Analysis of Thrombotic Deposits in Extracorporeal Membrane Oxygenators by Multidetector Computed Tomography

Abstract

Oxygenator thrombosis is a serious complication in extracorporeal membrane oxygenation (ECMO) and may necessitate a system exchange. Coagulation and fibrinolysis parameters, flow dynamics, and gas transfer performance are currently used to evaluate the degree of oxygenator thrombosis, but there is no technical approach for direct visualization and quantification of thrombotic deposits within the membrane oxygenator (MO). We used multidetector computed tomography (MDCT) with three-dimensional postprocessing to assess the incidence of oxygenator thrombosis, to quantify thrombus extent, and to localize clot distribution. Twenty heparin-coated MOs after successful weaning were analyzed. Mean ECMO support time was 7 ± 4 days, mean activated partial thromboplastin time (aPTT) during ECMO was 59 ± 20 seconds. Thrombotic deposits were detected in all MOs. The mean clot volume was 51.7 ± 22.3 cm. All thrombotic deposits were located in the venous, i.e., inlet part of the device, without apparent evidence of embolization in patients. There was no correlation between clot volume and ECMO support time or aPTT. Clot formation within the MO is a common finding in ECMO despite adequate systemic anticoagulation. The clinical significance of thrombus formation and its influence on gas exchange capacity and hemostatic complications have to be addressed in further studies.

Comparison between clinical indicators of transmembrane oxygenator thrombosis and multidetector computed tomographic analysis

“…As far as the ECMO systems are currently conceived, blood is pushed by the impeller toward the base of the oxygenator resulting in a high blood flow zone at the bottom and a low blood flow zone at the apical corner. Conversely, in contrast with our findings, a recent article on the same topic [9] revealed predominance of clot formation in the lower part of the preoxygenation compartment.…”

“…To detect MOT under ex vivo conditions, multidetector computed tomographic (MDCT) analysis has been recently proposed as a potential alternative to oxygenator dissection [8]. This was recently substantiated by the same research group, which characterized clot distribution inside the membrane oxygenator using MDCT [9]. The objective of this study is to describe the concordance between routinely used clinical parameters and MDCT in detecting MOT.…”

Technical Indicators to Evaluate the Degree of Large Clot Formation Inside the Membrane Fiber Bundle of an Oxygenator in an In Vitro Setup

“…A major area for clot formation was identified close to the blood inlet in the venous part inside the devices. However, thrombus formation did not correlate with ECMO support time, nor any patient characteristics .…”

“…Clots within membrane oxygenators (MOs) lead to an increase in blood flow resistance and reduced gas transfer capabilities . Device exchanges are required during ECMO therapy, despite systemic anticoagulation and surface coating . Lubnow et al showed that thrombus formation in MOs or pumps occurred in 35% of 265 ECMO cases in a retrospective analysis .…”

D-dimers Are a Predictor of Clot Volume Inside Membrane Oxygenators During Extracorporeal Membrane Oxygenation

“…After exchange in 11 patients, the levels of D-dimers decreased significantly within 2 days (day of exchange, 35 [34-35] mg/L; 2 days after exchange, 12 [8][9][10][11][12][13][14][15][16] mg/L, P = 0.004) ( Fig. 1).…”