John Grehan, MD PHD
NPI 1275549784 · Thoracic Surgery (Cardiothoracic Vascular Surgery) Physician · Sioux Falls, SD
Enrolled with Medicare as Practitioner - Cardiac Surgery · source: CMS PECOS Public Provider Enrollment (2026.04.01)
John Grehan, MD PHD is a Thoracic Surgery (Cardiothoracic Vascular Surgery) Physician provider in Sioux Falls, SD (NPI 1275549784).
Provider details
- NPI number
- 1275549784
- Entity type
- Individual
- Primary specialty
- Thoracic Surgery (Cardiothoracic Vascular Surgery) PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD PHD
- Sex
- Male
- Sole proprietor
- No
- License
- 35.088377 (OH)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure25% of score
19 yrs in NPPES registry
- Profile completeness25% of score
100% of core fields populated
- Practice footprint15% of score
2 documented practice locations
- Medicare service volume (vs. specialty peers)25% of score
258 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) |
|---|---|---|
| Replacement of Aortic Valve Through the Skin and Femoral Artery33361 | 74 | $662 |
| Initial Hospital Care With Moderate Level of Medical Decision Making, If Using Time, at Least 75 Minutes99223 | 29 | $161 |
| New Patient Office Or Other Outpatient Visit With a High Level of Medical Decision Making, If Using Time, 60 Minutes Or More99205 | 27 | $171 |
| Harvest of Vein Using an Endoscope33508 | 26 | $14 |
| Coronary Artery Bypass Using Artery Graft, 1 Graft33533 | 26 | $1,421 |
| Exclusion of Appendage of Left Upper Chamber of Heart Performed During Other Procedure on Chest33268 | 19 |
Transparency — industry payments
Based on CMS Open Payments, 2024; not all care is captured.
$46,073 across 32 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
Additional practice locations (1)
- 225 N Smith Ave#100aSt Paul, MN 55102Phone: (651) 241-7176Fax: (651) 241-5100
Registry dates
- Enumerated
- 2006-08-01
- Last updated
- 2022-04-09
- Certified
- 2022-04-09
Frequently asked questions
- What is John Grehan's NPI number?
- John Grehan's National Provider Identifier (NPI) is 1275549784, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is John Grehan's specialty?
- John Grehan is listed in the NPPES registry with a primary specialty of Thoracic Surgery (Cardiothoracic Vascular Surgery) Physician (Allopathic & Osteopathic Physicians).
- Where is John Grehan located?
- John Grehan's practice location on file with NPPES is 1301 W 18th St, Sioux Falls, SD 57105-0401.
- What is John Grehan's phone number?
- The practice phone number listed in the NPPES registry for John Grehan is (605) 312-2100.
- Does John Grehan accept Medicare?
- John Grehan is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is John Grehan's NPI active?
- Yes — John Grehan's NPI (1275549784) is active in the NPPES registry as of the last update on 2022-04-09.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.