“Oral Anticoagulation Therapy” for Heart Valve Disease Management.

1. Managing the Heart
Valve
“ Oral Anticoagulation Therapy”
Dr. Atul A. Maslekar (AIIMS) FICS, FIACS
Sr. Consultant – Cardiothoracic Surgeon
Narayana Multispecialty Hospital -
Ahmedabad

2. Anatomy of Heart Valve

3. Classification of Prosthetic Heart Valve
• Mechanical Valves
• Ball & Cage
• Tilting disc
• Bileaflet
• Biological Valve
• Auto grafts
• Homografts
• Xenografts
• Biovine Pericardial

4. Picture of Mechanical Valve
Tilting disc valve Ball and cage valveBileaflet valve

5. Picture of Biological Valve
Porcine (pig)
stentless valve
Porcine (pig)
stented valve
Bovine (cow)
Pericardial stented valve

6. Management of Patients with Prosthetic Heart
valve
Antithrombotic therapy:
• Fewer complications of Valvular Heart Disease can be more
devastating than systemic embolic.
• Patients with mechanical heart valve receive life long, high
intensity oral anticoagulation therapy to prevent thromboembolic
complications.
• Antithrombotic therapy can reduce although not eliminate the
likelihood of the catastrophe.
• Unfortunately, antithrombotic therapy carries a substantial risk of
bleeding depending upon
– Drugs used
– Intensity of anticoagulation
– Individual

7. Risk of Thromboembolism / Bleeding
Sex: Women have a slightly higher risk of both thromboembolism
and bleeding than men.
• Incidence of Thromboembolism
Women: 0.86 per 100 patient year.
Men: 0.6 per 100 patient year.
• Incidence of Bleeding
Women: 3.1 per 100 patient year
Men: 2.4 per 100 patient year
Age: 50 yr≤ Thromboembolic risk of 0.1 per 100
patient year
> 50 yr Thromboembolic risk of 0.8 per 100
patient year
Risk of bleeding did not vary much with age for patients 70 yr,≤
but was
twice for pt > 70 yrs.
Position of valve: Aortic: 0.5 per 100 patient years
Mitral: 0.9 per 100 patient year
Double valve: 1.2 per 100 patient year.

8. All adverse events Incidence rate for Different
age group

9. All Adverse events according to valve position

10. Incidence of all Adverse events according
to valve type

11. Adverse Events
Minor : Reported but not requiring
additional test or
admission.
Major : Requiring treatment. At least
2 units of blood.
Life Threatening : Leading to Cardiac Arrest
Needing Surgical Intervention
Irreversible Sequelae.

12. Risk factors for Adverse events
• Intensity of treatment
• Patient Characteristics
» H/O GI Bleed
» H/O stroke
» Co morbid Conditions
» Age is controversial
• Frequency of Blood testing
» Patient Compliance
» Additions/ Subtraction of Medicines
» Changes in diet

13. Blood Test for Optimal Anticoagulation
• PT: Traditional method of determining efficacy of
anticoagulation
• INR: A mathematical calculation that corrects for the
results attributable to the variable sensitivities of
thromboplastic agents

14. Ranges
• Healthy People : INR 0.9 – 1.0
• PT with AF : INR 2 – 2.5
• PT with Mech. valve
Mitral INR : 3- 3.5
Aorta INR : 2 – 2.5
Double INR : 3.5 – 4.0
• INR < 2 : ↑ Thromboembolism
• INR > 5 : ↑ Bleeding

15. What is an optimal anticoagulation
therapy?
One at which the Incidence of both Thromboembolic
and Bleeding Complications are the least.

16. Factors affects INR
Medicine : Aspirin ↑
Anti Inflammatory ↑
Antibiotics ↑
OCP’s ↑
Food : Spinach ↑
Lettuce ↑
Brocolli ↑
Liver ↑

17. Management of Adverse Events
Bleeding: 2 general principle
1. attempt to Identify
2. Is there a possibility to lower the
anticoagulation
Minor: > Observe & record
> Repeat PT / INR
> Reassurance
Major: > Admission
> Attempts to Identify the source
> Repeat PT/ INR
> FFP / Fresh blood / Vit K
Life Threatening: > Admission (urgent)
> Urgent Blood transfusion(Blood /
FFP)
> Special Investigation
> Surgical (Invasive) Intervention

18. Management of Adverse efforts –
Thrombosis
Prosthetic valve obstruction may be caused by
– Thrombus
– Pannus
– Combination
Knowledge of clinical presentation & special Investigation (TOE) is
essential as treatment varies,
Pannus: Thrombolytic therapy ineffective
valve thrombectory / replacement
Thrombus: Thrombolysis therapy - Streptokinase
- Urolinase
Duration depends upon resolution of Pressure gradient, valve area +
disc movements

19. Aspirin in Combination with
anticoagulants
• Met analysis supports the concept that the rate of
thromboemboli is diminished with aspirin in Combination with
VIT K antagonist.
• Aspirin in Combination with anticoagulants (INR 2.0-3.5) was
associated with bleeding (minor) incidence of 1.1 – 5.1 % per
patient year.
• Indian senario where INR control is poor due to Poor Patient
Compliance, in addition of aspirin in dosage (75mg – 150 mg)
may be beneficial)

20. Thromboleytic Therapy
• Thrombolytic therapy should be stopped at 24 hrs there
is no hemodynamic improvement or after 72 hrs if
recovery is incomplete.
• If successful → IV heparin until OAC achieves INR 3-4

21. Risks of Thrombolytic Therapy
• Ineffective in 16% - 18% of patients
• Acute mortality – 6%
• Thromboembolism – 12%
• Stroke – 3% - 10%
• Major bleeding expiring - 5%
• Recurrent Thrombosis – 1%
Patient's with large clot, with evidence of valve
obstruction & NYHA III/ IV should under go immediate
reoperation.

22. Regime that we follow - OAC
• OAC usually started on Day 1 Post-OP
• Target INR is achieved by 4-5 days Post-OP
• Use of LMWH/ Heparin in addition
• PT / INR monitoring daily for the full 7 days.
• Aspirin started is dose (75mg – 150mg) for Day 1.
Target INR
• Mitral 3.0 – 3.5
• Aorta 2.5 – 3.0
• Doulle 3.5 – 4.0

23. OAC : Post discharge (Ideal)
• PT/ INR, 1 week post discharge
• Every 15 days thereafter for 3 months
• Once a month for 3 months
• Once every 3 months for 6 months
• 6 monthly there after.
• Continue Aspirin for life.

24. Special Situations
• Pregnancy
• Invasive Procedures

25. Special Situation - Pregnancy
• Unfortunately, no definite fixed guidelines
OAC crosses placenta
– Spontaneous Abortion
– Premature birth
– Still birth
– Embryopathy
Highest risk - 6-12 weeks of Gestation

26. Dose related dependency
Vitale et al J. Am col. card 1999
warfarin > 5mg / day – 9% incidence of
embryopathy
< 5 mg /day – low fetal complication
but no embryopathy

27. • Meschengieser et al – Heart 1999
92 pregnancies in 59 women to MHV
31 pregnancies → Subcut → Heparin 1st
trimester
warfarin – 2nd
Trimester onwards
61 pregnancies → OAC continued
• Abortion / fetal loss → similar
• Embolic effect → 4.9% in Heparin gp
0.3% in OAC gp

28. • Chan et al – Arch. Inter. Med 2000
Review of literature
• OAC throughout → 6.4% embryopathy
• Heparin 6 wks - 12 wks → 9.2 % valve thrombosis

29. LMWH
• More promising
– Does not cross placenta
– No need for frequent patient.
– Lower ½ life
– Lower incidence of thrombocytopenia & osteoporosis
No major recorded data.

30. Recommendations

31. Recommendations
Recommendations for Anticoagulation During
Pregnancy in
Patients With Mechanical Prosthetic Valves: After the
36th
Week
Indication Class
1. Warfarin should be stopped no later than week 36 and heparin
substituted in anticipation of labor.
2. If labor begins treatment with warfarin, a caesarian
section should be performed.
3. In the absence of signification bleeding, heparin ca be resumed
4 to 6 hours after delivery and warfarin begun orally
IIa
IIa
IIa

32. Management of OAC during Invasive
Procedure
• Assess the risk of bleeding v/s risk of Thrombosis
• Elective Procedures
Minor :
– Stop OAC for 1-2 days
– Safely done if INR< 2.0
– Restart OAC immediately.
– Dose of Heparin / LMWH
Major:
– Stop OAC 4-5 days prior
– Switch to LMWH / Heparin
– VIT K 24 hrs prior
– Adequate reserve of FFP / Blood
– Restart OAC as soon as possible.