Prosthetic Cardiac Valve Replacement: Management Problems

Prosthetic Cardiac Valve Replacement: Management Problems
Navneet Sharma, Anil Grover and Bishan Das Radotra
Asian Cardiovasc Thorac Ann 1998;6:179-182
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The Asian Cardiovascular & Thoracic Annals is the official journal of The Asian Society for
Cardiovascular Surgery and affiliated journal of The Association of Thoracic and Cardiovascular
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Sharma
ORIGINAL CONTRIBUTION
PROSTHETIC CARDIAC VALVE REPLACEMENT
PROSTHETIC CARDIAC VALVE REPLACEMENT:
MANAGEMENT PROBLEMS
Navneet Sharma, MD, Anil Grover, DM1,
Bishan Das Radotra, MD2
Department of Internal Medicine
1Department of Cardiology
2Department of Pathology
Postgraduate Institute of Medical Education and Research
Chandigarh, India
ABSTRACT
Altered states of coagulability can be precarious for patients with valvular pros-
theses. Prosthetic valvular thrombosis can produce devastating hemodynamic
changes wherein surgical intervention might be high risk. We describe the cases
of 4 patients with prosthetic cardiac valve replacements to highlight some of the
problems that might be encountered. The first patient suffered prosthetic valve
thrombosis following withdrawal of her anticoagulants during labor. She was
treated with urokinase but failed to survive. The second young female suffered two
episodes of valvular thrombosis and was successfully treated with streptokinase
on the first occasion but succumbed one year later during the second episode. The
third patient was an elderly male who suffered an intracerebral hemorrhage as a
result of an increase in anticoagulant dosage. He was successfully managed with
low molecular weight heparin. In the fourth case, a young female with a prosthetic
mitral valve had a favorable clinical outcome in spite of withdrawal of anticoagu-
lants during labor.
(Asian Cardiovasc Thorac Ann 1998;6:179–182)
INTRODUCTION
CASE 1
A 23-year-old female diagnosed with chronic rheumatic
Replacement of a diseased and deformed cardiac valve
heart disease underwent mitral valve replacement with
with a prosthesis is a common mode of treatment for
a Medtronic valve (Medtronic Inc., Minneapolis, MN,
patients with hemodynamically significant cardiac val-
USA). She was prescribed oral anticoagulation with 2 mg
vular lesions. In spite of improvement in the quality of
acenocoumarol daily. One year later, she conceived. At
life for the patient, valve prostheses carry an inherent
the 8th month of gestation, she was admitted for a change
risk of complications, mainly thromboembolism and infec-
from oral anticoagulant therapy to intravenous heparin
tion. Treatment of the acquired risk of thrombosis with
therapy. The coagulation profile showed that her inter-
the lifelong use of oral anticoagulant drugs has pre-
national normalized ratio (INR) was 2.5. On echocardio-
vented morbidity to an extent. However, the many im-
graphy, a normally functioning prosthetic mitral valve
provements in the design and quality of prosthetic valves
was visualized. Oral acenocoumarol was discontinued
have not overcome the risk of thrombotic complications.
and intravenous heparin was started in adequate doses to
The following cases illustrate the problems faced in 4
maintain the partial kaolin thromboplastin time at 1.5 to
patients.
1.8 times the control value. She went into spontaneous
For reprint information contact:
labor and heparin was withheld in the second stage of
Anil Grover, DM
labor. While in labor, the patient developed breathless-
Department of Cardiology
ness and cyanosis, she was noted to have tachycardia,
Postgraduate Institute of Medical Education and Research
tachypnea, and hypotension. On auscultation, there was
Chandigarh 160012, India
muffling of the prosthetic valvular sounds and basal
Tel:
91 172 54 1032 Ext. 380
crepitations over the lung bases. She was treated for
Fax:
91 172 54 0401
pulmonary edema. After delivery, her symptoms worsened.
Email: medinst@pgi.chd.nic.net.in.
Intravenous heparin was administered and thrombolytic
1998, VOL. 6, NO. 3
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PROSTHETIC CARDIAC VALVE REPLACEMENT
Sharma
therapy with urokinase was started. The patient continued
to deteriorate in spite of maximal doses of inotropic
agents and soon succumbed to her illness. The clinical
diagnosis of prosthetic valve thrombosis was confirmed
at autopsy (Figure 1).
CASE 2
A 16-year-old female underwent mitral valve replacement
with a Sorin valve (Sorin Biomedical Inc., Irvine, CA,
USA) for chronic rheumatic heart disease. She was taking
3 mg acenocoumarol daily and did not report for follow-
up in the outpatient clinic for supervision of her anti-
coagulation. She was admitted twice with prosthetic valve
thrombosis. On the first occasion, she presented with
acute onset breathlessness and diminished acuity of her
Figure 1. Atrial aspect of the thrombosed mitral valve prosthesis from
prosthetic valvular sounds. Fluoroscopy revealed a dimi-
patient no. 1. The open arrow indicates the valve prosthesis while the
nished opening of the tilting-disc valve. Thrombolytic
closed arrow indicates the thrombosis.
therapy with streptokinase was administered with suc-
cessful results. A complete subsidence of her symptoms
previously, was admitted for a change from oral anti-
was noted. One year later, she was hospitalized again
coagulation therapy to heparin therapy in the 7th month
with acute breathlessness. She admitted to having dis-
of pregnancy. She had been treated with oral aceno-
continued acenocoumarol intake. A Doppler evaluation
coumarol 3 mg daily since her valve replacement and her
showed an end-diastolic gradient of 18.5 mm Hg across
INR had been maintained at 2.5. She was taking aceno-
the prosthetic mitral valve and fluoroscopy showed a
coumarol regularly. A successful change to heparin therapy
reduced opening of the tilting disc. Her INR was 1.6.
in sufficient doses to maintain the partial thromboplastin
Thrombolytic therapy with a streptokinase drip was started
time at 1.5 to 1.8 times the control value was accomplished.
but she developed cardiogenic shock and died.
Echocardiography showed trivial mitral regurgitation with
an insignificant end-diastolic gradient across the mitral
CASE 3
prosthesis. She went on to a full-term pregnancy and
A 59-year-old male had undergone mitral and aortic
heparin was withheld during second stage of labor.
valve replacement for chronic rheumatic heart disease
She delivered a live baby and was discharged on the
with a Starr-Edwards prosthesis (Baxter Healthcare,
10th day after delivery with an INR of 3.0 on 3 mg of
Edwards CVS Division, Santa Ana, CA, USA) 5 years
acenocoumarol.
previously. He presented to the emergency services with
headache, vomiting, slurring of speech, and giddiness.
DISCUSSION
He had been admitted earlier to a primary care hospital
Prosthetic valve thrombosis is the occlusion of a valvular
with a diagnosis of thrombotic stroke. A computed tomo-
prosthesis by noninfective thrombotic material and not
graphy scan at this time revealed two hypodense areas in
by pannus, entrapment of the occluder, infective vege-
the left parietal lobe. He was discharged on an increased
tations, or cardiac structures.l Valve thrombosis includes
dose of 6 mg acenocoumarol daily. On referral to our unit
all new permanent or transient events until evidence is
one month later, his INR was 6.2. A computed tomography
obtained to the contrary at surgery or by clinical investi-
scan of the brain revealed cerebellar hemorrhage and
gation.2 Thrombotic occlusion of prosthetic cardiac valves
hypodense areas in the left parietal lobe with no sur-
has been reported to occur in 1% to 13% of cases following
rounding edema. Treatment with mannitol and furosemide
the implantation of most types of valves including tilting-
was started to prevent cerebral edema, vitamin K and
discs, ball-and-cage valves, and also rarely, biopros-
fresh frozen plasma were administered intravenously, and
theses.3,4 In ball-and-cage prosthetic cardiac valves, the
acenocoumarol intake was discontinued. The prothrombin
function is gradually compromised by progressive fibrous
time normalized with these measures and all signs of
in-growth and thrombus formation. Such mechanical
raised intracranial pressure subsided. He was started on
obstruction causes an increased gradient across the
low molecular weight heparin (parnaparin sodium) in a
prosthetic valve and profound alteration of hemodynamic
dose of 3200 units twice daily, 9 days after his admission.
parameters. When thrombotic occlusion occurs on the
He was discharged in a stable condition on 3 mg of
high-precision dynamics of tilting-disc valves, sudden
acenocoumarol.
malfunction and hemodynamic collapse necessitates
prompt diagnosis and emergency management.4 Karp
CASE 4
and colleagues5 used an actuarial method to estimate the
A 28-year-old female who had undergone mitral valve
cumulative risk of thrombotic occlusion after Björk-Shiley
replacement for chronic rheumatic heart disease 2 years
valve replacement and estimated that at 4 years after
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Sharma
PROSTHETIC CARDIAC VALVE REPLACEMENT
surgery the risk of thrombosis for the aortic, mitral, and
and two relatively small analyses of 16 (13 mitral and
combined aortic and mitral valves was 3%, 13%, and
3 aortic prostheses) and 12 patients (2 aortic, 6 mitral,
13% respectively. The risk of thrombosis for prosthesis
and 4 tricuspid prostheses).14,15 These analyses showed
in the mitral position is greater than for prosthesis in the
successful thrombolysis in 100% and 92% of cases res-
aortic position.6 This is due to the low velocity of blood
pectively. In the first study, 2 patients developed minor
flow across the mitral valve, the small mitral annulus,
systemic embolism and another 2 developed rethrombosis
atrial fibrillation, left atrial enlargement, and left atrial
(mitral position) on follow-up, which necessitated surgical
thrombus at the time of surgery.7
intervention. Two of our patients (no. 1 and 2) underwent
thrombolysis with urokinase or streptokinase. While case
The mechanism of intracardiac thrombus formation in
1 had a dismal outcome, thrombolysis with streptokinase
the presence of a valvular prosthesis depends on 4 factors.
in case 2 was successful on the first occasion. The cata-
Firstly, there is the interaction between plasma proteins
strophic outcome during the second admission of patient
such as fibrinogen and the artificial surface of the
no. 2 was related to failure to adhere to oral anticoagulant
valves. The initial deposition of fibrinogen is followed
therapy, previous use of streptokinase, and a late arrival
by adherence of thrombocytes.8,9 Secondly, there is the
at the hospital.
influence of transmitral blood flow. Thirdly, the slight
hemolysis and platelet destruction at areas of turbulence
Pregnancy in patients with valvular prostheses is a
causes a release of adenosine diphosphate, platelet factor
frequently encountered problem. Many of the earlier case
4, and beta-thromboglobulin that further promote the
reports of pregnancies in women with mechanical valves
thrombotic cycle.9 Lastly, a local hypercoagulable state
arose in the United States where over-anticoagulation
occurs in the area of the replaced valve, which promotes
was frequent with the use of thromboplastins of low
local clotting and platelet deposition. Many factors are
responsiveness.l6 With the advent of the internationalized
responsible for the genesis and maintenance of this
normalized ratio, this problem has been circumvented but
hypercoagulable state: inadequate anticoagulation; loss
to date there are only a few studies analysing the outcome
of atrial contraction; drugs such as oral contraceptives
of pregnancies in women on oral anticoagulants with
and estrogens; other systemic diseases; and the presence
mechanical valvular prostheses. One such study by
of nonbacterial thrombotic vegetations.10,11 All 4 of our
Hanania and colleagues17 of 155 pregnancies in 133
patients had a prosthesis in the mitral position and patient
patients (95 with mechanical and 60 with bioprosthetic
no. 3 also had an aortic valve prosthesis. Patients no. 1
valves) found 16 thromboembolic events associated with
and 2 developed prosthetic valve thrombosis whereas
mechanical prosthesis in 108 pregnancies and thrombosis
patients no. 3 and 4 did not suffer any adverse outcome
was 4 times more frequent with the use of oral anti-
even on withdrawal of anticoagulation.
coagulants. Further analysis revealed that the rate of
miscarriages was higher in those on oral anticoagulants.
The recommended treatment for thrombosis of prosthetic
The success rate of pregnancy in patients with a mechanical
cardiac valves is surgical replacement. Reoperation on
prosthesis was 53%.17 Another retrospective study of 204
prosthetic cardiac valves carries a high perioperative
pregnancies in 184 women (151 pregnancies in 133 women
mortality ranging from 8% to 20% for urgent cases and
with mechanical prostheses) found a success rate of 73%
37% to 54% for emergency cases.12 This high perioperative
in women with a mechanical prosthesis; there were 13
mortality is attributed to the poor preoperative condition
valve thrombosis, 8 embolic events, and 7 hemorrhages
of these patients. Significant experience has accumulated
associated with mechanical prostheses. Most of these
on the medical management of these patients with
complications occurred with the use of heparin.18 Neither
thrombolytic therapy. Thrombolytic therapy may become
of these studies found any increase in the incidence of
the primary modality of treatment to restabilize the valvular
embryopathies associated with the use of oral anti-
orifice and also to reduce operative risk if the patient
coagulants. Our two cases of pregnancy (no. l and 4) also
requires surgery. A study by Birdi and colleagues13 of 158
did not show any malformations of the fetus. The dismal
patients with left-sided prosthetic valve thrombosis showed
outcome in the first case draws attention to the immediate
that the success rate of thrombolysis depended on the
postpartum period when these patients are most vulnerable
adequacy of anticoagulation, prosthesis in the aortic
to thrombosis on sudden discontinuation of heparin
position, the New York Heart Association functional class,
therapy. The state of pregnancy causes an increase in the
and the type of mechanical prosthesis (tilting-disc or
blood coagulability by elevating factor II, V, and VII
bileaflet valve). The success rate of thrombolytic therapy
levels.19 This increase in blood coagulability coupled
in this review was calculated as 68% and was better for
with discontinuation of heparin therapy can have catas-
prostheses in the aortic position and the tilting-disc type.
trophic consequences on the prosthetic valve. In contrast,
However, rethrombosis occurred in 17% of patients.
there was an optimal outcome in case 4 suggesting that
factors other that hypercoagulability may be at play.
Experience of thrombolytic therapy with streptokinase
in the Indian subcontinent is restricted to case reports
Optimal antithrombotic therapy in patients with prosthetic
1998, VOL. 6, NO. 3
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Sharma
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Prosthetic Cardiac Valve Replacement: Management Problems
Navneet Sharma, Anil Grover and Bishan Das Radotra
Asian Cardiovasc Thorac Ann 1998;6:179-182
This information is current as of February 20, 2011
Updated Information
including high-resolution figures, can be found at:
& Services
http://asianannals.ctsnetjournals.org/cgi/content/full/6/3/179
References
This article cites 18 articles, 7 of which you can access for free at:
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