C. C. Go1, J. M. Kuhn3, Y. Chen2, Y. Chun2, B. Tillman1,3 1University Of Pittsburgh Medical Center,Division Of Vascular Surgery,Pittsburgh, PA, USA 2Swanson School Of Engineering,Department Of Industrial Engineering,Pittsburgh, PA, USA 3University Of Pittsburgh,McGowan Institute Of Regenerative Medicine,Pittsburgh, PA, USA
Introduction: Traumatic and iatrogenic injuries of the inferior vena cava (IVC) present a difficult and life-threatening problem. Our group has previously demonstrated the feasibility of a retrievable RESCUE stent for angiographic control of hemorrhage in a terminal model. The goals of this present study were to evaluate hemorrhage control, demonstrate continued venous return angiographically, and characterize hemodynamics of the animal before and after stent deployment using a survival porcine model of caval injury.
Methods: A retrievable RESCUE stent was constructed with a previously described “petal and stem” design with a nitinol scaffold and then covered with a sleeve of polytetrafluoroethylene. Three anesthetized pigs underwent standardized 22-French injury of the IVC. Animals were passively hemorrhaged for 1200 mL followed by stent deployment from a percutaneous femoral access and imaged with venography. After one hour, the RESCUE stent was retrieved, the injury repaired, and resuscitation with cellsaver blood and crystalloid was completed. Animals were followed for 48 hours postoperatively.
Results: Upon injury, 1200 mL of blood loss occurred in under 5 minutes. Deployment of the RESCUE stent took less than 2 minutes under fluoroscopy and provided instantaneous hemostasis, while venography confirmed normal venous return to the heart (Figure 1). The average mean arterial pressure of the three animals was 47 mm Hg at baseline, fell to 32 mmHg after injury, and returned to 44 mmHg after stent placement and resuscitation. Central venous pressures followed a similar trend: 10 mmHg prior to injury, 8 mmHg post-injury, and 10 mmHg post-stent/resuscitation. The stent was retrieved easily with sheath advancement at the time of permanent vascular repair. All animals survived the 48-hour postoperative period with stable hemoglobin levels and absence of organ failure as determined by serum chemistries.
Conclusion: A RESCUE stent provided rapidly-deployed hemorrhage control in a porcine model of caval injury. Its use reversed hemodynamic instability and allowed for eventual permanent repair over an hour after injury with successful postoperative recovery. This approach may be useful for “damage control” when exposure is limited due to massive caval bleeding or when vascular expertise is not immediately available. Further investigation may reveal whether the continued blood flow offered by the RESCUE stent translates to improved outcomes as compared to balloon occlusion or IVC crossclamping.
