PE and Pulmonary HTN Flashcards
What is the normal mean pulmonary artery pressure?
15 mmHg (vs systemic artery pressure 100mHg)
What are the causes of pulmonary hypertension?
- Increased LA pressure: mitral stenosis, LVF, diastolic dysfunction
- Increased pulmonary blood flow: left-right shunts, high flow states, excess central volume
- Increased pulmonary vascular resistance:
a. vasoconstriction: low alveolar O2
b. obstruction: embolism, primary pulmonary hypertension
c. obliteration: arteritis, emphysema, pulmonary fibrosis
What is pulmonary hypertension?
Mean PA pressure > 25mmHg
Signs of Pulmonary HTN?
Signs of RHF?
Signs of pulmonary HTN:
- Right ventricular heave
- Loud P2, 4th heart sound
- Prominent v wave in the JVP
Signs of RHF:
- Elevated JVP
- Tricuspid regurgitation
- SOA, ascites, pulsatile liver
Normal pH, PaCO2, PaO2, HCO3 values?
pH: 7.35-7.4
PaCO2: 35-45 mmHg
PaO2: 80-100mmHg
HCO3: 22-26 mmHg
DDx of PE
- Angina, unstable:
- MI: STEMI, NSTEMI
- Pneumonia
- Bronchitis, acute
- COPD acute exacerbation
- Asthma, acute exacerbation
- CHF, acute exacerbation
- Pericarditis
- Cardiac tamponade: muffled heart sounds, pericardial rub, LVF (crackles in chest), pulsus paradoxus ( > 15mmHg drop in BP)
Ix of PE
- CXR
- CT-PA: Dx test of choice; good negative predictive value (low risk of PE if it is negative)
- V/Q scan: combine with clinical probability
- ECG: right axis deviation; sinus tachycardia*; RBBB; right ventricular strain pattern
- D-dimer (fibrin degradation product):
- good tool to rule out PE, and should be ordered in all patients with suspected PE
- Only order if PE is unlikely cause, but want to rule out. High sensitivity, low specificity with low clinical probability for PE - ABG: hypoxia and hypocapnia are suggestive
- Well’s score
- Geneva score
- If pregnant: Doppler US for DVT only
Where do PEs come from?
** Most common: DVT flicking off
Other sources are v. v. rare:
- Fat: post trauma (especially of large long bones)
- Air: post lap surgery
- Amniotic fluid
- In situ thrombosis
What are the two scores that are used to calculate the risk of having a PE?
- Wells Score.
Purpose: Calculates risk of having PE (rules in PE)
- Symptoms of DVT (3 points)
- No alternative diagnosis better explains the illness (3 points)
- Tachycardia with pulse > 100 (1.5 points)
- Immobilization (>= 3 days) or surgery in the previous four weeks (1.5 points)
- Prior history of DVT or pulmonary embolism (1.5 points)
- Presence of hemoptysis (1 point)
- Presence of malignancy (1 point)
If score is
Score > 6: High probability
Score >= 2 and <= 6: Moderate probability
Score < 2: Low Probability
- rGeneva (revised Geneva) Score
- Age 65 years or over 1
- Previous DVT or PE 3
- Surgery or fracture within 1 month 2
- Active malignant condition 2
- Unilateral lower limb pain 3
- Hemoptysis 2
- Heart rate 75 to 94 beats per minute 3
- Heart rate 95 or more beats per minute 5
- Pain on deep palpation of lower limb and unilateral edema 4
The score obtained relates to probability of PE:
0 - 3 points indicates low probability (8%)
4 - 10 points indicates intermediate probability (28%)
11 points or more indicates high probability (74%)
Determines Ix to be obtained: D-dimer, CXR, V/Q, CT-PA
Clinical Features of PE
Need to have a high level of suspicion in certain situations:
- Presence of RF
- Chest pain
- Unexplained breathlessness
- Presyncope or syncope
- Tachypnoea
- Evidence of pulmonary HTN (and no clear cause)
- Hypotension (BP < 90mmHg)
Risk Factors of PE
Strong:
- Increasing age
- Dx of DVT
- Surgery w/in last 2 months
- Bed rest > 5 days
- Previous venous thromboembolic event
- FHx of venous thromboembolism
- Active malignancy
- Recent trauma or fracture
- Pregnancy or postnatal period
- Factor V leiden mutation
- Anti thrombin III deficiency, Protein C def, Protein S def
- Antiphospolipid antibody syndrome
Prevention of PE - explain primary and secondary measures
Primary prevention of PE is mainly targeted at DVT prophylaxis:
- Perioperative LMWH e.g. clexane
- NOACs: apixaban, edoxaban, rivaroxabn, dabigatran
- Early mobilisation reduces risk
- Elastic stockings
Secondary prevention of PE is with oral anti-coagulants:
- Warfarin is usually the choice of drug in most situations e.g. PE secondary to provoked, unprovoked PE, intial PE w/ malignancy, etc
- Maintain INR 2-3
What does this show?
Bilateral PE
Rx of high suspicion of PE
1st: Oxygen +/- mechanical ventilation, plus:
-
Anti-coagulation: adminster immediately in all patients who present with suspected PE unless C/I
- IV Unfractionated Heparin or LMWH
- LMWH (clexane) preferred as it acheives therapeutic levels immediately, lower major bleeding incidence, lower risk of heparin induced thrombocytopaenia
- Warfarin is started at ths same time as one of the above, and is continued until INR is 2-3 for 2 consecutive days, at which point UFH or LMWH can be discontinued
If BP less than 90mmHG:
- IV resuscitation
- Vasopressor therapy (anti-hypertensive and inotrope): noradrenaline or dobutamine
Rx of confirmed PE
1st line: Oxygen +/- mechanical ventilation, plus:
-
Anticoagulation: mainstay treatment
- LMWH and warfarin for goal INR 2-3
- Reduces mortality significantly (30% drops to 2-8% mortality)
- Continue for app 6 months for warfarin when INR established
- Order:
- i. heparin (first to bridge): usually LMWH; AFx: risk of bleeding; renal impairment
ii. warfarin (second, as steady state takes few days): INR 2-3 monitoring
iii. NOACs: rivaroxaban, dabigatran
- i. heparin (first to bridge): usually LMWH; AFx: risk of bleeding; renal impairment
- Thrombolysis * reserved for most severe cases
- C/I haemorrhagic stroke, ischaemic stroke 6 mths before, recent surgery or head injury, GIT bleeding
- Alteplase, reteplase
If BP < 90 mmHG, add:
- IV resuscitation
- Vasopressor
If excessive risk of bleeding or failed thrombolysis, add:
- IVC filter placement (prevention rather than Rx, removalafter 30 days if indicated)
- C/I to anticoagulation (e.g. gliobastoma),
- Failure of anticoagulation or
- If further PE may be lethal
What does this picture show?
Prominent hilar regions due to enlarged pulmonary arteries & RV grossly enlarged
consistent with pulmonary hypertension
What does this show?
CT – grossly dilated central pulmonary arteries, normal lung parenchyma, no acute PE
Pregnancy - increases pulmonary HTN (primary HTN)
Diagnostic classification of pulmonary arterial HTN
