Right atrium and superior vena cava pressure measurements in a novel animal model to study one and a half ventricle repair as compared to Fontan type procedure

Abstract

Background & Objectives: To evaluate the advantages of the one and a half ventricle repair on maintaining a low pressure in the inferior vena cava district. Also evaluate the competition of flows at the superior vena cava – right pulmonary artery anastomosis site, in order to understand the hemodynamic interaction of a pulsatile flow in combination to a laminar one. Materials & Methods: Adult rabbits (n=30) in terminal anaesthesia with a follow up of 8 h were used, randomly distributed in three experimental groups: Group 1: animals with an anastomosis between superior vena cava and right pulmonary artery, as a model of one and one half ventricle repair; Group 2: animals with the cavopulmonary anastomosis followed by clamping of the right pulmonary artery proximal to the anastomosis; and Group 3: sham animals. Pressures of superior vena cava and pulmonary arteries were afterwards measured, in a resting condition as well as after induced pharmacological stress test.Results: In Group 1, superior vena cava pressure was significantly higher, while venous pressure in the inferior vena cava – right atrium district was constant or lower in comparison with the other groups. After stress test, the pressure in the superior vena cava and the heart rate both increased further, but the right ventricular, right atrial and pulmonary artery pressures remained similar to the values in a resting condition. This proved that the inferior vena cava return was well-preserved, and no venous hypertension was present in the inferior vena cava district even after stress test (good exercise tolerance).Conclusion: One and one half ventricle repair can be considered a good surgical strategy for maintaining a low pressure in the inferior vena cava district with potential for right ventricle growth, restoring the more physiological circulation in borderline or failing right ventricle conditions. The experiment presented a positive finding in favour of one and one half ventricle repair, as compared to Fontan type procedure.

Numerical Simulation of the Effect of Pulmonary Vascular Resistance on the Hemodynamics of Reoperation After Failure of One and a Half Ventricle Repair

“…Psvc in 1.5VR is greater than Pivc due to the characteristics of 1.5VR (Bhattarai et al, 2017). mPsvc\mPivc of 1.5VR is the largest among the three kinds of procedures, that is because in 1.5VR , the superior vena cava anastomoses to the pulmonary artery, and Psvc increases due to the influence of Pa (Bhattarai et al, 2017). During the period Ts, the right ventricle is in systole, resulting in Ppa greater than Psvc in 1.5VR , then more blood would flow from the pulmonary artery to the superior vena cava; thus, the waveform of Qsvc is negative during Ts.…”

“…With the increase of PVR, Pa of all three surgical methods increases, resulting in different degrees of pulmonary hypertension (Palazzini et al, 2017). Psvc in 1.5VR is greater than Pivc due to the characteristics of 1.5VR (Bhattarai et al, 2017). mPsvc\mPivc of 1.5VR is the largest among the three kinds of procedures, that is because in 1.5VR , the superior vena cava anastomoses to the pulmonary artery, and Psvc increases due to the influence of Pa (Bhattarai et al, 2017).…”

“…The operation consists of the bidirectional cavopulmonary shunt (BCPS) and the correction of the intracardiac malformation, and aims to make the right ventricle bear only blood flow of the lower body; thus, the sum of the left and right ventricle stroke work (Ptotal) won't change while the right ventricular volume load is reduced (Barron, 2018). This operation maintains a low right atrial pressure, pulsating pulmonary blood flow and adequate blood oxygen during the short/medium term (Bhattarai et al, 2017;Talwar et al, 2018), which reduces the occurrence of poor prognosis such as the biventricular repair induced right heart failure (Talwar et al, 2018) and the single ventricular repair induced circulatory failure (Sharma et al, 2012;Talwar et al, 2018).…”