Pulmonary HTN and pulmonary embolism Flashcards Preview

CAM201 Clinical Skills > Pulmonary HTN and pulmonary embolism > Flashcards

Flashcards in Pulmonary HTN and pulmonary embolism Deck (23):

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 



Wedge pressure


Drugs and toxins that cause PAH


  • Aminorex
  • Fenfluramine
  • Detenfluramine
  • Toxic rapeseed oil
  • Benfluorex


  • 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)

  1. Pulmonary arterial HTN
  2. PH due to lung diseases
  3. Chronic thromboembolic PH
  4. 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



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


  • 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)