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.
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
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.
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.
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.
