The Arterial Switch Operation in Europe for Transposition of the Great Arteries: a Multi-Institutional Study from the European Congenital Heart Surgeons Association

OBJECTIVES: This study analyzes the results of the arterial switch operation for transposition of the great arteries in member institutions of the European Congenital Heart Surgeons Association. METHODS: The records of 613 patients who underwent primary arterial switch operations in each of 19 participating institutions in the period from January 1998 through December 2000 were reviewed retrospectively. RESULTS: A ventricular septal defect was present in 186 (30%) patients. Coronary anatomy was type A in 69% of the patients, and aortic arch pathology was present in 20% of patients with ventricular septal defect. Rashkind septostomy was performed in 75% of the patients, and 69% received prostaglandin. There were 37 hospital deaths (operative mortality, 6%), 13 (3%) for patients with an intact ventricular septum and 24 (13%) for those with a ventricular septal defect (P < .001). In 36% delayed sternal closure was performed, 8% required peritoneal dialysis, and 2% required mechanical circulatory support. Median ventilation time was 58 hours, and intensive care and hospital stay were 6 and 14 days, respectively. Although of various preoperative risk factors the presence of a ventricular septal defect, arch pathology, and coronary anomalies were univariate predictors of operative mortality, only the presence of a ventricular septal defect approached statistical significance (P = .06) on multivariable analysis. Of various operative parameters, aortic crossclamp time and delayed sternal closure were also univariate predictors; however, only the latter was an independent statistically significant predictor of death. CONCLUSIONS: Results of the procedure in European centers are compatible with those in the literature. The presence of a ventricular septal defect is the clinically most important preoperative risk factor for operative death, approaching statistical significance on multivariable analysis.

Methacholine Dose-Response Slopes from Maximal Bronchial Challenge Tests in Asthmatic Children: Methodological Aspects

To determine whether the slope of a maximal bronchial challenge test (in which FEV1 falls by over 50%) could be extrapolated from a standard bronchial challenge test (in which FEV1 falls up to 20%), 14 asthmatic children performed a single maximal bronchial challenge test with methacholin(dose range: 0.097–30.08 umol) by the dosimeter method. Maximal dose-response curves were included according to the following criteria: (1) at least one more dose beyond a FEV1 ù 20%; and (2) a MFEV1 ù 50%. PD20 FEV1 was calculated, and the slopes of the early part of the dose-response curve (standard dose-response slopes) and of the entire curve (maximal dose-response slopes) were calculated by two methods: the two-point slope (DRR) and the least squares method (LSS) in % FEV1 × umol−1. Maximal dose-response slopes were compared with the corresponding standard dose-response slopes by a paired Student’s t test after logarithmic transformation of the data; the goodness of fit of the LSS was also determined. Maximal dose-response slopes were significantly different (p < 0.0001) from those calculated on the early part of the curve: DRR20% (91.2 ± 2.7 FEV1% z umol−1)was 2.88 times higher than DRR50% (31.6 ± 3.4 DFEV1% z umol−1), and the LSS20% (89.1 ± 2.8% FEV1 z umol−1) was 3.10 times higher than LSS 50% (28.8 ± 1.5%FEV1 z umol−1). The goodness of fit of LSS 50% was significant in all cases, whereas LSS 20% failed to be significant in one. These results suggest that maximal dose-response slopes cannot be predicted from the data of standard bronchial challenge tests.

Optimization of fMRI Processing Parameters for Simutaneous Acquisition of EEG/fMRI in Focal Epilepsy

In the context of focal epilepsy, the simultaneous combination of electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) holds a great promise as a technique by which the hemodynamic correlates of interictal spikes detected on scalp EEG can be identified. The fact that traditional EEG recordings have not been able to overcome the difficulty in correlating the ictal clinical symptoms to the onset in particular areas of the lobes, brings the need of mapping with more precision the epileptogenic cortical regions. On the other hand, fMRI suggested localizations more consistent with the ictal clinical manifestations detected. This study was developed in order to improve the knowledge about the way parameters involved in the physical and mathematical data, produced by the EEG/fMRI technique processing, would influence the final results. The evaluation of the accuracy was made by comparing the BOLD results with: the high resolution EEG maps; the malformative lesions detected in the T1 weighted MR images; and the anatomical localizations of the diagnosed symptomatology of each studied patient. The optimization of the set of parameters used, will provide an important contribution to the diagnosis of epileptogenic focuses, in patients included on an epilepsy surgery evaluation program. The results obtained allowed us to conclude that: by associating the BOLD effect with interictal spikes, the epileptogenic areas are mapped to localizations different from those obtained by the EEG maps representing the electrical potential distribution across the scalp (EEG); there is an important and solid bond between the variation of particular parameters (manipulated during the fMRI data processing) and the optimization of the final results, from which smoothing, deleted volumes, HRF (used to convolve with the activation design), and the shape of the Gamma function can be certainly emphasized.