David F. Teitel

Balloon Atrial Septostomy Is Associated With Preoperative Stroke in Neonates With Transposition of the Great Arteries

Background— Preoperative brain injury is common in neonates with transposition of the great arteries (TGA). The objective of this study is to determine risk factors for preoperative brain injury in neonates with TGA. Methods and Results— Twenty-nine term neonates with TGA were studied with MRI before cardiac surgery in a prospective cohort study. Twelve patients (41%) had brain injury on preoperative MRI, and all injuries were focal or multifocal. None of the patients had birth asphyxia. Nineteen patients (66%) required preoperative balloon atrial septostomy (BAS). All patients with brain injury had BAS (12 of 19; risk difference, 63%; 95% confidence interval, 41 to 85; P=0.001). As expected on the basis of the need for BAS, these neonates had lower systemic arterial hemoglobin saturation (Sao2) (P=0.05). The risk of injury was not modified by the cannulation site for septostomy (umbilical versus femoral, P=0.8) or by the presence of a central venous catheter (P=0.4). Conclusions— BAS is a major identifiable risk factor for preoperative focal brain injury in neonates with TGA. Imaging characteristics of identified brain injuries were consistent with embolism; however, the mechanism is more complex than site of vascular access for BAS or exposure to central venous catheters. These findings have implications for the indications for BAS, timing of surgical repair, and use of anticoagulation in TGA.

Early and Intermediate Outcomes After Repair of Pulmonary Atresia With Ventricular Septal Defect and Major Aortopulmonary Collateral Arteries Experience With 85 Patients

BACKGROUND Pulmonary atresia with ventricular septal defect (VSD) and major aortopulmonary collaterals (MAPCAs) is a complex lesion with marked heterogeneity of pulmonary blood supply. Traditional management has involved staged unifocalization of pulmonary blood supply. Our approach has been to perform early 1-stage complete unifocalization in almost all patients. METHODS AND RESULTS Since 1992, 85 patients with pulmonary atresia, VSD, and MAPCAs have undergone unifocalization (median age, 7 months). Complete 1-stage unifocalization and intracardiac repair were performed through a midline approach in 56 patients, whereas 23 underwent unifocalization in a single stage with the VSD left open, and 6 underwent staged unifocalization through sequential thoracotomies. There were 9 early deaths. During follow-up (1 to 69 months), there were 7 late deaths. Actuarial survival was 80% at 3 years. Among early survivors, actuarial survival with complete repair was 88% at 2 years. Reintervention on the neo-pulmonary arteries was performed in 24 patients. CONCLUSIONS Early 1-stage complete unifocalization can be performed in >90% of patients with pulmonary atresia and MAPCAs, even those with absent true pulmonary arteries, and yields good functional results. Complete repair during the same operation is achieved in two thirds of patients. There remains room for improvement; actuarial survival 3 years after surgery is 80%, and there is a significant rate of reintervention. These results must be appreciated within the context of the natural history of this lesion: 65% of patients survive to 1 year of age and slightly >50% survive to 2 years even with surgical intervention.

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.

Two-dimensional echocardiographic determination of aortic and pulmonary artery sizes from infancy to adulthood in normal subjects.

The aorta, right pulmonary artery and pulmonary trunk were measured from the 2-dimensional echocardiogram (2-D echo) of 110 normal subjects aged 1 day to 18 years. The vessel diameters were measured from the parasternal short-axis view, the suprasternal long-axis view and the suprasternal short-axis view. Measurements were made at end-systole and at end-diastole and in both an axial and lateral direction where possible. When analyzed with respect to body surface area (BSA), the echocardiographic measurements were linearly related to the square root of the BSA, and there was inequality of variance around the relation. To establish a range of normal values for each vessel dimension, a weighted regression analysis was used to produce estimates of the regression line and a set of tolerance intervals. The systolic vessel dimension was larger than the diastolic vessel dimension and the measurement of a vessel in an axial direction was larger than the measurement of the same vessel in a lateral direction. In general, when a vessel was measured in several views, the largest diameter was obtained using the view that imaged the vessel in cross section. These data on normal values for the echocardiographic measurement of the aorta and pulmonary arteries at different BSAs should be useful for identifying patients with abnormalities in arterial size and for the serial assessment of arterial size in children who have undergone surgical or medical therapy.

Intermediate follow‐up following intravascular stenting for treatment of coarctation of the aorta

Background: We report a multiinstitutional study on intermediate‐term outcome of intravascular stenting for treatment of coarctation of the aorta using integrated arch imaging (IAI) techniques. Methods and Results: Medical records of 578 patients from 17 institutions were reviewed. A total of 588 procedures were performed between May 1989 and Aug 2005. About 27% (160/588) procedures were followed up by further IAI of their aorta (MRI/CT/repeat cardiac catheterization) after initial stent procedures. Abnormal imaging studies included: the presence of dissection or aneurysm formation, stent fracture, or the presence of reobstruction within the stent (instent restenosis or significant intimal build‐up within the stent). Forty‐one abnormal imaging studies were reported in the intermediate follow‐up at median 12 months (0.5–92 months). Smaller postintervention of the aorta (CoA) diameter and an increased persistent systolic pressure gradient were associated with encountering abnormal follow‐up imaging studies. Aortic wall abnormalities included dissections (n = 5) and aneurysm (n = 13). The risk of encountering aortic wall abnormalities increased with larger percent increase in CoA diameter poststent implant, increasing balloon/coarc ratio, and performing prestent angioplasty. Stent restenosis was observed in 5/6 parts encountering stent fracture and neointimal buildup (n = 16). Small CoA diameter poststent implant and increased poststent residual pressure gradient increased the likelihood of encountering instent restenosis at intermediate follow‐up. Conclusions: Abnormalities were observed at intermediate follow‐up following IS placement for treatment of native and recurrent coarctation of the aorta. Not exceeding a balloon:coarctation ratio of 3.5 and avoidance of prestent angioplasty decreased the likelihood of encountering an abnormal follow‐up imaging study in patients undergoing intravascular stent placement for the treatment of coarctation of the aorta. We recommend IAI for all patients undergoing IS placement for treatment of CoA.

Developmental Changes in Myocardial Contractile Reserve in the Lamb

ABSTRACT: We have assessed serial changes in myocardial contractility and reserve in the normal lamb over the first month of life using an in vivo adaptation of the endsystolic pressure-volume relationship. Via a left thoracotomy, we insert a catheter tip pressure transducer into the left ventricle, affix an echo transducer onto the left ventricular epicardium, place an electromagnetic flow transducer around the pulmonary artery, and insert catheters for monitoring and infusions. We measure contractility by generating left ventricular wall stress-volume index (the cube of dimension) curves, at the same time increasing afterload by infusing phenylephrine. The slope of the endsystolic wall stress-volume index relationship is our index of contractility. Weekly studies were performed at rest and during isoproterenol infusion in 12 animals, and after propranolol administration in four. The data showed a progressive decrease in resting contractility but no change in maximal contractility during isoproterenol infusion over the 4 wk. Taking each week separately, the average increase in contractility during isoproterenol infusion was small at 1 wk (13%), moderate at 2 and 3 wk (24 and 26%, respectively), and large at 4 wk (79%). β-Adrenergic blockade with propranolol caused a significant decrease in contractility in three of four animals studied at 1 wk, in only one of four animals at 2 wk, and in none of four animals at 3 or 4 wk. Thus, the newborn lamb shows a limited reserve in contractility that increases progressively with age; the limited reserve appears secondary to a high resting β-adrenergic state.

Aortoventriculoplasty with the pulmonary autograft: The "Ross-Konno" procedure

BACKGROUND For patients with complex left ventricular outflow tract obstruction, including hypoplastic aortic anulus with or without severe diffuse subaortic stenosis, various aortoventriculoplasty procedures (e.g., Konno procedure and its modifications; extended aortic allograft root replacement) are important management options. In younger patients, however, reoperation for valve replacement is inevitably required, and anticoagulation issues pose additional problems. The pulmonary autograft provides a promising option for aortic valve replacement as part of the aortoventriculoplasty procedure in children. Long-term follow up shows that the pulmonary autograft functions well as the systemic arterial (neoaortic) valve and that valve growth occurs. METHODS Between July 1993 and May 1995, 11 patients 4 days to 17 years old (median 12 months) underwent aortoventriculoplasty with pulmonary autograft (Ross-Konno procedure). The diagnoses were aortic stenosis with or without subaortic stenosis (n = 8), Shone complex (n = 2), and interrupted aortic arch with subaortic stenosis (n = 1). On average, 1.9 previous interventions had been performed per patient, including a previous Konno procedure in one patient. The aortic root was replaced with a pulmonary autograft valve. The left ventricular outflow tract was enlarged with a Dacron polyester fabric patch in two patients, with an allograft aortic patch in two patients and a right ventricular infundibular free wall muscular extension harvested in continuity with the autograft in seven patients. RESULTS Intraoperative transesophageal echocardiographic assessment revealed mild aortic insufficiency in one patient. One patient had a residual left ventricular outflow tract gradient of 15 mm Hg. Significant complications were cardiac tamponade from bleeding (n = 1) and complete heart block necessitating a permanent pacemaker (n = 1). Follow-up ranged from 2 weeks to 16 months. To date, there have been no late deaths or reoperations. Follow-up echocardiography revealed mild autograft insufficiency in one patient and a 16 mm Hg residual left ventricular outflow tract gradient in one patient. CONCLUSIONS Initial experience suggests that aortoventriculoplasty with the pulmonary autograft is an excellent alternative for young patients with complex left ventricular outflow tract obstruction. Because the pulmonary autograft has been shown to grow after implantation, reoperation on the left ventricular outflow tract is likely to be avoided.

Complications of pediatric cardiac catheterization: A 3-year study

To determine the current risk of pediatric cardiac catheterization, the complications and incidents of all catheterizations performed in a pediatric laboratory between January 1986 and October 1988 were prospectively recorded and compared with results from a 1974 study from the same institution. In the current study 1,037 catheterizations, 885 diagnostic and 152 diagnostic/interventional procedures, were performed in 888 patients (aged 1 day to 27 years, median 15.6 months). There were 15 major complications (1.4%), 70 minor complications (6.8%) and 30 incidents (2.9%). Two patients died as a result of the procedure and two as a result of pericatheterization clinical deterioration caused by the cardiac abnormality. The great majority of complications were successfully treated or were self-limited and the patients had no residua. Of patients with 13 nonfatal major complications and 70 minor complications, residua were evident in 7 patients and 3 without evident residua had the potential for sequelae (0.7% and 0.3% of catheterizations). A comparison of the diagnostic and balloon atrial septostomy cases in the present study with similar cases in the 1974 study shows that the incidence of major complications has decreased from 2.9% to 0.9% (p less than 0.0001); minor complications and incidents have decreased from 11.7% to 7.9% (p less than 0.006) and pericatheterization deaths not attributable to catheterization have decreased from 2.8% to 0.2% (p less than 0.0001). Changes in pericatheterization medical management, patient selection for catheterization and catheterization techniques probably account for these improvements.

Relationship between Brain Blood Flow and Carotid Arterial Flow in the Sheep Fetus

ABSTRACT: The present study investigates whether changes in total brain blood flow can be reliably estimated by changes in carotid arterial blood flow in fetal and perinatal lambs. We therefore compared carotid arterial blood flow, measured with implanted transit-time ultrasound transducers, with brain blood flow, measured by radioactive microspheres in fetal lambs during normal oxygenation and during pulmonary ventilation with oxygen, with Po: ranging from levels normal for the healthy fetus to levels normally seen postnatally. Cerebral perfusion pressure was modified over a wide range to alter brain blood flow: it was decreased by balloon occlusion of the brachiocephalic trunk and increased by a balloon occluder around the aortic isthmus. Carotid arterial blood flow and brain blood flow were closely related (r = 0.97, p < 0.0001). The relationship was not altered at different levels of oxygenation. However, measurements during higher cerebral perfusion pressures, obtained during aortic isthmus occlusion, had a negative influence on the agreement between carotid arterial blood flow and brain blood flow. When excluding values obtained by aortic isthmus occlusion, changes of 20% or more in brain blood flow could be predicted with carotid arterial blood flow within a confidence limit of 95%. Blood flow measurements in the carotid artery may be useful to estimate changes in brain perfusion.

Effects of Birth-Related Events on Central Blood Flow Patterns

ABSTRACT. We determined the effects of three components of the birth process on central blood flow patterns in fetal sheep. We instrumented 16 fetal sheep at 133.0 ± 1.2 days gestation, inserting various intravascular catheters, intubating the trachea, and placing an inflatable balloon around the umbilical cord. After 2-3 days, we determined central blood flow patterns using radionuclidelabeled microspheres under control conditions, during positive pressure ventilation without oxygenation, during ventilation with 100% O2, and after umbilical cord occlusion. The foramen ovale right to left shunt was essentially abolished, decreasing from 102 ± 48 to 66 ± 40 ml/min/kg with ventilation, and to only 13 ± 10 ml/min/kg with oxygenation. The ductus arteriosus right to left shunt decreased progressively, from a control level of 224 ± 64 to 6 ± 10 ml/min/kg after umbilical cord occlusion. A ductus arteriosus left to right shunt appeared with oxygenation (41 ± 2 6 ml/min/kg) and increased to 65 ± 43 ml/min/kg after cord occlusion. Left ventricular output increased progressively as a percentage of combined ventricular output (from a control value of 34.8 to 59.5% after cord occlusion), and increased absolutely with ventilation (from 134 ± 44 to 211 ± 8 7 ml/min/kg). However, right ventricular output decreased (from a control value of 258 ± 75 to 144 ± 36 ml/min/kg after cord occlusion) so that combined ventricular output did not change. Although the transition from the fetal to neonatal circulatory pattern was accomplished by simulating these three components of the birth process, none is alone responsible for the large increase in combined ventricular output normally seen at birth.