Skip to content

Write for patients
Blog
Plans

Search providers

Log in
Claim my profile

Find a Doctor

Search providers State

Filters

Cardiovascular Diseaseremove filter
WYremove filter
Douglasremove filter

ZIP code

Enter 3 digits for a wider area, 5 for an exact code.

Individuals or organizations

Individual providers
Organizations & facilities

Provider type

Physicians & surgeons (MD, DO)
Nurse practitioners & PAs
Mental & behavioral health
Therapists, pharmacists & allied health

Gender

Female
Male

Availability & listings

Accepting new patients
Telehealth
Treats on lien
Expert witness
Appointment requests
Industry consultant

Specialty clear

Nothing matches that.

Years of experienceTaken from the provider's graduation year where CMS publishes it, otherwise from how long they have held an NPI — which is a minimum, since NPIs only began in 2005.

Under 5 years
5 to 15 years
15 to 25 years
Over 25 years

State clear

Nothing matches that.

City clear

Nothing matches that.

1 providers

SortVerified firstMost experience Name A–Z

Verified profiles first, then the most complete. How this ordering works · Complete yours

Allan L. Mattern, M.D.M.D.

Unclaimed · claim it

Cardiovascular Disease

Douglas, WY
19+ years experience
(307) 358-7300
NPI 1023175635

View Profile Claim

We believe every healthcare provider should hold the keys to their online identity — including how search and AI describe their practice, what they treat, what they do, and how they want their work represented.

Directory

Find a doctor
Practices
Specialties
Locations
Conditions
Procedures & services
Accepting new patients
Telehealth providers
Doctors on lien
Expert witnesses
Industry consultants

For providers

Claim your profile
Why it matters
Your specialty, in one minute
Why claim your profile
Write for patients
Articles by providers
Show up in AI search
Who reads Guide.md
How it works
Plans & pricing
Free visibility check
Before you hire an agency
Your online presence
AI visibility, explained
Visibility by specialty
Compare
For agencies
Referral program

How this works

How we rate
Data sources
Verification standards
Search & featured listings
Editorial policy
Reclaim your profile

Company

About
Blog
Contact
Accessibility

Legal

Privacy Policy
Terms of Use
AI & medical disclaimer

Healthcare provider and practice information is compiled from multiple public and other data sources, including the NPI Registry. Guide.md helps providers and practices manage their professional identity, verify their information, improve how they are represented online, and participate in optional appointment, consulting, lien-care, and other professional listings. Information is provided for reference only and is not medical advice. Profiles, verification badges, ratings, featured placement, professional listings, or other Guide.md services do not constitute a medical endorsement or guarantee of a provider’s services.

© 2026 GigHz LLC. All rights reserved.

Tell us

Fix a provider profile

Provider or practice name NPI

The NPI is on the profile, under the name. Say in the box what should change.

Take a profile off the site

Suppression is handled by a person. Open the suppression form; it asks who you are and which profile, and we confirm by email.

Something on this page is broken Something else

Needed so we can write back about the change. No newsletters.

Thank you. We read every one of these.

A GigHz company · Founder: Pouyan Golshani, MD