Pulmonary Hypertension Flashcards
What is pulmonary HTN?
A syndrome with marked remodelling of pulmonary vasculature and rise in pulmonary vascular load → remodelled and hypertrophied RV
Divided into 3 haemodynamic categories and 5 clinical categories
Haemodynamic categories:
Precapillary
Postcapillary
Combined pre and postcapillary
Clinical categories:
1) PAH
2) L heart disease
3) Lung disease/ hypoxia
4) Pulm art obstruction
5) Miscellaneous
Haemodynamic categories in Pulm HTN
Haemodynamic categories:
Precapillary
- mPAP >20mmHg
- PAWP ≤15mmHg
- PVR >2WU
Isolated Postcapillary
- mPAP >20
- PAWP >15
- PVR ≤2WU
Combined pre and postcapillary
- mPAP >20
- PAWP >15
- PVR >2WU
Exercise PH
mPAP/CO slope between rest and exercise >3mmHg/L/min
________
Unclassified PH
- mPAP >20
- PAWP ≤15
- PVR ≤2
This group may have CHD, liver disease, airway disease, lung disease or hyperthyroidism –> needs Ix and follow-up
Clinical classifications of pulmonary HTN
Class 1: Pulm Artery HTN (PAH)
subcategories:
Idiopathic
Heritable
Drug/ toxin induced
PAH assoc with
CTD/
HIV/
Portal HTN/
Schistosomiasis
Class 2: PH due to L-sided heart disease
Class 3: PH due to lung disease, hypoxia or both
subcategories:
Obstructive lung disease
Restrictive lung disease
Mixed restrictive-obstructive pattern
Hypoxia w/out lung disease
Developmental lung disorder
LAM
Class 4: PH due to pulmonary art obstruction
Class 5: Miscellaneous
Subcategories:
Haematological
Systemic/ metabolic disorders (e.g. PLCH, neurofibromatosis, sarcoidosis)
Functional Classification in Pulm HTN
Investigation for pulm HTN workup
- Cardiac tests: Echocardiogram, ECG, R heart catheter
- Bloods:
FBC, RP, LFT, TFT
Uric acid, iron studies, BNP, viral screen,
CTD screening (ANA, anti-centromere, dsDNA, anti-Ro, U3-RNP, U1-RNP)
Thrombophilia screen in CTEPH: Antiphospholipid, Anticardiolipin, lupus anticoagulant - Imaging: CXR, HRCT, CTPA/ VQ scan/ Dual-energy CT (DECT), cardiac MRI, Abdo USS (TRO portal HTN)
- Respi tests:
a) Lung function test - FVC%/DLCO% ≥1.39, or
- reduced DLCO when others are normal
b) 6MWT,
c) CPET - used in intermediate probability of Pulm HTN from echo.
- CPET features:
low end-tidal partial pressure of carbon dioxide (PETCO2),
high ventilatory equivalent for carbon dioxide (VE/VCO2),
low oxygen pulse (VO2/HR), and
low peak oxygen uptake (VO2)),
d) PSG
Diagnostic algorithm for pulm HTN
Echocardiogram features suggestive of pulm HTN
PASP = Right ventricular systolic pressure (RVSP) = >20
- If no pulm valve stenosis or outflow obstruction
RVSP = 4x(TR jet Max Velocity)2 + Right Atrial Pressure (RAP)
TR velocity
>2.8m/s – intermediate risk
>3.4m/s – high risk
Images on ECHO:
Normal: roundish & thick wall LV
PH:
flattening of interventricular septum D-shaped LV
LV being pushed to the side
No LA being pushed and cant been seen
Right Heart Catheterisation
Mx of PAH
positive vasodilator response = drop in mPAP >10 to value ≤40mmHg
General:
1) Diuretic/ ROF/ low salt diet to achieve euvolemia
2) Supp O2 if needed to achieve PaO2 >60mmHg
3) Diet & exercise.
4) Correction of iron-def even without anaemia
5) Contraception for female childbearing age
- if preg, stop ERA, riociguat & selexipag (teratogenic).
- give counselling if pregnant, consider TOP in high risk
6) Vax: covid vax, fluvax, pneumococcal vax
7) Psychological support/ Genetic counselling if appropriate
8) Any surgical procedure is high risk, thus to decide in MDT
9) Travel - use in-flight O2 if sea level PaO2 <60mmHg or SpO2 <92%
Check for vasodilator response:
a) If yes –> start high dose CCB. Add on PAH Rx if no response or loss of vasodilator response in 1y
b) If no –> Ax risk using REVEAL score (predicts survival at 1y in PAH)
i) in low-intermediate risk: dual-combination therapy (ERA + PDE5i), then f/up in 3-6m –> check:
- echo, BNP, 6MWT/ BORG
#in pt with comorbidities, use single agent first
ii) in high risk: evaluate for lung transplant, and triple- combination therapy (ERA + PDE5i + prostacyclin analogue), then f/up in 3-6m –> check
- echo, BNP, 6MWT/BORG
Drugs and toxins which are assoc with PAH
Sx of Pulmonary HTN
Signs of pulm HTN
ECG abnormalities in pulm HTN
Radiographic features suggestive of Pulm HTN
Characteristics of pts with Pulm HTN based on specific categories
Risk Ax in PAH
Dosing of PAH meds
PAH medication (specific pathway)
3 main pathways:
1) Endothelin pathway (Endothelin Receptor Antagonist, ERA)
- Selective ERA: Ambrisentan
- Dual ERA: Bosentan, Macitentan
teratogenic
2) Nitric oxide pathway
- sGC stimulator: Riociguat
- PDE5 inhibitor: Sildenafil, Tadalafil
3) Prostacyclin pathway
- Prostacyclin analogue: Iloprost, epoprostenol, treprostinil
- Prostacyclin receptor agonist: Selexipag
Bosentan reduced Sildenafil & OCP efficacy. Bosentan also interacts with Warfarin
Group 4 PH secondary to CTEPH
Risk factors:
a) permanent intravascular devices (pacemaker, long-term central lines, ventriculoatrial shunts),
b) inflammatory bowel diseases,
c) essential thrombocythaemia,
d) polycythaemia vera,
e) splenectomy,
f) antiphospholipid syndrome,
g) high-dose thyroid hormone replacement,
h) malignancy
In acute PE, consider CTEPH if:
1) if radiological signs suggest CTEPH on the CTPA and/or
2) if estimated sPAP is >60 mmHg on echocardiogram;
3) when dyspnoea or functional limitations persist in the clinical course post-PE
and
4) in asymptomatic patients with risk factors for CTEPH or a high CTEPH prediction score
Ix:
VQ scan most effective
Others like DECT and MRI perfusion - lack validation
CTPA negative does not rule out CTEPD (as distal disease may be missed)
Screening for antiphospholipid syndrome
Rx:
a) Pulmonary endarterectomy (PEA) - surgical candidate & thrombus accessible
b) Balloon Pulm Angioplasty (BPA) - not surgical candidate can still be considered
c) Lifelong therapeutic anticoagulation
- Warfarin for antiphospholipid syndrome.
- Retrospective case series from the UK and a multicentre prospective registry (EXPERT) showed comparable bleeding rates for VKAs and NOACs but recurrent rates higher in NOACs
- Riociguat
- Treprostinil subcut
Group 5 PH
