Assessment of superior cavo-pulmonary anastomoses (Glenn shunt) by cardiac magnetic resonance imaging in comparison with multi-slice computed tomography

Background Multi-slice computed tomography (MSCT) angiography is the gold standard imaging modality to evaluate the patency of Glenn shunt and the presence of veno–veno collaterals. The goal of this study is to evaluate the ability of two cardiac magnetic resonance imaging (MRI) techniques to assess the patency of Glenn shunt and the presence of veno–veno collaterals compared to MSCT angiography. Results Patients with Glenn shunt had MSCT angiography and cardiac MRI using two techniques: TWIST (Time-resolved angiography With Stochastic Trajectories) and the three-dimensional (3D) post-contrast whole heart techniques. MSCT angiography and cardiac MRI images were post-processed for quantitative and qualitative assessment of Glenn shunt and veno–veno collaterals. Our study included 29 patients (17 male, 59%) with Glenn shunt, the median age was 22 years (range 3–36 years). 3D post-contrast whole heart images give similar results compared to MSCT angiography results in the evaluation of Glenn shunt and veno–veno collaterals, 100% agreement in Glenn shunt visualization and agreement was 86.2% in the detection of veno–veno collaterals with a perfect agreement (kappa = 1) as regards their proximal connection to superior vena cava (SVC). While TWIST showed lower agreement compared to MSCT angiography results, 87.5% agreement in Glenn shunt visualization and agreement was 68.9% in the detection of veno–veno collaterals with poor agreement (kappa = 0.266) as regards their proximal connection to SVC. Conclusions 3D post-contrast whole heart MRI images have similar results as MSCT angiography in the evaluation of superior cavo-pulmonary anastomosis and can be a good and safer alternative to MSCT angiography.

The Failed Bidirectional Glenn Shunt: Risk Factors for Poor Outcomes and the Role of Early Reoperation

Background: Bidirectional Glenn shunt (BDG) failure carries high morbidity and mortality but the clinical factors associated with failure and the optimal management strategy are understudied. Methods: A total of 217 patients undergoing BDG at our institution between 1989 and 2020 were retrospectively reviewed and categorized as success or failure. Failure was defined as the need for reoperation (BDG takedown, reoperation for correction of cardiac defect, and/or transplantation) at any time postoperatively; operative mortality (death attributable to BDG malfunction occurring during the index hospitalization for BDG or within 30 days of discharge); or late mortality (death directly attributable to BDG malfunction occurring prior to Fontan or next-stage palliation). Univariate and binary logistic regression analyses were performed. Results: BDG failure occurred in 14 (6.5%) patients. Univariate predictors were: hypoplastic left heart syndrome ( P = .037), right ventricular (RV) dominance ( P = .010), greater pre-BDG pulmonary vascular resistance (PVR) ( P = .012), concomitant atrioventricular valve repair ( P = .020), prolonged pleural drainage ( P = .001), intensive care unit ( P<.001) and hospital ( P = .002) stays, and extracorporeal membrane oxygenation (ECMO) requirement ( P<.001). Multivariate predictors were: RV dominance ( P = .002), greater PVR ( P = .041), ICU ( P<.001) and hospital ( P = .020) stays, and need for ECMO ( P<.001). As many as 10 of 14 (71%) patients with BDG failure died. Reoperation was performed for 10 patients with BDG failure. Five reoperation patients survived until discharge, with four patients alive at last follow-up (mean 7.9 years). Survivors underwent reoperation earlier than nonsurvivors (36 vs. 94 days). Conclusions: BDG failure carries high mortality, but preoperative predictors and postoperative indicators of failure exist. Early BDG takedown and insertion of aorta-pulmonary shunt may allow survival.

BIDIRECTIONAL GLENN SHUNT AND REPAIR OF TOTAL ANOMALOUS PULMONARY VENOUS CONNECTION IN A 3 YEARS OLD CHILD WITH HETEROTAXY SYNDROME: A CASE REPORT

Right Atrial Isomerism (RAI) and total anomalous pulmonary venous connection (TAPVC) is a rare condition with very high mortality in neonatal period, but outcomes may be better in older children. A cyanotic 3 years old boy with dyspnea and growth retardation diagnosed with RAI and supracardiac type of TAPVC undergone a successful repair of TAPVC and simultaneous Glenn shunt. Older patients with RAI may be a distinct, more suitable group for surgical repair.

The Anaesthetic Management of a Parturient with an Ebstein Anomaly and Prior Bidirectional Glenn Shunt

Parturients with Ebstein anomaly are an anaesthetic challenge due to the spectrum of disease. Patients palliated with bidirectional Glenn shunts are susceptible to right heart dysfunction due to the physiological changes during parturition. We present a 28-year-old primigravida with Ebstein anomaly surgically managed by a bidirectional Glenn shunt. Echocardiograms showed normal right ventricular function despite reported dyspnea as the pregnancy progressed. Following a comprehensive plan developed during multidisciplinary prenatal meetings, she safely delivered. In this case report, we discuss the preoperative evaluation, management of labour and delivery, and postpartum planning of parturients with palliated Ebstein anomaly.

CFD Modeling of Blood Flow in a Bidirectional Glenn Shunt and a Combined Bidirectional Glenn and Blalock-Taussig Shunt

Cyanosis or “Blue Baby Syndrome,” is an infant disorder which affects the newly born babies whose skins turn blue or purple because of lack of required blood flow between heart and lung due to pulmonary vascular blockage. Many patients may also have stenosis in vessels. If there is not enough blood flow from heart to the lung, lack of oxygen will cause platelet aggregation and coagulation resulting in elevated wall shear stress which may potentially result in death. In order to address the congenital defect and increase blood flow and oxygen saturation levels within the blood pumping system, a biological shunt is usually planted between innominate veins and left and right pulmonary arteries. The well-known examples are Blalock-Taussig shunt (BT shunt) between right ventricle and pulmonary artery and bidirectional Glenn shunt (BGS) between innominate veins and pulmonary arteries. The goal of this paper is to study the hemodynamics of BGS, wherein the blood flow goes through superior vena cava (SVC), innominate and subclavian veins and pulmonary arteries. In another simulation, Blalok-Taussing shunt (BTS) is also included along with the BGS. In BTS, the blood directly flows between innominate and pulmonary artery. The models are created with SolidWorks and Blender software based on real patient aorta model parameters. The commercial CFD software ANSYS is used to simulate the blood flow. CFD simulations are performed for blood flow (1) in patient specific aorta model without BGS and (2) in patient specific model with both BGS and BTS. The results for distribution of pressure, velocity and wall shear stress are obtained and analyzed to evaluate the performance of BGS alone and with both BGS and BTS. The computations are compared with limited available clinical data. This study demonstrates how CFD can be effectively utilized in the design of medical devices such as BGS and BTS and to improve the clinical outcomes in patients.