Ioannis Mastoris, MD
Internal Medicine, Advanced Heart Failure and Transplant Cardiology (MD) with Massachusetts General Physicians Organization Inc, practicing in Boston, Massachusetts. Their prescriptions cost Medicare Part D more than their services did: $885,257 for 1,007 claims, against $117,835 paid for services in 2024. Endotronix, Inc. was the largest of 3 companies reporting payments in 2025, $480.91 in all, mostly food and beverage. Lists Brigham and Women's Hospital and 4 other hospitals as hospital affiliations.
Overview
| NPI | 1124403209 |
|---|---|
| Status | Active |
| Entity type | Individual |
| Credential | MD |
| Sole proprietor | No |
| NPI issued | Jul 30, 2015 |
| Last updated in NPPES | May 1, 2023 |
| Certified by provider | May 1, 2023 |
Specialties and licenses
Exclusion screening
| List | Result | Details |
|---|---|---|
| HHS-OIG LEIE · Oct 9, 2026 | No match | Checked by NPI and by name + state |
| North Carolina Medicaid · Nov 10, 2026 | No match | — |
| New York OMIG · Nov 10, 2026 | No match | — |
| Ohio Medicaid · Nov 10, 2026 | No match | — |
| Pennsylvania Medicheck · Nov 10, 2026 | No match | — |
| Washington HCA · Nov 10, 2026 | No match | — |
Official OIG search · How matching works ·Bulk check a roster
Medicare
| Enrollment (PECOS) | Enrolled Practitioner - Advanced Heart Failure and Transplant Cardiology (MA); Practitioner - Advanced Heart Failure and Transplant Cardiology (NH) |
|---|---|
| Accepts assignment | Yes (participating) |
Medicare services in 2024
| Medicare patients | 276 |
|---|---|
| Services billed | 1,298 across 23 procedure codes |
| Paid by Medicare | $117,835 |
Part D prescriptions in 2024
| Prescriptions (claims) | 1,007 · 2,399 30-day fills |
|---|---|
| Patients | 150 |
| Total drug cost | $885,257 |
| Generic share | 61% of claims |
Education and affiliations
| Graduation year | 2011 |
|---|---|
| Medicare specialty | Advanced Heart Failure And Transplant Cardiology |
| Secondary specialties | Cardiovascular Disease (Cardiology) |
| Telehealth | Offers telehealth |
Medical group
- Massachusetts General Physicians Organization IncBoston, MA · 3,558 clinicians
Hospital affiliations
- Brigham and Women's HospitalBoston, MA
- Cooley Dickinson Hospital Inc,theNorthampton, MA
- Massachusetts General HospitalBoston, MA
- Newton-Wellesley HospitalNewton, MA
- North Shore Medical Center -Salem, MA
Industry payments (Open Payments)
- 2025$480.91 · 3 payments from 3 companies
- 2024$578.85 · 5 payments from 2 companies
Top paying companies in 2025
| Company | Amount | Payments |
|---|---|---|
| Endotronix, Inc. | $294.18 | 1 |
| Impulse Dynamics (USA) Inc. | $158.82 | 1 |
| Abbott Laboratories | $27.91 | 1 |
What the 2025 payments were for
- Food and Beverage$480.91 · 3 payments
Receiving payments does not imply wrongdoing. What Open Payments covers ·original records
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