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Biomedical subjects

F L Hanley

Publications and source records attributed to F L Hanley.

At least 37 records · Page 2Linked to original sources
PubMed2000

Issues and outcomes in the management of supravalvar aortic stenosis.

BACKGROUND: Supravalvar stenosis of the aorta is an uncommon congenital cardiac anomaly that involves not only the supravalvar aorta but the entire aortic root. Despite considerable attention to the importance of maintaining the integrity of the aortic root during supravalvar reconstruction, there has been little focus on the management of other components of the aortic root and left ventricular outflow tract, including the aortic valve, subvalvar region, and coronary arteries. METHODS: We reviewed the records of 36 consecutive patients with supravalvar aortic stenosis who underwent repair from 1992-1998 (median age, 4 years). Discrete stenosis was present in 29 patients, whereas the remaining 7 had the diffuse form of the disease. Associated anomalies of the aortic root and adjacent structures were present in 23 patients. The median pressure gradient across the left ventricular outflow tract was 70 mm Hg. Supravalvar stenosis was relieved by extended aortoplasty with a Y-shaped patch in 18 patients, resection of the stenotic segment of ascending aorta at the sinotubular junction with end-to-end anastomosis of the ascending aorta in 7, the Ross procedure in 4, and other techniques in 7. Additional procedures included aortic valvuloplasty in 10 patients, resection of subvalvar stenosis in 11, and procedures on the coronary arteries in 2. RESULTS: There was 1 perioperative death, and no reoperations or other significant complications. During follow-up (median 33 months), there were no deaths and 3 reoperations for replacement of the aortic valve with a pulmonary autograft (n = 1) or mechanical prosthesis (n = 2). The median pressure gradient across the left ventricular outflow tract was 10 mm Hg. CONCLUSIONS: In patients with supravalvar aortic stenosis, abnormalities of the aortic valve, subaortic region, and coronary arteries are frequently present as well. Management of these issues is as critical to the long-term outcome of these patients as reconstruction of the supravalvar aorta. Aggressive valvuloplasty may help decrease the incidence of late aortic valve replacement, whereas the Ross procedure may be a preferable approach in some patients with complex outflow tract obstruction.

Adolescent↗
PubMed2000

Revision of previous Fontan connections to total extracardiac cavopulmonary anastomosis: A multicenter experience.

BACKGROUND: Conversion to total extracardiac cavopulmonary anastomosis is an option for managing patients with dysfunction of a prior Fontan connection. METHODS: Thirty-one patients (19.9 +/- 8.8 years) underwent revision of a previous Fontan connection to total extracardiac cavopulmonary anastomosis at four institutions. Complications of the previous Fontan connection included atrial tachyarrhythmias (n = 20), progressive heart failure (n = 17), Fontan pathway obstruction (n = 10), effusions (n = 10), pulmonary venous obstruction by an enlarged right atrium (n = 6), protein-losing enteropathy (n = 3), right atrial thrombus (n = 2), subaortic stenosis (n = 1), atrioventricular valve regurgitation (n = 3), and Fontan baffle leak (n = 5). Conversion to an extracardiac cavopulmonary connection was performed with a nonvalved conduit from the inferior vena cava to the right pulmonary artery, with additional procedures as necessary. RESULTS: There have been 3 deaths. Two patients died in the perioperative period of heart failure and massive effusions. The third patient died suddenly 8 months after the operation. All surviving patients were in New York Heart Association class I (n = 20) or II (n = 7), except for 1 patient who underwent heart transplantation. Early postoperative arrhythmias occurred in 10 patients: 4 required pacemakers, and medical therapy was sufficient in 6. In 15 patients, pre-revision arrhythmias were improved. Effusions resolved in all but 1 of the patients in whom they were present before revision. The condition of 2 patients with protein-losing enteropathy improved within 30 days. CONCLUSIONS: Conversion of a failing Fontan connection to extracardiac cavopulmonary connection can be achieved with low morbidity and mortality. Optimally, revision should be undertaken early in symptomatic patients before irreversible ventricular failure ensues.

Adolescent↗
PubMed2000

Reinterventions after repair of common arterial trunk in neonates and young infants.

OBJECTIVES: To determine rates of reintervention after repair of common arterial trunk in the neonatal and early infant periods. BACKGROUND: With improving success in the early treatment of common arterial trunk, the need for reinterventional procedures in older children, adolescents and adults will become an increasingly widespread concern in the treatment of these patients. METHODS: We reviewed our experience with 159 infants younger than four months of age who underwent complete primary repair of common arterial trunk at our institution from 1975 to 1998, with a focus on postoperative reinterventions. RESULTS: Of 128 early survivors, 40 underwent early reinterventions for persistent mediastinal bleeding or other reasons. During a median follow-up of 98 months (range, 2 to 235 months), 121 reinterventions were performed in 81 patients. Actuarial freedom from reintervention was 50% at four years, and freedom from a second reintervention was 75% at 11 years. A total of 92 conduit reinterventions were performed in 75 patients, with a single reintervention in 61 patients, 2 reinterventions in 11 patients and 3 reinterventions in 3 patients. Freedom from a first conduit reintervention was 45% at five years. The only independent variable predictive of a longer time to first conduit replacement was use of an allograft conduit at the original repair (p = 0.05), despite the significantly younger age of patients receiving an allograft conduit (p < 0.001). Reintervention on the truncal valve was performed on 22 occasions in 19 patients, including 21 valve replacements in 18 patients and repair in 1, with a freedom from truncal valve reintervention of 83% at 10 years. Surgical (n = 29) or balloon (n = 12) reintervention for pulmonary artery stenosis was performed 41 times in 32 patients. Closure of a residual ventricular septal defect was required in 13 patients, all of whom underwent closure originally with a continuous suture technique. Eight of 16 late deaths were related to reintervention. CONCLUSIONS: The burden of reintervention after repair of common arterial trunk in early infancy is high. Although conduit reintervention is inevitable, efforts should be made at the time of the initial repair to minimize factors leading to reintervention, including prevention of branch pulmonary artery stenosis and residual interventricular communications.

Actuarial Analysis↗
PubMed2000

Elective primary repair of acyanotic tetralogy of Fallot in early infancy: overall outcome and impact on the pulmonary valve.

OBJECTIVES: We sought to determine if early primary repair of acyanotic tetralogy of Fallot (ToF) can be performed safely with low requirement for transannular patching (TAP) and thereafter allow normal right ventricular outflow tract (RVOT) growth. BACKGROUND: Early primary repair of ToF normalizes intracardiac flow patterns, which may allow subsequent normal RVOT growth. Traditionally repair is deferred until symptoms occur or children are deemed of adequate size for operative risk to be acceptable because of a perceived increased requirement for TAP in small infants. METHODS: Between July 1992 and March 1999, 42 acyanotic infants aged 4 to 87 days (median 62) and weight 2.6 to 6.6 kg (median 4.55) underwent complete repair of ToF. Pulmonary annulus measured 4 to 10.5 mm (median 6.5) with "z-value" of-5.6 to +3.0 (median -1.9). RVOT reconstruction was tailored to each patient; pulmonary valvotomy was performed in 26, main pulmonary arterioplasty in 22, and infundibular patching in 2. Only 10 (24%) required TAP. RESULTS: Postoperative RVOT gradient was 0 to 30 mm Hg (median 10) and pRV/pLV ratio 0.3 to 0.6 (median 0.44). Pulmonary insufficiency was trivial/mild. There were no deaths. Junctional ectopic tachycardia developed in seven; only one required treatment. ICU stay was 2 to 14 days (median 4) and hospital stay 4 to 22 days (median 7). At follow-up 12 to 64 months later (median 38) there were no deaths. One child required reoperation for recurrent RVOT obstruction and two required balloon pulmonary arterioplasty. Follow-up RVOT gradient was 0 to 36 mm Hg (median 12), unchanged from early postoperative condition, and median z-value was -1.2 (-2.8 to +2.5); pulmonary insufficiency remained trivial/mild. CONCLUSIONS: Complete repair of acyanotic ToF can be performed in early infancy with low morbidity and mortality and low requirement for TAP. Though results are not statistically significant, early repair may allow normal RVOT growth thereafter.

Coronary Circulation↗
PubMed2000

Cardiac surgery in infants with very low birth weight.

Congenital heart defects in low birth weight infants are typically managed with supportive therapy or palliative surgery, and definitive repair is delayed. However, the morbidity of such an approach has been shown to be high. Recent reports emphasize early surgical repair with good results in low birth weight and premature babies. However, there are no data on the outcomes in infants with very low birth weight (<1,500 g). Since 1990, the authors performed complete repair of congenital heart defects (other than isolated patent ductus arteriosus) in 20 infants weighing 1,500 g or less. Defects included aortic coarctation (n = 6), ventricular septal defect (n = 5), tetralogy of Fallot (n = 2), transposition of great arteries (n = 2), truncus arteriosus (n = 2), total anomalous pulmonary venous return (n = 1), double outlet right ventricle (n = 1), and pulmonary atresia with intact ventricular septum (n = 1). Preoperative morbidity was more common in patients who were referred late for corrective surgery. Modification of techniques of neonatal cardiopulmonary bypass were used. There were 2 early deaths (10%) caused by foot gangrene (n = 1), and pulmonary complications (n = 1). No patient had evidence of postbypass intracranial hemorrhage. At a median follow-up of 40 months, there was 1 late death, and 4 patients underwent a total of 5 surgical and catheter reinterventions. There was no evidence of neurological sequelae attributable to surgery. In most cases, delaying repair of congenital heart defects in low and very low birth weight infants does not confer any benefit and is associated with a higher incidence of preoperative morbidity. Complete repair of both simple and complex congenital heart lesions can be performed successfully in such patients with good early and medium-term results. Postoperative growth after repair approximates the normal growth curve for low birth weight infants without congenital heart disease. It is recommended that with few exceptions, such infants, especially when symptomatic, undergo early surgical correction rather than prolonged medical management or other forms of palliation.

Abnormalities, Multiple↗
PubMed2000

Familial absent pulmonary valve syndrome without deletions of chromosome 22q11.

Deletions of chromosome 22q11 are common in patients with tetralogy of Fallot, and in those with absent pulmonary valve syndrome. In this report, we describe a pair of siblings with absent pulmonary valve syndrome, neither of whom had deletions of chromosome 22q11. The finding of familial absent pulmonary valve syndrome without deletion of 22q11 in our patients suggests an alternative genetic basis for this rare condition.

Child, Preschool↗
PubMed2000

Surgical approach to complicated cervical aortic arch: anatomic, developmental, and surgical considerations.

BACKGROUND: Abnormalities of brachiocephalic arterial branching and arch laterality are common in patients with a cervical aortic arch. In addition, structural anomalies of the arch such as obstruction, aneurysms, and tortuosity are found in a significant number of cases. METHODS: Between 1990 and 1998, 6 patients underwent surgery for an obstructed right cervical arch. A significant obstruction was present at the transverse or distal arch in all patients, and was recurrent after previous repair in 2. In 1 patient, there was also a multi-lobed aneurysm of the aortic segment contiguous to the obstruction, and in 2 there was marked tortuosity of the arch. In all cases, the order of origin of the head and neck vessels was abnormal, and obstruction of 1 or more brachiocephalic vessels was found in 3. A vascular ring was present in all patients, with a right aortic arch and aberrant left subclavian artery in 4 patients and a double aortic arch with a dominant right cervical arch in 2. The descending aorta was circumflex (left-sided) in 3 patients. Three patients were repaired through a standard right posterolateral thoracotomy, and 3 through a median sternotomy. Patch augmentation aortoplasty was used in 2 patients, a tube graft from the ascending to descending aorta in 2, end to side anastomosis of the descending aorta to the proximal arch in 1, and direct anastomosis to reconstruct an atretic left-sided component of a double arch in 1. RESULTS: Repair was successful in all cases, with no perioperative complications. At follow-up ranging from 1 to 9 years, all patients were alive and well, with no recurrence of arch obstruction or other significant complications. Fluorescent in situ hybridization revealed microdeletion of chromosome 22q11 in 1 patient (not performed in the others). CONCLUSIONS: Structural anomalies of the arch are relatively common in patients with a cervical aortic arch. Such abnormalities may be the result of hemodynamic conditions and/or abnormal vascular tissue related either to the cervical position of the arch or its embryologic precursors. Given the highly variable anatomy of patients with a complicated cervical aortic arch, surgical considerations will vary in kind.

Adolescent↗
PubMed2000

Coronary arterial size late after the atrial inversion procedure for transposition of the great arteries: implications for the arterial switch operation.

BACKGROUND: Coronary flow reserve in the hypertrophied ventricle is reduced. One contributing factor may be the size of the proximal coronary arteries. In patients who undergo atrial inversion procedures for transposition of the great arteries, the left coronary artery supplies the pulmonary ventricle and may be smaller than the right coronary artery. We hypothesized that the dimensions of the coronary arteries may correlate with symptomatic status after atrial inversion and may be an important factor when these patients are considered for the arterial switch operation. METHODS: The proximal left and right coronary arteries were measured in 9 patients with transposition and failure of the systemic right ventricle after atrial inversion, 10 asymptomatic patients after atrial inversion, and 10 patients with normal hearts. The diameters of the coronary arteries were indexed to body surface area and compared. RESULTS: The absolute and indexed diameters of the right coronary artery were greater in symptomatic patients than in asymptomatic patients (indexed: 3.1 +/- 0.6 vs 2.4 +/- 0.4 mm/m(2), P <.001) or control patients (2.0 +/- 0.3, P <.001), and the absolute diameter of the left coronary artery was smaller (2.9 +/- 0. 7 vs 3.6 +/- 0.5 mm, P =.003 [asymptomatic], 3.6 +/- 0.5 mm, P =.01 [control]). In symptomatic patients, the absolute and indexed diameters of the left coronary artery were smaller than those of the right (indexed: 2.1 +/- 0.6 vs 3.1 +/- 0.6 mm/m(2), P <.001). By contrast, there was no difference in asymptomatic patients (2.2 +/- 0.5 vs 2.4 +/- 0.4 mm/m(2), P =.44), and the left coronary artery was larger in normal control patients (2.2 +/- 0.4 vs 2.0 +/- 0.3 mm/m(2), P <.001). CONCLUSIONS: Differences in the sizes of the proximal coronary arteries may be related to symptomatic status in patients with transposition of the great arteries who have undergone an atrial inversion procedure, as well as to the efficacy of ventricular retraining. When pulmonary artery banding and subsequent arterial switch are considered for patients with a Mustard or Senning procedure and a failing systemic right ventricle, the size of the proximal coronary arteries may be an important factor and should be evaluated with preoperative imaging studies.

Adult↗
PubMed2000

Management and outcomes of delayed sternal closure after cardiac surgery in neonates and infants.

OBJECTIVES: To investigate the efficacy, safety, and patterns of management of open sternotomy and delayed sternal closure in infants who were left with an open sternum after cardiac surgery and to assess these patterns for possible correlation with outcome. DESIGN: Retrospective chart review with statistical analysis. SETTING: Pediatric cardiac surgery service at a regional referral center based in an urban university teaching hospital. PATIENTS: All 128 patients <1 yr of age who were left with an open sternum after cardiac surgery with cardiopulmonary bypass during the 4-yr period from July, 1992 to June, 1996. INTERVENTIONS: Procedures for managing open sternotomy and delayed sternal closure were analyzed retrospectively. No interventions were undertaken for the study. MEASUREMENTS AND RESULTS: Of the 128 patients, 14 (11%) died before sternal closure; delayed sternal closure was performed in the remaining 114. Of these 114, 13 died in the early postoperative period. During sternal closure, significant increases were noted in pulmonary arterial (from 21.1+/-7.6 mm Hg to 26.1+/-6.5 mm Hg; p = .006), left atrial (from 8.4+/-3.4 mm Hg to 11.5+/-3.7 mm Hg; p < .001), and right atrial pressures (from 7.3+/-2.5 mm Hg to 9.8+/-2.5 mm Hg; p < .001). In addition, mean airway pressure (from 7.4+/-2.0 mm Hg to 8.6+/-2.4 mm Hg; p < .001) and peak inspiratory pressure (from 29.3+/-5.4 mm Hg to 31.3+/-5.6 mm Hg; p = .004) increased. Sternal wound infection occurred in one patient. CONCLUSIONS: Delayed sternal closure is an effective approach to the management of neonates and infants at risk for hemodynamic, respiratory, or hemostatic instability early after cardiac surgery. Significant changes in hemodynamics and respiratory variables occur during sternal closure, often requiring adjustment of inotropic and ventilatory management. (Crit Care Med 2000; 28: 1180-1184)

Cardiac Surgical Procedures↗
PubMed2000

Transthoracic intracardiac catheters in pediatric patients recovering from congenital heart defect surgery: associated complications and outcomes.

OBJECTIVES: To characterize transthoracic intracardiac catheter uses and associated morbidities in pediatric patients recovering from congenital heart defect surgery and to identify potential risk factors associated with their use. DESIGN: Prospective data collection and review. SETTING: An 18-bed pediatric intensive care unit (PICU) in a tertiary care university hospital. PATIENTS: All pediatric patients between October 1, 1996, and September 30, 1997, who were recovering from congenital heart defect surgery and had transthoracic intracardiac catheters in place. MEASUREMENTS AND MAIN RESULTS: Catheter use, associated morbidity, necessary interventions, and risk factors for complications of catheter use were identified. During this period, 523 catheters (276 right atrial, 155 left atrial, 68 common atrial, and 24 right ventricular or pulmonary artery catheters) in 351 PICU patients were studied. Mean age was 23.1+/-45.1 months (median, 4.98 months); 138 patients (39.3%) were <3 months old. The rate of occurrence of bleeding with catheter removal (mediastinal output in the hour after removal that was more than twice the previous average hourly output) was 36.7%, and bleeding occurred more frequently with left atrial catheters (47%; odds ratio, 2.0; p < .05). However, interventions after catheter removal were required for only 8.3% (42/504) of catheters removed, and hemodynamic compromise occurred with the removal of only 2.6% (13/504) of catheters. Interventions included fluid resuscitation (35 cases), pleural drainage (three cases), catheter wiring for retention (one case), chest tube suctioning (two cases), and surgical removal (one case). No associated deaths occurred. In a multivariate logistic regression analysis, age <3 months (odds ratio, 4.74), catheter location (left atrial: odds ratio, 4.97; pulmonary artery: odds ratio, 12.48), and platelet count of <50,000 (odds ratio, 8.59) were identified as risk factors associated with a need for intervention after catheter removal (p < .05). Other complications included blood cultures positive for organisms (1.5%), thrombus (0.6%), and catheter nonfunction (10.9%). Prematurity was a risk factor for thrombus and nonfunction. CONCLUSIONS: Use of transthoracic intracardiac catheters in pediatric patients is safe. Young infants and pediatric patients with thrombocytopenia or with catheters in the left atrial or pulmonary artery position have a greater need for interventions after catheter removal, warranting added precautions.

Adolescent↗
PubMed2000

Extracardiac conduit variation of the Fontan procedure.

The ECF operation is designed to improve postoperative outcome by enhancing factors that are critical in optimal functioning of the Fontan circulation, including preservation of ventricular and pulmonary vascular function, avoidance of dysrhythmias, and prevention of stasis and flow turbulence in the Fontan circuit. Preoperative strategies include an early bidirectional Glenn procedure, and avoiding ancillary intracardiac procedures at the time of the Fontan by performing them at the time of the Glenn operation. Operative strategies include minimizing the duration of CPB by performing the conduit to pulmonary artery anastomosis off bypass, using partial instead of full CPB by cannulating the IVC alone, avoiding hypothermia, avoiding cross-clamping of the aorta, avoiding atrial incisions and suture lines, using a tubular conduit to construct the Fontan pathway, making a large conduit to pulmonary artery anastomosis, incorporating the conduit into aggressive pulmonary arterioplasties, and offsetting of the superior and inferior cavopulmonary anastomoses.

Arrhythmias, Cardiac↗
PubMed1999

Congenital obstructive lesions of the right aortic arch.

BACKGROUND: In the setting of normal cardiac situs, a right-sided aortic arch is uncommon. When a right arch does occur, it is typically in conjunction with other congenital cardiovascular anomalies, especially defects with abnormal right ventricular outflow. Congenital obstruction of a right arch, caused by coarctation, interruption, or cervical arch, is extremely rare. METHODS: We reviewed our experience and all reported cases of right aortic arch with coarctation of the aorta, interrupted arch, or obstruction of a cervical arch in the setting of normal cardiac situs and topology. RESULTS: Since 1992, 4 such patients have undergone repair at our institution, including 1 with interrupted arch, 1 with coarctation of a mirror image arch, and 2 with obstruction of a cervical arch. In addition to these 4 patients, 38 others have been described in the published reports: 15 with interrupted arch, 19 with coarctation, and 4 with obstruction of a cervical arch. Associated cardiac defects were uncommon, except for ventricular septal defect in patients with interrupted arch, but abnormalities of the brachiocephalic vessels were frequent. Except for most of the patients with interrupted right arch, the majority of patients described have undergone successful surgical repair. CONCLUSIONS: Although obstructive arch lesions are often grouped together, the etiologies of coarctation of the aorta, interrupted arch, and cervical arch with obstruction almost certainly differ. The rarity of such lesions among patients with right aortic arch may be explained in part by the fact that the fetal hemodynamic conditions associated with persistence of a right arch do not facilitate flow-related arch obstruction. In this review, we discuss these issues in detail, along with specific surgical considerations in the management of obstruction lesions of the right aortic arch.

Aorta, Thoracic↗
PubMed1999

Compression of the central airways by a dilated aorta in infants and children with congenital heart disease.

BACKGROUND: Children with congenital heart disease often experience respiratory symptoms in the preoperative and perioperative periods, which can complicate their management. An uncommon but important cause of respiratory insufficiency in such children is external airway compression. METHODS: We operated on 5 patients (median age, 6 months) with significant respiratory distress attributable to compression of the central airways by a dilated ascending aorta before or after repair of concomitant cardiovascular defects. Four of these patients had right aortic arch and 3 had pulmonary atresia with a ventricular septal defect and major aortopulmonary collaterals. In all patients, aortopexy was performed at the time of operation for the cardiovascular defects (n = 3) or after symptoms developed in the postoperative period (n = 2). The 3 patients in whom airway compression produced symptoms preoperatively also underwent reduction ascending aortoplasty. RESULTS: Symptoms resolved immediately after operation in 3 patients, whereas symptoms persisted in the other 2 patients and tracheostomy was required. At follow-up of 20 months to 5 years, all patients are alive and well, with mild or moderate respiratory symptoms in the 2 patients who required tracheostomy, both of whom were decannulated within 13 months. CONCLUSIONS: External airway compression can cause significant morbidity in patients with congenital heart defects other than vascular rings. In patients with respiratory symptoms in the context of a lesion that involves increased aortic outflow during intrauterine life and consequently, an enlarged ascending aorta, such as tetralogy of Fallot with pulmonary atresia, airway compression should be considered as a cause, especially if a right aortic arch is present or the patient also has pulmonary atresia with a ventricular septal defect and collaterals. Attempts to address this problem surgically may provide substantial relief, but increasing duration of airway compression is likely to lead to tracheal or bronchial malacia and persistent symptoms even after the compression is relieved.

Airway Obstruction↗
PubMed1999

Early results of the extracardiac conduit Fontan operation.

BACKGROUND: Among the modifications of the Fontan operation, the extracardiac approach may offer the greatest potential for optimizing early postoperative ventricular and pulmonary vascular function, insofar as it can be performed with short periods of normothermic partial cardiopulmonary bypass and without cardioplegic arrest in most cases. In this study, we reviewed our experience with the extracardiac conduit Fontan operation, with a focus on early postoperative outcomes. METHODS AND RESULTS: Between July 1992 and April 1997, 51 patients (median age 4.9 years) underwent an extracardiac conduit Fontan operation. Median cardiopulmonary bypass time was 92 minutes and has decreased significantly over the course of our experience. Intracardiac procedures were performed in only 5 patients (10%), and the aorta was crossclamped in only 11 (22%). Intraoperative fenestration was performed in 24 patients (47%). There were no early deaths. Fontan failure occurred in 1 patient who was a poor candidate for the Fontan procedure. Transient supraventricular tachyarrhythmias occurred in 5 patients (10%). Median duration of chest tube drainage was 8 days. Factors significantly associated with prolonged resource use (mechanical ventilation, inotropic support, intensive care unit stay, and hospital stay) included longer bypass time and higher Fontan pressure. At a median follow-up of 1.9 years, there was 1 death from bleeding at reoperation. CONCLUSIONS: The extracardiac conduit Fontan procedure can be performed with minimal mortality and morbidity. Improved results may be related to advantages of the extracardiac approach and improved preservation of ventricular and pulmonary vascular function.

Cardiopulmonary Bypass↗
PubMed1999

Endothelin receptor blockade prevents the rise in pulmonary vascular resistance after cardiopulmonary bypass in lambs with increased pulmonary blood flow.

BACKGROUND: Children with increased pulmonary blood flow may experience morbidity as the result of increased pulmonary vascular resistance after operations in which cardiopulmonary bypass is used. Plasma levels of endothelin-1, a potent vasoactive substance implicated in pulmonary hypertension, are increased after cardiopulmonary bypass. OBJECTIVES: In a lamb model of increased pulmonary blood flow after in utero placement of an aortopulmonary shunt, we characterized the changes in pulmonary vascular resistance induced by hypothermic cardiopulmonary bypass and investigated the role of endothelin-1 and endothelin-A receptor activation in postbypass pulmonary hypertension. METHODS: In eleven 1-month-old lambs, the shunt was closed, and vascular pressures and blood flows were monitored. An infusion of a selective endothelin-A receptor blocker (PD 156707; 1.0 mg/kg/h) or drug vehicle (saline solution) was then begun 30 minutes before cardiopulmonary bypass and continued for 4 hours after bypass. The hemodynamic variables were monitored, and plasma endothelin-1 concentrations were determined before, during, and for 6 hours after cardiopulmonary bypass. RESULTS: After 90 minutes of hypothermic cardiopulmonary bypass, both pulmonary arterial pressure and pulmonary vascular resistance increased significantly in saline-treated lambs during the 6-hour study period (P <.05). In lambs pretreated with PD 156707, pulmonary arterial pressure and pulmonary vascular resistance decreased (P <. 05). After bypass, plasma endothelin-1 concentrations increased in all lambs; there was a positive correlation between postbypass pulmonary vascular resistance and plasma endothelin-1 concentrations (P <.05). CONCLUSIONS: This study suggests that endothelin-A receptor-induced pulmonary vasoconstriction mediates, in part, the rise in pulmonary vascular resistance after cardiopulmonary bypass. Endothelin-A receptor antagonists may decrease morbidity in children at risk for postbypass pulmonary hypertension. This potential therapy warrants further investigation.

Analysis of Variance↗
PubMed1999

Results of 102 cases of complete repair of congenital heart defects in patients weighing 700 to 2500 grams.

BACKGROUND: Published data suggest that low birth weight is a risk factor for poor outcome in corrective surgery for many cardiac defects. Congenital heart defects in low birth weight infants are typically managed with supportive therapy or palliative operations, with definitive repair delayed. The morbidity associated with such approaches is high. METHODS: Since 1990 complete repair of congenital heart defects (other than patent ductus arteriosus) has been performed in 102 infants no larger than 2500 g (median 2100 g, range 700-2500 g), including 16 no larger than 1500 g. Defects included ventricular septal defect (n = 22), tetralogy of Fallot complexes (n = 20), transposition complexes (n = 13), aortic coarctation (n = 12), interrupted arch (n = 10), truncus arteriosus (n = 8), atrioventricular septal defect (n = 6), total anomalous pulmonary venous return (n = 5), and other (n = 6). RESULTS: Preoperative morbidity was more common among patients referred late for surgical correction. There were 10 early deaths (10%) attributable to cardiac failure (n = 4), arrhythmia (n = 1), multiorgan failure (n = 1), sepsis (n = 1), idiopathic coronary artery intimal necrosis (n = 1), foot gangrene (n = 1), and pulmonary hemorrhage (n = 1). No patient had postbypass intracerebral hemorrhage. At follow-up (median 36 months) there were 8 late deaths, and 8 patients underwent 10 reinterventions. There was no evidence of neurologic sequelae attributable to the operation. CONCLUSIONS: In general, delaying repair of congenital heart defects in low birth weight infants does not confer a benefit and is associated with higher preoperative morbidity. Complete repair of both simple and complex lesions can be achieved in such cases with good results. Growth after repair approximates the normal curve for low birth weight infants without heart disease. It is recommended that such infants, especially when they have symptoms, undergo early surgical repair rather than prolonged medical management or other forms of palliation.

Actuarial Analysis↗