Antithrombin level and circuit thrombosis during hemofiltration after cardiopulmonary bypass

Prevalence and Risk Factors for Thrombotic Complications Following Venovenous Extracorporeal Membrane Oxygenation: A CT Scan Study

OBJECTIVES

The aims of this study were to: 1) analyze the cannula-associated deep vein thrombosis frequency after venovenous extracorporeal membrane oxygenation using a CT scan and 2) identify the associated risk factors for cannula-associated deep vein thrombosis.

DESIGN

Retrospective observational analysis at a single center.

SETTING

Tertiary referral university teaching hospital.

PATIENTS

Patients under venovenous extracorporeal membrane oxygenation with a femorofemoral or femorojugular cannulation admitted for acute respiratory distress syndrome or primary graft dysfunction after pulmonary transplantation. CT scan was performed within 4 days after decannulation.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We included 105 of 228 patients screened. Bacterial pneumonia was the main indication of venovenous extracorporeal membrane oxygenation (46.7%). CT scans were performed at a median of 2 days (1-3 d) after decannulation. Cannula-associated deep vein thrombosis was found in 75 patients (71.4%) despite it having a mean activated partial thromboplastin time ratio of 1.60 ± 0.31. Femorofemoral cannulation induced femoral cannula-associated deep vein thrombosis more frequently than femorojugular cannulation (69.2% vs 63.1%, respectively; p = 0.04). Seventeen of the 105 patients (16.2%) had a pulmonary embolism. Multivariate logistic regression analysis showed that higher the percentage of thrombocytopenia less than 100 G/L during extracorporeal membrane oxygenation period, lower the risk for developing cannula-associated deep vein thrombosis (hazard ratio, 0.98; 95% CI, 0.98-1.00; p = 0.02).

CONCLUSIONS

Cannula-associated deep vein thrombosis after venovenous extracorporeal membrane oxygenation is a frequent complication. This plead for a systematic vascular axis imaging after venovenous extracorporeal membrane oxygenation. Thrombocytopenia is associated with a reduction in the occurrence of thrombotic events.

Response patterns of routinely measured inflammatory and coagulatory parameters in sepsis

Background

Sepsis is characterized by a pro-inflammatory and pro-coagulatory shift which can induce life-threatening complications. Close monitoring and risk stratification of sepsis patients is crucial for proper treatment and consequently patient outcome. Therefore, this study focuses on the response patterns of inflammatory and coagulatory parameters used in clinical routines to estimate the course of sepsis.

Methods

A total of 1,110 patients diagnosed with sepsis were retrospectively analyzed to identify response patterns for risk stratification of routine parameters measured at the peak level of C-reactive protein. Cluster analysis was used and the differences in the patient characteristics and 28-day survival were assessed. Cox proportional hazards regression model for survival stratified by the clusters was performed.

Results

The analyses revealed the parameters to have five distinct response patterns. These clusters reflect the etiology as well as the course of sepsis associated with different mortalities. Here, impairment of the liver plays a crucial role in the ability to appropriately respond to sepsis. Of the routinely measured parameters, C-reactive protein and antithrombin seem to be unspecific for stratification of septic patients. Adjusted for the individual clusters, survival was associated with an increase in fibrinogen (p = 0.0042), platelets (p = 0.0003) and PT (p = 0.001) as well as a decrease in leukocytes (p = 0.034).

Conclusions

This study reveals that patients have distinct response patterns of inflammatory and coagulatory parameters depending on disease etiology. These patterns are associated with different mortalities although the patients have similar levels of C-reactive protein. Independently of the type of response, good coagulatory capacity seems to be crucial for patient survival.

Thromboprophylaxis in Extracorporeal Circuits: Current Pharmacological Strategies and Future Directions

The development of extracorporeal devices for organ support has been a part of medical history and progression since the late 1900s. These types of technology are primarily used and developed in the field of critical care medicine. Unfractionated heparin, discovered in 1916, has really been the only consistent form of thromboprophylaxis for attenuating or even preventing the blood-biomaterial reaction that occurs when such technologies are initiated. The advent of regional anticoagulation for procedures such as continuous renal replacement therapy and plasmapheresis have certainly removed the risks of systemic heparinization and heparin effect, but the challenges of the blood-biomaterial reaction and downstream effects remain. In addition, regional anticoagulation cannot realistically be applied in a system such as extracorporeal membrane oxygenation because of the high blood flow rates needed to support the patient. More recently, advances in the technology itself have resulted in smaller, more compact extracorporeal life support (ECLS) systems that can-at certain times and in certain patients-run without any form of anticoagulation. However, the majority of patients on ECLS systems require some type of systemic anticoagulation; therefore, the risks of bleeding and thrombosis persist, the most devastating of which is intracranial hemorrhage. We provide a concise overview of the primary and alternate agents and monitoring used for thromboprophylaxis during use of ECLS. In addition, we explore the potential for further biomaterial and technologic developments and what they could provide when applied in the clinical arena.

Early graft thrombosis due to antithrombin III deficiency following CABG

The serine protease inhibitor antithrombin III (AT-III), an α2-globulin synthesized in the liver and endothelial cells, is the principal in vivo inhibitor of blood coagulation inactivating mainly thrombin. AT-III deficiency presents a rare hereditary or acquired disorder that most often comes to light when a patient suffers recurrent venous thrombosis and pulmonary embolism. Triggers for the onset of the thrombosis include various mechanisms such as pregnancy, delivery, surgery, trauma, and contraceptive pill use. Decreased response to heparin may be the first sign of AT-III deficiency. Since heparin is a conditio sine qua non for cardiopulmonary bypass, rapid consumption of AT-III promoted by heparin may lead to systemic thrombosis. The effect of heparin on graft patency after CABG in patients with AT-III deficiency, particularly with respect to early graft thrombosis, has not been fully investigated. The early detection and timely treatment of this disorder may impact perioperative morbidity. We present a case of simultaneous thrombosis of three venous grafts after elective coronary artery bypass surgery in a patient with AT-III deficiency.