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TOPIC 9 Pulmonary vascular disorders

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

Algorithm for investigation suspected pulmonary hypertension (Figure 9.1)

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

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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TOPIC 9 Pulmonary vascular disorders

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