Pulmonary Hypertension | Deranged Physiology

In the past papers, pulmonary hypertension crops up now and then as a sideshow to some other major problems, or as a comorbidity to discuss. For instance, in Question 12 from the second paper of 2017 the patient has among other things pulmonary hypertension, and the candisates were asked to discuss their periop Question 2 from the second paper of 2015 asks the candidates to identify the causes of pulmonary hypetension. The update article by Siomonneau (2013) is an excellent resource for this answer, and is used to generate the table offered below. For a more thorough review of this disease process, one may look at the massive 2015 ESC/ERS Guidelines.

Classification of pulmonary hypertension

The list used by the college answer is the updated 2013 Dana Point classification, which can be found in the Siomonneau article in Table 1. The objective of such a clasification was to join into groups pulmonary hypertensive diseases which share "similar pathological findings, similar hemodynamic characteristics and, similar management".

In brief, there are 5 major groups of disease which fall under the pulmonary hypertension heading:

Pulmonary arterial hypertension
Pulmonary hypertension due to left heart disease
Pulmonary hypertension due to lung disease or hypoxia
Pulmonary hypertension due to chronic PE
Pulmonary hypertension due to "unclear multifactorial mechanisms"

In detail:

Classification of Pulmonary Hypertension

Pulmonary Arterial Hypertension	Idiopathic Herediary or congenital Familial PAH BMPR2 mutations (a member of the transforming growth factor β signaling family) Congenital systemic-to-pulmonary shunts Eisenmenger syndrome Drug and toxin induced Definite association: aminorex, fenfluramine, dexfenfluramine, toxic rapeseed oil Possible association: cocaine, phenylpropanolamine, St Johns Wort, chemotherapy agents, SSRIs Associated with connective tissue disease Systemic sclerosis SLE Sjogren syndrome polymyositis rheumatoid arthritis Associated with HIV infection clinical, hemodynamic, and histologic characteristics similar to those seen in idiopathic PAH Portopulmonary hypertension 2% to 6% of patients with portal hypertension have PAH Pulmonary vascular resistance (PVR) is usually normal in these cases
Left heart disease	LV failure Mitral valve disease Congenital or idiopathic cardiomyopathies, eg. HOCM
Lung disease or hypoxia	Idiopathic pulmonary fibrosis (by virtue of fibrosis) Chronic hypoxia: Alveolar hypoxia as a result of lung disease, eg. COPD or pulmonary fibrosis Alveolar hypoxia due to impaired control of breathing (eg. OSA)\ Alveolar hypoxia due to residence at high altitude
Thromboembolism	obstruction of pulmonary arterial vessels by thromboemboli, tumors, or foreign bodies
Pulmonary hypertension due to unclear or multifactorial aetiologies	polycythemia vera essential thrombocythemia chronic myeloid leukemia Chronic haemolytic anaemia sickle cell disease (SCD) thalassemia hereditary spherocytosis stomatocytosis microangiopathic hemolytic anemia sarcoidosis Langerhans histiocytosis glycogen storage diseases Gaucher disease mediastinal fibrosis Schistosomiasis Embolic obstruction of pulmonary arteries by schistosoma eggs local vascular inflammation as a result of impacted schistosoma eggs

References

Simonneau, Gérald, et al. "Updated clinical classification of pulmonary hypertension." Journal of the American College of Cardiology 54.1s1 (2009): S43-S54.

Simonneau, Gerald, et al. "Updated clinical classification of pulmonary hypertension." Journal of the American College of Cardiology 62.25 (2013): D34-D41.

Galiè, Nazzareno, et al. "2015 ESC/ERS Guidelines for the diagnosis and treatment of pulmonary hypertension." European heart journal (2015): ehv317.

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