23 - Clotting Disorders VTE Flashcards

1
Q

3 Key Mechanisms
that facilitate
HEMOSTASIS

A

Vascular Constriction

Primary Platelet Plug Formation
Primary Hemostasis

Clot PROPAGATION through FIBRIN formation
Secondary Hemostasis

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2
Q

Define:

Designed to stop bleeding at the site of vascular injury through complex interactions between the vascular endothelium, platelets, procoagulant proteins, anticoagulant proteins, and fibrinolytic proteins

A

HEMOSTASIS

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3
Q

3 Pathways of Coagulation Cascade

A

Intrinsic
12 -> 11 > 11a > 9 > 9a > Xa

Common
X -> Xa

EXtrinsic
8a -> Xa

Xa
Prothrombin (2) –> Thrombin (2a)

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4
Q

Inhibitors of Coagulation Cascade

A

ANTI-THROMBIN 3
Inactivates
the serine proteases:
IIa IXa Xa XIa XIIa
2 9 10 11 12

Protein C & Protein S
attenuates coagulation cascade by proteolysis of 2 cofactors:
Va & VIIIa
5 8
Protein C & S = affected by Factor V Leiden
Defects in these –> ↑CLOTTING / ↑THROMBOSIS

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5
Q

Factor V Leiden

A

Mutation in Factor V Leiden
VVV
Most COMMON defect in natural AC system
VVV
Resistance to inactivation by Protein C** & **S

↑CLOTTING / ↑THROMBOSIS

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6
Q

3 Types of Thrombosis

Thrombosis
formation of an innapropriate fibrin-platelet aggregate on:

A

Thrombosis
formation of an innapropriate fibrin-platelet aggregate on:

  • *Mural**
  • *endothelium** of blood or lymphatic vessel

Cardiac
within the heart

  • *Thromboembolus**
  • *free in lumina of blood** or lymphatic vessel
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7
Q

What is this score used for?

CHADS2 –> CHA2DSVASc

A

ISCHEMIC STROKE RISK
AFIB

Helps determine if you should be on an
Anticoagulant or NOT

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8
Q

Risk Factors for VTE:
VIRCHOW’S TRIAD
+

Important ones

A

B H V

Blood Stasis

Hypercoagulable State

Vascular Injury

Age > 40 / CANCER / TOTAL JOINT ARTHROPLASTY

HORMONAL THERAPY / PREGNANCY

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9
Q

Risk Factors for VTE:
Virchow’s Triad

BLOOD STASIS

A

BLOOD STASIS

Heart Disease

BED REST / IMMOBILIZATION / PARALYSIS

Left Ventricular Dysfunction

Venous Obstruction

Valve Damage from Hypoxemia

CVA

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10
Q

Risk Factors for VTE:
Virchow’s Triad

HYPERCOAGULABLE STATE

A

HYPERCOAGULABLE STATE

Activation of clotting Cascade

Clotting Factor Deficiencies

Mutation in Factor V Leiden
resistance to inactivation by protein C or S mechanism

MALIGNANCY

PREGNANCY / HORMONE REPLACEMENT

H/O Blood Clots

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11
Q

Risk Factors for VTE:
Virchow’s Triad

VASCULAR INJURY

A

VASCULAR INJURY

TRAUMA / SURGERY
Total Joint Artheroplasty
= Hip Surgery

Heart Valve Replacement

Atherosclerosis / Atheromatous Plaque

Indwelling Vascular Catheters

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12
Q

VTE & PREGNANCY

HYPERCOAGULABLE STATE
Virchows Triad - VTE Risk Factors

A

Pregnancy –> ↑VTE Risk by 4-5x

more common in 1st half of pregnancy
20x ↑ risk in POST-partum

Reasons:
Hypercoagulability:Factor 6/8 Fibronogen & Von WIllebrand Factor
Hormonal induced
: ↓Venous capacitance& ↓Venous Outflow
Mechanical Obstruction
byuterus

Additional Risk Factors:
Heart Disease / Sickle / Lupus / Obesity
HTN / Smoking / Diabetes / Anemia

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13
Q

VTE & OCPs

HYPERCOAGULABLE STATE
Virchows Triad - VTE Risk Factors

A

Oral Contraception –> 3-6x VTE Risk
highest in 1st 6-12 months

Proposed Mechanisms:
ProthrombinFactor 7/8/10
Fibrinogen&↑Prothrombin Frag 1/2

Resistance to Activated Protein C

Levels of Protein S

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14
Q

Cancer-Associated Thrombosis

HYPERCOAGULABLE STATE
Virchows Triad - VTE Risk Factors

A

VTE is 4-7x higher in Cancer patients

Additional Risk Factors:

Female / Older Age

BLACK / Prothrombotic Mutations

DM / Obesity / Previous VTE

Atherosclerosis / Inflammation

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15
Q

What is this Score used for?

PADUA PREDICTION SCORE

A

Risk factors for:

VTE** in **HOSPITALIZED MEDICAL PATIENTS

4+ = High risk –> thromboProphylaxis

<4 = could consider prophylaxis

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16
Q

S/Sx of DVT

A

farly nonspecific

Swelling / Redness / Tenderness

Edema of Affectd Limb

Post-Thrombotic Syndrome

Palpable Cord = More Specific

+ Homan’s Sign
(pain w/ dorsiflexion)

17
Q

S/Sx of PE

A

Chest Pain
CP - pleurotic or substernal

Dyspnea / Tachycardia / Palpitation

Hemoptysis / Diaphoresis

Neck vein Distention / Fever

Cyanosis Hypoxemis / Gallop rhythem

Hypotension / Syncope / Oliguria

18
Q

Use for:

D-DIMER

A
  • *RULES OUT DIAGNOSIS OF VTE**
  • not conclusive of diagnosis BUT*
  • *(-) D-Dimer = NOT VTE**

D-Dimer = Blood Test
degradation product produced from breakdown of a fibrin blood clot

Other conditions associated with D-Dimer Elevations:
surgery/trauma + ↑Age
Pregnancy / Cancer

19
Q

What is this Score used for?

WELLS PRETEST SCORE

A

Determining if DVT / PE is likely

>4 + PE S/sx = PE Likely

–> Imaging = CTPA or V/Q

  • *>2 + DVT S/Sx = DVT Likely**
  • different chart*
20
Q

What is this Score used for?

WELLS PRETEST SCORE

A

Determining if DVT / PE is likely

>2 + DVT S/Sx = DVT Likely

–> check CUS / Imaging diagnosis

_>4 + PE S/sx_ = PE Likely
different chart

21
Q

DVT Diagnostic Algorithim

A
  • *WELLS SCORE > 2** = Likely DVT
  • -> Proximal CUS Imaging –> D-Dimer
  • *WELLS SCORE < 2** = unlikely DVT
  • *–> D-DIMER**
22
Q

PE Diagnostic Algorithim

A

WELLS SCORE > 4 = Likely PE
–> confirmation imaging = CT PULMONARY ANGIOGRAPHY
or V/Q

  • *WELLS SCORE < 4** = unlikely PE
  • *–> D-DIMER**
23
Q

Diagnosis:
Imaging Studies for PE

A

CTPA = CT Pulmonary Angiography
1st choice, excellent visualization

V/Q SCAN - used before
inconclusive - impaired by COPD/asthma/CHF
used for:
pregnancy / renal insufficiency / allergies to die

  • *TTE = Transthoracic Echocardiography**
  • noninvasive*
24
Q

What is this score used for?

PESI

A

Pulmonary Embolism Severity Index

Determines the:
30 Day Mortality Risk
VVV
Determines Anticoagulation use

25
Q

Treatment of VTE

DESIRED OUTCOME

A

Aimed at
Preventing Thrombus extention & embolization
recurrence Risk
and preventing long term complications such as:
Post-Thrombotic Syndrome
&
CTEPH = Chronic Thromboembolic Pulmonary HTN