Koen Nieman, MD
NPI 1144778143 · Cardiovascular Disease Physician · Stanford, CA
Enrolled with Medicare as Practitioner - Cardiovascular Disease (cardiology) · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Koen Nieman, MD is a Cardiovascular Disease Physician provider in Stanford, CA (NPI 1144778143).
Provider details
- NPI number
- 1144778143
- Entity type
- Individual
- Primary specialty
- Cardiovascular Disease PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Male
- Sole proprietor
- No
- License
- 29048831401 (ZZ)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Other Service Providers
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure25% of score
9 yrs in NPPES registry
- Profile completeness25% of score
100% of core fields populated
- Practice footprint15% of score
1 documented practice location
- Medicare service volume (vs. specialty peers)25% of score
2,772 Medicare services, 2024 (ranked within specialty)
- Open Payments transparency10% of score
Has Open Payments disclosures (2024)
Medicare volume is ranked against active providers in the same specialty. Signals a provider has no public data for (e.g. Medicare claims) are left out of the score entirely — never counted as zero — so providers without that data are not penalized. See the full formula and weights in our .
What this provider does (Medicare)
Based on Medicare fee-for-service claims, 2024; not all care is captured.
| Service (HCPCS) | Medicare services | Typical Medicare-allowed (2024) |
|---|---|---|
| Ultrasound of Heart With Color-Depicted Blood Flow, Rate, Direction and Valve Function93306 | 812 | $77 |
| Routine Electrocardiogram (ecg) Using at Least 12 Leads With Interpretation and Report Only93010 | 669 | $9 |
| Ultrasound of Heart Blood Flow, Valves and Chambers, Follow-Up93321 | 213 | $8 |
| Ultrasound of Heart, Follow-Up93308 | 201 | $28 |
| Ultrasound of Heart With Color-Depicted Blood Flow, Rate, Direction and Valve Function93306 | 172 | $173 |
| Ultrasound of Heart With Color-Depicted Blood Flow, Rate and Valve Function |
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 8 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Atorvastatin Calcium | 48 | 16 |
| Metoprolol Succinate | 33 | — |
| Apixabanbrand: Eliquis | 19 | — |
| Carvedilol | 18 | — |
| Losartan Potassium | 16 | — |
| Metoprolol Tartrate | 13 | — |
| Ezetimibe | 12 |
Transparency — industry payments
Based on CMS Open Payments, 2024; not all care is captured.
$5,011 across 7 records (Open Payments 2024)
Open Payments discloses payments and transfers of value (meals, travel, consulting, research, royalties) from drug and device makers to providers. This is a transparency signal, not a verdict — such payments are legal and common, and their presence is neither an endorsement nor a criticism. Source: CMS Open Payments, program year 2024.
Practice location
Mailing address
Registry dates
- Enumerated
- 2016-09-19
- Last updated
- 2024-04-24
- Certified
- 2024-04-24
Frequently asked questions
- What is Koen Nieman's NPI number?
- Koen Nieman's National Provider Identifier (NPI) is 1144778143, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Koen Nieman's specialty?
- Koen Nieman is listed in the NPPES registry with a primary specialty of Cardiovascular Disease Physician (Allopathic & Osteopathic Physicians).
- Where is Koen Nieman located?
- Koen Nieman's practice location on file with NPPES is 300 Pasteur Dr, Stanford, CA 94305-2200.
- What is Koen Nieman's phone number?
- The practice phone number listed in the NPPES registry for Koen Nieman is (650) 723-4000.
- Does Koen Nieman accept Medicare?
- Koen Nieman is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Koen Nieman's NPI active?
- Yes — Koen Nieman's NPI (1144778143) is active in the NPPES registry as of the last update on 2024-04-24.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.