Pulmonary HTN and pulmonary embolism Flashcards
Definition of pulmonary HTN
An increase in mean pulmonary arterial pressure (PAP) >25mmHg
General classification of pulmonary HTN
Pulmonary arterial hypertension (PAH)
- Idiopathic PAH
- HEritable
- Drugs and toxins induces
- Associated with APAH
- Persistent pulmonary HTN of the newborn
Pulmonary HTN due to left heart disease
Pulmonary HTN due to lung diseases and/or hypoxaemia
- Chronic obsructive pulmonary disease
- Interstitial lung disease
- Other pulmonary disease with mixed restrictive and obstructive pattern
- Sleep-disorder breathing
- Alveolar hypoventilation disorders
- Chronci exposure to high altitude
- Developmental abnormalities
Chronic thromboembolic pulmonary HTN
_PH with unclear and/or multifactoral mechanisms _
PCWP
Wedge pressure
Drugs and toxins that cause PAH
Definitely
- Aminorex
- Fenfluramine
- Detenfluramine
- Toxic rapeseed oil
- Benfluorex
Likely
- Amphertamines
- Methamphetamines
Pulmonary hypertension (PH) characteristics and clinicla groups
Mean PAP >25mmHg
All clinical groups.
Pre-capillary PH charcteristics
- Mean PAP >25mmHg
- PWP <15mmHg
- CO normal or reduced
Pre-capillary PH clinical group(s)
- Pulmonary arterial HTN
- PH due to lung diseases
- Chronic thromboembolic PH
- PH with unclear and/or multifactoral mechanisms
Postcapillary PH characteirtsics
(caused by left heart disease)
- Mean PAP >25mmHg
- PWP >15mmHg
- CO normal or reduced
Post-capillary PH clinical groups
PH due to left heart disease
Passive PH
TPG <12mmHg
Reactive PH
May be additional cardiac remodeling
TPG >12mmHg
Vasoresponders
Patients who respond to calcium channel agonists - pressure in pulmonary circulation drops to a certain level, and CO remains the same.
Only about 10% respond to calcium channel antagonists.
Agents for testing vasoreactivity
- IV epaprostenol
- iNO
- Adenosine IV
- Iloprost inh
- Sildenafil
World burden PH
Schistosomiasis: infectious organism that lays its eggs in the pulmonary circulation and obliterates it, causing destruction of the vascular bed, and thus high resistance.
High altitude: >2500m, chronically exposed to hypoxia, leads to vasoconstriction adn elevated pulmonary pressures - develop RHF.
Chronic inhereted: sickle cell disease, thalassaemia
HIV: 1% develop PH
Cardia diseases: high LAP and high elevation in pulmonary pressure.
- Rheumatic valvular disease
- Congenital heart disease
- Endomyocardial fibrosis
Pathogenesis of PH
Vasoconstriction
- Often triggered by hypoxia
Endothelial dysfunction: not normal signaling between endothelium and smooth muscle.
- High flow or pressure (shunts)
- Direct toxins (such as weight loss drugs)
- Intimal proliferation (due to genetic predisposition)
Smooth muscle
- Hyperplasia
- Hypertrophy
- Increased matrix deposition and fibroblast proliferation - walls become very stiff and non-compliant.
Thrombosis in situ
- Due to obliteration of the vascular bed
- Hence treatment with anticoagulants
Insult leads to vascular injury resulting in:
- Decreased NO and prostacyclin, which are vasodilators
- Upregulation of endothelin - potent vasoconstrictor
- Upregulation of thromboxane - potent vasoconstriction and platelet adherence
Plexiform lesion
Pathopneumonic lesion in PH.
Uncontrolled cell proliferation, vascular outgrowth and failure of apoptosis - can be seen histologically.
Signs and symptoms of PH
These are signs and symptoms of inadequate cardiac output:
- Disease onset: no early symptoms of PH
- First symptoms: progressive dyspnea on exertion, fatigue, palpitations, chest pain, dizziness, syncope, coughing.
- End stage symptoms: symptoms and signs of RHF, edema, ascites.
Physical examination fidings in PH
- Loud pulmonic valve closure (P2)
- Graham-Steele murmur
- Pulmonic regurgitation
- Right sided fourth heart sound
- High pitched, pre-systolic sound
- Resistance in RV filling due to reduced compliance (hypertrophy)
- RV heave
- Jugular venous distention
- Hepatomegaly
- Peripheral edema, ascites.
Why is diagnosis of PH made late in the disease?
Due to:
- Under-recognition
- Non-specific symptoms
- Confusion with other conditions
- iPAH is a diagnosis of exclusion
Who should be screened?
Individuals in high risk populations
- Family history of iPAH
- CT disease
- Pulmonary embolism
- Congenital heart disease
Idiopathic PAH epidemiology
- Young
- F:M 1.8:1
- 6-10% familial
- 2q33 BMPR2 gene
- Incidence 1-2/million
- Prevalence 15-20/million
- iPAH and associated PAH equally distributed
- Prevalence 40/million
- Under-diagnosis and under-reported
Echocardiography in PH
- Mild PH 36-50mmHg (eRVSP) or TR 2.8-3.4 m/s
- RV size and function
- LV diastolic and systolic function
- Valve morphology and function
- Shunts using ‘bubble’ study
- ePVR
- Pericardial effusion
Pulmonary function testing (PFTs)
