For surgical residents presentation

1. Deep venous thrombosis &
pulmonary embolism
By
Dr Olofin

2. Outline
• Introduction
• History
• Epidemiology
• Relevant anatomy
• Pathogenesis
• Risk factors
• Clinical features
• Investigations
• Management
• DVT prophylaxis in specific situations
• Conclusion

3. Introduction
• Definition- Thrombosis refers to the
formation of solid or semisolid mass in the
circulation from the constituents of the
flowing blood.
• Hence DVT---
• PE- embolisation of part of the thrombus to
the lung.
• DVT-PE occur together; nearly all pat wt
DVT have PE
• Great “masqueraders” of med practice

4. Historical Perspective
• Rudolf Virchow 1856 : Triad & described the emboli concept of PE.
• Lannec: Described PE as a “Pulmonary apoplexy”
• Trendelenburg 1908: Ist Pulmonary embolectomy
• Kirschner 1924: Ist successful Pulmonary embolectomy.
• Sharp 1962: Ist Pulm embolectomy with CPB
• McLean 1916: Discovered heparin as a Medical Student.
• Murray et al 1937: confirmed heparin

5. Epidemiology
• True prevalenc is underreported; most calf DVT’s
are silent . >80% of PE also occur without signs
• Annual incidence - 0.1% in white populations,
• 2.5 million cases of DVT in the US each yr.
• Abt 600,000 affected by PE, abt 150000 die & it
contribute to the death of another 150000
• Ilio-femoral vein most commonly involved. Lt >>
Rt
• Uncommon in the UL
• 90% of PE arise from the deep veins of the leg
• 50% of leg thrombi embolise

6. Epidemiology contd
• Routine autopsy finds PE to be
responsible/contrib to 10-25 % of hospital deaths
• Wtout prophylaxis, fPE occurs in 4-7% hip surg
pats & in 0.1-0.8% gen surg pats

7. Epidemiology contd-
PE Epid/natural history in the US

8. Relevant
anatomy
Superficial venous sys
Deep venous sys
Perforating veins
Calf muscle pump
Upper limb

9. Relevant anatomy contd- Venous
return

10. Relevant anatomy contd-

11. Pathogenesis-VIRCHOW’S TRIAD
• Millions of vascular wall injuries occur daily…
 Vascular wall injury
Injury, inflammation, Previous DVT
 stasis/Flow dynamics alterations
During and after operation, debilitating conditions, eg CVA, Ml,
immobilization.
 Hypercoagulability/viscosity:
a) increase in procoagulants eg clotting factors,
b) Decrease in anticoagulants eg proteins C & S, Antithrombin III
c) Increased Viscosity : Malignancy, D/M, pregnancy,
carcinomatosis, PV, lupus anticoagulant
• Disorders of hemostasis, coagulation, anticoagulation, or
fibrinolysis in the face of the triad leads to recurrent thrombosis

12. Propagation of deep thrombus arising
in a valvular pocket

13. Sequelae of DVT
1. Embolization- most feared sequelae
2. Incomplete recanalisation
3. Complete recanalisation/Resolution- best
outcome.
- 80 % of calf dvts lyse spontaneously
4. 20% propagate = venous obstruction.
5. Organisation
6. CVI/postphlebitic syndrome.

14. Major Risk Factors for the Development
of DVT
Venous stasis Hypercoagulability Vessel wall injury
•Heart disease
Congestive heart failure
Myocardial infarct
•Surgery > 30 minutes
•Immobility(bed rest > 48
hours)
•Paralysis or neurologic
disease
•Age > 40 years
•? Obesity
•Trauma or surgery
•Malignancy
•Chemotherapy
•Oral contraceptive or
hormonal therapy
•Pregnancy
• Inherited thrombophilia
Protein C, S deficiency
AT III deficiency
factor V Leiden
AntiPL antibody syndrome
Dysfibrinogeneamia
Dysfibrinolysis
•Systemic infection or
inflammation
•Blood dyscrasias
•DM
•Hyperlipideamia
•? Dehydration
•Trauma
•Infection
•Previous DVT
•Varicose vein (four times
increase in< 45 years)
• Superficial vein thrombosis
•Central venous catheter or
pacemaker

15. Classification of risk of VTE
• High risk- DVT-40-79% : fPE—1-5%
• gen. & urological surgery in pts >40yrs, recent hx of VTE
• Extensive pelvic or abdominal surgery for malignant ds.
• Major orthopaedic surgery of the lower limb
• Major trauma or Burn + HX of VTE
• Moderate risk: DVT-0-40%, fPE- 0.1-0.7%
• Gen surgery in pts >40yr lasting >30mins pts >40 on oral contraceptives.
• Major trauma or burn
• Low risk- DVT<10%, fPE-<0.1%
• Uncomplicated surgery in pts < 40yrs without additional risk factor
• Minor surgery ie <30mins in age > 40 without additional risk factors.

16. Clinical features
Upper limb(axillosubclavian)
• Primary(spontaneous)
–Post exercise in young healthy indiv/
Saturday night palsy
–Swollen painful arm
–Distended upper chest, shoulder, neck, arm
veins
• Secondary
–Usually following central canulation

17. Clinical features contd
• Lower limbs
–Asymptomatic- 60%
–Painful swelling
–Fever
–Warmth,
–Dilated superficial veins
–Homans sign
–Pratts test
–Phlegmasia cerulea dolens-massively
swollen, bluish mottled limb.Due to
Iliofemoral & supf venous occlusion

18. Clinical features contd -PE
• Mild PE
– Transient tarchypnoea(sudden onset) &
tarchyarrhythmia
• Moderate PE
– Moderate hypotension, tarchcardia, tarchypnoea,
cough wt haemoptysis, pleuritic chest pain, hypoxia,
apprehension, diaphoresis, Rt cardiac failure.
– RAD, incomplete RBBB, S1Q3T3 on ECG
• Severe/ Catastrophic PE
– Cardiac arrest, circ collapse/severe hypotension,
bradyarrhythmia, lt cardiac failure

19. Differential diagnoses of dvt
• cellulitis
• muscle rupture
• trauma
• hematoma
• ruptured popliteal cyst
• lymphedema
• myositis

20. Differential diagnoses of PE
• ARDS
• Aspiration
• Atelectasis
• Heart failure
• Pneumonia
• Sepsis

21. Wells clin prediction rule (A Simplified
Clinical Model for Assessment of DVT)
Clinical variable Score(Points)
Active cancer (treatment ongoing or within previous 6 months or palliative) 1
Paralysis, paresis, or recent plaster immobilization of the lower extremities 1
Recently bedridden for 3 days or more, or major surgery within the previous 12
weeks requiring general or regional anaesthesia
1
Localized tenderness along the distribution of the deep venous system 1
Entire leg swelling 1
Calf swelling at least 3 cm larger than that on the asymptomatic leg (measured
10 cm below the tibial tuberosity)
1
Pitting oedema confined to the symptomatic leg 1
Collateral superficial veins (nonvaricose) 1
Previously documented DVT 1
Alternative diagnosis at least as likely as DVT -2
score ≥3 high probability53%; score 1 or 2-moderate prob17%; & score ≤ 0 -low
prob5% Nxt do D-dimer for low & mod prob OPD pat

22. The Wells score:for PE diagnosis
Criteria Score
Clinically suspected DVT - 3.0 points
Alternative diagnosis is less likely than PE 3.0 points
Tachycardia 1.5 points
Immobilization/surgery in previous 4 weeks 1.5 points
History of DVT or PE 1.5 points
Haemoptysis 1.0 points
Malignancy (treatment for within 6 months,
palliative)
1.0 points
Interpretation
Score >6.0 – High probability 59%
Score 2.0 to 6.0 - Moderate probability 29%
Score <2.0 - Low probability 15%
Do D dimer for OPD
patients

23. Pulmonary Embolism Rule-out Criteria
(PERC rule)
• Designed to rule-out risk of PE in patients
stratified into a low-risk category.
• Patients without any of these may undergo
no further diagnostic testing for PE: Hypoxia
- Sa02 <95%, unilateral leg swelling,
hemoptysis, prior DVT or PE, recent surgery
or trauma, age >50, hormone use,
tachycardia.
• Rationale….

24. Investigations
Gen inv-baseline FBC, INR, aPTT, RFT, LFT,
electrolytes
DVT
• Biochemical
– D dimer- an FDP. >500ng/L
• Radiologic
– Duplex doppler USS- non obliterable vein on probe
compression. Repeat in 1wk if
– Venography- filling defects
– MRV
– Impedance plethysmography- req 50% obstruction
– Radioisotope scan. A125 I Fibrinogen scan

25. Investigations contd
PE
• CXR- Westermark sign, Hampton's hump,
atelectasis, a small pleural effusion, and an elevated
diaphragm.
• ECG-acute cor pulmonale in mod PEs -("S1Q3T3").
Sinus tarchycardia, RAD & RBBB are seen
• Nuclear scintigraphic V/Q scan
• Pulm angiography- gold std
• Multidetector Spiral CT chest/ CT angiography-non
invasive
• MRPV- exptal

26. CXR in PE showing Hampton’s hump

27. V/Q scintigraphy scan

28. Pulm angiogram

29. CT pulmonary angiography (CTPA)

30. Management
DVT Prophylaxis/Prevention
• This entails the totality of measures
adopted to ensure that a surgical patient
or persons at risk do not develop morbidity
or fatality due to venous thrombosis or its
embolism.
• It is a very crucial aspect of surgical
prophylaxis.
• Prevention is the mainstay
• Prevention is costeffective

31. Management contd- Prevention
1)General measures
–Optimise pat eg CCF
–Decrease Op time
–Adequate hydration
periop
–Adequate analgesia &
early mobilisation/
physiotherapy
–Regional instead of
GA.
2)Mechanical measures
a)ES/GCS
b)IPC, venous foot
pumps
c)Electrical stimulation
a)Non-pharmacological measures

32. Management contd- Prevention
b)Pharmacological
– LDUH-SC 5000u bid, 1st dose
2hrs b4 surgery
– LMWH-SC 1mg/kg/day bid.
Start 12 hrs post surg in Ortho
– Warfarin-1mg/day. If periop,
start 4 days b4 procedure wt
aPTT kept <3. Prob-bleeding.
• Prophylaxis is continued for about
7 days after surgery, or until
patient becomes mobile
• C)Surgical
– Venacaval filters
– Indications-anticoagulant
therapy is contraindicated
and/or ineffective, in a pat
for surgery
– Decreases PE & not DVT

33. Management contd-
Treatment of DVT- ACCP guidelines
• Anticoagulation
– Initial anticoagulation with heparin, followed by long-
term anticoagulation with warfarin.
Heparin-
– Mechanism of action- potentiates antithrombin
– Dose: IV loading dose 5000u or 80u/kg infusion then
18 U/kg/h adjusted based on 6hrly INR targeting 1.5-
2.5
– High dose heparin- phlegmasia cerulea dolens &
lifethreatening PE. 20000u bolus ffd by 5000u/ hr IV.
Maintain for 24 hr, then reduce by 500-1000u hrly
until conventional levels if improving

34. Anticoagulation contd
–Side effects of Heparin-
• bleeding,
• Heparin- Induced thrombotic
Thrombocytopaenia(HIT),
• osteoporosis,
• retoperitoneal haemorrhage esp in the
elderly on high doses,
• adrenal haemorrhage

35. Anticoagulation contd
LMWH- 1mg/kg bid.
• Drawback- no good monitor. 1st do AT level
Warfarin- vitamin K antagonist
• Dose-
– Initial doses- 5-10mg for 1st 2 days
– Av maintenance dose -5mg dly(1-10mg dly) modified based
on INR.
• Target INR -2-3. Heparin is stopped after 2 consec days
of target INR
• Side effects- bleeding, teratogenic, warfarin induced
skin necrosis, purple toe syndrome

36. Anticoagulant point of action

37. Contraindications to Anticoagulant Therapy
Absolute contraindications
• Active bleeding
• Severe bleeding diathesis or platelet count ≤20,000/mm3
• Neurosurgery, ocular surgery, or intracranial bleeding within
the past 10 days
Relative contraindications
• Mild-to-moderate bleeding diathesis or thrombocytopenia
• Brain metastases
• Recent major trauma
• Major abdominal surgery within the past 2 days
• Gastrointestinal or genitourinary bleeding within the past 14
days
• Endocarditis
• Severe hypertension (i.e., systolic BP>200 mm Hg, diastolic
BP>120 mm Hg, or both) at presentation

38. Management contd-
Treatment of DVT
• Thrombolysis-
–Urokinase, streptokinase, tPA(Altepase)
–Mech- plasminogen>>plasmin>>clot lysis
–Catheter admin directed locally at
thrombus
–Indications-
• Symptomatic obstr of major upper extremity vein,
• to preserve valve fxn in the lower limb

39. Management contd-
Treatment of DVT
Thrombolysis contd
–Contraind- surgery in last 10 days,serious GI
bleeding in previous 3mths, known HTNsive,
previous CVA, active intracranial process &
bleeding disorder
–Adv- restores a widely patent outflow channel,
preserve and restore normal venous valve
structure and function if performed early
enough(within 1wk)
–Side effect- Intracranial bleeds

40. Management contd-
Treatment of DVT
• Surgical-
Thromboembolectomy
• Indications–
• Extensive clots,
• phlegmasia cerulea dolens and impending venous
gangrene
• poor candidates for fibrinolysis (recent surgery or
trauma involving the CNS or other noncompressible
areas.)
• Preop- clot localisation- doppler/venography

41. Management contd-Treatment of DVT
• Intra-op-
Pre heparinised
Traditional venous thrombectomy using a Fogarty catheter
• Esmarch bandaging if catheter fails to pass due to valves
• A proximal balloon or a temporary caval filter may be used
to reduce the likelihood of embolization
Newer percutaneous mechanical techniques for removal of
an acute obstructing thrombus, including angioscopic
thromboembolectomy, mechanical disruption
thrombectomy, and aspiration thromboembolectomy
• Adjunctive fibrinolysis
• Construction of a small AV fistula may assist in maintaining
patency by increasing the flow velocity through a
thrombogenic iliofemoral venous segment.

42. Management contd-Treatment of DVT
• Post op- to prev rethrombosis
– Heparinisation for 6-12 months afterward.
– Leg compression devices are useful to maintain venous
flow
• Complications of thrombectomy
– failure to clear the deep venous system,
– rethrombosis, &
– PE.
• Follow up- If thrombosis is associated with an
underlying anatomic defect, the defect must be
identified and corrected

43. Management contd-Treatment of DVT
Venacaval filters
• Indications-
– anticoagulant therapy is contraindicated and/or
ineffective,
– Pat who requires urgent surgery that precludes
anticoagulation
– Chronic pulmonary embolism ->pulmonary HTN
– Propagating iliofemoral venous thrombus in
anticoagulation
• Prev PE

44. Recommendations for the Duration of
Anticoagulant Therapy for Patients with DVT

45. Management contd-
Treatment of PE
Surportive- O2, adequate circ, cardiotonic
agents
Anticoagulation
– Wt LMWH as for DVT above is started in patients with
a high or intermediate clinical probability score before
imaging. Massive heparin doses in severe PE
– Oral warfarin is started as soon as PE is confirmed.
INR- 2-3
– Treat for 3-6 mths for a first idiopathic PE & Lifelong
for indiv wt persistent risks

46. Management contd-
Treatment of PE
Thrombolysis
BTS Guidelines recommend thrombolysis for:
• Acute massive PE (causing cardiovascular
collapse.). IV alteplase (tPA) 50 mg bolus having
survived acute episode of PE
• Submassive PE, thrombolyse if haemodynamically
stable & assoc with pulm HTN or right ventricular
dysfxn. IV Alteplase 100 mg is given intravenously
over 90 minutes.

47. Management contd-
Treatment of PE
Pulmonary embolectomy
• Rarely indicated today. Mortality rates range
between 20 and 40%
• Indications- failed thrombolysis or
contraindications to thrombolytics in Pat with
preterminal massive PE
• Performed thru posterolateral thoracotomy with
direct visualization of the pulmonary arteries.
 Newer percutaneous mechanical
techniques- as described under DVT above

48. Management contd-
Treatment of PE
Venacaval filters
• Indications
–Contraind to anticoagulation
–To prev recurrence in survivors of
massive acute PE

49. DVT Prophylaxis in specific
situations
• TOTAL HIP REPLACEMENT
• Most common serious complication of THR
• Most common cause of death within 3/12
• Resp for >50% post-op mortality after THR .
• Without prophylaxis incidence:40% to 70%, with fPE
in =4-7%
• Mortality for PE in THR with prophylaxis is
2.5times>abdominal & thoracic surg. Pt.
• Risk factors: GA vs RA, large blood loss etc
• Risk of developing DVT present x3wks post op with
peak incidence about 4th day post op and minimal
after 7th day.
• Incidence of PE from untreated DVT lasts 3-8wks post
op.

50. DVT Prophylaxis in specific
situations contd
• TOTAL KNEE REPLACEMENT
• Risk of DVT with no prophylaxis 40-84%
• Risk of asymptomatic PE 10-20%
• Symptomatic… PE 0.5-3%
• Fatal PE up to 2%
• Should all get prophylaxis

51. DVT Prophylaxis in specific
situations contd
• SPINE INJURIES
• Highest risk of DVT/VTE among hospitalised pts
• Risk of DVT is high in acute & rehabilitation phase
• DVT occurs 10 times more in paraetic than non-
paraetic limb
• In the absence of prophylaxis objective evidence of
DVT has been reported to be 67-100%
• Optimal duration of thromboprophylaxis not clearly
defined but incidence of VTE after SCI decreases
significantly after 6/12
• Combination of Mech. & Pharm measures most
effective

52. DVT Prophylaxis in specific
situations contd
• TRAUMA PATIENTS
• 3 components of Virchow’s Triad
• Recent trauma 13 fold rise in risk of DVT
• Major trauma plus immobilization –67% of DVT .
fPE –Rare in Trauma Pts.
• No risk-free preventive measure in trauma
patients.
• BURNS: VTE surprisingly rare in extensive burns
• When it occurs anticoagulation is necessary and
requires high dose of heparin

53. DVT Prophylaxis in specific
situations contd
• Tumour Surgery:
• Urologic surgery:
• General surgery
• Vascular surgery
• Transplant surgery
• Travellers dvt.

54. Current recommendations for DVT
prophylaxis
• All hospital inpatients should be assessed for clinical
risk factors and overall risk of thrombo-embolism
• Should receive prophylaxis according to degree of
risk
– Low risk patients should be mobilised early
– Moderate & high risk patients should receive specific
prophylaxis.
• Prophylaxis should continue until discharge
• Surveilance and high index of suspicion needed for
timely diagnosis and 2ndry prevention.

55. •Summary

56. Thank you
For
Listening