Results of complete correction of various forms of transposition of the great vessels in the infant

Over the past 3 years, a Mustard operation has been performed in 38 infants aged 30 days to 24 months, among them 29 less than one year of age. There were 27 TGV with intact ventricular septum, 8 TGV and VSD, (isolated in 3, and associated with PS in 2 and with coarctation of the aorta in 3), 2 TGV with isolated PS, and 1 TGV with aorta-pulmonary window. The operation was carried out under deep hypothermia, circulatory arrest and limited by-pass, using a pericardial patch in all cases but one. The operative mortality is 8% (3 cases) for the whole group, 7% in infants less than one year of age, and 3% for all TGV with intact ventricular septum. The long term results are reviewed, with a follow-up of 2 to 36 months (mean 17 months).     

Surgical correction of failures associated with corrected transposition of the main vessels

The results of a study carried out on 90 subjects exposed to vibratory trauma of the hand-arm compared to a non-risk control group of 54 subjects are reported. All subjects underwent a medical and neurological examination and Doppler ultrasound of the upper limbs, plethysmography of the hands, electromyography of the bilateral median nerve area and T.T.T. (Thermal Threshold Tester) evaluation of the thermal threshold, were performed. Workers exposed to risks show a higher threshold for hot/cold sensitivity compared to those not exposed. This increase is earlier compared to the onset of vascular and neurophysiological changes detected by plethysmography, Doppler ultrasound and electromyography. Thermal threshold evaluation by T.T.T. would seem to be a useful test for monitoring workers exposed to vibrations.     

Complete transposition of great vessels: clinical aspects, diagnosis, echocardiography

The paper reports the study of 12 patients admitted to hospital between January 1992 and October 1994. The patients were almost all neonates. Clinical, electrocardiographic and radiological data led to the suspected diagnosis of complete transposition of the great vessels. 2-D echocardiography consistently showed the parallel disposition of great vessels, the anterior position of the aorta compared to the pulmonary artery, the origin of the pulmonary artery from the left ventricle and the aorta from the right ventricle, all of which are the anatomopathological characteristics of this congenital cardiopathy, together with associated malformations, thus enabling a certain diagnosis to be made. The authors underline the value of echocardiography in the diagnosis of complete transposition of the great vessels.     

Complete correction of transposition of the great arteries with left juxtaposition of the atrial appendages

Juxtaposition of the atrial appendages is an uncommon anomaly which is usually associated with transposition of the great arteries. Experience with five patients with transposition of the great arteries in combination with juxtaposition of the atrial appendages in whom Mustard's operation was performed is reviewed. Technically, the existence of juxtaposition of the atrial appendages in corrective surgery for transposition does not present any additional surgical problems. Emphasis is placed on the advantages of early complete correction, avoiding the need for palliative procedure.     

Correction of complete transposition of great vessels by the Mustard technic (26 cases operated)

Laser Raman spectra of neurotoxins of Pelamis platurus (yellow-bellied sea snake) and Laticauda semifasciata (broad-banded blue sea snake) were investigated. The amide I band appeared at 1672 cm-1 for both toxins, which presents an indication of anti-parallel beta structure. Since this agrees well with the result from the CD-ORD studies of snake neurotoxin, it was concluded that snake neurotoxins mainly consist of beta structure. The amide III band appeared at 1245 cm-1 for P. platurus toxin and 1248 cm-1 for L. semifasciata toxin. The four disulfide bonds present in the toxin have a very similar geometry. After vigorous heat treatment, the backbone configuration of the toxin molecule basically remained the same although it was partially denatured. The major peak at 512 cm-1 was not altered by the heat treatment but a new shoulder appeared at 546 cm-1. This suggests that a new type of S-S stretching vibration (trans-gauche-trans) was produced as a result of heat treatment. However, the majority of the S-S vibrations remained in the gauche-gauche-gauche orientation. A substantial change in the interactions between a tyrosine aromatic ring and neighboring residues was apparently the alteration caused by the heat treatment.     

Myocardial blood flow and coronary flow reserve late after anatomical correction of transposition of the great arteries

OBJECTIVES: Myocardial blood flow (MBF) in children late after arterial switch operation (ASO) was investigated quantitatively by positron emission tomography (PET). BACKGROUND: In children with transposition of the great arteries (TGA), ASO is widely accepted as the management of choice. The long-term patency of coronary arteries after surgical transfer to the neo-aorta, however, remains a concern. METHODS: Twenty-two normally developed, symptom-free children were investigated by PET with nitrogen-13 ammonia at rest and during adenosine vasodilation 10+/-1 years after ASO. A subgroup of 15 children (9+/-1 years; group A) had simple TGA and underwent ASO within 20 days after birth while 7 (13+/-3 years; group B) had complex TGA and underwent ASO and correction of associated anomalies later after birth. Ten young, healthy adults (26+/-6 years) served as the control group. RESULTS: Resting MBF was not different between groups. After correction for the rate-pressure product as an index of cardiac work, younger children of group A had significantly higher MBF at rest compared to healthy adults (102+/-29 vs. 77+/-6 ml/100 g/min; p = 0.012) while flow in group B was not different from the other groups (85+/-22 ml/100 g/min; p = NS). Hyperemic blood flows were significantly lower in both groups after ASO compared to normals (290+/-42 ml/100 g/min for group A, 240+/-28 for group B, 340+/-57 for normals; p < 0.01); thus, coronary flow reserve was significantly lower in both groups after ASO compared to healthy adults (3.0+/-0.6 for group A, 2.9+/-0.6 for group B, 4.6+/-0.9 for normals; p < 0.01). CONCLUSIONS: Blood flow measurements suggest decreased coronary reserve in the absence of ischemic symptoms in children late after arterial switch repair of TGA. The global impairment of stress flow dynamics may indicate altered vasoreactivity; however, the prognostic significance of these findings needs to be determined.     

Penetrating injuries involving the intrathoracic great vessels

Approximately 50% of the forearm vasodilatation to intra-arterial infusions of acetylcholine is mediated by endothelium-derived nitric oxide. These conclusions have been derived from venous occlusion plethysmographic measurements of total forearm blood flow during co-infusions of acetylcholine and NG-monomethyl-L-arginine (L-NMMA), an inhibitor of nitric oxide synthase. Since venous occlusion plethysmography measures total limb blood flow, the relative proportion of the measurement from skin cannot be determined precisely. To determine the effects of acetylcholine on skin specifically, we have used laser Doppler flowmetry to measure vascular responses to local iontophoresis of acetylcholine in the forearm of normal male volunteers. To elucidate the possible mechanisms of cutaneous vasodilatation to acetylcholine, vascular responses were measured before and after systemic inhibition of prostanoid production and nitric oxide synthesis by oral aspirin (600 mg daily for 3 days) and intravenous L-NMMA (3 mg/kg for 60 min), respectively. After aspirin administration, dose-dependent vascular responses to acetylcholine were reduced significantly by approximately 53% (p < 0.005, ANOVA). In contrast, intravenous L-NMMA appeared to have no significant effect on cutaneous vascular responses to acetylcholine. While the role of nitric oxide is uncertain, vasodilatation to acetylcholine in the forearm skin is mediated largely by a prostanoid-dependent mechanism. Assessment of cutaneous vascular responses to iontophoresis of acetylcholine may, therefore, be useful in diseases where abnormal endothelium-dependent prostanoid function has been implicated.     

Haemodynamics after Mustard's operation for transposition of the great arteries

Cardiac catheterization data from 54 investigations after Mustard's procedure were examined to study the influence of the operation on pressure events in the atria, great veins, and pulmonary circulation. Systemic venous atrial pressure tracings were characterized by a rapid, sharp 'y' descent. Pressure gradients between the venae cavae and systemic venous atrium were invariable, whether or not vena caval pathway obstruction was present, the 'y' trough and 'a' wave gradients being greater than the mean gradient. Pulmonary venous atrial pressure tracings were not different from normal except when tricuspid regurgitation was present. It is suggested that the baffle effectively reduces the size and compliance of the systemic venous atrium, but influences the pulmonary venous atrium to a lesser degree. The systolic pressure gradient from the left ventricle to pulmonary artery was decreased postoperatively, suggesting that it may be flow-related; the greatest changes were seen in the group with preoperative ventricular septal defect. The ratio of pulmonary: systemic vascular resistance did not change significantly after operation, and it is suggested that both the pre- and postoperative values were higher than normal. Examination of the left ventricular or pulmonary arterial mean pressure postoperatively should raise the suspicion of a complication, e.g. pulmonary venous obstruction or tricuspid regurgitation.     

Left anterior and left posterior hemiblock in tricuspid atresia and transposition of the great vessels: observations and electrocardiographic nomenclature and electrophysiologic mechanisms

A patient with tricuspid atresia and characteristic electrocardiographic features of counterclockwise and superiorly oriented frontal plane QRS loop (left anterior hemiblock) is presented. Operative intervention resulted in a clockwise and inferior rotation of the frontal QRS loop (left posterior hemiblock) without the development of complete left bundle branch block. This observation suggests that the electrocardiographic pattern of left anterior hemiblock may result from other mechanisms in addition to block of the left bundle branch fibers oriented toward the anterior part of the left ventricle. The case further suggests that electrocardiographic patterns of apparent A-V conduction defects may not be at all associated with true block in the A-V conduction system. Further, it emphasizes the fact that various electrophysiologic mechanisms may account for identical electrocardiographic patterns.     

Congenitally corrected transposition of the great arteries and exercise-induced ventricular tachycardia

Congenitally corrected transposition of the great arteries (CCTGA) is an uncommon condition. Few patients survive past 50 years of age, because of associated congenital defects, systemic (morphological right) ventricular dysfunction, atrioventricular valvular insufficiency or complete heart block. A unique case is presented of exercise-induced ventricular tachycardia, which led to the diagnosis of CCTGA, without atrioventricular block or other cardiac anomalies.     

Plain-film assessment of the neonate with D-transposition of the great vessels

The presenting chest radiographs of 27 new-born patients with D-transposition of the great vessels (D-TGV) were evaluated for the degree of pulmonary flow as well as other findings classically described in D-TGV (narrow superior mediastinum, radiographically absent thymus, inapparent main pulmonary artery, non-visualization of the malpositioned aortic arch, asymmetric pulmonary blood flow, and cardiomegaly). Of the 27 patients, 22 (82%) demonstrated normal or decreased flow. The majority of the D-TGV patients also failed to demonstrate any of the other classically described radiographic findings. A normal chest radiograph is the most common presenting scenario in the neonate with D-TGV.