In Silico Evaluation of a Self-powered Venous Ejector Pump for Fontan Patients

PURPOSE

The Fontan circulation carries a dismal prognosis in the long term due to its peculiar physiology and lack of a subpulmonic ventricle. Although it is multifactorial, elevated IVC pressure is accepted to be the primary cause of Fontan's high mortality and morbidity. This study presents a self-powered venous ejector pump (VEP) that can be used to lower the high IVC venous pressure in single-ventricle patients.

METHODS

A self-powered venous assist device that exploits the high-energy aortic flow to lower IVC pressure is designed. The proposed design is clinically feasible, simple in structure, and is powered intracorporeally. The device's performance in reducing IVC pressure is assessed by conducting comprehensive computational fluid dynamics simulations in idealized total cavopulmonary connections with different offsets. The device was finally applied to complex 3D reconstructed patient-specific TCPC models to validate its performance.

RESULTS

The assist device provided a significant IVC pressure drop of more than 3.2 mm Hg in both idealized and patient-specific geometries, while maintaining a high systemic oxygen saturation of more than 90%. The simulations revealed no significant caval pressure rise (< 0.1 mm Hg) and sufficient systemic oxygen saturation (> 84%) in the event of device failure, demonstrating its fail-safe feature.

CONCLUSIONS

A self-powered venous assist with promising in silico performance in improving Fontan hemodynamics is proposed. Due to its passive nature, the device has the potential to provide palliation for the growing population of patients with failing Fontan.

The Relationship of Pleural and Pericardial Effusion With Pulmonary Hemodynamics in Patients With Pulmonary Hypertension

BACKGROUND

The relationship between the presence of pleural and pericardial effusion in reference to hemodynamic parameters remains unclear in ambulatory patients with pulmonary hypertension (PH).

METHODS

Consecutive patients who underwent right catheterization (RHC) for the evaluation of pulmonary hypertension were enrolled. Point-of- care ultrasound was performed prior to the RHC to determine the presence of pleural effusion and pericardial effusion. We conducted a cross-sectional study to determine the association between presence of pericardial and pleural effusion with pulmonary hemodynamic variables.

RESULTS

Twenty-five (78.1%) of 32 patients had evidence of PH by RHC. Mean pulmonary artery pressure of the population was 40.6 mmHg, and 68% (17/25) had WHO group I PH. Six (24.0%) of 25 PH patients had pleural effusions identified, of which 4 out of 6 (66.7%) had a pulmonary artery wedge pressure >15 mmHg. Eleven (44.0%) of the 25 PH patients were also found to have pericardial effusions, and most of those patients 10/11(90.9%) had an elevated right atrial pressure >10 mmHg. The presence of a pleural effusion was associated with a pulmonary artery wedge pressure >15 mmHg (p = 0.032) and the presence of a pericardial effusion was associated with a right atrial pressure >10 mmHg (p = 0.004). Detection of pleural effusion had a poor positive predictive value (67%) for the presence of pulmonary venous hypertension, whereas presence of a pericardial effusion was highly predictive (89%) of the presence of systemic venous hypertension.

CONCLUSIONS

Systemic venous hypertension was associated with the presence of pericardial effusions, while pulmonary venous hypertension is associated with pleural effusion development in ambulatory patients with pulmonary hypertension.