DR. MICHAEL PETER KOUMJIAN MD
NPI 1366403321
Thoracic Surgery (Cardiothoracic Vascular Surgery) in La Mesa, CA
About Dr. Michael Peter Koumjian Md NPPES
Official registry information on file with the National Plan and Provider Enumeration System.
DR. MICHAEL PETER KOUMJIAN MD (NPI 1366403321) is an individual thoracic surgery (cardiothoracic vascular surgery) provider in La Mesa, California, licensed in California (G37886) and active in the NPI registry since March 2006. He is enrolled in Medicare PECOS and is a graduate of Rutgers New Jersey Medical School (1977).
NPPES Registry Identity
Specialties & Licenses
Other Identifiers 1
Medicare Participation & PECOS CMS
Medicare enrollment, assignment, billing reassignment, and ordering and referring status from CMS.
Medicare Enrollment Status
Enrolled in Medicare and accepts Medicare assignment
Dr. Michael Peter Koumjian Md is registered in PECOS and agrees to accept the Medicare-approved amount as full payment. Medicare patients are not billed beyond the standard deductible and coinsurance.
Medicare Billing Reassignments
5Medicare enrollment records show Michael Koumjian reassigns Medicare billing to 5 organizations. Each organization bills Medicare for the services this provider delivers there; the nearest is listed first.
La Mesa, CA 91942
- Reassigned Medicare billing, California enrollment
San Diego, CA 92123
- Reassigned Medicare billing, California enrollment
- 1,437 clinicians in this Medicare group
San Diego, CA 92103
- Reassigned Medicare billing, California enrollment
- 1,598 clinicians in this Medicare group
San Diego, CA 92103
- Reassigned Medicare billing, California enrollment
- 218 clinicians in this Medicare group
Tulare, CA 93274
- Reassigned Medicare billing, California enrollment
- Also billed through NPI 1790795458 (California)
- 184 clinicians in this Medicare group
Source: CMS Revalidation Reassignment List, October 2026 release. Reassignment records can lag staffing changes; confirm a current affiliation with the organization.
Areas of Expertise CMS Part B claims 12
Services this provider delivered to Medicare fee-for-service patients, from the CMS Medicare utilization data. Higher counts generally reflect more experience with a service; care delivered outside Medicare is not included.
Physician Visit Costs CMS claims · ZIP area
Typical Medicare office-visit costs in the 91942 ZIP code area, from fee-for-service claims. These are area statistics, not this provider’s prices; actual charges vary by service and coverage.
Other Providers at the Same Location NPPES 20
Providers registered at the same practice address, or within the immediate area, according to the NPPES registry.
LA MESA, CA 91942
Frequently Asked Questions NPPES & CMS
Common questions about this NPI record, answered from the official NPPES registry and CMS datasets shown on this page.
What is Michael Koumjian's NPI number?
The NPI number for Michael Koumjian is 1366403321. It was assigned to this individual provider in the NPPES registry on March 30, 2006.
Where is Michael Koumjian located?
Michael Koumjian practices at 5525 Grossmont Center Dr Ste 609, La Mesa, CA 91942. The listed phone number is (619) 466-5700.
What is Michael Koumjian's specialty?
The primary specialty registered for this NPI is Thoracic Surgery (Cardiothoracic Vascular Surgery) with taxonomy code 208G00000X.
Is Michael Koumjian enrolled in Medicare?
Yes. Michael Koumjian is registered in the Medicare PECOS system and accepts Medicare assignment, which means accepting the Medicare-approved amount as payment in full for covered services.
Which organizations bill Medicare for Michael Koumjian's services?
According to the CMS Revalidation Reassignment List (October 2026 release), Michael Koumjian reassigns Medicare benefits to 5 organizations: Michael P. Koumjian, MD, A Professional Corporation (La Mesa, CA), Emergency And Acute Care Medical Corporation (San Diego, CA), Scripps Health (San Diego, CA), On Call Specialists Medical Group Of San Diego, Inc. (San Diego, CA) and Kaweah Delta Health Care District (Tulare, CA). Each reassignment is filed with Medicare on form CMS-855R, signed by both the clinician and the organization, and lets the organization bill Medicare and receive payment for Michael Koumjian's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.
When was this NPI record last updated?
The NPPES record for Michael Koumjian was last updated on February 2, 2018. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 8 years ago. If this record has changed at CMS more recently, you can request an on-demand re-check against the live CMS registry, directly from this page.
# Dr. Michael Peter Koumjian, MD · NPI 1366403321
Thoracic Surgery (Cardiothoracic Vascular Surgery) physician in La Mesa, California. Individual provider, active in the CMS NPPES registry since March 30, 2006.
## Identity
- **NPI:** 1366403321 (Entity type: Individual)
- **Enumerated:** March 30, 2006
- **Primary specialty:** Thoracic Surgery (Cardiothoracic Vascular Surgery) · taxonomy 208G00000X
- **State license:** G37886 (California)
- **Sole proprietor:** Yes
## Practice location
- **Address:** 5525 GROSSMONT CENTER DR, STE 609, La Mesa, CA 91942
- **Phone:** (619) 466-5700 · **Fax:** (619) 460-8975
## Medicare
- **Medicare:** Enrolled (PECOS); accepts Medicare assignment
- **Ordering & referring:** eligible for Part B labs & imaging, durable medical equipment, home health, power mobility devices
- **Bills Medicare through:** 5 organizations under Medicare reassignment (form CMS-855R): Michael P. Koumjian, MD, A Professional Corporation (NPI 1528276078, La Mesa, CA); Emergency And Acute Care Medical Corporation (NPI 1437103942, San Diego, CA); Scripps Health (NPI 1881636108, San Diego, CA); On Call Specialists Medical Group Of San Diego, Inc. (NPI 1962175836, San Diego, CA); Kaweah Delta Health Care District (NPI 1679270581, Tulare, CA) · CMS Revalidation Reassignment List, October 2026 release
- **Medical school:** Rutgers New Jersey Medical School, class of 1977
## Record status
- **NPPES last updated:** February 2, 2018
- **Other identifiers:** Medicaid GR0066270 (CA)
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Source: [NPI Profile](https://npiprofile.com/npi/1366403321) · Data from the CMS NPPES public registry.