Plasma N-terminal pro B-type natriuretic peptide concentrations in dogs with pulmonic stenosis.

The detailed information between plasma N-terminal pro B-type natriuretic peptide (NT-proBNP) concentrations and dogs with pulmonic stenosis (PS) is still unknown. The aim of the present study was to investigate the clinical utility of measuring plasma NT-proBNP concentrations in dogs with PS and to determine whether plasma NT-proBNP concentration could be used to assess disease severity. This retrospective study enrolled 30 client-owned, untreated dogs with PS (asymptomatic [n=23] and symptomatic [n=7]) and 11 healthy laboratory beagles. Results of physical examination, thoracic radiography and echocardiography were recorded. Plasma NT-proBNP concentrations were measured using commercial laboratories. Compared to the healthy control dogs, cardiothoracic ratio was significantly increased in dogs with both asymptomatic and symptomatic PS. Similarly, the ratio of the main pulmonary artery to aorta was significantly decreased in dogs with both asymptomatic and symptomatic PS. The pulmonic pressure gradient in the symptomatic PS dogs was significantly higher than that in the asymptomatic PS dogs. Plasma NT-proBNP concentration was significantly elevated in the symptomatic PS dogs compared to the healthy control dogs and the asymptomatic PS dogs. Furthermore, the Doppler-derived pulmonic pressure gradient was significantly correlated with the plasma NT-proBNP concentration (r=0.78, r(2)=0.61, P<0.0001). Plasma NT-proBNP concentration >764 pmol/l to identify severe PS had a sensitivity of 76.2% and specificity of 81.8%. The plasma NT-proBNP concentration increased by spontaneous PS, i.e. right-sided pressure overload and can be used as an additional method to assess the severity of PS in dogs.

Cardiac troponin I in congenital heart defects with pressure or volume overload.

OBJECTIVE: To evaluate the prevalence of cardiac troponin I (cTnI) and autoantibodies to cTn in children with congenital heart defects with volume or pressure overload fulfilling the criteria for treatment, and in healthy children. DESIGN: The study groups comprised 78 children with volume overload caused by an atrial septal defect or a patent ductus arteriosus, and 60 children with pressure overload caused by coarctation of the aorta or stenosis of the aortic or the pulmonary valve, and 74 healthy controls. Serum levels of natriuretic peptides, cTnI, and autoantibodies to cTn were analyzed at baseline, prior to treatment and in 64 patients 6 months after treatment. RESULTS: At baseline, one child with volume overload, 12 children with pressure overload, and one healthy control had positive cTnI. Further analysis of the pressure overload subgroup revealed that the children with positive cTnI were younger than those with negative cTnI, and had higher levels of natriuretic peptides. The pressure gradient at the coarctation site or stenotic valve was higher in those with positive TnI. Six months after treatment, 63 of 64 children examined were cTnI negative. CONCLUSIONS: The cTnI release is more frequently associated with pressure than volume overload which resolves after treatment in most children.

Cardiac troponin I and C-reactive protein concentrations in dogs with severe pulmonic stenosis before and after balloon valvuloplasty.

OBJECTIVE: To report cardiac troponin I (cTnI) and C-reactive protein (CRP) concentrations in dogs with severe pulmonic stenosis (PS) before and after balloon valvuloplasty (BV). BACKGROUND: Increased morbidity and mortality have been reported with severe PS and histopathologic evidence of myocardial damage is demonstrated with BV. Severity of myocardial injury and inflammation associated with severe PS and BV, as assessed by cTnI and CRP, is unknown. ANIMALS, MATERIALS AND METHODS: Serum cTnI and CRP concentrations were measured in dogs with severe PS (n=23) and following BV (n=16). RESULTS: Baseline cTnI and CRP were elevated in 7/23 (30.4%) and 8/23 (34.8%) dogs. Median cTnI at baseline and post-BV were 0.20 ng/mL(range, 0.20-1.29 ng/mL) and 2.85 ng/mL (range, 0.21-55.40 ng/mL), respectively. Median CRP at baseline and post-BV were 3.40 microg/mL (range, 0-14.70 microg/mL) and 11.70 microg/mL (range, 4.20-120 microg/mL), respectively. Post-BV concentrations were significantly increased compared to baseline for cTnI (p<0.001) and CRP (p=0.001). CONCLUSIONS: Serum cTnI and CRP are increased in dogs with severe PS and following BV. Future studies should evaluate whether biomarkers correlate with severity and prognosis of PS or can be used to guide therapy.

Effects of volume and/or pressure overload secondary to congenital heart disease (tetralogy of fallot or pulmonary stenosis) on right ventricular function using cardiovascular magnetic resonance and B-type natriuretic peptide levels.

The aim of this study was to analyze the effect of pressure and/or volume overload on right ventricular (RV) function and brain natriuretic peptide (BNP) levels in patients with surgically corrected congenital heart disease. Forty-two consecutive patients aged 17 to 57 years (median 30) with congenital heart disease (32 with tetralogy of Fallot and 10 with pulmonary stenosis) were examined. The RV systolic pressure was estimated using Doppler echocardiography. Cardiovascular magnetic resonance imaging was used to obtain the RV volumes, ejection fraction (EF) and corrected EF (cEF). Plasma BNP levels were determined by immunoradiometric assay. Patients were categorized as having volume overload when pulmonary regurgitation was > or =10% and pressure overload when the RV systolic pressure was >40 mm Hg. Patients with RV volume overload had a lower RVEF compared with patients with pressure overload (p = 0.02) and lower left ventricular EF (p <0.001). BNP was higher in patients with volume overload than in patients with pressure overload (p = 0.002). BNP correlated with pulmonary regurgitation, RVEF, RV cEF, and left ventricular EF. In linear regression analysis, RV cEF was an independent predictor for BNP, after adjustment for age. Without the parameter of RV cEF in the regression model, pulmonary regurgitation and RVEF were independently associated with BNP level, after adjustment for age. In conclusion, patients with RV volume overload had higher BNP levels and lower RV function than patients with RV pressure overload. BNP levels were independently associated with the degree of RV volume overload and RV function.

Human leukocyte antigen-DR and ABO mismatch are associated with accelerated homograft valve failure in children: implications for therapeutic interventions.

OBJECTIVE: This study examines the incidence and factors associated with the failure of homograft valves and identifies those factors that are modifiable. METHODS: From 1990 to 2001, 96 homograft valves were implanted in the right ventricular outflow tract of 83 children (mean age 5.1 +/- 5.6 years). Clinical and blinded serial echocardiographic follow-up was performed on all 90 valves in the 77 survivors. RESULTS: Eighteen homograft valves were replaced as the result of pulmonary insufficiency (3), stenosis (9), or both (6). Freedom from reoperation was 71% at 9 years (95% confidence interval, 58%-84%). Forty-eight valves developed progressive pulmonary insufficiency of at least 2 grades, 26 valves developed transvalvular gradients of 50 mm Hg or greater, and 14 of these valves were also insufficient. The freedom from echocardiographic failure (progressive pulmonary insufficiency >or=2 grades or >or=50 mm Hg gradient) was only 27% at 5 years (95% confidence interval, 17%-37%). In a multivariate analysis (Cox regression), use of an aortic homograft (P =.001) and short antibiotic preservation time (P =.04) were associated with reoperation. Younger age (P =.01), ABO mismatch (P =.04), and diagnosis (P =.005) were associated with echocardiographic failure. In the subanalysis of patients with human leukocyte antigen typing, age (P =.002), aortic homograft (P =.04), and human leukocyte antigen-DR mismatch (P =.03) were associated with echocardiographic valve failure. CONCLUSION: Many homografts rapidly become insufficient and require replacement. In our analysis of both reoperation and echocardiographic failure, several immunologic factors are consistently associated with homograft failure. Matching for human leukocyte antigen-DR, blood group, and avoiding short preservation times (thus minimizing antigenicity) offers the potential to extend the life of these valves.

Protein-losing enteropathy after Fontan surgery: resolution after cardiac transplantation.

Protein-losing enteropathy (PLE), defined as severe loss of serum protein into the intestine, occurs in 4% to 13% of patients after the Fontan procedure. We report a case of PLE reversal after heart transplantation in a 14-year-old boy with Fontan circulation who previously was treated unsuccessfully with medical therapy. The protein loss continued after heart transplantation. We administered total parenteral nutrition to rest the bowel. After 16 months, we observed a gradual decrease in protein loss. The patient is doing well 5 years after heart transplantation and had has a normal serum albumin level.

[Successful valvuloplasty of a calcified, high-grade pulmonary valve stenosis with removal of a right-left shunt at the atrial level]. / Erfolgreiche Valvuloplastie einer verkalkten hochgradigen Pulmonalklappenstenose mit Beseitigung eines Rechts-Links-Shunts auf Vorhofebene.

HISTORY AND CLINICAL FINDINGS: A 68-year-old woman, with a cardiac murmur known since childhood and suffering from increasing dyspnoea for several years, was admitted to hospital after echocardiography had suggested pulmonary valve stenosis and an atrial septal defect. While her general condition was satisfactory, she had marked central cyanosis with clubbed fingers and moderate bilateral oedema of the lower legs. A rough, diamond-shaped systolic murmur was heard, loudest over the left 2nd intercostal space. In addition to a cardiac defect with right to left shunt, primary pulmonary disease with cor pulmonale was considered in the differential diagnosis. EXAMINATIONS: Haemoglobin content was 25.1 g/dl, haematocrit 72.4%, red cell count 7.44 x 10(6). Arterial oxygen partial pressure was 40 mm Hg, arterial oxygen saturation 81.8%, Echocardiography further revealed right ventricular enlargement, marked tricuspid regurgitation and a stenosed calcified pulmonary valve. At right heart catheterization a right to left interatrial shunt was calculated at 47% of systemic flow and a systolic pressure gradient between right ventricle and pulmonary artery of 131 mm Hg was measured. TREATMENT AND COURSE: Haemoglobin content was lowered to 19.4 g/dl after bloodletting. Balloon pulmonary valvuloplasty reduced the transvalvular systolic gradient to 31 mm Hg. The further course was without complication: 4 months later the patient had only grade II (NYHA) dyspnoea, the oxygen saturation was 91.3%. CONCLUSION: Severe pulmonary valve stenosis with right to left interatrial shunt can be successfully treated by balloon dilatation even in elderly patients.

Seizures due to lidocaine toxicity in a child during cardiac catheterization.

A 17-month-old boy developed grand mal seizures secondary to lidocaine toxicity during balloon dilatation of a congenital pulmonary valve stenosis. Lidocaine at 38 mg/kg (nine times the recommended maximum dose of 4.5 mg/kg) was administered during a 90-min period in order to optimize local anesthesia. This resulted in toxic serum lidocaine levels (8.7 mg/L; therapeutic range, 1.5-5 mg/L) at the time of seizures. Caution should be exercised with local anesthetics during invasive cardiac catheterizations. Hypercarbia (which lowers the seizure threshold to local anesthetics) should be avoided and the temptation to exceed the maximum recommended dose resisted.

Plasma atrial natriuretic factor concentrations in a canine model of right heart pressure overload.

Two studies were carried out in order to evaluate the plasma atrial natriuretic factor (ANF) concentrations, as well as hemodynamic and renal profiles in a chronic canine model of right heart pressure overload induced by pulmonary artery (PA) banding. In study I (n = 6), the animals were submitted to a gradual increase in pressure to clarify whether an increase in pressure or atrial distension was the main stimulus to ANF secretion. In study II (n = 6), right heart pressure overload was produced more rapidly, resulting in fluid retention and weight gain, thereby completing the model of right heart failure, and allowing an evaluation of the mechanisms involved in ANF resistance. In study I there were significant increases in right atrial pressure over baseline at 20 weeks, ANF levels at 24 weeks and right atrial area at 28 weeks following PA banding. In study II right heart pressures and ANF levels were higher than baseline at 12 weeks (p less than 0.0001), and fluid retention developed between 12-24 weeks in all dogs. The results suggest that increased right heart pressure, rather than atrial size, is a primary stimulus to ANF secretion in chronic right heart pressure overload. Despite the increases in right atrial pressure, clinical fluid retention occurred only with elevations of renin and aldosterone.

Plasma atrial natriuretic peptide in patients with congenital heart diseases.

The plasma level of human alpha-atrial natriuretic peptide was measured in healthy children and patients, 1 month to 15 years of age, with congenital heart diseases. Significant increases were found in patients with a ventricular septal defect, tricuspid valve atresia, patent ductus arteriosus, and atrial septal defect but not in those with pulmonary valve stenosis or tetralogy of Fallot. The levels were significantly higher in children with ventricular septal defects (221 +/- 123 pg/mL) or patent ductus arteriosus (124 +/- 38 pg/mL) than in those with atrial septal defects (65 +/- 42 pg/mL) (P less than .01). The increased levels appeared to be correlated with enlargement of the left atrium (r = .85, P less than .01) but not with the right atrial size or the mean right atrial pressure. They were higher in younger than in older healthy infants, but this age difference did not affect the results. These findings indicate that human alpha-atrial natriuretic peptide is released into the circulation in response to chronic atrial expansion in patients with congenital heart disease and may have an important role in volume homeostasis.

Pulse oximetry and transcutaneous oxygen tension in hypoxemic neonates and infants with bronchopulmonary dysplasia.

The reliability of pulse oximetry and transcutaneous oxygen tension (tcPO2) was investigated in hypoxemic neonates and older infants with chronic hypoxemia due to bronchopulmonary dysplasia (BPD). It was found that during severe hypoxemia (tcPO2 less than 40 mmHg and saturation less than 80%) pulse oximetry showed a better correlation with arterial saturation than tcPO2 with arterial oxygen tension. During mild hypoxemia and normoxemia (tcPO2 40-90 mmHg and saturation 80-95%) tcPO2 and pulse oximetry both showed a good correlation with arterial values. Above 95% saturation and a corresponding tcPO2 of 70-120 mmHg, the correlation between arterial and transcutaneous PO2 was better than that between pulse oximetric and arterial saturation. Computer recording and analysis of tcPO2 and pulse oximetry improves the quality of both noninvasive oxygenation parameters in older infants with BPD.

Investigation of serum bile acids; seven patients with Alagille syndrome.

To clarify whether an abnormal bile acid pattern has a role in the pathogenesis of Alagille syndrome, we compared serum bile acid patterns in seven with Alagille syndrome with those of patients with congenital biliary atresia (CBA), neonatal hepatitis (NH) and normal infants. Of the seven patients with Alagille syndrome, four patients were younger and three were older than 1 year. The mean total serum bile acid level in the infants was higher than in older subjects. There was a dissociation between the levels of serum total bile acid and bilirubin in three of the seven cases. The mean total bile acid levels in serum were in the following decreasing order: CBA, Alagille syndrome, NH and controls. The ratio of cholate to chenodeoxycholate in the younger patients with Alagille syndrome was significantly higher than CBA (P less than 0.001). However, no specific bile acid pattern was found in Alagille syndrome by high-performance liquid chromatography (HPLC).

Open pulmonary valvotomy: report of the first successful open heart surgery at the University College Hospital, Ibadan, Nigeria.

Although cardiac surgery has become the standard procedure for management of intracardiac and extracardiac defects in developed countries, it is still relatively new in Africa. This report describes our first successful open heart surgery on a 16-year-old Nigerian boy who underwent open pulmonary valvotomy under cardiopulmonary bypass for congenital pulmonary stenosis at the University College Hospital, Ibadan, Nigeria, on September 18, 1979.

[Computation of mixed venous oxygen saturation in intracardial shunts and its dependence on age, anesthesia and premedication]. / Die Berechnung der gemischt-venösen Sauerstoffsättigung bei intrakardialen Kurzchlüssen und ihre Abhängigkeit von Alter, Narkose und Prämedikation

In patients with an intracardiac shunt, the oxygen saturation of the mixed venous blood cannot be measured, but it must be estimated from the oxygen saturation in the superior and in the inferior vena cava. We have evaluated the results of patients who had definitively no shunt and who had been catheterized for other reasons. Based on statistical principles we developed formulas to calculate the oxygen saturation of the mixed venous blood. We examined three group of patients: a) Children up to 11 years catheterized during general anaesthesia (58 patients) b) Children up to 11 years catheterized after premedication but without general anaesthesia (53 patients) c) Adults catheterized without general anaesthsia (59 patients) We found that the formulas from the patients who had been catheterized during general anaesthesia were quite different from those without anaesthesia. In the patients without an anaesthesia the superior vena cava was coupled with a much higher factor than the inferior vena cava; in patients with anaesthesia, the contribution of the inferior vena cava was stronger. The age of the patients had no significant influence on our formulas.