Thrombosis in centrifugal pumps: location and composition in clinical and in vitro circuits.
OBJECTIVE
Extracorporeal membrane oxygenation (ECMO) is a form of cardiopulmonary mechanical life support for critically ill patients. ECMO is burdened by both thrombotic and hemorrhagic complications. Recently there has been a clinical shift from roller pumps to centrifugal pumps. In this study, we report on bulk thrombus formation within pumps recovered from clinical use. We then replicate this thrombus formation in vitro.


METHODS
Clinical pediatric ECMO circuits driven with the Sorin Revolution were collected from 16 patients. The location and extent of thrombus formation in the pumps were recorded. Pump heads were also tested in a laboratory circulatory loop. The location, extent, and appearance of the thrombi were recorded. Thrombi were examined histologically using Carstairs' stain.


RESULTS
Gross thrombus was observed in all pump heads at the stainless steel bearing at the inlet. In 19% of the pumps larger thrombi grew into the head over the cone and along the vanes. The thrombi were adherent and cohesive upon extraction. The thrombus formation was strikingly similar between the clinical pump heads and in vitro pump heads. Histology of both clinical and experimental samples exhibited a platelet-rich thrombus.


CONCLUSIONS
Our studies have revealed platelet-rich thrombus in clinical and in vitro circuits. The location and composition of the thrombi suggest that the exposed metal shaft was initially covered by contact activated coagulation followed by large-scale growth by rapid platelet accumulation from high shear rates at the inlet. The in vitro system may be used to further identify the mechanisms for pump thrombus and test new designs.
GWW School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA - USA.
Susan M
SM
Hastings
Department of Pediatrics, Emory School of Medicine, Atlanta, GA - USA.|Children's Healthcare of Atlanta, Atlanta, GA - USA.
Shriprasad R
SR
Deshpande
Children's Healthcare of Atlanta, Atlanta, GA - USA.
Scott
S
Wagoner
Department of Pediatrics, Emory School of Medicine, Atlanta, GA - USA.|Children's Healthcare of Atlanta, Atlanta, GA - USA.
Kevin
K
Maher
GWW School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA - USA.
David N
DN
Ku
D001792:Blood Platelets; D004867:Equipment Design; D015199:Extracorporeal Membrane Oxygenation / Q000009:adverse effects*; D006801:Humans; D013927:Thrombosis / Q000209:etiology*