No abstract

Background-Chronic hypoxia has been shown to modulate nitric oxide (NO) responses in different cell models, but the relationship between hypoxia and NO synthase (NOS) regulation in humans was not studied. We studied the relationship between endothelial and inducible NOS (eNOS and iNOS) activities and expression and chronic hypoxia in children with cyanotic and acyanotic congenital heart defects. Methods and Results-Right atrial tissue was excised from 18 patients during cardiac surgery. eNOS and iNOS activities were measured by conversion of L- [H 3 ]arginine to L-[H 3 ]citrulline. Gene expression of eNOS and iNOS was quantified by competitive reverse transcription-polymerase chain reaction. The eNOS activity and expression were significantly reduced in cyanotic hearts compared with acyanotic hearts: 0.38Ϯ0.14 versus 1.06Ϯ0.11 pmol · mg Ϫ1 · min

Creation or enlargement of ASDs in infants using new nonconventional transcatheter techniques is feasible, safe, and effective, at least in the short-to-mid-term follow-up. Infants with TGA seem to benefit the most because the procedure results in satisfactory clinical stability for subsequent early surgical intervention. In infants with HLHS palliated by a hybrid approach, stent implantation to the atrial septum seems to buy enough time to bring them to the phase II safely despite progressive in-stent obstruction.

The objective of the present study was to determine the relationship between nitric oxide synthases (NOS) and heart failure in cardiac tissue from patients with and without cardiac decompensation. Right atrial tissue was excised from patients with coronary artery disease (CAD) and left ventricular ejection fraction (LVEF) <35% (N = 10), and from patients with CAD and LVEF >60% (N = 10) during cardiac surgery. NOS activity was measured by the conversion of L- [H 3 ]-arginine to L-[H 3 ]-citrulline. Gene expression was quantified by the competitive reverse transcription-polymerase chain reaction. Both endothelial NOS (eNOS) activity and expression were significantly reduced in failing hearts compared to non-failing hearts: 0.36 ± 0.18 vs 1.51 ± 0.31 pmol mg -1 min -1 (P < 0.0001) and 0.37 ± 0.08 vs 0.78 ± 0.09 relative cDNA absorbance at 320 nm (P < 0.0001), respectively. In contrast, inducible NOS (iNOS) activity and expression were significantly higher in failing hearts than in non-failing hearts: 4.00 ± 0.90 vs 1.54 ± 0.65 pmol mg -1 min -1 (P < 0.0001) and 2.19 ± 0.27 vs 1.43 ± 0.13 cDNA absorbance at 320 nm (P < 0.0001), respectively. We conclude that heart failure down-regulates both eNOS activity and expression in cardiac tissue from patients with LVEF <35%. In contrast, iNOS activity and expression are increased in failing hearts and may represent an alternative mechanism for nitric oxide production in heart failure due to ischemic disease.

Initial surgical reconstruction for hypoplastic left heart syndrome (HLHS) is associated with satisfactory outcomes only in a few referral centers. Moreover, there is a persistent high-risk period for sudden death while the patient waits for the next surgical procedure. The development of a less invasive approach, so-called "hybrid," postponing a major surgery outside the neonatal period, might reduce the immediate and late surgical burden on these patients. This is a retrospective study of a contemporary series of patients with HLHS seen in two separate institutions. Patients with HLHS or its variants who underwent a "hybrid" management were included in the study. Data are described as the mean and standard deviation or absolute numbers and percentage, as appropriate. From January 2004 to June 2006, 15 patients (10 male; 5 +/- 3.8 days old and 2.9 +/- 0.5 kg) were included in the study. Ten had both mitral and aortic atresia; the ascending aorta and atrial septal defect measured 2.5 +/- 1.4 and 4.9 +/- 1.2 mm, respectively. There were six hospital survivors after stage I (mortality rate 60%). During the interstage period, all but one patient needed additional procedures. One patient died of bacterial meningitis 4 months after stage I. Four patients were submitted to stage II operation at 6.6 +/- 0.5 months of age and one is waiting for the operation. All four required early reinterventions for pulmonary artery stenosis. Only one was discharged home and was not yet submitted to the third stage. The hybrid approach for HLHS was associated with poor results in this early experience from two independent institutions in a developing country. This might have been related to infrastructure and technical problems, as well as our own learning curve. Institutions working under the same conditions might face similar problems during their initial experience.