Abstract Number: PB0139
Meeting: ISTH 2021 Congress
Background: Continuous renal replacement therapy (CRRT) is an important modality in critical care that utilizes a closed blood circuit with a hollow fiber membrane hemofilter (Figure 2A). CRRT circuit failure is a costly complication with an unclear mechanism, prominently observed during the coronavirus disease 2019 (COVID-19) pandemic.
Aims: In this retrospective case series, we study the basis of circuit failure, particularly in the setting of COVID-19, via histopathologic examination of hemofilters after use in CRRT circuits.
Methods: Study patients were identified from critically ill patients, admitted to Weill Cornell Medical Center between April and June 2020, who had acute kidney injury requiring CRRT. Circuit failure was defined as the inability of the circuit to provide the prescribed continuous blood flow rate to the patient, necessitating a hemofilter change in advance of its 72-hour lifespan. Hemofilters from failed and functional circuits were formalin-fixed, sectioned and evaluated with histopathologic stains and immunohistochemistry (IHC). Chart review was completed in accordance with IRB-approved protocols.
Results: Circuit failure occurred in 4 out of 6 study patients. Two patients with severe COVID-19 experienced circuit failure despite anticoagulation with argatroban or regional citrate (Table 1). All hemofilters displayed the accumulation of dense, platelet-rich aggregates at the arterial ends (Figure 2B-2C), with a greater volume found in failed hemofilters. The hollow fiber membranes in hemofilters used for patients with severe COVID-19 displayed fibrinogen localized along the blood-facing lumens by IHC (Figure 2D). While hemofilters used for patients with COVID-19 exhibited such luminal fibrinogen staining regardless of circuit function, for patients without COVID-19 this was seen only in failed hemofilters.
|Case #||Medical History||Reason for Admission||SARS-CoV-2 RT-PCR||Circuit Function at Hemofilter Collection||Anticoagulation at Hemofilter Collection||Neutrophil Count
|D-dimer (ng/ml)||Fibrinogen (mg/dl)|
|1||67-year-old woman with ESRD, vasculitis||COVID-19 respiratory failure||Positive||Functional||Unfractionated heparin
|2||48-year-old man with DM2, atrial flutter||COVID-19 respiratory failure||Positive||Failed||Argatroban
|3||81-year-old-man with ESRD, HTN, DM2||COVID-19 respiratory failure||Positive||Failed||Regional citrate||14.9||39||5162||283|
|4||74-year-old woman with CAD, ESRD, DM2||Myocardial infarction and CABG||Negative||Functional||None||10.6||174||532||162|
|5||63-year-old man with heart failure, CKD||Acute on chronic heart failure||Negative||Failed||None||6.8||157||2813||164|
|6||61-year-old man with alcohol-related cirrhosis||Orthotopic liver transplant||Negative||Failed||None||8.7||23||9939||122|
Conclusions: Fibrinogen adsorption on biocompatible hemofilter surfaces exposed to patient blood appears to be an initial event preceding CRRT circuit failure. With COVID-19, this adsorption occurs despite intensified anticoagulation. Further mechanistic study of hemofilter failure may facilitate direct therapeutic strategies to prevent this complication.
To cite this abstract in AMA style:Choi D, Liu F, Borczuk A. Fibrinogen Adsorption on Hemofilter Membranes Associates with Severe COVID-19 and Renal Replacement Therapy Circuit Failure [abstract]. Res Pract Thromb Haemost. 2021; 5 (Suppl 2). https://abstracts.isth.org/abstract/fibrinogen-adsorption-on-hemofilter-membranes-associates-with-severe-covid-19-and-renal-replacement-therapy-circuit-failure/. Accessed December 5, 2021.
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