Pulmonary Vascular Disease

Question 1

2 pulmonary vascular diseases

Answer 1

1. pulmonary embolism (PE)

2. pulmonary hypertension (PH)

Question 2

define PE and list out 2 types of PE

Answer 2

is thrombus formation in deep veins of the legs that break off and travel up to embolize in pulmonary arteries

1. provoke - underlying condition/risk factor, unlikely to recur once the provoking factor is gone
2. unprovoked - no underlying cause (or underlying cause not found), likely to recur and requires lifelong treatment

Question 3

thrombus vs blood clot

Answer 3

• thrombus forms in moving blood, blood clot forms in stagnant blood
• thrombus made out of RBCs, platelets, and fibrin
• thrombus white/pale in color while blood clot is red/black

Question 4

risk factors of PE

Answer 4

• recent trauma, injury, fracture
• recent surgery (bed bound)
• cancer (increased clotting factors)
• pregnant (increased clotting factors, fetus pressing on veins)
• significant cardiopulmonary disease (heart failure)
• inherited thrombophilia (V leiden gene)

Question 5

symptoms + signs of PE

Answer 5

SYMPTOMS:

• pleuritic chest pain + cough + haemoptysis (when there is small embolus and necrosis)
• isolated acute dyspnoea (when there are multiple small emboli)
• syncope + cardiac arrest (when there is massive embolism in the main pulmonary artery)

SIGNS:

• pyrexia (result of lung infarct)
• pleural rub
• stony/dull percussion
• tachycardia/tachypnoea (important sign)
• hypoxia
• hypotension (from reduced CO)

Question 6

scoring systems used in PE

Answer 6

1. Wells score - based on symptoms and signs, used to determine likeliness of PE BEFORE diagnosis
2. Revised geneva score - based on risk factors, symptoms, and signs (like HR)
3. PESI score - based on age, comorbidity, physiological parameters (like age) - used AFTER PE diagnosis to risk stratify the patient

Question 7

investigations in PE

* = main diagnosing test

Answer 7

• *CT pulmonary angiogram (CTPA) (allows you to see pulmonary vessels)
• V/Q scan (involves inhaling radioactive particles, used in ppl unfit for CTPA)
• • Echocardiogram (uses USS to show heart chambers, CO, detect pericardial effusion)
• CXR
• ECG
• D-dimer (if -, not PE for sure, of +, could be PE or smth else)
• blood test (biochem, full blood count)
• TnI (troponin levels)
• CT abdomen + mammography
• thrombophilia testing

Question 8

treatment for PE

Answer 8

• O2 (only use this if hypoxic)
• low molecular weight heparin (LMWH) - dalteparin (injected, anticoagulant)
• warfarin (oral anticoagulant, works by blocking formation of vit K dependent clotting factors)
• direct oral anticoagulant - rivaroxaban, apixaban (most commonly used)
• thrombolysis - alteplase (injected, used immediately after heart attack to improve survival, a type of tPA tissue plasminogen activator)
• pulmonary embolectomy (only done in combination with anticoagulant therapy)

Question 9

what is the mech of tissue plasminogen activator?

Answer 9

formed a cleaved product called plasmin, which is an enzyme that dissolved plasma proteins including fibrin

Question 10

define pulmonary hypertension and 2 types of PH

Answer 10

• elevated bp in pulmonary arterial tree of > 25 mmHg
  1. primary PH: rare, 1-2/1 million, quickly progresses to death in young ppl
  2. secondary PH: more common, affects old people, slow-progressing and not fatal

Question 11

cause of PH group 1

Answer 11

idiopathic:
- partial hypertension pf portal venous system (causes 1. cirrhosis, 2. embolism of portal vein)
- collagen vascular disease
- congenital heart disease
- HIV infection

Question 12

cause of PH group 2

Answer 12

secondary to left-sided heart disease:

- issue with mitral valve prolapse –> back flow of blood into the LA –> increased pulmonary arterial pressure

Question 13

cause of PH group 3

Answer 13

secondary to COPD

- damaged lung tissue –> hypoxia –> restricted pulmonary arteries –> pressure buildup that transfers to RV

Question 14

cause of PH group 4

Answer 14

chronic thrombo-embolic pulmonary hypertension (CTEPH):

- webbing + scar tissue that narrows the arteries and result in high BP

Question 15

cause of PH group 5

Answer 15

sarcoidosis

- miscellaneous

Question 16

define portal venous system

Answer 16

veins coming from stomach, intestine, spleen, and pancreas and collecting in portal vein of the liver

Question 17

symptoms of PH

Answer 17

(not very specific)

• exertion dyspnoea + syncope/presyncope (normally the heart would try to increase CO, but in PH this puts more pressure onto the already hard-working heart –> black out)
• chest tightness

Question 18

signs of late stage PH

Answer 18

• elevated JVP
• right ventricular heave
• loud S2 (from delayed pulmonary valve closure or early aortic valve closure)
• hepatomegaly
• ankle edema

Question 19

investigations for PH

Answer 19

• CXR
• ECG (not definitive)
• Echo
• V/Q scan
• CTPA
• right heart catheterization (same as Echo, but more direct measure of phulmonary arteries and CO)

Question 20

general treatment of PH

Answer 20

• treat underlying cause in secondary PH
• O2
• anticoagulants
• diuretics (for the excess fluid and edema)

Question 21

special treatment of PH

Answer 21

• Ca channel antagonist (amlodipine) - single 10mg oral dose daily - pulmonary vasodilator for primary PH
• prostacyclin
• endothelin receptor antagonist (ERA) - bosetan, ambrisetan, macitentan - eliminates endothelin, which causes vasoconstriction
• riociguat - oral soluble guanylate stimulator which stimulates the CO-sGC-cAMP pathway that improves lung capacity
• phosphodiesterase inhibitor - sildenafil, tadalafil - prevent the breakdown of cAMP, resulting in decreased platelet activity
• thromboendarterectomy - dissecting away scar tissue in recurrent PH
• lung and heart transplant - worse case scenario

Question 22

what is the most commonly used drug in PH?

Answer 22

sildenafil (phophodiesterase inhibitor)