|
| ASPIRIN
THERAPY AND POSTOPERATIVE BLEEDING AFTER CORONARY ARTERY BY
PASS GRAFTING |
| E.
Mujicic, M. Kulic, F.Kucukalic, S.Straus, E. Donlic |
| Cardiac
Surgery Clinic, University of Sarajevo Clinical Center, Bosnia
and Herzegovina |
Introduction
Aspirin, the
salicylic ester of acetic acid, was introduced into medicine in
1899. It is used for its analgesic, antiinflammatory, antipyretic
and antithrombotic effects. More recently, it has been shown that
long-term ( 10 years) regular consumption of Aspirin may lower
the risk of developing colorectal cancer- antiproliferative actions.
Most pharmacology texts state that Aspirin interferes with prostaglandin
synthesis by irreversibly inhibiting cyclooxygenase, one of two
major enzymes that act upon arachidonic acid.
Cyclooxygenase exist in 2 isozymes: Cyclooxygenase -1 or COX-1
and Cyclooxygenase -2 or COX-2. These isozymes are encoded by
different genes, reside in different sites (COX-1 occurs in endoplasmatic
reticulum, COX-2 is found in the nuclear envelope). COX-1 may
be more important for hormonal regulation, hemostasis, and thrombosis,
while COX-2 may be more important in the inflammatory response.
Aspirin acetylates serine in both isozymes. Acetylated COX-1 can
no longer generate prostaglandins. Acetylated COX-2, however,
retains the ability to generate metabolotes of arachidonic acid
that are thought to possess antiproliferative effects.
Antiinflammatory
action of Aspirin is belived to be a result of peripheral inhibition
of prostaglandin synthesis, but Aspirin may also inhibit the action
and synthesis of other mediators of inflammation.
Antipyretic effects of Aspirin are a result of inhibition of prostaglandin
synthesis in the hypothalamus but also be result of Aspirin- induced
peripheral vasodilation and sweating.
The analgesic property of Aspirin is thought to be mainly a result
of periferal actions but direct effects on the CNS are possible.By
inhibiting prostaglandin synthesis, Aspirin decreases the perception
of pain.
Antithrombotic
action
Plateled-derived
COX-1 generates thromboxane A2, potent vasoconstrictor and platelet
agonist. In contrast, entothelial cell COX-1 generates prostacyclin
which possesses vasodilatory and antiplatelet actions. Inhibition
of plateled COX-1 results in decreased platelet aggregation, leading
to a prolonged bleeding time. This is desirable in patients with
coronary artery disease.
Aspirin is recommended for chronic administration in patient with
a known history of coronary artery disease, for myocardial infarcion
prophylaxis, for the treatment of unstable angina, for arterial
throboembolism prophylaxis in combination with warfarin in patients
with prosthetic heart valves....
Platelets are unable to regenerate cyclooxygenase and show impaired
aggregation for approximately seven days. Aspirin should be discontinued
at least 1 week before surgery to minimize postoperative bleeding.
Material
and methods
At Sarajevo
Cardio-surgery Clinic we have observed two groups of patients:
- patients
who stoped taking Aspirin 7 days and more than 7 days before
elective surgery, and
- group
of patients who, due to different reasons, have stoped taking
Aspirin less than 7 days before surgery
Patients are
picked randomly, at the age from 50 to 70 yeras, male, all patients
had coronary artery disease and surgery on the coronary vessels.
Surgery procedure have been the same for all patients ( open heart
surgery with extra corporal circulation). Preoperative findings
on coagulability of blood ( findings include INR, APTT, period
of bleeding and coagulation) have been in normale range. They
have no another disease which can influence on the cagulability
of the blood.
Ahestethic
technique was the same for all patients ( NLA), cardiopulmonalni
by-pass lasted from 1 to 1,5 hours.
12 hours postoperative bleeding ( before starting with Heparine)
was monitored on both groups of patients.
Results
First group
of the patients ( they stoped taking Aspirin more than 7 days
before surgery)
| Patient |
number
of by pass |
Aspirin
stop before surgery |
Bleeding
for 12 postop.hours |
| 64
years |
3 |
9
days |
710ml
|
| 64
years |
3 |
10
days |
720ml |
| 68
years |
3 |
8
days |
670
ml |
| 57
years |
3 |
8
days |
800
ml |
| 65
years |
3 |
15
days |
710ml |
| 65
years |
3 |
15
days |
770
ml |
| 62
years |
4 |
10
days |
590
ml |
| 58
years |
4 |
10
days |
600ml |
| 50
years |
2 |
13
days |
450
ml |
| 58
years |
3 |
1
month |
520
ml |
| 56
years |
2 |
13
days |
440
ml |
| 58
years |
1 |
7
days |
490
ml |
| 61
years |
2 |
1
month |
680
ml |
| 59
years |
3 |
1
month |
740
ml |
| 55
years |
2 |
1
month |
430
ml |
Second groupe
of the patients:
| Patient |
number
of by pass |
Aspirin
stop before surgery |
Bleeding
for 12 postop.hours |
| 70 years |
1 |
1 day |
2200
ml |
| 62 years |
3 |
3 days |
2350
ml |
| 58 years |
1 |
1 day |
1600
ml |
| 57 years |
3 |
3 days |
2150ml |
| 61 years |
3 |
1 day |
1690
ml |
| 58 years |
4 |
4 days |
2730
ml |
| 69 years |
3 |
4 days |
1400
ml |
| 62 years |
3 |
2 days |
2150
ml |
| 62 years |
3 |
3 days |
1400ml |
| 74 years |
2 |
3 days |
1400ml |
| 57
years |
2 |
1
day |
1200ml |
| 59 years |
3 |
2 days |
1300ml
|
| 65 years |
2 |
3 days |
1250
ml |
| 61 years |
3 |
2 days |
1400ml |
| 68 years |
3 |
2 days |
1300ml
|
Conclusion
The postoperative
bleeding (12 hours after the operation) was increased in second
group ( who had stopped taking aspirin less than one week before
the operation). Bleeding was between 1200 ml and 2700 ml in this
group. In the group where aspirin had been stopped more than one
week before the CABG, bleeding was between 400 ml and 800 ml,
in first 12 hours following the operation.
Due to these
reasons, for the second group, we have used more units of blood,
fresch frosen plasma, Trasylol , Minirin and K vitamin. The treatment
of this group was more expensive.
Literature:
- Can pre-operative
antiplatelet treatment increase the need of blood transfusions
during open heart surgery? XXII Congress of the European Society
of Cardiology; August 26-30 2000. Amsterdam
- The effect
of aspirin therapy on thromboelastogram ( TEG) variables patients
exposed to cardio-pulmonary bypass; J K Nanason, N McGill, D
O Shaughnessy, M Herbertson, J Whiteside, R Gill Southampton
General Hospital, Tremona Road, Sothampton, SO16 6YD
- Aspirin,
Telegram 1/ 2001. Abstrakts
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