thrombosis prevention

File:Flow chart of clot prevention.jpgThe development of blood clots can be interrupted and prevented by the use of medication, changing risk factors, and other interventions. Some risk factors can be modified. These would be losing weight, increasing exercise, and the cessation of oral contraceptives. Moving during periods of travel is a modifiable behavior. Preventing blood clots includes medications that interrupt the complex clotting cascade and changing the proteins needed for clotting. Antiplatelet drugs also have an effect in preventing the formation of clots.{{cite journal |last1=Diep |first1=R |last2=Garcia |first2=D |title=Does aspirin prevent venous thromboembolism? |journal=Hematology. American Society of Hematology Education Program |date=December 2020 |volume=2020 |issue=1 |pages=634–41 |doi=10.1182/hematology.2020000150 |pmid=33275727 |url=https://ashpublications.org/hematology/article/2020/1/634/474338/Does-aspirin-prevent-venous-thromboembolism |access-date=14 February 2025|pmc=7727539 }}

Thrombosis prophylaxis is not only used for the prevention of deep vein thrombosis but can be initiated for the prevention of the formation of blood clots in other organs and circumstances unrelated to deep vein thrombosis:{{citation needed|date=February 2021}}

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• cerebral complications
• abortion
• ectopic pregnancy
• molar pregnancy
• pregnancy
• childbirth and the puerperium
• coronary
• portal vein thrombosis
• intracranial, nonpyogenic
• intraspinal, nonpyogenic
• mesenteric
• pulmonary{{cite web | title = ICD-10 Version:2016 |publisher= International Statistical Classification of Diseases and Related Health Problems 10th Revision | url = http://apps.who.int/classifications/icd10/browse/2016/en#/I80 | access-date = December 18, 2016 }}{{cite book | last = Leveno | first = Kenneth | name-list-style = vanc | title = Williams manual of pregnancy complications | publisher = McGraw-Hill Medical | location = New York | year = 2013 | isbn = 978-0071765626 }}

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The risk of developing deep vein thrombosis, or pulmonary embolism is different than the total risk of the formation of blood clots. This is due to the observation that not all blood clots form in the lower legs. Most hospitalized medical patients have at least 1 risk factor for thrombosis that progresses to thromboembolism and this risk persists weeks after discharge. Those who remain undiagnosed and not treated prophylactically have a 26% chance of developing a fatal embolism. Another 26% develop another embolism. Between 5% and 10% of all in-hospital deaths are due to pulmonary embolism (as a consequence of thrombosis). Estimates of the incidence of pulmonary embolism in the US is 0.1% persons/year. Hospital admissions in the US for pulmonary embolism are 200,000 to 300,000 yearly.{{cite journal | vauthors = Kafeza M, Shalhoub J, Salooja N, Bingham L, Spagou K, Davies AH | s2cid = 13759574 | title = A systematic review of clinical prediction scores for deep vein thrombosis | journal = Phlebology | volume = 32 | issue = 8 | pages = 516–531 | date = September 2017 | pmid = 27885107 | doi = 10.1177/0268355516678729 | hdl = 10044/1/41102 | hdl-access = free }} Thrombosis that develops into DVT will affect 900,000 people and kill up to 100,000 in the US. On average 28,726 hospitalized adults aged 18 and older with a VTE blood clot diagnosis die each year.{{cite web | title = Venous Thromboembolism (VTE) | work = National Center on Birth Defects and Developmental Disabilities | url = https://www.cdc.gov/ncbddd/aboutus/annualreport2012/documents/ar2012-vte-printversion.pdf | archive-url = https://web.archive.org/web/20181023195721/https://www.cdc.gov/ncbddd/aboutus/annualreport2012/documents/ar2012-vte-printversion.pdf | archive-date = October 23, 2018 }} {{PD-notice}} Risk of thrombosis is related to hospitalization. In 2005 the UK the Parliamentary Health Select Committee determined the annual rate of death due to thrombosis was 25,000 with at least 50% being hospital-acquired.{{cite journal | vauthors = Hunt BJ | title = Awareness and politics of venous thromboembolism in the United kingdom | journal = Arteriosclerosis, Thrombosis, and Vascular Biology | volume = 28 | issue = 3 | pages = 398–9 | date = March 2008 | pmid = 18296598 | doi = 10.1161/ATVBAHA.108.162586 | doi-access = free }}

The type of surgery performed prior to the formation of blood clots influences the risk.

Without prophylactic interventions, the calculated incidence of clot formation in the lower leg veins after surgery is:

• 22% for neurosurgery
• 26% for abdominal surgery
• 45% for 60% in orthopedic surgery
• 14% for gynecologic surgery{{cite book | last = Newman | first = Mark | name-list-style = vanc | title = Perioperative medicine : managing for outcome | url = https://archive.org/details/perioperativemed00mdma | url-access = limited | publisher = Saunders Elsevier | location = Philadelphia | year = 2008 | isbn = 978-1437721263 |pages = [https://archive.org/details/perioperativemed00mdma/page/n45 29]–34 }}

As the population of the US ages, the development of blood clots is becoming more common.{{cite web | first1 = Peter K. | last1 = Henke | first2 = Mark H. | last2 = Meissner | first3 = Thomas W. | last3 = Wakefield | name-list-style = vanc | title = Chapter 2: Risk Factors for Venous Thrombosis |publisher= American Venous Forum

| url = http://www.veinforum.org/uploadDocs/1/Chapter-2---Risk-Factors-for-Venous-Thrombosis.pdf | archive-url = https://web.archive.org/web/20160927035005/http://www.veinforum.org/uploadDocs/1/Chapter-2---Risk-Factors-for-Venous-Thrombosis.pdf | archive-date = September 27, 2016 | access-date = December 24, 2016 }}

Some risk factors for developing blood clots are considered higher than others. One scoring system analyzes the probability of clot formation by assigning a point value system to significant risk factors.{{cite book | last = Hoffman | first = Barbara | name-list-style = vanc | title = Williams gynecology | publisher = McGraw-Hill Medical | location = New York | year = 2012 | isbn = 978-0071716727 | pages = 960–968 }} The benefit of treating those who are at low risk of developing blood clots may not outweigh the higher risks of significant bleeding.{{cite journal | vauthors = Cameron AC, McCallum L, Gardiner T, Darroch C, Walters MR, Oldroyd KG | title = Impact of treatment algorithms on the prescribing of antithrombotic therapy in patients with suspected acute coronary syndrome – a prospective audit | journal = British Journal of Clinical Pharmacology | volume = 80 | issue = 5 | pages = 1176–1184 | date = November 2015 | pmid = 26147691 | pmc = 4631190 | doi = 10.1111/bcp.12714 }}

{{collapse top|title=Risk factors for developing blood clots that are assessed before treatments

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Developing blood clots is more probable after the first episode. Risk assessment and intervention for those with one or more episodes of deep vein thrombosis or blood clots in the veins utilize the Well's test. It has been inconsistently modified by several publishers with the results listed below:{{cite journal | vauthors = Modi S, Deisler R, Gozel K, Reicks P, Irwin E, Brunsvold M, Banton K, Beilman GJ | display-authors = 6 | title = Wells criteria for DVT is a reliable clinical tool to assess the risk of deep venous thrombosis in trauma patients | journal = World Journal of Emergency Surgery | volume = 11 | issue = 1 | pages = 24 | year = 2016 | pmid = 27279896 | pmc = 4898382 | doi = 10.1186/s13017-016-0078-1 | doi-access = free }}

Scoring:

• less than 2 points – low risk (3%)
• 2–6 points moderate risk (17%)
• > 6 points high risk (75%)

The Centers for Disease Control and Prevention have issued general guidelines describing the interventions that can be taken to reduce the risk of the formation of blood clots:

{{Quote box|width=75em|align=center|quote=The Centers for Disease Control and Prevention recommend the following:

• Move around as soon as possible after being confined to bed, such as after surgery, illness, or injury.
• If you're at risk for DVT, talk to your doctor about:
• Graduated compression stockings (sometimes called "medical compression stockings")
• Medication (anticoagulants) to prevent DVT.
• When sitting for long periods, such as when traveling for more than four hours:
• Get up and walk around every 2 to 3 hours.
• Exercise your legs while you're sitting by:
• Raising and lowering your heels while keeping your toes on the floor
• Raising and lowering your toes while keeping your heels on the floor
• Tightening and releasing your leg muscles
• Wear loose-fitting clothes.
• You can reduce your risk by maintaining a healthy weight, avoiding a sedentary lifestyle, and following your doctor's recommendations based on your individual risk factors.{{cite web | title = Venous Thromboembolism (Blood Clots) Facts| publisher= Division of Blood Disorders National Center on Birth Defects and Developmental Disabilities, Centers for Disease Control and Prevention | date= 24 February 2016

| url = https://www.cdc.gov/ncbddd/dvt/facts.html | access-date = 2016-07-19}} {{PD-notice}}

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Seat-edge pressure from the seat on an airplane on the popliteal area may contribute to vessel wall damage as well as venous stasis. Coagulation activation may result from an interaction between cabin conditions (such as hypobaric hypoxia) and individual risk factors for the formation of blood clots. Studies of the pathophysiologic mechanisms for the increased risk of venous thromboembolism or VTE after long-distance travel have not produced consistent results, but venous stasis appears to play a major role; other factors specific to air travel may increase coagulation activation, particularly in passengers with individual risk factors for VTE.{{cite web| title = Deep Vein Thrombosis & Pulmonary Embolism, Chapter 2, Travelers' Health |publisher= CDC| url = https://wwwnc.cdc.gov/travel/yellowbook/2016/the-pre-travel-consultation/deep-vein-thrombosis-pulmonary-embolism| access-date = December 25, 2016 }}{{PD-notice}}

Mechanical compression devices are used to prevent thrombosis and are beneficial enough to be used by patients at low to moderate risk. The use of fitted intermittent pneumatic compression devices before, during, and after procedures is used in inpatient settings. It consists of an air pump and inflatable auxiliary compartments that sequentially inflate and deflate to provide an external 'pump' that returns venous blood toward the heart.{{cite journal | vauthors = Gould MK, Garcia DA, Wren SM, Karanicolas PJ, Arcelus JI, Heit JA, Samama CM | title = Prevention of VTE in nonorthopedic surgical patients: Antithrombotic Therapy and Prevention of Thrombosis 9th ed, American College of Chest Physicians Evidence-Based Clinical Practice Guidelines | journal = Chest | volume = 141 | issue = 2 Suppl | pages = e227S–e277S | date = February 2012 | pmid = 22315263 | pmc = 3278061 | doi = 10.1378/chest.11-2297 }} The use of intermittent pneumatic compression is common. These devices are also placed on a surgical patient in the operating room (the intra-surgical period) and remain on the person while recovering from the surgery.

The application of antiembolism stockings can be used to prevent thrombosis. The correct use and properly fitted graded compression stockings can reduce the rate of thrombosis by 50%.{{rp|745–46}} Contraindications for the use of antiembolism stockings include the presence of advanced peripheral and obstructive arterial disease, septic phlebitis, heart failure, open wounds, dermatitis and peripheral neuropathy.{{cite web |publisher=Sigvaris |first=Robert |last=Stemmer | name-list-style = vanc |title=Compression Bulletin 24 |url=http://www.sigvariscares.com/ftp/CB/COMPBUL24.pdf |archive-url=https://web.archive.org/web/20150620140127/http://www.sigvariscares.com/ftp/CB/COMPBUL24.pdf |url-status=dead |archive-date=June 20, 2015 |page=2 |date=February 2013 |access-date=December 21, 2016 }} Differences between the use of thigh-high compression stockings and shorter types to prevent blood clots exist, but remain inconsistent.

There has been some success in preventing blood clots through an early risk assessment upon hospital admission, a strategy recognized by the Centers for Disease Control and Prevention. Hospitals that have participated in this effort to reduce the incidence of thrombosis found that rates of DVT decreased in some instances. Some hospitals developed a mandatory assessment quantifying the risk of developing blood clots and a plan of care developed from the results. The person's risk for developing blood clots is entered into their record, 'following' them through their treatment regime. If the hospital stay exceeds three days, the person will be reassessed for risk. Clinicians can then apply protocols for prevention based on best clinical practices.{{cite web | title = The 2015 Healthcare-Associated Venous Thromboembolism Prevention Challenge Champions |publisher= CDC | url = https://www.cdc.gov/ncbddd/dvt/ha-vte-challenge.html

| access-date = December 28, 2016 | date = December 7, 2016 }}{{PD-notice}}{{cite journal | vauthors = Minami CA, Yang AD, Ju M, Culver E, Seifert K, Kreutzer L, Halverson T, O'Leary KJ, Bilimoria KY | display-authors = 6 | title = Evaluation of an institutional project to improve venous thromboembolism prevention | journal = Journal of Hospital Medicine | volume = 11 | pages = S29–S37 | date = December 2016 | issue = Suppl 2 | pmid = 27925424 | doi = 10.1002/jhm.2663 | doi-access = free }}

File:Poplitial vein.jpg

Immobility is a significant risk factor in the development of thrombosis.{{cite web | url = http://www.thrombosisuk.org/awareness-questions.php | access-date = December 29, 2016 | publisher = Thrombosis UK | title = Frequently Asked questions | date = 2015 | archive-date = June 12, 2016 | archive-url = https://web.archive.org/web/20160612020046/http://www.thrombosisuk.org/awareness-questions.php | url-status = dead }}{{cite book | last = Potter | first = Patricia | name-list-style = vanc | title = Fundamentals of nursing | publisher = Mosby Elsevier | location = St. Louis, Mo | year = 2013 | isbn = 978-0323079334 | page = 1149 }} Immediate post-surgical interventions, such as out of bed orders (OOB), are typically ordered by the physician to prevent thrombosis. These orders, typically delegated to a nurse, but may include the participation of a physical therapist and others trained to perform the intervention, are to perform range of motion (ROM) activities that include: muscle contractions of the lower legs for those who are very weak, moving the feet, wiggling the toes, bending the knees, raise and lower the legs. In addition, changes in positioning prevent immobility and shift areas of venous stasis. If the person is too weak to perform these preventative activities, hospital personnel will perform these movements independently. Exercise of the lower extremities is a post-operative method of prophylaxis. Nursing personnel will often perform a range of motion exercises and encourage frequent moving of the legs, feet, and ankles. Frequent positioning changes and adequate fluid intake. After a surgical procedure, ambulation as soon as possible is prophylactic in preventing the formation of blood clots.

Early ambulation also prevents venous stasis and physicians order OOB activities on the same day of surgery. This is accomplished in increments. The progression of increasing mobility proceeds by: raising the head of the bed, sitting up in bed, moving to the edge of the bed, dangling the legs off the bed, and then ambulating to a closed chair.

Patient education and compliance reduce the risk of developing blood clots. These exercises and the use of equipment and follow-up by clinicians reduce the risk of developing blood clots.

If a blood clot has already formed in the deep veins of the leg, early movement out of bed is usually prescribed, except in some severe cases of deep vein thrombosis or in people who have phlegmasia cerulea dolens. The treatment to prevent blood with physical intervention (e.g., sequential compression device) is contraindicated.{{citation needed|date=February 2021}}

Thromboprophylaxis, such as anticoagulants or perioperative heparin, is effective for hospitalized patients at risk for VTE.{{Cite journal|last1=Kahn|first1=Susan R.|last2=Morrison|first2=David R.|last3=Diendéré|first3=Gisèle|last4=Piché|first4=Alexandre|last5=Filion|first5=Kristian B.|last6=Klil-Drori|first6=Adi J.|last7=Douketis|first7=James D.|last8=Emed|first8=Jessica|last9=Roussin|first9=André|last10=Tagalakis|first10=Vicky|last11=Morris|first11=Martin|date=April 24, 2018|title=Interventions for implementation of thromboprophylaxis in hospitalized patients at risk for venous thromboembolism|journal=The Cochrane Database of Systematic Reviews|volume=2018|issue=4|pages=CD008201|doi=10.1002/14651858.CD008201.pub3|issn=1469-493X|pmc=6747554|pmid=29687454}} Additional risk factors such as obesity, disease, malignancies, long surgeries, and immobility may influence the prescribed dosage. Anticoagulant medications may prevent the formation of blood clots in people who are at high risk for their development. Treating blood clots that have already formed is managed by the use of anti-hemolytic ("clot busters"). Despite its effectiveness, the use of thromboprophylaxis remains under-utilized, though alerts (computer or human) in hospitals are associated with increased prescription and reductions in symptomatic VTE. The list below describes some of the more common medications used to prevent blood clots. Note that generally since blood clotting is inhibited, a side effect typically is increased bleeding, though it can be reversed by administering a medication that stops the bleeding or by discontinuation of the medication itself. Anti-coagulant administration is often given before the start of the operation. Medications that inhibit blood clot formation include:

{{collapse top|title=Medications used to prevent blood clots }}

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Adding heparin to the use of compression stockings may prevent thrombosis for those at higher risk.{{cite journal | vauthors = Zareba P, Wu C, Agzarian J, Rodriguez D, Kearon C | title = Meta-analysis of randomized trials comparing combined compression and anticoagulation with either modality alone for prevention of venous thromboembolism after surgery | journal = The British Journal of Surgery | volume = 101 | issue = 9 | pages = 1053–62 | date = August 2014 | pmid = 24916118 | doi = 10.1002/bjs.9527 | s2cid = 37373926 | doi-access = free }}

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The discontinuation of contraceptives also prevents blood clots.

The therapeutic effects of warfarin may be decreased by valerian. Chamomile can affect the action of anticoagulants. Dong quai, garlic, ginger, Ginkgo biloba, bilberry, and feverfew can increase bleeding time. These same herbal supplements taken with warfarin increased prothrombin time.

By containing significant content of vitamin K, some foods act as antagonists to antiplatelet and anticoagulant medications; these include green leafy vegetables, like spinach, legumes, and broccoli.

Preventing blood clots with medication is not considered safe in the following circumstances:

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• uncooperative patient
• recent childbirth
• gastrointestinal bleeding
• reproductive system
  bleeding
• genitourinary system
  bleeding
• hemorrhagic blood dyscrasias
• peptic ulcers
• alcohol use disorder
• infection
• eye surgery
• brain surgery
• spinal cord surgery
• recent intracranial hemorrhage{{rp|877}}

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An international registry and risk assessment calculator is being used to centralize data on post-surgical venous thrombosis and its prevention.{{cite web | title = Computerized Registry of Patients with Veneous Thromboembolism — RIETE Registry |publisher=S & H Medical Science Service| url = https://www.riete.org/info/estimate-calculator/index.php

| access-date = February 13, 2016 }} Hospitals are implementing a multidisciplinary approach to prevent of blood clots. This includes adequate assessment of the risks, follow-up on missed doses of medication, and instituting a 'patient-centered' approach endorsed by the Joint Commission.{{cite journal | vauthors = Streiff MB, Lau BD, Hobson DB, Kraus PS, Shermock KM, Shaffer DL, Popoola VO, Aboagye JK, Farrow NA, Horn PJ, Shihab HM, Pronovost PJ, Haut ER | display-authors = 6 | title = The Johns Hopkins Venous Thromboembolism Collaborative: Multidisciplinary team approach to achieve perfect prophylaxis | journal = Journal of Hospital Medicine | volume = 11 | pages = S8–S14 | date = December 2016 | issue = Suppl 2 | pmid = 27925423 | doi = 10.1002/jhm.2657 | doi-access = free }} Recommendations regarding the prevention of blood clots vary widely between clinicians and treatment facilities. Research continues to clarify these discrepancies. The metabolic state of hypercoagulability (the tendency to form blood clots) tests are being developed. These include the evaluation of the thrombin–antithrombin complexes (TAT), low levels of the anticoagulants ATIII and protein C, but these tests are not yet widely available.

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Category:Preventive medicine

Category:Diseases of veins, lymphatic vessels and lymph nodes

Category:Coagulopathies

Category:Hematology

Category:Antiplatelet drugs

Category:Aspirin

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Category:Salicylates

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