and saturation measurements as well as the findings on intraoperative echocardiography.
Postoperative ICU data
Data were collected on the ICU length of stay, duration of mechanical ventilation, and complications including arrhythmias, chest radiograph changes, infections, and diaphragmatic paresis. Patients are generally discharged from the ICU the day following extubation. In order to quantify the postoperative morbidity in terms of extrathoracic organ dysfunction, a pediatric modification of the multiple organ dysfunction syndrome (MODS) score was used.21 This quantifies the failure of the main organ systems by means of age-adjusted criteria, which are based on clinical or laboratory measurements and supportive therapies (Table 1).
Criteria for an infection were the presence of elevated white blood cell count, a positive culture and clinical symptoms including fever above 38.5°C.
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Data analysis
Data are described as frequencies, medians with ranges, and means with standard deviations. Where there are missing data, the number of nonmissing values is given. Time to discharge from the ICU was represented by Kaplan-Meier estimates. Independent factors associated with time to ICU discharge were sought using Coxs proportionate hazard modeling. In addition, independent factors associated with an ICU stay of more than 2 days were sought in multiple logistic regression analysis. After a normalizing transformation (natural logarithm), independent factors associated with duration of mechanical ventilation were sought in general linear regression modeling. Trends related to age were sought by categorizing age at repair into 4 groups: <3 months, 3 to 5 months, 6 to 8 months, and 10 to 18 months. Age-related trends in preoperative and operative characteristics were sought with
2, Mantel- Haenszel
2, analysis of variance, and Kruskal-Wallis analysis of variance as appropriate. The relationships to age at repair and postoperative time to hemodynamic parameters were sought in mixed linear regression analysis for repeated measures. All analyses were performed using SAS Version 7 statistical software (SAS Institute, Inc., Cary, NC) with default settings except where indicated.
| Results |
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Apart from the typical features of tetralogy, the significant preoperative echocardiographic findings were systemic to pulmonary artery collaterals in 20 patients (26%) and coronary arterial abnormalities in 10 patients (13%). These consisted of the presence of an accessory left anterior descending coronary artery from the right coronary artery in 9 cases and 1 case of a coronary fistula. Associated intrathoracic vascular abnormalities were noted in 27 patients (35%), including right aortic arch in 22 patients, left superior vena cava to coronary sinus drainage in 4, and aberrant subclavian artery in 4. Chromosomal abnormalities and malformation syndromes were found in 17 patients (22%). These included 6 patients with Down syndrome, 3 patients with diGeorge syndrome, 2 patients with VACTER(L)* association, and 1 patient with CHARGE
association.
Operative characteristics
The operative approach to closure of the VSD (n = 76) was through the atrium in 67 patients (88%) and through a ventriculotomy in 9 (12%). The RV outflow tract was repaired by the transatrial approach in 9 patients (12%), via a transatrial-transpulmonary approach in 62 (79%), through the ventricular infundibulum in 53 (68%), and through the pulmonary valve annulus in 22 patients (28%). Sometimes different approaches were combined in the same patient. The pulmonary valve was spared (not disrupted) during repair in 50 patients (64%), a transannular patch was used in 15 (19%), and a transannular patch with placement of a pericardial monocusp valve was used in 13 patients (17%). A PA arterioplasty was performed in 72 patients (92%). The PFO or ASD was closed in 56 (72%) and surgically restricted in 15 patients (19%).
Intraoperative pressure and saturation measurements were performed before sternal closure. The median of the difference between the RV and main PA systolic pressures was 15 mm Hg (range, 0-40; n = 63), the mean RV to LV systolic pressure ratio was 0.48 ± 0.11 (n = 62), and the median main PA to RA percent oxygen saturation ratio was 1.01 (range, 0.88-1.16; n = 37). Intraoperative transesophageal echocardiography was performed after repair in 71 patients (91%). Mild PI was found in 18 (25%) and moderate in 13 patients (18%). Pulmonary insufficiency was trivial or unremarkable in the remaining 57%. In 8 patients (11%) the presence of a residual VSD was noted, but none required further repair. The median RV outflow tract gradient was 19 mm Hg (range, 0-45, n = 66). All patients had modified ultrafiltration performed at the end of bypass.
Postoperative ICU data
The median ICU length of stay was 2 days (range, 1-14), and the median mechanical ventilation time was 16.2 hours (range, 0-10.7 days), 1 patient being extubated in the operating room. In 2 patients, the sternum was left open at the end of the procedure and 4 additional patients had the sternum reopened for bleeding or because of myocardial edema (4 patients <3 months and 2 >3 months). Arrhythmias occurred in 19 patients (24%), of whom 6 had junctional ectopic tachycardia and there was 1 patient with complete atrioventricular block. Temporary cardiac pacing was performed in 13 patients (17%).
Chest radiograph abnormalities were noted in 57 patients (73%); 43 with pleural effusion (75%), and 38 with some degree of pulmonary atelectasis (67%). Diaphragmatic paresis was noted in 1 patient (1%). Reduced glucose levels were noted in 16 patients (21%). None of the patients required renal replacement therapy. Six patients (8%) were diagnosed with an infection, 3 with sepsis, 2 with mediastinitis, and 1 with a urinary tract infection.
Using the MODS criteria, as defined as dysfunction of 2 or more organ systems, which extended beyond 48 hours, was noted in 9 patients. Of these, 1 patient had dysfunction of 2 organs and 8 patients had dysfunction of 3 or 4 organs. All went on to make a full recovery. Intravenous dopamine was used in 65 patients (83%) after the first hour, in 31 patients (49%) after 24 hours, and in 12 patients (41%) after 48 hours ICU admission. At the same time points, intravenous amrinone or milrinone was used in 7 (9%), 15 (24%), and 12 patients (41%), respectively. Intravenous epinephrine was used in 2 (3%), 5 (8%), and 5 patients (17%) at these time points. Intravenous sodium nitroprusside was used in 62 patients (79%) after 1 hour, to 25 patients (40%) after 24 hours, and to 12 (41%) after 48 hours ICU admission.
Death or reintervention within 30 days
There were no deaths during the postoperative hospital stay. However, 1 patient was known to have died following discharge from the hospital, 21 days after repair. The cause of death was cardiac tamponade associated with noninfective pericarditis and an effusion (postpericardiotomy syndrome). No patient required reintervention within 30 days of operation. Five patients underwent cardiac catheterization with stenting or dilatation of the RV outflow tract or pulmonary arteries, all more than 6 months after surgery.
Relationship of perioperative characteristics to age at repair
Differences between age groups regarding preoperative characteristics are given in Table 2.
There were no age-related differences regarding any cardiac anomalies. However, younger patients were significantly more likely to have extracardiac anomalies.
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| Discussion |
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The publication of our previous outcome study of tetralogy patients,20 which also focused on the immediate morbidity associated with repair at a somewhat older age, allows us to make some interesting comparisons (Table 6). In our previously reported series, 24% of patients had a prior shunt and there were 6 (7%) deaths within the first 48 hours of surgery. The median age at repair is lower in the current series (8 vs 13 months) and the proportion of patients less than 6 months of age at repair is higher (41% vs 10%). In our current series, 70% of patients were discharged from ICU within 2 days compared with 20% previously. The median duration of ventilation was 16 hours compared with 74 hours in 1987 to 1994. This may be accounted for partially by a change in management philosophy to one of early extubation, which has evolved based on studies showing the adverse effect of positive pressure ventilation in patients with tetralogy and restrictive RV physiology.23,24 The incidence of JET, one of the most hemodynamically significant arrhythmias, has previously been reported to be increased with younger age at repair.9,25 We did not find this and, more particularly, the occurrence rate (8%) in our recent series is less than we reported previously (20%). Despite reports of more frequent use of outflow tract patches in young infants,13 there is a trend at our institution towards a decreasing use of a transannular patch with more frequent sparing of the pulmonary valve and more frequent use of PA arterioplasty.15,20
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| Conclusions and study limitations |
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| Footnotes |
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Coloboma, heart disease, atresia choanae, retarded growth, genito-urinary abnormalities, and ear anomalies. ![]()
| References |
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