Sildenafil for the Treatment of Pulmonary Arterial Hypertension in Infants with Bronchopulmonary Dysplasia

Sildenafil, a phosphodiesterase-5 inhibitor, is a controversial treatment option for pulmonary arterial hypertension (PAH), a significant complication of bronchopulmonary dysplasia (BPD). The objective of this study was to evaluate the use of sildenafil in infants with PAH secondary to BPD. This was a retrospective review of medical records of all premature infants with PAH associated with BPD treated with sildenafil between January 2009 and May 2013 in a level 3 neonatal intensive care unit. The primary outcomes were clinical response (20 % decreases in respiratory support score or oxygen requirements) and echocardiographic response (20 % decrease in tricuspid regurgitation gradient or change of at least 1° of septal flattening). Twenty-three infants were included in the study. Significant echocardiographic and clinical responses were, respectively, observed in 71 and 35 % of cases. Most clinical responses were observed in the first 48 h of treatment, and the median time to an echocardiographic response was of 19 days. The median dose of sildenafil used was 4.4 mg/kg/day, with a median time to reach the maximum dose of 9 days. Transient hypotension was the primary reported side effect, and it was observed in 44 % of our study population. Sildenafil treatment in patients with PAH secondary to BPD was associated with an echocardiographic improvement in the majority of patients, whereas clinical improvement was observed in a minority of patients. Many infants presented with transient hypotension during the course of the treatment. Further prospective studies are required to better assess safety and efficacy of this treatment in this population.

[Long QT syndrome in children: analysis of the Lyon series]

Congenital long QT syndrome is a rare and serious disorder in children. In addition to the clinical and electrocardiographical diagnostic criteria, molecular biochemistry has identified six genes which are implicated in this pathology. Our study involved a retrospective analysis of 23 patients aged less than 21 with congenital long QT syndrome, followed up for an average of two years. Genotypes were obtained for all of the patients. There were unfortunately two deaths, one of which had a mutation in the SCN5A gene. The other patient had a double mutation of the SCN5A and KCNE2 genes. Symptomatic patients had QT and QTc intervals noticeably longer than the asymptomatic patients, although this difference was not shown to be significant. LQT3 patients as well as those with a double mutation were affected more severely because two of the three LQT3 patients and one of the two patients with a double mutation suffered a cardiac arrest. Three patients in our study showed no mutation. Nevertheless, two of them suffered a severe cardiac event. This confirms the limits of genetic diagnosis, which could be envisaged in all cases. All of the clinical and ECG data should be combined with the genetic analysis in order to confirm the diagnosis.

Early Intertwin Differences in Myocardial Performance During the Twin-to-Twin Transfusion Syndrome

Background— In the twin-to-twin transfusion syndrome (TTTS), pressure rather than volume overload is increasingly considered as a key factor in the pathogenesis of the cardiomyopathy of the recipient twin. If this is the case, cardiac dysfunction should be among the first signs observed with TTTS. The objective of this study was to determine whether intertwin differences in myocardial function are modified early in the course of TTTS and whether they can help to differentiate this condition from intrauterine growth restriction (IUGR).

Methods and Results— Eight variables were analyzed on the first fetal echocardiography on 21 pairs of twins with TTTS and 11 with IUGR. No difference was found between the 2 groups for the cardiothoracic ratio, pulsatility indices in the umbilical and middle cerebral arteries, and peak velocity of the middle cerebral artery. Significant difference was found for ventricular septal thickness, but with no association with the conditions under study. With TTTS, left ventricular shortening fraction was consistently greater in the donor twins, and myocardial performance indices (MPIs) were elevated in the recipient twins. This increase in MPI was caused by a lengthening of the isovolumic periods compared with those of the donor twin: left ventricular and right ventricular isovolumic periods 0.105±0.047 and 0.097±0.026 seconds, respectively, for the recipient twins versus 0.0561±0.46 and 0.065±0.03 seconds, respectively, for the donor twins ( P <0.001). These changes in the isovolumic periods were mainly due to significant prolongation of isovolumic relaxation times. A change in left ventricular MPI ≥0.09 combined with a change in right ventricular MPI ≥0.05 would identify a TTTS with a sensitivity of 75% and a false-positive rate of 9%.

Conclusions— The observed diastolic function impairment goes along with the pressure-overload pathogenic concept proposed in TTTS. Assessment of intertwin difference in MPI is a valuable tool for early differential diagnosis between TTTS and isolated IUGR.

[Genetics and congenital heart diseases]

We describe in this article the recent data on the genetics of congenital heart defects (CHD) organised by type of CHD although each predisposing genetic factor is associated with a whole variety of CHD types. The recent progress resulting from animal models, molecular cytogenetics and CHD familial cases studies allow a better understanding of the determinism of CHD. This lead in term to improved counselling of parents of affected children and of CHD adults who would like to become parents. Nevertheless, more progress is needed to reach a better accuracy in prediction.

[Dobutamine echocardiography in children after heart transplantation]

Coronary disease of the transplanted heart is the principal cause limiting long-term survival of patients and grafts. In view of the invasive nature of coronary angiography, dobutamine echocardiography has been proposed as a non-invasive diagnostic method for this disease. The aim of this study was to determine the feasibility and reliability of this investigation in transplanted children. Twenty-one echoes were performed with dobutamine infusions in 17 patients transplanted at 10 months to 16.9 years of age (average 8.4 years), and followed up 1.1 to 10.1 years (average 4.4 years): 4 were on antihypertensive drugs but none were treated by betablockers. Dobutamine echocardiography was performed according to the standard protocol used in adults. The maximal level was attained in all cases. No major side effects were observed. The maximal heart rate attained 57 to 89% of the theoretical maximal rate, an increase of 44 to 184% compared with the basal heart rate. The maximal systolic blood pressure rose to 120 to 194 mmHg, an increase of 8 to 109% compared with resting values. The contractility scores and segmental contractile index were normal in 18 cases, abnormal at the maximal level in 2 cases (hypokinesia of segments 8 and 9 and akinesia of segments 10 and 16 with an index of 1.2), abnormal at the lowest levels (hypokinesia of segment 7 with an index of 1.1) and maximal level (hypokinesia of segments 1 and 7 with an index of 1.2) in one case. These results were concordant with coronary angiography performed within 2 to 8 days of echocardiography, and considered as the diagnostic investigation of reference (sensitivity 75%, specificity 100%, positive predictive value 100% and negative predictive value 93%). The authors conclude that dobutamine echocardiography is a non-invasive method easily performed with low risk in transplanted children but its diagnostic performance in coronary disease of the transplanted heart should be confirmed in larger studies.