Transcript RADICAL PROSTATECTOMY IN A MAN WITH ACUTE DEEP VEIN

THE RATIONAL USE OF
ANTITHROMBOTICS
FOR SURGICAL
PATIENTS
Dr. Hadab A. Mohamed
BACKGROUND
Temporary
interruption
Thrombotic risk
Continuation
Bleeding risk
A great challenge, especially in
the emergency setting
THE CASE…
A 55 years old man was noticed to have a
progressive loss of vision within 2 weeks. His
family took him to the ophthalmology department,
where he was discovered to have a huge suprasellar
mass and was referred to a neurosurgeon.
CASE WORK-UP BY
NEUROSURGEON…
He had an ST elevation MI 2 years ago and a drugeluting stent was placed. No further information is
available.
He also has a history of DVT and PE one month ago
following hemicollectomy and has been maintained
on warfarin.
He is now on aspirin 325 mg, clopidogrel 75 mg,
warfarin 4 mg and atenolol 75 mg by mouth daily.
THE PERIOPERATIVE DILEMMA
The surgeon asked you to assess this man’s
coagulation as the patient is worried about visual
loss and the surgeon wants to do surgery as soon as
possible.
WHAT IS YOUR INITIAL ASSESSMENT
STRATEGY REGARDING THIS MAN’S
COAGULATION?
Initial assessment and risk stratification is based on
Patient
Thrombosis
Interruption
&
Procedure
Bleeding
Continuation
PATIENT RELATED THROMBOTIC RISK?
Indication
dependent
Antithrombotics are indicated for atrial fibrillation, venous
thromboembolism and artificial heart valves.
The thrombotic risk is defined as the risk of
thromboembolism for each condition if not on
anticoagulant therapy
PATIENT DEPENDENT THROMBOTIC RISK
• High risk of recurrent
DVT within the
thromboembolism
preceding month
• 40% per year without
(As in this patient) anticoagulation
Risk in patients
with DVT
During the second • intermediate risk
and third months of • 10% per year without
anticoagulation
treatment
• Low risk
After 3 months of
of recurrence is
oral anticoagulation • Risk
about 1.5% per year
PATIENT DEPENDENT THROMBOTIC RISK
Risk in patients having atrial fibrillation
Patients
with lone atrial
fibrillation and no
other risk factors for
thromboembolism
The lowest
risk of stroke
(less than 1
per cent per
year)
Patients with risk factors
for stroke
Assessed by
CHADS-2
score
Assign one point each for:
*Presence of Congestive heart
failure
*Hypertension
*Age 75 years or older
*Diabetes mellitus
*Assign two points for history of
Stroke or transient ischaemic
attack.
The stroke rate per 100
patient/year without
antithrombotic therapy
increases by a factor of
1·5 for each one-point
increase in CHADS-2
score.
PATIENT DEPENDENT THROMBOTIC RISK
Risk in patients having artificial heart valves
Pts. With artificial
heart valves without
anticoagulation
Incidence of major
thromboembolism is
approximately 4 per cent per
year
valve site
Valve design
The thrombotic risk
is related to
history of
thrombosis
• Mitral position produce a greater
risk than the aortic position.. The
thrombotic risk is increased in those
with more than one prosthetic valve
• Caged-ball have a greater risk than bileaflet valves. Single-leaflet tilting-disc
has an intermediate risk.
• Greater risk of
further thrombosis
PROCEDURE RELATED THROMBOTIC RISK?
Major surgery
100-fold increase in the
absence of thrombolytic
therapy
Minor surgery
Smaller, but definite risk
WHAT FACTORS SHOULD BE CONSIDERED WHEN ASSESSING
INTRAOPERATIVE BLEEDING RISK WITH CONTINUATION OF
ANTITHROMBOTIC AGENTS?
Patient related factors
Procedure related factors
 History of congenital or
 Neurosurgery, vascular surgery
and procedures such as renal
biopsy are potentially
haemorrhagic.
 Major surgeries for sure carry
an extra risk of bleeding than
minor.
 Factors such as the location
and the accessibility means of
controlling bleeding by
packing and suturing should
be considered.
acquired bleeding problems
(e.g. liver failure) are
associated with high risk of
bleeding.
 Use of concomitant
antiplatelet and NSAIDs
increases the chance of
perioperative bleeding.
SO, CAN YOU CLASSIFY THIS PATIENT ACCORDING TO THROMBOTIC &
BLEEDING RISKS?
Our patient is considered at high risk of recurrent
thromboembolism with interruption, and at high
bleeding risk with continuation of antithrombotic
agents.
BACK TO OUR CASE…
The patient is now on aspirin 325 mg, clopidogrel 75 mg,
warfarin 4 mg and atenolol 75 mg by mouth daily.
BASED ON THE THROMBOTIC AND BLEEDING
RISKS, WHAT IS YOUR ADVICE REGARDING
WARFARIN?
The risk of thrombosis and bleeding
should be discussed among the
haematologist, surgeon and
anaesthetist
The risks and benefits of stopping or
continuing anticoagulation should be
discussed with the patient, and an
informed consent should be obtained.
Low bleeding risk
Intermediate bleeding risk
(e.g. dental extractions)
may continue warfarin,
especially if the INR is
within the therapeutic
range.
(e.g. abdominal surgery)
*Further characterization needed, based
on their thrombotic risk.
*Low thrombotic risk: discontinue
warfarin before the procedure.
*Intermediate& high thrombotic risk:
stop warfarin and substituted with
LMWH (Prophylactic dose for the
intermediate thrombotic risk group and
therapeutic dose for the high-risk
group).
If the INR is higher, it
should be allowed to
return to within range
before the procedure.
High risk bleeding
(e.g. neurosurgery) as in
this case):
*Withdraw warfarin and
replace with intravenous unfractionated heparin instead
of LMWH
* Inferior vena cava filter if
there is an additional high
thrombotic risk.
THEN, WHEN IS IT APPROPRIATE TO WITHDRAW WARFARIN BEFORE SURGERY?
Most surgical procedures can be performed safely
(Insignificant bleeding) when the INR is less than 1.5.
For operations with a high bleeding risk (e.g.
neurosurgery), the INR should preferably be less than 1.2.
If the INR is between 2·0 and 3·0, four scheduled doses of
warfarin could be withheld to allow it to fall spontaneously
to 1·5 or less before surgery. Extend this period if the initial
INR is higher.
WITHDRAWAL OF WARFARIN BEFORE SURGERY…
So the INR should be checked the day before
surgery.
If it remains over 2.0, the administration of a low
dose of oral vitamin K (1–2 mg) 24 hours before the
operation should be considered .
THE PRICE TO PAY FOR WARFARIN WITHDRAWAL IS A
POTENTIAL RISK OF POSTOPERATIVE THROMBOSIS.
HOW DO YOU GUARD AGAINST THAT?
A “bridging Therapy” should be instituted, using
heparin, following warfarin withdrawal.
Heparin is started, even preoperatively, once the
INR is less than 2.0 after cessation of warfarin.
SHOULD THE PATIENT BE MAINTAINED ON
HEPARIN THROUGHOUT SURGERY?
The last therapeutic dose of LMWH should be given
no less than 12 hours before operation with a twice
daily regimen, or 24 hours before operation with a
once-daily regimen (Stopping heparin 24 hours
before surgery is always acceptable) .
Intravenous un-fractionated heparin should be
stopped 4–6 hours before surgery.
WHAT ARE YOUR RECOMMENDATIONS REGARDING HEPARIN AND
WARFARIN POSTOPERATIVELY?
A pragmatic approach would be to start LMWH at a
prophylactic dose 12 hours after operation and
increase it over 36 hours, especially in patients with
high thrombotic risk.
If intravenous UFH is chosen, it should be restarted
without a loading dose at a rate of no more than 18
units/kg/h.
POSTOPERATIVE HEPARIN AND WARFARIN...
Warfarin may be restarted (with the same preoperative
maintenance dose) on the evening of surgery or whenever
the patient is able to take oral medications.
Once warfarin therapy is restarted, it can be expected to
take at least 3 days for the INR to reach the usual
therapeutic range of 2.0–3.0.
POSTOPERATIVE HEPARIN AND WARFARIN...
Bridging therapy should be continued until the INR is in the
therapeutic range for 2 consecutive days; in the mean time
bleeding should be monitored once the anticoagulation has
been resumed.
Patients receiving either form of heparin should also have
regular platelet counts to monitor for heparin-induced
thrombocytopenia.
BACK TO OUR CASE…
The patient had an ST elevation MI one year ago and a
drug-eluting stent was placed. He is now on aspirin 325 mg,
clopidogrel 75 mg, warfarin 4 mg and atenolol 75 mg by
mouth daily.
THE PATIENT IS ALSO ON ANTI-PLATELETS, WOULD
YOU LIKE TO DISCONTINUE THEM?
Premature discontinuation of antiplatelet therapy is the
most significant predictor of stent thrombosis , with a
mortality rate of 45%.
This risk is related to the timing
of antiplatelet.
of discontinuation of
WHAT IS THE RISK OF STENT THROMBOSIS WITH ANTI-PLATELETS
WITHDRAWAL?
Discontinuation of clopidogrel during the first month
after coronary stent insertion caries a high risk of stent
thrombosis during the next year.
The same applies to aspirin for a period as long as 15
months after coronary stent insertion
AP WITHDRAWAL……
In addition, the risk of stent thrombosis increases in
patients with renal impairment, diabetes or dehydration.
ACCORDINGLY, WHAT IS THE RISK OF STENT THROMBOSIS
IN THIS PATIENT?
The patient had an ST elevation MI 2 years ago and a drugeluting stent was placed. No further information is available.
He is now on aspirin 325 mg, clopidogrel 75 mg, warfarin 4 mg
and atenolol 75 mg by mouth daily.
Our patient is at low risk of developing stent thrombosis, but
this small risk should be addressed to the patient.
IN SUMMARY…
The patient has an increased risk of thromboembolism
related to both, patient (Recent DVT& PE) and procedure
(craniotomy).
In addition, our patient is at low risk of developing stent
thrombosis.
Having a patient with low risk for stent
thrombosis the surgeon decided to
discontinue AP therapy before surgery
for fear of bleeding. What is your advice
in this respect?
ADVICE….
low-dose aspirin (˂325mg/day) should not be discontinued
before an intended operation or procedure unless there is a
very high bleeding risk as in intracranial surgery and TURP.
However, this might not be reasonable for dual antiplatelet
therapy (aspirin and clopidogrel), as in this case, which is
known to increase the risk of surgical bleeding.
ADVICE….
To identify the proper timing of AP discontinuation
before surgery a risk-based approach may be considered.
 Patients for elective surgery receiving dual antiplatelet therapy
should have surgery postponed until the recommended duration
of clopidogrel therapy is finished.
 If delay is unacceptable , a balance of perioperative risk of stent
thrombosis compared with the possibility of increased surgical
bleeding related to the procedure is acceptable.
ADVICE….
 In situations of high bleeding and low risk of stent
thrombosis, as in this case, the discontinuation of both
clopidogrel and aspirin is logical (at least 7 days before
surgery).
 In scenarios of high thrombotic and low bleeding risk ,
dual antiplatelet drug therapy may be continued until the
day before surgery if at all possible, otherwise,
continuation of at least aspirin should be considered.
WHAT IS YOUR ADVICE TOWARD POSTOPERATIVE RESUMPTION OF AP
THERAPY?
 With high risk of postoperative bleeding, delay restarting
AP until this risk has diminished, and removal of any
indwelling catheters has occurred.
 Careful monitoring for cardiac ischaemia is imperative in
patients who have drugs discontinued because of the high
risk of coronary thrombosis.
 In the emergency situation, platelet transfusion might be
required to correct the thrombopathy induced by AP
therapy.
AN EXTRA MASSAGE FOR THE ANAESTHETIST!!!
Neuraxial block recommendations in patients receiving
anticoagulants& antiplatelets
Prophylactic
LMWH
Therapeutic
LMWH
Delay for at least 24 h before needle insertion
Stop at least 12 h before needle insertion
Removal of
epidural catheter
Subsequent
LMWH dosing
A minimum of 2 h after catheter removal
10–12 h after the last dose of LMWH
AN EXTRA MASSAGE FOR THE ANAESTHETIST!!!
Neuraxial block recommendations in patients receiving
anticoagulants& antiplatelets
IV UFH
Needle placement and catheter removal 4 h after discontinuing heparin
Further
heparin
administration
Delay for 1 h after needle placement
AN EXTRA MASSAGE FOR THE ANAESTHETIST!!!
Neuraxial block recommendations in patients receiving
anticoagulants& antiplatelets
Clopidogrel
Aspirin
Stop 7 days preoperatively
No added risk of spinal haematoma
Emergency surgery
Platelet transfusion should be given before the procedure