Michael Koumjian, MD
NPI 1366403321 · Thoracic Surgery (Cardiothoracic Vascular Surgery) Physician · La Mesa, CA
Enrolled with Medicare as Practitioner - Cardiac Surgery · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Michael Koumjian, MD is a Thoracic Surgery (Cardiothoracic Vascular Surgery) Physician provider in La Mesa, CA (NPI 1366403321).
Provider details
- NPI number
- 1366403321
- Entity type
- Individual
- Primary specialty
- Thoracic Surgery (Cardiothoracic Vascular Surgery) PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Male
- Sole proprietor
- Yes
- License
- G37886 (CA)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure25% of score
20 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
891 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) |
|---|---|---|
| Subsequent Hospital Care With Moderate Levelof Medical Decision Making, If Using Time, at Least 35 Minutes99232 | 266 | $79 |
| X-Ray of Chest, 1 View71045 | 207 | $8 |
| Subsequent Hospital Care With Moderate Levelof Medical Decision Making, If Using Time, at Least 50 Minutes99233 | 132 | $119 |
| Initial Hospital Care With Moderate Level of Medical Decision Making, If Using Time, at Least 75 Minutes99223 | 117 | $173 |
| Ultrasound of Heart, Follow-Up93308 | 39 | $25 |
| Insertion of Tube in Left Heart Chambers for Diagnosis With Review By Radiologist93452 | 26 |
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 2 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Enoxaparin Sodium | 15 | 12 |
| Oxycodone Hcl/Acetaminophenbrand: Oxycodone-Acetaminophen | 13 | — |
Medicare Part D only. These counts cover prescriptions paid through Medicare Part D in 2024 — they do notinclude cash-pay, commercial-insurance, Medicaid, or Part B–administered drugs, and badly undercount high cash-pay categories (e.g. GLP-1 weight-loss, testosterone, and ED medications). Any drug with 10 or fewer claims is omitted by CMS, and beneficiary counts under 11 are suppressed — so a missing drug means no Part D record, never zero. This is a factual claims summary, not an endorsement, not medical advice, and not a consumer report. Source: CMS Medicare Part D Prescribers — by Provider and Drug.
Transparency — industry payments
Based on CMS Open Payments, 2024; not all care is captured.
$3,230 across 46 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
- 2006-03-30
- Last updated
- 2018-02-02
Frequently asked questions
- What is Michael Koumjian's NPI number?
- Michael Koumjian's National Provider Identifier (NPI) is 1366403321, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Michael Koumjian's specialty?
- Michael Koumjian is listed in the NPPES registry with a primary specialty of Thoracic Surgery (Cardiothoracic Vascular Surgery) Physician (Allopathic & Osteopathic Physicians).
- Where is Michael Koumjian located?
- Michael Koumjian's practice location on file with NPPES is 5525 Grossmont Center Dr, La Mesa, CA 91942.
- What is Michael Koumjian's phone number?
- The practice phone number listed in the NPPES registry for Michael Koumjian is (619) 466-5700.
- Does Michael Koumjian accept Medicare?
- Michael Koumjian is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Michael Koumjian's NPI active?
- Yes — Michael Koumjian's NPI (1366403321) is active in the NPPES registry as of the last update on 2018-02-02.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.