Vascular thrombosis during support with continuous flow ventricular assist devices: correlation with computerized flow simulations.
Continuous flow pumps are increasingly used to treat severe heart failure. These pumps alter flow physiology by lowering pulsatility in the arterial circulation. In patients with peripheral stenosis, continuous flow pumps may lead to thrombosis of peripheral vessels, possibly predisposing to vascular thrombosis in areas of non-flow-limiting stenosis. The authors performed a computerized flow modeling simulation to analyze the effects of altered hemodynamics in a stenotic area. Drawing on previous clinical experience, we modeled a stenotic area in the common carotid artery. Computerized flow modeling revealed blood stagnation zones with low shear stress and velocity adjacent to the stenotic area during nonpulsatile flow. Such stagnation was not present during pulsatile flow. These results indicate a mechanism by which altered physiologic flow may accelerate occlusion of arterial conduits in patients with preexisting stenosis. This finding may be important for patients with continuous flow devices who have peripheral vascular disease; therefore, further study is warranted.
Kar
Biswajit
B
Cardiopulmonary Transplant Service, Texas Heart Institute, Houston, TX 77030, USA. bkar6@aol.com
Delgado
Reynolds M
RM
Radovancevic
Branislav
B
Myers
Timothy J
TJ
Wadia
Yasmin
Y
Letsou
George V
GV
Riaz
Imran
I
Metcalfe
Ralph
R
Gregoric
Igor
I
Harting
Matthew T
MT
D001783:Blood Flow Velocity; D003198:Computer Simulation; D003326:Coronary Circulation / Q000502:physiology*; D023921:Coronary Stenosis / Q000503:physiopathology*; D006333:Heart Failure / Q000628:therapy*; D006353:Heart-Assist Devices / Q000009:adverse effects*; D006801:Humans; D012307:Risk Factors; D013927:Thrombosis / Q000209:etiology* / Q000503:physiopathology