Infective endocarditis in patients after percutaneous pulmonary valve implantation with the stent-mounted bovine jugular vein valve: Clinical experience and evaluation of the modified Duke criteria

AIMS

Percutaneous pulmonary valve implantation (PPVI) has proven good hemodynamic results. As infective endocarditis (IE) remains a potential complication with limited available clinical data, we reviewed our patient records to improve future strategies of IE prevention, diagnosis and treatment.

METHODS

Medical records of all patients diagnosed with Melody® valve IE according to the modified Duke criteria were retrospectively analyzed in three Belgian tertiary centers.

RESULTS

23 IE episodes in 22 out of 240 patients were identified (incidence 2.4% / patient year) with a clear male predominance (86%). Median age at IE was 17.9 years (range 8.2-45.9 years) and median time from PPVI to IE was 2.4 years (range 0.7-8 years). Streptococcal species caused 10 infections (43%), followed by Staphylococcus aureus (n = 5, 22%). In 13/23 IE episodes a possible entry-point was identified (57%). IE was classified as definite in 15 (65%) and as possible in 8 (35%) cases due to limitations of imaging. Echocardiography visualized vegetations in only 10 patients. PET-CT showed positive FDG signals in 5/7 patients (71%) and intracardiac echocardiography a vegetation in 1/1 patient (100%). Eleven cases (48%) had a hemodynamically relevant pulmonary stenosis at IE presentation. Nine early and 6 late percutaneous or surgical re-interventions were performed. No IE related deaths occurred.

CONCLUSIONS

IE after Melody® valve PPVI is associated with a relevant need of re-interventions. Communication to patients and physicians about risk factors is essential in prevention. The modified Duke criteria underperformed in diagnosing definite IE, but inclusion of new imaging modalities might improve diagnostic performance.

Clumping factor A, von Willebrand factor-binding protein and von Willebrand factor anchor Staphylococcus aureus to the vessel wall

Essentials Staphylococcus aureus (S. aureus) binds to endothelium via von Willebrand factor (VWF). Secreted VWF-binding protein (vWbp) mediates S. aureus adhesion to VWF under shear stress. vWbp interacts with VWF and the Sortase A-dependent surface protein Clumping factor A (ClfA). VWF-vWbp-ClfA anchor S. aureus to vascular endothelium under shear stress.

SUMMARY

Objective When establishing endovascular infections, Staphylococcus aureus (S. aureus) overcomes shear forces of flowing blood by binding to von Willebrand factor (VWF). Staphylococcal VWF-binding protein (vWbp) interacts with VWF, but it is unknown how this secreted protein binds to the bacterial cell wall. We hypothesized that vWbp interacts with a staphylococcal surface protein, mediating the adhesion of S. aureus to VWF and vascular endothelium under shear stress. Methods We studied the binding of S. aureus to vWbp, VWF and endothelial cells in a micro-parallel flow chamber using various mutants deficient in Sortase A (SrtA) and SrtA-dependent surface proteins, and Lactococcus lactis expressing single staphylococcal surface proteins. In vivo adhesion of bacteria was evaluated in the murine mesenteric circulation using real-time intravital vascular microscopy. Results vWbp bridges the bacterial cell wall and VWF, allowing shear-resistant binding of S. aureus to inflamed or damaged endothelium. Absence of SrtA and Clumping factor A (ClfA) reduced adhesion of S. aureus to vWbp, VWF and activated endothelial cells. ADAMTS-13 and an anti-VWF A1 domain antibody, when combined, reduced S. aureus adhesion to activated endothelial cells by 90%. Selective overexpression of ClfA in the membrane of Lactococcus lactis enabled these bacteria to bind to VWF and activated endothelial cells but only in the presence of vWbp. Absence of ClfA abolished bacterial adhesion to the activated murine vessel wall. Conclusions vWbp interacts with VWF and with the SrtA-dependent staphylococcal surface protein ClfA. The complex formed by VWF, secreted vWbp and bacterial ClfA anchors S. aureus to vascular endothelium under shear stress.

20 years of arterial switch operation for simple TGA

BACKGROUND

Arterial switch operation became the golden treatment for simple transposition of the great arteries (sTGA). We describe our experience with the arterial switch operation regarding long-term outcome and the need for re-intervention. Nevertheless, supravalvular pulmonary stenosis (SPS) remains a concern in the long run. We assess the evolution of SPS over time and evaluate the effect of technical modifications on SPS during our experience.

METHODS

We performed a retrospective study on 133 patients operated with ASO for TGA between October 1991 and November 2009. Last report method was used. We reviewed our pediatric cardiology and cardiac surgery database to examine the echocardiographic data and electrocardiograms. A mean follow-up of 9.2 years (+/- 5.83 SD) was reached.

RESULTS

One (0.8%) patient deceased postoperatively due to cardiogenic shock. The overall actuarial freedom from reoperation (open and percutaneous) was 88.1%, 78.5% and 76.9% at 1, 5 and 10 years. SPS needed to be treated in 17 patients. Valve regurgitation at final investigation was maximal moderate in 5 patients for the aortic valve, 10 for pulmonary valve and 3 in tricuspid valve.

CONCLUSIONS

ASO shows excellent long-term results in sTGA with a very low morbidity and mortality and is therefore the procedure of choice. Re-intervention rate is determined by SPS. Since the extensive mobilization of the pulmonary arteries and the creation of a longer neo-pulmonary root, reduction in SPS was seen with no re-interventions in the second half of the group. To obtain a final comparison with the atrial switch operation, a longer Follow-up is necessary.

Efficacy and outcome of intensive care in pediatric oncologic patients

OBJECTIVE

Because the long-term survival of children with cancer has dramatically improved because of multimodal treatment strategies, intensive care medicine has become more relevant for these patients. This study was performed to assess the efficacy of intensive care medicine in newly diagnosed pediatric oncologic patients and in patients under ongoing oncologic treatment.

DESIGN

A retrospective analysis of children admitted to the pediatric intensive care unit (PICU) of the University Hospital Duesseldorf for life-threatening conditions between 1995 and 1999 was performed to identify those patients with an oncologic condition.

SETTING

University hospital.

PATIENTS

A total of 123 patients were identified. Children admitted for uncomplicated postoperative care and children admitted after bone marrow transplantation were excluded from this analysis. Forty-eight patients could be divided into two groups. Group A contained children admitted to the PICU at the time of cancer diagnosis and group B children receiving ongoing oncologic treatment.

INTERVENTIONS

The evaluation included diagnosis, risk factors, complications leading to PICU admission, PICU therapy, and outcome. Statistical analysis included evaluation of Pediatric Risk of Mortality (PRISM) and Therapeutic Intervention Scoring System (TISS) scores.

MEASUREMENTS AND MAIN RESULTS

Respiratory insufficiency was the leading diagnosis for PICU admission, whereas in the remaining children cardiovascular insufficiency, renal failure, neurologic impairment, ileus, and tumor-associated complications led to PICU admission. The number of organ failures was correlated to outcome. All children but one of group A could be discharged from the PICU, whereas 12 of 35 children in group B died, despite intensive care treatment attempts. The PRISM and TISS scores at admission to the PICU were significantly higher in children who did not survive the period of intensive care treatment in group B. However, all patients with a PRISM score of >20 died.

CONCLUSIONS

Diagnosis of cancer does not exclude potential benefit from intensive care medicine in these children, although severe complications might affect the prognosis.

Introduction of the oncological pediatric risk of mortality score (O-PRISM) for ICU support following stem cell transplantation in children

Prognostic scoring systems based on physiological parameters have been established in order to predict the outcome of ICU patients. It has been demonstrated that the predictive value of these scores is limited in patients following hematopoietic stem cell transplantation (HSCT). Therefore, we evaluated patients from the Düsseldorf pediatric stem cell transplantation center with regard to predisposing factors and prognostic variables for ICU treatment and outcome. Between January 1989 and December 1998, 180 HSCT have been performed. The clinical, laboratory and HSCT-related parameters such as conditioning treatment, engraftment, GVHD, infections and HSCT toxicity were prospectively recorded and retrospectively analyzed. Established pediatric scoring systems (PRISM, TISS, P-TISS) were applied. Twenty-eight patients required intensive care (16 male, 12 female, median age: 10.9 years (range: 0.4 to 18.9 years), five autologous, 13 allogeneic-related and 10 unrelated transplanted patients). Ventilator-dependent respiratory failure was the most frequent cause of admission to the ICU (n = 23). Fourteen of 28 patients were discharged from ICU, and six of 28 patients achieved a long-term survival (110 to 396 weeks). At admission to the ICU, impaired cardiovascular status, high CRP levels and presence of macroscopic bleeding were each associated with fatal outcome (P < 0.05). The Pediatric Risk of Mortality (PRISM) score was not prognostically significant at the 0.05 level. Long-term survival after discharge from the ICU correlated with HSCT-related parameters such as the type of transplant and severity of GVHD (P = 0.002). By introduction of HSCT related parameters such as severity of GVHD (grade 2: 2 points; grade >2: 4 points), CRP-level (>10 mg/dl: 4 points), and presence of macroscopic bleeding (4 points) into the PRISM score a new oncological PRISM ('O-PRISM') score was established. This score significantly correlated with the risk of mortality in the ICU (P = 0.01). In conclusion, the new O-PRISM score accurately characterizes the clinical situation of children requiring ICU treatment following HSCT. It distinguishes more appropriately between success and failure of ICU treatment following HSCT than the standard prognostic scores. It needs to be evaluated in future prospective studies of critically ill children after HSCT. Bone Marrow Transplantation (2000).

Mid-term follow-up after multiple system organ failure following cardiac surgery in children

Multiple system organ failure after cardiac surgery in children is a severe complication with unknown mid- and long-term sequelae. We therefore evaluated 11 children (aged 20-126 mo, median: 67 mo) having survived multiple system organ failure after cardiac operations for congenital cardiac defects in a cross-sectional follow-up study 12-76 mo (median: 32 mo) after surgery. Clinical and laboratory examinations included cardiac, pulmonary, renal, hepatic, neurological and psychological function tests. All patients had adequate cardiac function. Lung mechanics were abnormal in three children and glomerular renal function was abnormal in two patients. Slight elevation of gamma-glutamyl transpeptidase and coagulation factor deficiency was present in six and seven patients, respectively (five of whom had undergone the Fontan operation). Severe neurological sequelae such as diplegia (n = 1) and mental retardation (n = 1) were observed in two patients. In addition, five children presented delayed motor, graphomotor and/or speech development. Two children were found to have abnormal intelligence. We conclude that with the exception of neurological impairment, mid-term sequelae of multiple system organ failure after cardiac surgery in children are mild. However, longer follow-up using an appropriate control group is mandatory.

Hepatic veno-occlusive disease with severe capillary leakage after peripheral stem cell transplantation: treatment with recombinant plasminogen activator and C1-esterase inhibitor concentrate

Severe veno-occlusive disease (VOD), characterised by elevated serum bilirubin levels, is a known complication in the first 3 weeks after peripheral blood stem cell transplantation (PBSCT). Severe VOD is associated with capillary leakage and multiple organ dysfunction and leads to high mortality. We report a 17-year-old male, who developed VOD with capillary leakage (CL) after allogeneic PBSCT. The patient presented with a maximum serum bilirubin of 25.4 mg/dl, weight gain (10% of baseline weight), generalized edema, cardiovascular insufficiency, complement activation, jaundice and a decreased AT and protein C functional activity. After VOD and CL were diagnosed the patient was treated with recombinant human plasminogen activator (rt-PA) and C1 esterase-inhibitor concentrate (C1-INH-C). The clinical symptoms resolved and the patient's status stabilized. The patient was in an adequate clinical state 5 months after transplantation. We noted that the combined therapy with rt-PA and C1-INH-C in this high-risk situation led to a resolution of VOD with CL.

C1 esterase inhibitor concentrate for capillary leakage syndrome following bone marrow transplantation

The prognosis of patients with severe capillary leakage syndrome (CLS) after bone marrow transplantation (BMT) is dismal despite aggressive use of intensive care therapy. Because the activated classical pathway of complement and relatively low levels of C1 esterase inhibitor (C1 INH) activity are known features in these patients, we evaluated the efficacy of a therapy using purified, human C1 INH concentrate. Severe CLS was defined as increase in body weight by more than 3% within 24 h combined with generalized edema, impaired hemodynamic system (tachycardia and/or decreased blood pressure), and non-responsiveness to furosemide. Of 142 patients, 22 developed severe CLS. The first seven patients whom we diagnosed with this complication were assessed as control patients. Fifteen patients with severe CLS were treated with C1 INH concentrate using a cumulative dose of 180 units/kg body wt. (initial dose: 60 units/kg, followed by two doses at 30 units/kg and four doses at 15 units/kg, every 12 h). The survival rate of patients with CLS was 57% at 1 year after BMT in the C1 INH treatment group, compared with 14% in the control group (p = 0.008). Eight of 15 treated patients are alive at a median of 9 months (range: 4-55) after BMT. The plasma levels of the complement activation parameters C4d and C5a were 3 +/- 1.1 mg/dl (mean +/- S.D.) and 0.3 +/- 0.1 microgram/l, respectively, prior to BMT, increasing to 8.2 +/- 2.1 mg/dl and 1.3 +/- 0.4 micrograms/l, respectively, at diagnosis of CLS. After infusion of C1 INH concentrate the plasma levels of C5a and C4d normalized. The activity of C1 INH rose to 139 +/- 10% of normal human plasma NHP pool (mean +/- S.D.) after infusion. The CH50 values were not significantly altered. The fluid status normalized within 11 days in 14 of 15 treated patients. The results of this study suggest that therapy with C1 INH concentrate improves the prognosis of patients with CLS after BMT. This has to be confirmed in a randomized, controlled trial.