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Cassius Iyad Ochoa Chaar, MD, MPH, MS, RPVI

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Associate Professor of Surgery (Vascular)



Associate Professor of Surgery (Vascular)


Cassius Iyad Ochoa Chaar, MD, MPH, MS, is an associate professor of surgery in the division of vascular surgery and endovascular therapy. He is seeing patients at the Yale Physicians Building. He is a board-certified in general surgery and vascular surgery, and is a registered vascular specialist in the interpretation of vascular laboratory studies. Dr. Chaar’s clinical interests include peripheral artery disease (PAD) focusing on patients with critical limb ischemia and limb salvage, varicose veins, aortic and visceral aneurysms, carotid disease, deep vein thrombosis, and dialysis vascular access. He completed his graduate and medical degrees at American University of Beirut, Lebanon. He spent his general surgery residency at Yale-New Haven Hospital, and subsequently finished a fellowship in vascular and endovascular surgery at University of Pittsburgh Medical Center.

As a recent graduate from the Yale School of Public Health (MPH 2023), Dr. Chaar has established extensive collaborations to study clinical genetics of vascular disease, explore applications of artificial intelligence to improve vascular care, and assess new technologies that enhance vascular surgery treatments. He mentors and trains MD/PhD students interested in surgical outcomes research, genetic research, and quality improvement related to surgical therapies.


    Other Departments & Organizations

    Education & Training

    Yale School of Public Health , Biostatistics (2023)
    University of Pittsburgh Medical Center (2011)
    Chief Resident
    Yale New Haven Hospital (2009)
    Yale New Haven Hospital (2008)
    Post-Doctoral research fellow
    Cleveland Clinic Foundation (2004)
    American University of Beirut (2002)
    American University of Beirut (2000)



    Research Projects for Students and Residents

    Project 1:

    Title: The significance of reinterventions in the treatment of peripheral artery disease (PAD)

    Description: Patients treated with open or endovascular revascularization of the lower extremities undergo frequently repeated intervention to sustain patency and to provide limb salvage in patients with critical limb ischemia. This project studies the impact and costs of reinterventions on patient outcomes.

    Project 2:

    Title: Prediction model for major amputation in patients with PAD

    Description: This patient will rely on large database data to identify factors that can predict major amputation in patients with PAD undergoing lower extremity revascularization.

    Project 3:

    Title: Characteristics and outcomes of patients with premature vascular disease

    Description: Vascular diseases such as peripheral arterial disease, abdominal aortic disease, and carotid disease are typically diseases of the elderly. Yet, some patients present at relatively young age and tend to have different characteristics and more aggressive forms of the disease. This project aims at better identifying the specific risk factors for those patients and better understand their outcomes after vascular surgery.

    Project 4:

    Title: Universal Algorithm for venous disease

    Description: Our understanding of venous disease and its treatment has evolved and there are several structural anomalies that can be surgically treated that can improve patient symptoms. However, there is no recommended and well defined protocol for the approach to the patient. This project studies the effect of the Yale Vascular Surgery protocol on the evaluation and outcomes of patients with venous disease affecting the lower extremities. The protocol was incorporated in a signature care pathway in epic (the electronic medical record). The project will study the impact of this integration on the care of patients with venous insufficiency at Yale New Haven Hospital.

    Project 5:

    Title: Iliofemoral DVT and post phlebetic syndrome in the DOAC era

    Description: This study aims to study the risk of postphlebetic syndrome after iliofemoral DVT in patients on DOAC compared to coumadin. Also, it will assess the incidence of postphlebetic syndrome after different types of DVT. This project is in collaboration with the hematology team.

    Project 6:

    Title: Management of vascular disease in the very old

    Description: As the population ages, vascular surgeons increasingly face complex patients in their 80s and 90s requiring treatment. This project aims to study the trends in treatment of vascular disease in the elderly, as well as the outcomes and focus on the impact on quality of life.

    Project 7:

    Title: Genetic predictors of revascularization outcomes

    Description: This project will use Yale data, UK biobank, and all of us data to identify genetic variants that can be associated with outcome of vascular revascularization. This project involves collaborators in the school of public health and the yale genetics department.

    Project 8:

    Title: Smoking cessation in vascular patients

    Description: Smoking is very prevalent in patients with vascular disease. Patients get advised about smoking cessation all the time. This study looks at different means to enhance cessation in vascular patients in the inpatient as well as the outpatient settings.

    Medical Subject Headings (MeSH)

    Aortic Aneurysm; Thrombolytic Therapy; Varicose Veins; Vascular Diseases; Vascular Surgical Procedures; Venous Thrombosis

    Research at a Glance

    Yale Co-Authors

    Frequent collaborators of Cassius Iyad Ochoa Chaar's published research.




    Clinical Trials

    Current Trials

    Academic Achievements and Community Involvement

    • honor

      John N Forrest, Jr Mentorship Award

    • honor

      Quality Improvement Grant

    • honor

      SVS Clinical Research Seed Grant

    • honor

      VSGNE Quality Improvement Grant

    • honor

      Juzzo Traveling fellowship

    Clinical Care


    Cassius Iyad Ochoa Chaar, MD, MPH, MS, is a vascular surgeon who treats problems affecting the circulatory system, ranging from painful varicose veins to life-threatening aneurysms. He has special expertise in treating peripheral artery disease, which can block blood flow through the arteries in the arms and legs. Dr. Chaar is an expert in lower extremity limb preservation, particularly in diabetic patients.

    “The most exciting breakthrough in vascular surgery has been the evolution of minimally invasive surgery, which has transformed the specialty completely,” Dr. Chaar says. Dr. Chaar says that he is now able to treat the vast majority of his patients with minimally invasive endovascular surgeries, which involve accessing a damaged artery by puncturing it and inserting a wire and a catheter. But he also still performs traditional open surgeries—with long incisions that allow him to view and treat problems directly. He sometimes uses a combination of approaches to treat complex cases.

    An associate professor of vascular surgery at Yale School of Medicine, Dr. Chaar says he was motivated to go into medicine when he was growing up and saw the positive impact a doctor had on his grandmother, who had complicated medical problems. “I wanted to be that person who touched peoples’ lives and made them better,” he says.

    Dr. Chaar is the 2020 recipient of the Charles W. Bohmfalk Prize for teaching in the clinical sciences at the Yale School of Medicine. He is also the 2023 recipient of the John N. Forrest, Jr Mentorship Award at the Yale School of Medicine.

    Dr. Chaar speaks Arabic, English, French and Spanish.

    Clinical Specialties

    Vascular & Endovascular Surgery

    Fact Sheets

    Board Certifications

    • Surgery Vascular

      Certification Organization
      AB of Surgery
      Latest Certification Date
      Original Certification Date
    • Surgery General

      Certification Organization
      AB of Surgery
      Latest Certification Date
      Original Certification Date

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