MANAGEMENT OF HEMORRHAGE IN PATIENTS WITH MECHANICAL HEART VALVES

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MANAGEMENT OF HEMORRHAGE IN PATIENTS WITH
MECHANICAL HEART VALVES
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Clinical Scenario

• Mr. H.R. is a 62 y.o. white male with PMHx. of
  CAD and Aortic Stenosis. He underwent 3 vessel
  CABG and AVR with St. Jude Valve approximately 4
  years ago. Admitted for elective knee
  arthroscopy and Heparin Window. 48 hours
  post-op developed acute drop in Hgb and left
  flank pain. Abdominal CT revealed large left
  retroperitoneal hematoma.

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CLINICAL QUESTIONS

• What is the risk of temporarily interrupting
  anticoagulation in a patient with a mechanical
  heart valve?
• How long should anticoagulation be held in
  patients with bleeding and mechanical heart
  valves?

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INTRODUCTION

• In March 1960, the first successful replacement
  of an aortic valve was performed by Harkin.
• Approximately 60,000 valve repairs are performed
  annually in the U.S.
• More than 80 models of prosthetic heart valves
  have been developed since the 1950s.

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TYPES OF PROSTHETIC VALVES

• Prosthetic heart valves may be mechanical or
  bioprosthetic.
• Mechanical valves are very durable, most lasting
  at least 20 to 30 years.
• 10 to 20 percent of homograft bioprostheses and
  30 percent of heterograft bioprostheses fail with
  10 to 15 years of implantation.

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TYPES OF PROSTHETIC HEART VALVES

• MECHANICAL
• Caged-ball
  Starr-Edwards
• Single-tilting-disk
  Bjork-Shiley
• 
  Medtronic-Hall
• 
  Omnicarbon
• Bileaflet-tilting-disk St. Jude
  Medical
• 
  Carbomedics
• 
  Edwards-Duromedics
• BIOPROSTHESIS
• Heterograft Hancock
• 
  Carpentier-Edwards
• Homograft

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INCIDENCE RATES OF VALVE THROMBOSIS AND MAJOR
AND TOTAL EMBOLISMS

• Incidence Rates per 100
  Patient-Years
• Anticoagulation Valve Thrombosis Major
  Emb. Total Emb.
• NONE 1.8 (0.9-3.0)
  4.0(2.9-5.2) 8.6 (7-10.4)
• Antiplatelet 1.6 (1-2.5)
  2.2(1.4-3.1) 8.2(6.6-10)
• Coumadin 0.2(0.2-0.2)
  1.0(1.0-1.1) 1.8(1.7-1.9)
• Coumadin AP 0.1(0-0.3)
  1.7(1.1-2.3) 3.2(2.4-4.1)
• Major embolism defined as causing death, residual
  neurologic deficit, or peripheral ischemia
  requiring surgery.

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RISK FACTORS FOR EMBOLIZATION

• Mitral valve prosthesis
• Multiple prosthetic valves
• Caged-ball valves
• Prior CVA
• Atrial Fibrillation
• Age greater than 70
• Depressed left ventricular function

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DAILY RISK OF WITHOLDING ANTICOAGULATION

• Without anticoagulation, the risk of major
  embolism is 4 per 100 patient-years and the risk
  of thrombosis is 1.7 per 100 patient-years.
• The yearly risk of an event would be 5.7.
  However, the risk for 1 day would only be
  (41.7)/365 0.016.

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STUDIES WHICH SUBSTANTIATE A LOW DAILY RISK

• Very limited data available on the risk of
  thromboembolism following discontinuation of
  warfarin because of bleeding.
• Previous studies have focused on the interruption
  of warfarin prior to non-cardiac surgery.
• Available data is limited to case reports and
  small case series

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Intra-cranial Hemorrhage

• Gomez et al., reported a case of hypertensive
  cerebral hemorrhage in a patient on warfarin for
  a Bjork-Shiley aortic valve. Warfarin was
  re-instituted after 10 days without further
  bleeding or thromboembolic phenomenon.
• Babikian et al., reported a series of six
  patients hospitalized with intra-cerebral bleed.
  Five patients survived initial event. Warfarin
  therapy was withheld a mean of 19 days without
  any thromboembolic events during the 6 months of
  follow up.

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Ananthasubramaniam et al How Safely and for How
Long Can Warfarin Therapy Be Withheld in
Prosthetic Heart Valve Patients Hospitilized With
a Major Hemorrhage?

• Design - Retrospective medical record review
• Methods - Retrospective review of 28 patients
  with prosthetic heart valves who were
  hospitalized with a major hemorrhage in the Henry
  Ford Hospital from 1990 to 1997.

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PATIENT POPULATION

• Demographics
• 28 patients included
• Mean age 61 11 years
• 15 men and 13 women
• 35 with atrial fibrillation
• 32 with prior CVA
• 39 with LV dysfunction

• Primary Diagnosis
• 25 patients (89) with GI Hemorrhage
• 2 patients with intra-cerebral hemorrhage
• 1 patient with subdural hematoma

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VALVE POSITION AND TYPE

• TYPE
• 32 valves were present in 28 patients.
• 24 St. Jude valves
• 2 Bjork-Shiley valves
• 2 Starr-Edwards valves
• 4 Carpentier-Edward bioprosthetic valves.

• POSITION
• 12 patients with valves in mitral position.
• 12 patients with valves in the aortic position.
• 4 patients with combined mitral and aortic valves.

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ANTICOAGULATION STATUS AT ADMISSION

• 16 patients (57) with within therapeutic range.
• 7 patients (25) within the sub-therapeutic
  range.
• 5 patients (18) with supratherapeutic
  anticoagulation.

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REVERSAL OF ANTICOAGULATION

• Five of the 28 patients (17) received no
  specific treatment for correction of INR/PT.
• 7 patients (30) received FFP.
• 5 patients (21) received Vitamin K.
• 16 patients (69) received PRBCs.

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SUMMARY OF IN-HOSPITAL COURSE

• Mean duration of warfarin withholding was 15 4
  days. Seven patients (25) had warfarin withheld
  for 1 to 7 days, 13 patients (46) for 7 to 21
  days, and 8 patients (28) for gt 3weeks.
• Four in-hospital deaths felt due to complications
  of initial hemorrhage.
• NO THROMBOEMBOLIC EVENTS DURING HOSPITILIZATION.

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DISCHARGE ANTICOAGULATION

• Twenty-two of the 24 patients were restarted on
  warfarin therapy and had reached an INR gt 2.0 at
  the time of discharge.
• Both patients discharged without warfarin therapy
  had a history of recurrent bleeding episodes.
• One patient with a St. Jude Aortic Valve was
  discharged on ASA.
• The other patient with a St. Jude mitral valve
  was discharged without any anticoagulation.

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SIX MONTH FOLLOW UP

• 21 of the 24 patients were available for follow
  up (all three patients had been restarted on
  warfarin prior to discharge).
• In the 19 patients who were discharged on
  warfarin and available for follow up, there were
  no clinically recognized thromboembolic events.
• The patient discharged without anticoagulation
  died suddenly at home 4 months after discharge,
  and no autopsy was performed.
• The patient discharged on ASA had no
  thromboembolic events.
• 10 patients receiving warfarin had recurrent GI
  bleeding but only 2 had to be hospitalized.

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CONCLUSIONS

• At six months, there were no thromboembolic
  events in hospitalized patients with
  anticoagulation withheld for a mean of 15 4
  days.
• This suggests that warfarin may be withheld from
  14 to 21 days with a low risk of thromboembolism.
• Over half of the patients with GI bleeding had a
  recurrence within 6 months.

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LIMITATIONS

• Small study population and three of the patients
  discharged on warfarin were lost to follow up.
• The thromboembolic risk may be underestimated ,
  since the majority of the patients had St. Jude
  valves and single prosthesis.

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CLINICAL APPLICATION

• Daily risk of thromboembolic events in patients
  with prosthetic valves unable to tolerate
  anticoagulation is low (0.016).
• Limited data seems to agree that the risk of
  discontinuation of therapy is low.
• The source of bleeding should be aggressively
  evaluated and treated.
• Above all, physicians must balance the risk of
  bleeding vs. the benefits of anticoagulation.

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H.R.s HOSPITAL COURSE

• Heparin drip was discontinued.
• Patients HGB stabilized with 2 U PRBC.
• Patient scheduled to follow up with PCP at 2
  weeks from stabilization of HGB for CBC and
  evaluation.
• If stable, he will resume prior dose of coumadin
  with goal INR b/t 2.5-3.5.