Bruno Murzi

Repair of congenital malformations of the mitral valve: early and midterm results.

BACKGROUND The aims of this study were to determine early and midterm survival and freedom from reoperation, and to identify the predictors for poor postoperative outcome in children undergoing mitral valve (MV) repair owing to congenital malformations of the mitral valve. METHODS Between January 1990 and February 2001, 94 consecutive children with congenital MV disease underwent valve repair. The mean age was 5.2+/-3.3 years (range 20 days to 15 years). Twenty-five (26.6%) children were less than 1 year old. Isolated MV disease was found in 21 (22.4%) patients. MV stenosis was the predominant lesion in 21 (22.4%) patients with a mean left atrial to left ventricle diastolic peak gradient of 24.5+/-9.2 mm Hg. MV regurgitation was the predominant pathophysiology in 73 (77.6%) patients with a mean regurgitation grade of 3.3+/-0.7. RESULTS The hospital mortality was 8.5% (8 of 94). Three patients required permanent pacemaker implantation owing to complete atrioventricular block. Two patients underwent mediastinal exploration for significant bleeding. Postoperatively the echocardiography color Doppler study demonstrated a significantly lower mean end diastolic left atrium to left ventricle gradient 8.7+/-2.2 mm Hg (p < 0.001) in patients with MV stenosis and a mean regurgitation grade of 0.9+/-0.6 (p < 0.001) in patients with MV regurgitation. Actuarial survival and actuarial reoperation-free survival were 89.2% and 76.3%, respectively. Multivariate analysis demonstrated that age less than 1 year (p = 0.035), hammock MV (p = 0.0093), cardiothoracic ratio greater than 0.6 (p < 0.0001), and associated cardiac anomalies (p = 0.003) were strong predictors for poor overall freedom from reoperation and midterm survival. CONCLUSIONS Mitral valve repair for congenital mitral valve disease yields acceptable early and midterm mortality and reoperation rates. Strong predictors for poor overall freedom from reoperation and midterm survival were age less than 1 year, hammock MV, cardiothoracic ratio greater than 0.6, and associated cardiac anomalies.

Thyroid hormones homeostasis in pediatric patients during and after cardiopulmonary bypass.

The concentrations of thyroid hormones were measured in 14 pediatric patients before, during, and after cardiopulmonary bypass. The ages of the patients ranged between 18 months and 14 years. Patients were kept normothermic, or moderate or deep hypothermia was induced depending on the specific pathologic condition involved. A marked reduction in the levels of total triiodothyronine, total thyroxine, free triiodothyronine, and thyroid-stimulating hormone, and in the ratio of free triiodothyronine to free thyroxine was detected during the time frame of the study. The minimum levels of each hormone were reached between 12 and 48 hours after cardiopulmonary bypass, indicating that changes in thyroid function and in the conversion of thyroxine to triiodothyronine are triggered by cardiopulmonary bypass and represent specific phenomena, and that these changes are progressively exacerbated during the post-operative period. The thyroid-stimulating hormone level was markedly reduced versus its baseline values (24% +/- 0.13%), despite low levels of both total (40% +/- 18%) and free (39% +/- 20%) triiodothyronine: it returned to its preoperative level by the third postoperative day, but both the total (75% +/- 10%) and free (74% +/- 3%) triiodothyronine levels remained below their baseline values for 7 days postoperatively. Neither hemodilution nor hypothermia was responsible for the alteration observed. We conclude that pediatric patients undergoing cardiopulmonary bypass manifest changes in hormone metabolism similar to those seen in adult patients. These changes increase progressively during the postoperative period, and are still present 7 days postoperatively. The exact mechanism responsible for causing these changes is not thoroughly understood. Whether triiodothyronine replacement therapy is beneficial or deleterious remains controversial.

The potential and limitations of plasma BNP measurement in the diagnosis, prognosis, and management of children with heart failure due to congenital cardiac disease: an update

The aim of this article is to review the diagnostic and prognostic relevance of measurement of brain natriuretic peptide (BNP) and N-terminal pro-brain natriuretic peptide (NT-proBNP) in pediatric patients with heart failure caused by various acquired and congenital heart diseases (CHD). In January 2013, we performed a computerized literature search in the National Library of Medicine (PubMed access to MEDLINE citations; http://www.ncbi.nlm.nih.gov/PubMed/). The search strategy included a mix of Medical Subject Headings and free-text terms for the key concepts, starting from BNP assay and ‘NT-proBNP assay’, children, CHD. The search was further refined by adding the keywords neonate/s, newborn/s, heart failure, cardiomyopathy, screening, prognosis, follow-up, and management. BNP values are age and method dependent, even in pediatric populations. Regardless of age, there is great variability in BNP/NT-proBNP values within CHD characterized by different hemodynamic and clinical conditions. There is enough evidence to support the use of BNP/NT-proBNP as an adjunctive marker in the integrated evaluation of patients with congenital and acquired heart disease to help define severity and progression of heart failure as well in the monitoring of response to treatment. BNP/NT-proBNP can also be used for the screening of heart failure and as a prognostic marker in children undergoing cardiac surgery; however, to date, there are studies with heterogeneous patient groups, and diverse outcome measures selected are still few. BNP/NT-proBNP can be used as adjunctive markers in the integrated screening, diagnosis, management, and follow-up of children with heart failure caused by various acquired and congenital heart disease.

Postoperative outcome in patients with anomalous origin of one pulmonary artery branch from the aorta

OBJECTIVES The aim was to review our experience with the surgical repair of the anomalous origin of one pulmonary branch from the aorta (AOPA). MATERIALS AND METHOD Between January 1991 and March 2002, eight patients with AOPA underwent surgical correction. Three patients presented isolated AOPA. Five patients presented right AOPA and three, left AOPA. Implantation of the AOPA to the main pulmonary artery was performed by: (I) direct anastomosis in two patients with left AOPA; (II) interposition of a synthetic graft in one patient with left AOPA; (III) employing an autologous pericardial patch in two patients with right AOPA; (IV) using an aortic flap in three other patients with right AOPA. The mean follow-up time was 37.7 months. RESULTS One patient died postoperatively due to progressive heart failure unresponsive to inotropic support. Early postoperative pulmonary hypertension crisis was identified in another patient. Within 1 year after surgery, the mean residual gradient across the anastomotic site at follow-up was 14+/-8 mmHg. The patient undergoing interposition of a synthetic graft presented a residual gradient of 29 mmHg and underwent reoperation at almost 2.5 years after the first correction. The residual gradient in patients undergoing correction according to technique I was 17+/-3 mmHg, and in patients undergoing implantation of the AOPA according to techniques III or IV was 9.5+/-4.6 mmHg (P=0.11). Similarly, the Tc-99m scintigraphy demonstrated that a lower lung perfusion (the lung perfused from the respective AOPA compared with the contralateral lung) in patients undergoing AOPA implantation according to technique I was 59+/-6(%) and in patients undergoing techniques III or IV was 72+/-4.5(%) (P=0.038). At follow-up, all patients were alive. CONCLUSION The AOPA from the aorta is a rare but important entity, necessitating a scrupulous preoperative and intraoperative evaluation. Patients presenting this anomaly may undergo correction using various surgical techniques with acceptable results. The techniques employing autologous tissues for enlarging and lengthening the AOPA seems to be associated with less restenosis at the anastomotic site, however, larger series of patients are required to confirm such outcome.

Diagnostic, prognostic and therapeutic relevance of B-type natriuretic hormone and related peptides in children with congenital heart diseases

Abstract The aim of this article is to review the diagnostic and prognostic relevance of measurement of brain natriuretic peptide (BNP) and N-terminal pro-brain natriuretic peptide (NT-proBNP) in pediatric patients with congenital cardiac diseases (CHD). A computerized literature search in the National Library of Medicine using the keywords “BNP assay” and “NT-proBNP assay”+neonate/s and newborn/s was performed. Next, we refined the analysis to include only the studies specifically designed to evaluate the clinical usefulness of BNP and NT-proBNP measurements in children with CHD. Several authors suggested that BNP/NT-proBNP is clinically helpful as a diagnostic and prognostic marker for children with suspected CHD. BNP values are age dependent, even in paediatric populations. Unfortunately, accurate reference values for BNP and NT-proBNP for neonatal ages have only recently become available. As a result, the lack of homogenous and accurate decisional levels in the neonatal period greatly limits the clinical impact of the BNP assay, and also contributed to the production of conflicting results. Regardless of age, there is great variability in BNP/NT-proBNP values among CHD characterized by different hemodynamic and clinical conditions. In particular, cardiac defects characterized by left ventricular volume and pressure overload usually show a higher BNP response than CHD which is characterized by right ventricular volume or pressure overload. BNP and NT-proBNP may be considered helpful markers in the integral clinical approach for patients with CHD. Measurement of BNP cannot replace cardiac imaging (including echocardiography, angiography and magnetic resonance), but provide independent, low cost and complementary information for the evaluation of cardiac function and clinical status.

A possible cardioprotective effect of heat shock proteins during cardiac surgery in pediatric patients.

BACKGROUND Overexpression of heat shock proteins (Hsps) is associated to myocardial protection and it has been suggested that they could be a marker of cardiac preservation in conditions such as extracorporeal circulation. Aim of this study was to evaluate if cardioplegic arrest can modify the expression of Hsps in the heart and if this alteration is associated to cardiac preservation. METHOD The levels of Hsp 27, Hsp 60, and both the constitutive and the inducible form of Hsp 70 were measured in the cardiac tissue from right atrium of pediatric patients before and after aortic cross-clamping (ACC) during cardiopulmonary bypass surgery for correction of congenital heart disease (n=20). The quantitative evaluation of Hsps was made by Western blotting analysis after tissue extraction and protein separation. Hsp 72 mRNA expression was also evaluated in pre- and post-ACC samples of eight subjects by semiquantitative RT-PCR. Peripheral levels of Troponin I, Myoglobin, LDH, CK, CK-MB were measured in basal conditions and at 12 and 24h after cardiosurgery as markers of heart damage. RESULTS The cardioplegic arrest did not significantly modify the mean levels of all the Hsps measured. Hsp 72 levels increased after cardioplegia in the 40% of the patients and all Hsps in the 28% of subjects. The patients whose levels of Hsps are increased after cardioplegia are associated with lower post-surgery concentrations of all the markers of cardiac injury. CONCLUSIONS This observation suggests a relationship between the increase of Hsps and the reduction of cardiac injury.

Reference intervals for brain natriuretic peptide in healthy newborns and infants measured with an automated immunoassay platform

Abstract Background: In order to assess the reference intervals for B-type natriuretic hormone (BNP) in the first days of life, we measured peptide concentrations using the fully automated Access platform. Methods: Plasma BNP was measured in 188 apparently healthy newborns and infants throughout the first month of extra-uterine life, as well as in 245 healthy infants ranging from 1 month to 12 years of age. Results: BNP showed the highest concentrations in the first 2 days of life, with a progressive decline afterwards. Moreover, BNP values in the first week of life were significantly higher (p<0.0001) than values observed in the next periods. As a result, a significant negative correlation was found between BNP and age values when considering all 433 samples (ρ=–0.816, p<0.0001 by the Spearman rank correlation test). There was no significant difference between BNP values found in males and females. Conclusions: According to this data, our study indicates that at least two reference intervals should be used for newborns and infants. The first, with higher BNP values for neonates in the first week of extra-uterine life, and the other, with lower BNP values for infants aged 2 weeks to 12 years. Clin Chem Lab Med 2010;48:697–700.

Surgical closure of muscular ventricular septal defects using double umbrella devices (intraoperative VSD device closure)

OBJECTIVES Surgical closure of some muscular ventricular septal defects has been proven to be difficult. In order to simplify the surgical technique we have used intraoperatively Rashkind double umbrella devices to occlude muscular ventricular septal defects. METHODS On the basis of haemodynamic and echocardiographic study five children aged 4, 6, 7, 14 and 41 months were considered suitable candidates for intraoperative closure of muscular ventricular septal defects (midmuscular in three cases, apical in two) by Rashkind devices. Three of them had previously undergone pulmonary artery banding at 10, 11 and 41 days, respectively. During hypothermic cardiopulmonary by pass a delivery system was introduced across the tricuspid valve into the right ventricle and then passed through the ventricular septal defect; the distal umbrella of a 17 mm device was opened in the left ventricular cavity; a traction was applied to the introducer and the proximal umbrella was opened on the right side straddling the interventricular septum; the device was then secured on the right side by few stitches. In one case because of the wide diameter of the ventricular septal defect two umbrellas were used. The surgical procedure was completed with debanding and/or closure of other defects close to the aortic or tricuspid valve. RESULTS Immediate results, tested by epicardial or transesofageal echo, showed a minimal residual shunt in 4 patients and a moderate shunt in one. No early deaths occurred. A complete atrioventricular block developed in 1 patient who had an additional perimembranous defect closed with a prosthetic patch: a permanent pace maker was inserted 3 months after the operation. There was a late death for untractable right ventricular failure in 1 patient who had a large residual shunt erroneously considered moderate. In this patient, the size of the defect was underestimated both preoperatively then intraoperatively. The four survivors are doing well with no signs of hemodynamically significant residual shunts. CONCLUSIONS The use of Rashkind umbrella devices for closing intraoperatively muscular defects can be helpful to standard surgical techniques when technical problems make patch closure difficult. Its use avoid the need of left ventriculotomy. Careful definition of the size of the defect is mandatory to select suitable candidates.

Review and status report of pediatric left ventricular systolic strain and strain rate nomograms

Abstract Interest in strain (ε) and strain rate (SR) for the assessment of pediatric left ventricular (LV) myocardial function has increased. However, the strengths and limitations of published pediatric nomograms have not been critically evaluated. A literature search was conducted accessing the National Library of Medicine using the keywords myocardial velocity, strain, strain rate, pediatric, reference values, and nomograms. Adding the following keywords, the results were further refined: neonates, infants, adolescents, range/intervals, and speckle tracking. Ten published studies evaluating myocardial velocities, ε, or SR nomograms were analyzed. Sample sizes were limited in most of these studies, particularly in terms of neonates. Heterogeneous methods—tissue Doppler imaging, two- and three-dimensional speckle tracking—were used to perform and normalize measurements. Although most studies adjusted measurements for age, classification by specific age subgroups varied. Few studies addressed the relationships of ε and SR measurements to body size and heart rate. Data have been generally expressed by mean values and standard deviations; Z scores and percentiles that are commonly employed for pediatric echocardiographic quantification have been never used. Reference values for ε and SR were found to be reproducible in older children; however, they varied significantly in neonates and infants. Pediatric nomograms for LV ε and SR are limited by (a) small sample sizes, (b) inconsistent methodology used for derivation and normalization, and (c) scarcity of neonatal data. Some of the studies demonstrate reproducible patterns for systolic deformation in older children. There is need for comprehensive nomograms of myocardial ε and SR involving a large population of normal children obtained using standardized methodology.

Anomalous origin of the left pulmonary artery from the aorta. Our experience and literature review

Abstract Three patients with anomalous origin of the left pulmonary artery (AOLPA) from the aorta underwent surgical correction. Two patients presented with an isolated malformation and one with an associated ventricular septal defect. One of the patients with an isolated malformation presented with an AOLPA from the descending thoracic aorta. Implantation of the AOLPA to the main PA trunk was performed by direct anatomosis in two patients and by interposition of a synthetic graft in the other patient with AOLPA from the descending aorta. All patients survived the operation. Low cardiac output was identified in one patient. The mean residual gradient through the anastomotic site was 21 mmHg at follow-up. We found almost 72 cases with AOLPA reported in the literature with a high mortality rate in patients not undergoing surgery. The most frequently found associated malformation is tetralogy of Fallot and ventricular septal defect. AOLPA from the aorta is a rare but important entity, necessitating a scrupulous preoperative and intraoperative evaluation. Patients with AOLPA can undergo surgical repair with excellent results.