← Section II · Valvular Heart Disease

II.H

Pulmonary Hypertension

17 cards

Notes

Definitions (2018 6th World Symposium / 2022 ESC/ERS)

Pulmonary hypertension: resting mean PAP > 20 mmHg on RHC.
Pre-capillary PH: mean PAP > 20 mmHg, PCWP ≤ 15 mmHg, PVR > 2 Wood units.
Post-capillary PH: mean PAP > 20 mmHg, PCWP > 15 mmHg.

WHO clinical classification (5 groups)

Pulmonary arterial hypertension (PAH) - idiopathic, heritable, drug/toxin, connective tissue disease, HIV, congenital shunts (Eisenmenger), portopulmonary.
PH due to left heart disease - HFrEF, HFpEF, valvular disease.
PH due to lung disease and/or hypoxia - COPD, ILD, sleep-disordered breathing.
Chronic thromboembolic PH (CTEPH).
Multifactorial / unclear - sarcoidosis, glycogen storage, hematologic disorders.

Echo estimation of PAP

PASP = 4·(TR V_max)² + RA pressure.
Mean PAP ≈ 4·(early diastolic PR velocity)² OR use Mahan (79 − 0.45 × AT).
PA end-diastolic pressure ≈ 4·(end-diastolic PR velocity)² + RAP.
Pulmonary vascular resistance estimate: PVR (Wood units) = (TR V_max / TVI_RVOT) × 10 + 0.16.

RA pressure from IVC

IVC diameter	Inspiratory collapse	RA pressure
≤ 2.1 cm	> 50 %	~3 mmHg (0–5)
Intermediate combination		~8 mmHg
> 2.1 cm	< 50 %	~15 mmHg

Echo signs suggesting PH

Elevated TR jet velocity (> 2.8 m/s at rest suggests PH probable).
RV dilation and hypertrophy (RV free-wall thickness > 5 mm end-diastole).
Flattening of the interventricular septum (D-shaped LV) in systole (pressure overload) or diastole (volume overload).
Enlarged RA (> 18 cm²).
Dilated pulmonary artery (> 25 mm).
Pulmonary acceleration time (AT) < 100 ms → elevated mean PAP.
Mid-systolic notching of PA flow → severe PAH.
Decreased TAPSE (< 17 mm).

Signs of severe PAH on PV M-mode

Diminutive / absent 'a'-wave.
Prolonged pre-ejection period.
Mid-systolic notching ('flying-W sign') - from transient reversal of RVOT-PA gradient due to poor PA compliance.

Assessing chronicity

Acute PE / cor pulmonale: TR jet velocity capped ~3.5 m/s (thin-walled RV can't generate higher pressure); wall motion abnormality of mid-RV free wall with apical sparing (McConnell's sign).
Chronic PAH: RVH develops (wall > 5 mm), and TR jet velocities can be markedly elevated.

Reversibility testing

Vasoreactivity testing (inhaled NO or IV epoprostenol) during RHC - if positive (mean PAP falls ≥ 10 mmHg to < 40 mmHg without decreased CO), the patient may respond to CCBs.

Cards

clozeII.H-001
Pulmonary hypertension is defined hemodynamically as a resting mean PA pressure > 20 mmHg on right-heart catheterization (2018/2022 guidelines).
basicII.H-002
Define pre-capillary vs post-capillary pulmonary hypertension.
→ Pre-capillary: mean PAP > 20, PCWP ≤ 15, PVR > 2 Wood units. Post-capillary: mean PAP > 20, PCWP > 15.
basicII.H-003
Name the five WHO groups of pulmonary hypertension.
→ 1) PAH (idiopathic, heritable, drug/toxin, CTD, HIV, congenital, portopulm). 2) Left-heart disease. 3) Lung disease/hypoxia. 4) CTEPH. 5) Multifactorial (sarcoid, hematologic, etc).
basicII.H-004
State the ASE formula for estimating PASP from a TR jet.
→ PASP = 4·(TR peak velocity)² + right atrial pressure. RA pressure is estimated from IVC size and collapsibility.
basicII.H-005
Formula for estimating MEAN pulmonary artery pressure from a PR jet?
→ Mean PAP ≈ 4·(early diastolic PR velocity)². Alternative: Mahan formula, mean PAP ≈ 79 − 0.45 × AT (pulmonary acceleration time in ms).
basicII.H-006
Simplified echo estimate of pulmonary vascular resistance (PVR)?
→ PVR (Wood units) ≈ (TR peak velocity / VTI_RVOT) × 10 + 0.16. A ratio > 0.275 correlates with PVR > 2 Wood units.
basicII.H-007
Name three 2-D or M-mode findings that suggest chronic pulmonary hypertension.
→ RV dilation/hypertrophy (free wall > 5 mm end-diastole), septal flattening (D-shaped LV), enlarged RA (> 18 cm²), dilated PA (> 25 mm), decreased TAPSE (< 17 mm), mid-systolic notching of PA flow.
basicII.H-008
How does septal flattening timing distinguish RV pressure from RV volume overload?
→ Pressure overload (e.g., PAH): septal flattening in SYSTOLE (D-shaped LV in systole). Volume overload (e.g., ASD, severe TR): septal flattening in DIASTOLE.
basicII.H-009
What is McConnell's sign and what does it suggest?
→ Akinesis or hypokinesis of the RV free wall with sparing of the apex (which contracts vigorously due to LV tethering). Suggests ACUTE pulmonary embolism / RV pressure overload rather than chronic PAH.
basicII.H-010
Why is the estimated PASP typically capped around 60–70 mmHg in ACUTE massive PE despite severe RV strain?
→ The unprepared, thin-walled RV cannot generate high pressures acutely (typically peaks ~50–60 mmHg). Markedly elevated PASP (> 60–70 mmHg) suggests chronic PH rather than acute PE.
basicII.H-011
Define a positive vasoreactivity test on right-heart catheterization in PAH.
→ A ≥ 10 mmHg fall in mean PAP to an absolute value < 40 mmHg, without a fall in cardiac output, during inhaled NO or IV epoprostenol. A positive test predicts response to calcium channel blocker therapy.
basicII.H-012
What pulmonary acceleration time cutoff strongly suggests elevated mean PAP?
→ AT < 100 ms. Normal ≥ 130 ms. Measured from onset of pulmonary ejection to peak velocity on PW Doppler in the RVOT.
basicII.H-013
What is the significance of a right ventricular free-wall thickness > 5 mm on echo?
→ RV hypertrophy — indicates chronic RV pressure overload (chronic PAH, chronic PS). NOT expected in acute pulmonary embolism (which has a thin-walled RV).
basicII.H-014
State the WHO Group 1 vasodilators used in PAH-specific therapy.
→ 1) Phosphodiesterase-5 inhibitors (sildenafil, tadalafil). 2) Endothelin receptor antagonists (bosentan, ambrisentan, macitentan). 3) Prostacyclin analogues (epoprostenol, treprostinil, iloprost). 4) Soluble guanylate cyclase stimulator (riociguat — also for CTEPH).
basicII.H-015
What noninvasive imaging modality is preferred for chronic thromboembolic PH (CTEPH) diagnosis?
→ V/Q scan — highly sensitive for CTEPH (mismatched perfusion defects). CT pulmonary angiography confirms and characterizes anatomy for potential pulmonary endarterectomy.
basicII.H-016
What is the definitive treatment for chronic thromboembolic PH?
→ Pulmonary thromboendarterectomy (PTE) — surgical removal of organized thrombi from the pulmonary arteries. Riociguat and balloon pulmonary angioplasty are alternatives for inoperable disease.
basicII.H-017
How does exercise stress echo help evaluate suspected pulmonary hypertension?
→ Exercise-induced increase in TR jet velocity > 3.4 m/s (or > 40 mmHg PASP at low workload) can identify latent or exercise-induced PH — particularly useful in HFpEF and connective tissue disease.