Repair Of Congenital Heart Lesions Research Articles

Early extubation after cardiac operations in neonates and young infants

Objective: This study was undertaken to determine the feasibility of early extubation of the neonate and young infant after surgical repair of congenital heart lesions. Methods: The records of all patients less than 90 days of age who had cardiac operations over a 1-year period were reviewed. During this time, all patients were managed as potential candidates for early extubation. Fifty-six patients are included with a mean age of 32 ± 31 days and a mean weight of 3.7 ± 0.9 kg. Results: Twenty-eight patients (50%) were extubated in the operating room or within 3 hours after arriving in the intensive care unit. This included 38% of patients less than 7 days of age, 50% of patients 8 to 30 days of age, 44% of patients 31 to 60 days of age, and 69% of patients 61 to 90 days of age. Three patients (11%) extubated early required reintubation. No deaths were related to early extubation. Only one patient was negatively affected by early extubation. Patients extubated early had shorter stays in the intensive care unit (3.3 ± 3.9 vs 6.7 ± 2.9 days) and shorter postoperative hospital stays (5.9 ± 3.3 vs 13.5 ± 9.7 days), as well as lower intensive care unit ($5,851 ± $7,225 vs $12,064 ± $4,419) and total hospital ($21,108 ± $14,941 vs $31,608 ± $9,861) costs than patients who were ventilated. Conclusions: Early extubation can be accomplished safely in many neonates and young infants undergoing cardiac operations for repair of congenital heart defects and can shorten hospital stay and reduce costs. (J Thorac Cardiovasc Surg 1997;114:413-8)

The influence of cardiopulmonary bypass on ionized magnesium in neonates, infants, and children undergoing repair of congenital heart lesions.

The purpose of this study was to measure the ionized magnesium (iMg) concentrations in children undergoing the correction of congenital heart defects. iMg levels were measured in 115 consecutive patients at five sample periods: prebypass, onset of bypass, during rewarming, immediately postbypass, and 1 h postbypass using an ion-selective electrode of the NOVA-CRT 8 (Nova Biomedical, Watham, MA). The incidence of dysrythmias was noted. Patients were divided into two groups: those who received Plegisol as the cardioplegic solution and those who did not. This study demonstrates that iMg decreases with the onset of cardiopulmonary bypass (CPB) in patients who weigh < 10 kg. In the Plegisol group, all subgroups of patients demonstrated statistically higher iMg during the rewarming phase of CPB, immediately post-CPB, and 1 h post-CPB, when compared with control values. The probability of dysrhythmias in the Plegisol group was almost twice that of the non-Plegisol group. However, this did not reach statistical significance (P = 0.22). The results of our study demonstrate that the use of CPB on pediatric patients produces alterations in the iMg. The changes differ depending on both patient weight and the use of a magnesium-containing cardioplegic solution, exemplified here by Plegisol. The role of these changes in iMg on dysrhythmias could not be further evaluated.

The Influence of Cardiopulmonary Bypass on Ionized Magnesium in Neonates, Infants, and Children Undergoing Repair of Congenital Heart Lesions

The purpose of this study was to measure the ionized magnesium (iMg) concentrations in children undergoing the correction of congenital heart defects.iMg levels were measured in 115 consecutive patients at five sample periods: prebypass, onset of bypass, during rewarming, immediately postbypass, and 1 h postbypass using an ion-selective electrode of the NOVA-CRT 8[TM] (Nova Biomedical, Watham, MA). The incidence of dysrythmias was noted. Patients were divided into two groups: those who received Plegisol[R] as the cardioplegic solution and those who did not. This study demonstrates that iMg decreases with the onset of cardiopulmonary bypass (CPB) in patients who weigh <10 kg. In the Plegisol[R] group, all subgroups of patients demonstrated statistically higher iMg during the rewarming phase of CPB, immediately post-CPB, and 1 h post-CPB, when compared with control values. The probability of dysrhythmias in the Plegisol[R] group was almost twice that of the non-Plegisol[R] group. However, this did not reach statistical significance (P = 0.22). The results of our study demonstrate that the use of CPB on pediatric patients produces alterations in the iMg. The changes differ depending on both patient weight and the use of a magnesium-containing cardioplegic solution, exemplified here by Plegisol[R]. The role of these changes in iMg on dysrhythmias could not be further evaluated. (Anesth Analg 1997;84:497-500)

Nursing Implications of Interventional Device Placement in Pediatric Cardiology and Pediatric Cardiac Surgery

The use of interventional devices to complete or augment repair of congenital heart lesions capitalizes on the collaborative skills of the cardiovascular team: cardiology, cardiovascular surgery, and nursing. Placement of devices, eliminating the requirement for surgical intervention, places new demands on nursing staff regarding patient and family preparation. Supporting families, if the inability to place a device occurs, is a critical function of the nursing staff. The experimental nature of the devices and the complexity of the disease places additional stress on the family and increases the demands of postimplantation nursing care.

Intraoperative Transesophageal Echocardiography for the Detection of Cardiac Preload Changes Induced by Transfusion and Phlebotomy in Pediatric Patients

Intraoperative blood volume changes are difficult to monitor in pediatric patients. The authors tested the hypothesis that transesophageal echocardiography would identify changes in cardiac filling resulting from manipulations of blood volume. Eleven patients (3-15 kg) were studied following sternal closure after repair of congenital heart lesions. Transesophageal echocardiography of the midpapillary left ventricular short axis view and hemodynamics were recorded at baseline (T1), during withdrawal of blood until the systolic blood pressure decreased by 5 mmHg (T2) and 10 mmHg (T3), and after reinfusion of the blood (T4). The identical cycle of blood withdrawal and reinfusion was repeated after administration of calcium chloride (10 mg/kg; T5-T8). Manually traced transesophageal echocardiography images of the left ventricular end-diastolic area decreased from 4.64 +/- 1.50 cm2 at T1 to 4.03 +/- 1.25 cm2 at T2 to 3.78 +/- 1.35 cm2 at T3, and increased to 4.42 +/- 1.75 cm2 at T4. Nearly identical results were obtained at T5-T8. End-systolic areas significantly decreased from 1.96 +/- 0.86 cm2 at T1 to 1.52 +/- 0.73 cm2 at T2 to 1.41 +/- 0.62 cm2 at T3, and increased to 1.87 +/- 0.88 cm2 at T4. An experienced anesthesiologist-echocardiographer blinded to study events was able to identify mild reductions in blood volume (T2, T3, T6, T7) from recorded cine-loop video recordings with high sensitivity (80-95%) and specificity (80%). Transesophageal echocardiography is a potentially useful monitor of cardiac filling changes in pediatric patients.

Intraoperative Echocardiography for Evaluation of Congenital Heart Defects in Infants and Children

To determine the accuracy, utility, and limitations of intraoperative transesophageal echocardiography (TEE) in infants and children, we performed prebypass and postbypass TEE in 90 children undergoing surgical repair of congenital heart lesions, comparing the results to those obtained using intraoperative epicardial echocardiography and pre- and postoperative precordial echocardiography. Patients ranged in age from 4 days to 21 yr (mean 4.1 yr) and in weight from 3 to 68 kg (mean 15.4 kg). Prebypass, we obtained high-quality, two-dimensional TEE images in 86 patients, with correction of the preoperative precordial diagnosis in 3 and confirmation of the preoperative diagnosis in the rest. Adequate epicardial images were obtained in 78 patients, with confirmation of the preoperative diagnosis in all. Shunt lesions that were well delineated prebypass by both TEE and epicardial imaging included interatrial, interventricular, and atrioventricular septal defect lesions. TEE failed to detect the exact size and location of lesions involving the right ventricular outflow tract, i.e., doubly committed subarterial (supracristal) ventricular septal defects. Regurgitant lesions (n = 30) were identified and their severity evaluated in all patients by both TEE and epicardial imaging. Obstructive lesions (n = 33), excluding those involving the right ventricular outflow tract, were well defined by both echocardiographic approaches. Postbypass, we obtained high-quality, two-dimensional, color and Doppler TEE images in 86 patients and epicardial images in 78 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Use of the Constrained Vortex Pump in Children Under 20 kg

Since the inception of the constrained vortex pump, much controversy has arisen over its use during cardiopulmonary bypass (CPB). Centrifugal pumps used during pediatric perfusion requiring low flow rates have been cited with increased hemolysis and fluctuating flow rates. At the Medical College of Virginia Hospitals, 209 children weighing &lt;20 kg have been placed on CPB utilizing the BioMedicus BP 50 pump. This study describes the technique and evaluates pump induced hemolysis by measuring plasma free hemoglobin (PFH) production. Five consecutive pediatric patients, age 0.2-48 months, (2.8-12.8 kg.) undergoing CPB for repair of heart defects at MCVH were studied using the BioMedicus BP 50 pump head. Potential for stagnant areas of flow were avoided during weaning from CPB by decreasing rpms to a minimum of 1800 and controlling flows with screw clamps on both arterial and venous lines to further reduce and terminate CPB. Plasma free hemoglobin samples were drawn prior to bypass, 30 minutes, 8 hrs, and 24 hrs post-CPB. PFH was determined by the Perkins-Elmer Spectrophotometer method. Results showed an expected rise in PFH immediately post-CPB, and all but one patient returned to baseline levels within 8 hrs. None of the 209 pediatric patients managed thus far at MCV utilizing the BP 50 pump head have exhibited clinical evidence of renal damage due to generation of plasma free hemoglobin. The authors conclude that pediatric patients requiring CPB for repair of congenital heart lesions can be safely perfused using a constrained vortex pump.

Routine use of intraoperative epicardial echocardiography and Doppler color flow imaging to guide and evaluate repair of congenital heart lesions: A prospective study

Routine epicardial two-dimensional echocardiography, Doppler, and Doppler color flow imaging studies were performed before and after cardiopulmonary bypass in 328 patients undergoing operations for congenital heart disease. Ages ranged from 1 day to 59 years (mean 5.9 years); the smallest patient was 1.8 kg. Complete examinations were conducted in 3.6 +/- 1.7 minutes. Prebypass examinations demonstrated previously unappreciated details of anatomy in 60 patients (18%), which did not relate to whether catheterization had been performed, and they were believed to play a role in surgical planning in 143 patients (44%). Discovery of previously unrecognized features of anatomy increased the impact of echo-Doppler color flow imaging on operative planning by 2.5 times. After bypass, echo-Doppler color flow imaging disclosed unsuspected residual defects in 22 patients (7%) who were doing well clinically and enabled an attempt at immediate revision of the procedure. When ultimate clinical outcome was compared to postbypass findings of echo-Doppler color flow imaging, the presence of a residual defect, right or left ventricular dysfunction, or any concern with the heart by echo-Doppler color flow imaging appeared to serve as a predictor of unfavorable outcome (p less than 0.001 for each when compared with absence of these difficulties). Thus routine intraoperative echo-Doppler color flow imaging is useful in aiding the planning, conduct, and assessment of results in operations for congenital heart disease.

Rapid cooling contracture of the myocardium: The adverse effect of prearrest cardiac hypothermia

Hypothermic total circulatory arrest for repair of congenital heart lesions in neonates requires a period of rapid core cooling on cardiopulmonary bypass during which the myocardium is also exposed to hypothermic perfusion. Myocardial hypothermia in the nonarrested state results in an increase in contractility due to elevation of intracellular calcium levels. This study was designed to test the hypothesis that rapid myocardial cooling before cardioplegic ischemic arrest results in damage, with impaired recovery during reperfusion. Two groups of 10 rabbit hearts were perfused on an isolated Langendorff apparatus. Group N (normothermia) was perfused at 37 degrees C before 2 hours of cardioplegic ischemic arrest at 10 degrees C. Group C (cooling) was perfused at 15 degrees C in the unarrested state for 20 minutes before the same cardioplegic arrest conditions as group N. Left ventricular isovolumic pressure measurements, biochemical measurements from right ventricular biopsy specimens, and ventricular necrosis as defined by tetrazolium staining were used to compare the groups at 30 and 60 minutes of normothermic reperfusion. Developed pressure at a constant volume was preserved in group N at 90.7 +/- 4.5 mm Hg versus 76.9 +/- 6.3 in group C after reperfusion (p less than 0.05). Diastolic compliance showed significant deterioration in group C, with marked elevation of diastolic pressure during reperfusion (group N = 6.8 +/- 2.5 mm Hg versus group C = 38.9 +/- 6.1 after reperfusion; p less than 0.001). Adenosine triphosphate levels were significantly higher in group N both at end-ischemia and after reperfusion versus group C (group N = 17.0 +/- 1.1 nmol/mg protein versus group C = 7.7 +/- 1.0 after reperfusion; p less than 0.001). Group N had 0.4% +/- 0.4% necrosis of ventricular mass versus 19.3% +/- 2.2% with prearrest cooling in group C (p less than 0.0001). These results indicate that, when combined with cardioplegic ischemic arrest, rapid myocardial cooling in the unarrested state results in significant damage. The mechanism may be related to the cytosolic calcium loading effect of hypothermia that is not relieved during the subsequent period of cardioplegic arrest. Although hypothermia is an essential component to ischemic preservation, rapid cooling contracture can adversely influence cardioplegic myocardial protection.

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.

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.

Stress evaluation after repair of congenital heart lesions

Stress evaluation after repair of congenital heart lesions

Influence of operations with cardiopulmonary bypass on polymorphonuclear leukocyte function in infants

To determine the effect of operations with cardiopulmonary bypass on the immunologic function of polymorphonuclear leukocytes in infants, we studied polymorphonuclear leukocyte function and immunologic profile in 16 infants undergoing repair of congenital heart lesions. An oxygen/air/high-dose fentanyl anesthetic was used for all patients. Absolute neutrophil count increased significantly (p less than 0.05) after bypass and remained increased 48 hours afterward. Chemotaxis, random migration of polymorphonuclear leukocytes, and phagocytic index were unaffected, but bactericidal capacity decreased significantly immediately after cardiopulmonary bypass and remained decreased 48 hours later. Serum opsonizing capacity to bacterial and fungal antigens was variably altered, and complement factors 3 and 4 decreased significantly after cardiopulmonary bypass. Total hemolytic complement decreased significantly immediately after cardiopulmonary bypass and returned to normal by 48 hours. These data suggest that operations with cardiopulmonary bypass in infants significantly affect the immunologic function of polymorphonuclear leukocytes and result in consumption of complement.

Breast and Pectoral Muscle Maldevelopment after Anterolateral and Posterolateral Thoracotomies in Children

Anterolateral and posterolateral thoracotomies, involving an incision through the third and fourth intercostal space, have been used for the repair of congenital heart lesions in children during the past thirty years. We examined 28 patients who had undergone repair of atrial septal defect, patent ductus ateriosus, and coarctation of the aorta as children, through the anterolateral or posterolateral chest approach. Volumes of the breasts and pectoral muscles were obtained by a method using plaster molds, and linear dimensions of each chest side were measured. Questionnaires were completed that delineated the patients' perception of asymmetry of the chest. Infant breast tissue on cadavers was examined. We conclude that standard anterolateral thoracotomies result in a high frequency of breast or pectoral maldevelopment; 60% of our patients had a greater than 20% difference in volume between the two sides. We propose a modified operative approach that we believe will reduce the frequency of maldevelopment.

Developmental progress after cardiac surgery in infancy using hypothermia and circulatory arrest.

Seventy-two of 76 long-term survivors who had surgical repair of congenital heart lesions at 11 days to 26 months of age using profound hypothermia and circulatory arrest underwent psychometric testing (Stanford-Binet) late postoperatively. The mean IQ of the 72 patients was 92.9 +r16.5 (SD). Stanford-Binet scores bore no relationship to the duration of circulatory arrest or other aspects of surgical technique. Scores were significantly lower in those who had a low birth weight for gestational age, important neurologic problems preoperatively or were in the lower socioeconomic classes. An "ideal" control group of 69 children randomly selected from patients satisfying certain criteria based on birth and neonatal characteristics had a mean IQ of 106.2 +r11.6. Twenty-five patients who had surgical treatment of cogenital heart disease met the criteria for the control group except for their heart lesions. Their mean IQ was 101.4 +r15.0(NS). We could not demonstrate any significant deleterious effect that could be attributed to the surgical methods. Rather, the postoperative IQ scores reflected characteristics related to individual patients.

Postoperative Mediastinal Masses: Report of Two Cases

A mediastinal mass can mimic the presence of cardiovascular disease by simulating cardiac or vascular enlargement on chest radiographs, or by compressing the heart or great vessels with resulting symptoms or signs. This problem of misdiagnosis is particularly acute in patients with prior cardiac surgery for repair of congenital heart lesions. Two such cases are reported. In addition to simulating cardiac disease, at least one, and perhaps both, were related to prior mediastinal surgery. A mediastinal mass can mimic the presence of cardiovascular disease by simulating cardiac or vascular enlargement on chest radiographs, or by compressing the heart or great vessels with resulting symptoms or signs. This problem of misdiagnosis is particularly acute in patients with prior cardiac surgery for repair of congenital heart lesions. Two such cases are reported. In addition to simulating cardiac disease, at least one, and perhaps both, were related to prior mediastinal surgery.

A valve-containing dacron prosthesis. Its use in restoring pulmonary artery-right ventricular continuity.

Total surgical repair of congenital heart lesions with pulmonary artery-right ventricular discontinuity has required a valve-containing conduit for optimum results. Excellent results have been attained by constructing a new pulmonary valve and artery using human aortic homografts. Certain disadvantages have been noted: difficulty in procurement, limited tissue for tailoring of the prosthesis, difficulty in prevention of distortion, and early calcification of the conduit. A dacron conduit containing a porcine heterograft aortic valve that does not possess these disadvantages has now been used in five patients for construction of pulmonary artery-right ventricular continuity. This conduit is a uniform product, available in multiple sizes. Follow-up data of up to two years including postoperative catheterization studies demonstrate this prosthesis to be a satisfactory and perhaps a superior alternative to the aortic homograft for restoring pulmonary artery-right ventricular continuity.

PROGNOSIS OF COMPLETE ATRIOVENTRICULAR DISSOCIATION IN CHILDREN AFTER OPEN-HEART SURGERY

Forty patients who underwent open-heart surgery for repair of congenital heart lesions developed complete atrioventricular dissociation (3° A-V block) during operation or in the immediate postoperative period. Almost half of them maintained a hæmodynamically acceptable rhythm and rate, the majority within two weeks of surgery. Complete A-V dissociation was probably a contributing cause of death in fourteen patients (35%), but half of these also had significant residual intracardiac disease. Eight patients with persisting complete A-V dissociation remain in good health without the use of implanted cardiac pacemakers. The results suggest that in the majority of such children who survive the immediate postoperative period conduction will resume spontaneously. If residual intracardiac disease is present the prognosis for survival is much worse. Permanently implanted cardiac pacemakers should be used in children with postoperative A-V dissociation only rarely, since the outlook seems to be favourable on medical management alone.