I27.0
Primary pulmonary hypertension
I27.0 (also written I270) is a billable ICD-10-CM diagnosis code for primary pulmonary hypertension. It is part of the FY2027 code set, effective October 1, 2026. It is one of the 17 codes in category I27 (Other pulmonary heart diseases). The Alphabetic Index lists it under 14 entries. Its coding notes include 4 Excludes1 entries and 10 Excludes2 entries.
Excludes1
Not coded here. The listed conditions generally should not be reported together.
Excludes2
Not included here. Both codes may be reported if the patient has both conditions.
Also from chapter/block level (10 notes)
- certain conditions originating in the perinatal period (P04-P96)
- certain infectious and parasitic diseases (A00-B99)
- complications of pregnancy, childbirth and the puerperium (O00-O9A)
- congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
- endocrine, nutritional and metabolic diseases (E00-E88)
- injury, poisoning and certain other consequences of external causes (S00-T88)
- neoplasms (C00-D49)
- symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
- systemic connective tissue disorders (M30-M36)
- transient cerebral ischemic attacks and related syndromes (G45.-)
Care settings
How CMS programs treat this code. These are CMS claim edits and list entries, not coverage or eligibility rules.
Home Health Primary
Accepted as the primary (principal) diagnosis on a home health claim. The Home Health Grouper assigns it to the MMTA - Cardiac and Circulatory clinical group.
Source: CMS Home Health Grouper Software v07.2.26, effective October 1, 2026Hospital CC
Counts as a complication or comorbidity (CC) when reported as a secondary diagnosis on an inpatient claim. It does not count when the principal diagnosis is one of the 21 codes in its exclusion list. Some MS-DRGs also ignore a CC or MCC that defines the DRG.
Source: CMS MS-DRG Definitions Manual v44, effective October 1, 2026, Appendix CIPF Comorbidity
On the CMS IPF comorbidity list.
| Comorbidity category | Factor |
|---|---|
| Cardiac Conditions | 1.04 |
Inclusion terms
Conditions classified to this code.
- Heritable pulmonary arterial hypertension
- Idiopathic pulmonary arterial hypertension
- Primary group 1 pulmonary hypertension
- Primary pulmonary arterial hypertension
Alphabetic Index terms
Terms the official Alphabetic Index lists for this code. 14 entries
- Arrillaga-Ayerza syndrome (pulmonary sclerosis with pulmonary hypertension)
- Arteriosclerosis, arteriosclerotic (diffuse) (obliterans) (of) (senile) (with calcification), pulmonary (idiopathic)
- Ayerza's disease or syndrome (pulmonary artery sclerosis with pulmonary hypertension)
- Cardiopathia nigra
- Disease, diseased, Ayerza's (pulmonary artery sclerosis with pulmonary hypertension)
- Disease, diseased, heart (organic), black
- Disease, diseased, pulmonary, hypertensive (vascular), primary (idiopathic)
- Hypertension, hypertensive (accelerated) (benign) (essential) (idiopathic) (malignant) (systemic), lesser circulation
- Hypertension, hypertensive (accelerated) (benign) (essential) (idiopathic) (malignant) (systemic), pulmonary, primary (idiopathic)
- Sclerosis, sclerotic, pulmonary, artery
- Syndrome, Arrillaga-Ayerza
- Syndrome, Ayerza (-Arrillaga)