ICD-10 Code I27.21 – Secondary pulmonary arterial hypertension (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code I27.21 – Secondary pulmonary arterial hypertension
What it is
I27.21 identifies pulmonary arterial hypertension that occurs secondary to another condition. Use it when documentation states the pulmonary hypertension is causally linked to an underlying disease or disorder.
Clinical signs
Clinical features vary; refer to documentation. Commonly recorded findings include exertional dyspnea, fatigue, chest discomfort, syncope, or signs of right heart strain when pulmonary hypertension is confirmed.
When to use this code
Use this code when the provider documents secondary pulmonary arterial hypertension, or pulmonary arterial hypertension due to a specified cause. It is appropriate when the record supports an underlying condition and the relationship is stated or clearly implied. Check documentation for the causal disorder.
Do not use for
Do not use it for primary or idiopathic pulmonary hypertension, or for nonspecific pulmonary hypertension without a documented secondary cause. If the record does not support pulmonary arterial involvement, check documentation.
Coding tip
Code the underlying condition first when instructed by the record and official guidance, and verify that “secondary” or an equivalent causal link is documented.