for people ages 65 years and up (full criteria)
at San Francisco, California and other locations
study started
estimated completion
Principal Investigator
by Tom Nguyen, MD
Headshot of Tom Nguyen
Tom Nguyen



This is a prospective, multicenter, open-label, randomized trial comparing mitral valve (MV) transcatheter edge-to-edge repair (TEER) to surgical repair (1:1 ratio) in patients with primary, degenerative mitral regurgitation (MR). The trial will be conducted in the U.S., Canada, Germany and the United Kingdom, and is designed as a strategy trial. Thus, all devices legally marketed for TEER of primary degenerative MR in a particular country are eligible to be used in this trial.

Official Title

Percutaneous or Surgical Repair In Mitral Prolapse And Regurgitation for ≥65 Year-olds (PRIMARY)


The primary aim of this study is to evaluate the long-term effectiveness and safety of MV TEER compared with surgical repair in patients with primary, degenerative MR. The secondary aim is to analyze the relationship between the adequacy of MR correction at one-year post randomization and longer-term clinical outcomes (death, heart failure hospitalizations/urgent care visits, valve re-interventions, and quality of life). The tertiary aim of this trial is to evaluate a range of patient-centered outcomes (quality of life, functional status, and discharge location) of transcatheter edge-to-edge MV repair compared with MV surgical repair in patients with primary, degenerative mitral regurgitation. The patient population for this trial consists of adult patients with severe, primary degenerative MR for whom the local heart team has verified that an indication for MV intervention is present and for whom both transcatheter edge-to-edge and surgical repair strategies are anatomically feasible. Because the use of the commercial edge-to-edge mitral repair device in the U.S. is approved only in patients considered to be at prohibitive risk of MV surgery by a heart team, use of such devices in this trial is considered investigational by the FDA. As such, this trial will be conducted under an Investigational Device Exemption (IDE ). All patients with qualifying MR, who decline randomization, will be offered the option of enrollment in a parallel registry that captures their baseline risk profile and their treatment strategy received. These patients will also be asked to fill out a brief decliner survey. Outcomes will be measured over a period of 5 years. The estimated enrollment period is 36 months, and all patients will be followed for up to 10 years post randomization for particular endpoints. Long-term follow-up will include leveraging administrative datasets linked to clinical trial data.


Mitral Valve Regurgitation, surgical mitral valve repair, transcatheter edge-to-edge repair, Mitral Valve Insufficiency, Mitral valve repair


For people ages 65 years and up

The patient population for this trial consists of adults with severe, primary degenerative MR for whom the local heart team has verified that an indication for MV intervention is present and for whom both transcatheter edge-to-edge and surgical repair strategies are anatomically feasible. Specific inclusion and exclusion criteria are listed below. All patients who meet eligibility criteria will be included in the study regardless of gender, race, or ethnicity.

Inclusion Criteria:

  • Adult patients ≥65 yrs with moderately-severe or severe (3+ or 4+/4+) primary degenerative (Carpentier type II) MR defined by transthoracic echocardiography
  • Clinical indication for MV intervention and anatomic candidate for both MV transcatheter edge-to-edge and surgical repair per local heart team assessment
  • Patients across the surgical risk spectrum (low, intermediate, and high risk) depending on the local heart team assessment (see 2020 ACC/AHA guidelines for the management of patients with valvular heart disease)
  • Patients with AF who meet an indication for concomitant ablation may be included provided the local heart team verifies they are eligible for both catheter-based and surgical ablation.
  • Ability to perform 6-minute walk test (6MWT) and complete Kansas City Cardiomyopathy Questionnaire (KCCQ) instrument

Exclusion Criteria:

  • Other forms of primary MR (e.g., cleft leaflet, endocarditis)
  • Secondary or functional MR
  • Hypertrophic obstructive cardiomyopathy
  • Presence of an IVC filter or pacing/ICD leads that would interfere with TEER per local heart team assessment
  • Known allergic reactions to intravenous contrast
  • Febrile illness within 30-days prior to randomization
  • Any absolute contraindication to transesophageal echocardiography
  • Any contraindication to systemic heparinization including active bleeding diatheses, and heparin induced thrombocytopenia
  • Any prior MV intervention or any prior repair of atrial septal defect
  • Need for any of the following concomitant procedures: aortic valve or aortic surgery, tricuspid valve surgery
  • Patients with CAD requiring revascularization
  • Need for any emergency intervention or surgery
  • Active endocarditis
  • Hemodynamic instability defined as cardiac index <2.0 l/min/m2 or systolic blood pressure <90mmHg or need for inotropic support or any mechanical circulatory support
  • Left ventricular ejection fraction <25%
  • Intracardiac mass or thrombus
  • Co-morbid medical or oncologic condition for which local heart team believes that meaningful survival beyond 2 years is unlikely
  • Current substance abuse disorder
  • Suspected inability to adhere to follow-up
  • Treatment with another investigational drug or other intervention, assessment of which has not completed its primary endpoint or that clinically interferes with the present study endpoints.


  • University of California San Francisco accepting new patients
    San Francisco California 94143 United States
  • Stanford University not yet accepting patients
    Stanford California 94305 United States

Lead Scientist at UCSF

  • Tom Nguyen, MD
    Professor, Surgery, School of Medicine. Authored (or co-authored) 178 research publications


accepting new patients
Start Date
Completion Date
Annetine Gelijns
Study Type
Expecting 450 study participants
Last Updated