Numerical validation of a new method to assess aortic pulse wave velocity from a single recording of a brachial artery waveform with an occluding cuff.

Recently a new method has been proposed as a tool to measure arterial pulse wave velocity (PWV), a measure of the stiffness of the large arteries and an emerging parameter used as indicator of clinical cardiovascular risk. The method is based on measurement of brachial blood pressure during supra-systolic pressure inflation of a simple brachial cuff [the device is known as the Arteriograph (Tensiomed, Budapest, Hungary)]. This occlusion yields pronounced first and secondary peaks in the pressure waveform, the latter ascribed to a reflection from the aortic bifurcation, and PWV is calculated as the ratio of twice the jugulum-symphysis distance and the time difference between the two peaks. To test the validity of this working principle, we used a numerical model of the arterial tree to simulate pressures and flows in the normal configuration, and in a configuration with an occluded brachial artery. A pronounced secondary peak was indeed found in the brachial pressure signal of the occluded model, but its timing was only related to brachial stiffness and not to aortic stiffness. We also compared PWV's calculated with three different methods: PWVATG (approximately Arteriograph principle), PWVcar-fem (approximately carotid-femoral PWV, the current clinical gold standard method), and PWVtheor (approximately Bramwell-Hill equation). Both PWVATG (R2=0.94) and PWVcar-fem (R2=0.95) correlated well with PWVtheor, but their numerical values were lower (by 2.17+/-0.42 and 1.08+/-0.70 m/s for PWVATG and PWVcar-fem, respectively). In conclusion, our simulations question the working principle of the Arteriograph. Our data indicate that the method picks up wave reflection phenomena confined to the brachial artery, and derived values of PWV rather reflect the stiffness of the brachial arteries.

Changes in perceived health of children with congenital heart disease after attending a special sports camp.

Sports camps for children with cardiac anomalies have existed for many years. However, no formal evaluation of the benefits of attending such camps has been undertaken heretofore. We assessed potential changes in the self-perceived health of children with congenital heart disease who attended a special sports camp. Thirty-one children with cardiac anomalies attended a 3-day multisports camp. Sixteen children, all of whom were 10 years or older, literate, and Dutch- or French-speaking, completed the Child Health Questionnaire (CHQ-CF87) before and after attending the camp. The scores of the children were compared with those of healthy peers by calculating mean standardized differences. After attendance at the sports camp, the children achieved significant improvements in the self-perception of their physical functioning, role functioning due to emotional problems, role functioning due to behavioral problems, mental health, and general behavior. The children's self-esteem and general behavior after the camp were significantly better than that of their healthy counterparts. We conclude that children with congenital heart disease who participate in activities at special sports camps may reap benefits in terms of their subjective health status. Although further research is needed, we recommend the participation in sport activities by children with heart defects, and more specifically their participation in sports camps.

Closure of atrial septal defects: is there still a place for surgery?

BACKGROUND: The purpose of this study is to assess the current management of atrial septal defect closure in an era of increasing feasibility of transcatheter device occlusion. METHODS: Atrial septal defect (ASD) closure was performed surgically through complete sternotomy in 165 patients (group 1) and through partial inferior sternotomy in 53 patients (group 2). Transcatheter device occlusion was achieved in 82 patients with only ASD type II and patent foramen ovale (group 3). RESULTS: Overall complications were minor and more frequent in group 1: 26.7% versus 13.2% in group 2 and 14.6% in group 3 (p = 0.04). Compared to complete sternotomy, a partial sternotomy led to less chest tube loss (7.1 +/- 2.9 versus 11.6 +/- 14.5 ml/kg) (p < 0.05) and less postoperative pericardial effusion (11.3% versus 13.5%)(p = 0.55). ASD closure was effective in 99.4% in group 1, 100% in group 2 but only in 86.6% in group 3 (p < 0.05). Two major complications of device implantation required early surgery: 1 femoral arteriovenous fistula and 1 device embolization. Hospital stay was significantly shorter in group 3, as well as in group 2 compared to group 1 (8.3 +/- 4.2 versus 5.9 +/- 1.1 versus 2.1 +/- 7.3 days) (p < 0.05). Midterm results were excellent, with only 1 non-cardiac death and 1 re-operation for residual shunt in group 1, and 1 device removal for thrombosis in group 3. CONCLUSION: Transcatheter device occlusion has become an established treatment for ASD closure, achieving optimal results in older children and adults with anatomically suited ASD type II and PFO. However, a partial inferior sternotomy offers a valuable and complementary operative approach for all ASD variants, maintaining the predictable success of surgery, with the obvious advantages of minimal access in terms of morbidity, cosmetics and hospital stay.

Is morbidity influenced by staging in the fontan palliation? A single center review.

In a retrospective study of 32 consecutive patients undergoing a total cavopulmonary connection (TCPC), we tried to determine if the trend for decreasing age at Fontan completion and reducing the intervals between the staged procedures during the past decade was associated with a change in morbidity and outcome. In 8 patients the Fontan circulation was completed in one stage and in 24 patients an intermediate step by hemi-Fontan or bidirectional cavopulmonary anastomosis was performed before Fontan completion. Mean age at TCPC and mean interval since the previous palliation have decreased significantly during the past decade. Although major complications were significantly reduced over time the occurrence and duration of postoperative pleural effusions were not. Decreasing age as well as intervals in staged Fontan palliation have beneficial influence on major complications and outcome, without significantly affecting the duration of pleural effusions at Fontan completion.

Percutaneous closure by a vascular plug of a fistula between the superior caval vein and the left atrium.

We report the case of a 7-year-old boy with a history of pulmonary atresia and intact septum who developed a fistula between the remnant of the ligated superior caval vein and the left atrium after bidirectional superior cavopulmonary (Glenn) anastomosis. The close proximity to the right pulmonary veins made closure by a standard occluder impossible. An Amplatzer vascular plug without rim enabled us to close the connection percutaneously without obstructing the pulmonary venous flow. The technique appeared to be easy, safe, and effective.

Long term outcome up to 30 years after the Mustard or Senning operation: a nationwide multicentre study in Belgium.

OBJECTIVE: To assess long term outcome of patients who underwent Mustard or Senning repair for transposition of the great arteries up to 30 years earlier. DESIGN: Retrospective review of medical records. SETTING: The six university hospitals in Belgium with paediatric cardiology departments. PATIENTS: 339 patients were reviewed, of whom 124 underwent the Mustard procedure and 215 the Senning procedure. This represents almost the entire population of patients in Belgium with either simple or complex transposition. MAIN OUTCOME MEASURES: Mortality, morbidity, functional abilities, social integration. RESULTS: Overall mortality was 24.2%. Early mortality (< or = 30 days after surgery) accounted for 16.5%, late mortality for 7.7%. Actuarial survival of early survivors at 10, 20, and 30 years after surgery was 91.7%, 88.6%, and 79.3%, respectively. Patients in the Senning cohort had a slightly better survival rate than those in the Mustard cohort (NS). Baffle obstruction occurred more often after Mustard repair (15.3%) than after the Senning procedure (1.4%). Arrhythmia-free survival did not differ between the two cohorts, but was determined by the complexity of the transposition. Survivors of the Senning cohort had better functional status, and tended to engage in more sports activities. CONCLUSIONS: The long term outcome for patients surviving the Mustard or Senning operation was favourable in terms of late mortality, morbidity, functional, and social status. Overall mortality in the Senning cohort did not differ from the Mustard group, but Senning patients had better functional status, greater participation in sports activities, and fewer baffle related problems.

The midwall stress-velocity relationship during manipulation of afterload.

Despite providing a physiological correction, measurements of contractility using the midwall stress-velocity relationship still show evidence of an unexplained hypercontractile state in some children. We investigated if by using midwall shortening indexes, the known overestimation of contractility at low afterload could be prevented. In 12 piglets (5 or 6 weeks old), afterload was manipulated by balloon occlusion of the descending aorta and infusion of sodium nitroprusside up to 5 mg/kg/min, and left ventricular function was measured using multiple variables. The regression line between the echocardiographically derived midwall velocity of circumferential fiber shortening and end systolic wall stress differed from the regression line of the endocardial stress-velocity relationship. Although the midwall regression line was almost horizontal (or afterload independent) for end systolic wall stress values of more than 30 g/cm2, the slope was still steeper below a certain point of afterload. The increased midwall velocity of fiber shortening at low afterload is comparable to the endocardial stress-velocity relationship and could account for the pseudo-hypercontractile state found in some children.

Remifentanil infusion for cardiac catheterization in children with congenital heart disease.

BACKGROUND: Cardiac catheterization of children with congenital heart disease is increasingly being performed under general anesthesia. Haemodynamic stability during anesthesia and fast and adequate recovery after the procedure is crucial in these patients. We performed a pilot study to evaluate hemodynamic stability when using remifentanil for anesthesia during cardiac catheterization. We also evaluated extubation times and recovery characteristics. METHODS: In a randomized, prospective, double-blind study 30 children (aged 1.5-20 months) received a continuous infusion of either 0.2 (group 0.2) or 0.3 microg/kg/min remifentanil (group 0.3) as part of a balanced anesthesia with 0.6 MAC sevoflurane. Heart rate, noninvasive arterial blood pressure, end tidal CO2 and pulse oxymetry were monitored throughout the procedure. Extubation times were noted, and recovery from anesthesia was evaluated using Aldrete scores. RESULTS: : Haemodynamic response to intubation was well blunted in both groups. No significant changes in hemodynamic variables were noted from induction of anesthesia until 10 min after intubation. From then on there was a decrease in HR and systolic arterial pressure, which remained significant throughout the procedure in both groups. Extubation times were similar in both groups: 7.3 min (2,1) in group 0.2 vs. 6.6 min (2,1) in group 0.3 (NS). The number of patients with an Aldrete score of nine or more was 14 (group 0.2) vs. 15 (group 0.3), 10 min after extubation (NS). CONCLUSION: Both dose regimens of remifentanil provided stable hemodynamic conditions during anesthesia for cardiac catheterization of children with congenital heart disease and allowed for rapid and adequate recovery.

Low-dose dobutamine stress echocardiography in children and young adults.

Dobutamine stress echocardiography has become widely accepted in the evaluation of adult patients with coronary heart disease. We wanted to assess the feasibility and the physiologic responses of stress echocardiography at low doses of dobutamine in a population of normal children and adults. Once achieved, we submitted a group of post-anthracycline patients to the test to assess the sensitivity of low-dose dobutamine stress echocardiography in the detection of cardiac dysfunction. Thirty-two healthy children and young adults (19 male and 13 female subjects, median age 15 years [range 6 to 26]) were studied. After the initial study of normal subjects, we submitted a cohort of 39 patients (18 female and 21 male, aged 6 to 25 years), who completed anthracycline chemotherapy, to the same protocol. Dobutamine was infused at rates of 0.5 to 2.5 and 5 microg/kg/min and echocardiographic measurements were obtained at rest and at the end of each stage. The test could be completed in 100% of the subjects without major complications. Statistically significant differences between resting echocardiographic values of systolic and diastolic function and values at 2.5 and 5 microg/kg/min of dobutamine were found. Moreover, dobutamine revealed or enhanced differences between normal subjects and the post-anthracycline patients. Thus, low-dose dobutamine stress echocardiography is feasible and safe in older children. The test is very sensitive for the detection of subclinical cardiac dysfunction in post-anthracycline patients and could possibly assess functional myocardial reserve.

Plasma amino acid concentrations in term-born infants fed a whey predominant or a whey hydrolysate formula.

BACKGROUND: Hydrolysates are used in the treatment and prevention of cows milk protein allergy. Hydrolysis might alter the plasma level of amino acids. METHODS: Forty-five infants were included in a double-blind prospective study and were randomized in two groups: one receiving a whey predominant formula (n = 20) and the second group receiving a whey hydrolysate formula (n = 25). Weight and length gain was evaluated up to the age of 13 weeks, when blood was sampled for determination of fasting plasma amino acids. RESULTS: Four infants of the hydrolysate group dropped out because refusal to ingest the formula. Weight and length gain at 13 weeks of age were extremely comparable. Significant differences in plasma concentrations were observed for a number of nonessential and essential amino acids (p = .035 to .0001). Threonine and lysine were both higher in the hydrolysate group, and aspartic acid, cystine, methionine, tyrosine, phenylalanine, histidine, and arginine were lower in the hydrolysate group. CONCLUSIONS: These differences in plasma amino acid levels have to be regarded with care because all concentrations were within normal ranges, with the exception of threonine. Weight and length gain of the hydrolysate and the whey predominant formula were identical.

Dobutamine stress echocardiography in the evaluation of late anthracycline cardiotoxicity in childhood cancer survivors.

Late anthracycline cardiotoxicity has been of increasing concern to pediatric oncologists. An increasing number of patients with cardiac dysfunction has been reported without a good correlation between cardiac function or symptoms and routine echocardiographic follow-up. We studied dobutamine stress echocardiography in patients who had received moderate doses of anthracyclines years before. Twenty-three patients (14 male, 9 female; 7-25 y) who completed chemotherapy with moderate doses of anthracyclines (180-380 mg/m2) more than 2 y previously underwent dobutamine stress echocardiography and were compared with a control group of 26 healthy young people (15 male, 11 female; 6-26 y) matched for age and weight. Dobutamine was administered in three periods up to a rate of 5 micro g/kg/min. Eighty-five percent of the patients showed an abnormal response to dobutamine. Both systolic and diastolic functions were affected. The systolic dysfunction was not related to diminished contractility but to an elevated systolic wall stress due to inadequate cardiac muscle thickening. The diminished wall thickening was related to the length of follow-up. Dobutamine proved to be a very sensitive method to detect clinical and subclinical cardiac dysfunction in patients post anthracycline chemotherapy and questions the concept of a safe dose.

Bradycardia and gastroesophageal reflux in term and preterm infants: is there any relation?

Conflicting data are published regarding the influence of acid gastroesophageal reflux on the heart rate. In this study, heart rate was monitored simultaneously with esophageal pH in 50 infants with symptoms suggestive of gastroesophageal reflux disease (frequent vomiting and regurgitations). The data of 25 preterm infants (born at 28-36 6/7 weeks) were compared to those of 25 term infants (born after 37 weeks of gestation). However, both groups were investigated at identical postconceptional age of 47-49 weeks. Not one significant bradycardia (heart rate < or = 80/min during > or = 10 s) was recorded, although 71 "relative bradycardia episodes" (heart rate < or = 80/min during > or = 5 beats) were detected, none lasting for > 5 s. Although the number of infants with relative bradycardia episodes did not differ between groups, the relative bradycardia episodes occurred more frequently in some preterm infants (53 episodes in preterm infants vs. 18 in term babies). Acid gastroesophageal reflux episodes were observed in 46 infants (92%). Neither the number of reflux episodes nor their duration was different in both groups. Simultaneous relative bradycardia episodes and acid reflux episodes were observed in three of 23 preterm and two of 23 term infants (NS). It is concluded that in a population of preterm and term infants with symptoms suggestive of a moderate gastroesophageal reflux pathology, investigated at comparable postconceptional age, most reflux episodes are not time-related to changes in heart rate.

The nutritional value of a whey hydrolysate formula compared with a whey-predominant formula in healthy infants.

Forty-five healthy infants were included in a double-blind randomized prospective study comparing the nutritional value of two formulas. One group received a whey-predominant formula (n = 20); the other group received a whey hydrolysate formula (n = 25). Four infants of the whey hydrolysate group were dropped because they refused the formula. Although the mean daily volume intake was smaller with the whey hydrolysate formula compared with the whey-predominant formula (p < 0.001), the weight gain in the two groups after 13 weeks was identical (27.2 g/day in both groups; the mean difference in weight gain between the groups after 13 weeks was only 8 g). Length gain at 13 weeks was 10.4 cm in the whey-predominant formula group and 10.8 cm in the whey hydrolysate formula group (p = NS). After 13 weeks, blood was sampled for hemoglobin, hematocrit, red blood cell count, white blood cell count, lymphocytes, glycemia, proteins, albumin, prealbumin, calcium, phosphorus, urea, creatinine, iron, iron-binding capacity, zinc, and vitamins A and E. Except for the iron-binding capacity, zinc, urea (in plasma as well as in urine) (all three were higher in the whey hydrolysate group), no significant differences were found. According to these results, exclusive feeding of the whey hydrolysate formula from birth to 3 months of age to healthy infants appears to result in an adequate nutritional status, as assessed at 3 months of age.

A comparative evaluation of whey hydrolysate and whey-predominant formulas. How well do infants accept and tolerate them?

Whey hydrolysate formulas are a recent and important innovation in infant feeding. This study compared clinical tolerance and acceptability of a whey hydrolysate formula (WH) with those of a whey-predominant formula (WF) in 45 infants. Four infants (16%) who refused to drink WH formula were eliminated from the study. Mean volume intake was significantly lower for WH (120 mL/kg/day) than for WF (147 mL/kg/day; P < .001). Consequently, mean caloric intake was also significantly different: 80 kcal/kg/day (WF) vs 97 kcal/kg/day (WF; P < .001). Nevertheless, weight gain from birth to 13 weeks of age was nearly identical in both groups (171% for WH vs 178% for WF). No significant differences were noted in duration of feeding, number of pauses during feeding, number of stools per day, or number of regurgitations per day. The lower rate of caloric intake and the dropout rate of 16% for WH raise questions about the use of WH formula in normal infants, as has become the case in some Western European regions.

The prevalence of Helicobacter pylori-positive serology in asymptomatic children.

Epidemiologic data are presented about the prevalence of Helicobacter pylori positivity as determined by serology in a large series of asymptomatic children (n = 466). Serology is now generally accepted as a valid noninvasive screening method for the detection of Helicobacter pylori infection. Blood samples were taken from 466 apparently healthy children (ages 2-14 years) who were admitted to our pediatric 1-day clinic for elective surgery. The children originated from different ethnic backgrounds. All were born in Belgium and have been living there ever since. Thirty-four (7.3%) had positive titers for Helicobacter pylori. There was a significant increase in the number of positive patients with advancing age (5.4% in the age group 2-8 years and 13.4% in the age group 8-14 years; p < 0.001). We also found a significant difference in the prevalence of Helicobacter pylori positivity between Caucasian Belgian children and non-Caucasian children of different ethnic backgrounds. This relatively high prevalence of positive serology in asymptomatic older children (13.4%) should be considered in studies on the incidence or causative role of Helicobacter pylori in children with chronic abdominal complaints.