The Prevalence of Sub Optimal Anti Coagulation

• Conditions: Poor Drug Response
• Interventions: 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

• Registration Number: NCT03485300
• Lead Sponsor: Assiut University

Brief Summary

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

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).

Study Timeline

• Study First Submitted: 2018-03-27
• Study First Submitted QC: 2018-03-27
• Study First Posted: 2018-04-02
• Status Verified: 2018-07
• Last Update Submitted: 2018-07-01
• Last Update Posted: 2018-07-03
• Study Start: 2018-12
• Primary Completion: 2019-05
• Study Completion: 2019-12

Recruitment & Eligibility

• Status: UNKNOWN
• Sex: All
• Target Recruitment: 50

Inclusion Criteria

All patients of prosthetic cardiac valves undergo warfarin therapy with sub optimal anti coagulation

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Exclusion Criteria

• Refusal of the patients
• Patients with target INR (2.5-3.5)
• Patients with hypoalbumenimia and chronic liver diseases

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Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Arm && Interventions

Group	Intervention	Description
Patients with chronic liver or kidney diseases	Liver and kidney function tests for patients with chronic liver or kidney diseases	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
Non compliance of the patient	Non compliance of the patient	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
Drugs or food interactions	Drug or food interactions	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

Primary Outcome Measures

Name	Time	Method
Measurement of the prevalence of sub optimal anti coagulation in patients with prosthetic cardiac valves	1 year	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?