Development and Validation of a Test Setup for the Assessment of Large-Diameter Tubular Vascular Graft Compliance

Abstract

Cardiovascular diseases are increasingly prevalent and can cause multiple forms of vessel degeneration. Commonly used vascular grafts, however, do not match the native vessels’ compliance and can therefore negatively influence hemodynamics. Without precise measurement methods, differences in compliance of large-diameter tubular prostheses remain difficult to compare and quantify. This study presents a dedicated modular in vitro test setup designed to quantify the compliance of large-diameter tubular vascular prostheses in accordance with ISO 7198. This stand-alone test setup consists of a reservoir, a pulsatile pneumatic pump and a compliance chamber, as well as three-dimensionally printed prosthesis holders allowing for the analysis of various implants. Pressure, graft diameter, fluid temperature, implant elongation and flow are continually monitored. Sensor-based measurements are visualized on a touchscreen. To validate the test setup, the dynamic radial compliance of novel electrospun prosthesis prototypes and porcine aortas was evaluated. The setup enables precise adjustment of systolic and diastolic pressure levels relevant for fluid-dynamic assessment (measured ranges 90/50, 120/80, and 150/110 mmHg). Pressure stability can be maintained within ±0.75 mmHg. Temperature can be held at 37°C. Graft diameters are measured with a precision of ±0.01 mm. With these controlled conditions, the measurement setup fulfills the requirements specified in DIN EN ISO 7198 for vascular graft testing. Dynamic radial compliance of the prosthesis prototypes (n=8) was measured at 1.85±1.7 %/100 mmHg, 1.68±1.8 %/100 mmHg, and 1.85±1.7 %/100 mmHg, for physiological pressures of 90/50 mmHg, 120/80 mmHg, and 150/110 mmHg, respectively. Corresponding values for porcine aortas (n=5) were markedly higher (16.6±2.5 %/100 mmHg, 10.4±3.28 %/100 mmHg, and 6.3±2.26 %/100mmHg). The presented test setup enables precise simulation of physiological pressure ranges and highresolution measurement of mechanical and fluid dynamic parameters. The system therefore provides a practical platform for standardized in vitro compliance testing of vascular implants.