De Vega tricuspid annuloplasty for tricuspid regurgitation in children.

BACKGROUND: Significant tricuspid valve regurgitation (TR) occurs with other congenital heart defects, typically after repair of right-sided obstructive lesions. Since 1991, we applied the De Vega tricuspid annuloplasty technique for TR in children. METHODS: Forty-one children, aged 5 months to 22.7 years (mean, 9.9 years) underwent 42 De Vega tricuspid annuloplasties for moderate or severe TR during correction of other heart defects. One child had a De Vega during primary ventricular septal defect repair. The remaining patients had prior repair of tetralogy of Fallot or pulmonary atresia, or both (19 patients), double-outlet right ventricle (6 patients), pulmonary stenosis (4 patients), pulmonary atresia and intact ventricular septum (3 patients), complete atrioventricular septal defect (3 patients), and other diagnoses (6 patients). At the time of the De Vega, 37 patients (88%) had pulmonary valve replacement or right ventricular to pulmonary artery conduit replacement. Other procedures included aortic or mitral repair or replacement (6 patients), atrial septal defect and ventricular septal defect closure (5 patients), pulmonary arterioplasty (6 patients), and tracheoplasty (1 patient). RESULTS: There were no deaths at follow-up of 3.4 +/- 2.1 years; 1 child required cardiac transplantation 17 months postoperatively. Early postrepair echocardiography quantified TR as absent or mild (34 patients; 81%), mild-to-moderate (4 patients), moderate (3 patients), and severe (1 patient). The most recent echocardiogram showed moderate TR in 11 patients and severe TR in 2 patients (both with recurrent right ventricular hypertension). One child required tricuspid valve replacement 3 years later and 1 child had redo De Vega at the time of conduit re-replacement. No other child has symptomatic TR, significant tricuspid stenosis, or De Vega-related pacemaker implantation. CONCLUSIONS: The De Vega tricuspid annuloplasty safely provides excellent relief of TR, usually in children undergoing pulmonary valve replacement or conduit replacement. Although echocardiographic TR tends to increase with time (especially with right ventricular hypertension), it rarely requires reintervention or causes symptoms.

Successful biventricular repair after initial Norwood operation for interrupted aortic arch with severe left ventricular outflow tract obstruction.

BACKGROUND: Management of newborns with interrupted aortic arch (IAA) remains challenging. Associated severe left ventricular outflow tract obstruction (LVOTO) have often led to increased mortality with neonatal biventricular repair. We review our experience with an alternative approach for this complex surgical problem. METHODS: From May 1991 to June 1999, 28 neonates were treated for IAA. Thirteen of 28 neonates (46%) had type B IAA, ventricular septal defect (VSD) and severe LVOTO (Z value -2 to -7; mean -5 +/- 1.7). Mean age was 8 days (3 to 23 days old) with average weight of 3.3 kg (2.4 to 4.2 kg). Eight of 13 (62%) had anomalous right subclavian artery. Ten of 13 (77%) had thymic aplasia and chromosome 22 region qll deletion. All 13 patients were treated initially with a modified Norwood procedure. RESULTS: There were no perioperative deaths. Complications included 2 patients with recurrent arch stenosis treated with balloon dilatation. Two patients had systemic arterial shunt revision. Follow-up ranged from 2 to 99 months old (mean 39 months). There were 2 late deaths unrelated to any operation. Nine of 12 patients had a second stage palliation consisting of a bidirectional Glenn shunt. Six patients went on to have biventricular repairs (3 Ross-Konno, 2 Rastelli, 1 VSD closure with LVOT resection). One patient had a modified Fontan operation and 5 patients are awaiting potential biventricular repair. CONCLUSIONS: Children with IAA and severe LVOTO may be managed by initial Norwood palliation with an excellent outcome likely. This initial "univentricular" approach has enabled eventual successful biventricular repair despite severe LVOTO.

Saphenous vein homograft: a superior conduit for the systemic arterial shunt in the Norwood operation.

BACKGROUND: Excessive pulmonary blood flow increases ventricular volume work in the face of inadequate systemic cardiac output, low diastolic blood pressure, and inadequate coronary perfusion. Using the smallest available 3-mm polytetrafluoroethylene shunts have been successful, although catastrophic shunt thrombosis has occasionally been observed. To avoid thrombosis with a smaller conduit, saphenous vein homografts (SVG) were used to construct the modified Blalock-Taussig (BT) shunts. METHODS: From January 1998 to April 1999, 25 patients weighing 3.1 kg (3.0 kg or less, n = 9), at a mean age of 8.9 days, underwent stage I Norwood using an SVG BT shunt. Common heart defects were aortic atresia (n = 8), mitral atresia and double-outlet right ventricle (n = 5), and unbalanced AVC (n = 5). Mean BT shunt size was 3.2 mm, with 12 patients having shunts that were 3 mm or smaller. RESULTS: Thirty-day hospital mortality was 8% (2 of 25). No shunt thrombosis was seen, despite banding the BT shunt in 3 patients. One patient had BT revision because of an anatomic issue not directly related to the shunt material. CONCLUSIONS: Excellent results may be achieved using SVG BT shunts in the Norwood operation. This conduit seems less likely to thrombose, both acutely and chronically, allowing the use of appropriately smaller-sized shunts in small neonates.

The Konno aortoventriculoplasty for repeat aortic valve replacement.

OBJECTIVE: To evaluate the outcome of aortic root augmentation by the Konno-aortoventriculoplasty technique as part of reoperative aortic valve replacement. METHODS: Since 1983, 15 patients, 12 males and three females, had repeat aortic valve replacement (AVR) with concomitant Konno aortoventriculoplasty. Age ranged from 1.2 to 18 years (mean 12.5 years). The underlying anatomic diagnoses were valve and subvalvar aortic stenosis in 11, truncal valve insufficiency in one, endocarditis in one, Shone's complex in one and severe aortic insufficiency associated with a ventricular septal defect in one patient. All patients had had previous AVR. The causes for reoperation were prosthetic valve stenosis due to growth in ten and paravalvular leak in one, homograft failure in two, xenograft failure in one, and left ventricular outflow tract obstruction (LVOTO) after mitral valve replacement in one patient. The mean size of explanted prostheses was 19.2 mm (13-23 mm) while the mean size of the implanted prostheses was 24.3 mm (19-27 mm) (P<0.01). Previous aortic root enlargement had been performed in 11 patients in conjunction with AVR. The Manougian technique was used previously in two, Konno aortoventriculoplasty in eight, and both techniques in one patient. The newly implanted aortic valves were a homograft in one patient and mechanical prostheses in 14 patients. RESULTS: There was one operative death (1 of 15 or 6.6%) in a 17.5 year old patient with previous AVR and posterior root enlargement, due to low cardiac output state. Follow-up ranged from 6 months to 17 years (mean 7.2 years). The only late death occurred in an 11.6-year-old patient due to prosthetic valve endocarditis. Two patients had complete heart block and had permanent pacemaker insertion (2 of 15 or 13.3%). One patient had pulmonary valve replacement because of combined stenosis and insufficiency 5 years after operation. All 13-surviving patients are asymptomatic at latest follow up. CONCLUSION: Konno aortoventriculoplasty with repeat AVR may be safely performed. Excellent results may be achieved despite previous aortic root enlargement. It is a good surgical option for complex LVOTO and may even reduce reoperation in children by allowing placement of a larger prosthesis.

In vivo flow dynamics of the total cavopulmonary connection from three-dimensional multislice magnetic resonance imaging.

BACKGROUND: The total cavopulmonary connection (TCPC) design continues to be refined on the basis of flow analysis at the connection site. These refinements are of importance for myocardial energy conservation in the univentricular supported circulation. In vivo magnetic resonance phase contrast imaging provides semiquantitative flow visualization information. The purpose of this study was to understand the in vivo TCPC flow characteristics obtained by magnetic resonance phase contrast imaging and compare the results with our previous in vitro TCPC flow experiments in an effort to further refine TCPC surgical design. METHODS: Twelve patients with TCPC underwent sedated three-dimensional, multislice magnetic resonance phase contrast imaging. Seven patients had intraatrial lateral tunnel TCPC and 5 had extracardiac TCPC. RESULTS: In all patients in both groups a disordered flow pattern was observed in the inferior caval portion of the TCPC. Flow at the TCPC site appeared to be determined by connection geometry, being streamlined at the superior vena cava-pulmonary junction when the superior vena cava was offset and flared toward the left pulmonary artery. Without caval offset, intense swirling and dominance of superior vena caval flow was observed. In TCPC with bilateral superior vena cavae, the flow patterns observed included secondary vortices, a central stagnation point, and influx of the superior vena cava flow into the inferior caval conduit. A comparative analysis of in vivo flow and our previous in vitro flow data from glass model prototypes of TCPC demonstrated significant similarities in flow disturbances. Three-dimensional magnetic resonance phase contrast imaging in multiple coronal planes enabled a comprehensive semiquantitative flow analysis. The data are presented in traditional instantaneous images and in animated format for interactive display of the flow dynamics. CONCLUSIONS: Flow in the inferior caval portion of the TCPC is disordered, and the TCPC geometry determines flow characteristics.

Extra-anatomic aortic bypass via sternotomy for complex aortic arch stenosis in children.

OBJECTIVE: Recurrent aortic narrowing after repair of aortic coarctation or interrupted aortic arch, as well as diffuse, long-segment aortic hypoplasia, can be difficult to manage. Extra-anatomic ascending aorta-descending aorta bypass grafting through a sternotomy is an alternative approach for this problem. METHODS: Since 1985, 19 patients aged 2 months to 18 years (mean 10.7 years) underwent extra-anatomic bypass with 10- to 30-mm Dacron grafts. The initial diagnosis was coarctation with hypoplastic arch in 15, interrupted aortic arch in 3, and diffuse long-segment aortic hypoplasia in 1. Seventeen of the children had a total of 22 previous operations: transthoracic interposition or bypass graft (n = 7), end-to-end anastomosis (n = 7), subclavian arterioplasty (n = 6), and synthetic patch (n = 2). The mean time from initial repair was 8.0 years (range 0.6-18 years). Three children had previous sternotomies. Cardiopulmonary bypass was avoided in all but 6 patients (5 with simultaneous intracardiac repairs). RESULTS: No hospital or late deaths occurred. On follow-up from 4 months to 14.7 years (mean 7.9 years), no reoperations for recurrent stenosis were performed. Two patients have arm-to-leg pressure gradients: 20 mm Hg at rest in 1 patient and a 60-mm Hg systolic exercise gradient with no resting gradient in the other. One patient required exclusion of an aortic aneurysm at the old coarctation repair site 13 years after extra-anatomic bypass. Three children had subsequent successful cardiac operations. CONCLUSIONS: Extra-anatomic bypass is an effective and relatively easy approach for selected cases of complex or reoperative aortic arch obstruction. It should be considered as an alternative operative technique for complex aortic arch reconstruction.

Diagnosis and catheter treatment of innominate artery stenosis following stage I Norwood procedure.

Four infants aged 20-115 days (mean, 57.8 days) who had undergone stage I Norwood procedure for hypoplastic left heart syndrome came to early cardiac catheterization (6-112; mean, 47.3 days) following surgery because of significant arterial desaturation (pulse oximetry indicating oxygen saturations consistently in the 40%-70% range). Cardiac catheterization demonstrated a significant systolic pressure gradient between the ascending aorta and innominate artery (30-65; mean, 51 mm Hg) as the likely cause of diminished pulmonary blood flow in these patients. Routine angiography by itself was not conclusive in identifying a discrete area of obstruction, but selective angiography coupled with a knowledge of the obstruction did reveal the stenosis. All patients were successfully treated with balloon dilatation of the stenotic area, with the pressure gradient being reduced to 7-25 (mean, 17 mm Hg) immediately following dilatation. On follow-up catheterization in three patients, the systolic gradients were 3, 6, and 9 mm Hg. Arterial oxygen saturations rose from 63.5% predilatation to 77.3% immediately postdilatation and 81% on follow-up evaluation. In conclusion, innominate artery stenosis is an important cause of diminished blood flow through a modified right Blalock-Taussig shunt. Routine angiography will often miss the diagnosis. Pressure gradients and selective angiograms are necessary in order to make the diagnosis, although careful noninvasive assessment should also be diagnostic of this problem. Catheter dilatation is therapeutic in this situation and can be performed early after surgery in the absence of a fresh suture line.

Modified Fontan without use of cardiopulmonary bypass.

BACKGROUND: Direct cavopulmonary connection using an extracardiac conduit has a number of theoretical advantages in the staged management of children with single ventricular congenital heart defects. With appropriate planning, completion Fontan using an extracardiac connection may be accomplished without the use of cardiopulmonary bypass. METHODS: From January 1995 to October 1997, 32 consecutive patients underwent completion Fontan using an extracardiac cavopulmonary connection. Twenty-one of these patients had completion Fontan without the use of cardiopulmonary bypass (No CPB group). Their postoperative outcome was retrospectively compared with a second group of 11 patients who underwent completion Fontan with an extracardiac conduit with the use of cardiopulmonary bypass. RESULTS: There was no operative or hospital mortality in either group. Early postoperative hemodynamics appear to be significantly improved in the No CPB group. Transfusion of cryoprecipitate and platelets was significantly less in the group without the use of cardiopulmonary bypass (p = 0.026, p < 0.001, respectively). Review of the most recent 12 patients also demonstrated a substantially shorter extubation time and intensive care unit stay. The length of hospital stay was significantly shorter (p = 0.036). CONCLUSIONS: Completion Fontan without the use of cardiopulmonary bypass results in improved immediate postoperative hemodynamics, and decreased use of blood and blood products. The most recent group appears to demonstrate a more rapid recovery time and shorter hospital stay (p = 0.036).

Current results with pediatric heart transplantation.

BACKGROUND: Cardiac transplantation is an accepted treatment for children with end-stage heart failure or complex or inoperable congenital defects. METHODS: Since 1988, 95 transplants have been performed in 89 children aged 4 days to 18 years (median 6.9 years, 42 patients 0-5 years). Fifty-eight (61%) had congenital or acquired heart disease, 31 (33%) had idiopathic cardiomyopathy, and 6 (6%) were retransplants. Fifty-seven of the patients had prior cardiac surgery with a range of one to eight procedures (mean 3.4 procedures/patient). At the time of transplantation, 53 (56%) were United Network for Organ Sharing (UNOS) status I, including 23 children on mechanical ventilation and 4 with mechanical circulatory support. RESULTS: Thirty-day survival in this group was 96%. Posttransplant results showed a median time of ventilation of 1 day (mean 3.0+/-5.7 days), median duration of inotropic support of 2 days (mean 2.7+/-2.3 days), median intensive care unit (ICU) stay of 4 days (mean 6.9+/-9.6 days), and median hospitalization of 9 days (mean 14.3+/-13.9 days). Follow-up from 1 month to 10.3 years (mean 3.1 years) has demonstrated a 1-year actuarial survival of 79% and a 5-year actuarial survival of 69%. Rejection, both acute and chronic, accounted for the vast majority of deaths. CONCLUSIONS: Pediatric heart transplantation can be accomplished with excellent early survival despite multiple prior cardiac operations and relative severity of illness. Parameters such as postoperative ventilation, inotropic support, ICU stay, and hospitalization can be kept at reasonable levels with acceptable long-term results, although rejection remains a serious problem.

Experience with a low profile bipolar, active fixation pacing lead in pediatric patients.

Continued miniaturization of permanent pacing systems has promoted use of this technology in younger and smaller pediatric patients. Intermedics ThinLine 438-10 active fixation pacing leads (4.5 Fr lead body) were implanted in 26 patients (17 males/9 females; 9.9 +/- 6.9 years). Twenty of 26 patients received dual chamber systems, 6 of 26 patients single lead systems. Each patient has been followed 3 months. Pacemaker analysis at implant and 6 months later evaluated pulse width thresholds at 2.5 V (atrial 0.07 +/- 0.02 vs 0.13 +/- 0.02 ms [P = 0.01]; ventricular 0.08 +/- 0.04 ms vs 0.20 +/- 0.04 ms [P = 0.01]); sensing thresholds (atrial 4.1 +/- 0.41 mV vs 4.0 +/- 4.2 mV [P = NS]; ventricular 9.7 +/- 0.72 vs 9.3 +/- 0.94 mV [P = NS]); and impedance (atrial 345 +/- 12 vs 370 +/- 120 O [P = 0.04]; ventricular 412 +/- 17 vs 458 +/- 190 O [P < 0.01]). One volt lead failed with exit block at approximately 6 weeks. The youngest (9 months to 5 years) and smallest (6.5-18.0 kg) ten patients have each shown by venography to have at least mild venous stenosis at the lead(s) insertion site; five patients demonstrated collateral formation around asymptomatic obstruction, with no thrombus formation. The Intermedics 438-10 ThinLine pacing lead has demonstrated good and stable early postimplant electrical parameters. Angiographic evaluation in our smaller patients has shown evidence for asymptomatic venous obstruction.

The pharmacokinetics of milrinone in pediatric patients after cardiac surgery.

BACKGROUND: Milrinone has been shown to increase cardiac output in children after cardiac surgery, but pharmacokinetic analysis has not been used to identify effective dose regimens. The purpose of this study was to characterize the pharmacokinetics of milrinone in infants and children and to apply the results to the issue of dosing. METHODS: Twenty children were studied after they underwent repair of congenital cardiac defects. Control hemodynamic measurement was made after the children were separated from cardiopulmonary bypass, and each patient was given a loading dose of 50 microg/kg progressively in 5 min. Hemodynamic measurements were recorded again at the end of the loading dose and when a blood sample was taken to determine milrinone plasma concentrations. Further blood samples were taken during the next 16 h for milrinone plasma concentration analysis. The pharmacokinetics of milrinone were analyzed using the population pharmacokinetic program NONMEM. RESULTS: The loading dose of milrinone resulted in a mean decrease in mean blood pressure of 12% and a mean increase in cardiac index of 18% at a mean peak plasma concentration of 235 ng/ml. The pharmacokinetics of milrinone were best described by a three-compartment model. In the optimal model, all volumes and distribution clearances were proportional to weight, and weight-normalized elimination clearance was proportional to age; ie., Cl1 = 2.5 x weight x (1 + 0.058 x age) where Cl1 is expressed as ml/min, and the units of weight and age are kg and months, respectively. CONCLUSIONS: A loading dose of 50 microg/kg effectively increases cardiac index in children after cardiac surgery. Simulations indicate that the peak plasma concentration can be maintained by following the loading dose of 50 microg/kg with an infusion of approximately 3 microg x kg(-1) x min(-1) for 30 min and then a maintenance infusion, which may require adjustment for age.

Hematologic and economic impact of aprotinin in reoperative pediatric cardiac operations.

BACKGROUND: Aprotinin consistently reduces blood loss and transfusion requirements in adults during and after cardiac surgical procedures, but its effectiveness in children is debated. We evaluated the hemostatic and economic effects of aprotinin in children undergoing reoperative cardiac procedures with cardiopulmonary bypass. METHODS: Control, low-dose aprotinin, and high-dose aprotinin groups were established with 15 children per group. Platelet counts, fibrinogen levels, and thromboelastographic values at baseline and after protamine sulfate administration, number of blood product transfusions, and 6-hour and 24-hour chest tube drainage were used to evaluate the effects of aprotinin on postbypass coagulopathies. Time needed for skin closure after protamine administration and lengths of stay in the intensive care unit and the hospital were recorded prospectively to determine the economic impact of aprotinin. RESULTS: Coagulation tests performed after protamine administration rarely demonstrated fibrinolysis but did show significant decreases in platelet and fibrinogen levels and function. The thromboelastographic variables indicated a preservation of platelet function by aprotinin. Decreased blood product transfusions, shortened skin closure times, and shortened durations of intensive care unit and hospital stays were found in the aprotinin groups, most significantly in the high-dose group with a subsequent average reduction of nearly $3,000 in patient charges. CONCLUSIONS: In children undergoing reoperative cardiac surgical procedures, aprotinin is effective in attenuating postbypass coagulopathies, decreasing blood product exposure, improving clinical outcome, and reducing patient charges.

Inflammatory cytokines (IL-1alpha, TNF-alpha) and LPS modulate the Ca2+ signaling pathway in osteoblasts.

Locally derived growth factors and cytokines in bone play a crucial role in the regulation of bone remodeling, i.e., bone formation and bone resorption processes. We studied the effect of interleukin (IL)-1alpha, tumor necrosis factor (TNF)-alpha, and Escherichia coli lipopolysaccharide (LPS) on the hormone-activated Ca2+ message system in the osteoblastic cell line UMR-106 and in osteoblastic cultures derived from neonatal rat calvariae. In both cell preparations, IL-1alpha, TNF-alpha, and LPS did not alter basal intracellular Ca2+ concentration ([Ca2+]i) but attenuated Ca2+ transients evoked by parathyroid hormone (PTH) and PGE2 in a dose (1-100 ng/ml)- and time (8-24 h)-dependent fashion. The cytokines modulated hormonally induced Ca2+ influx (estimated by using Mn2+ as a surrogate for Ca2+) as well as Ca2+ mobilization from intracellular stores. The latter was linked to suppressed production of hormonally induced inositol 1,4,5-trisphosphate. The effect of cytokines on [Ca2+]i was abolished by the tyrosine kinase inhibitor herbimycin A (50 ng/ml). The cytokine's effect was, however, independent of nitric oxide (NO) production, since NO donors (sodium nitroprusside) as well as permeable cGMP analogs augment, rather than attenuate, hormonally induced Ca2+ transients in osteoblasts. Given the stimulatory role of cytokines on NO production in osteoblasts, the disparate effects of cytokines and NO on the Ca2+ signaling pathway may serve an autocrine/paracrine mechanism for modulating the effect of calciotropic hormones on bone metabolism.

The effect of cell-matrix interaction on parathyroid hormone (PTH) receptor binding and PTH responsiveness in proximal renal tubular cells and osteoblast-like cells.

The interaction of cells with the surrounding extracellular matrix (ECM) or basement membrane (BM) brings about profound changes in cellular biological responses, such as cell differentiation, proliferation, and gene expression. We studied the effect of ECM on PTH receptor binding and on biological responses mediated by PTH, in two cell preparations: 1) the proximal tubular OK opossum kidney cell line; and 2) MC3T3-E1 cells, a clonal line of nontransformed murine osteoblasts. Cells were plated on either plastic surfaces or on tissue culture dishes coated with specific ECM components. In both cell types plated on collagen-type IV (Col-IV), PTH receptor binding, on day 4 of culture, was markedly diminished, when compared with cells on plastic (approximately 45% inhibition, P < 0.01). In addition, Col-IV dose dependently inhibited cAMP generation stimulated by PTH (P < 0.001 vs. plastic), whereas cAMP generation by PGE2, cholera toxin, and forskolin was not altered. In Northern blot analysis, a PTH/PTH-related-protein receptor messenger RNA transcript was detected in both the kidney and bone cells. However, only OK cells manifested a decreased abundance of receptor messenger RNA when plated on Col-IV, compared with plastic. The physiological significance of inhibited cAMP production by Col-IV was evaluated by measuring the influence of different matrices on the activity of Na+/H+ exchanger (NHE) in OK cells and cell mitogenic activity in MC3T3-E1 cells (both responses are negatively modulated by cAMP). OK cells plated on Col-IV showed 70% inhibition of NHE, compared with cells plated on plastic (P < 0.01). PTH inhibits NHE activity in cells on plastic but stimulates exchanger activity by 40% in cells plated on Col-IV. In MC3T3-E1 cells grown on plastic, PTH exerts a dose-dependent antiproliferative effect, which is mediated by cAMP. This effect is mitigated when cells are grown on Col-IV (40-50% less antiproliferative effect). In summary, Col-IV, a maj or BM constituent, has a profound inhibitory effect on PTH binding and PTH-mediated biological responses in both kidney tubular cells and osteoblasts. Altered cellular function by Col-IV may be of physiological relevance in states associated with altered composition of BM or expansion of ECM (e.g. diabetes mellitus and interstitial fibrosis).

Predicting and treating coagulopathies after cardiopulmonary bypass in children.

UNLABELLED: Coagulopathies in children after cardiopulmonary bypass (CPB) are complex. There are very limited data correlating coagulation tests with postoperative bleeding. We evaluated coagulation changes after CPB and after the administration of coagulation products to 75 children. Baseline coagulation tests were obtained and repeated after protamine administration, after transfusion of individual coagulation products, and on arrival in the intensive care unit (ICU). Regression analysis demonstrated no baseline coagulation test to predict postoperative chest tube drainage. Weight and duration of CPB were determined to be the only predictors of bleeding. Further analyses demonstrated that children <8 kg had more bleeding and required more coagulation products than children >8 kg. Postprotamine platelet count and fibrinogen level correlated independently with 24-h chest tube drainage in children <8 kg, whereas postprotamine platelet count and thrombelastographic values did so in patients weighing >8 kg. Platelet administration alone was found to restore effective hemostasis in many patients. With ongoing bleeding, cryoprecipitate improved coagulation parameters and limited blood loss. Fresh-frozen plasma administration after platelets worsened coagulation parameters and was associated with greater chest tube drainage and more coagulation product transfusions in the ICU. Objective data to guide post-CPB component therapy transfusion in children are suggested. IMPLICATIONS: Children <8 kg can be expected to have more severe coagulopathies, require more coagulation product transfusions, and bleed more after cardiopulmonary bypass. Correlations between coagulation tests and postoperative chest tube drainage are defined. Platelets and, if necessary, cryoprecipitate optimally restore hemostasis. Fresh-frozen plasma offers no benefits in correcting postcardiopulmonary bypass coagulopathies in children.

A comparison of the hemodynamic effects of amrinone and sodium nitroprusside in infants after cardiac surgery.

The phosphodiesterase inhibitor amrinone (AMR) increases cardiac output in children after cardiac surgery. In vitro, amrinone has both positive inotropic and vasodilatory effects. However the relative contribution of these effects to the increases in cardiac output observed clinically is unclear, and it has not been demonstrated that amrinone offers a hemodynamic advantage above that of pure vasodilators in infants. We compared the hemodynamic effects of AMR and sodium nitroprusside (SNP) in 10 infants after cardiac surgery. Cardiac index (CI) was measured by thermodilution after SNP administration, titrated to decrease mean blood pressure (MBP) by 20%, and then after a 1.5-mg/kg bolus dose of AMR. Each patient served as his or her own control. Preload, as measured by left atrial pressure and transesophageal echocardiography (in eight patients), was kept constant throughout the protocol. Both SNP and AMR caused significant decreases in MBP and systemic vascular resistance index (SVRI). However, only AMR resulted in a significant increase in CI. The ratio of fractional increase in CI to fractional absolute decrease in MBP was significantly greater for AMR than SNP, indicating greater efficacy for AMR in the treatment of low cardiac output syndrome and suggesting that, in infants after cardiac surgery, AMR has clinically relevant positive inotropic effects.

Nephrotic syndrome and renal insufficiency associated with lithium therapy.

Although the therapeutic administration of lithium in the psychiatric setting has been associated with various renal side effects, only a few reported cases have suggested a possible link to glomerular disease. We report two patients who, while taking lithium, developed heavy proteinuria caused by minimal change disease and acute renal insufficiency attributable to acute tubular necrosis. These clinical findings resolved on discontinuation of the drug, suggesting a role for lithium in their development. We also postulate that lithium, with its unique properties as a modulator of the phosphoinositol pathway, may play a key role in the pathogenesis of minimal change disease.