I27.21

HCC Category Mapping

What This Code Means

High blood pressure in the lung arteries caused by conditions affecting the right side of the heart or lung blood vessels directly.

Coding Tips

• •Document the underlying cause (such as connective tissue disease, HIV, or drug-induced) as this affects treatment and prognosis
• •This code requires documentation of the secondary etiology; link it with the appropriate causal condition code

Clinical Significance

Secondary pulmonary arterial hypertension indicates elevated pulmonary pressures caused by identifiable underlying conditions such as connective tissue disease, HIV infection, or drug exposure. This represents complex multi-system disease requiring targeted therapy and close monitoring. Accurate capture reflects the true disease burden.

Documentation Requirements

• ✓Provider diagnosis of secondary pulmonary arterial hypertension
• ✓Identified underlying cause documented (connective tissue disease, HIV, drugs, portal hypertension)
• ✓Right heart catheterization or echocardiographic evidence of pulmonary hypertension
• ✓Causal relationship between the underlying condition and pulmonary hypertension documented
• ✓Current treatment targeting both the pulmonary hypertension and the underlying cause

Commonly Confused Codes