Balancing pulmonary blood flow: Theory, in vitro measurements, and clinical correlation of systemic-to-pulmonary shunt banding

Hemodynamic Response to Device Titration in the Shunted Single Ventricle Circulation: A Patient Cohort Modeling Study

Clinical outcomes of ventricular assist device (VAD) support for shunted single ventricle patients trail the larger population due in part to the challenges in optimizing VAD support and balancing systemic and pulmonary circulations. We sought to understand the response to VAD titration in the shunted circulation using a lumped-parameter network modeling six patient-specific clinical cases. Hemodynamic data from six patients (mean body surface area = 0.30 m2) with a systemic-to-pulmonary shunt was used to construct simulated cases of heart failure and hemodynamic response to increasing VAD flow from 5 to 10 L/min/m2. With increasing VAD flow, the pulmonary arterial pressure stayed relatively constant in five patient cases and increased in one patient case. The mean VAD flow needed to attain an arterial-venous O2 saturation difference of 30% was 6.5 ± 1.2 L/min/m2, which is higher than that in the equivalent nonshunted scenario due to the partial diversion of flow to the pulmonary circulation. The hemodynamic responses to VAD support can vary significantly between specific patient cases; therefore hemodynamic modeling may help guide an individualized approach to perioperative VAD management in the shunted single-ventricle circulation and to understand the patients who may benefit the most from VAD support.

Feasibility of lung ultrasound to assess pulmonary overflow in congenital heart disease children

BACKGROUND

Pulmonary overflow (PO) is one of the most common complications in congenital heart disease (CHD) children with an incidence of 48-60% approximately. This study explored the feasibility of using lung ultrasound (LUS) to assess pulmonary overcirculation in CHD children and compare the diagnostic performance of LUS and chest radiography (CXR) for the detection of pulmonary overcirculation.

METHOD

The upper anterior area, lower anterior area, upper lateral area, and lower posterior area, in each hemithorax were scanned in 59 children in the supine position. A-lines, B-lines in each scanned region were recorded, and the worst LUS abnormality in the video clip was considered to characterize the examined region. Sensitivity, specificity, positive and negative predictive values, and diagnostic accuracy of LUS and CXR were compared using computed tomography (CT) as a standard criterion.

RESULTS

PO was diagnosed in 53% (31/59), 63% (37/59), and 51% (30/59) children with CT, CXR, and LUS, respectively. The sensitivity, specificity, and diagnostic accuracy of PO were 96%, 94%, and 95% for LUS and 74%, 50%, and 63% for CXR. The percentage of mild, moderate, and severe PO diagnosed via LUS were 31% (18/59), 19% (11/59), and 2% (1/59), respectively. Furthermore, the PO incidence diagnosed by LUS in CHD children less than 1 year old were significantly higher than those beyond 1 year old.

CONCLUSION

LUS is a noninvasive and useful tool for the detection and assessment of PO in CHD children at the operating room, and is better than CXR in sensitivity and specificity, comparable to CT.