Physician Profile
Unclaimed ProfileAbout GREHAN
John F Grehan, MD PHD practises thoracic surgery in Sioux Falls, SD. John is a 1995 graduate of University of Minnesota Medical School. John is also listed as specialising in thoracic surgery (cardiothoracic).
Summarised automatically from public NPI registry and CMS Medicare data. Not written or reviewed by this provider. Claim this profile to replace it.
Education & Training
Areas of Expertise
Common questions
What does Dr. Grehan specialise in?
Dr. Grehan is a thoracic surgeon in Sioux Falls, SD. This is the primary taxonomy recorded against the NPI in the federal registry, listed there as “THORACIC SURGERY”.
NPI registry
Where is Dr. Grehan located?
Dr. Grehan is listed at 1301 W 18TH ST, Sioux Falls, SD 57105. Addresses come from the NPI registry and can lag a move, so confirm before travelling.
NPI registry
What is Dr. Grehan's phone number?
The number on file is (605) 312-2100. Guide.md cannot book appointments or pass on messages — please call the office directly.
NPI registry
What is Dr. Grehan's NPI number?
Dr. Grehan's National Provider Identifier is 1275549784. It is issued by the Centers for Medicare & Medicaid Services and is unique and permanent — it does not change if they move practice.
NPI registry
Where did Dr. Grehan go to medical school?
Dr. Grehan attended University of Minnesota Medical School, graduating in 1995. This comes from the CMS National Downloadable File.
CMS public data
How long has Dr. Grehan been practising?
Dr. Grehan has 31 years experience. Calculated from a graduation year of 1995, reported in the CMS National Downloadable File.
CMS public data
What does Dr. Grehan do most often?
According to Medicare billing data, Dr. Grehan performs procedures including replacement of aortic valve through the skin and femoral artery, coronary artery bypass using artery graft, 1 graft and harvest of vein using an endoscope, alongside routine visits and testing. This reflects Medicare patients only and is billing volume, not a measure of quality.
Medicare claims
Has Dr. Grehan confirmed this information?
Not yet. This profile is built from public federal data and has not been confirmed by Dr. Grehan. If this is you, claiming it is free.
Guide.md
Licensing & Certification
Source: NPPES NPI Registry
Contact Information
- (605) 312-2100
- Email not available
Practice Locations
1301 W 18TH ST
Sioux Falls, SD 57105
Procedures Most Often Billed to Medicare
258 services · 258 patients · 10 distinct codes
| Procedure | Type | Code | Services |
|---|---|---|---|
| Replacement of aortic valve through the skin and femoral artery | Procedure | 33361 |
74 |
| Coronary artery bypass using artery graft, 1 graft | Procedure | 33533 |
26 |
| Harvest of vein using an endoscope | Procedure | 33508 |
26 |
| Exclusion of appendage of left upper chamber of heart performed during other procedure on chest | Procedure | 33268 |
19 |
| Coronary artery bypass using vein or artery graft, 2 grafts | Procedure | 33518 |
15 |
| Initial hospital care with moderate level of medical decision making, if using time, at least 75 minutes | Office visit | 99223 |
29 |
| New patient office or other outpatient visit with a high level of medical decision making, if using time, 60 minutes or more | Office visit | 99205 |
27 |
| Initial hospital care with straightforward or low-level medical decision making, if using time, at least 55 minutes | Office visit | 99222 |
16 |
| New patient office or other outpatient visit with moderate level of medical decision making, if using time, 45 minutes or more | Office visit | 99204 |
13 |
| New patient office or other outpatient visit with moderate level of medical decision making, if using time, 45 minutes or more | Office visit | 99204 |
13 |
Source: CMS Medicare public data. Shows how often procedures were billed — not quality of care or patient satisfaction.
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Connections drawn from the registry and from what providers have told us. A link here is not a referral or an endorsement.
Other thoracic surgeons at this location 1
Same specialty, same street address — most likely the same department or group.
Related specialists at this location 4
Clinically related specialties at the same address — the people this provider most likely works alongside.
Also at this address 4
Providers at the same street address. Each files their own registry entry, so a shared practice often appears under several different names.
More connections — 23 related providers in 4 groups
Other thoracic surgeons in Sioux Falls 2
Same specialty, same city.
Trained at University of Minnesota Medical School 7
Other providers in the same specialty who trained at the same institution.
Class of 1995 at University of Minnesota Medical School 8
Providers who graduated from the same medical school in the same year.
Also performs Replacement of aortic valve through the skin and femoral artery 6
Providers in SD who bill this service to Medicare most often.
Provider data sourced from the NPPES NPI Registry and CMS public datasets. Information is provided for reference and is not medical advice.