Mycobacterium avium binds to mouse intestinal mucus aldolase

SETTING

Mycobacterium avium complex (MAC) is known to colonize the gastrointestinal tract of human immunodeficiency virus (HIV) infected patients before causing bacteremia and disseminated disease. However, the mechanism involved in the gastrointestinal colonization is not known.

OBJECTIVE

To identify putative intestinal mucus receptors which serve as anchor for MAC colonization.

DESIGN

C57BL/6 mouse intestinal mucus was subjected to single and two-dimensional electrophoresis and blotted on nitrocellulose membranes. MAC specific mucus proteins were identified by probing the mucus western blots with biotinylated proteins derived from M.avium strain 101 (MAC101).

RESULTS

Biotinylated MAC 101 proteins recognized a 39 kDa intestinal mucus glycoprotein. The protein displaying an isoelectric point (pI) of 9.0, was found to be periodate sensitive but resistant to sialidase, heparinase I and chondroitinase ABC. The internal amino acid sequence of the 39 kDa protein displayed homology with fructose-1-6-bisphosphate aldolase B (aldolase). The proclivity between MAC adhesins and aldolase was confirmed by probing rabbit muscle aldolase with MAC proteins. Furthermore, both 25 and 31 kDa MAC adhesins, superoxide dismutase and heparin binding protein, respectively, were found to bind to aldolase.

CONCLUSIONS

MAC binds to intestinal mucus aldolase, conceivably facilitating intestinal colonization of the organism.

Interaction of Mycobacterium tuberculosis with human respiratory epithelial cells (HEp-2)

SETTING

Mycobacterium tuberculosis (MTB) is known to adhere to, invade, multiply inside, and modulate respiratory epithelial cell functions. However, the mode and the molecules involved in the interaction of MTB with respiratory cells are not known.

OBJECTIVE

To study post-adherence morphological changes in human respiratory epithelial cells and identify MTB components involved in the binding to these cells.

DESIGN

The mechanism of interaction of MTB human respiratory epithelial cells (HEp-2) was investigated by incubating MTB with HEp-2 cells, whereupon the morphological changes were examined under scanning electron microscopy. MTB components involved in the interaction with HEp-2 cells were identified by probing Western blots of mycobacterial sonicates with biotinylated HEp-2 extracts.

RESULTS

MTB readily bound to the surface of HEp-2 cells. Adherence of tubercle bacilli on the surface caused membrane perturbation resulting in increased surface membrane projections, particularly towards the margins of the cells. Long thin epithelial membrane projections formed loops around the bacilli holding them on the surface. Membrane projections fused to form a web in which the bacilli were entrapped. Concomitant membrane cavitations seen beneath the site of attachment of the bacilli conceivably caused internalization of the organisms. At least five MTB proteins ( approximately 112, 35, 28, 21 and 15 kDa) specific for HEp-2 cells were identified. Of these, the 28 kDa protein was the predominant HEp-2-binding protein and was found to be heparin-binding hemagglutinin (HBHA). While M. bovis BCG strain showed the same five HEp-2-binding proteins, M. smegmatis, displayed only one (31 kDa) HEp-2-specific protein.

CONCLUSION

MTB binds to HEp-2 cells through multiple proteins, and the binding causes membrane perturbations that result in internalization of the organisms.

Cardiac surgery for premature and low birth weight neonates

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 this approach has been shown to be high. At the University of California San Francisco, our approach to these infants has been one of complete repair in the neonatal period or as early as possible. Since 1992, 116 neonates and infants under 2,500 g underwent complete repair of simple and complex cardiac defects using cardiopulmonary bypass and circulatory arrest was avoided in the majority. Actuarial survival was 80% at 1 year. Noncardiac abnormalities contribute significantly to perioperative and late morbidity and mortality. Reintervention rates are comparable to other neonates. Our data suggests that complete repair of simple and complex congenital heart defects can be performed safely and effectively in premature and low birth weight infants.

Techniques to avoid circulatory arrest in neonates undergoing repair of complex heart defects

Advances in cardiopulmonary bypass and cardiac surgical techniques have tremendously improved the outlook for children born with congenital heart defects. However, cardiopulmonary bypass, hypothermia, and circulatory arrest are all unphysiologic states and are associated with some morbidity, and the most significant are neurologic sequelae, which can be subtle or devastating. Circulatory arrest, often used as an adjunct to deep hypothermia, is a major contributing factor to the neurologic complications after cardiopulmonary bypass. In the last decade, techniques to avoid circulatory arrest have been introduced with a substantial decrease in neurologic sequelae.

Hemidiaphragmatic paralysis increases postoperative morbidity after a modified Fontan operation

OBJECTIVES

After a Fontan procedure, forward pulmonary blood flow is augmented during inspiration because of negative intrathoracic pressure. Total pulmonary blood flow is higher during inspiration. With hemidiaphragmatic paralysis, inspiratory augmentation of pulmonary flow is lost or diminished. The objective of this study was to compare early postoperative morbidity after the modified Fontan operation in patients with and without hemidiaphragmatic paralysis.

METHODS

A case-control analysis was performed comparing 10 patients with documented hemidiaphragmatic paralysis against 30 patients without paralysis who were matched for diagnosis, fenestration, and age. The following early postoperative outcomes were assessed: duration of ventilator support, duration of hospital stay, incidence of ascites, prolonged effusions, and readmission.

RESULTS

Preoperatively, there were no significant differences between the 2 groups. However, among the postoperative outcomes, the duration of hospital stay (25.4 +/- 16.6 days vs 10.8 +/- 6.3 days; P =.03), incidence of ascites (70% vs 3%; P <.001), prolonged pleural effusions (60% vs 13%; P =.007), and readmission (50% vs 7%; P =.007) were significantly greater in patients with hemidiaphragmatic paralysis than in those without hemidiaphragmatic paralysis.

CONCLUSIONS

Hemidiaphragmatic paralysis after the modified Fontan operation is associated with an increase in early morbidity. Care should be taken to avoid injury to the phrenic nerve. Patients with prolonged effusions should be evaluated for hemidiaphragmatic paralysis.

Superior cavopulmonary anastomosis suppresses the activity and expression of pulmonary angiotensin-converting enzyme

BACKGROUND

Superior cavopulmonary anastomosis is widely used for palliation of various forms of univentricular heart defects. However, clinically significant pulmonary arteriovenous malformations develop in 15% to 25% of patients after surgery.

OBJECTIVE

To assess altered regulation of pulmonary vascular tone caused by superior cavopulmonary anastomosis in an ovine model.

METHODS

Lambs, aged 35 to 45 days, underwent an end-to-end anastomosis of the superior vena cava to the right pulmonary artery. In age-matched controls, a sham operation was performed. Arteriovenous malformations were detectable by contrast echocardiography by 8 weeks after surgery. Animals (n = 24) were studied at various time points after the operations. Expression of angiotensin-converting enzyme messenger RNA, protein levels, and enzyme activity were measured in lung homogenates. Levels of angiotensin II were measured by enzyme-linked immunosorbent assay.

RESULTS

Expression of angiotensin-converting enzyme messenger RNA and protein was significantly reduced at 1 to 5 weeks after superior cavopulmonary anastomosis. Angiotensin-converting enzyme activity in the right lung of animals subjected to superior cavopulmonary anastomosis was reduced 86% +/- 1% (standard deviation) compared with control values at 1 week (P =.003) and 77% +/- 8.5% at 2 weeks (P <.001) after surgery. This correlated with a 59% +/- 3.5% (P =.007) reduction in angiotensin II levels up to 5 weeks after cavopulmonary anastomosis. By 15 weeks after the operations, angiotensin II levels were equivalent to control levels (P =.19).

CONCLUSIONS

Superior cavopulmonary anastomosis causes an early reversible reduction in activity and expression of angiotensin-converting enzyme, resulting in decreased circulating levels of the vasoconstrictor angiotensin II. These results suggest that the ability of the pulmonary endothelium to regulate vascular tone is inhibited after superior cavopulmonary anastomosis. Dilation of the affected vasculature induced by cavopulmonary anastomosis may contribute to the disordered vascular remodeling observed in this setting.

A prospective randomized study comparing volume-standardized modified and conventional ultrafiltration in pediatric cardiac surgery

BACKGROUND

Modified ultrafiltration has been touted as superior to conventional ultrafiltration for attenuating the consequences of hemodilution after cardiac surgery with cardiopulmonary bypass in children. We conducted a prospective randomized study to test the hypothesis that modified and conventional ultrafiltration have similar clinical effects when a standardized volume of fluid is removed.

METHODS

From October 1998 to September 1999, 110 children weighing 15 kg or less (median weight 6.1 kg, median age 6.3 months) undergoing surgery with cardiopulmonary bypass for functionally biventricular congenital heart disease were randomized to conventional (n = 67) or arteriovenous modified ultrafiltration (n = 43) for hemoconcentration. The volume of fluid removed with both methods was standardized as a percentage of effective fluid balance (the sum of prime volume and volume added during cardiopulmonary bypass minus urine output): in patients weighing less than 10 kg, 50% of effective fluid balance was removed, whereas 60% was removed in patients weighing 10 to 15 kg. Hematocrit, hemodynamics, ventricular function, transfusion of blood products, and postoperative resource use were compared between groups.

RESULTS

There were no significant differences between groups in age, weight, or duration of cardiopulmonary bypass. The total volume of fluid added in the prime and during bypass was greater in patients undergoing conventional ultrafiltration than in those receiving modified ultrafiltration (205 +/- 123 vs 162 +/- 74 mL/kg; P =.05), although the difference was due primarily to a greater indexed priming volume in patients having conventional ultrafiltration. There was no difference in the percentage of effective fluid balance that was removed in the 2 groups. Accordingly, the volume of ultrafiltrate was greater in patients receiving conventional than modified ultrafiltration (95 +/- 63 vs 68 +/- 28 mL/kg; P =.01). Preoperative and postoperative hematocrit levels were 35.6% +/- 6.6% and 36.3% +/- 5.6% in patients having conventional ultrafiltration and 34.4% +/- 6.7% and 38.7% +/- 7.5% in those having modified ultrafiltration. By repeated-measures analysis of variance, patients receiving modified and conventional ultrafiltration did not differ with respect to hematocrit value (P =.87), mean arterial pressure (P =.85), heart rate (P =.43), or left ventricular shortening fraction (P =.21) from baseline to the postbypass measurements. There were no differences between groups in duration of mechanical ventilation, stay in the intensive care unit, or hospitalization.

CONCLUSIONS

When a standardized volume of fluid is removed, hematocrit, hemodynamics, ventricular function, requirement for blood products, and postoperative resource use do not differ between pediatric patients receiving conventional and modified ultrafiltration for hemoconcentration after cardiac surgery.

The Ross procedure in children and young adults: a word of caution

BACKGROUND

Disease of the aortic valve in children and young adults is a complex entity whose management is the subject of controversy. The Ross and the Ross-Konno procedures have become the primary choices for aortic valve replacement in children because of growth potential, optimal hemodynamic performance, and lack of the need for anticoagulation. However, concern persists regarding the longevity of the pulmonary autograft, especially in patients with aortic insufficiency.

METHODS

Between June 1993 and February 2000, 72 Ross and Ross-Konno procedures were performed at our institution: 81% of the patients were less than 15 years old. Preoperative, postoperative, and follow-up clinical, echocardiographic, and hemodynamic data were reviewed. Statistical analysis was performed to identify the risk factors for deteriorating autograft function.

RESULTS

Aortic insufficiency was an indication for the Ross procedure in 17 patients and mixed lesions with predominant aortic insufficiency in 10. Of the 45 other patients, 32 had aortic stenosis and 13 had mixed lesions with predominant aortic stenosis. There were no deaths during a follow-up of 5 to 80 months. Autograft reoperation was necessary in the follow-up period in 7 patients for severe aortic insufficiency. Moderate insufficiency was identified in 5 additional patients. Aortic insufficiency or predominant aortic insufficiency, as a preoperative hemodynamic indication for the Ross procedure, reached statistical significance (P =.031) as a risk factor for autograft failure.

CONCLUSION

The Ross and the Ross-Konno procedures have changed the prognosis of children and young adults with complex aortic valve disease. However, the Ross procedure should be performed with caution in older children in whom aortic insufficiency is a preoperative hemodynamic indication. Further follow-up to delineate the risk factors for autograft dysfunction in children and young adults is necessary to better define the indications for the Ross procedure.

The safety and efficacy of sevoflurane anesthesia in infants and children with congenital heart disease

We tested the hypothesis that sevoflurane is a safer and more effective anesthetic than halothane during the induction and maintenance of anesthesia for infants and children with congenital heart disease undergoing cardiac surgery. With a background of fentanyl (5 microg/kg bolus, then 5 microg. kg(-1). h(-1)), the two inhaled anesthetics were directly compared in a randomized, double-blinded, open-label study involving 180 infants and children. Primary outcome variables included severe hypotension, bradycardia, and oxygen desaturation, defined as a 30% decrease in the resting mean arterial blood pressure or heart rate, or a 20% decrease in the resting arterial oxygen saturation, for at least 30 s. There were no differences in the incidence of these variables; however, patients receiving halothane experienced twice as many episodes of severe hypotension as those who received sevoflurane (P = 0.03). These recurrences of hypotension occurred despite an increased incidence of vasopressor use in the halothane-treated patients than in the sevoflurane-treated patients. Multivariate stepwise logistic regression demonstrated that patients less than 1 yr old were at increased risk for hypotension compared with older children (P = 0.0004), and patients with preoperative cyanosis were at increased risk for developing severe desaturation (P = 0.049). Sevoflurane may have hemodynamic advantages over halothane in infants and children with congenital heart disease.

IMPLICATIONS

In infants and children with congenital heart disease, anesthesia with sevoflurane may result in fewer episodes of severe hypotension and less emergent drug use than anesthesia with halothane.

Improved surgical outcome after fetal diagnosis of hypoplastic left heart syndrome

BACKGROUND

Hypoplastic left heart syndrome (HLHS) is frequently diagnosed prenatally, but this has not been shown to improve surgical outcome.

METHODS AND RESULTS

We reviewed patients with HLHS between July 1992 and March 1999 to determine the influence of prenatal diagnosis on preoperative clinical status, outcomes of stage 1 surgery, and parental decisions regarding care. Of 88 patients, 33 were diagnosed prenatally and 55 after birth. Of 33 prenatally diagnosed patients, 22 were live-born, and pregnancy was terminated in 11. Of 22 prenatally diagnosed patients who were live-born, 14 underwent surgery, and parents elected to forego treatment in 8. Of 55 patients diagnosed postnatally, 38 underwent surgery, and 17 did not because of parental decisions or clinical considerations. Prenatally diagnosed patients were less likely to undergo surgery than patients diagnosed after birth (P:=0.008). Among live-born infants, there was a similar rate of nonintervention. Among patients who underwent surgery, survival was 75% (39/52). All patients who had a prenatal diagnosis and underwent surgery survived, whereas only 25 of 38 postnatally diagnosed patients survived (P:=0.009). Patients diagnosed prenatally had a lower incidence of preoperative acidosis (P:=0.02), tricuspid regurgitation (P:=0.001), and ventricular dysfunction (P:=0.004). They were also less likely to need preoperative inotropic medications or bicarbonate (P:=0.005). Preoperative factors correlating with early mortality included postnatal diagnosis (P:=0.009), more severe acidosis (P:=0.03), need for bicarbonate or inotropes (P:=0.008 and 0.04), and ventricular dysfunction (P:=0.05).

CONCLUSIONS

Prenatal diagnosis of HLHS was associated with improved preoperative clinical status and with improved survival after first-stage palliation in comparison with patients diagnosed after birth.

Perioperative administration of angiotensin converting enzyme inhibitors decreases the severity and duration of pleural effusions following bidirectional cavopulmonary anastomosis

BACKGROUND

Pleural effusions after bidirectional cavopulmonary anastomosis remain a significant cause of morbidity. Prolonged effusions in such patients have been associated with persistent elevations in plasma renin and angiotensin II.

METHODS

We conducted a controlled study in 36 patients (median age 8 months) undergoing bidirectional cavopulmonary anastomosis. Enalapril (5 mcg/kg) was administered intravenously within 1 hour of surgery and every 12 hours thereafter in 18 patients; when these patients were tolerating feeds, enalapril was switched to enteral captopril (3 mg/kg/day) every 8 hours. The other 18 patients did not receive perioperative angiotensin converting enzyme inhibitors. Using standardized criteria for discontinuation of chest tubes (< 2 mL/kg/day), volume and duration of pleural drainage were compared between groups. RESULTS. There were no differences between groups in demographic, diagnostic, or hemodynamic factors. There was no difference in cardiopulmonary bypass time between groups and no difference in postoperative pulmonary arterial pressures. The duration of pleural drainage was shorter (2.2+/-1.4 vs 5.9+/-1.4 days, p<0.001) and the volume less during the first 24 hours (4.7+/-1.2 vs 7.7+/-2.1 mL/kg, p<0.001) and overall (10.6+/-2.4 vs 19.6+/-4.5 mL/kg, p<0.001) in patients who received angiotensin converting enzyme inhibitors than those who did not. Readmission for persistent effusions was required in 3 patients who did not receive angiotensin converting enzyme inhibitors and none who did (p=0.11).

CONCLUSIONS

Perioperative administration of angiotensin converting enzyme inhibitors is associated with decreased severity and duration of pleural effusions following bidirectional cavopulmonary anastomosis.

A new flavone glycoside, 5-hydroxy 7,3',4',5'-tetra-methoxyflavone 5-O-beta-D-xylopyranosyl-(1-->2)-alpha-L-rhamnopyranoside from Bauhinia variegata Linn

A new flavone glycoside m.f. C(30)H(36)O(15) m.p. 252-253 degrees C, [M]+ 636 (EIMS) was isolated from the acetone soluble fraction of the concentrated 95% ethanolic extract of the seeds of Bauhinia variegata (Linn). It was identified as 5-hydroxy7,3',4',5'-tetra-methoxyflavone 5-O-beta-D-xylopyranosyl-(1-->2)-alpha-L-rhamnopyranoside (1) by various colour reactions, chemical degradations and spectral techniques.

A census of long-stay patients in government mental hospitals in India

A single day census found that long-stay patients (LSP) numbering 7,307 accounted for about 48% of the total inpatient strength of 15,345 in government mental hospitals in India. A load of 2695 (37%) LSP were in two to five years duration of stay, 2782 (38%) were in five to fifteen years duration of stay, and the remaining 1830 (25%) were staying for more than fifteen years. About 11% of LSP were aged sixty years and above, majority (53%) were males, non-voluntary cases constituted 80%. and more than two-thirds (69%) were schizophrenics. The characteristics distributions associated with high rates of LSP at individual hospitals were identified. The load of LSP was decreased by 9% during the period from 1993 to 1999.

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 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.

Infradiaphragmatic totally anomalous pulmonary venous return with two separate descending veins in association with right atrial isomerism

We present the case of a 1-month-old infant with right atrial isomerism and complex functionally univentricular heart disease, in whom totally anomalous pulmonary venous return drained below the diaphragm via two separate vertical veins. One of the descending vertical veins drained the entire right lung and the left upper lobe, while the other drained the remainder of the left lung. Only one similar case has been described previously.

Neutrophil degranulation and complement activation during fetal cardiac bypass

BACKGROUND

Fetal cardiac bypass results in dysfunction of the fetoplacental unit (FPU) characterized by increased placental vascular resistance and respiratory acidosis. However the mechanisms of this dysfunction are not completely understood. To test the hypothesis that complement activation and neutrophil degranulation may contribute to the placental dysfunction associated with fetal bypass, we compared placental hemodynamics, complement activation, and neutrophil degranulation among fetuses exposed to cardiac bypass with a miniaturized bypass circuit including an in-line axial flow pump (Hemopump), fetuses undergoing bypass with a conventional roller pump circuit, and control fetuses that were similarly exposed but did not undergo bypass.

METHODS

Twenty-six Western Cross sheep fetuses (median 122 days gestation) were randomly assigned to undergo cardiac bypass for 30 minutes with the Hemopump circuit (n = 8), to undergo bypass for 30 minutes with the conventional (roller pump) circuit (n = 10), or to undergo identical exposure and cannulation but not bypass (n = 8, controls). Blood samples were collected to measure white cell count and differential, and C3a and lactoferrin levels prior to bypass, at the end of bypass, and 1 and 2 hours after bypass. Hemodynamics and blood gases were also monitored.

RESULTS

There was a fall in white cell count over time that continued after bypass in all groups; neutrophils and lymphocytes were affected similarly. C3a levels rose significantly from prebypass to postbypass in the roller pump group (p<0.0001) but not in either of the other groups. Lactoferrin levels rose significantly from start of bypass in both bypass groups (Hemopump p = 0.01; roller pump p<0.0001) but not in controls. The elevation in lactoferrin level coincided with worsening placental gas exchange and deteriorating cardiac function.

CONCLUSIONS

Complement and neutrophil activation occurred with fetal cardiac bypass but only neutrophil activation mirrored the FPU and cardiac dysfunction, suggesting that products of neutrophil activation may be important contributing factors. Improved FPU function with a bypass circuit that has less extracorporeal surface and does not require a large priming volume may be due in part to a reduction in the magnitude of this inflammatory response.

Double-chambered right ventricle presenting in adulthood

BACKGROUND

Double-chambered right ventricle is a form of right ventricular outflow tract obstruction that develops over time, often in patients with an abnormally short distance between the moderator band and pulmonary valve. This lesion typically presents in childhood or adolescence and is often accompanied by a ventricular septal defect. Only a handful of previous cases have been described in which double-chambered right ventricle occurred in adulthood.

METHODS

Since 1992, three patients more than 30 years old (38, 43, and 66 years of age) have presented at our institution with unusual symptoms or a previous incorrect diagnosis. We reviewed the clinical data in these patients.

RESULTS

Presenting symptoms included syncope, angina, and severe dyspnea resembling pulmonary hypertension. In 1 patient, disease was categorized as New York Heart Association class IV, and in the other 2 as class III. Coexisting anomalies included a patent foramen ovale or secundum atrial septal defect in 2 patients, a small ventricular septal defect in 1 (with a probable history of ventricular septal defect in another), and mild aortic regurgitation in 1. All patients required urgent or emergent operations, with peak pressures in the proximal right ventricular chamber of 135 to 180 mm Hg and severely depressed left ventricular function in 1 patient. Resection of the anomalous right ventricular muscle bundles was achieved through a right atrial approach in all patients. All patients were alive with improved functional status at follow-up, which was between 15 and 40 months.

CONCLUSIONS

Right ventricular outflow tract obstruction resulting from a double-chambered right ventricle is rare in adults, but when it does occur it can present with unusual symptoms. When evaluating the patient with signs or symptoms of primary right heart failure, cardiologists should make an effort to image the entire right heart complex. Subcostal echocardiography can facilitate adequate visualization of the right ventricle when it is difficult to distinguish the subpulmonary outflow tract from the parasternal and apical windows.

Coronary to pulmonary artery collaterals in patients with pulmonary atresia and ventricular septal defect

BACKGROUND

The frequency, distribution, and surgical importance of coronary artery to pulmonary artery (CAPA) collaterals have not been established. The aim of this study was to establish prevalence, anatomical pattern, and significance of CAPA in patients with pulmonary atresia and ventricular septal defect (PA/VSD).

METHODS

We reviewed cardiac catheterization and operative data of 87 consecutive, unselected patients who underwent one-stage complete unifocalization for PA/VSD and assessed major systemic to pulmonary collaterals from July 1992 to June 1998.

RESULTS

CAPA collaterals were diagnosed in 9 of 87 patients (10%). The collaterals originated from the left coronary artery system in 7 patients and the right in 2. Collaterals from the left coronary system arose from the left main coronary artery in 3 patients and the circumflex in 4. All collaterals joined the central pulmonary artery, which bifurcated and supplied both lungs. One collateral from the right coronary system joined the stump of the main pulmonary artery and the other gave origin to a true left pulmonary artery, which was the sole supply to 75% of the left lung. Coronary artery enlargement was seen in 2 patients only. No patient had evidence of myocardial ischemia. Coronary collaterals comprised a dual source of pulmonary blood flow in all but 1 patient. During unifocalization, the CAPA collaterals were ligated at its origin in all cases, and the collateral from the right coronary to the left pulmonary artery was unifocalized.

CONCLUSIONS

The prevalence of CAPA collaterals in patients with PA/VSD is approximately 10%. The diagnosis may be missed without appropriate angiograms. We recommend selective ascending aortogram or selective coronary angiogram in all patients.

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.

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.

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.

Incidence and implications of systemic to pulmonary collaterals after bidirectional cavopulmonary anastomosis

BACKGROUND

Systemic to pulmonary arterial collaterals often develop after bidirectional cavopulmonary anastomosis (BCPA). It has been proposed that such collaterals may be related to perioperative outcome and duration of effusions after the modified Fontan procedure. However, the incidence and significance of collaterals after BCPA remain uncertain.

METHODS

To evaluate risk factors for, and significance of, such collaterals, we reviewed angiographic and clinical data for all 76 patients who underwent BCPA between January 1990 and June 1996 and had follow-up catheterization during or before 1997.

RESULTS

The median age at BCPA was 10 months, and the median duration from BCPA to follow-up catheterization was 18 months. Arterial collaterals were detected on follow-up catheterization in 45 patients (59%). Factors associated with collateral development included a prior right-sided systemic-to-pulmonary arterial shunt, lower pre-BCPA end-diastolic ventricular pressure and pulmonary vascular resistance, and use and duration of cardiopulmonary bypass during the BCPA operation. Fourteen of the 45 patients (30%) underwent coil embolization of the collaterals. Forty-three patients have undergone extracardiac conduit Fontan, with 1 early and 1 late death. Collaterals were present in 22 of these patients, 7 of whom underwent pre-Fontan embolization. The duration from BCPA to Fontan was longer in patients with collaterals, but these patients were not more likely to have prolonged effusions than those without, and the duration of tube thoracostomy was significantly shorter in patients with collaterals. Embolization of collaterals did not affect the duration of effusions.

CONCLUSIONS

Systemic-to-pulmonary arterial collaterals are common after BCPA. In contrast to prior reports, collaterals were not associated with a higher incidence of prolonged effusions after the Fontan procedure in our experience, and did not correlate with poor outcome.

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)