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Biomedical subjects

Stephen P Sanders

Publications and source records attributed to Stephen P Sanders.

At least 19 recordsLinked to original sources
PubMed2006

Cerebral blood flow during cardiopulmonary bypass in pediatric cardiac surgery: the role of transcranial Doppler--a systematic review of the literature.

BACKGROUND: Transcranial Doppler Ultrasound (TCD) is a sensitive, real time tool for monitoring cerebral blood flow velocity (CBFV). This technique is fast, accurate, reproducible and noninvasive. In the setting of congenital heart surgery, TCD finds application in the evaluation of cerebral blood flow variations during cardiopulmonary bypass (CPB). METHODOLOGY: We performed a search on human studies published on the MEDLINE using the keyword "trans cranial Doppler" crossed with "pediatric cardiac surgery" AND "cardio pulmonary by pass", OR deep hypothermic cardiac arrest", OR "neurological monitoring". DISCUSSION: Current scientific evidence suggests a good correlation between changes in cbral blood flow and mean cerebral artery (MCA) blood flow velocity. The introduction of Doppler technology has allowed an accurate monitorization of cerebral blood flow (CBF) during circulatory arrest and low-flow CPB. TCD has also been utilized in detecting cerebral emboli, improper cannulation or cross clamping of aortic arch vessels. Limitations of TCD routine utilization are represented by the need of a learning curve and some experience by the operators, as well as the need of implementing CBF informations with, for example, data on brain tissue oxygen delivery and consumption. CONCLUSION: In this light, TCD plays an essential role in multimodal neurological monitorization during CPB (Near Infrared Spectroscopy, TCD, processed electro encephalography) that, according to recent studies, can help to significantly improve neurological outcome after cardiac surgery in neonates and pediatric patients.

Aorta, Thoracic↗
PubMed2006

Biventricular repair of right-dominant complete atrioventricular canal defect.

Complete atrioventricular (AV) canal defects usually have right and left valve components of approximately equal size, although unbalanced forms do occur. Optimal management of unbalanced AV canal defects is controversial, with no proven guidelines for choosing between biventricular repair and univentricular palliation. We describe successful biventricular repair of a right-dominant unbalanced AV canal with severe left AV valve stenosis. This case illustrates that severely unbalanced AV canal defects can be repaired successfully by tailoring the AV valve to distribute it equally between the ventricles, The increase in left ventricular volume after surgery exceeded prediction based on conformational change alone.

Atrioventricular Node↗
PubMed2006

Clinical outcome of 193 extracardiac Fontan patients: the first 15 years.

OBJECTIVES: We sought to evaluate the mid-term outcome of hospital survivors with extracardiac Fontan circulation. BACKGROUND: Few data exist about the mid-term and long-term results of the extracardiac Fontan operation. METHODS: From November 1988 to November 2003, 221 patients underwent an extracardiac Fontan procedure as primary (9 patients) or secondary (212 patients) palliation, at a mean age of 72.2 months (range 13.1 to 131.3 months). A total of 165 of 193 early survivors underwent programmed noninvasive follow-up evaluations and at least one cardiac catheterization. RESULTS: The overall survival, including operative deaths, was 85% at 15 years. Freedom from late failure among hospital survivors is 92% at 15 years. A total of 127 of 165 survivors (77%) were in New York Heart Association functional class I. The incidence of late major problems was 24% (42 major problems in 36 of 165 patients): 19 patients had arrhythmias (11%), 5 patients had obstruction of the extracardiac conduit (3%) and 6 of the left pulmonary artery (3.5%), and 5 patients experienced ventricular failure (3%), leading to heart transplantation in 3 patients. Protein-losing enteropathy was found in two patients (1%). The incidence of late re-interventions was 12.7% (21 of 165 patients, including 15 epicardial pacemaker implantations). Four patients died (2.3%), two after heart transplantation. CONCLUSIONS: After 15 years of follow-up, the overall survival, the functional status, and the cardiopulmonary performance of survivors of the extracardiac Fontan procedure compare favorably with other series of patients who underwent the lateral tunnel approach. The incidence of late deaths, obstructions of the cavopulmonary pathway, re-interventions, and arrhythmias is lower than that reported late after other Fontan-type operations.

Cardiovascular Diseases↗
PubMed2006

Genetic syndromes and outcome after surgical correction of tetralogy of Fallot.

BACKGROUND: Genetic syndromes occur in 20% of patients with tetralogy of Fallot (TOF). The impact of genetic syndromes on surgical repair of TOF in infancy is still under investigation. METHODS: This retrospective study reviews the outcome of 306 consecutive patients (median age, 5.1 months) who underwent primary (266) or staged (40) repair of TOF between 1994 and 2004. Total follow-up was 1,188 patient-years (mean, 57 months). RESULTS: Genetic syndromes were documented in 85 patients (27.8%), including 22q11 deletion (27), trisomy 21 (13), vertebral, anal, cardiac, tracheoesophageal, renal, and limb abnormalities (VACTERL, 12), and others (33). Hypoplastic pulmonary arteries (PA) were more common in syndromic (19/85 = 22.3%) than nonsyndromic TOF (20/221 = 9.04%) (p < 0.001). Primary repair was performed in 82.4% syndromic and 88.7% nonsyndromic TOF (p = not significant [NS]). Ten-year actuarial survival was 94.1 +/- 2.3% in nonsyndromic and 84.3 +/-4.2% in syndromic TOF (p < 0.001). Ten-year survival was 96.3 +/- 3.6% for del22q11, 100% for trisomy 21, 63.6 +/- 14.5% for VACTERL, and 78.5 +/- 7.3% for patients with other syndromes (p = 0.022). Survival in syndromic TOF with normal PA anatomy was 89.6 +/- 4.2% for primary repair and 85.7 +/- 12.8% for staged repair (p = NS); freedom from reoperation after complete repair was 74.4 +/- 6.4% for primary correction and 56.3 +/- 11.9% for staged repair (p = 0.04). Cox proportional hazard identified the presence of genetic syndrome (p = 0.011) and central PA hypoplasia (p = 0.002) as independent predictors of mortality. CONCLUSIONS: Pulmonary arborization defects and genetic syndromes other than del22q11 or trisomy 21, are associated with worse outcome after correction of TOF. Primary TOF repair in syndromic patients with normal PA anatomy is a valid surgical strategy, with no additional risk for mortality and higher freedom from reintervention.

Child↗
PubMed2005

Abnormal vasomotor function of the epicardial coronary arteries in children five to eight years after arterial switch operation: an angiographic and intracoronary Doppler flow wire study.

OBJECTIVES: This study sought to test the vasoreactivity of the translocated coronary arteries after arterial switch operation (ASO) using quantitative angiographic analysis and intracoronary Doppler flow wire velocimetry. BACKGROUND: Late coronary artery events occur in 3% to 8% of patients after the ASO. Previous studies of coronary flow reserve have yielded disparate results. METHODS: Nineteen children previously underwent ASO (13 boys, age 5.4 +/- 3.2 years, weight 22.3 +/- 10.6 kg), and six control patients were enrolled in the study. Each patient underwent quantitative angiographic assessment of the epicardial coronary arteries before and after administration of nitroglycerin and coronary blood flow volume assessment before and after administration of adenosine and acetylcholine. The results were compared between groups. RESULTS: Epicardial coronary artery dilation in response to intracoronary nitroglycerin was significantly less in the ASO group than in the control group (left anterior descending [LAD], 5.0 +/- 0.05% vs. 18.0 +/- 4.5%, p = 0.0009; right coronary artery [RCA], 4.0 +/- 0.07% vs. 32.7 +/- 12.7%, p = 0.006). Moreover, the coronary blood flow volume reserve was reduced in ASO patients compared with control patients after intracoronary infusion of acetylcholine (2.3 +/- 0.9 vs. 4.9 +/- 1.7, p = 0.0003) or adenosine (2.7 +/- 1.5 vs. 5 +/- 0.5, p = 0.002). CONCLUSIONS: Epicardial coronary arteries fail to dilate normally in children after ASO, and the calculated coronary flow volume reserve is consequently reduced.

Child↗
PubMed2005

Effects of aerobic exercise training in children after the Fontan operation.

It was demonstrated that patients who have undergone the Fontan operation can safely undertake exercise training and that this results in an improvement in aerobic capacity. These findings suggest that aerobic training could be useful in the long-term management of these patients to optimize their cardiovascular fitness for more active lives.

Child↗
PubMed2005

Anomalous origin of one pulmonary artery from the ascending aorta.

UNLABELLED: We describe the surgical repair in three infants presenting with one pulmonary artery arising from the ascending aorta, the other artery arising normally from the right ventricle via the pulmonary trunk. Repair consisted of reimplantation of the anomalous pulmonary artery to the pulmonary trunk, in association with repair of associated intracardiac malformations. All patients survived the surgical procedures, and were discharged in stable clinical condition. Subsequently, two of the three patients developed stenosis at the surgical anastomosis relatively early after the initial procedure, and underwent reoperation. Although survival after operation is now expected for this malformation, reports of late results are lacking. Larger numbers of operations are needed before we can reach definitive conclusions. The origin of one branch pulmonary artery from the ascending aorta in the presence of a pulmonary valve and main pulmonary artery is a very rare congenital cardiac anomaly. PATIENTS AND METHODS: Between January 1995 and June 2003, 3 infant girls presented with the origin of one branch artery from the ascending aorta, while the other pulmonary artery originated from the pulmonary trunk which was in continuity with the right ventricular outflow tract. The pulmonary artery that arose from the right ventricle was left in 2 and right in 1 patient. RESULTS: At the age 13, 48 and 62 days respectively, the patients underwent surgical repair consisting with reimplantation of the anomalous pulmonary artery branch to the pulmonary trunk in association with repair of intracardiac malformations. There were no hospital deaths. Postoperative complications included: prolonged intubation in two patients (10 and 16 days), low output syndrome in 1 patient, cardiac tamponade in 1 patient and seizures in 1 patient. All patients were discharged in good clinical condition. There have been no late deaths. Subsequently, two of the three patients developed stenosis at the surgical anastomosis relatively early after the initial procedure, and after unsuccessful balloon dilation, underwent surgical reoperation. CONCLUSIONS: Although operative survival is now possible for this malformation, reports of late results are lacking. Two of the three patients developed stenosis at the surgical anastomosis relatively early after surgery. Larger numbers of operations are necessaries to reach definitive conclusions.

Abnormalities, Multiple↗
PubMed2004

cTnT1, a cardiac troponin T isoform, decreases myofilament tension and affects the left ventricular pressure waveform.

Four isoforms of cardiac troponin T (cTnT), a protein essential for calcium-dependent myocardial force development, are expressed in the human; they differ in charge and length. Their expression is regulated developmentally and is affected by disease states. Human cTnT (hcTnT) isoform effects have been examined in reconstituted myofilaments. In this study, we evaluated the modulatory effects of overexpressing one cTnT isoform on in vitro and in vivo myocardial function. A hcTnT isoform, hcTnT(1), expressed during development and in heart disease but not in the normal adult heart, was expressed in transgenic (TG) mice (1-30% of total cTnT). Maximal active tension measured in skinned myocardium decreased as a function of relative hcTnT(1) expression. The pCa at half-maximal force development, Hill coefficient, and rate of redevelopment of force did not change significantly with hcTnT(1) expression. In vivo maximum rates of rise and fall of left ventricular pressure decreased, and the half-time of isovolumic relaxation increased, with hcTnT(1) expression. Substituting total cTnT charge for hcTnT(1) expression resulted in similar conclusions. Morphometric analysis and electron microscopy revealed no differences between wild-type (non-TG) and TG myocardium. No differences in isoform expression of tropomyosin, myosin heavy chain, essential and regulatory myosin light chains (MLC), TnI, or in posttranslational modifications of mouse cTnT, cTnI, or regulatory MLC were observed. These results support the hypothesis that cTnT isoform amino-terminal differences affect myofilament function and suggest that hcTnT(1) expression levels present during human development and in human heart disease can affect in vivo ventricular function.

Actin Cytoskeleton↗
PubMed2004

Morphology of bicuspid aortic valve in children and adolescents.

OBJECTIVES: The aim of this study was to determine the relationship between aortic valve morphology and valve dysfunction. BACKGROUND: The morphology of the bicuspid or bicommissural aortic valve (BAV) may predict the severity of valve dysfunction. Therefore, we assessed the relationship between BAV, aortic coarctation, and the degree of valve pathology in children. METHODS: A retrospective review of 1,135 patients with BAV who were identified between 1986 and 1999 was performed. Patients younger than 18 years of age with BAV that was identifiable via echocardiography were included. The most recent or last study of each patient before intervention or endocarditis was reviewed. Mild stenosis was defined as a valve gradient > or =2 m/s, moderate or greater aortic stenosis as > or =3.5 m/s. Aortic regurgitation was quantified using standard criteria. RESULTS: Median age was 3 years (range, 1 day to 17.9 years), and 67% of the patients were male. Right-coronary and left-coronary leaflet fusion were the most common types of BAV (70%). Aortic stenosis that was moderate or greater was observed most often in patients with right-coronary and non-coronary leaflet fusion (odds ratio 2.4, 95% confidence interval 1.6 to 3.6; p < or = 0.001). Similarly, right-coronary and non-coronary leaflet fusion was more often associated with moderate aortic regurgitation or greater (odds ratio 2.4, 95% confidence interval 1.2 to 4.7; p = 0.01). The majority of patients with aortic coarctation had fusion of the right-coronary and left-coronary leaflets (89%), and aortic coarctation was associated with lesser degrees of valve stenosis or regurgitation. CONCLUSIONS: Analysis of BAV morphology is of clinical and prognostic relevance. Fusion of the right-coronary and non-coronary leaflets was associated with more significant valve pathology, whereas fusion of the right-coronary and left-coronary leaflets was associated overwhelmingly with aortic coarctation and less aortic valve pathology.

Adolescent↗
PubMed2004

Pharmacokinetics and safety of TP10, soluble complement receptor 1, in infants undergoing cardiopulmonary bypass.

BACKGROUND: Increase in vascular permeability and multiorgan dysfunction after cardiopulmonary bypass (CPB) are barriers to successful cardiac surgery in infants. Complement inhibition with TP10, a C3/C5 convertase inhibitor (AVANT Immunotherapeutics, Needham, Mass), blunts post-CPB organ dysfunction in the neonatal pig. Methods and results The pharmacokinetics and safety of TP10 in infants (age <1 year, n = 15) undergoing CPB were examined in a phase I/II open-label prospective trial. TP10 (10 mg/kg) was given intravenously before CPB and also added (10 mg/100 mL prime volume) to the CPB circuit. TP10 plasma levels correlated with C3a levels and measures of clinical course. All infants survived. No adverse events were attributed to TP10. TP10 plasma concentration fell to < or =60 microg/mL 12 hours after CPB. A 2-compartment model was fit to the TP10 blood levels as a function of time. Based on this model, an initial dose of 10 mg/kg over 0.5 hours followed by 10 mg/kg over 23.5 hours is the most appropriate for maintaining TP10 concentration between 100 microg/mL and 160 microg/mL for 24 hours after CPB. C3a was lower 12 hours after CPB than before CPB and still lower 24 hours after CPB. TP10 concentration was inversely correlated with the 12-hour post-CPB to pre-CPB ratio of C3a (Spearman rho -0.76, P = -.016), and with total (rho -0.56, P =.047) and net (rho -0.85, P =.0016) fluid and blood product administration/kg >24 hours after CPB. CONCLUSIONS: TP10 administration to infants appears safe. Pharmacokinetic analysis generated an optimal dosing strategy to achieve effective TP10 levels for 24 hours after CPB. In the infant, TP10 appears to decrease CPB-induced complement activation and protect vascular function. These results support a phase III trial of TP10 in infants requiring CPB.

Capillary Permeability↗
PubMed2004

A randomized, placebo-controlled trial of amlodipine in children with hypertension.

OBJECTIVES: Evaluation of the efficacy and safety of amlodipine in hypertensive children. STUDY DESIGN: A randomized, double blinded, placebo-controlled, parallel-group, dose-ranging study was conducted at 49 centers in North and South America. The primary end point was the effect of amlodipine on systolic blood pressure (BP); secondary end points included the effect of amlodipine on diastolic BP, the effect of amlodipine as a function of dose and body size, and evaluation of safety. RESULTS: We enrolled 268 hypertensive children (mean age, 12.1 +/- 3.3 years); 84 (31.3%) had primary hypertension, and 177 (66%) were boys. Amlodipine produced significantly greater reductions in systolic BP than placebo; these were -6.9 mm Hg for 2.5 mg daily (P=.045 vs placebo) and -8.7 mm Hg for 5 mg daily (P=.005 vs placebo). The underlying cause of hypertension had no effect on the response to amlodipine. There was a significant dose-response effect of amlodipine on both systolic and diastolic BP beginning at doses > or =0.06 mg/kg per day. Systolic BP < or =95(th) percentile was achieved in 34.6% of subjects with systolic hypertension. Amlodipine was well tolerated, with just 6 children withdrawn from treatment because of drug-related adverse events. CONCLUSIONS: Amlodipine effectively lowers systolic BP in a dose-dependent manner in hypertensive children who require drug treatment.

Adolescent↗
PubMed2003

Outcome of unroofing procedure for repair of anomalous aortic origin of left or right coronary artery.

BACKGROUND: Anomalous aortic origin of a coronary artery (AAOCA) from an incorrect sinus of Valsalva is a relatively rare congenital defect and is associated with sudden death. Several surgical techniques have been described to address this defect, but functional outcome has never been addressed. In this report we evaluate a consecutive series of patients treated with unroofing techniques using transthoracic echocardiography, graded exercise testing, and stress echocardiography to assess functional repair. METHODS: Nine consecutive patients (range 7 to 65 years) underwent surgical repair of AAOCA from 1995 to 2001. In all patients the intramural segment was at or below the level of the commissure. All patients underwent a modified unroofing procedure to move the coronary artery orifice to the appropriate sinus. In 2 patients, a new orifice was created without significant unroofing and disruption of the commissure. Patients were evaluated prospectively with exercise electrocardiography testing and by resting and stress echocardiography. RESULTS: Of the 9 patients, 8 presented with symptoms suggestive of ischemia (chest pain, dyspnea on exertion, or syncope). Six patients had anomalous left main coronary artery arising from the right sinus of Valsalva, and 3 patients had anomalous right coronary artery from the left sinus of Valsalva. Transthoracic echocardiography and graded exercise testing was performed in all 9 patients (mean 29 months, range 4 to 85 months) after repair. Of the 9 patients, 8 also underwent stress echocardiography. In 8 of 9 patients the newly created coronary artery ostium was visualized by either two-dimensional echocardiography or color flow Doppler. All patients were symptom free at the time of follow-up. Exercise stress echocardiography was negative in all patients. Of the 8 patients, 7 had normal left ventricular shortening. No patients had regional wall motion abnormalities suggestive of ischemia. All patients were intervention free except 1 patient who developed severe aortic insufficiency and underwent a subsequent Ross procedure 44 months after his initial procedure. CONCLUSIONS: Anomalous origin of a coronary artery from an incorrect sinus of Valsalva is known to be associated with increased risk of sudden death. Surgical correction can be carried out with minimal risk and good anatomic and functional results. Manipulation of the commissure can be avoided by creation of a neo-ostia without extensive unroofing of the intramural segment or manipulation of the intercoronary commissure. This may avoid aortic valve malfunction.

Adolescent↗
PubMed2002

Coronary artery pattern and outcome of arterial switch operation for transposition of the great arteries: a meta-analysis.

BACKGROUND: Prior studies of coronary pattern and outcome after arterial switch operation (ASO) for transposition of the great arteries (TGA) have been hindered by limited statistical power. This meta-analysis assesses the effect of coronary anatomy on post-ASO mortality, both overall and adjusted for time. METHODS AND RESULTS: A literature search revealed 9 independent series that reported post-ASO mortality by coronary pattern in a total of 1942 patients. Odds ratios comparing all-cause mortality in patients with usual versus variant coronary patterns were calculated and combined by use of an empirical Bayesian model. Single coronary patterns, both of which loop around the great vessels, were associated with significant mortality (OR 2.9, 95% CI 1.3 to 6.8), whereas looping patterns that arose from 2 separate ostia were not (OR 1.2, 95% CI 0.8 to 1.9). This latter group includes patients with the most common variant, circumflex from right coronary artery. Patients with an intramural coronary artery had the greatest mortality (OR 6.5, 95% CI 2.9 to 14.2). Overall, patients with any variant coronary pattern had nearly twice the mortality seen in those with the usual pattern (OR 1.7, 95% CI 1.3 to 2.4). Single ostium patterns and intramural coronary arteries remained associated with significant added mortality after adjustment for time-trend effects. CONCLUSIONS: Over the past 2 decades, patients with common coronary variants have undergone ASO without added mortality compared with those with the usual coronary pattern. Those with intramural or single coronary arteries have significant added mortality that has persisted over time.

Coronary Vessel Anomalies↗