26 Pulmonary Hypertension and functional assessment of right ventricle Flashcards
What are the definitions of pulmonary hypertension, pre-capillary hypertension and post-capillary hypertension?
Pulmonary hypertension is MPAP ≥25mmHg
Pre-capillary pulmonary hypertension is PCWP ≤15 mmHg.
Post-capillary pulmonary (left heart disease) hypertension is PCWP >15 mmHg.
What are the 5 WHO classes of pulmonary hypertension?
- Pulmonary arterial hypertension (primary)
- Pulmonary hypertension due to left heart disease
- Pulmonary hypertension due to lung disease
- Pulmonary hypertension due to chronic thromboembolic disease
- Pulmonary hypertension due to an unknown cause (idiopathic)
What is the pathophysiology of the 5 WHO classes of pulmonary hypertension?
- Pulmonary arterial hypertension (primary) (e.g. idiopathic, inherited, drug/toxin-induced, congenital, connective tissue disease, persistent pulmonary hypertension of the newborn). In group 1 PH, the arteries in the lung become stiff and narrow so the RV works harder to overcome the resistance.
- Pulmonary hypertension due to left heart disease (e.g. VHD, LV systolic/diastolic dysfunction). In group 2 PH, AV/MV disease or LV systolic/diastolic dysfunction decrease the ability of the left heart to act as a reservoir so blood backs up into the pulmonary system.
- Pulmonary hypertension due to lung disease and/or hypoxaemia (e.g. COPD, ILD, OSA). In group 3 PH, the arteries in the lungs constrict, to direct blood to oxygenated areas.
- Pulmonary hypertension due to chronic thromboembolic disease (e.g. PE). In group 4 PH, chronic thrombi in the lungs fibrose and block the arteries in the lungs.
- Pulmonary hypertension due to an unknown cause (secondary) (e.g. sarcoidosis, lymphangiomatosis).
What are the symptoms and signs of pulmonary hypertension?
The symptoms of pulmonary hypertension include dyspnoea, fatigue, cough, dizziness, syncope, peripheral oedema and/or symptoms of the underlying cause.
The signs of pulmonary hypertension include elevated JVP, parasternal heave, loud pulmonary component to second heart sound P2, TR, peripheral oedema and/or ascites.
What are the associated characteristics of pulmonary hypertension?
RV and RA dilatation, RVH, pulmonary artery dilatation and decreased RVOT acceleration time (<105ms).
MV disease, AV disease, left to right shunts, LV dysfunction and PE.
How is RA pressure calculated?
If the IVC is normal in size (<2.1cm) with normal inspiratory collapse (>50%), the RA pressure is 3mmHg.
If the IVC is dilated (>2.1cm) or the IVC shows decreased inspiratory collapse (<50%), the RA pressure is 8mmHg.
If the IVC is dilated (>2.1cm) with decreased inspiratory collapse (<50%), the RA pressure is 15mmHg.
How is PASP calculated and assessed?
PASP is dependent on TR which is dependent on the pressure gradient between the RA and RV.
RVSP – RAP = 4 x (TR Vmax)2
RVSP = 4 x (TR Vmax)2 + RAP
RAP estimate = IVC size and change with inspiration
RVSP = PASP
How is PADP calculated?
PADP is dependent on PR.
PADP – RVDP = 4 x (PR Vmax)2
PADP = 4 x (PR Vmax)2 + RVDP
RVDP = RAP estimate = IVC size and change with inspiration
How is pulmonary hypertension assessed by the BSE?
If the TR velocity is ≤2.8m/s and there are <2 TTE categories, the echo probability of pulmonary hypertension is low.
If the TR velocity is ≤2.8m/s and there are ≥2 TTE categories, the echo probability of pulmonary hypertension is intermediate.
If the TR velocity is 2.8-3.4m/s and there are <2 TTE categories, the echo probability of pulmonary hypertension is intermediate.
If the TR velocity is 2.8-3.4m/s and there are ≥2 TTE categories, the echo probability of pulmonary hypertension is high.
If the TR velocity is >3.4m/s the echo probability of pulmonary hypertension is high.
Ventricular categories:
RV:LV basal diameter >1
IVS flattening (LV eccentricity index >1.1 in systole).
Pulmonary artery categories:
RVOT AT <105ms
Early diastolic PR velocity >2.2m/s
PA diameter >25mm
IVC categories:
IVC dilated (>2.1) with decreased inspiratory or quite collapse (>50% or >20%)
RA area >18cm2
How is pulmonary hypertension assessed by the ESC?
Pulmonary hypertension is unlikely if the TR Vmax is <2.8m/s, the PASP is < 36mmHg and there are no other characteristic
Pulmonary hypertension is possible if the TR Vmax is <2.8m/s, the PASP is <36mmHg and there are no other characteristics or the TR Vmax is 2.9-3.4m/s and the PASP is 37-50mmHg
Pulmonary hypertension is likely if the TR Vmax is >3.4m/s, the PASP is >50mmHg and there are no other characteristics.
Why is the RV difficult to assess?
Its crescent shape and trabeculae.
How is RV diameter, area and wall thickness assessed?
The RV size assessed in the modified A4C view by measuring the basal RV diameter (RVD1), mid-RV diameter (RVD2) and RV length (RVD3).
The RV size assessed in the PSAX view by measuring the RVOT diameter at the AV level (RVOT1), the RVOT diameter at the PV level (RVOT2) and the MPA diameter.
The RV wall thickness is assessed in the PLAX view by measuring the anterior RVOT wall at end-diastole. RVH is indicated by a RV wall thickness of >5mm.
The RV area is measured in the modified A4C view by tracing the endocardium at end-diastole and end-systole. The V volume can be estimated using the Simpon’s rule method or the area-length method (rare).
RV volume is rarely measured.
What are the BSE values for the assessment of RV size?
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How is RV systolic function assessed?
FAC is the percentage change in RV area. RV FAC= (EDA-ESA) / EDA x 100.
TAPSE measures the movement of the lateral tricuspid annulus during systole.
The Tei index measures systolic and diastolic myocardial function. Tei index= (a-b)/b= (IVCT+IVRT) / ET.
How is RV diastolic function assessed?
RV diastolic function is rarely assessed.
E:A ratio= (peak E wave velocity)/(peak A wave velocity) (TV inflow).
A tricuspid E:A ratio of <0.8 indicates RV diastolic dysfunction.
A tricuspid E:A ratio of 0.8-2.1 and E:E’ ratio of >6 indicates pseudonormal RV filling. A tricuspid E:A ratio of >2.1 and an E wave deceleration time of <120ms indicates restrictive RV filling.
