Table 1.
A small subset of the Multi-Level Clinical Classification Tree with International Classification of Diseases, Ninth Revision (ICD-9) codes associated with a specific level.
| 07 | Diseases of the Circulatory System |
| 07.01 | Hypertension |
| 07.01.02 | Hypertension with Complications and Secondary Hypertension |
| 07.01.02.01 | Hypertensive Heart and/or Renal Disease (402.00–404.93) |
| 07.01.02.02 | Other Hypertensive Complications (405.01–405.99,437.2) |
| 07.02 | Diseases of The Heart |
| 07.02.01 | Heart Valve Disorders |
| 07.02.01.02 | Nonrheumatic Mitral Valve Disorders (424.0) |
| 07.02.01.03 | Nonrheumatic Aortic Valve Disorders (424.1) |
| 07.02.01.04 | Other Heart Valve Disorders (424.2, 424.3, 785.2, 785.3) |
| 07.02.02 | Peri; Endo; and Myocarditis; Cardiomyopathy (Except that Caused by TB or STD) |
| 07.02.02.01 | Cardiomyopathy (425.0–425.9) |
| 07.02.03 | Acute Myocardial Infarction (410.0–410.92) |
| 07.02.04 | Coronary Atherosclerosis and Other Heart Disease |
| 07.02.04.01 | Angina Pectoris (413.0–413.9) |
| 07.02.04.02 | Unstable Angina (Intermediate Coronary Syndrome) (411.1) |
| 07.02.04.03 | Other Acute and Subacute Forms of Ischemic Heart Disease (411.0, 411.8–411.89) |
| 07.02.04.04 | Coronary Atherosclerosis (414.05) |
| 07.02.04.05 | Other Forms of Chronic Heart Disease (414.8, 414.9) |
| 07.02.04.00 | Other (414.06) |