Background: Ex vivo vascular bioreactors that enable interventions in arteries from slaughterhouse surplus hearts present valuable alternatives to animal models to test cardiovascular stents. However, the knowledge for stent implantation during ex vivo culture in slaughterhouse coronary arteries is limited. The objective of the study is two-fold: first, to determine culture settings, the time point and optimal conditions for in-culture stent implantation using surplus right coronary arteries (RCAs) from swine with known in vivo RCA diameters; and second, to implement the gained insights to culture and stent RCAs obtained from slaughterhouse hearts (unknown in vivo diameter). Methods: Swine RCAs were mounted, cultured and stented in an ex vivo vascular bioreactor (VABIO) under conditions of flow and pressure. The bioreactor culture and stenting protocols were optimized using a step wise approach. In Step 1, the RCAs dissected from in-house swine hearts, with known diameters, were cultured until endothelialized as the ideal time point for stenting, and the stent implantation procedure was optimized. In Step 2, the successful ex vivo stent implantation procedure was repeated in slaughterhouse RCAs. Structural changes of the RCAs were assessed by ultrasound imaging during culture. The morphology of the RCAs at the end of culture was assessed by histology. Results: The RCAs adapted to the ex vivo environment, stabilizing their diameter in the range of the in vivo diameter after day 3, which was selected as the earliest time point for stenting. Because stent implantations caused mural dissections in the RCAs, visible with ultrasound imaging and confirmed by histology, we developed an external support for the RCA. This was found to be critical for better physiological intravascular pressures and to minimize dissections upon stent implantation. Finally, the stent implantation procedure was successfully replicated in slaughterhouse arteries. Conclusions: Our study demonstrates the feasibility of in-culture ex vivo stent implantation in the VABIO, providing important requirements and useful insights for in vivo mimicking stent implantation, for future investigations in slaughterhouse arteries.

Background: X-ray digital subtraction angiography (DSA) is the imaging modality for peri-procedural guidance and treatment evaluation in (neuro-) vascular interventions. Perfusion image construction from DSA, as a means of quantitatively depicting cerebral hemodynamics, has been shown feasible. However, the quantitative property of perfusion DSA has not been well studied. Purpose: To comparatively study the independence of deconvolution-based perfusion DSA with respect to varying injection protocols, as well as its sensitivity to alterations in brain conditions. Methods: We developed a deconvolution-based algorithm to compute perfusion parametric images from DSA, including cerebral blood volume (CBV (Figure presented.)), cerebral blood flow (CBF (Figure presented.)), time to maximum (Tmax), and mean transit time (MTT (Figure presented.)) and applied it to DSA sequences obtained from two swine models. We also extracted the time intensity curve (TIC)-derived parameters, that is, area under the curve (AUC), peak concentration of the curve, and the time to peak (TTP) from these sequences. Deconvolution-based parameters were quantitatively compared to TIC-derived parameters in terms of consistency upon variations in injection profile and time resolution of DSA, as well as sensitivity to alterations of cerebral condition. Results: Comparing to TIC-derived parameters, the standard deviation (SD) of deconvolution-based parameters (normalized with respect to the mean) are two to five times smaller, indicating that they are more consistent across different injection protocols and time resolutions. Upon ischemic stroke induced in a swine model, the sensitivities of deconvolution-based parameters are equal to, if not higher than, those of TIC-derived parameters. Conclusions: In comparison to TIC-derived parameters, deconvolution-based perfusion imaging in DSA shows significantly higher quantitative reliability against variations in injection protocols across different time resolutions, and is sensitive to alterations in cerebral hemodynamics. The quantitative nature of perfusion angiography may allow for objective treatment assessment in neurovascular interventions.