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Biomedical subjects

C Mavroudis

Publications and source records attributed to C Mavroudis.

At least 91 records · Page 5Linked to original sources

Normal left ventricular muscle mass and mass/volume ratio after pediatric cardiac transplantation.

BACKGROUND: The adaptive growth of the transplanted heart within the growing child may contribute to long-term cardiac performance. The ability to achieve increased ventricular volume and appropriate muscle mass in the face of immunosuppression and cardiac denervation has not been studied. We previously reported normal left ventricular (LV) volume growth over a 3-year period after cardiac transplantation. This study was designed to assess changes in LV mass and mass/volume ratio and their relation to LV end-diastolic pressure (LVEDP) 1 to 4 years after cardiac transplantation. METHODS AND RESULTS: Cardiac transplantation was performed in 18 patients, age 7 days to 18 years (median, 3.7 years). The indications for cardiac transplantation were cardiomyopathy (8 patients), hypoplastic left heart syndrome (7 patients), and postoperative structural congenital heart disease with ventricular failure (3 patients). The mean follow-up was 48 months, with a range from 29 to 70 months. Serial annual catheterizations were performed after 1 year (16 patients), 2 years (18 patients), 3 years (15 patients), and 4 years (8 patients). Cardiac index (Fick), LVEDP (baseline and after 10-mL/kg saline infusion delivered over 5 minutes), and systemic vascular resistance (SVR) were measured. LV diastolic volume index (LVDVI), LV mass index, and mass/volume ratio were determined angiographically according to the method of Lange and Rackley. The data were analyzed by repeated-measures ANOVA. Least-squares means and group SEM were calculated. No change in cardiac index, SVR, or baseline LVEDP was noted. The LVEDP doubled after fluid challenge, suggesting a restrictive process. The LVDVI remained near 60 mL/m2. The LV mass/volume ratio remained one. CONCLUSIONS: Appropriate increases in muscle mass occurred after cardiac transplantation, preserving normal mass/volume ratios despite somatic growth deficits associated with immunosuppressive therapy and denervation of the donor heart.

Body Surface Area↗

Failure of the Hemashield extension in right ventricle-to-pulmonary artery conduits.

Between 1989 and 1991, 17 children underwent 18 right ventricle-to-pulmonary artery conduit placement operations using a composite of an aortic or pulmonary valved homograft and a Hemashield extension to the ventricle. Hemashield is a collagen-coated knitted Dacron graft with excellent compliance and hemostatic properties. Diagnoses included tetralogy of Fallot with pulmonary atresia (7), truncus arteriosus (6), and complex transposition of the great arteries (4). Mean age at conduit placement was 4.9 +/- 4.2 years, and all patients survived. At a mean follow-up of 14 +/- 4 months, postoperative Doppler echocardiographic gradients between the ventricle and pulmonary artery ranged from less than 20 to 60 mm Hg. At cardiac catheterization 13 +/- 3 months postoperatively (6 patients), the systolic pressure gradient across the conduits ranged from 14 to 90 mm Hg (mean gradient, 59 +/- 29 mm Hg). Conduit obstruction, when present, was demonstrated angiographically to be in the Hemashield portion and led to early conduit replacement six times in 5 patients (33% of operations) within 10 to 18 months (mean time, 14 months) after insertion of the original conduit. Pathologic examination of the explanted conduits revealed the obstruction to be a thick neointimal peel that was impossible to separate from the Hemashield graft. Failure of the Hemashield as an extension for ventricle-to-pulmonary artery conduits secondary to accelerated neointimal formation has led us to abandon its use in clinical practice.

Adolescent↗

Restrictive ventricular septal defect: how small is too small to close?

Historically, indications for ventricular septal defect closure have included congestive heart failure, pulmonary hypertension, aortic insufficiency with or without aortic valve prolapse, and prior bacterial endocarditis. However, controversy exists as to how the lifetime risk of an isolated, nonoperated restrictive ventricular septal defect compares with the risk of surgical closure in an asymptomatic child. Between 1980 and 1991, cardiac catheterization and elective ventricular septal defect closure (age > 1 year, pulmonary to systemic flow ratio < 2.0) were performed in 141 patients aged 1 to 23 years (mean age, 6.1 +/- 4.7 years). Mean systolic pulmonary artery pressure was 26.9 +/- 13.0 mm Hg, and mean pulmonary to systemic flow ratio was 1.6 +/- 0.3. Aortic valve prolapse was present in 63 patients (45%), aortic insufficiency was present in 25 (18%), and 5 (3.5%) had prior bacterial endocarditis. There were no early or late deaths or major morbidity. No patient required a ventriculotomy to accomplish ventricular septal defect closure. Mean postoperative intensive care unit stay was 1.3 +/- 0.9 days, and mean hospital stay was 5.5 +/- 1.9 days. There were no instances of permanent complete atrioventricular dissociation, reoperations for bleeding, postoperative wound infections, or reoperations for residual or recurrent ventricular septal defect. These improved results justify a reevaluation of historic indications for ventricular septal defect closure.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

Giant popliteal false aneurysm in an 8-year-old child.

Aneurysms of the arterial system are rare in children. Aneurysms of the popliteal artery are extremely rare in the pediatric population; the majority of these occur after penetrating trauma. The authors report the presentation, evaluation, and successful surgical repair of a giant popliteal false aneurysm found in an 8-year-old girl presumably secondary to blunt trauma.

Aneurysm, False↗

Captopril reduces graft coronary artery disease in a rat heterotopic transplant model.

BACKGROUND: Transplant coronary artery disease (CAD) is characterized by severe myointimal proliferation causing vascular stenosis. Nontransplant vascular injury models have shown that angiotensin converting enzyme (ACE) inhibitors reduce myointimal proliferation and preserve lumen integrity. We examined the effect of the ACE inhibitor captopril on graft CAD in a Lewis to F344 rat heterotopic cardiac transplantation model. METHODS AND RESULTS: Twenty-five control rats (group 1) were observed without captopril administration after heterotopic cardiac transplantation, and the other 19 rats (group 2) were administered captopril (50 mg/kg per day in drinking water) after heart transplantation. Graft survival 3 months after transplantation was significantly (P < .02) higher in group 2 (18 of 19, 95%) than that in group 1 (16 of 25, 64%). Cellular rejection grades of the heart allografts were significantly higher in group 1 than those in group 2 both at 3 months (grades, 2.5 +/- 0.4 vs 1.3 +/- 0.7; P < .01) and 6 months (grades, 2.4 +/- 0.9 vs 0.8 +/- 0.5; P < .05) after transplantation. The grades of graft CAD (vascular rejection) were also significantly higher in group 1 than those in group 2 both at 3 months (grades, 2.3 +/- 0.7 vs 0.9 +/- 0.9; P < .05) and 6 months (grades, 3.0 +/- 0.9 vs 0.9 +/- 0.3; P < .01) after transplantation. The cardiac allographs in group 2 showed minimal intimal proliferation, intact elastic laminae, and reduced smooth muscle cell proliferation. CONCLUSIONS: These results suggest that the ACE inhibitor captopril may be effective in prevention of accelerated graft CAD.

Animals↗

Biventricular repair of hypoplastic right ventricle assisted by pulsatile bidirectional cavopulmonary anastomosis.

The right ventricle in patients with severe outflow obstruction or atresia and a small tricuspid valve often remains too hypoplastic even after optimal palliation to tolerate biventricular repair with closure of the atrial septal defect. In these patients, nonpulsatile cavopulmonary (Glenn) anastomosis has traditionally facilitated biventricular repair. In 1989, Billingsley and associates reported the addition of a bidirectional cavopulmonary anastomosis to the definitive biventricular repair in patients with hypoplastic right ventricle, pulmonary atresia, and intact ventricular septum. The atrial septal defect was left open with an adjustable snare for later closure. We report five patients with hypoplastic right ventricle (mean diastolic volume 48.4%, mean stroke volume 40.2% of predicted value) who had the atrial septal defect closed at the time of the biventricular repair. Four patients, who had the bidirectional cavopulmonary anastomosis supplementing the biventricular repair, had no evidence of excessive right atrial or superior vena cava hypertension postoperatively. One patient, who had atypical tetralogy of Fallot with tricuspid stenosis, developed recurrent pericardial tamponade and marked hepatomegaly following conventional tetralogy repair with closure of the atrial septal defect. These complications were controlled with the addition of bidirectional cavopulmonary anastomosis 2 months later. Postoperative hemodynamic or Doppler studies in these patients revealed pulsatile flow in the entire pulmonary artery system, including the artery distal to the Glenn anastomosis. This modification of biventricular repair allows primary closure of the atrial septal defect and provides pulsatile arterial flow in the entire pulmonary artery, even when the right ventricle is significantly hypoplastic.

Adult↗

Surgical management of infective endocarditis in children.

Infective endocarditis occurs infrequently in the general pediatric population, occurring mostly in patients with congenital heart disease. This study reviews our surgical experience with infective endocarditis based on a policy of aggressive intervention, conservative operative debridement, and creative reconstruction options using pericardium and prosthetic heart valves. From 1982 to 1989, 16 patients, 3 weeks to 16 years of age, underwent 19 intracardiac operations for infective endocarditis therapy at Kosair Children's Hospital. Eight (42%) were for resection of vegetations alone; an additional 11 operations (58%) involved more extensive debridements requiring either valve replacement or valvuloplasty using pericardium for exclusion of an abscess cavity, closure of a fistula, or for valve repair. Operative mortality was 25% (4 patients) and related to preoperative disease severity. There was one late death. Offending organisms included Staphylococcus species (31%), Haemophilus influenzae (13%), pneumococcus (5%), gram-negative organisms (13%), and Candida (13%); no organism grew on culture in 25%. We conclude that aggressive surgical exploration in patients with infective endocarditis is indicated and often requires resection of vegetations alone. More extensive procedures should preserve as much valvular tissue as possible. Pericardium is useful for reconstruction after debridement.

Adolescent↗

Echocardiography for evaluating anatomic repair of transposition of the great arteries.

Fifteen survivors of a single-stage anatomic correction of complete transposition of the great arteries performed at a mean age of 1 month were studied by cross-sectional echocardiography, conventional Doppler echocardiography, Doppler color flow mapping, and catheterization at mean of 10 months after surgery. Small aortic regurgitant jets were documented by angiography and Doppler color flow mapping in seven patients. A trivial supravalvular pulmonary gradient was present in seven patients and a mild to moderate gradient in three. Pulmonary artery flow velocities correlated well with those measured at cardiac catheterization (r = 0.96, standard error of the estimate = 2.6 mm Hg). The present study suggests that combined cross-sectional echocardiography, conventional Doppler echocardiography, and Doppler color flow mapping can be used in the follow-up of patients who have had anatomic repair of transposition of the great arteries, reducing the need for repeated postoperative cardiac catheterizations.

Blood Flow Velocity↗

Ventricular volume growth after cardiac transplantation in infants and children.

BACKGROUND: Intermediate-term survival after pediatric cardiac transplantation continues to improve. However, little is known about cardiac function and especially ventricular growth in young patients after cardiac transplantation. The purpose of this study was to evaluate serially the hemodynamics, left ventricular (LV) volume, and ventricular function after cardiac transplantation in infants and children. METHODS AND RESULTS: Indications for cardiac transplantation were dilated cardiomyopathy (eight patients), hypoplastic left heart syndrome (six patients), and postoperative structural congenital heart disease (three patients). The age at time of transplant ranged from 7 days to 15 years (median, 3.5 years). The mean follow-up was 30.3 months (range, 13-46 months). Serial annual cardiac catheterizations were performed 1 year (17), 2 years (15), and 3 years (seven) after transplant. Measurements included right and left heart pressures, cardiac index, and LV volume and ejection fraction (Lange). Cumulative results (expressed as mean +/- SD) were pulmonary artery pressure, 14.9 +/- 3.2 mm Hg; LV end-diastolic pressure, 7.7 +/- 2.6 mm Hg; cardiac index, 3.5 +/- 0.52 l/min.m-2; and pulmonary vascular resistance, 2.02 +/- 0.76 units/m2. LV end-diastolic volume increased as patients grew, so that left ventricular end-diastolic volume remained 90 +/- 14% of that predicted for body surface area. The ejection fraction was 99 +/- 6% of that predicted. There was no evidence of chronic rejection by endomyocardial biopsy. No accelerated coronary artery atherosclerosis was identified. CONCLUSIONS: Serial studies in these young patients demonstrate normal hemodynamics and LV function after cardiac transplantation. Cardiac transplantation is associated with normal LV volume growth despite immunosuppression and denervation.

Adolescent↗

Fenestrated Fontan with delayed catheter closure. Effects of volume loading and baffle fenestration on cardiac index and oxygen delivery.

BACKGROUND. The fenestrated Fontan operation has been applied to high-risk patients with univentricular hearts, resulting in improved survival. The purpose of this study was to determine the hemodynamic factors responsible for these improved results. METHODS AND RESULTS. We performed the fenestrated Fontan operation in 17 high-risk patients with univentricular hearts (median age, 3 years; age range, 1.2-25 years). High-risk characteristics were depressed ventricular function and/or hypertrophy (n = 12), atrioventricular valve insufficiency (n = 5), pulmonary artery distortion (n = 6), elevated pulmonary vascular resistance (> 2 units/m2) (n = 4), previously failed Fontan operation (n = 2), or associated Wolff-Parkinson-White syndrome (n = 1). Intraoperative hemodynamic measurements (n = 8) included cardiac index (by aortic flow probe), peripheral arterial O2 saturations, and left and right atrial pressures during inflow occlusion, followed by volume loading with open versus closed fenestration. Mean baffle fenestration was 3.5 mm (range, 2.7-5.0 mm). Multiple regression analysis (cardiac index versus atrial pressure) revealed cardiac index was greater with open than with closed fenestration (p < 0.001) during volume loading. Oxygen delivery (cardiac index multiplied by oxygen content) was also greater with open than with closed fenestration (p < 0.001). Survival was 100% with a mean follow-up of 10.4 months; pleural drainage was high in two patients. Subsequent transcatheter fenestration closure resulted in increased O2 saturation (87 +/- 1% to 96 +/- 0.3%, p < 0.05). CONCLUSIONS. The fenestrated Fontan operation improves survival in high-risk patients by increasing cardiac index and maintaining oxygen delivery, despite mild arterial O2 desaturation. Subsequent transcatheter fenestration closure can be performed after hemodynamic assessment.

Cardiac Catheterization↗

Pulmonary artery sling. Results of surgical repair in infancy.

Pulmonary artery sling is a rare congenital vascular anomaly in which the left pulmonary artery originates from the right pulmonary artery and encircles the right main-stem bronchus and distal trachea before entering the hilum of the left lung. This causes compression of the trachea and right main-stem bronchus, and most infants with this anomaly have severe respiratory distress within the first year of life. Between 1953 and 1990 12 infants (nine male, three female) underwent surgical repair of pulmonary artery sling. Ages ranged from 8 days to 9 months (mean age 5 months). Bronchoscopic examination was performed in all patients. Complete tracheal rings were the most common associated lesion (five patients). Nine patients had pulmonary angiography. Most recently, computed tomography and magnetic resonance imaging have been used to diagnose pulmonary artery sling and associated complete tracheal rings when present. Surgical repair consisted of transection of the left pulmonary artery at its origin and implantation into the main pulmonary artery anterior to the trachea via right thoracotomy (one), left thoracotomy (six), or median sternotomy (five). Three patients had simultaneous pericardial patch tracheoplasty for complete tracheal rings. There were no operative deaths. Two late deaths occurred, at 7 months and 2.5 years postoperatively. Of 10 long-term survivors nine have had postoperative studies to determine the patency of the left pulmonary artery. Seven anastomoses were patent (78%). Pulmonary artery sling can be repaired in infancy with low operative mortality and excellent long-term patency of the left pulmonary artery by dividing the left pulmonary artery and implanting it into the main pulmonary artery anterior to the trachea. Simultaneous pericardial patch tracheoplasty should be performed if complete tracheal rings are associated. We recommend repair at the time of diagnosis with median sternotomy and extracorporeal circulation.

Congenital Abnormalities↗

Anomalous origin of the left coronary artery. A twenty-year review of surgical management.

Children with anomalous origin of the left coronary artery from the pulmonary artery are at risk for myocardial infarction and death. Surgical management of this condition in children has evolved significantly during the past 20 years. Between 1970 and 1990, a total of 20 of these patients underwent surgical intervention at two institutions. Age at operation ranged from 3 weeks to 11 years (mean, 26 months). Twelve patients had congestive heart failure, three were in cardiogenic shock, and two had cardiac murmurs. Operative techniques included ligation (n = 9), subclavian artery anastomosis (n = 5), aortic implantation (n = 3), internal mammary artery anastomosis (n = 1), intrapulmonary tunnel from aortopulmonary window to coronary artery (n = 1), and cardiac transplantation (n = 1). The three deaths in the series occurred at 3 weeks, at 2 months, and at 9 years after ligation. There have been no deaths after establishment of a two coronary artery system or after transplantation. Two of the five patients who had subclavian artery anastomosis to the anomalous coronary artery have severe anastomotic stenosis and collateralization. For patients with anomalous origin of the left coronary artery from the pulmonary artery, we recommend direct aortic implantation of the anomalous coronary artery at the time of diagnosis. Intrapulmonary tunnel from aortopulmonary window to coronary artery, or aorta-coronary bypass with internal mammary artery are recommended for children in whom aortic implantation is not anatomically feasible. Left coronary artery ligation is not indicated for these patients; those who have survived ligation should be considered for elective establishment of a two coronary artery system because of the risk of late death.

Anastomosis, Surgical↗

Ventricular septal defect with tricuspid pouch with and without transposition. Anatomic and surgical considerations.

In a 10-year review, patients operated on for ventricular septal defect and tricuspid valve pouch were divided into two groups, because the effect of the tricuspid valve pouch is influenced by which ventricle has the higher pressure. Group I comprised patients with ventricular septal defect without transposition of the great arteries and group II, ventricular septal defect with transposition. In 72 of 392 group I patients, the septal tricuspid valve leaflet was incised to expose the edges of the hidden ventricular septal defect to accomplish proper anatomic repair. Forty-eight patients had a tricuspid valve pouch, the diagnosis being established by angiography, echocardiography, or at operation. Ages at operation ranged from 5 months to 22 years and the pulmonary-systemic flow ratio ranged from 1 to 3.4, with 16 being less than 1.5. In one patient the pouch produced a 40 mm Hg pressure gradient in the right ventricular outflow tract. At operation, through a transatrial approach, the tricuspid valve pouch was opened radially, the actual ventricular septal defect patched, and the tricuspid valve leaflet repaired. There were no deaths, no significant intraoperative or postoperative morbidity, and no tricuspid valve dysfunction. The average postoperative hospital stay was 4.8 days. In group II, six of 83 patients operated on for transposition with ventricular septal defect had significant left ventricular outflow tract obstruction from the tricuspid valve pouch. Five of six had a Mustard procedure, two requiring a left ventricular-pulmonary artery conduit, and in two of the six the ventricular septal defect was closed through the pulmonary artery. One patient had heart transplantation after a Mustard repair and tricuspid valve replacement. The sixth patient in group II had a successful arterial switch at 9 years of age, after the presence of left ventricular outflow tract obstruction was proved to be due to the pouch. The presence of a tricuspid valve pouch in group I may lead the surgeon to close false small openings produced by the pouch rather than the actual ventricular septal defect. Incising the pouch is safe and essential for proper exposure and secure closure of the true defect. In group II, the systemic right ventricular pressure can push the pouch into the left ventricular outflow tract, causing significant obstruction, and may contribute to tricuspid valve insufficiency after atrial baffle repair. Arterial switch is preferred because it returns the obstructive tricuspid valve pouch and abnormal tricuspid leaflet to the lower pressure pulmonic right ventricle.

Child↗

Emergency aortocoronary bypass after failed angioplasty.

One thousand two hundred fourteen percutaneous transluminal coronary angioplasties were performed over a 38-month period. Sixty patients required immediate emergency coronary artery bypass grafting after angioplasty failure; 7 of these had evidence of acute myocardial infarction before angioplasty and were excluded from the study. Of the 53 patients remaining, 27 (51%) had electrocardiographic and enzyme evidence of postoperative myocardial infarction. Two patients died (4%), and 10 had postoperative complications (19%). No statistical significance was noted comparing age, sex, incidence of prior myocardial infarction or myocardial dysfunction, time for revascularization, or average number of grafts completed in those with single-vessel (n = 21) versus multiple-vessel (n = 32) coronary artery disease. Postoperatively, those with multiple-vessel disease required intraaortic balloon pump support (p = 0.06) and antiarrhythmic medications more frequently than single-vessel patients (p less than 0.01) and had a higher complication rate (p less than 0.05). Although not reaching statistical significance, the data also suggest a higher death and postoperative myocardial infarction rate in patients with multiple-vessel disease. Emergency coronary artery bypass grafting after failed percutaneous transluminal coronary angioplasty carries a higher morbidity and mortality than elective coronary artery bypass grafting, particularly for patients with multiple-vessel coronary artery disease.

Aged↗

Pericardial patch tracheoplasty for severe tracheal stenosis in children: intermediate results.

Between 1982 and 1990, 15 children have undergone pericardial patch tracheoplasty, 13 for complete tracheal rings and 2 for acquired tracheal stenosis. Eleven had complete tracheal rings from the thoracic inlet or the cricoid to the carina. Diagnosis was by bronchoscopy (15), computed tomography (10), and magnetic resonance imaging (3). As first described by Idriss in 1984, the surgical technique uses a median sternotomy approach, extracorporeal circulation, bronchoscopic guidance, and the use of pericardium as a tracheal patch. There was one perioperative death of mediastinitis (operative survival, 93%). There were two late deaths caused by complications of tracheostomy (1) and direct laryngoscopy and bronchoscopy (DLB) (1). Follow-up is complete in 12 intermediate-term survivors and ranges from 0.4 to 8.2 years (mean, 4.2 +/- 2.9 years). Five children required multiple DLBs with dilation and excision of granulation tissue; one of these patients underwent tracheoplasty revision 5 months after the initial procedure for residual tracheal rings, and four of these children have had tracheostomies, two temporary and two currently (4 months, 7 years). Seven children had widely patent tracheas observed at follow-up DLB with little or no residual stenosis after tracheoplasty. All survivors are currently asymptomatic, except for the two children with tracheostomies. Pericardial patch tracheoplasty offers effective therapy with relatively low operative mortality for infants and children with severe long segment tracheal stenosis. On intermediate-term follow-up, nearly all survivors are essentially free of symptoms of residual tracheal stenosis.

Child, Preschool↗

Surgical management of the conal (supracristal) ventricular septal defect.

Surgical management of the conal (supracristal) ventricular septal defect differs significantly from the management of the perimembranous (infracristal) ventricular septal defect. The absence of a portion of the conal septum can lead to prolapse of the right cusp of the aortic valve, which predisposes these patients to aortic insufficiency. Between January 1980 and December 1989, 36 children with conal ventricular septal defect underwent intracardiac repair. Diagnosis was by echocardiography, cardiac catheterization, and intraoperative exploration. Preoperative evaluation showed that 26 patients (72%) had aortic valve prolapse and 16 (44%) had aortic insufficiency. Pulmonary-to-systemic flow ratios ranged from 1:1 to 3.5:1 (mean 2.0:1.0). Ten patients (27%) were believed to have clinical congestive heart failure. Age at the time of operation ranged from 2 weeks to 18 years (mean 5.5 years). Operative exposure was through the pulmonary artery (26), aorta (4), right ventricle (3), or right atrium (3). Simultaneous aortic valve suspension for aortic insufficiency was performed in four patients. Operative survival was 100%. Follow-up is complete in all patients and ranges from 0.5 to 9 years (mean 4.3 years). All patients are in normal sinus rhythm. No residual ventricular septal defects have been identified. Twenty-three of 36 patients (64%) have no evidence of aortic insufficiency; 12 of 36 (33%) have trivial or mild aortic insufficiency. One patient with initial severe aortic insufficiency underwent repeat aortic valvuloplasty 3 years after ventricular septal defect closure and aortic valve suspension. No patients have required aortic valve replacement. Surgical management of the conal ventricular septal defect differs from that of the perimembranous ventricular septal defect in two critical aspects. The operative approach should be through the pulmonary artery. This allows the best exposure of the remaining conal septum and the pulmonary and aortic valve leaflets, facilitating closure of the defect without injury to the valves or conduction system. Conal ventricular septal defects should undergo early closure, regardless of shunt volume, to prevent progressive aortic insufficiency.

Adolescent↗