{"id":730,"date":"2019-09-17T16:59:11","date_gmt":"2019-09-17T16:59:11","guid":{"rendered":"https:\/\/medicosnext.com\/?p=730"},"modified":"2019-09-17T17:05:45","modified_gmt":"2019-09-17T17:05:45","slug":"why-is-pt-inr-monitoring-so-important-challenging","status":"publish","type":"post","link":"https:\/\/medicosnext.com\/?p=730","title":{"rendered":"Why is PT\/INR monitoring so important & challenging?"},"content":{"rendered":"Namoti Nembang in conversation with Dr. Raamesh Koirala, cardiac surgeon at SGNHC<\/em><\/span>\n

An international normalized ratio (INR) test is critical for all people who are receiving warfarin treatment. Warfarin, a vitamin K antagonist, is one of the most widely prescribed anticoagulants. But it is difficult to manage, as it has both a narrow therapeutic index and numerous drug and dietary interactions. \u201cIts multiple interference with food, temperature, water, geographical location, disease states, and almost all kinds of medicines could cause great harm if not monitored and dosed correctly,\u201d says Dr. Raamesh Koirala, a cardiac surgeon at Sahid Gangalal National Heart Centre.
\nThe INR is a numeric value calculated from the prothrombin time (PT), a clotting assay result, and the International Sensitivity Index (ISI), which indicates sensitivity of the reagent used to perform the assay. One of the major challenges with warfarin is maintaining the patient\u2019s INR within the predetermined therapeutic range. It can neither be too high nor too low. Therefore, regular INR monitoring is a must to safeguard patients on anticoagulation therapy. \u201cMany fatalities may occur if they don\u2019t check their INR. There is an increased risk of bleeding if the INR is too high, and there is a risk of blood clotting if it\u2019s too low. The high doses can make people bleed from head, stomach, while brushing, coughing, and in cases of women, menstruation will not stop.\u201d
\nWarfarin will slow down the process of blood clotting. \u201cBut, as it is made from plant extracts, there are many vegetables like cabbage, kale, broccoli, spinach, and lettuce that we eat daily that will slow down the effect of warfarin. Therefore, eating a lot of food rich in vitamin K can lower the PT and INR, making warfarin less effective and potentially increasing the risk of blood clots,\u201d says Dr. Koirala.
\n\u201cIts effect is so rampant. It\u2019s really difficult to say what not to eat to patients. We usually tell them to eat what they normally do. To eat a consistent and balance diet and keep doing their INR test,\u201d the doctor adds. \u201cThe test is so sensitive, and it is difficult to get an accurate result from the labs and reagents, so a lot of people have died due to this.\u201d Therefore, frequent INR monitoring is the only way to maintain a balance between preventing clots and avoiding the risks of bleeding.
\nThere are two classes of antithrombotic drugs: anticoagulants and antiplatelet drugs. Both work to prevent clots in blood vessels but affect different blood clotting processes. Anticoagulants slow down clotting, thereby reducing fibrin formation and preventing clots from forming and growing in your heart, veins, or arteries, while antiplatelet agents prevent platelets from clumping and also prevent clots from forming and growing.<\/p>\n

<\/i>\n\t\t\tAnticoagulation Therapy People who are at risk of blood clotting are placed on anticoagulants. The most common indications for anticoagulation treatment are atrial fibrillation (AF), heart valve replacement, and venous thromboembolism. Examples are warfarin, aspirin, heparin, dabigatran, apixaban, and rivoraxaban. \u201cDabigatran is one of the new oral anticoagulants (non-warfarin drug) that doesn\u2019t require patients to undergo periodic INR monitoring. But, it hasn\u2019t been experimented on humans whose valves have been changed yet, as it is very dangerous,\u201d informs Dr. Koirala. Warfarin is usually prescribed to treat a blood clot for 3-6 months. \u201cIf a person with a tissue valve doesn\u2019t have any other indication for anticoagulation, then we will put him on warfarin for 3 months, and then prescribe him aspirin.\u201d But, for an irregular heartbeat or some heart valve problems, warfarin is prescribed indefinitely.\n\t\t\t<\/div><\/div>\n

Can PT\/INR confirm that one is 100 % risk free?<\/strong><\/p>\n

\u2022 An INR of 1 is normal and is found in people who are not on warfarin.
\n\u2022 An INR of 2 means that your blood takes twice as long to clot than a normal person. It doesn\u2019t guarantee that it won\u2019t clot. It may clot, but the risk is low.
\n\u2022 An INR of 3 means that your blood takes three times as long to clot as a normal person.<\/p>\n

\n

There are two classes of antithrombotic drugs: anticoagulants and antiplatelet drugs. Both work to prevent clots in blood vessels but affect different blood clotting processes.<\/p>\n<\/blockquote>\n

\"\"<\/p>\n

The optimal INR target range is 2.0-3.0, but it depends on the indications for anticoagulation. \u201cThough we follow the guidelines of American College of Cardiology\/American Heart Association, we have a tendency to be satisfied with a bit low INR value,\u201d says Dr. Koirala.<\/span><\/p>\n

\u2022 For micro valves or mechanical heart valves: our target INR range is 2.5-3.5<\/span>
\n\u2022 For aortic valves: our target INR range is 2-3 <\/span>
\n\u2022 For atrial fibrillation: our target INR range is 2-2.5 or 2-3<\/span><\/p>\n

Warfarin dose adjustment<\/strong><\/p>\n

If a person\u2019s INR is within a desired range, a patient has to check his or her INR every three to four weeks. If the report is not within the desired range, he or she needs to readjust the dose of drug to keep the INR readings as close to the target as possible. For that, they need to either check their INR every day, or get admitted to the hospital, informs Dr. Koirala.
\nAccording to Dr. Koirala, people with atrial fibrillation (AF) are those in most need of warfarin. But, in Nepal, the maximum number of people receiving warfarin are those with mechanical valves. \u201cIt is not possible to give warfarin to people with AF, because the number is too big. Also, the chances of blood clotting are low for AF, while people with mechanical valves are at highest risk for clotting. So, they are in need of warfarin the most.\u201d<\/p>\n

Our Effort<\/strong><\/p>\n

Our Effort is a non-profit organization running under the direct support of Dr. Raamesh Raj Koirala and Dr. Anil Acharya to help people requiring constant monitoring of INR managed anticoagulant therapy.
\nFounded on Kartik 13, 2068, Our Effort is currently running the PT\/INR mobile clinic with over 2000 beneficiaries directly. It is registered in Jhapa district and is financed by Dr. Raamesh Raj Koirala and supported by Dr. Anil Acharya and other doctors, while some fund is generated from French donors who want to help the needy patients. \u201cSome of my friends in France were sponsoring valves to 12-13 needy patients at the Sahid Gangalal National Heart Centre(SGNHC) annually for many years.When they asked me for a way to support the poor patients in the hospital, I gave them the names and they paid for their surgeries,\u201d says Dr. Koirala.
\n\u201cLater, when the government decided to give free valves to those who couldn\u2019t afford it, we thought of a way to make best use of the fund. So, I proposed to them to invest some money to buy INR test machines for people residing outside the valley. So, with their support and some of my investment Our Effort\u2019got started.
\nIt was founded with the desire to help people outside the valley do the INR test without having to travel to Kathmandu. \u201cBefore, we asked the patients to come to Kathmandu every three months to do the INR test.\u201d
\nAccording to Dr. Koirala, out of 600-700 valve operations in SGNHC every year, around 300 people are enrolled in this program. Our Effort provides warfarin to 95 percent of patients with mechanical valves. The remaining 5 percent are people with tissue valve and AF, he adds.
\nThe organization charges nominal fee from patients who purchase the strips for the test and for the medicines that they receive. There are four people involved in field activity of the clinic, along with four people in the technical department making all the necessary arrangements for the smooth operation of the clinic.
\nCurrently, the entire focus of Our Effort has been in anticoagulant therapy service through the PT\/INR mobile clinic. Its main concern is to provide convenient and easily available service to patients. There are currently 14 stations across the country.<\/p>\n

Bibliography<\/strong><\/span><\/p>\n

1. Pibarot, Philippe, and Jean G Dumesnil. \u201cProsthetic Heart Valves.\u201d Circulation, American Heart Association, 24 Feb. 2009, www.ahajournals.org\/doi\/10.1161\/CIRCULATIONAHA.108.778886.<\/span>
\n2. Kimmel, Stephen E. \u201cWarfarin therapy: in need of improvement after all these years.\u201d US National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, www.ncbi.nlm.nih.gov\/pmc\/articles\/PMC2855533\/<\/span>
\n3. \u201cA Patient\u2019s Guide to Taking Warfarin.\u201d American Heart Association, www.heart.org\/en\/health-topics\/arrhythmia\/prevention–treatment-of-arrhythmia\/a-patients-guide-to-taking-warfarin<\/span>
\n4. Katie T. Blissit, Mackenzie L. Mullenix, and Kevin G. Brittain, \u201cEvaluation of Time in Therapeutic Range on Warfarin Therapy Between Face-to-Face and Telephone Follow-Up in a VA Medical Center.\u201d US National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, 1 Oct 2014, www.ncbi.nlm.nih.gov\/pmc\/articles\/PMC6005418\/.<\/span>
\n5. \u201cAntithrombotic Therapy.\u201d Antithrombotic Society of HematologyTherapy, www.hematology.org\/About\/History\/50-Years\/1523.aspx.<\/span>
\n6. Floyd, Christopher N and Albert Ferro. \u201cIndications for anticoagulant and antiplatelet combined therapy.\u201d BMJ, BMJ Publishing Group Ltd., 5 Oct 2017, www.bmj.com\/content\/359\/bmj.j3782.full<\/span>
\n7. \u201cAnticoagulant and Antiplatelet Drugs.\u201d Healthline, Healthline Media, www.healthline.com\/health\/anticoagulant-and-antiplatelet-drugs#what-they-do<\/span>
\n8. Han, Haewook. \u201cThe Importance of Vitamin K Monitoring With Warfarin (Coumadin) Use in Chronic Kidney Disease Patients.\u201d Journal of Renal Nutrition, Elsevier , www.jrnjournal.org\/article\/S1051-2276(14)00190-3\/pdf.<\/span>
\n9. Kuruvilla, Mariamma, and Cheryle Gurk-Turner. \u201cA Review of Warfarin Dosing and Monitoring.\u201d Baylor University. Medical Center Proceedings , Baylor Health Care System, July 2001, www.ncbi.nlm.nih.gov\/pmc\/articles\/PMC1305837\/.<\/span>
\n10. Nishimura, Rick A., et al. \u201cTable11.\u201d JACC , Journal of the American College of Cardiology, July 2017, www.onlinejacc.org\/content\/70\/2\/252\/T11.<\/span>
\n11. Kinman, Tricia. \u201cAbout Anticoagulant and Antiplatelet Drugs.\u201d Healthline, Healthline Media, 1 Dec. 2016, www.healthline.com\/health\/anticoagulant-and-antiplatelet-drugs#what-they-do.<\/span>
\n12. \u201cUse of INR for Monitoring Warfarin Treatment.\u201d Use of INR for Monitoring Warfarin Treatment – Best Tests Issue November 2010, Nov. 2010, bpac.org.nz\/BT\/2010\/November\/inr.aspx.<\/span>
\n13. \u201cProthrombin Time and International Normalized Ratio (PT\/INR).\u201d Patient Education on Blood, Urine, and Other Lab Tests, American Association for Clinical Chemistry, 10 July 2010, labtestsonline.org\/tests\/prothrombin-time-and-international-normalized-ratio-ptinr.<\/span>
\n14. Kamthornthanakarn, Itthidet, and Rungroj Krittayaphong. \u201cOptimal INR Level for Warfarin Therapy after Mechanical Mitral Valve Replacement.\u201d BMC Cardiovascular Disorders, BioMed Central, 25 Apr. 2019, www.ncbi.nlm.nih.gov\/pmc\/articles\/PMC6482495\/.<\/span><\/p>\n","protected":false},"excerpt":{"rendered":"

Namoti Nembang in conversation with Dr. Raamesh Koirala, cardiac surgeon at SGNHC An international normalized ratio (INR) test is critical for all people who are receiving warfarin treatment. Warfarin, a vitamin K antagonist, is one of the most widely prescribed anticoagulants. But it is difficult to manage, as it has both a narrow therapeutic index …<\/p>\n","protected":false},"author":5,"featured_media":732,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"advanced_seo_description":"","jetpack_seo_html_title":"","jetpack_seo_noindex":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":false,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[37],"tags":[70,72,71,74,73],"class_list":["post-730","post","type-post","status-publish","format-standard","has-post-thumbnail","","category-health","tag-antagonist","tag-anticoagulation","tag-prothrombin","tag-pt-inr","tag-warfarin"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"https:\/\/i0.wp.com\/medicosnext.com\/wp-content\/uploads\/2019\/09\/laboratory-313861-e1568739527584.jpg?fit=1000%2C669&ssl=1","jetpack_likes_enabled":true,"jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/medicosnext.com\/index.php?rest_route=\/wp\/v2\/posts\/730","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/medicosnext.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/medicosnext.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/medicosnext.com\/index.php?rest_route=\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"https:\/\/medicosnext.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=730"}],"version-history":[{"count":0,"href":"https:\/\/medicosnext.com\/index.php?rest_route=\/wp\/v2\/posts\/730\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/medicosnext.com\/index.php?rest_route=\/wp\/v2\/media\/732"}],"wp:attachment":[{"href":"https:\/\/medicosnext.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=730"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/medicosnext.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=730"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/medicosnext.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=730"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}