Favorable Effects of Oxygen Inhalation in Patients After Bidirectional Glenn Procedure as Assessed by Cardiovascular Magnetic Resonance Flow Measurement.

BACKGROUND: Home oxygen therapy (HOT) is used to adapt patients to the bidirectional Glenn (BDG) physiology. However, the precise cardiovascular effect of oxygen inhalation is still unknown. We used phase-contrast MRI to evaluate the cardiovascular effects of oxygen inhalation in young patients with BDG physiology. METHODS AND RESULTS: The 56 sessions of cardiac MRI were performed in 36 patients with BDG circulation. Oxygen saturation (SpO2) and heart rate (HR) were monitored under both room air and nasal 100% oxygen inhalation, and the blood flow volumes of the ascending aorta (AA), superior vena cava (SVC), and inferior vena cava (IVC) were measured by phase-contrast MRI. Systemic-to-pulmonary collateral flow (SPCF) volumes were calculated by subtracting the sum of flow volumes through the SVC and IVC from the flow volume through the AA, and used for further comparative examination. Under nasal oxygen inhalation, SpO2significantly increased from 82% to 89%, while HR decreased from 115 to 110 beats/min. AA (5.0 vs. 4.9 L·min(-1)·m(-2)), SVC (1.85 vs. 1.77 L·min(-1)·m(-2)), and systemic blood flow volume (=SVC+IVC) significantly decreased (3.60 vs. 3.46 L·min(-1)·m(-2)). In contrast, SPCF and the pulmonary-to-systemic blood flow ratio (Qp/Qs) remained unchanged. CONCLUSIONS: Oxygen inhalation improved arterial blood oxygenation and lowered HR in patients with BDG circulation without an increase in Qp/Qs. HOT would be protective of the cardiovascular system in patients with BDG circulation. (Circ J 2016; 80: 1378-1385).

Modified Technique to Create Diabolo Stent Configuration.

Diabolo stent configuration aids in stent positioning, stability, and creating a controlled defect with a predetermined size. A number of techniques to create the diabolo configuration have been previously described. The indications for creating a controlled "defect" are rapidly growing and include the Fontan circulation, patients with severe end-stage pulmonary hypertension, restrictive atrial communication in the setting of hypoplastic right or left heart syndrome, and diastolic left heart failure. We describe an alternative technique using a prefabricated readily available tool (gooseneck snare) to create a diabolo stent configuration. The chosen balloon expandable stent is mounted on a 5-mm gooseneck snare centered on an angioplasty catheter larger than 5 mm diameter. When deployed, the snare restricts the central waist to 5 mm and both ends expand to a larger diameter creating a dumbbell/diabolo configuration. A total of six diablo stent configurations were successfully implanted in four patients with failing Fontan physiology; five to create a transcatheter fenestration and one to relieve atrial septal restriction. Data expressed as median and IQR. Their weight was 24.8 kg (19.6-46.95), and age years was 9.2 (6.28-13.23). There were no complications and a consistent diabolo configuration with a 5-mm central waist was created in all patients. The snare serves as a sterile, preconfigured, radiopaque, readily available tool of adequate length and strength, to create consistent diabolo stent configuration without any modifications. This technique is a simple, reproducible, and easy to learn.

Evaluation of cerebral oxygenation and perfusion with conversion from an arterial-to-systemic shunt circulation to the bidirectional Glenn circulation in patients with univentricular cardiac abnormalities.

OBJECTIVE: Superior vena cava pressure after the bidirectional Glenn operation usually is higher than that associated with the preceding shunt-dependent circulation. The aim of the present study was to determine whether the acute elevation in central venous pressure was associated with changes in cerebral oxygenation and perfusion. DESIGN: Single-center prospective, observational cohort study. SETTING: Academic children's hospital. PARTICIPANTS: Infants with single-ventricle lesions and surgically placed systemic-to-pulmonary artery shunts undergoing the bidirectional Glenn operation. INTERVENTIONS: Near-infrared spectroscopy and transcranial Doppler sonography were used to measure regional cerebral oxygen saturation and cerebral blood flow velocity. MEASUREMENTS AND MAIN RESULTS: Mean differences in regional cerebral oxygen saturation and cerebral blood flow velocity before anesthetic induction and shortly before hospital discharge were compared using the F-test in repeated measures analysis of variance. In the 24 infants studied, mean cerebral oxygen saturation increased from 49%±2% to 57%±2% (p = 0.007), mean cerebral blood flow velocity decreased from 57±4 cm/s to 47±4 cm/s (p = 0.026), and peak systolic cerebral blood flow velocity decreased from 111±6 cm/s to 99±6 cm/s (p = 0.046) after the bidirectional Glenn operation. Mean central venous pressure was 8±2 mmHg postinduction of anesthesia and 14±4 mmHg on the first postoperative day and was not associated with a change in cerebral perfusion pressure (p = 0.35). CONCLUSIONS: The bidirectional Glenn operation in infants with a shunt-dependent circulation is associated with an improvement in cerebral oxygenation, and the lower cerebral blood flow velocity is likely a response of intact cerebral autoregulation.

Magnetic resonance imaging-guided surgical design: can we optimise the Fontan operation?

The Fontan procedure, although an imperfect solution for children born with a single functional ventricle, is the only reconstruction at present short of transplantation. The haemodynamics associated with the total cavopulmonary connection, the modern approach to Fontan, are severely altered from the normal biventricular circulation and may contribute to the long-term complications that are frequently noted. Through recent technological advances, spear-headed by advances in medical imaging, it is now possible to virtually model these surgical procedures and evaluate the patient-specific haemodynamics as part of the pre-operative planning process. This is a novel paradigm with the potential to revolutionise the approach to Fontan surgery, help to optimise the haemodynamic results, and improve patient outcomes. This review provides a brief overview of these methods, presents preliminary results of their clinical usage, and offers insights into its potential future directions.

Stent implantation into the interatrial septum in patients with univentricular heart and a secondary restriction of interatrial communication.

BACKGROUND: Presence of a restrictive interatrial communication in patients with univentricular anatomy significantly affects surgical outcomes. In patients with univentricular hearts, wide open atrial communication leads to lower pulmonary artery pressure, which is one of the most important factors influencing the success of bidirectional Glenn and Fontan operations. In some patients, recurrence of restricted interatrial communication can be observed despite initially successful interventional or surgical creation of unrestrictive interatrial communication. AIM: To evaluate efficacy of stent implantation into the interatrial septum in patients with univentricular heart and a secondary restriction of interatrial communication. METHODS: In 2006-2010, we created unrestrictive interatrial communication by stent implantation into the interatrial septum in 7 children with univentricular anatomy with systemic right ventricle (4 patients with hypoplastic left heart syndrome and 3 patients with mitral atresia). In all patients we diagnosed recurrent restriction of interatrial communication despite prior surgical or interventional creation of unrestrictive interatrial communication. Patient age at stent implantation was 3 to 30 months. Maximal systolic pressure gradient between the left and the right atrium was 6-29 mm Hg and left atrial pressure ranged from 20/17/19 mm Hg to 40/29/32 mm Hg. In all patients, we implanted a Palmaz-Genesis stent (length 18-29 mm) with subsequent balloon redilatation. RESULTS: In all 7 patients, we created unrestrictive interatrial communication with mean pressure gradient reduction from 13.14 mm Hg to 0.86 mm Hg (p < 0.006). Mean interatrial communication diameter increased from 4.14 mm to 10.57 mm (p < 0.0001). CONCLUSIONS: Percutaneous stent implantation into the interatrial septum in children with univentricular heart and secondary restriction of interatrial communication is a safe and effective method. Kardiol Pol 2011; 69, 11: 1137-1141.

Fontan "Ten Commandments" revisited and revised.

Choussat's "Ten Commandments," which describes the components of an ideal Fontan candidate, was first published in 1977. Despite the wisdom in these commandments, it is clear from a historic perspective that total compliance with all criteria does not necessarily portend excellent long-term survival. I believe the end point of the original commandments should be modified to include improvement in long-term survival. I suggest the following single commandment: "Thou Shalt Be Perfect."

Use of a fenestration should be routine during the Fontan procedure: PRO.

The physiologic effects of a fenestration are to decrease "Fontan pressure" and systemic oxygen saturation, but to improve both cardiac index and systemic oxygen delivery. Several nonrandomized studies have shown that a fenestration improves clinical outcomes by decreasing the duration of postoperative effusions and the length of hospital stay. The single prospective, randomized study has also shown that use of a fenestration improves clinical outcomes. While there are some disadvantages to a fenestration; these are of relatively limited clinical importance. Selective rather than routine use of a fenestration relies on the ability to predict outcome based on preoperative or intraoperative variables. However, none of these variables has been found to have useful predictive value in the individual patient. In conclusion, the Fontan procedure can be done without a fenestration, with good outcomes. However, the positive effects of a fenestration on duration of effusions and length of hospital stay argue that use of a fenestration should be routine during the Fontan procedure.