Critical Care Medicine-Pulmonary Disorders>>>>>Thromboembolic Disease and Hemoptysis
Question 3#

A 40-year-old female is admitted to the intensive care unit with worsening shortness of breath. She states that she had a clot in her lung “a long time ago” for which she “took blood thinners for a few months.” Her initial transthoracic echocardiogram reveals enlarged right-sided chambers with severe tricuspid regurgitation and a large thrombus in the pulmonary artery with severe pulmonary hypertension.

This patient is MOST likely to belong to which of the groups of the World Health Organization clinical classification of pulmonary hypertension. 

A. Group 1
B. Group 2
C. Group 3
D. Group 4
E. Group 5

Correct Answer is D


Correct Answer: D

The World Health Organization clinical classification of pulmonary hypertension categorizes this diagnosis into groups based on similarities in pathophysiology, clinical presentation, and therapeutic measures. The five broad groups are as follows: 

  1. Pulmonary arterial hypertension (Group 1)—Pulmonary hypertension that is idiopathic; drug-, toxin-, or infection-induced; and those that are associated with systemic diseases fall into this category.
  2. Pulmonary hypertension due to left heart disease (Group 2)—Pulmonary hypertension arising from left heart disease, be it atrial, ventricular, or valvular falls under this category. This is probably the most common etiological class for pulmonary hypertension. Left-sided disease leading to elevated left atrial pressure results in back pressure into the pulmonary vasculature. Over time, increases in pulmonary vasomotor tone and pulmonary vascular remodeling result in worsening pulmonary arterial pressures.
  3. Pulmonary hypertension due to lung disease (Group 3)—Pulmonary hypertension as a result of intrinsic lung disease and/or hypoxia falls under this category.
  4. Chronic thromboembolic pulmonary hypertension (CTEPH) (Group 4)—Thromboemboli either forming in or traveling to the lung resulting in pulmonary hypertension fall under this group.
  5. Pulmonary hypertension with unclear or multifactorial mechanisms (Group 5)—Disorders wherein the mechanism of pulmonary hypertension is poorly understood fall under this category. A few of these include sarcoidosis, Langerhans cell histiocytosis, and certain anemias.

Given the clinical presentation, this patient seems to have a large clot in the pulmonary artery with enlarged right-sided chambers and pulmonary hypertension. She most likely has CTEPH and belongs to group 4. 


  1. Simonneau G, Robbins IM, Beghetti M, et al. Updated clinical classification of pulmonary hypertension. J Am Coll Cardiol. 2009; 54:S43-S54.
  2. Simonneau G, Gatzhoulis M, Adatia I, et al. Updated clinical classification of pulmonary hypertension. J Am Coll Cardiol. 2013;62(25):D34-D41.