Pulmonary Embolism: True/False Analysis
Statement 1: Usually associated with thrombosis in deep veins of legs or pelvic veins
TRUE - Deep vein thrombosis and pulmonary embolism are clinical manifestations of the same entity, venous thromboembolic disease 1. The vast majority of pulmonary emboli originate from thrombi in the deep veins of the lower extremities or pelvic veins 2. The European Society of Cardiology guidelines explicitly state that DVT and PE are common causes of illness and death, representing different presentations of the same underlying thrombotic process 1.
Statement 2: May cause sudden death
TRUE - Pulmonary embolism can be immediately fatal and is a well-established cause of sudden death 1. The European Society of Cardiology reports that in approximately 25% of patients, the first manifestation of PE is sudden-unexpected death 3. Mortality in untreated PE is approximately 30%, and the ICOPER study revealed a cumulative 3-month mortality as high as 17.5% 1. A forensic autopsy study found that PE represented 4.3% of all sudden deaths, with 78% of cases occurring at home or during transfer to healthcare centers 3. Right ventricular failure due to acute pressure overload is the primary cause of death in severe PE 1.
Statement 3: Often results in pulmonary infarction
FALSE - Pulmonary infarction is actually uncommon in pulmonary embolism 1. The European Society of Cardiology guidelines explicitly state that "even if they do not affect haemodynamics, small distal emboli may create areas of alveolar haemorrhage resulting in haemoptysis, pleuritis, and pleural effusion, which is usually mild. This clinical presentation is known as 'pulmonary infarction'" 1. However, a forensic study found pulmonary infarction was associated with PE in only 6% of cases 3. The effect on gas exchange from pulmonary infarction is normally mild, except in patients with pre-existing cardiorespiratory disease 1.
Statement 4: Is a cause of pulmonary hypertension
TRUE - Pulmonary embolism is definitively a cause of pulmonary hypertension, both acutely and chronically 1. The European Society of Cardiology states that "in the long-term, there is the risk of developing pulmonary hypertension from recurrent embolism or the absence of reperfusion of the pulmonary vasculature" 1. Chronic thromboembolic pulmonary hypertension develops in approximately 3.8% of patients within 2 years after an initial PE episode 4. Acutely, pulmonary artery pressure increases when >30-50% of the total cross-sectional area of the pulmonary arterial bed is occluded by thromboemboli 1, 5.
Statement 5: Produces strain on the left side of the breast
FALSE - Pulmonary embolism produces strain on the RIGHT side of the heart, not the left 1. The pathophysiology clearly demonstrates that acute PE causes right ventricular failure due to acute pressure overload 1. The abrupt increase in pulmonary vascular resistance results in RV dilation and dysfunction 1, 5. While the interventricular septum bows leftward and impedes LV filling secondarily, the primary hemodynamic strain is on the right ventricle 1, 5. The European Society of Cardiology emphasizes that "acute RV failure is a critical determinant of clinical severity and outcome in acute PE" 1.