When Thrombus Meets Infection
By Eddie Korycka, MSN, RN, VA-BC
In the world of vascular access, few phenomena are as interconnected as the relationship between thrombus and infection. Both thrombus formation and infection are complications that, when occurring separately, can pose significant risks to the function of a vascular access device and the patient. However, when these two processes intertwine, they can create a dangerous interconnection that complicates diagnosis, treatment, and patient outcomes. Understanding this relationship and heading off the interplay between these two complications is essential to driving optimal outcomes for patients.
Thrombus Formation: A Brief Overview
The insertion of a vascular access device (VAD) can disrupt the normal endothelial lining of the blood vessel, leading to an increased risk of catheter related thrombosis (CRT) (1,2). This risk is particularly significant in the use of VADs because:
Endothelial Injury: The insertion and presence of a VAD can cause local trauma to the vessel wall, leading to endothelial injury. This injury recruits platelets and fibrin into the area which then promotes thrombus formation (2).
Stasis of Blood Flow: VADs can partially obstruct blood flow within the vessel, causing stasis, which further increases the likelihood of thrombus formation (2).
Hypercoagulability: Some patients with underlying conditions (such as cancer or coagulation disorders) may already be in a hypercoagulable state, increasing the risk of thrombosis when a VAD is inserted (2).
Device Material: Most polyurethane and silicone catheters are hydrophobic with irregular surfaces, making them prone to protein adsorption in the bloodstream. This triggers platelet and leukocyte adhesion, promoting thrombosis and thrombotic occlusion. Additionally, blood adherence forms a fibrin sheath around the catheter, trapping bacteria and increasing the risk of infection (1,7).
Infection: The Body’s Defense Gone Awry
Infections occur when harmful microorganisms such as bacteria, viruses, fungi, or parasites invade the body. The immune system responds by mounting a defense, which includes inflammation, fever, and the activation of white blood cells (3). While this immune response is crucial for eliminating the infection, it can also lead to complications if it becomes overactive or if the pathogens trigger a more severe response (3,4). Coagulation problems caused by infection, inflammation, or tissue damage can lead to conditions like disseminated intravascular coagulation (DIC). At the same time, immune system issues can also cause coagulation disorders and increase the risk of thrombotic complications (4).
The Intersection of Thrombus and Infection
The relationship between thrombus and infection is bidirectional—each can influence and exacerbate the other. Here’s how:
Infection-Induced Thrombosis:
Inflammatory Response: During an infection, the body’s inflammatory response can lead to endothelial injury, one of the components of Virchow’s Triad. Inflammation can cause the release of pro-inflammatory cytokines and other mediators that promote clot formation (4).
Direct Pathogen Effects: Some pathogens can directly induce thrombus formation. For example, bacteria such as Staphylococcus aureus can produce toxins that damage the endothelium and activate platelets, contributing to clot formation (4).
Sepsis and DIC: In severe infections like sepsis, the body’s response can be so overwhelming that it triggers disseminated intravascular coagulation (DIC), a condition where widespread clotting occurs throughout the body, leading to a high risk of thrombus formation (4).
Thrombosis-Related Infections:
Impaired Blood Flow: A thrombus can obstruct blood flow, leading to localized areas of poor circulation. This stagnant environment can be a breeding ground for bacteria, increasing the risk of infection (1,2).
Medical Devices: Thrombus formation on or around medical devices such as vascular access catheters can serve as a nidus for bacterial colonization, leading to catheter associated blood stream infections (CABSI) (1,7).
The Clinical Implications
The interplay between thrombus and infection has significant clinical implications:
Diagnosis: The presence of a thrombus in a patient with an active infection can complicate the diagnosis. For example, distinguishing between a simple infection and one complicated by DVT or PE can be challenging but is crucial for effective treatment (2,4).
Treatment: Treating patients with both a thrombus and an infection requires a multifaceted approach. Anticoagulants may be needed to manage the thrombus, while antibiotics or antivirals are required to address the infection. However, care must be taken to avoid potential complications, such as bleeding risks associated with anticoagulation in the presence of an active infection (4).
Prevention: Understanding the link between infection and thrombus formation underscores the importance of preventive measures, such as thromboprophylaxis in high-risk patients, early mobilization, and strict infection control practices, particularly in hospitalized patients.
MIMIX® technology made from hydrophilic hydrogel, rather than just a coating, shows significant improvements in thromboresistance. The material, a porous polyvinyl alcohol and polyacrylic acid hydrogel, repels protein adsorption and enhances strength and lubricity(1,5,6). In vitro studies have shown a 97% reduction in thrombus accumulation over polyurethane (1,5) and a 99.9% reduction in bacterial adhesion over polyurethane (6).
Conclusion
The relationship between thrombus and infection is a complex and dynamic one, with each condition potentially exacerbating the other. This interaction poses unique challenges in both the diagnosis and management of affected patients. As our understanding of this relationship deepens, it highlights the need for a comprehensive approach to patient care—one that addresses both the risks of thrombosis and infection simultaneously to improve outcomes and reduce complications. Consideration of catheter materials is essential to reducing both these risks. MIMIX technology from Access Vascular represents the latest innovation in catheter material and has demonstrated reductions in both thrombus and bacterial adhesion to the catheter surface.
By staying vigilant and employing a multidisciplinary approach, healthcare providers can better navigate this intricate interplay and enhance the safety and well-being of their patients.
References:
1. Moureau NL (2022) Integrative Review: Complications of Peripherally Inserted Central Catheters (PICC) and Midline Catheters with Economic Analysis of Potential Impact of Hydrophilic Catheter Material. Int J Nurs Health Care Res 5: 1347. DOI:10.29011/2688-9501.101347. Reduction of thrombus accumulation was evaluated using in vitro. Pre-clinical in vitro/in vivo evaluations do not necessarily predict clinical performance with respect to thrombus formation.
2. Wall, C., Moore, J., & Thachil, J. (2016). Catheter-related thrombosis: a practical approach. Journal of the Intensive Care Society, 17(2), 160-167
3. Nicholson LB. The immune system. Essays Biochem. 2016 Oct 31;60(3):275-301. doi: 10.1042/EBC20160017. PMID: 27784777; PMCID: PMC5091071.
4. Wilhelm G, Mertowska P, Mertowski S, Przysucha A, Strużyna J, Grywalska E, Torres K. The Crossroads of the Coagulation System and the Immune System: Interactions and Connections. Int J Mol Sci. 2023 Aug 8;24(16):12563. doi: 10.3390/ijms241612563. PMID: 37628744; PMCID: PMC10454528.
5. Mannarino MM, Bassett M, Donahue DT, Biggins JF. Novel high-strength thromboresistant poly (vinyl alcohol)-based hydrogel for vascular access applications. Journal of Biomaterials Science, Polymer Edition. 2020 Mar 23;31(5):601-21. Reduction of thrombus accumulation was evaluated using in vitro and in vivo models. Pre-clinical in vitro/in vivo evaluations do not necessarily predict clinical performance with respect to thrombus formation.
6. LeRoy, K. J., & Donahue, D. T. (2023). Results of A Bench Model Investigating Bacterial Adhesion on Novel Hydrophilic Biomaterial Catheter. Presented at AVA 2023 via e-poster. Reduction of thrombus accumulation was evaluated using in vitro. Pre-clinical in vitro/in vivo evaluations do not necessarily predict clinical performance with respect to thrombus formation.
7. Treter J, Macedo AJ. Catheters: a suitable surface for biofilm formation. Science against microbial pathogens: communicating current research and technological advances. 2011;2(3):835-42.