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Biomedical subjects

Thomas L Spray

Publications and source records attributed to Thomas L Spray.

At least 37 records · Page 2Linked to original sources
PubMed2005

Outcomes after the stage I reconstruction comparing the right ventricular to pulmonary artery conduit with the modified Blalock Taussig shunt.

BACKGROUND: Recent reports advocate that a right ventricular to pulmonary artery (RV-PA) conduit improves outcome after the stage I reconstruction. METHODS: We retrospectively compared the outcomes of all neonates who underwent a stage I reconstruction between January 1, 2002, and October 1, 2004, with use of the RV-PA conduit and modified Blalock-Taussig shunt (mBTS) interspersed over this time period. RESULTS: In all, 149 infants underwent a stage I reconstruction (95 mBTS, 54 RV-PA) for hypoplastic left heart syndrome (HLHS) or variants. There was a preference for the RV-PA conduit in patients with aortic atresia (mBTS 30% versus RV-PA 67%, p < 0.01). There was no difference in surgical mortality (mBTS 14% versus RV-PA 17%, p = 0.67), time to extubation (mBTS 4.5 +/- 4.8 days versus RV-PA 3.9 +/- 3.5 days, p = 0.47), or length of hospital stay (mBTS 25 +/- 29 days versus RV-PA 21 +/- 23 days, p = 0.52). There was an increased incidence of shunt reinterventions in the patients with the RV-PA conduit (mBTS 17% versus RV-PA 32%, p = 0.04). Patients with RV-PA conduit returned earlier for stage II reconstruction (mBTS 6.5 +/- 2.5 months versus RV-PA 5.6 +/- 1.7 months, p = 0.05). There was no difference in overall mortality (mBTS 32% versus RV-PA 30%, p = 0.45) with a median duration of follow-up of 18 +/- 8 months. CONCLUSIONS: Comparing shunt strategies (mBTS versus RV-PA) over the same time period, we found no difference in outcome. These data support the need for a larger prospective, randomized trial.

Arteriovenous Shunt, Surgical↗
PubMed2005

Current status of the European Association for Cardio-Thoracic Surgery and the Society of Thoracic Surgeons Congenital Heart Surgery Database.

BACKGROUND: After utilizing separate congenital databases in the early 1990s, the Society of Thoracic Surgeons (STS) and the European Association for Cardio-Thoracic Surgery (EACTS) collaborated on several joint database initiatives. METHODS: In 1998, the joint EACTS-STS International Congenital Heart Surgery Nomenclature and Database Project Committee was created and a common nomenclature and common core minimum database dataset were adopted and published by the STS and the EACTS. In 1999, the joint EACTS-STS Aristotle Committee was created and the Aristotle Score was adopted and published as a method to provide complexity adjustment for congenital heart surgery. Collaborative efforts involving the EACTS and STS are underway to develop mechanisms to verify data completeness and accuracy. RESULTS: Since 1998, this nomenclature, database, and methodology of complexity adjustment have been used by both the STS and EACTS to analyze outcomes of over 40,000 patients. A huge amount of data have been generated which allow comparison of practice patterns and outcomes analysis between Europe and North America. The aggregate data from the first 5 years of data collection not only make for interesting comparison but also allow examination of regional difference in practice patterns. For example, in the EACTS, out of 4,273 neonates, 885 (20.7%) underwent arterial switch procedures and 297 (6.95%) underwent Norwood stage 1 procedures. In the STS, out of 3,988 neonates, 472 (11.8%) underwent arterial switch procedures and 575 (14.4%) underwent Norwood stage 1 procedures. CONCLUSIONS: This analysis of the EACTS-STS multi-institutional outcomes database confirms that in both Europe and North America, case complexity and mortality is highest among neonates, then infants, and then children. Regional differences in practice patterns are demonstrated, with the overall goal being the continued upgrade in the quality of surgery for congenital heart disease worldwide.

Databases, Factual↗
PubMed2005

Late neurodevelopmental outcome after repair of total anomalous pulmonary venous connection.

Objective We sought to define the neurodevelopmental status of school-aged survivors of total anomalous pulmonary venous connection repaired during infancy. Methods All school-aged survivors of total anomalous pulmonary venous connection repair performed at a single institution were eligible. Thirty children returned for neurologic examination and neurodevelopmental testing. Results The median age at total anomalous pulmonary venous connection repair was 16 days (range, 1-141 days), and age at testing was 11 years (range, 6-19 years). Pulmonary venous return was supracardiac in 14 patients, infracardiac in 12 patients, cardiac in 3 patients, and mixed in 1 patient. Preoperative obstructed total anomalous pulmonary venous connection was present in 6 patients. Circulatory arrest was used in all repairs, with a median duration of 35 minutes (range, 17-55 minutes). At follow-up, microcephaly (head circumference <5%) was present in 28%. Neuromuscular examination was suspect or abnormal in 27%. Mean Full-scale IQ (95.3 +/- 18.5) and Verbal IQ (98.6 +/- 20.2) were not different from population norms, but Performance IQ (92.3 +/- 16.9) was significantly lower than population norms ( P = .02). Fine motor skills and visual-motor coordination were significantly impaired ( P < .01 for Grooved Pegboard and Test of Visual-Motor Integration). Patients with total anomalous pulmonary venous connection also had difficulty with tests of attention (Test of Everyday Attention for Children, P < .01), but results of tests of memory function were not significantly different from population norms. Conclusions School-aged survivors of infant total anomalous pulmonary venous connection repair exhibit a significant incidence of neurodevelopmental difficulties. Fine motor function, visual-motor integration, and attention are the most commonly affected domains. Evaluation of these children is indicated to identify those who are at risk for learning disabilities and who could benefit from early intervention.

Actuarial Analysis↗
PubMed2005

Chronic hypoxemia increases myocardial cytochrome oxidase.

OBJECTIVE: Cyanotic patients have potentially decreased tissue oxygen tension. Cytochrome oxidase catalyzes the reduction of oxygen and is integral to adenosine triphosphate production. Cytochrome oxidase subunit I, the active site, is encoded by mitochondrial DNA. Using a newborn swine model of chronic hypoxemia, we evaluated ventricular cytochrome oxidase subunit I mRNA and protein expression and assessed cytochrome oxidase activity. METHODS: Thirty-two newborn piglets underwent thoracotomy and placement of a pulmonary artery-to-left atrium shunt or sham operation. Two weeks later, partial pressure of arterial oxygen, hematocrit, and left ventricular shortening fraction values were compared with baseline values. Northern blot hybridization and protein immunoblotting for ventricular cytochrome oxidase subunit I were performed. Cytochrome oxidase kinetic activity was measured. Heme a,a3 content and turnover number were determined. Significance was assessed with a t test. RESULTS: Baseline partial pressure of arterial oxygen and hematocrit values were similar. Hypoxemic piglets had a lower partial pressure of arterial oxygen of 38 +/- 10 mm Hg (P < .001) and higher hematocrit value of 31.4% +/- 2.9% (P < .001) compared with a partial pressure of arterial oxygen of 140 +/- 47 mm Hg and hematocrit value of 24.6% +/- 3.9% after the sham operation. Baseline and postprocedure left ventricular shortening fraction were similar within and between groups. Chronic hypoxemia increased right ventricular and left ventricular cytochrome oxidase I mRNA and protein by more than 1.4-fold. Cytochrome oxidase activity increased significantly in hypoxemia by 2.5-fold compared with that seen after the sham operation. Heme a,a3 content and turnover number increased by 1.5-fold during hypoxemia. CONCLUSIONS: Chronic hypoxemia increases cytochrome oxidase I message, protein expression, and activity. The increase in kinetics was due to increased enzyme content and catalytic activity. This is a possible adaptive mechanism that might preserve organ function during chronic hypoxemia.

Animals↗
PubMed2005

Effect of congenital heart disease on neurodevelopmental outcomes within multiple-gestation births.

OBJECTIVES: We sought to assess the effect of congenital heart disease requiring surgical intervention with cardiopulmonary bypass at 6 months of age or less on developmental outcomes and growth at 1 year of age while controlling for socioeconomic status, prematurity, home environment, and parental intelligence. METHODS: We performed within-family comparison of 11 multiple-gestation births in which one child had congenital heart disease. At 1 year of age, the Bayley Scales of Infant Development II were administered, and growth parameters were assessed. Paired comparisons were made by using fixed effects regression conditioned on family. RESULTS: The multiple-gestation subjects were mildly premature on average (mean gestational age, 35.4 +/- 3.0 weeks). At 1 year of age, children with congenital heart disease scored lower on the Mental Development Index (85.0 +/- 19.3 vs 93.9 +/- 16.0, P = .037) and the Psychomotor Development Index (76.6 +/- 16.9 vs 91.3 +/- 14.9, P = .015) on the Bayley Scales of Infant Development II than did their siblings without congenital heart disease. There were no differences between siblings in weight, height, or head circumference. CONCLUSIONS: The presence of congenital heart disease requiring surgical intervention with cardiopulmonary bypass at 6 months of age or less is associated with a deficit in developmental achievement at 1 year of age, as measured by using the Bayley Scales of Infant Development II.

Female↗
PubMed2005

Haemodynamic changes during modified ultrafiltration immediately following the first stage of the Norwood reconstruction.

BACKGROUND: Modified ultrafiltration has been shown to reverse haemodilution and improve ventricular function following cardiopulmonary bypass. There has been concern, however, about the safety and efficacy of modified ultrafiltration after the first stage of Norwood reconstruction for palliation of neonates with hypoplasia of the left heart and its variants. METHODS: We reviewed the intraoperative course of all patients undergoing the first stage of Norwood reconstruction between September 1, 2000, and August 31, 2002. RESULTS: The first stage of reconstruction was performed in 99 neonates, 78 with classical hypoplasia of the left heart, and 21 with variants. Mean weight at surgery was 3.1 plus or minus 0.7 kilograms. Genetic syndromes, weight less than or equal to 2.5 kilograms, and/or major additional cardiac or non-cardiac anomalies, were present in 44 patients. We deemed these patients to constitute the group at high risk. A modified Blalock-Taussig shunt was utilized in 95 patients, and a conduit from the right ventricle to the pulmonary arteries in 4. Deep hypothermic circulatory arrest was used in all patients for a mean period of 45 minutes, plus or minus 15 minutes. Total support time on cardiopulmonary bypass plus deep hypothermic circulatory arrest was 100 minutes plus or minus 26 minutes. Modified ultrafiltration was performed in all patients. The mean duration of modified ultrafiltration was 10 plus or minus 2 minutes, and the total volume of filtrate removed was 104 plus or minus 29 millilitres per kilogram. There were no complications from modified ultrafiltration, and no patient required discontinuation of modified ultrafiltration for haemodynamic instability. During modified ultrafiltration, the haematocrit increased from 31 percent plus or minus 4 to 46 percent plus or minus 6. Heart rate decreased from 170 plus or minus 17 beats per minute to 158 plus or minus 16 beats per minute. Systolic blood pressure increased from 57 plus or minus 12 to 63 plus or minus 13 millimetres of mercury, and diastolic blood pressure from 30 plus or minus 8 to 35 plus or minus 7 millimetres of mercury. All these values are significant at a p value of less than 0.0001. Hospital morality in the patients at low risk was 3 of 55 (5.5 percent), but was 12 of 44 (27.3 percent) in the patients deemed to be at high-risk. CONCLUSIONS: Modified ultrafiltration is safe procedure following the first stage of Norwood reconstruction, with improvement in all haemodynamic parameters measured. Modified ultrafiltration is an additional incremental strategy, which may contribute to the overall improvement in outcome following surgical palliation of patients with hypoplasia of the left heart or its variants.

Cardiac Surgical Procedures↗
PubMed2005

Surgical management of unbalanced atrioventricular canal defect.

Approximately 10% of endocardial cushion defects exhibit unbalance at the atrioventricular inlet. When the atrioventricular valve sits more over one ventricle than the other, the contralateral ventricle is typically hypoplastic. Surgical intervention for unbalanced atrioventricular canal has a much higher morbidity and mortality than for the balanced form of the defect. With unbalanced atrioventricular canal to the right, no universal criteria are in place to choose single versus biventricular repair. In many cases, risk factors have been extrapolated from other lesions with left ventricular hypoplasia. Even if biventricular repair is successful, the reoperation rate is high for this lesion. Little data exist in the literature regarding left unbalanced atrioventricular canal. In general, right ventricular hypoplasia is better tolerated than left ventricular hypoplasia, and biventricular repair is usually possible. If cyanosis or high systemic venous pressure results, the one and one half ventricle repair (biventricular repair with bidirectional Glenn anastomosis) is an option. This article reviews the present understanding of unbalanced atrioventricular canal and discusses diagnostic and surgical strategies for this complex lesion.

Atrioventricular Node↗
PubMed2005

Electrographic neonatal seizures after infant heart surgery.

PURPOSE: Neonatal seizures are relatively common and an important early sign of acute encephalopathy in those who survive infant heart surgery. The contemporary occurrence of seizures in this setting is not fully known, and their electrographic characteristics are incompletely described. This study describes the characteristics of electrographic neonatal seizures (ENSs) in contemporary infants with congenital heart disease (CHD) surgically repaired by using cardiopulmonary bypass, with or without deep hypothermic circulatory arrest. METHODS: Consecutive infants undergoing heart surgery were monitored by video-EEG for 48 h postoperatively to establish the time of first seizure, total number of ENSs, site(s) of ENS(s) origin and other characteristics. RESULTS: ENSs occurred in 21 (11.5%) of 183 infants. None had clinically visible seizures. The mean time to the first ENS was 21 h (range, 10-36 h). The total number of ENSs among the entire cohort was 1,429. Mean total number of ENSs per patient over a 48-h period was 72 (range, 1-217). Phenobarbital administration was associated with a > or =50% reduction in seizure counts in five (41.7%) of 12 subjects. CONCLUSIONS: ENSs were relatively common in a large, contemporary cohort of infants after infant heart surgery. A wide variation was noted in seizure burden, but many experienced numerous seizures. Electrographic neonatal seizures are a candidate outcome end point in future neuroprotection trials in this patient population.

Cardiac Surgical Procedures↗
PubMed2004

Efficacy of prophylactic epicardial pacing leads in children and young adults.

BACKGROUND: Epicardial pacemakers are often required in children and young adults who cannot undergo a transvenous system because of patient size, vascular barriers, or significant residual intracardiac shunts. Prophylactic epicardial pacing leads, placed at the time of concomitant congenital heart surgery, may reduce a late thoracotomy or sternotomy. The efficacy of prophylactic epicardial leads in the pediatric population is unknown. METHODS: A retrospective review of the cardiovascular surgery and pacemaker databases at The Children's Hospital of Philadelphia identified all patients less than or equal to 21 years of age, who underwent placement of an epicardial pacing lead between January 1, 1990 and December 31, 2002. Prophylactic epicardial pacing leads placed at the time of a concomitant congenital heart procedure were compared to standard epicardial leads that were connected to a simultaneous programable generator. Pacing and sensing threshold data were obtained in prophylactic epicardial leads at the time of lead retrieval and 6 month follow-up and compared to standard epicardial pacing leads. RESULTS: Twenty-two (13 ventricular, 9 atrial) prophylactic epicardial pacing leads were retrieved in 13 patients at a median of 252 days (7 days to 3.98 years) from the time of initial implant and compared to 256 (164 ventricular, 92 atrial) standard epicardial leads placed in 142 patients. Nineteen (86%) prophylactic epicardial leads had acceptable pacing and sensing thresholds at lead retrieval. Only 1 patient with atrial and ventricular leads had poor pacing and sensing at retrieval and required a redo-sternotomy for placement of new atrial and ventricular epicardial pacing leads. For the remaining atrial (n = 7) and ventricular (n = 12) prophylactic epicardial leads, there was no significant difference in pacing (atrial, 1.59 +/- 1.1 microJ; ventricular, 1.98 +/- 1.9 microJ) or sensing (atrial, 3.6 +/- 1.8 mV; ventricular, 13.8 +/- 4.4 mV) compared to standard pacing (atrial, 2.1 +/- 1.8 microJ; ventricular, 1.9 +/- 3.4 microJ) and sensing (atrial, 3.3 +/- 1.7 mV; ventricular, 11.3 +/- 5.3 mV) epicardial leads. Six-month follow-up pacing and sensing thresholds were not significantly different between the prophylactic and standard epicardial pacing leads. CONCLUSIONS: Prophylactic epicardial pacing leads can be successfully placed and retrieved in a subset of children and young adults who will likely require pacing at a later date. Prophylactic leads have comparable pacing and sensing qualities at lead retrieval and short-term follow-up compared to standard epicardial leads. Consideration for prophylactic epicardial pacing leads will likely reduce the need for a late thoracotomy or sternotomy.

Adolescent↗
PubMed2004

Improving outcomes in functional single ventricle and total anomalous pulmonary venous connection.

BACKGROUND: We have previously reported that the outcome of infants with functional single ventricle and total anomalous pulmonary venous connection is poor relative to that of other single ventricle patients. Younger age at initial operation and obstructed total anomalous pulmonary venous connection were found to be risk factors for mortality. A review of our recent experience was undertaken to determine whether results in these patients are improving. METHODS: Medical records of 18 patients admitted after 1997 were reviewed (group B) and compared with the previous group of 73 patients admitted between 1984 and 1997 (group A). Data were analyzed using a Cox proportional hazards model. RESULTS: Median age at first operation was the same for both groups. The incidence of obstructed total anomalous pulmonary venous connection was not significantly different between groups (29% versus 33%, p = 0.70). Early survival is significantly improved for group B compared with group A (p = 0.015). Only group and younger age at initial operation were found to be risk factors for mortality. In the current group, 5 patients have undergone superior cavopulmonary connection with one death, 3 have undergone Fontan completion with no deaths, and heart or heart-lung transplantation was performed in 5 patients with two deaths. CONCLUSIONS: Early survival in patients with single ventricle and total anomalous pulmonary venous connection has improved significantly in recent years, but intermediate survival is still approximately 50%. Selective management using staged reconstructive surgery and transplantation may result in improved survival. Further study may identify risk factors for mortality and improve selection of appropriate patients for each therapy.

Abnormalities, Multiple↗
PubMed2004

Postpericardiotomy syndrome after permanent pacemaker implantation in children and young adults.

BACKGROUND: Postpericardiotomy syndrome (PPS) occurs in 10% to 50% of pediatric patients after cardiac surgery. The incidence and outcome of PPS after permanent pacemaker implantation in children is not described. METHODS: A retrospective analysis was performed of all pediatric patients who underwent isolated placement of a pacemaker between January 1984 and December 2002. Patients who underwent congenital heart surgery at the time of pacemaker implantation were excluded. PPS was diagnosed on the basis of clinical symptoms with echocardiographic confirmation of a pericardial effusion. RESULTS: Four hundred and forty-three pacemakers (237 epicardial, 206 transvenous) were implanted in 370 patients (median age 10 years, range 2 months to 24 years). Eight (2%) episodes of PPS (6 epicardial, 2 transvenous) occurred in 7 patients. The median time from implantation to PPS was 12.5 days (range 8 to 22 days). Six (75%) episodes followed primary pacemaker implantation, two occurred after subsequent lead revision. Three patients were initially treated with medical therapy (1 nonsteroidal agents, 2 steroids), and 1 required subsequent pericardiocentesis. Five patients underwent initial pericardiocentesis followed by medication. One patient had echocardiographic recurrence of a pericardial effusion 3 weeks after a nonsteroidal taper, with resolution after nonsteroidal agents were reinitiated. One patient required a pericardial window for a persistent effusion. No pacemaker was explanted. CONCLUSIONS: PPS occurred in 2% of children undergoing isolated pacemaker implantation of both epicardial and transvenous systems. PPS is usually managed successfully with medical therapy. Patients with medical treatment failure were successfully treated with pericardiocentesis or the surgical creation of a pericardial window.

Adolescent↗
PubMed2004

Lessons learned from the data analysis of the second harvest (1998-2001) of the Society of Thoracic Surgeons (STS) Congenital Heart Surgery Database.

OBJECTIVE: The analysis of the second harvest of the STS Congenital Heart Surgery Database produced meaningful outcome data and several critical lessons relevant to congenital heart surgery outcomes analysis worldwide. METHODS: This data harvest represents the first STS multi-institutional experience with software utilizing the nomenclature and database requirements adopted by the STS and EACTS (April 2000 Annals of Thoracic Surgery). Members of the STS Congenital Heart Committee analyzed the STS data. RESULTS: This STS harvest includes data from 16 centers (12787 cases, 2881 neonates, 4124 infants). In 2002, the EACTS reported similar outcome data utilizing the same database definitions (41 centers, 12736 cases, 2245 neonates, 4195 infants). Lessons from the analysis include: (1) Death must be clearly defined. (2) The Primary Procedure in a given operation must be documented. (3) Inclusionary and exclusionary criteria for all diagnoses and procedures must be agreed upon. (4) Missing data values remain an issue for the database. (5) Generic terms in the nomenclature lists, that is terms ending in Not Otherwise Specified (NOS), are redundant and decrease the clarity of data analysis. (6) Methodology needs to be developed and implemented to assure and verify data completeness and data accuracy. 'Operative Mortality' and 'Mortality Assigned to this Operation' were defined by the STS and EACTS; these definitions were not utilized uniformly. 'Thirty Day Mortality' was problematic because some centers did not track mortality after hospital discharge. Only 'Mortality Prior to Discharge' was consistently reported. Designation of Primary Procedure for a given operation determines its location for analysis. Until Complexity Scores lead to automated methodology for choosing the Primary Procedure, the surgeon must designate the Primary Procedure. Inclusionary and exclusionary criteria for all diagnoses and procedures have been developed in an effort to define acceptable concomitant diagnoses and procedures for each analysis. Improvements in data completeness can be achieved using a variety of techniques including developing more functional techniques of data entry at individual institutions and software improvements. Future versions of the STS Congenital Database will request that the coding of diagnoses and procedures avoid the terms ending in NOS. CONCLUSIONS: Lessons from this data harvest should improve congenital heart surgery outcome analysis.

Databases, Factual↗
PubMed2004

Risk factors for primary graft failure after pediatric cardiac transplantation: importance of recipient and donor characteristics.

BACKGROUND: Primary graft failure, or circulatory insufficiency immediately after transplantation, frequently occurs after pediatric cardiac transplantation and is the most common cause of death after infant transplantation. Risk factors for pediatric primary graft failure are poorly defined. METHODS: We retrospectively reviewed donor, procedural and recipient characteristics for primary graft failure in 165 pediatric cardiac transplant recipients (median age at transplant 1.1 years) by multivariatle logistic regression. Primary graft failure was defined as the need for mechanical circulatory support or use of multiple intravenous inotrope/pressors, including epinephrine, for circulatory support within the first 24 hours after transplantation. RESULTS: Primary graft failure occurred in 54 patients (33%); 24 patients (15%) required mechanical support for their graft failure; and primary graft failure was the cause of death or graft loss in 10 patients. Recipient risk factors associated with an increased risk of primary graft failure included diagnosis of congenital heart disease and a need for mechanical support before transplantation. Ventilator support before transplantation and maximal pulmonary vascular resistance index were risk factors for the development of isolated right ventricular graft failure. Donor risk factors associated with an increased risk for primary graft failure included increasing donor recipient weight and body surface area ratios; increasing donor ischemic time; anoxia as a cause of death; and increasing cardiopulmonary resuscitation time. Donor blood type O+ and hyperdynamic donor systolic function were associated with a decreased risk of primary graft failure. CONCLUSIONS: Multiple donor, recipient and procedural risk factors, including the type and severity of heart disease in the recipient before transplantation, are associated with primary graft failure after pediatric cardiac transplantation. Avoidance of matching high-risk donors to high-risk recipients may improve morbidity and mortality after transplantation.

Adolescent↗
PubMed2004

Periventricular leukomalacia is common after neonatal cardiac surgery.

OBJECTIVES: Periventricular leukomalacia is necrosis of the cerebral white matter adjacent to the lateral ventricles and results from injury to immature oligodendroglia. In infants without congenital heart disease, periventricular leukomalacia is associated with an increased incidence of developmental delay and attention deficit/hyperactivity disorder. The incidence of periventricular leukomalacia and the risk factors for development of periventricular leukomalacia after infant cardiac surgery are not known. METHODS: Magnetic resonance imaging of the brain was performed 6 to 14 days after cardiac surgery utilizing cardiopulmonary bypass with or without deep hypothermic circulatory arrest in 105 neonates and infants < or = 6 months of age. RESULTS: Median age at surgery was 6 days (range 1-178), with 82 neonates (age < or = 30 days). Periventricular leukomalacia was found in 44 of the neonates (54%) compared with 1 of 23 infants (4%). Forward logistic regression using age at surgery as a continuous variable identified a model containing longer total support time (cardiopulmonary bypass plus deep hypothermic circulatory arrest), lower systolic blood pressure at cardiac intensive care unit admission postoperatively, lower minimum diastolic blood pressure, and Po(2) in the first 48 hours after surgery. When age at surgery was considered as a dichotomous variable (neonate versus infant), younger age at surgery replaced systolic blood pressure, Po(2), and total support time in the model. Lower minimum diastolic blood pressure was a significant risk factor in both models. CONCLUSIONS: Periventricular leukomalacia was found in >50% of neonates after cardiac surgery but rarely in older infants. Hypoxemia and hypotension in the early postoperative period, particularly diastolic hypotension, may be important risk factors for periventricular leukomalacia.

Apolipoproteins E↗
PubMed2004

Preoperative cerebral blood flow is diminished in neonates with severe congenital heart defects.

OBJECTIVE: Impaired neurodevelopmental outcome represents a major morbidity for survivors of infant heart surgery for congenital heart defects. Previous studies in these neonates have reported preoperative microcephaly, periventricular leukomalacia, and other findings. The hypothesis of this study is that preoperative cerebral blood flow is substantially diminished and might relate to preoperative neurologic conditions. METHODS: Preoperative brain magnetic resonance imaging was performed. Cerebral blood flow measurements in infants with congenital heart defects were obtained by using a novel noninvasive magnetic resonance imaging technique, pulsed arterial spin-label perfusion magnetic resonance imaging. Cerebral blood flow was measured before the operation under standard ventilation and repeated after increased carbon dioxide. RESULTS: A total of 25 term infants were studied. The average age at the time of the operation was 4.4 +/- 4.6 days. Congenital heart defects varied widely. Microcephaly occurred in 24% (6/25). Baseline cerebral blood flow was 19.7 +/- 9.2 mL . 100 g -1 . min -1 (8.0-42.2 mL . 100 g -1 . min -1 ). Five patients had cerebral blood flow measurements of less than 10 mL . 100 g -1 . min -1 . Mean hypercarbic cerebral blood flow increased to 40.1 +/- 20.3 mL . 100 g -1 . min -1 (11.4-94.0 mL . 100 g -1 . min -1 , P < .001). Pairwise analyses found that low hemoglobin levels were associated with higher baseline cerebral blood flow values ( P = .04). Periventricular leukomalacia occurred in 28% (7/25) and was associated with decreased baseline cerebral blood flow values ( P = .05) and a smaller change in cerebral blood flow with hypercarbia ( P = .003). CONCLUSIONS: Structural brain abnormalities are common in these neonates before surgical intervention. Preoperative cerebral blood flow for this cohort was low and drastically reduced in some patients. Low cerebral blood flow values were associated with periventricular leukomalacia. Carbon dioxide reactivity was preserved but might be compromised by some aspects of the cardiac anatomy. The full spectrum of cerebral blood flow measurements with this technique in congenital heart defects and their long-term significance require continued investigation.

Brain↗