Abstract TP81: Flow Independent Dynamics in Aneurysm (FIDA): Pressure Measurements within an Aneurysm Before and After Partial and Complete Flow Impairment
BACKGROUND: The correlation between different hemodynamic variables and aneurysm growth and rupture has not been fully understood. We aimed to study intravascular and peri-vascular pressure in the aneurysm after partial and complete flow impairment within the aneurysm.
MATERIALS AND METHODS: A silicone model of an 8 mm sized aneurysm (neck diameter: 5mm, vessel size: 4 mm) was used. The aneurysm wall was encapsulated and sealed within a 5ml syringe filled with saline and a pressure sensor guidewire (PrimeWire, Volcano Corp.) providing pressure changes in the peri-vascular compartment (outer aneurysm wall). Through a 5 F guiding catheter, a second pressure sensor guidewire was advanced inside the aneurysm sac. The aneurysm connected to a pulsatile fluid pump. Both pressure sensors continuously measured pressure inside and outside the aneurysm under pulsatile flow under the following conditions: 1) baseline (reference); 2) a 16 mm by 3.75 mm flow diverting stent (ev3, Irvine, California) deployed in front of the aneurysm; 3) two flow diverting stents (16 mm by 3.5 mm) were deployed; and 4) a covered stent (4 mm by 16 mm VeriFlex cronory artery stent covered with rubber sheet) was deployed.
RESULTS: Mean baseline pressures inside and outside the aneurysm were 55 mmHg (range 120-40 mmHg) and 15 mmHg (range 40-8 mmHg), respectively. There was no change in pressure inside and outside the aneurysm after deploying the first and second flow diverting stents (partial flow impairment) and pressure remained at 55 mmHg and 15 mmHg inside and outside the aneurysm, respectively. The pressure recording from outside the aneurysm dropped from 15mmHg to zero after deploying the covered stent (complete flow impairment). There was no change in pressure inside the aneurysm after deploying the covered stent. Mean pressure within the aneurysm was 55 mmHg and it remained the same after covered stent deployment.
CONCLUSION: Our findings suggest a major discordance between the pressures within the aneurysm and partial or complete flow impairment (flow-independent). The outer wall pressure is reduced after covered stent placement. These finding may assist physicians in better understanding of aneurysm hemodynamics and rupture after flow diverting stent deployment.
- © 2012 by American Heart Association, Inc.