Pulmonology Coding Alert

Question: I was very interested in the article “5-Group System Helps You Classify Pulmonary Hypertension” in your last issue of Pulmonology Coding Alert and had a follow-up question for you: Our doctor indicated in an encounter note that a patient had “pre-capillary hypertension.” Can you explain what this means?

South Carolina Subscriber

Answer: Pulmonary hypertension (PH) can be classified as pre- or post-capillary, according to research from an April 23 study posted on the clinical decision support site,  www.uptodate.com. Pre-capillary PH (PAH) results from “a primary elevation of pressure in the pulmonary arterial system alone,” the report states. Post-capillary PH is caused by elevations of pressure in the pulmonary venous and pulmonary capillary systems (pulmonary venous hypertension.) What you may find is that some patients have mixed pre-and post-capillary features, the researchers advise.

If your pulmonologist’s clinical expertise lies in pulmonary hypertension, he may be able to clinically specify the type of PH the patient has, according to the characteristics of the disease and the associated five distinct “Clinical Groups.” 

Pre-capillary PH relates to a patient with mPAP >20 mmHg, PAWP ≤15 mmHg and PVR ≥3 WU; it is associated with the following Clinical Groups: 1 (PAH); 3 (PH due to lung diseases and/or hypoxia); 4 (PH due to pulmonary artery obstructions); and 5 (PH with unclear and/or multifactorial mechanisms). 

Post-capillary PH (characterized by mPAP >20 mmHg, PAWP >15 mmHg and PVR <3 WU) and combined pre- and post-capillary PH (characterized by mPAP >20 mmHg, PAWP >15 mmHg and PVR ≥3 WU) are associated with Clinical Groups 2 (PH due to left heart disease) and 5 (PH with unclear and/or multifactorial mechanisms).

ICD-10 codes applicable to each of the five Clinical Groups are as follows:

• Group 1: I27.0 (Primary pulmonary hypertension)
• Group 2: I27.22 (… due to left heart disease).
• Group 3: I27.23 (… due to lung diseases and hypoxia).
• Group 4: I27.24 (Chronic thromboembolic pulmonary hypertension)
• Group 5: I27.29 (Other secondary pulmonary hypertension)