Seestrasse 455b,
CH – 8038 Zurich
Monday to Friday
9:00 AM – 5:00 PM
info@angioclinic.ch
+41 44 482 30 30
ENDE

Our Team in Zurich – Vein Specialists & Doctors

The Team in Zurich

Dr. Johann C. Ragg, MD | Chief Physician more Info

I studied physics before becoming a doctor. Since 1981, I have been working on the development of lasers and their applications. My specialty is radiology, where I have focused on imaging techniques such as ultrasound and minimally invasive treatments. Having performed more than 250,000 ultrasound examinations of blood vessels, I am able to make highly accurate diagnoses. At the same time, I have a broad general medical background, allowing me to provide you with personalized advice.

Since 1990, I have focused exclusively on interventional vascular medicine. This involves using miniature instruments to treat veins and arteries without major surgery. I have performed more than 100,000 successful catheter procedures and therefore have particularly extensive experience and a foundation for developing new methods.

I developed the angioclinic® vein therapy in Switzerland. It is specifically tailored to the needs of the Swiss population and the Swiss insurance system. I have lived and worked in Switzerland since 2009, but I also treat patients in Munich and Berlin.

My memberships in medical associations, in addition to the Swiss Society of Phlebology (SGP) and the Union of Swiss Societies for Vascular Diseases (USGG), are currently being updated for you, as are my scientific activities.

Dr. Sebastian Kreis, MD | Attending Physician Zurich

As an FMH-certified general practitioner and specialist in general medicine (Germany), Dr. Sebastian Kreis has been supporting the angioclinic Venous Center Zurich for many years, particularly in the fields of aesthetic vein medicine, ultrasound diagnostics, and internal medicine and general medical differential diagnosis.

Having earned his doctorate in phlebology, Dr. Kreis has also been collaborating scientifically with Dr. Ragg for many years. Dr. Kreis is a member of the Swiss Society of Phlebology (SGP), the Union of Swiss Societies for Vascular Diseases (USGG), the German Society of Phlebology and Lymphology (DGPL), and the German Society for Ultrasound in Medicine (DEGUM), with certifications in the fields of peripheral vessels and internal medicine.

Dr. Kreis worked for five years at the smallest hospital in Switzerland, the Center da sandà Val Mustair (CSVM), and runs his own practice in Vitznau on Lake Lucerne. Dr. Kreis is an active fencer for Switzerland and also serves as a team and race physician in various sports disciplines.

Simon Grzelachowski | Phlebology Assistant

Simon Grzelachowski, whom most patients simply call “Mr. Simon,” has been working alongside Dr. Ragg for 18 years now. During this time, in addition to general venous medicine, he has gained in-depth knowledge of all the specialized phlebological procedures developed by Dr. Ragg and has been actively involved in all research projects.
Building on his initial training as a medical assistant, he completed advanced training in Germany to become a phlebology assistant (at the Training Academy of the German Society for Phlebology and Lymphology). In daily practice, he assists with the preparation and administration of medical and aesthetic therapies.
Thanks to his exceptional knowledge and skills, he supports our practices as a trainer for medical assistants and an ultrasound instructor for our physicians. In 2026, he was selected as the first partner candidate for the angioclinic® Vein Centers.

Birgit Marquardt | Member of the Management Board

Birgit Marquardt gained experience in dealing with people and managing finances at a major German bank when it was still headed by a well-known Swiss executive.
She is a founding member and co-owner of the angioclinic Group. Since 2010, she has been supporting our teams with organizational matters and personally addressing the specific concerns and requests of our patients.

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