Full CASCOM Study Summary


Carotid artery procedures (such as endarterectomy and stenting) are often performed even when patient benefit has not been established in past randomised trials.

Furthermore, there is no current evidence of procedural benefit compared to current optimal medical intervention alone for any person with carotid stenosis.

Medical intervention refers to lifestyle coaching and appropriate medication with respect to arterial disease risk factors, such as high blood pressure, blood cholesterol levels, physical inactivity, atrial fibrillation and tobacco smoking.

Medical intervention for stroke prevention is highly effective and continues to improve. The stroke prevention efficacy of current best medical intervention has not been measured.

In some places, the COVID-19 pandemic has made it difficult or impossible to perform carotid artery procedures. The pandemic has provided impetus to the CASCOM Study.


  1. To measure the rate of ipsilateral stroke, and other arterial disease complications, in individuals with advanced (50-99%) carotid stenosis who, for any reason, are managed using current best medical intervention alone.

    Reasons for a nonprocedural approach may include insufficient resources caused by the coronavirus pandemic, unproven procedural benefit, anticipated procedural futility and/or net harm, or patient refusal.

    We will study patients for whom carotid procedures are not possible or considered unethical and, therefore, where a randomised trial approach involving carotid procedures is inappropriate.

  2. To compare the CASCOM Study rate of ipsilateral stroke for symptomatic (stroke/transient ischaemic attack) patients with that in the North American Symptomatic Carotid Endarterectomy Trial (NASCET) and the European Carotid Surgery Trial (ECST), and the CASCOM Study rate of ipsilateral stroke associated with asymptomatic carotid stenosis with that in the Asymptomatic Carotid Atherosclerosis Study (ACAS).


CASCOM is a prospective study of current best medical intervention alone for stroke prevention in people who become patients by way of their referral for carotid imaging by a medical practitioner.

It is also a multi-national, multi-specialty, collaborative, quality assurance and evaluation project. We will separate patients into those who would, and would not, have been eligible for past randomised CEA trials.

We plan to study at least 367 symptomatic patients and at least 576 asymptomatic patients in the former, ‘eligible’, category and use these patients for hypothesis testing.

We expect at least a 50% lowering of stroke rates with medical intervention alone in the CASCOM Study compared to that seen in past randomised trials.

In addition, we plan to study 600 patients in the latter randomised trial ‘ineligible’ category.

We will report on rates of ipsilateral stroke and other complications over 5 years of follow-up. We will use ‘REDCap’ (Research Electronic Data Capture) for case reporting.

Findings and Significance

In the CASCOM Study we expect at least 50% lowering of the ipsilateral stroke rate compared to that seen with medical intervention alone in past randomised trials.

If correct, the CASCOM Study will provide new evidence that past randomised trials of CEA and CAS are outdated and elucidate new, improved standards for preventing stroke and other arterial disease complications.

Contact Information for the CASCOM Study

New CASCOM investigators and participants are welcome. If interested, please contact any of the CASCOM Chief Investigators (CI) or study coordinators (SC) as listed below:


Anne Abbott, PhD, MBBS, FRACP; CI, Melbourne

Tissa Wijeratne, MBBS MD FRACP FRCP(Edin) FRCP(London) FAAN; CI, Melbourne


Saeid H. Shahidi, MD; CI, Roskilde


Luca Saba, MD; CI, Cagliari

Pier Luigi Antignani, MD, PhD, FIUA; CI, Rome

United Kingdom

Alun Davies, MA, DM, FRCS, DSc, FHEA, FEBVS, FACPh, FLSW; CI, London

Ankur Thapar, PhD, FCRCS (Gen Surg), FHEA, PGCertMedEd; CI, London

Gregory Lip, MD FRCP; CI, Liverpool


Sherif Sultan, MD FRCS FACS PhD; CI, Galway


Christos Liapis, MD, PhD, FACS, FRCS Eng, FEBVS; CI Athens

Efthymios “Makis” Avgerinos, MD, FACS, FEBVS; CI Athens

United States of America

Hannah Gardener, ScD: CI, Miami


Claude Vaislic, MD, FEBTCVS; CI, Le chesnay


Grzegorz Madycki, M.D., Ph.D, FSPVS; CI, Warsaw

Piotr Myrcha, MD, PhD, FSVS; CI, Warsaw

Saudi Arabia

Omar Ayoub MBBS, FRCPC, CI, Jeddah


Hrvoje Budincevic, MD PhD, FEAN, FESO; CI, Zagreb