Koen Nieman, MD
NPI 1144778143ActiveIndividual· Internal Medicine, Cardiovascular Disease· Stanford, CA
Internal Medicine, Cardiovascular Disease (MD) with Stanford Health Care, practicing in Stanford, California. In 2024 Medicare paid $107,671 for 1,988 patients, and Part D covered 271 of their prescriptions, 88% of them generic. Heartflow, Inc. was the largest of 3 companies reporting payments in 2025, $337.89 in all, mostly food and beverage. Lists El Camino Health and 2 other hospitals as hospital affiliations.
Overview
| NPI | 1144778143 |
|---|---|
| Status | Active |
| Entity type | Individual |
| Credential | MD |
| Sole proprietor | No |
| NPI issued | Sep 19, 2016 |
| Last updated in NPPES | Apr 24, 2024 |
| Certified by provider | Apr 24, 2024 |
Specialties and licenses
| Taxonomy | Code | License | State |
|---|---|---|---|
| Internal Medicine, Cardiovascular Disease Primary | 207RC0000X | A174597 | CA |
| Specialist | 174400000X | 29048831401 | ZZ |
Exclusion screening
| List | Result | Details |
|---|---|---|
| HHS-OIG LEIE · Nov 10, 2026 | No match | Checked by NPI and by name + state |
| North Carolina Medicaid · Nov 11, 2026 | No match | — |
| New York OMIG · Nov 11, 2026 | No match | — |
| Ohio Medicaid · Nov 11, 2026 | No match | — |
| Pennsylvania Medicheck · Nov 11, 2026 | No match | — |
| Washington HCA · Nov 11, 2026 | No match | — |
Official OIG search · How matching works ·Bulk check a roster
Medicare
| Enrollment (PECOS) | Enrolled Practitioner - Cardiovascular Disease (Cardiology) (CA) |
|---|---|
| Accepts assignment | Yes (participating) |
Medicare services in 2024
| Medicare patients | 1,988 |
|---|---|
| Services billed | 2,889 across 29 procedure codes |
| Paid by Medicare | $107,671 |
Part D prescriptions in 2024
| Prescriptions (claims) | 271 · 702 30-day fills |
|---|---|
| Patients | 48 |
| Total drug cost | $49,637 |
| Generic share | 88% of claims |
Education and affiliations
| Graduation year | 1998 |
|---|---|
| Medicare specialty | Cardiovascular Disease (Cardiology) |
| Telehealth | Offers telehealth |
Medical group
- Stanford Health CareStanford, CA · 3,122 clinicians
Hospital affiliations
- El Camino HealthMountain View, CA
- Peninsula Medical CenterBurlingame, CA
- Stanford Health CareStanford, CA
Industry payments (Open Payments)
- 2025$337.89 · 5 payments from 3 companies
- 2024$5,011 · 7 payments from 4 companies
Top paying companies in 2025
| Company | Amount | Payments |
|---|---|---|
| Heartflow, Inc. | $156.69 | 2 |
| Ge Healthcare | $100.33 | 1 |
| Siemens Medical Solutions USA, Inc. | $80.87 | 2 |
What the 2025 payments were for
- Food and Beverage$291.02 · 4 payments
- Travel and Lodging$46.87 · 1 payment
Receiving payments does not imply wrongdoing. What Open Payments covers ·original records
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