Nikolaos Zacharias, MD

Procedures

From CMS Care Compare, which counts the procedures a clinician billed to Original Medicare and Medicare Advantage over a recent 12-month period. CMS reports a fixed list of common procedures, so this is not everything the clinician does. Counts of 10 or fewer are given as a range, because CMS withholds small numbers.

The percentile compares how often this clinician performed the procedure with other clinicians who performed it, as CMS calculates it. It measures volume, not outcomes or skill.

Medicare patients and services, 2024

From the CMS Medicare Physician & Other Practitioners file for calendar year 2024. It counts Original Medicare patients only, so a practice that mostly sees Medicare Advantage or privately insured patients looks smaller here than it is.

Dollar amounts are not shown. What Medicare pays a practice is gross billings, before staff, premises and tax and including the cost of any drugs it administers, so it is not what a clinician earns.

Payments from drug and device companies, 2025

Drug and device makers are required by federal law (the Physician Payments Sunshine Act) to report what they pay or give to clinicians, and CMS publishes the reports as Open Payments. This is the 2025 program year. A report is a record of a payment, not an allegation of anything, and many are small items such as meals. Only general payments are listed here; research payments and ownership or investment interests are reported separately by CMS and are not shown.

Each amount is the sum of what companies reported for that kind of payment in 2025, rounded to the dollar. Not all of it is income to the clinician: a meal is not a fee, a charitable contribution goes to a charity, and a royalty or an acquisition payment is not a salary.

Check a report, or dispute one, at the source in CMS’s own tool, Open Payments. Corrections go through CMS’s dispute process. This site removes a home address on request and asks for no proof, because that is privacy; it will not remove an accurate payment report on request, because that is a statutory public disclosure.

Practises at

Facilities the CMS Facility Affiliation file lists for this clinician.

• Massachusetts General Hospital Hospital · Boston, MA
• Newton-Wellesley Hospital Hospital · Newton, MA
• Southern Nh Medical Center Hospital · Nashua, NH
• Mass General Brigham Home Care, Inc Home health agency · Newton, MA

Colleagues at Foundation Medical Partners Inc

Clinicians the CMS Doctors & Clinicians file lists under the same group practice. CMS counts 311 clinicians in the practice; 12 are shown here.

• Sarah Dean Physician Assistant · Nashua, NH
• Kim Ann Eldredge, NP Gerontology Nurse Practitioner · Concord, NH
• David Halter, DO Surgery Physician · Lafayette, IN
• Derek T Jurus, DO Obstetrics & Gynecology Physician · Nashua, NH
• Mrs. Kayleigh Rebecca Maas, PA-C Physician Assistant · Nashua, NH
• Kellie Anne Motschmann, MD Obstetrics & Gynecology Physician · Nashua, NH
• Anand Padmanabha, MD Orthopaedic Surgery Physician · Nashua, NH
• Troy Michael Robinson, PA-C Medical Physician Assistant · Keene, NH
• Ajay K Sharma, MD Cardiovascular Disease Physician · Nashua, NH
• MS. Jennifer Elise Shelsky X, APRN Family Nurse Practitioner · Amherst, NH
• Mrs. Katelyn Marie Tavares, APRN Family Nurse Practitioner · Milford, NH
• Dr. Gianfranco Tulliano, MD Internal Medicine Physician · Nashua, NH

Other providers in Lebanon

• Dr. Richard James Powell, MD

  Individual Vascular Surgery Physician · NPI 1942316914

  1 Medical Center Dr Section Of Vascular Surgery, Lebanon, NH 03756-1000 · (603) 650-8677

• Dr. David H Stone, MD

  Individual Vascular Surgery Physician · NPI 1083605117

  1 Medical Center Dr Dhmc Dept OF Surgery, Lebanon, NH 03756-1000 · (603) 650-4682

• Eric H Twerdahl Jr., MD

  Individual Vascular Surgery Physician · NPI 1093035461

  1 Medical Center Dr, Lebanon, NH 03756-0001 · (603) 650-5000

• Dr. Daniel Bernard Walsh, MD

  Individual Vascular Surgery Physician · NPI 1477564151

  1 Medical Center Dr, Lebanon, NH 03756-1000 · (603) 650-8191

• Dr. Robert Matthew Zwolak, MD

  Individual Vascular Surgery Physician · NPI 1487664629

  1 Medical Center Dr Dhmc Dept OF Surgery, Lebanon, NH 03756-1000 · (603) 650-8191