Pulmonary Embolism and Pulmonary Hypertension

Question 1

describe thromboembolic disease

Answer 1

deep venous thrombosis

pulmonary embolism

Question 2

describe pulmonary embolism

Answer 2

blockage of pulmonary artery by blood clot, fat, tumour or air (iatrogenic)
usually preceded by DVT, the DVT may silent

Question 3

describe pulmonary infarction

Answer 3

if blood flow and oxygen to lung tissue is compromised the lung tissue may die

Question 4

describe DVT

Answer 4

proximal (ileo-femoral veins);
most likely to embolise and lead to chronic venous insufficiency and venous leg ulcers
distal (polpiteal);
least likely to embolise

Question 5

describe clinical presentation of DVT

Answer 5

can be whole leg or calf involved depending on the site
swollen
hot
red
tender

Question 6

describe differential diagnosis for DVT

Answer 6

popliteal synovial rupture (Baker’s cyst)
superficial thrombophlebitis
calf cellulitis

Question 7

describe investigations of DVT

Answer 7

1st line;
ultrasound doppler leg scan - non-invasive, exlcudes popliteal cyst and pelvic mass

CT scan - ileo-femoral veins, IVC and pelvis
D-dimer test may be elevated

Question 8

describe clinical presentation of pulmonary embolism

Answer 8

dependant on size;
large - cardiovascular shock, low BP, central cyanosis, sudden death, hypoxic

medium - pleuritic pain, haemoptysis, breathless

small, recurrent - progressive dyspnoea, pulmonary hypertension, right heart failure, progressive breathlessness

Question 9

describe risk factors associated with DVT and pulmonary embolism

Answer 9

thrombophilia;
family history, frequency, site, age

contraceptive age;
increased if smoker
HRT

pregnancy (blood thickens)

pelvic obstruction (compressing into venous system);
uterus, ovary, lymph nodes

trauma;
road traffic accident

surgery;
knee, hip, pelvic

immobility;
bed rest, long haul flights (dehydration)

malignancy

obesity

pulmonary hypertension

vasculitis (rare, inflammatory condition of blood vessels)

Question 10

describe prevention of DVT

Answer 10

early post-op mobilisation
TED compression stockings
calf muscle exercises
subcutaneous low dose mol wt heparin periopeatively
direct oral anticoagulant (DOAC) medication;
dabigatran - direct thrombin inhibitor
rivaroxaban/apixaban - direct inhibitor of activated factor Xa

Question 11

describe symptoms of pulmonary embolism

Answer 11

shortness of breath (acute onset)
chest pain (pleuritic)
haemoptysis
leg pain/swelling 
collapse/sudden death

Question 12

describe signs of pulmonary embolism

Answer 12

tachycardia
tachypnoea
cyanosis 
fever (not major)
low BP
crackles
rub
pleural effusion 
low PaO2, low sats (type 1 respiratory failure due to impaired gas exchange, but not CO2 is being retained)

Question 13

describe tests of pulmonary embolism

Answer 13

CXR;
normal before infarction 
basal atelectasis 
consolidation 
pleural effusion 

predicted scores - Well’s criteria, Geneva

pulmonary embolism severity index (PESI) - risk stratification (how likely to die)
ECG - acute right heart strain pattern
d-dimers usually raised (normal = -ve)
troponin +/- BNP/pro-BNP

isotope lung scan - identifies ventilation/perfusion, V/Q = mismatch) . Sensitive for small peripheral emboli and perfusion defect before infarction

CT pulmonary angiogram (CTPA) - images pulmonary artery filling defect to pick up larger clots in proximal vessels. Good for unwell patinets

ultrasound - detects silent DVT

echocardiogram - measure pulmonary artery pressure and right ventricular size (acute dilation of right ventricle in keeping with acute pulmonary embolism)

Question 14

describe underlying causes of pulmonary embolism

Answer 14

obvious - surgery, pregnancy, malignancy, immobility 
autoantibodies (SLE) - antinuclear, anti-cardiolipin abs
thrombophilia screen (rare);
anti-thrombin-III deficiency, protein C or S deficiency, factor V leiden, increased VIII

Question 15

describe treatment of DVT/pulmonary embolism

Answer 15

anticoagulation prevents clot propagation - tips balance to thromobolysis/body dissolves clot
therapeutic dose of S/C low molecular weight heparin - LMWH - dalteparin/fragmin, once daily injection, no monitoring
start warfarin simultaneously (RarE)
rare - IV heparin
antagonises Vit K dependent prothrombin - takes 3 days
after 3-5 days stop heparin when INR>2

alternative treatment;
DOACs (direct oral thrombin inhibitor (dabigatran)) or factor X inhibitor (rivaroxaban/apixaban)

IVC filter to prevent embolisation from large ileofemoral/IVC clot - recurrent PEs (large)
thrombo-embolectomy (RaRE)
intra-catheter directed thrombolysis
EKOS (ultrasound enhanced catheter thrombolysis)

empirical treatment if high clinical suspicion whilst awaiting results
low suspicion await test results before treatment
moderate suspicion, weight out pros and cons

Question 16

describe treatment of pulmonary embolism

Answer 16

thrombolysis - tissue plasminogen activator (tPA) - tenecteplase

life threatening PE (massive);
low BP <90mmHg
severe hypoxaemia, imminent of actual cardiac arrest

Question 17

explain contraindications of pulmonary embolism

Answer 17

relative - pregnancy/post partum, anticoagulants, TIA<6 months, refractory hypertension, advanced liver disease, active peptic ulcer disease, refractory resuscitation
absolute - haemorrhagic stroke/stroke of unknown origin, ischaemic stroke <6 months, cerebral neoplasm or trauma, recent major surgery, trauma, head injury, GI bleeding, known bleeding disorder, aortic dissection, non-compressible puncture

Question 18

describe the duration of treatment for pulmonary embolisms

Answer 18

dependant on balance of risk;
life long - recurrent DVT/PE
6 months - unprovoked 1st PE, high risk proximal DVT
3 months - provoked PE/temporary risk factor, unprovoked low risk distal DVT

IV drug abusers or active cancer
life threatening PE in young men who have high risk of recurrence - life long treatment

DASH score and HERDOO2 for woman

Question 19

describe risk of bleeding/over anti-coagulation

Answer 19

address underlying cause - drug interaction, chronic liver disease, heart failure
if bleeding stop anticoagulant and reverse effect
LMWH and warfarin - long half life
consider prothrombin complex concentrate or fresh frozen plasma
reverse warfarin with vitamin K (liver disease)
reverse heparin with protamine
no reversible agent available for NOACs

Question 20

describe pulmonary hypertension

Answer 20

normal mean pulmonary arterial pressure = 12-120 mmHg
pulmonary hypertension >25mmHg
measured with right heart catheter (secondary invasive)
systolic pulmonary arterial pressure can be estimated with ECHO doppler (possible if >40mmHg but varies with age/weight)

Question 21

describe causes of pulmonary hypertension

Answer 21

pulmonary venous hypertension (left heart disease);
left ventricular systolic dysfunction - ischaemic
mitral regurgitation/stenosis
cardiomyopathy - alcohol, viral

pulmonary arterial hypertension (PAH);
primary pulmonary hypertension
hypoxic - COPD, OSA, pulmonary fibrosis
multiple PE - chronic thromboembolic PH (CTEPH)
vasculitis - SLE, PAN, systemic sclerosis
drugs - appetite suppressants - fenfluramine
HIV
cardiac left to right shunt - ASD, VSD

Question 22

describe cor pulmonale

Answer 22

right heart disease caused by lung disease
fluid retention due to hypoxia +/- heart failure
can complicate COPD, fibrotic lung disease, chronic Pe, chronic ventilatory failure (obesity/kyphoscoliosis)

Question 23

describe clinical signs of pulmonary hypertension and right heart failure

Answer 23

central cyanosis - if hypoxic
dependant oedema
raised JVP with V waves (due to secondary tricuspid regurg)
right ventricular heave at left parasternal edge
murmur of tricuspid regurgitation
load P2
enlarger liver (pulsatile)

Question 24

describe investigations of pulmonary hypertension

Answer 24

ECG - rhythm, axis, p pulmonale, right bundle branch block
CXR - cardiomegaly
sats and arterial blood gases
pulmonary function with DLCO (diffusion capacity)
Echo;
right ventricular systolic pressure
right ventricular dimensions and function
left ventricular dimensions/function
valvular disease

cardiac catheterisation - measures mean pulmonary arterial pressure
d dimer
VQ scan - determines small peripheral perfusion defects
CT pulmonary angiogram - large central clots, mosaic perfusion pattern (small vessel clots)
cardiac MRI
auto-antibodies if vasculitis suspected

Question 25

describe treatment of primary pulmonary arterial hypertension

Answer 25

exclude other secondary causes;
primary disease of the pulmonary arteries/arterioles
progressive exertional breathlessness
worsening PH leads to right heart failure
poor prognosis of 3 years without treamtnet

pharmacologic treatment;
prophylactic anticoagulation (warfarin)
oxygen if hypoxic
pulmonary vasodilators - primary disease only;
calcium channel blocks (oral nifedipine, diltiazem)
Endothelin antagonist (Oral Bosentan, Macitentan)
PDE5-inhibitor (Oral Sildenafil/Tadalafil)
Prostanoids (IV Epoprostenol or Inhaled Iloprost)
Soluble Guanylate Cyclase stimulator (Riociguat)

lung transplant

Question 26

describe chronic thromboembolic pulmonary hypertension (CTEPH)

Answer 26

riociguat - pulmonary arterial vasodilator

pulmonary endarterectomy - curative (2% operative mortality)