Pulmonary Embolism

PE is the third most common cause of death from cardiovascular disease after heart attack and stroke [13]. In the UK, Hospital Episode Statistics show that there were more than 28,000 cases in a recent 1 year period (2010-11) [14]. An international registry of PE patients showed that the mortality rate for acute PE exceeds 15% in the first 3 months after diagnosis and surpasses that of myocardial infarction [15]. Death from PE most commonly occurs as a result of progressive right ventricular failure resulting in cardiovascular collapse [16]. Survivors of acute PE remain at risk for CTPH [17].

Major risk factors for PE [13]
Idiopathic, primary, and unprovoked
No apparent cause
Old age (>65 years)
Long-haul travel
Associated with thrombophilia (e.g. factor V Leiden or prothrombin gene mutation)
Obesity
Cigarette smoking
Hypertension
Metabolic syndrome
Air pollution
Secondary and provoked
Immobilisation
Recent surgery
Trauma
Oral contraceptives, pregnancy, or postmenopausal hormonal replacement
Cancer
Acute medical illness (e.g. pneumonia, congestive heart failure)

Chronic thromboembolic pulmonary hypertension (CTPH)

CTPH, defined as a mean pulmonary artery pressure greater than 25 mm Hg that persists for 6 months after diagnosis of PE, is an important long-term morbidity associated with PE and occurs in 2–4% of patients after acute PE [17]. The diagnosis can be overlooked because many patients do not have a history of clinically overt PE [17]. CTPH results in disabling dyspnoea, both at rest and on exertion. Life expectancy is often shortened and patients frequently die of sudden cardiac death. Death is usually due to progressive pulmonary hypertension culminating in right ventricular failure.