Anticoagulant in surgery - considerations, contraindications

1. Anticoagulant in surgery
Dr Tenzin Yoezer

2. History
 47 year old
 G5P3A1L3 (Abortion at 2 months)
 Admitted at 41 weeks for IOL
 At the booking Wt = 95 kg
BMI = 45.24 Kg/m2
 Not known case of HTN/ DM
 Screening for HTN and DM at booking – Negative
 No fetal anaomalies at regular USG scan

3.  At T3
Mild pedal swelling
constipation
 No SOB
 No calf pain
 No frontal head ache

4.  All previous deliveries were SVD
 No complications
 PSHx – LEEP in 2003
 Social hx- business
first child from second marriage
age of last child – 21years

5. After admission
 CTG – reactive
 Sweeping
 Ordered CBC, Blood grouping and cross-matching, FBS
and PPBS
 Synto 2.5 U started
 Inj LMWH 80 mg SC OD (Mane)-as for prophylaxis DVT

6. During grand ward-round
 Clinically SFH > POG
 Urgent USG
EFW – 4.173 kg +/- 690 g
AFI – 9.4 cm
 Emergency LSCS but she was on LMWH
 Planned for Elective LSCS + TL
 Discontinue LMWH morning dose on the day of
surgery

7. Examination
 Ht- 145 cm
 Wt – 105 kg (IBW = 40 kg)
 BMI – 50 kg/m2
 Comfortable
 Afebrile
 Not pale
 Mild pedal oedema

8.  PR – 80bpm
 BP – 130/80 mmHg
 NO murmur
 RR – 20 bpm, VB, Grade 2 Mallampati
 SFH – 47 cm
 Cephalic presentation

9. Investigation
 WBC – 6.43
 Hb – 15.7 g/dL
 Hct – 42.5%
 PLT – 257
 FBS – 110 mg/dL
 2 hr PP – 109 mg/dL
 PT – 14 sec ( 13.6 – 17.5)
 INR – 0.85

10. Problem list
1. Morbid obesity
2. Elderly mother
3. On LMWH
4. Large baby
5. Grand Multi para
6. 1st child from 2nd husband
WHO CLASSIFICATION OF OBESITY :
Overweight – BMI of ≥25 to 29.9 kg/m2.
Obesity – BMI of ≥30 kg/m2.
Obesity class 1 – BMI of 30 to 34.9 kg/m2.
Obesity class 2 – BMI of 35 to 39.9 kg/m2.
Obesity class 3 – BMI of ≥40 kg/m2. ( severe,
extreme, or morbid obesity).

11. Intraoperative management
 Confirmed the patient
 Connected to 3 lead ECG, pulse oximeter, NIBP
 BP- 120/80 mmHg
 PR – 100 bpm
 Spo2- 97 % RA
 Spinal anesthesia- Sitting/ midline / L4-5
 luckily was able to palpate her spine easily
 22 G quince needle
 injected 2 mL of 0.5% Heavy bupivacaine
 immediately after lA injection- pt lie down (supine)

12. Intra Op
 After 10 minutes
complained of nausea
but no chest discomfort
BP – 89/49 mmHg ( MAP - 53 mmHg)
PR – 80 bpm
Inj Ephedrine 18 mg IV bolus
Inj Odansetron 4 mg IV bolus
Thereafter uneventful surgery

13.  Delivered baby boy
APGAR – 9/10
Birth weight – 4.02 kg
 Blood loss – 1000 mL
 Fluid – 1 L of R/L

14. Post op
 Right after reaching in the ward complained of
head ache
 Subsided with Diclofenac Na 75 mg IM
 Baby Feeding well
 LMWH 60 mg stat in the ward given and advised
to give for 5 days
 However on Post Op Day 2 – stopped
 Discharged on day 3

15. Use of Anticoagulant in Surgery

16. Introduction
 The management of anticoagulation in patients undergoing
surgical procedures is challenging
 Interrupting - transiently increases the risk of thromboembolism.
 Surgery and invasive procedures have associated bleeding risks
 If the patient bleeds from the procedure, their anticoagulant may
need to be discontinued for a longer period, resulting in a longer
period of increased thromboembolic risk.
 A balance between reducing the risk of thromboembolism and
preventing excessive bleeding must be reached for each patient.

17. Other issues
 vitamin K antagonist (eg, warfarin)- takes several days
until the anticoagulant effect is reduced and then
reestablished perioperatively
 The risks and benefits of "bridging" with a shorter acting
agent, such as heparin, during this time are unclear.
 The newer direct oral anticoagulants (eg, direct thrombin
inhibitor dabigatran, factor Xa
inhibitors rivaroxaban, apixaban, edoxaban) have shorter
half-lives, making them easier to discontinue and resume
rapidly
 But the direct factor Xa inhibitors lack an approved drug-
specific antidote,

18.  approach should be based on expert opinion
 thrombotic and bleeding risks may vary depending on
individual circumstances,
 Data from randomized trials or well-designed observational
studies are not available to guide practice in many settings.
 Thus, approach should be used as clinical guidance and should
not substitute for clinician judgment in decisions about
perioperative anticoagulant management for individual
patients.

19. Decision should be on:
 Estimate thromboembolic risk
 Estimate bleeding risk
 Determine the timing of anticoagulant interruption
 Determine whether to use bridging anticoagulation

20. ESTIMATING THROMBOEMBOLIC RISK
 The major factors that increase thromboembolic risk
are
1) Atrial fibrillation
2) Prosthetic heart valves
3) Recent venous or arterial thromboembolism (eg, within
the preceding three months)

21. Atrial fibrillation
 Accounts for the highest percentage of patients for whom perioperative
anticoagulation questions arise.
 Importantly, patients with atrial fibrillation are a heterogeneous group
 Risk can be further classified according to clinical variables such as:
 age
 hypertension
 congestive heart failure
 diabetes
 prior stroke
 and other vascular disease
 The variables are incorporated CHA2DS2-VASc score

22. CHA2DS2-VASc score
CHA2DS2-VASc risk factor Points
Congestive heart failureSigns/symptoms of heart failure or objective evidence of reduced
left-ventricular ejection fraction
+1
Hypertension-Resting blood pressure >140/90 mmHg on at least two occasions or current
antihypertensive treatment
+1
Age 75 years or older +2
Diabetes mellitusFasting glucose >125 mg/dL (7 mmol/L) or treatment with oral
hypoglycaemic agent and/or insulin
+1
Previous stroke, transient ischaemic attack, or thromboembolism +2
Vascular disease-Previous myocardial infarction, peripheral artery disease, or aortic plaque +1
Age 65-74 years +1
Sex category (female) +1
Note: use of risk scores has not been prospectively validated in the perioperative setting

23. Prosthetic heart valve
 Prosthetic valve who is undergoing an invasive procedure
or surgery should take into account
 the type
 location
 number of prosthetic heart valves
 other risk factors for thromboembolism
 the type of procedure
 Since limited evidence is available, the recommendations
presented are based largely on expert opinion

24. Standardized protocol(2012 American College
of Chest Physicians (ACCP) guidelines)
 Advance planning of perioperative anticoagulant management
(including anticoagulant discontinuation and resumption and
bridging therapy, as applicable),
 Providing patients and providers with a calendar outlining the
timing of anticoagulant changes and INR testing
 Providing education on injection technique for any outpatient low
molecular weight heparin (LMWH) therapy
 Assessment of postoperative hemostasis.

25.  The risk of major bleeding with VKA begins to rise steeply when
INR increases ≥5.
 However, in patients with mechanical valves who require
interruption of VKA therapy, high-dose vitamin K should not be
routinely administered before invasive procedures
 Since this will significantly delay the ability to re-anticoagulate
with VKA after the procedure
 leading to subtherapeutic INRs, increases the risk of valve
thrombosis and thromboembolism.

26.  If the INR is ≥6 without bleeding, VKA should be
stopped to permit a gradual reduction in INR
 small doses (1 or 2.5 mg) of oral vitamin K may be
administered to hasten the fall in INR in patients
with a high risk of bleeding.
 If the INR is >10 without bleeding, VKA should be
discontinued and 1 to 2.5 mg of oral vitamin K should
be administered, with frequent INR monitoring.

27.  Avoid surgery for three months after valve
surgery
The risk of thromboembolism is highest in the first
few months after mechanical or bioprosthetic
mitral replacement or mitral valve repair

28. Recent thromboembolism
 Thromboembolic risk is greater in the immediate period
following a thromboembolic event and declines over time.
 Individuals with a recent thromboembolic event are likely
to benefit from delaying surgery, if possible.
 If emergent surgery is required (eg, acute
cholecystectomy), bridging anticoagulation may be used
to reduce the interval without an anticoagulant.

29. Venous
 The perioperative risk of venous thromboembolism is
 Greatest- in individuals with an event within the prior three months
eg DVT, PE
those with a history of VTE associated with a high-risk inherited
thrombophilia.
 Moderate risk- Individuals with cancer
 low risk - Those with an event more than one year ago have
 Therefore, delaying elective surgery even if the delay is only for a few weeks will be
beneficial.
 This approach is supported by data showing that the recurrence risk for individuals
with a recent VTE is highest within the initial three to four weeks and diminishes over
the following two months
 Without anticoagulation, the early risk of recurrent VTE was approximately 50 percent
 treatment with warfarin for one month reduced this risk to 8 to 10 percent
 after three months of warfarin therapy the risk declined to 4 to 5 percent

30. Arterial
 The risk of recurrent arterial embolism from any cardiac source
is approximately 0.5 percent per day in the first month after an
acute event.
 The vast majority of cases are due to atrial fibrillation
 Other less common cardiac sources include
 paradoxical embolism
 non-bacterial thrombotic endocarditis in a patient with
malignancy
 dilated or poorly contractile left ventricle
 left ventricular aneurysm

31. Risk stratum
Indication for anticoagulant therapy
Mechanical heart valve Atrial fibrillation VTE
Very high thrombotic risk*
Any mitral valve prosthesis
Any caged-ball or tilting disc aortic valve
prosthesis
Recent (within six months) stroke or transient
ischemic attack
CHA2DS2-VASc score of ≥6
(or CHADS2 score of 5-6)
Recent (within three months) stroke or
transient ischemic attack
Rheumatic valvular heart disease
Recent (within three months) VTE
Severe thrombophilia (eg, deficiency of
protein C, protein S, or antithrombin;
antiphospholipid antibodies; multiple
abnormalities)
High thrombotic risk
Bileaflet aortic valve prosthesis and one or
more of the of following risk factors: atrial
fibrillation, prior stroke or transient ischemic
attack, hypertension, diabetes, congestive
heart failure, age >75 years
CHA2DS2-VASc score of 4-5 or CHADS2 score of
3-4
VTE within the past 3 to 12 months
Nonsevere thrombophilia (eg, heterozygous
factor V Leiden or prothrombin gene
mutation)
Recurrent VTE
Active cancer (treated within six months or
palliative)
Moderate thrombotic risk
Bileaflet aortic valve prosthesis without atrial
fibrillation and no other risk factors for stroke
CHA2DS2-VASc score of 2-3 or CHADS2 score of
0-2 (assuming no prior stroke or transient
ischemic attack)
VTE >12 months previous and no other risk
factors

32. ESTIMATING PROCEDURAL BLEEDING RISK
 As a general guideline, procedures are divided into high and low bleeding
risk (2 day risk of major bleeding 2 to 4 percent or 0 to 2 percent,
respectively)
 High bleeding risk procedures include
 coronary artery bypass surgery
 kidney biopsy
 any procedure lasting >45 minutes
 low bleeding risk procedures include
 cholecystectomy,
 carpal tunnel repair
 abdominal hysterectomy
 Dental and cutaneous procedures

33. DECIDING WHETHER TO INTERRUPT
ANTICOAGULATION
 Limited Data
 Decisions that balance thromboembolic and bleeding risks must
be made on a case-by-case basis.
 In general, the anticoagulant must be discontinued if the
surgical bleeding risk is high.
 Those at very high or high thromboembolic risk should limit the
period without anticoagulation to the shortest possible interval
 In contrast, individuals undergoing selected low bleeding risk
surgery often can continue their anticoagulant

34. Settings requiring anticoagulant
interruption
 Individuals with a temporarily very high or high thromboembolic
risk in whom surgery cannot be delayed (eg, potentially curative
cancer surgery in a patient who just had an acute VTE)
 For individuals with a chronically elevated thromboembolic risk
 Individuals with a moderate thromboembolic risk - can interrupt
without bridging
 Temporary interruption of anticoagulation for a minor procedure
such as central venous catheter placement

35. Settings in which continuing the
anticoagulant may be preferable
 Dental procedures – (An exception is multiple tooth
extractions, which we consider high bleeding risk).
 Cutaneous procedures - skin biopsy, tumor excision
 Selected cardiac procedures
 Cardiac implantable devices
 Endovascular procedures and catheter ablation

36. TIMING OF ANTICOAGULANT INTERRUPTION
 Warfarin
 (VKA, PT/INR)
 discontinue warfarin 5 days before elective surgery
(ie,last dose of warfarin is given on day minus 6)
 biological half-life -36 to 42 hours
 check the PT/INR on the day before surgery
 If the INR is >1.5, we administer low dose oral vit K (eg, 1
to 2 mg) and recheck the following day.
 when the INR is ≤1.4 - proceed with surgery

37.  LMWH should be discontinued at least 24 hours
 If a twice-daily LMW heparin regimen - the evening
dose the night before surgery is omitted
 If a once-daily regimen - one-half of the total daily
dose is given on the morning of the day before
surgery.
 Unfractionated heparin –IV infusion until four to five
hours before the procedure
 If S/C, the last dose can be given the evening
before the procedure.

38.  Dabigatran –
 2-3 days with normal or mildly impaired renal function
(ie, creatinine clearance >50 mL/minute),
 2-4 days in those with more severe renal insufficiency (eg,
creatinine clearance between 30 and 50 mL/minute)
 Rivaroxaban - 2-3 days
 Apixaban - 2-3 days
 Edoxaban- 2-3 days
 Clopidogrel 7 days
 Acetylsalicylic acid(Aspirin) – can continue

39. BRIDGING ANTICOAGULATION
 Involves the administration of a short-acting anticoagulant
 LMW heparin or
 Unfractionated heparin
 Aim - to minimize the time the patient is not
anticoagulated, thereby minimizing the risk for
perioperative thromboembolism
 High thromboembolic risk with prolonged interruption of
their anticoagulant [VKA])

40. Need of bridging in individuals taking warfarin for
one of the following conditions:
 Embolic stroke or systemic embolic event within the previous
three months
 Mechanical mitral valve
 Mechanical aortic valve and additional stroke risk factors
 Atrial fibrillation and very high risk of stroke (eg, CHADS2 score
of 5 or 6, stroke or systemic embolism within the previous 12
weeks)
 VTE within the previous three months (preoperative and
postoperative bridging)
 Recent coronary stenting (eg, within the previous 12 weeks)
 Previous thromboembolism during interruption of chronic
anticoagulation

41. Postoperative timing of bridging
 Postoperative resumption of unfractionated heparin and
LMW heparin is similar.
 The resumption of bridging will vary depending on the
surgery type and individual patient considerations
 For those undergoing major surgery or those with a high
bleeding risk procedure - should be delayed for 48 to 72
hours after hemostasis has been secured.
 For most minor procedures associated with a low bleeding
- resume 24 hours after the procedure.

42. URGENT/EMERGENT INVASIVE PROCEDURE
Warfarin
 If semi-urgent (eg, within one to two days),- warfarin should
be withheld and vitamin K administered (eg, 2.5 to 5.0 mg of
oral or intravenous).
 If immediate reversal - prothrombin complex concentrates
(PCCs) or plasma products (eg, Fresh Frozen Plasma [FFP],
 thrombotic risk associated with these products
 used only if there is life-threatening bleeding and
prolongation of the INR by a vitamin K antagonist

43. NEURAXIAL ANESTHESIA
 Should not be used in anticoagulated individuals
 risk of potentially catastrophic bleeding into the epidural space(both
at the time of catheter placement and the time of removal).
 The timing of anticoagulant use in patients receiving neuraxial
anesthesia is illustrated by evidence-based guidelines from the
American Society of Regional Anesthesia (ASRA), which suggest the
following :
 Prophylactic dose LMW heparin (eg, enoxaparin 40 mg once daily):
 Before surgery, wait at least 10 to 12 hours after the last dose of
LMW heparin is administered before a spinal/epidural catheter is
placed.
 After surgery, when there is adequate surgical site hemostasis,
wait at least six to eight hours after catheter removal before
resuming treatment with LMW heparins.

44.  Therapeutic dose LMW heparin (eg, enoxaparin,
1 mg/kg twice daily):
 Before surgery, wait at least 24 hours after the last
dose of LMW heparin is administered before
a spinal/epidural catheter is placed.
 After surgery, when there is adequate surgical site
hemostasis, for twice daily dosing, wait at least 24
hours after catheter removal before resuming
therapeutic-dose LMW heparin.
 For once daily dosing, wait at least six to eight hours
after catheter removal before the first dose;

45. Length of therapy
 The optimal duration of anticoagulation is unknown
 should be individualized on a case-by-case basis.
 However, based upon extrapolated data from the general population as
well as clinical experience, the total duration of anticoagulant therapy
(pregnancy plus the postpartum period) should be at least three to six
months for women whose only risk factors for VTE were transient (eg,
pregnancy, cesarean section)
 Anticoagulant therapy generally continues for at least six weeks
postpartum.
 Patients with persistent risk factors for VTE may require a longer
duration of therapy.

46. American Society of Regional Anesthesia and
Pain Medicine, Number 3, April 2018
 Perioperative Management of Patients on Warfarin:
 Preoperative
 Discontinue warfarin at least 5 days before elective procedure
 Assess INR 1–2 d prior to surgery, if >1.5, consider 1–2 mg oral vitamin
K
 Reversal for urgent surgery/procedure, consider 2.5–5 mg oral or IV
vitamin K; for immediate reversal, consider PCCs, fresh frozen plasma
 Patients at high risk of thromboembolism
○ Bridge with therapeutic SC LMWH (preferred) or IV UFH
○ Last dose of preoperative LMWH administered 24 h before surgery,
administer half of the daily dose
○ Intravenous heparin discontinued 4–6 h before surgery
 No bridging necessary for patients at low risk of thromboembolism

47.  Postoperative
 Patients at low risk of thromboembolism
○ Resume warfarin on POD
 Patients at high risk of thromboembolism (who received
preoperative bridging therapy)
○ Minor surgical procedure—resume therapeutic LMWH
24 h postoperatively
○ Major surgical procedure—resume therapeutic LMWH
48–72 h postoperatively or administer low-dose LMWH
 Assess bleeding risk and adequacy of hemostasis when
considering timing of the resumption of LMWH or UFH
therapy

48. Perioperative Management of Patients on
Antiplatelet Therapy
 Patients with coronary stents
• Elective surgery postponed for the following
durations if aspirin and thienopyridine (eg,
clopidogrel or prasugrel) therapy must be
discontinued
○ Bare metal stents: 6 wk
○ Drug-eluting stents: 6 mo
• If surgery cannot be postponed, continue dual
antiplatelet therapy throughout perioperative
period

49.  Patients at high risk of cardiac events (exclusive
of coronary stents)
• Continue aspirin throughout the perioperative
period
• Discontinue clopidogrel/prasugrel 5 d prior to
surgery
• Resume thienopyridine 24 h postoperatively
patients at low risk of cardiac events
• Discontinue dual antiplatelet therapy 7–10 d prior
to surgery
• Resume antiplatelet therapy 24 h postoperatively

50. Thank You