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Transplantation of cryopreserved heart valves (allografts) is limited by immune responses, inflammation, subsequent structural deterioration and an expensive infrastructure. In previous studies we demonstrated that conventional frozen cryopreservation (FC) is accompanied by serious alterations of extracellular matrix (ECM) structures. As the main culprit of the observed damages ice crystal formation was identified. Objective of this study was the application principles of cryoprotection as observed in nature, occurring in animals or plants, for ice-free cryopreservation (IFC) of heart valves. Using IFC, valves were processed and stored above the glass transition temperature of the cryoprotectant formulation (-124 degrees C) at -80 degrees C to avoid any ice formation, tissue-glass cracking and preserving ECM. After implantation in the orthotopic pulmonary position in sheep, we demonstrate that IFC resulted in cell free matrices, while maintaining crucial ECM-components such as elastin and collagen, translating into superior hemodynamics. In contrast, we reveal that FC valves showed ECM damage that was not restored in vivo, and T-cell inflammation of the stroma with significant leaflet thickening. Compared to currently applied FC practice IFC also reduced infrastructural needs for preservation, storage and shipping. These results have important implications for clinical valve transplantation including the promise of better long-term function and lower costs.

Background Operative resection is the treatment of choice for native aortic coarctation in most institutions. The ideal timing for elective repair is still a matter of debate. This study evaluated one institution's results with resection and end-to-end anastomosis in the first year of life. Methods Between January 1987 and December 1993, 46 neonates and infants with functionally isolated aortic coarctation underwent operative resection and end-to-end anastomosis. For the patients included in the study, all hospital records, catheterization data, and operative protocols were evaluated for retrospective analysis. To obtain valid follow-up information, all patients were systematically seen on an outpatient basis during 1994. Results After a mean follow-up of 49±24 months (range, 13 to 95 months), recoarctation (arm-leg blood pressure gradient >20mm Hg) occurred in 5 of 26 patients with neonatal operations (19%) and in 1 of 20 patients with operations in infancy (5%, p = not significant). Four of these 6 children with recoarctation needed reintervention. The other 2 patients had only mild recoarctation (gradients of 22 and 30mm Hg, respectively) and were not treated. In all 6 patients, recoarctation was diagnosed within the first 6 months postoperatively. During the whole follow-up period, right arm systolic blood pressures slightly above the 90th percentile of normal developed in 11 of the patients (24%) (7 in the group with neonatal operation and 4 after operation in infancy; p = not significant). Conclusions Resection with end-to-end anastomosis was shown to be an adequate therapeutic strategy for isolated aortic coarctation in neonates and infants. The results indicate that already beyond the neonatal age, there is a relatively low incidence of recoarctation.

Background As young age at modified Fontan operation was thought to be a preoperative risk factor for poorer survival, we studied early and intermediate outcome in our young patient group. Methods Results in children less than 3 years of age (group I; n=26; age range, 7 to 35 months) were compared with those in older patients (group II; n=46; age range, 36 to 219 months). For both groups there was no significant difference with regard to preoperative pathology and hemodynamics. Results With an overall mortality of 9.7% (7/72) there was no significant difference for both groups. Group I (n = 23) and group II (n = 42) survivors did not differ with respect to early postoperative incidence of atrial dysrhythmias, duration and volume of pleural effusion, or incidence of reoperation. Results on intermediate follow-up (group I, 31 ± 14 months; group II, 44 ± 20 months) demonstrated a relatively low incidence of late atrial dysrhythmias (12.3%; 8/65). Late atrioventricular valve insufficiency was significantly more frequent in group I patients. Conclusions With similar preoperative anatomic and hemodynamic parameters including 68% of patients with complex univentricular heart, total cavopulmonary anastomosis could be performed in patients less than 3 years of age with good clinical and hemodynamic results, as achieved in older patients.

With the use of dedicated pediatric single-plane probes, transesophageal echocardiography was performed prospectively in 102 children to determine the potential value of this new technique in the diagnosis (40 patients) and the follow-up of congenital heart disease (29 patients) and as a monitoring technique during the perioperative period or interventional cardiac catheterization (33 patients). The findings were correlated with precordial studies (102 patients), cardiac catheterization (82 patients), epicardial ultrasound findings (18 patients), or surgical inspection (34 patients). The age at investigation ranged from 2.5 months to 14.9 years (mean age, 5.2 years); weight ranged from 3.7 to 52 kg (mean weight, 19.1 kg). Additional information was obtained in 49 patients (48.4%) and was relevant for patient management in 21 patients (20.6%). Major areas of improved diagnostic insight included the following: (1) systemic and pulmonary venous return, (2) atrial morphology, (3) atrioventricular junction abnormalities, (4) left ventricular outflow tract disease, (5) atrial baffle function, and (6) the Fontan circulation. Inherent limitations were as follows: (1) the semiinvasive character of the procedure, (2) the need for heavy sedation or general anesthesia, and (3) the limited imaging planes provided. Transesophageal echocardiography in children can provide important additional diagnostic information on a wide spectrum of congenital heart lesions. The technique would appear to be a highly valuable adjunct to the diagnostic armentarium of the pediatric cardiologist.

In 94 consecutive patients undergoing surgical repair of congenital heart defects the results of intraoperative (after cardiopulmonary bypass) epicardial two-dimensional and Doppler color flow imaging were compared with those of sequential transthoracic echocardiography performed within 24 h of surgery and again before hospital discharge to define the precise role of intraoperative imaging. In 6 of 7 patients with a residual defect requiring immediate surgical revision, intraoperative imaging correctly identified the defect; spectral Doppler imaging underestimated or did not identify a residual outflow tract gradient in 17 patients. Left atrioventricular (AV) valve regurgitation after repair of complete AV septal defect was underestimated in three patients. Although intraoperative documentation of good ventricular function was usually associated with a good outcome, in three patients poor systemic ventricular function after cardiopulmonary bypass was not associated with early mortality. A minor degree of shunting around the patch was a common finding on epicardial and early postoperative imaging and persisted at the time of hospital discharge in 17 of 46 patients who had undergone patch closure of a ventricular septal defect as part of the surgical procedure. Additional trabecular septal defects were missed on color flow imaging after cardiopulmonary bypass in three patients, one of whom required subsequent reoperation. Although intraoperative two-dimensional and color flow imaging permitted the recognition of the majority of residual defects requiring immediate revision, residual outflow obstruction or AV valve regurgitation was usually underestimated.

Previous methods used to assess atrial baffle function after correction of transposition of the great arteries have included precordial echocardiography and cardiac catheterization. To evaluate whether single plane transesophageal echocardiography might provide additional information, its findings were correlated with information derived from both precordial echocardiography and cardiac catheterization in 15 patients (14 Mustard procedures, 1 Senning procedure) aged 4.2 to 33 years (mean 16.3). Precordial ultrasound with combined imaging, color flow mapping and pulsed Doppler ultrasound visualized the supramitral portion of the common systemic venous atrium in every case but could identify only superior limb obstruction in three of six patients, mid-baffle obstruction in zero of two and inferior limb obstruction in zero of two patients. Transesophageal studies with use of the same range of ultrasound methods demonstrated superior limb obstruction (severe in four, mild in two) in six of six patients, mid-baffle obstruction in two of two and inferior limb obstruction in two of two patients. The entire pulmonary venous atrium was equally well interrogated by either ultrasound approach, with both identifying three cases (two mild, one moderate) of mid-pulmonary venous atrium obstruction. However, individual pulmonary vein velocity profiles could only be recorded by transesophageal pulsed Doppler ultrasound. Precordial studies identified baffle leaks (1 large, 2 small) in only three patients, whereas transesophageal studies identified 11 such baffle leaks (1 large, 10 small), which were multiple in two patients. It is concluded that transesophageal echocardiography provides a more detailed and accurate assessment of atrial baffle morphology and function than is provided by either precordial ultrasound or cardiac catheterization. Transesophageal echocardiography appears to be the investigative method that derives the most information and that is applicable on an outpatient basis in adolescent and adult patients.

Following a Mustard's procedure, transoesophageal echocardiography allowed the visualization of all 4 pulmonary veins in 7/12 patients (mean age 14.8 years) and of three veins in a further 2 patients. Both upper pulmonary veins could be visualized consistently. No patient had an isolated pulmonary venous stenosis. In 9 patients in sinus rhythm, computer analysis of Doppler tracings from the left upper pulmonary vein showed significantly lower systolic peak velocities (mean 0.39 +/- 0.10 m/s) and time velocity integrals (mean 6.9 +/- 1.66 cm) than in normal subjects (mean 0.6 +/- 0.09 m/s and 14.4 +/- 2.97 cm respectively; P less than 0.001). We postulate that this is due to compromised atrial relaxation and compliance. In contrast, patients in junctional rhythm (mean 10.7 vs. 7.7 cm in normal subjects). Flow reversal during early ventricular systole (due to tricuspid regurgitation or atrial contraction after retrograde conduction during junctional rhythm) was detected in 6/12 patients. These results confirm that the transoesophageal approach should allow the identification of isolated pulmonary venous obstruction after a Mustard procedure. In addition. detailed analysis of tracings of flow in the pulmonary veins can document the presence of compromised atrial relaxation and help to evaluate the severity of tricuspid regurgitation. It may provide a new index with which to assess impaired systemic ventricular function.