A lumped-parameter approach for designing a novel pulsatile bioreactor for ex-vivo studies of human saphenous vein remodeling

After coronary artery bypass grafting (CABG), the hemodynamic conditions experienced by the saphenous veins are similar to those experienced by coronary arteries: pulsatile pressure (80-120 mmHg), pulsatile flow (mean flow rate of 250 ml/min), and elevated shear stress (1-7 Pa). Here we present a novel pulsatile platform for studying the human saphenous vein early remodeling events after CABG. The system was designed in order to apply CABG-like pressure/flow stimulation patterns to the hosted human saphenous vein segments, i.e. a pulsatile pressure oscillating between a diastolic minimum and a systolic maximum in counter-phase with a pulsatile flow rate. Functional tests revealed good fitting of simulated and measured tracings and the ability of the pulsatile platform to mimic the complexity of the coronary hemodynamic environment with good fidelity in comparison with state-of-the-art devices. This system will enable us to study the biological response of human saphenous veins to CABG conditioning ex vivo, in currently ongoing experiments.