Pulmonary Embolism (PE)

Acute Pulmonary Embolism (PE)

PP: blocks center of vascular lumen→vessel distention
or
occludes a vessel→vessel distention

RF: 2nd m/c sudden death
3rd m/c hospitalized pts death
1/1000 people
DVT (60-80%)

E: virchow’s triad
venous stasis→accumulation of platelets+thrombin in veins

endothelial/venous wall injury
-catheter
-PICC lines
-HTN/smoking
-atherosclerosis

hypercoagulability
-factor v leiden mutation
-antithrombin 3 deficiency
-m/c→antiphospholipid sx
-malignancy
-hormone replacement
-OCPs

CM: asx (50+%)
or
abrupt onset
pleuritic chest pain
dyspnea
unexplained breathlessness
tachycardia
tachypnea
hypoxemia
cough
hemoptysis

PE: jugular venous distention (JVD)
deep vein thrombosis (DVT)
hypotension
fever
crackles

rare:
wheezing
s3
s4
cyanosis

DX: clinical+PE findings+vitals
CTA→strong suspicion
SpO2→normal
CBC→leukocytosis
CMP
BMP
PT
PTT
troponin→elevated
BNP→elevated
ABG
d-dimer
EKG
CXR
well’s score
PERC rule
venous doppler
CTA
pulmonary angiography
v/q scan
echo

P: poor cardiac reserve/large vasoconstriction (massive emboli)→pulmonary HTN+RHF
small embolus→dissolved by fibrinolytic system→lung fxn returns to normal

Chronic Pulmonary Embolism (PE)

PP: blocks artery→reduces artery diameter over 50+%→recanalization in thrombus+arterial web

RF: 2nd m/c sudden death
3rd m/c hospitalized pts death
1/1000 change
DVT (60-80%)

E: virchow’s triad
venous stasis→accumulation of platelets+thrombin in veins

endothelial/venous wall injury
-catheter
-PICC lines
-HTN/smoking
-atherosclerosis

hypercoagulability
-factor v leiden mutation
-antithrombin 3 deficiency
-m/c→antiphospholipid sx
-malignancy
-hormone replacement
-OCPs

CM: asx (50+%)
or
abrupt onset
pleuritic chest pain
dyspnea
unexplained breathlessness
tachycardia
tachypnea
hypoxemia
cough
hemoptysis

PE: jugular venous distention (JVD)
deep vein thrombosis (DVT)
hypotension
fever
crackles

rare:
wheezing
s3
s4
cyanosis

DX: clinical+PE findings+vitals
CTA→strong suspicion
SpO2→normal
CBC→leukocytosis
CMP
BMP
PT
PTT
troponin→elevated
BNP→elevated
ABG
d-dimer
EKG
CXR
well’s score
PERC rule
venous doppler
CTA
pulmonary angiography
v/q scan
echo

P: poor cardiac reserve/large vasoconstriction (massive emboli)→pulmonary HTN+RHF
small embolus→dissolved by fibrinolytic system→lung fxn returns to normal

Pulmonary Embolism PP (General)

emboli→obstruction of pulmonary blood flow→increased physiologic dead space→impaired gas exchange→increased pulmonary resistance+loss of alveolar surfactant→atelectasis (collapsed lung)+shrinking of lung tissue+scarring of lung tissue

Embolus Causes

m/c→thrombus

air

• IV infusion

• central venous catheters

• diving

amniotic fluid entering maternal circulation+pulmonary arteries post-delivery

fat moves to BM post-fracture

foreign bodies

parasites

infxn

tumor cells

DVT Embolism

thrombus that forms in femoral vein

below calf/UE→rare

50-60%→develop PE
-50%+embolic events→asx
-50%+DVT→asx

Provoked vs Unprovoked PE

provoked
RF/E that directly caused PE
-virchow’s triad

unprovoked
PE occurred idiopathically (no RF/E)
-need hypercoagulable dx
-ask FHx+ROS/PE→r/o malignancy
-need cancer screening
increased blood clot RF

PE EKG Findings

70% pts→abnormal

m/c dx pattern→S1Q3T3 pattern

other abnormalities:
sinus tachycardia+non-specific ST+T wave changes (40%)
right ventricular hypertrophy (RVH)
right axis deviation
right bundle branch block (RBBB)

PE CXR Findings

m/c→normal

other findings→engorged pulmonary vasculature:

westermark’s sign
blood vessel collapses→hyperlucency

palla’s sign
enlarged right descending pulmonary artery

hampton’s hump
small PE→wedge-shaped opacity
-edge of the lung
-untxd→pleuritic cor pulmonale
E: hemorrhage
pulmonary infarct

Wells Score

estimates probability of PE

guide for further dx screenings

PERC Rule

low probability of PE (wells score u2)

determines if d-dimer is needed→avoids unnecessary testing

all 8 filled→no test
all 8 not filled→d-dimer

D-Dimer

I: low-moderate pretest probability of PE

negative+LOW probability→r/o PE
negative+HIGH probability→no r/o PE

high probability pts→low negative predictive value

high sensitivity+LOW SPECIFICITY (can’t confirm dx)

CT Angiography (CTA)

gold standard+1st line dx→in high-suspicion pts

IV contrast→nephrotoxic

CI: anaphylactic contrast dye allergy
hemodynamic instability
AMI
decompensated CHF
renal impairment

V/Q Scan

CTA not useable/CI to CTA

results equivocal+non-diagnostic

Venous Doppler (Ultrasound)

I: detecting proximal DVT

equivocal for PE V/Q scan→perform

distal/recurrent thrombi+asx pts→less accurate

results:
positive→PE dx
negative→repeat dx x days 1-3+days 7-10→negative→low chance of VTE

Pulmonary Angiography

most accurate
invasive
embolectomy can be done with dx

I: uncertain PE dx
catheter-directed thrombolysis
planned embolectomy

positive→PE dx
negative→r/o PE

Echocardiogram

m/c→normal

I: RV dysfxn
RV strain
pulmonary artery pressure
right chamber emboli

mcconnel’s sign
middle section of RV free wall doesn’t move→right side of heart strain

PE Thrombolytic vs Anticoagulant Mx Tx

thrombolytic
I: hypotension+no high bleeding RF
massive PE+high hypotension RF
high hypotension/hypoxemia death RF

MX: altepase
streptokinase
urokinase

CI: active internal bleeding+stroke x past 2 months
uncontrolled HTN+surgery x past 6 weeks

C: increased major hemorrhagic complications RFs
no difference x 1 week+1 month post-dx compared to heparin/warfarin

P: 24 hrs→resolution of emboli

anticoagulant
I: not tx→secondary prophx

MX:
DOACs
rivaroxaban
apixaban
dabigatran

warfarin “bridge”
heparin→PO warfarin x 6 months
takes ~5-7 days for tx effect

C: doesn’t break down clots→body does that over time
hemorrhage
heparin induced thrombocytopenia (HIT)

PE Duration of Tx

optimal duration→pt specific

considerations

• age

• RFs
  -inherited
  -reversible

• consequences of hemorrhage

• pt functional status

provoked RFs
trauma/surgery→tx x 3-6 months
proximal leg embolism→tx x 6 months

unprovoked PE episode→tx x extended/indefinite

PE NP Tx

embolectomy
I: massive PE
thombolytic CI
unstable post-thrombolytic tx
bad prognosis

C: high mortality rate→last resort tx

IVC filter
I: anticoagulation CI
recurrent VTE despite OAC
massive PE+high recurrent+fatal embolism RF

ROA: reduce short-term PE incidence

C: 2x increase recurrent DVT RF x first 2 years of insertions

P: clinically safe→add OAC
once stable→remove

PE Prognosis

untxd→30% mortality rate
RV dysfxn→10% mortality rate
recurrent VTE→3% mortality rate (rare)

mortality m/c→progressive RHF

1%→chronic thromboembolic pulmonary HTN develops

dx+tx→favorable
perfusion defects→resolve in most