Ralph D. Siewers

Anomalous Origin of the Left Coronary Artery from the Pulmonary Artery A New Method of Surgical Repair

Anomalous origin of the left coronary artery from the pulmonary artery has been surgically corrected by means of a technique that avoids direct suturing of the coronary artery itself. The anomalous left coronary artery is removed from the pulmonary artery with a cuff of pulmonary artery tissue about its orifice. In a five-and-one-half-year-old patient the anomalous coronary artery was anastomosed directly to the aorta using this technique. In another patient, seven months of age, the anomalous coronary artery could not be anastomosed directly to the aorta and a segment of the patients subclavian artery was interposed between the left coronary artery and the aorta to complete the anastomosis. In the latter patient, profound hypothermia and circulatory arrest were used during construction of the anastomosis in an attempt to minimize further myocardial damage. The establishment of a two coronary artery system has been demonstrated to be feasible in the infant or young child with this anomaly.

Absent right superior vena cava with persistent left superior vena cava: implications and management.

Seven cases of absent right superior vena cava with persistent left superior vena cava and normal situs were diagnosed at Childrens Hospital of Pittsburgh. All patients had associated cardiac defects. In two cases the diagnosis was made at autopsy, the first in 1957 and in a 26 day old infant with multiple cogenital defects and the second in 1965 in a 22 day old infant who had pulmonary atresia with ventricular septal defect and patent ductus arteriosus. Since 1966 absent right superior vena cava has been diagnosed at cardiac catheterization in five children. Three of these children have had surgery, two for subaortic stenosis and one for an atrial septal defect. One has an insignificant atrial septal defect and the fifth has a ventricular septal defect. The electrocardiogram of four reveals s short P-R interval and a leftward frontal plane axis of the P wave, suggesting a low atrial focus. None has had any significant conduction problem. All five children are living and well, the oldest has survived 13 years postoperatively. Certain precautions are necessary should corrective cardiac surgery or transvenous pacemaker insertion be necessary.

Coarctation of the Aorta in Infants and Children: 25 Years of Experience

Repair of coarctation of the aorta was performed in 334 patients ranging from less than a year to 16 years of age at Childrens Hospital of Pittsburgh from 1953 to 1977. Resection and end-to-end anastomosis were performed in 310, interposition grafts in 7, and other procedures in 17. There were 41 operative deaths among the 95 infants less than 1 year old (43% mortality); all of these infants had associated cardiac anomalies. Only 1 operative death occurred in patients older than a year (0.4% mortality). No hospital deaths occurred in patients with isolated coarctation of the aorta. Eleven late deaths were due to associated anomalies (7) and unrelated or unknown causes (4). Postoperatively, hemorrhage occurred in 7, paradoxical or persistent hypertension in 128, postcoarctectomy syndrome in 32, neurological problems in 14, pulmonary complications in 53, and infections in 12 patients. Restenosis occurred in 26 patients (8%); only 10 have required reoperation. Residual hypertension was present in 28 of 264 patients (11%). Mortality from coarctation resection remains high in infants, but is minimal in children older than 1 year. Based on minimizing the risk of restenosis and residual hypertension, elective repair of coarctation is recommended when the patient is about 6 years of age.

Regional low-flow perfusion provides somatic circulatory support during neonatal aortic arch surgery

BACKGROUND Regional low-flow perfusion has been shown to provide cerebral circulatory support during neonatal aortic arch operations. However, its ability to provide somatic circulatory support remains unknown. METHODS Fifteen neonates undergoing arch reconstruction with regional perfusion were studied. Three techniques were used to assess somatic perfusion: abdominal aortic blood pressure, quadriceps blood flow (near-infrared spectroscopy), and gastric tonometry. RESULTS Twelve patients required operation for hypoplastic left heart syndrome, and 3 required arch reconstruction with a biventricular repair. There was one death (7%). Abdominal aortic blood pressure was higher (12+/-3 mm Hg versus 0+/-0 mm Hg), and quadriceps blood volumes (5+/-24 versus -17+/-26) and oxygen saturations (57+/-25 versus 33+/-12) were greater during regional perfusion than during deep hypothermic circulatory arrest (p < 0.05). During rewarming, the arterial-gastric mucosal carbon dioxide tension difference was lower after circulatory arrest than after regional perfusion (-3.3+/-0.3 mm Hg versus 7.8+/-7.6 mm Hg, p < 0.05). CONCLUSIONS Regional low-flow perfusion provides somatic circulatory support during neonatal arch surgical procedures. Support of the subdiaphragmatic viscera should improve the ability of neonates to survive the postoperative period.

Extracorporeal membrane oxygenation for postcardiotomy cardiogenic shock in children

Size limitations and technical barriers prohibit the use of many conventional mechanical circulatory support systems for postcardiotomy ventricular dysfunction in pediatric populations. Extracorporeal membrane oxygenation (ECMO), frequently used to treat neonatal respiratory failure, can provide cardiac support and is effective treatment of postoperative myocardial failure in children. From 1981 to 1987, 10 patients aged 2 days to 5 years were maintained on ECMO for 15 to 144 hours (mean duration, 92 +/- 16 hours) after cardiotomy. Operative procedures included repair of tetralogy of Fallot (2 patients), closure of a ventricular septal defect (2), the Senning procedure for transposition of the great arteries (1 patient), repair of interrupted aortic arch with closure of a ventricular septal defect (1), repair of a partial atrioventricular septal defect (2), closure of a ventricular septal defect with excision of an anomalous muscle bundle (1), and the Fontan procedure (1). Venoarterial ECMO was established in all 10 children. Six patients underwent transthoracic right atrium-ascending aorta cannulation, 3 had right internal jugular vein-right common carotid artery cannulation through a cervical incision, and 1 had right internal jugular vein-left axillary artery cannulation. Eight of the 10 patients were successfully weaned from ECMO, and 7 are long-term survivors. There were 3 deaths; 1 was caused by cardiac and acute renal failure complicated by sepsis two days after decannulation, another occurred 19 days after atrioventricular septal defect repair, and 1 was caused by massive pulmonary hemorrhage. Major hemorrhage developed in 3 patients while on ECMO; 2 required premature decannulation for mediastinal bleeding from operative sites and ultimately survived, and 1 died of respiratory failure as a result of endobronchial bleeding. We conclude that the use of ECMO in pediatric populations for transient postoperative ventricular dysfunction improves survival with limited overall morbidity.

Coarctation and hypoplasia of the aortic arch: Will the arch grow?

Hypoplasia of the transverse aortic arch of various degrees of severity is commonly seen in infants who have coarctation of the aorta. It is more often present when the coarctation is associated with intracardiac lesions that diminish or limit forward flow in the ascending aorta and promote right to left flow through an arterial duct. The increased frequency of surgical treatment of infants with complex coarctation, which is in part related to the ability to stabilize their condition with prostaglandin E1, has posed the question of the potential for growth and development of the originally hypoplastic aortic arch after conventional repair of aortic coarctation. Review of our experience with transverse aortic arch hypoplasia, found in 33 (32%) of 102 infants undergoing coarctation repair by subclavian flap aortoplasty or classic resection and end-to-end anastomosis, revealed excellent growth of the transverse arch after repair in all patients available for linear follow-up. The currently proposed extended arch repair should be reserved for the small group of infants with transverse aortic arch to ascending aorta diameter ratios (arch indices) of less than 0.25.

Tetralogy of Fallot with absent pulmonic valve: analysis of 17 patients.

Seventeen patients with tetralogy of Fallot (TF) and absent pulmonic valve were seen at Childrens Hospital of Pittsburgh from 1958 to 1981. In 7 patients, severe respiratory symptoms developed due to bronchial compression by an aneurysmal pulmonary artery, and 6 died. In 4 patients, moderate respiratory symptoms developed. Six patients remained free of respiratory distress. Medical and surgical management of patients with respiratory distress in infancy has been frustrating and frequently unsuccessful. A 4-month-old infant with respiratory distress underwent complete intracardiac repair with valve insertion and has subsequently survived with relief of symptoms. Considering the high mortality rate in this group of patients, further attempts at aggressive surgical repair in infancy for patients with severe respiratory symptoms is warranted. An anatomic review of pathologic specimens with this anomaly confirmed previous reports of the frequent association of absence of the ductus arteriosus in patients with tetralogy of Fallot and absent pulmonary valve. The exception is noted in patients with discontinuity between the right and left pulmonary arteries in which a ductus arteriosus may be present supplying the isolated left pulmonary artery.

The effects of cardiopulmonary bypass on remifentanil kinetics in children undergoing atrial septal defect repair

UNLABELLED Cardiopulmonary bypass (CPB) can greatly influence the pharmacokinetics of opioids. This study investigated the pharmacokinetic profile of remifentanil in 12 pediatric patients undergoing CPB for repair of an atrial septal defect. All patients received remifentanil (5 microg/kg) over 1 min into a peripheral vein both before the onset of CPB and after the discontinuation of CPB. Arterial blood samples were obtained at defined time periods, and remifentanil concentration was determined using high-performance liquid chromatography ultraviolet detection. The pharmacokinetic profiles both before and after bypass were determined in all 12 patients. There was no change in the volume of distribution at steady state, the volume of the central compartment, or the alpha- and beta-elimination half-life. Although the clearance values increased 20% in the postbypass period (from 38.7 +/- 9.6 to 46.8 +/- 14 mL x kg(-1) x min(-1), there was no meaningful change in the coefficient of variation (from 25% to 30%). IMPLICATIONS After cardiopulmonary bypass the clearance of remifentanil increases in children. However, the relative lack of change in the coefficient of variation suggests that remifentanil should be a predictable drug in the postcardiopulmonary bypass period.

Anomalous origin of one pulmonary artery from the ascending aorta: a review of echocardiographic, catheter, and morphological features.

Six patients with anomalous origin of one pulmonary artery from the ascending aorta were reviewed. Four had anomalous origin of the right pulmonary artery and two had anomalous origin of the left pulmonary artery from the ascending aorta. Two of these six patients had tetralogy of Fallot. Two patients died in the first month of life. No changes in the pulmonary vasculature were seen at necropsy. Corrective surgery was attempted in two patients with associated tetralogy of Fallot when they were two years old but both died. At necropsy there was severe pulmonary vascular disease in the lung supplied by the anomalous pulmonary artery but no pulmonary vascular hypertensive changes in the lung supplied by the pulmonary artery from the right ventricle. Two recent patients underwent successful anastomosis of the anomalous pulmonary artery to the main pulmonary artery at three months and one month and three weeks of age respectively. Intraoperative lung biopsy in the latter patient showed early changes in both lungs. Both echocardiography and cardiac catheterisation were used in the diagnoses. Systemic or suprasystemic pressures were found in the pulmonary artery arising from the right ventricle as well as the anomalous pulmonary artery in the three patients without tetralogy of Fallot. Anomalous origin of a pulmonary artery from the ascending aorta is a distinct entity and differs from other aorto-pulmonary arterial connections. Early surgical intervention is recommended in all patients (including those patients with associated tetralogy of Fallot) because of the risk of rapid development of irreversible pulmonary vascular disease.

Amrinone in neonates and infants after cardiac surgery

Eighteen critically ill postoperative patients less than 1 yr of age were studied to determine the pharmacokinetics and adverse effects of amrinone. All patients had undergone cardiopulmonary bypass for repair of congenital heart lesions. Plasma samples were obtained every 12 h while patients were receiving amrinone to determine when steady state was achieved; samples were also obtained within 24 h after amrinone had been discontinued. Elimination half-life (T1/2), clearance, and volume of distribution were calculated from plasma amrinone concentrations, and the incidence of platelet transfusion was monitored. T1/2(22.2 vs. 6.8 h) and clearance (1.1 vs. 2.6 ml/min.kg), but not the volume of distribution (1.8 vs. 1.6 L/kg), differed significantly in patients less than 4 wk of age in comparison to patients greater than 4 wk of age. A negative correlation between T1/2 and age (r = -.79) was observed. Platelets were administered no more frequently in study patients than in a similar group that did not receive amrinone. To achieve the plasma concentration of amrinone that is therapeutic in adults, current dosage recommendations are inadequate in neonates and infants. Infants should receive an initial iv amrinone bolus of 3.0 to 4.5 mg/kg in divided doses followed by a continuous infusion of 10 micrograms/kg.min, while neonates should receive a similar bolus followed by a continuous infusion of 3 to 5 micrograms/kg.min.