Dual chamber stent prevents organ malperfusion in a model of donation after cardiac death

Abstract

Background: The paradigm for donation after cardiac death subjects donor organs to ischemic injury. A dual-chamber organ perfusion stent would maintain organ perfusion without affecting natural cardiac death. A center lumen allows uninterrupted cardiac blood flow, while an external chamber delivers oxygenated blood to the visceral vessels.

Methods: A prototype organ perfusion stent was constructed from commercial stents. In a porcine model, the organ perfusion stent was deployed, followed by a simulated agonal period. Oxygenated blood perfused the external stent chamber. Organ perfusion was compared between controls (n = 3) and organ perfusion stent (n = 6). Finally, a custom, nitinol, dual chamber organ perfusion stent was fabricated using a retrievable "petal and stem" design.

Results: Endovascular organ perfusion stent deployment achieved visceral isolation without adverse impact on cardiac parameters. Visceral oxygen delivery was 4.8-fold greater compared with controls. During the agonal period, organs in organ perfusion stent-treated animals appeared well perfused in contrast with the malperfused controls. A custom nitinol and polyurethane organ perfusion stent was recaptured easily with simple sheath advancement.

Conclusion: An organ perfusion stent maintained organ perfusion during the agonal phase in a porcine model of donation after cardiac death organ donation without adversely affecting cardiac function. Ultimately, the custom retrievable design of this study may help resolve the critical shortage of donor organs for transplant.

Figure 1. An Organ Perfusion Stent compartmentalizes blood flow

(A) An OPS consolidates multiple branches into a single isolated organ compartment (Zone 2) that is separate from the systemic circulation (Zone 1). (B) Cardiac Perfusion: Blood from the heart passes through the large central lumen of the organ perfusion stent to perfuse the lower body and then returns through veins to the heart. (C) Abdominal Perfusion: Blood from a percutaneous venous cannula is oxygenated and pumped back to the external stent compartment where isolated visceral arterial branches are perfused.

Figure 2. A Commercial Hybrid OPS

An OPS was fashioned from commercial iliac limb seal zones, a covered stent and a perfusion lumen (the blue catheter is a placekeeper for a guidewire). The center lumen carries agonal bloodflow from the heart while the perfusion lumen delivers oxygenated blood to the external compartment. The stent is delivered through a standard endovascular sheath.

Figure 3. Angiography of an OPS in vivo illustrates the separate stent chambers

(A) Cardiac Perfusion: including the center lumen (dotted parallel lines), and top end of the stent (arrow). (B) Abdominal Organ Perfusion: The external chamber isolates perfusion of the four visceral vessels.

Figure 4. An OPS maintains perfusion in the agonal period

A dusky appearance consistent with malperfusion of the kidney (A) and liver (C) in a control animal after a 60 minute agonal period. By contrast, an animal treated with an OPS reveals normal color of the kidney (B) and liver (D) suggesting preserved perfusion.

Figure 5. A custom retrievable Organ Perfusion Stent (OPS)

(A) A “petal and stem” stent design includes “petals” that remain attached to a long “stem” to facilitate retrieval. The nitinol scaffold includes a narrower center section to create an external perfusion compartment (B) The stent covered with an electrospun PEUU. (C) Rapid retrieval of the OPS by advancement of the vascular sheath is demonstrated within a clear plastic conduit.

Figure 6. Demonstration of a modular perfusion lumen

(A) The stent shown alongside the 12 Fr perfusion lumen, which is guided over a wire (B) for modular docking with the main OPS for a fluid tight seal (C). The complete OPS after docking of the perfusion lumen.