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Biomedical subjects

Ivan M Rebeyka

Publications and source records attributed to Ivan M Rebeyka.

12 recordsLinked to original sources
PubMed2006

Antenatal diagnosis and successful surgical removal of a large right ventricular fibroma.

Congenital cardiac tumors are very rare and fibromas are the second most common type. Fibromas are benign tumors, but they have potentially serious complications. Their antenatal diagnosis is infrequently reported in the literature, and the management of these tumors is a source of controversy. We report the case of a rare form of right ventricular free wall fibroma. Antenatal diagnosis was made at 36 weeks of gestation, with subsequent successful resection at 2 weeks of age. A brief review of the literature focuses on the diagnostic approach and the clinical and surgical management of congenital cardiac fibromas.

Cardiac Surgical Procedures↗
PubMed2006

The rapid prototyping of anatomic models in pulmonary atresia.

OBJECTIVE: The goal of this study was to assess the utility and accuracy of solid anatomic models constructed with rapid prototyping technology for surgical planning in patients with pulmonary atresia with ventricular septal defect and major aortopulmonary collateral arteries. METHODS: In 6 patients with pulmonary atresia with ventricular septal defect and major aortopulmonary collateral arteries, anatomic models of the pulmonary vasculature were rapid prototyped from computed tomographic angiographic data. The surgeons used the models for preoperative and intraoperative planning. The models' accuracy and utility were assessed with a postoperative questionnaire completed by the surgeons. An independent cardiac radiologist also assessed each model for accuracy of major aortopulmonary collateral artery origin, course, and caliber relative to conventional angiography. RESULTS: Of the major aortopulmonary collateral arteries identified during surgery and conventional angiography, 96% and 93%, respectively, were accurately represented by the models. The surgeons found the models to be very useful in visualizing the vascular anatomy. CONCLUSION: This study presents the novel vascular application of rapid prototyping to pediatric congenital heart disease. Anatomic models are an intuitive means of communicating complex imaging data, such as the pulmonary vascular tree, which can be referenced intraoperatively.

Biomedical Engineering↗
PubMed2006

Intermediate-term outcomes of the arterial switch operation for transposition of great arteries in neonates: alive but well?

OBJECTIVES: This interprovincial inception cohort study outlines the operative and intermediate outcomes of all neonates at a single institution with a broad referral area who underwent the arterial switch operation for transposition of great arteries, including complex types. Predictors of outcome are explored. METHODS: A total of 88 consecutive neonates underwent the arterial switch operation between 1996 and 2004 with full-flow (150 mg/kg/min) cardiopulmonary bypass with selective deep hypothermic circulatory arrest. Overall and event-free survivals were calculated. Health and neurodevelopment (Bayley Scales of Infant Development II) were assessed at 18 to 24 months of age. Univariate and multivariate analyses, sensitivity, and specificity were determined to identify preoperative, intraoperative, and postoperative factors associated with mental and/or motor delay. RESULTS: There was 1 operative mortality (1.1%). At the average 4-year follow-up, survival was 98.9% and freedom from reintervention was 93.2%. Eighty-five children were assessed. Three were excluded because of unrelated postoperative diagnoses. For the remaining 82, mean scores were 89 +/- 17 (49-118) for mental skills and 92 +/- 15 (49-125) for motor skills. Anatomic complexity, cardiopulmonary bypass, and deep hypothermic circulatory arrest times were not associated with developmental outcome. Preoperative variables of low gestational age and high preoperative lactate correctly classified 84.1% of mentally and/or motor-delayed children. CONCLUSION: Transposition of great arteries, including complex types, can be corrected with low surgical risk and good intermediate survival; however, neurodevelopmental outcome is a concern. These data suggest that although anatomic complexity may not affect late outcome, there may be potentially modifiable preoperative factors that can be optimized to improve developmental outcomes.

Cardiac Surgical Procedures↗
PubMed2005

Pediatric poststernotomy mediastinitis.

BACKGROUND: Mediastinitis results in significant morbidity in pediatric cardiac patients. It is not clear whether delayed sternal closure is a risk factor for these infections. Management of mediastinitis remains controversial. METHODS: Cases of mediastinitis at the Stollery Children's Hospital from January 1, 1991, to June 30, 2004, were reviewed. RESULTS: There were 29 cases of mediastinitis in 2,675 open cardiac procedures for an overall incidence of 1.1%. Infection was diagnosed 5 to 27 days after the original surgical procedure (median, 10 days). The odds ratio for infection with delayed sternal closure versus primary sternal closure was 1.88 (95% confidence interval, 0.63 to 5.60). Signs at the onset of infection included fever (86%), incisional erythema (69%), purulent drainage from the incision or pacer wire sites (83%), and wound dehiscence (23%). Debridement was followed by primary sternal closure in all but three cases in which the sternum had not been closed before debridement and rotational muscle flaps were not used. Continuous irrigation systems were used only in the first 7 patients. One patient died of mediastinitis complicated by infective endocarditis, and 2 patients died of multiorgan failure. CONCLUSIONS: Delayed sternal closure was not a major risk factor for mediastinitis, especially if primary skin closure was used with delayed sternal closure. Excellent results were attained with debridement and primary closure of these infections.

Adolescent↗
PubMed2005

Use of an allograft patch in repair of hypoplastic left heart syndrome may complicate future transplantation.

OBJECTIVE: Cryopreserved allograft tissue used in the Norwood procedure for infants with hypoplastic left heart syndrome (HLHS) has the potential to cause marked immunologic sensitization which may complicate potential future heart transplantation, if required. The purpose of this study was to assess the anti-HLA antibody response to allograft patches used in the initial repair of HLHS. METHODS: A prospective cohort study was conducted comparing the panel-reactive antibody levels (PRA) in 12 infants undergoing repair of HLHS with cryopreserved allograft patch to 10 infants undergoing arterial switch for transposition of the great arteries (no allograft tissue used). PRA for Class I (HLA-A, B, C) and Class II (HLA-DR, DQ) antibodies were assessed preoperatively and postoperatively using flow cytometry. RESULTS: The two groups were well matched at the time of surgery (age, weight, gender). Infants in both groups received blood from multiple donors; however, the allograft group received significantly more (12+/-10 vs. 5+/-1 units; P<0.001). By 4 months, most infants receiving allograft tissue had become highly sensitized for both Class I PRA (62+/-40 vs. 0; P=0.002) and Class II PRA (49+/-42 vs. 2+/-3; P=0.022). This response continued to increase at 12 months: Class I PRA (79+/-21 vs. 0; P=0.008) and Class II PRA (66+/-27 vs. 5+/-6; P=0.008). Specificity analysis confirmed antibodies were specific for the donor allograft HLA type. In addition, infants who were coincidently HLA-matched with their allograft did not develop an elevated PRA. CONCLUSIONS: Allograft tissue used in the repair of HLHS is associated with profound donor specific immunologic sensitization in the majority of recipients and may complicate or jeopardize future transplantation. Methods to reduce the immunogenicity of cryopreserved allograft tissue used for arch reconstruction requires further investigation.

Adolescent↗
PubMed2005

Postoperative lactate concentrations predict the outcome of infants aged 6 weeks or less after intracardiac surgery: a cohort follow-up to 18 months.

OBJECTIVES: An observational cohort study was conducted in infants less than 6 weeks of age undergoing intracardiac surgery to examine the predictive value of serial postoperative lactate determination on survival and early childhood neurodevelopment. METHODS: A total of 85 infants with congenital heart disease underwent intracardiac surgery between 1996 and 1999. Differences in serial lactate concentrations after surgery among 3 outcome groups were compared. The predictive value of plasma lactate concentration on outcome (1) at discharge from initial hospitalization and (2) 18 to 24 months postnatal age was examined. RESULTS: Compared with survivors, the nonsurvivors had higher lactate concentrations on admission to the pediatric intensive care unit at day 1 peak and area under the curve of the lactate profile than those of adverse and intact survivors (all P < .001, analysis of variance). Significant differences in the time for lactate concentrations to return to 2 mmol/L or less during the first postoperative day were observed among the groups: nonsurvivors > adverse survivors > intact survivors. Lactate concentrations of less than 7 mmol/L on admission or less than 8 mmol/L at day 1 peak predicted survival with 82% sensitivity and 83% specificity, and positive and negative predictive values of 97% and 43%, respectively (P < .001, chi2). Plasma lactate concentrations were associated with adverse outcome but had lower predictive values compared with that for nonsurvival. CONCLUSIONS: Serial lactate determination accurately predicts survival and may help differentiate survivors with adverse outcome from those with intact neurodevelopment in early childhood.

Biomarkers↗
PubMed2005

Declining need for permanent pacemaker insertion with the bicaval technique of orthotopic heart transplantation.

BACKGROUND: The bicaval technique of orthotopic heart transplantation, in contrast to the standard biatrial technique, may better preserve right atrial anatomy and, thus, may be associated with less sinus node dysfunction and less atrioventricular valve dysfunction. OBJECTIVES: To compare the requirement for permanent pacemaker insertion and the incidence of atrioventricular valve dysfunction following heart transplantation with either the standard or the bicaval technique. PATIENTS AND METHODS: A retrospective analysis was conducted of a consecutive cohort of 105 patients, older than 18 years of age, undergoing heart transplantation with either the standard (n=48) or the bicaval (n=57) technique from December 1998 to December 2001. RESULTS: Cross-clamp (100 min versus 112 min; P=0.012) and donor ischemic (222 min versus 276 min; P=0.005) times were significantly prolonged in the bicaval group. Perioperative morbidity and mortality were statistically similar between the groups. Bicaval transplantation resulted in a significant decrease in the requirement for permanent pacemaker insertion at 30 days (13% versus 0%; P=0.008) and 90 days (17% versus 1.8%; P=0.01) after transplantation. There was a nonsignificant trend toward a decreased degree of tricuspid valve regurgitation (mean 1.81 versus 1.36; P=0.141) and mitral valve regurgitation (mean 1.04 versus 0.79; P=0.348) with the bicaval technique. CONCLUSIONS: Although associated with longer cross-clamp and donor ischemic times, the data demonstrated a significant reduction in the need for permanent pacemaker insertion at 30 and 90 days post-transplantation with the bicaval technique. There was no statistically significant difference in the degree of mitral and tricuspid valve regurgitation between the two groups.

Age Factors↗
PubMed2004

Outcomes from an interprovincial program of newborn open heart surgery.

OBJECTIVES: To determine 18-month neurodevelopmental outcome of survivors of complex open heart surgery at </=6 weeks of age through an interprovincial program and to explore preoperative, operative, and postoperative outcome predictors. Study design Of 85 children from this inception cohort (21% mortality), 67 18-month-old survivors received multidisciplinary assessment including the Bayley Scales of Infant Development-II. Cumulative risk for adverse outcome was determined through univariate and multivariate analyses. RESULTS: Survival of the 85 children included 23 of 23 after arterial switch, 16 of 26 after Norwood, six of six after total anomalous pulmonary venous drainage repair, and 22 of 30 after miscellaneous repair. Outcomes were as follows: in-hospital death, 14 (16%); postdischarge death, four (5%); motor/sensory disability, three (4%); motor/mental delay (<70), 21 (25%); and intact survivors, 43 (50%). Cohort mental (84+/-17) and motor (80+/-22) scores were lower for those with chromosomal abnormalities, 67+/-16 and 61+/-17, respectively. Fifty-five percent of the outcome variance was explained by duration of preoperative ventilation, 18%; genetic anomaly, 5%; intraoperative variables, 18%; and postoperative variables, 14%. CONCLUSIONS: Risk for adverse outcome is cumulative, with preoperative determinants contributing significantly to total variance. Potentially modifiable variables should be sought in an attempt to improve outcome.

Cardiac Surgical Procedures↗
PubMed2003

Dynamics of cryoprotectant permeation in porcine heart valve leaflets.

Valve replacement is a common cardiovascular procedure for the treatment of a variety of congenital and acquired defects. Many surgical programs rely on cryopreserved heart valves from regional tissue bank programs to meet clinical demands. Current cryopreservation strategies for heart valves are empirically derived. The aim of this study was to use proton nuclear magnetic resonance spectroscopy (NMR) to monitor changes in cryoprotectant concentration in isolated heart valve leaflets. Porcine aortic valves were locally obtained, freshly isolated, and allowed to equilibrate at various experimental temperatures (22 degrees C, 10 degrees C, 4 degrees C) for 1 h prior to immersion in 1 M Me2SO solution. At defined intervals (0, 0.25, 0.5, 1, 2, 6, and 24 h) the valves were removed from the Me2SO and the leaflets were rapidly dissected and equilibrated in deuterium oxide (D2O). Using previously described techniques the Me2SO concentration in the heart valve leaflets was determined by NMR and the diffusion coefficient was calculated as a function of time and temperature. Heart valve leaflets were fully equilibrated with Me2SO after approximately 2 h of exposure at 22 degrees C while equilibrium was not reached >6 h or more at 10 degrees C and 4 degrees C. These results indicate that that permeation of Me2SO in heart valves is strongly temperature dependent Furthermore, this study provides a quantitative measure of Me2SO permeation and cryoprotectant at equilibration in heart valve leaflets. The clinical applications of these findings may help to optimize the balance between the protective and toxic effects of cryoprotectants and lead to improved methods of preservation of heart valves.

Animals↗
PubMedDate not supplied

Pretransplant diabetes, not donor age, predicts long-term outcomes in cardiac transplantation.

BACKGROUND AND AIM: Accepting donors of advanced age may increase the number of hearts available for transplantation. Objectives were to review the outcomes of using cardiac donors 50 years of age and older and to identify predictors of outcome at a single institution. METHODS: A retrospective analysis of all adult cardiac transplants (n = 338) performed at our institution between 1988 and 2002 was conducted. RESULTS: Of these, 284 patients received hearts from donors <50 years old and 54 received hearts from donors > or =50 years old. Recipients of hearts from older donors had a greater frequency of pretransplant diabetes (19% vs 33%), renal failure (16% vs 30%), and dialysis (3% vs 9%). There were no differences in ICU or postoperative length of stay, days ventilated, or early rejection episodes. Recipients of older donor hearts, however, had increased perioperative mortality (7% vs 17%; p = 0.03). Multivariate analysis identified older donors (OR 2.599; p = 0.03) and donor ischemia time (OR 1.006; p = 0.002) as significant predictors of perioperative mortality. Actuarial survival at 1 (87% vs 74%), 5 (76% vs 69%), and 10 (59% vs 58%) years was similar (p = 0.08) for the two groups. Separate multivariate analyses identified pretransplant diabetes as the sole predictor of long-term survival (HR 1.659; p = 0.02) and transplant coronary disease (HR 2.486; p = 0.003). CONCLUSIONS: Despite increased perioperative mortality, donors > or =50 years old may be used with long-term outcomes similar to those of younger donor hearts. This has potential to expand the donor pool. Pretransplant diabetes has a significant impact on long-term outcomes in cardiac transplantation and requires further investigation.

Adolescent↗