Quantitative morphometric analysis of progressive infundibular obstruction in tetralogy of Fallot. A prospective longitudinal echocardiographic study

Evolving Techniques for the Achievement of Optimal Long-Term Results After Tetralogy of Fallot Repair

Several techniques designed to improve long-term results after repair of tetralogy of Fallot are described. We have recently embarked on a program focused on preserving the native pulmonary valve. Here, combined techniques are described in detail, including intraoperative pulmonary valve balloon dilatation, pulmonary valve reconstruction by delamination and resuspension of the leaflets, and pulmonary valve annulus augmentation. As with any other complex congenital heart disease, senior surgeons should select teaching cases, starting from the less severe side of the spectrum.

Conal septal morphometrics can identify higher risk neonates with tetralogy of Fallot

BACKGROUND

Some neonates with tetralogy of Fallot (TOF) have rapid progression of right ventricular outflow tract obstruction, requiring early repair irrespective of Doppler gradient as measured in the neonatal period. The aim of this study was to test the hypothesis that infundibular morphology in neonates with TOF is associated with the occurrence of hypercyanotic spells and need for neonatal surgery.

METHODS

Fifty patients with TOF undergoing surgical repair from 2003 to 2009 were studied. Neonatal echocardiograms were retrospectively analyzed to measure conal septal angle (the angle between the conal septum and the horizontal plane passing through the center of the aortic valve in the parasternal short-axis view, with a larger angle denoting more anterocephalad deviation of conal septum), conal septal thickness and length, the degree of aortic dextroposition, and sizes and Z scores of the pulmonary annulus and the main and branch pulmonary arteries. Outcomes included the occurrence of hypercyanotic spells and the need for neonatal surgery.

RESULTS

The median age at first echocardiogram was 2 days (range, 0-12 days). The median age at surgery was 94 days (range, 5-282 days); hypercyanotic spells occurred in 17 patients (34%), and nine (18%) underwent neonatal repair. The presence of a wider conal septal angle was significantly associated with the occurrence of hypercyanotic spells (59 ± 21° vs 48 ± 13°, P = .023) and the need for neonatal surgery (67 ± 13° vs 48 ± 16°, P = .004). The positive and negative predictive values of hypercyanotic spells for conal septal angles ≥60° were 64% and 78%, respectively. Importantly, Doppler right ventricular outflow tract gradient at initial echocardiography, degree of aortic dextroposition, and pulmonary or aortic valve size were not associated with these outcomes.

CONCLUSIONS

A wider conal septal angle is associated with the occurrence of hypercyanotic spells and the need for neonatal surgery.

"Tetralogy of Fallot" and Etienne-Louis Arthur Fallot

The eponym "tetralogy of Fallot" did not become a common noun in pediatric cardiology vocabulary for several decades after Etienne-Louis Arthur Fallot's report in a French medical journal. There were others before Fallot who described the abnormal cardiac anatomical findings seen in tetralogy of Fallot, but his name became fixed to the condition's eponym primarily through Maude Abbott popularizing the term.

Molecular and cellular mechanisms of T cell development

The thymus is central to the establishment of a functioning immune system. Here is the place where T cells mature from hematopoietic progenitors, driven by mutual interactions of stromal cells and the developing thymocytes. As a result, different types of T cells are generated, all of which have been carefully selected for the ability to act in host defense towards non-self and against the potential to mount pathogenic self-reactive autoimmune responses. In this review we summarize our present knowledge on the lineage decisions taking place during this development, the selection processes responsible for shaping the T cell antigen-receptor repertoire, the interactions with the stromal components and the signal transduction pathways which transform the interactions with the thymic microenvironment into cellular responses of survival, proliferation, differentiation and, importantly, also of cell death.

Influence of perioperative factors on outcomes in children younger than 18 months after repair of tetralogy of Fallot

BACKGROUND

There has been a trend toward advocating earlier repair of tetralogy of Fallot and avoiding palliative procedures. The impact of this trend on perioperative outcomes has not been adequately documented.

METHODS

Data from consecutive patients undergoing repair of tetralogy of Fallot at less than 18 months of age from May 1987 to September 1994 were reviewed. Independent factors associated with duration of stay in the intensive care unit were sought.

RESULTS

Repair was performed in 89 infants at a median age of 13 months (range, 15 days to 18 months). A systemic-pulmonary artery shunt was present in 24% of patients. Mean duration of cardiopulmonary bypass was 119+/-37 minutes; 63% of patients received a transannular patch. There were six deaths (7%), all occurring less than 48 hours after repair. The median duration of stay in the intensive care unit was 5 days (range, 1 day to 8 months). Significant independent factors associated with increasing length of intensive care unit stay included younger age at repair, previous shunt, malformation syndrome, increased total dose and number of inotropic agents used, and respiratory complications. Hemodynamic variables serially recorded in the first 48 hours after repair were independently associated with death or prolonged (>7 days) duration of stay.

CONCLUSIONS

Although outcomes after repair of tetralogy of Fallot in infants are good, both younger age at repair and previous palliative procedures were associated with longer duration of stay in the intensive care unit.

Prospective echocardiographic analysis of progressive obstruction of the proximal pulmonary artery in congenital heart disease and obstructed pulmonary flow

BACKGROUND

It is uncertain whether proximal pulmonary artery (PA) obstruction exists soon after birth and whether its progress relates directly to postnatal ductal constriction in congenital heart disease and obstructed pulmonary flow.

METHODS

Serial morphometric analyses of the PA branches by echocardiogram were performed in 28 patients (mean age at initial study 2.5 days) until severe constriction of the ductus occurred (mean age 47 days). These patients were divided into 2 groups by subsequent angiographic or postmortem confirmation; 10 with proximal PA obstruction (group 1) and 18 without obstruction (group 2).

RESULTS

At the time of initial examination, the mean indexed diameter of the proximal PA on the side of the ductus arteriosus in group 1 was significantly smaller than that on the contralateral side (5.2+/-0.7 versus 9.0+/-0.7 mm/BSA0.5, P < .001) or that in group 2 (8.0+/-0.4 mm/BSA0.5, P < .001). In group 1, 8 patients had a proximal PA index on the ductal side < or = 5.5 mm/BSA0.5, which was less than those of any group 2 patients. After severe constriction of the ductus, the proximal PA index on the ductal side further decreased only in group 1 (P < .01).

CONCLUSIONS

These data indicate that unilateral obstructive lesion of branch PA is present shortly after birth and its progression relates directly to ductal constriction. Neonates with branch PA obstruction can be identified on their initial echocardiogram as having a proximal PA index on the ductal side < or = 5.5 mm/BSA0.5.