9: Pulmonary vascular disorders

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TOPIC 9 Pulmonary vascular disorders

Topic Contents

Pulmonary hypertension 89

Definition 89
Incidence 89
Causes and Classification (ESC Guidelines 2004) 89
Investigations 90
Commonly used vaso-active dugs for vasodilator study drug 91
Algorithm for investigation suspected pulmonary hypertension 91
Management 91
Pulmonary thromboembolism 93

Risk factors 93
Investigations 94
Treatment 94

Pulmonary hypertension

Definition

Mean pulmonary artery pressure (PAP):

> 25 mmHg at rest
> 30 mmHg with exercise.

Incidence

Estimated at 500–1000 new cases annually
Approximately 2–3 per million per year with a prevalence of 15 per million
Occurs in men, women and children of all ages
Most common in females between 20 and 40 years old (M:F 1:2)
Rare in children, but sometimes seen in infants born with valvular defects.

Causes and Classification (ESC Guidelines 2004)

1. Pulmonary arterial hypertension (PAH)

1.1. Idiopathic pulmonary arterial hypertension (IPAH)
1.2. Familial pulmonary arterial hypertension (FPAH)
1.3. Associated with APAH

1.3.1. Connective tissue disease
1.3.2. Congenital systemic to pulmonary shunts
1.3.3. Portal hypertension
1.3.4. HIV infection
1.3.5. Drugs and toxins
1.3.6. Other

1.4. Associated with significant venous or capillary involvement

1.4.1. Pulmonary veno-occlusive disease (PVOD)
1.4.2. Pulmonary capillary haemangiomatosis

1.5. Persistent pulmonary hypertension of the newborn (PPHN)

2. Pulmonary hypertension associated with left heart disease

2.1. Left-sided atrial or ventricular heart disease
2.2. Left-sided valvular heart disease

3. Pulmonary hypertension associated with lung respiratory disease/hypoxia

3.1. Chronic obstructive pulmonary disease
3.2. Interstitial lung disease
3.3. Sleep disordered breathing
3.4. Alveolar hypoventilation disorders
3.5. Chronic exposure to high altitude
3.6. Developmental abnormalities

4. Pulmonary hypertension due to chronic thrombotic and/or embolic disease

4.1. Thromboembolic obstruction of proximal pulmonary arteries
4.2. Thromboembolic obstruction of distal pulmonary arteries
4.3. Non-thrombotic pulmonary embolism (tumour, foreign material)

5. Miscellaneous (sarcoid, histiocytosis X)

Investigations

Electrocardiogram
Nocturnal oxygen saturation (>96%)
Chest radiograph
Respiratory function tests
Echocardiogram
Ventilation perfusion scan
High-resolution CT scan
Helical CT with pulmonary angiography
Blood tests
Haematology

Full blood count
ESR
Clotting screen
Thrombophilia screen
Protein C
Protein S
Lupus anticoagulant
Antithrombin III
Leiden factor V
Abnormal haemoglobin
Blood group

Biochemistry

Urea and electrolytes
Liver function tests
CRP
Serum ACE
Thyroid function
Arterial blood gases
Autoimmune screen
Anti-nuclear factor
Anti-smooth muscle
Anti-centromere
Anti-SCL70
Anti-RNP
Anti-phospholipid
Anti-mitochondria
Anti-parietal
Microbiology
Hepatitis B status
Hepatitis C status
VDRL/TPHA
HIV
Viral titres
CMV, EBV
H simplex
Toxoplasma, Pneumocystis
Aspergillus screen

Right heart catheterization (see Chapter 5 for normal chamber pressures)

Right artial pressure
Pulmonary arterial pressure (systolic, diastolic and mean)
Pulmonary capillary wedge pressure
Cardiac output (thermodilution or Fick methods)
Systemic vascular resistance
Arterial and mixed venous oxygen saturation
Acute vasodilator testing

Commonly used vaso-active dugs for vasodilator study drug

Table 9.1 Commonly used vaso-active dugs for vasodilator study

image

Algorithm for investigation suspected pulmonary hypertension (Figure 9.1)

image

Figure 9.1 Diagnostic algorithm for the investigation of suspected pulmonary hypertension. ALK-1, activin-receptor-like kinase; ANA, anti-nuclear antibodies; BMPR2, bone morphogenetic protein receptor 2; CHD, congenital heart disease; CMR, cardiac magnetic resonance; CTD, connective tissue disease; Group, clinical group; HHT, hereditary haemorrhagic telangiectasia; HIV, human immunodeficiency virus; HRCT, high-resolution computed tomography; LFT, liver function tests; mPAP, mean pulmonary arterial pressure; PAH, pulmonary arterial hypertension; PCH, pulmonary capillary haemangiomatosis; PFT, pulmonary function test; PH, pulmonary hypertension; PVOD, pulmonary veno-occlusive disease; PWP, pulmonary wedge pressure; RHC, right heart catheterization; TEE, transoesophageal echocardiography; TTE, transthoracic echocardiography; US, ultrasonography; V/Q, ventilation/perfusion lung scan.

Adapted with permission from European Heart Journal 2009; 30: 2493–2537.

Management

Anticoagulants
Diuretics
Calcium channel blockers
Endothelin receptor antagonist
Prostacyclin
Oxygen
Transplantation

Pulmonary thromboembolism

Risk factors

1. Major risk factors (relative risk 5–20):

a. Surgery*

Major abdominal/pelvic surgery
Hip/knee replacement
Postoperative intensive care

b. Obstetrics

Late pregnancy
Caesarean section
Puerperium

c. Lower limb problems

Fracture
Varicose veins

d. Malignancy

Abdominal/pelvic
Advanced/metastatic

e. Reduced mobility

Hospitalization
Institutional care

f. Miscellaneous

Previous proven VTE

2. Minor risk factors (relative risk 2–4):

a. Cardiovascular

Congenital heart disease
Congestive cardiac failure
Hypertension
Superficial venous thrombosis
Indwelling central vein catheter

b. Oestrogens

Oral contraceptive
Hormone replacement therapy

3. Miscellaneous

COPD
Neurological disability
Occult malignancy
Thrombotic disorders
Long-distance sedentary travel
Obesity
Other (inflammatory bowel disease, nephrotic syndrome, chronic dialysis, myeloproliferative disorders, paroxysmal nocturnal haemoglobinuria).

Investigations (Figure 9.2)

Chest X ray
D-dimer – normal range 0–218 ng/ml
CT pulmonary angiogram
Isotope lung scan if CTPA unavailable or equivoval
Lower limb ultrasound if indicated
image

Figure 9.2 Investigation and treatment algorithm for management of pulmonary emboli.

Treatment

Thrombolysis (alteplase 50 mg) in massive PE
Heparin (low-molecular-weight or unfractionated if reversal a possibility)
Oral anticoagulation (at least 6 months)

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