Extracardiac Fontan with T-shape conduit in non-confluent pulmonary arteries

A 34 months-old male patient with double inlet right ventricle with nonconfluent pulmonary arteries who underwent successful extracardiac fenestarated Fontan procedure using pre-designed T-shaped PTFE vascular graft after multi-step rehabilitation of the diminutive hilar pulmonary arteries. At first we performed 6 mm confluent pulmonary artery vascular graft implantation with 4 mm BT shunt at patient's 4 weeks old. At 9 months of patient, we upsized the confluent pulmonary arterial graft to 8 mm with bidirectional cavopulmonary connection, and, at 34 months, we performed extracardiac conduit Fontan procedure with pre-designed T-shape conduit including the confluent pulmonary arterial portion at last. Patient shows excellent functional status and development

Long-Term Results of Cell-Free Biodegradable Scaffolds for In Situ Tissue-Engineering Vasculature: In a Canine Inferior Vena Cava Model

We have developed a new biodegradable scaffold that does not require any cell seeding to create an in-situ tissue-engineering vasculature (iTEV). Animal experiments were conducted to test its characteristics and long-term efficacy. An 8-mm tubular biodegradable scaffold, consisting of polyglycolide knitted fibers and an L-lactide and ε-caprolactone copolymer sponge with outer glycolide and ε-caprolactone copolymer monofilament reinforcement, was implanted into the inferior vena cava (IVC) of 13 canines. All the animals remained alive without any major complications until euthanasia. The utility of the iTEV was evaluated from 1 to 24 months postoperatively. The elastic modulus of the iTEV determined by an intravascular ultrasound imaging system was about 90% of the native IVC after 1 month. Angiography of the iTEV after 2 years showed a well-formed vasculature without marked stenosis or thrombosis with a mean pressure gradient of 0.51±0.19 mmHg. The length of the iTEV at 2 years had increased by 0.48±0.15 cm compared with the length of the original scaffold (2–3 cm). Histological examinations revealed a well-formed vessel-like vasculature without calcification. Biochemical analyses showed no significant differences in the hydroxyproline, elastin, and calcium contents compared with the native IVC. We concluded that the findings shown above provide direct evidence that the new scaffold can be useful for cell-free tissue-engineering of vasculature. The long-term results revealed that the iTEV was of good quality and had adapted its shape to the needs of the living body. Therefore, this scaffold would be applicable for pediatric cardiovascular surgery involving biocompatible materials

Pulmonary Vascular Resistance, Collateral Flow, and Ventricular Function in Patients With a Fontan Circulation at Rest and During Dobutamine Stress

Background-The role, interplay, and relative importance of the multifactorial hemodynamic and myocardial mechanisms causing dysfunction of the Fontan circulation remain incompletely understood. Methods and Results-Using an MRI catheterization technique, we performed a differential analysis of pulmonary vascular resistance and aortopulmonary collateral blood flow in conjunction with global ventricular pump function, myocontractility (end-systolic pressure-volume relation), and diastolic compliance (end-diastolic pressure-volume relation) in 10 patients with a Fontan circulation at rest and during dobutamine stress. Pulmonary and ventricular pressures were measured invasively and synchronized with velocity-encoded MRI-derived pulmonary and aortic blood flows and cine MRI-derived ventricular volumes. Pulmonary vascular resistance and end-systolic and end-diastolic pressure-volume relations were then determined. Aortopulmonary collateral flow was calculated as the difference between aortic and pulmonary flow. Compared to rest, dobutamine caused a small increase in mean pulmonary pressures (P < 0.05). Collateral flow was significantly augmented (P < 0.001) and contributed importantly to an increase in pulmonary flow (P < 0.01). Pulmonary vascular resistance decreased significantly (P < 0.01). Dobutamine did not increase stroke volumes significantly despite slightly enhanced contractility (end-systolic pressure-volume relation). Active early relaxation (tau) was inconspicuous, but the end-diastolic pressure-volume relation shifted upward, indicating reduced compliance. Conclusions-In patients with a Fontan circulation, aortopulmonary collateral flow contributes substantially to enhanced pulmonary flow during stress. Our data indicate that pulmonary vascular response to augmented cardiac output was adequate, but decreased diastolic compliance was identified as an important component of ventricular dysfunction. (Circ Cardiovasc Imaging. 2010;3:623-631.

Modified Nikaidoh procedure for the correction of complex forms of transposition of the great arteries with ventricular septal defect and left ventricular outflow tract obstruction: mid-term results

OBJECTIVES: Different surgical techniques for the treatment of complex transposition of the great arteries (TGA) with ventricular septal defect and left ventricular outflow tract obstruction (LVOTO) have been developed, in particular the Rastelli operation, the réparation à l'étage ventriculaire procedure and the Nikaidoh procedure. The hitherto published results of the Nikaidoh procedure and its modifications compare favourably with those of other techniques; however, experience with the Nikaidoh procedure is still limited. Here, we report our institutions' early and mid-term results with modifications of the Nikaidoh procedure. METHODS: Twenty-one patients who underwent a modified Nikaidoh procedure between 2006 and 2012 at our institution, either as aortic root translocation (n = 17) or as en bloc rotation of the arterial trunk (n = 4), were studied retrospectively. RESULTS: There were 2 early and 1 mid-term deaths. The follow-up continued for a median of 2.3 years (range 0.3-6.4 years). During the follow-up, the performance of the reconstructed left ventricular outflow tract (LVOT) remained excellent: no reobstruction and no aortic valve regurgitation classified as more than mild were observed. Left ventricular function was well preserved. In 4 patients, a significant reoccurring right ventricular outflow tract obstruction due to conduit failure was observed; so far, two reoperations with conduit replacement have been necessary. The mean right ventricular outflow tract peak gradient was 24 ± 7.2 mmHg at the last follow-up in the remaining patients. No reobstruction of the right ventricular outflow tract occurred in patients with preserved pulmonary valve tissue after en bloc rotation. CONCLUSIONS: The aortic translocation procedure is a valuable surgical option for patients with complex (TGA) with ventricular septal defect and LVOTO. The mid-term results document excellent performance of the reconstructed LVOT. Modifications of the Nikaidoh procedure that preserve pulmonary valve tissue may further reduce the need for right ventricular outflow tract reoperation