Bilateral bidirectional cavopulmonary connection: a review of surgical techniques and clinical implications.

The presence of bilateral superior caval veins (bSCVs) could negatively influence the outcome of Fontan patients. In the setting of a bilateral bidirectional Glenn, the selective blood flow to the ipsilateral long with consequent flow stagnation in the connecting portion could lead to poor growth of the central portion of the pulmonary artery, potentially affecting the eligibility for Fontan completion and being associated with a higher incidence of thrombotic complications. Alternative surgical techniques have been described to perform a bidirectional cavopulmonary anastomosis in the presence of bSCVs aiming to achieve a balanced growth of the pulmonary bifurcation. The short-term results of these techniques such as the V- or Y-shape seem to be excellent; however, some anatomical settings could affect the feasibility of these techniques. The so-called "unifocalization" creates a configuration comparable to a "normal" bidirectional Glenn and could be a feasible alternative. However, the long-term results of this technique are not published yet. The positive effect of additional pulsatile pulmonary flow on pulmonary artery growth should be considered in case of bilateral bidirectional Glenn, despite the higher incidence of postoperative complications reported and the difficult calibration of the amount of additional flow. The role of computational fluid dynamic to simulate the surgical strategy in single ventricle patients is promising and could be worthwhile in the setting of bSCVs. In fact, the surgical techniques of bilateral bidirectional Glenn could be simulated testing their feasibility and allowing to identify the more favorable hemodynamic pattern, patient specific. This review article highlights the critical issues related to the presence of bSCVs in univentricular physiology, analyzing pros and cons of the different surgical techniques. Besides reviewing the literature, this manuscript focuses on the role of computational fluid simulation in identifying the most favorable surgical technique with an individualized approach, which could potentially improve the clinical outcome.

Case report: PICC line for a toddler with bilateral bidirectional Glenn shunt, Fontan circulation, and persistent left superior vena cava.

Performing peripherally inserted central catheters for children with bilateral bidirectional Glenn shunt, Fontan circulation, and persistent left superior vena cava differs from those with normal central venous anatomy. This study presents two PICC procedures for a toddler with this condition to demonstrate an accurate PICC approach for such children.

Impact of bilateral bidirectional Glenn anastomosis on staged Fontan strategy and Fontan circulation.

OBJECTIVES: The aim of this study was to identify the impact of bilateral bidirectional Glenn (BBDG) anastomosis on staged Fontan strategy and late Fontan circulation. METHODS: Of 267 patients who underwent bidirectional Glenn prior to Fontan completion between 1989 and 2013, 62 patients (23%) who underwent BBDG were enrolled in this study. Age at operation was 0.84 years (25th-75th percentile: 0.58-1.39). Thirty-three patients had heterotaxy syndrome (53%). The mean follow-up period was 12.7 ± 8.1 (max. 30.6) years. RESULTS: The overall survival rate at 15 years was 73%. Although 49 patients (79.0%) went on to Fontan completion, 12 patients (19.4%) died without achieving it. Thrombus formation and poor development in a central pulmonary artery were not observed, but obstruction of the superior vena cava (SVC) occurred in 8 patients (13%), mainly those with right atrial isomerism (P = 0.037). SVC obstruction was not, however, a risk factor for mortality (P = 0.097) or Fontan completion (P = 0.41). The shape of BBDG anastomosis, symmetricity of pulmonary blood flow, impingement of caval blood flow returning from the superior and inferior vena cavae or coexisting interrupted inferior vena cava with azygos or hemi-azygos continuation did not affect late Fontan outcomes, such as overall survival, freedom from protein-losing enteropathy or pulmonary arterio-venous malformation rates. CONCLUSIONS: SVC obstruction after BBDG frequently occurred, mainly in patients with right atrial isomerism; however, its direct impact on prognosis or achieving Fontan completion was not identified. Once Fontan circulation was established, the arrangement of the Fontan pathway did not affect late Fontan outcomes.

Bilateral bidirectional Glenn: outcome of off-pump technique.

OBJECTIVES: Off-pump bilateral bidirectional Glenn (b-BDG) poses a surgical challenge and may add complexity to the postoperative outcome especially regarding uniformity of the anastomosis and central pulmonary artery growth. Herein, we report early- and mid-term outcomes after off-pump b-BDG without using superior vena cava decompression techniques. METHODS: Ninety-seven consecutive patients, between 2009 and 2014, were included in this prospective study. All patients had complete pre- and postoperative clinical and detailed neurological assessments. Diagnosis and follow-up were done by echocardiography and cardiac catheterization for assessment of pulmonary artery anatomically and haemodynamically. Median follow-up period was 3.5 years. Perioperative variables, clinical outcome, morbidity, mortality and follow-up data were recorded. RESULTS: Hypoplastic right ventricle was present in 52 cases (53.6%) and hypoplastic left ventricle was present in 45 cases (46.4%). Mean superior vena cava pressure on clamping was 21.49 ± 3.04 mmHg. Mean total clamping time was 23.11 ± 3.44 min. Mean oxygen saturation increased from preoperative 69.22 ± 6.01% to 83.66 ± 3.97% after b-BDG construction (P-value ≤ 0.0001). The Nakata index increased from 288.47 ± 28.66 mm2/m2 to 303.64 ± 26.85mm2/m2 on follow-up (P-value ≤ 0.05). In-hospital mortality was 4 patients (4.1%) due to low-cardiac output. There were chylothorax in 9 patients (9.3%) and convulsions in 4 patients (4.1%) who were treated conservatively. CONCLUSIONS: Off-pump b-BDG can be conducted safely, with a uniform anastomosis that allows a good central pulmonary artery growth for subsequent Fontan completion. Moreover, avoiding the use of cardiopulmonary bypass is more economic and less hazardous.

Computational haemodynamic analysis of patient-specific virtual operations for total cavopulmonary connection with dual superior venae cavae.

OBJECTIVES: This study set out to design different types of total cavopulmonary connections (TCPC) with dual superior venae cavae (SVC), taking into account different sites for anastomosis from venae cavae to pulmonary arteries (PAs), and to compare haemodynamic features in these virtual operative designs. METHODS: The geometries of bilateral bidirectional Glenn (BBDG) connection and inferior vena cava (IVC) connected extracardiac conduit were reconstructed to three-dimensional configurations according to the magnetic resonance images (MRIs) of two patients at the same age, and virtual operations were designed to create four possible TCPC models under the guidance of paediatric cardiac surgeons. Computational fluid dynamic (CFD) simulations were performed in each model at five predetermined pulmonary flow splits, to predict postoperative blood flows. The same boundary conditions were applied on each model, in order to simplify the analysis of the influence of configurations on the flow characteristics. Control volume power losses and energy efficiency in different models were calculated and compared. Flow patterns in the models were demonstrated by streamlines corresponding to the venae cavae. RESULTS: When the flow rate of the right pulmonary artery (RPA) was 40-60% of the total pulmonary flow, control volume power loss was lower than the other three models in the model of TCPC 2 and was higher than the other three models in the model of TCPC 4. CONCLUSIONS: For this patient, anastomosing the left superior vena cava (LSVC) and right superior vena cava (RSVC) on the PAs close together will cause higher power loss and lower energy efficiency in the TCPC connection. If the LSVC and RSVC had been connected to the PAs as near as possible to stimulate growth of the central PAs when performing I-stage BBDG procedure, the extracardiac conduit from IVC would be better connected just under the anastomotic site in the following TCPC procedure to avoid high power loss.