The Prevalence of Sub Optimal Anti Coagulation

Study Overview
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Brief Summary
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A study on warfarin administration to show whether noncompliance of the patient will affect our target (INR) during therapy or not beside its drug and dietary interactions. The study will show the prevalence of sub optimal anti coagulation among patients with prosthetic cardiac valves that will undergo warfarin therapy.

Detailed Description
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Besides the risk of infective endocarditis, thromboembolism from the foreign body structures of the prosthesis remains a major problem, which can be effectively reduced, but not inhibited by the use of oral anticoagulants in patients with prosthetic cardiac valves. Warfarin as a vitamin k antagonist is widely used to decrease risk of thromboembolism but need strict monitoring for INR to avoid warfarin failure or hemorrhage. It acts through inhibiting an enzyme called the vitamin K1 2,3 epoxide reductase complex, subunit1 (VKORC1). All patients with mechanical heart valves need the oral anticoagulation to keep the INR between 2.5:3.5 according to valve type, position and other comorbid conditions. However some patients need higher than expected doses of warfarin to get their (INR) into the target therapeutic range. Resistance to warfarin has been described as the inability to prolong the prothrombin time or raise the international normalized ratio (INR) into the therapeutic range when the drug is given at normally prescribed doses. Resistance is different than warfarin failure ,which is defined as a new thrombotic event despite a therapeutic prothrombin time and INR . The causes of warfarin resistance can be either acquired from high consumption of vitamin K or C ,decreased absorption or increased clearance of the drug ,dietary or drug interactions or hereditary by genetic factors that result either in faster metabolism of the drug (a form of pharmacokinetic resistance) or in lower activity of the drug (pharmacodynamic resistance).

Official Title
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Prevalence of Sub Optimal Anti Coagulation in Patients With Prosthetic Cardiac Valves

Conditions
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Poor Drug Response

Intervention / Treatment
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* Diagnostic Test: Liver and kidney function tests for patients with chronic liver or kidney diseases
* Behavioral: Non compliance of the patient
* Drug: Drug or food interactions


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: All patients of prosthetic cardiac valves undergo warfarin therapy with sub optimal anti coagulation Exclusion Criteria: Refusal of the patients Patients with target INR (2.5-3.5) Patients with hypoalbumenimia and chronic liver diseases
Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Patients with chronic liver or kidney diseases<br>Patients with chronic liver diseases may affect warfarin therapeutic outcome as liver is the site of metabolism of the drug by cytochrome p 450 enzymes so it decrease warfarin absorption Kidney diseases also affect the clearance of the drug these patients will undergo liver function tests and kidney function tests | Diagnostic Test: Liver and kidney function tests for patients with chronic liver or kidney diseases<br>* Tests will be done to patients with history suggestive of chronic liver or renal diseases or for patients clinically suspected<br>* Other names: creatinine - urea;|
| Non compliance of the patient<br>Missed dose of the warfarin or intermittent drug intake may affect drug therapeutic outcome as well as changing time of drug administration during the day | Behavioral: Non compliance of the patient<br>* I will order all my patients to take the drug at 10 am and assure the daily in taking of the dose and they will be followed up<br>* Other names: Asking patient about daily intake of the drug in certain time;|
| Drugs or food interactions<br>Administration of other drugs beside warfarin may affect its therapeutic outcome either by inhibition or synergism certain food may also interfere with warfarin especially vitamin k and c rich food so patients will be followed up for drug or food interactions | Drug: Drug or food interactions<br>* The patient will be in contact with the researcher for any drug added with warfarin in case of other co morbidity conditions and follow up his/her CBC and INR for measuring its effect on warfarin finding out the effect of food on warfarin therapeutic outcome<br>* Other names: Checking other drugs may be added with warfarin and dietary habits;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Measurement of the prevalence of sub optimal anti coagulation in patients with prosthetic cardiac valves | Warfarin therapy is needed in patients with prosthetic cardiac valves to obtain the target INR from 2.5-3.5 . If some patients with prosthetic cardiac valves have sub optimal anti coagulation with INR less than 2.5 with maximal doses of warfarin the research will measure their prevalence in all patients with prosthetic cardiac valves on warfarin therapy and their will be questionnaire for some causes of sub optimal anti coagulation in those patients. The research will fulfill the following questionnaire : Does the patient compliance play a role in warfarin therapeutic outcome? Does changing the time of warfarin administration during the day affect its therapeutic outcome? Does administration of other medication with warfarin including contraception affect its therapeutic outcome? Does dietary habits of certain foods during warfarin administration affect its therapeutic outcome? | 1 year |