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Biomedical subjects

Ali Dodge-Khatami

Publications and source records attributed to Ali Dodge-Khatami.

26 records · Page 2Linked to original sources
PubMed2003

Tracheal replacement in rabbits with a new composite silicone-metallic prosthesis.

A new composite silicone-metallic prosthesis was tested, studying the potential for respiratory epithelial covering over the biocompatible inner lining, in a rabbit survival model. Seven New Zealand White rabbits underwent near-total excision of their trachea and implantation of a sterile prosthesis. After 2 months, they were sacrificed and the prostheses were retrieved. Specimens were fixed and histologically examined for tissue reaction around the prosthesis, at the anastomotic lines, and particularly for the presence or absence of epithelialization of the inner lumen over the biocompatible surface. All rabbits survived the operation. At 2 months, the outer layer of the prosthesis was consistently covered with fibrosis and neutrophils. The inner layer showed necrotic cells and scant re-epithelialization over the biocompatible lining, up to 5 mm beyond the anastomosis, with no evidence of organized respiratory epithelium in the middle sections. The new prosthesis is a viable temporary solution for airway replacement in rabbits. Granulation tissue was not observed at the anastomosis, and re-epithelialization did occur, but failed to achieve full-length luminal covering. The potential for granulation tissue does not yet make this an ideal long-term solution. Improvements in prosthesis design or biocompatibility are required, and need to be re-evaluated before applicability for chronic use.

Animals↗
PubMed2003

Right ventricular function in congenital cardiac disease: noninvasive quantitative parameters for clinical follow-up.

Right ventricular function is of great importance in patients with both acute and chronic ventricular overload. The early detection of right ventricular dysfunction may have an impact on therapeutic decision making, helping to prevent or further delay functional deterioration of the right ventricle. In patients with right ventricular overload due to congenital cardiac diseases, dobutamine stress testing combined with magnetic resonance imaging, electrocardiographic changes, and monitoring of concentrations of plasma brain natriuretic peptide are very suitable parameters for the early detection of ventricular dysfunction, and should therefore be used in the follow-up of these patients. It is apparent that no single measurement of anatomy or function can ever adequately describe the form or performance of the right ventricle. Rather, we should be looking more towards an integrated approach of different parameters for right ventricular function. The quantitative parameters described in this study can serve this purpose. The strong correlation found between these non-invasive and independent parameters encourages their clinical implementation.

Child↗
PubMed2002

Usefulness of magnetic resonance imaging dobutamine stress in asymptomatic and minimally symptomatic patients with decreased cardiac reserve from congenital heart disease (complete and corrected transposition of the great arteries and subpulmonic obstruction).

We explored the effect of dobutamine stress and its possible clinical implications in different groups of asymptomatic patients with chronic right ventricular (RV) pressure overload due to congenital heart disease. Forty-seven asymptomatic and minimally symptomatic patients with chronic RV pressure overload were studied: 24 patients with systemic right ventricles (16 surgically corrected transposition of the great arteries (TGA) (Mustard or Senning), 8 congenitally corrected TGA), 23 patients with chronic pressure overloaded subpulmonic right ventricles, and 11 age- and sex-matched healthy volunteers. Magnetic resonance imaging (MRI) was performed both at baseline and during dobutamine stress to determine RV volumes and ejection fraction. At baseline, RV ejection fraction in patients with surgically corrected TGA was significantly lower than in controls (58 +/- 10% vs 70 +/- 8%, p = 0.02). During dobutamine stress, RV ejection fraction increased significantly in controls and patient groups except for patients with pressure overloaded subpulmonic right ventricles. RV stroke volume increased in controls (21 +/- 21%, p = 0.008); RV stroke volume remained unchanged in patients with congenitally corrected TGA and surgically corrected TGA (2 +/- 17%, p = NS; -8 +/- 29%, p = NS). A significant RV stroke volume decrease was observed in patients with subpulmonic right ventricles (-15 +/- 16%, p = 0.0002). The changes in RV stroke volume were accompanied by a significant decrease in RV end-diastolic volume (-13 +/- 14%, p = 0.001) in patients with subpulmonic right ventricles and in patients with surgically corrected TGA (-23 +/- 16%, p = 0.0001). In controls and in patients with congenitally corrected TGA there was no change in RV end-diastolic volume (3 +/- 15%, p = NS; -5 +/- 11%, p = NS). There is a clear heterogeneity in response to MRI dobutamine stress between different groups of patients with chronic RV pressure overload. Our data suggest impaired filling in surgically corrected TGA and decreased contractility in patients with chronic pressure overloaded subpulmonic right ventricles. Dobutamine stress MRI may facilitate follow-up of RV (dys)function in patients with chronic RV pressure overload due to congenital heart disease.

Adult↗
PubMed2002

Comparable systemic ventricular function in healthy adults and patients with unoperated congenitally corrected transposition using MRI dobutamine stress testing.

BACKGROUND: Failure of the systemic right ventricle (RV) often complicates adult survival in unoperated or physiologically repaired congenitally corrected transposition of the great arteries (CCTGA). Healthy controls schematically represent an optimal outcome of anatomic repair, which is increasingly performed to treat CCTGA. Magnetic resonance imaging dobutamine stress testing measures cardiac reserve, and sets to compare the left ventricle of controls with the systemic RV of unoperated and physiologically repaired patients with CCTGA. METHODS: Baseline and stress magnetic resonance imaging (maximum dobutamine dose, 15 microg/kg/min) assessed systemic RV function in 13 minimally or asymptomatic adult patients with CCTGA (unoperated, n = 7; physiologically repaired, n = 6). The left ventricles of 11 healthy age-matched adults served as controls. RESULTS: Baseline and stress end-diastolic volumes similar between the systemic RV of unoperated patients and the left ventricle of controls, as well as base end-systolic volumes. Stress ejection fraction was lower in unoperated and physiologically repaired patients (70 +/- 6% and 60 +/- 5%, respectively, vs healthy controls (84 +/- 8%). However, comparable with healthy controls, both subsets of CCTGA patients responded appropriately to dobutamine stress, as illustrated by similar RV stroke volume, heart rate, mean blood pressure, and cardiac index. CONCLUSIONS: Compared with the left ventricles of healthy controls, both patient groups had larger systemic RV volumes, diminished ejection fraction, but an appropriate response to dobutamine stress. Values of unoperated patients are closer to normal than physiologically repaired patients. Magnetic resonance imaging dobutamine may help to define the subgroups of CCTGA patients with favorable anatomy, whereby asymptomatic adult survival could be anticipated without the need for an operation.

Adolescent↗
PubMed2002

Anomalous origin of the left coronary artery from the pulmonary artery: collective review of surgical therapy.

Anomalous origin of the left coronary artery from the pulmonary artery is an extremely rare but potentially fatal congenital coronary anomaly. Prompt surgical reestablishment of a two-coronary system on diagnosis yields excellent results and allows progressive and nearly total myocardial recovery. Follow-up of all patients is required to assess the adequacy of repair and to exclude ongoing or recurrent myocardial insult.

Coronary Vessel Anomalies↗
PubMed2002

Surgical substrates of postoperative junctional ectopic tachycardia in congenital heart defects.

BACKGROUND: Junctional ectopic tachycardia is a major cause of postoperative morbidity after surgery for congenital cardiac disease. To elucidate the mechanism of junctional ectopic tachycardia, surgical correlations were studied in four types of congenital heart defects involving closure of a ventricular septal defect, relief of right ventricular outflow tract obstruction, or both. METHODS: Between 1997 and 1999, a total of 343 consecutive patients underwent repair of tetralogy of Fallot (n = 114), common truncus arteriosus (n = 10), ventricular septal defect (n = 161), and atrioventricular septal defect (n = 58). Variables studied included demographic and bypass data, surgical approaches toward ventricular septal defect closure and relief of right ventricular outflow tract obstruction, and resection as opposed to division of muscle bundles. RESULTS: Junctional ectopic tachycardia occurred most frequently after repair of tetralogy of Fallot (n = 25; 21.9%), with no cases occurring after repair of common trunk, 6 occurring after repair of ventricular septal defect (3.7%), and 6 occurring after repair of atrioventricular septal defect (10.3%). Stepwise logistic regression revealed that resection of muscle bundles (P <.0001), higher bypass temperatures (P <.03), and relief of right ventricular outflow tract obstruction through the right atrium (P <.05) significantly and independently predicted postoperative junctional ectopic tachycardia. CONCLUSIONS: Relief of right ventricular outflow tract obstruction appears to be more important in the causation of junctional ectopic tachycardia than does ventricular septal defect closure, which may explain the higher incidence of this complication after tetralogy of Fallot repair. Muscular resection seems to be more arrhythmogenic than is simple division. Increased traction through the right atrium for relief of right ventricular outflow tract obstruction would fit the hypothesis that enhanced automaticity of the His bundle, the morphologic substrate for junctional ectopic tachycardia, may result from direct trauma or infiltrative hemorrhage of the conduction system. When feasible, techniques avoiding both extensive muscle resection and excessive traction should be applied during resection of right ventricular outflow tract obstruction.

Adolescent↗
PubMed2000

Anomalous origin of the left coronary artery from the pulmonary artery: Successful surgical strategy without assist devices.

The objective of this review was to analyze a surgical strategy for children with anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) where aortic implantation was successful without the use of extracorporeal membrane oxygenation (ECMO) or left ventricular assist device (LVAD). From 1989 through 1999, 16 consecutive children underwent aortic implantation for ALCAPA. Median age was 0.45 years. Surgical strategy included bicaval venous cannulation, LV vent, moderate systemic hypothermia (28 degrees C), antegrade cardioplegia with pulmonary artery (PA) occlusion, PA transection, aortic implantation with a large "button" of PA, PA reconstruction with pericardium, intraoperative transesophageal echocardiography, and inotropic support with dopamine, dobutamine, and milrinone. All patients survived. No patient was placed on ECMO or LVAD. Mean cardiopulmonary bypass (CPB) time was 152 +/- 41 minutes. Mean aortic cross-clamp time was 46 +/- 13 minutes. Mean time from cross-clamp removal to CPB off ("weaning" time) was 58 +/- 20 minutes. One patient had delayed sternal closure. Only 2 patients required more than 10 &mgr;g/kg/minute of dopamine and dobutamine. Mean hospital stay was 29 +/- 25 days. One patient required outpatient inotropic support for 5 months. Although ECMO or LVAD may be necessary for some ALCAPA patients, we describe a surgical strategy of aortic implantation that was successful without the use of assist devices. Copyright 2000 by W.B. Saunders Company

Journal Article↗