Early Percutaneous Mitral Intervention in Asymptomatic Moderate Mitral Stenosis (MITIGATE)
|Moderate Mitral Stenosis||Procedure: Percutaneous Mitral Commissurotomy||Phase 4|
|Study Design:||Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Open Label
Primary Purpose: Treatment
|Official Title:||Early Percutaneous Mitral Intervention Versus Conventional Management in Asymptomatic Moderate Mitral Stenosis|
- Composite of cardiovascular event [ Time Frame: Participants will be followed for the duration of the trial, a minimum follow-up of 3 years ]Composite of cardiovascular mortality, cerebral infarction, systemic embolic events that occurred during follow-up, and PMC-related complications; procedural mortality and urgent MV surgery.
- all-cause death and each component of cardiovascular event [ Time Frame: Participants will be followed for the duration of the trial, a minimum follow-up of 3 years ]all-cause death and any component of composite primary end point.
- Mitral valve replacement [ Time Frame: Participants will be followed for the duration of the trial, a minimum follow-up of 3 years ]
|Study Start Date:||July 2011|
|Estimated Study Completion Date:||December 2023|
|Estimated Primary Completion Date:||December 2018 (Final data collection date for primary outcome measure)|
Active Comparator: Early Percutaneous Mitral Intervention
early elective percutaneous mitral commissurotomy within 3 months of enrollment
Procedure: Percutaneous Mitral Commissurotomy
Percutaneous mitral commissurotomy is performed by experienced interventional cardiologists using the Inoue balloon technique. During the procedure, conventional hemodynamic parameters are monitored. A successful immediate result is defined as a mitral valve area > 1.5 square cm with less than moderate to severe mitral regurgitation.
Other Name: Percutaneous mitral valvuloplasty
No Intervention: Conventional Treatment
All patients in the conventional treatment group regularly visit their attending physicians at 3 monthly interval for maintenance of anticoagulation therapy or every year for annual re-evaluation. Patients who become symptomatic during follow-up are referred for percutaneous mitral commissurotomy or mitral valve surgery.
We enroll consecutive asymptomatic patients with moderate mitral stenosis who are candidates for both early percutaneous mitral commissurotomy (PMC) and conventional treatment at 3 centers in Seoul, Korea.
Echocardiographic evaluation is performed before enrollment, immediately after PMC and annually during follow-up. All patients undergo two-dimensional echocardiography and/or transesophageal echocardiography to detect left atrial thrombi. Morphologic features of the mitral valve (MV) are categorized as described previously (14), and total echocardiographic score is obtained by adding the scores for leaflet mobility, thickness, calcification, and subvalvular lesions. The MVA is measured by direct planimetry of the mitral orifice, and MS severity is graded as mild, moderate, or severe when MVA was > 1.5, 1.0 to 1.5, or < 1.0 cm2, respectively. The severity of mitral and tricuspid regurgitation is assessed semiquantitatively or using quantitative methods and classified as mild, moderate, or severe. Pulmonary artery systolic pressure (PAP) is estimated by continuous wave Doppler with the simplified Bernoulli equation.
All study patients regularly visit their attending physicians at 3 monthly interval for maintenance of anticoagulation therapy or every year for annual re-evaluation. Patients in the conventional treatment group who become symptomatic during follow-up are referred for PMC or mitral valve surgery. An embolic event is defined as a systemic embolism fulfilling both prespecified criteria: acute onset of clinical symptoms or signs of embolism and occurrence of new lesions confirmed by imaging studies. A specific diagnosis of cerebral infarction is confirmed by an experienced neurologist and additional brain magnetic resonance imaging is performed if indicated.
We estimate that a sample size of 166 patients would provide 80% power to detect a significant difference with respect to the primary end point at the 2-sided significance level of 0.05, assuming 3-year event rates of 13% in the conventional treatment group and 2% in the early PMC group, and drop-out rate of 5%. These rates are based on the results of our previous study. Analyses are performed on an intention-to-treat basis. To analyze primary outcome, estimates of cumulative event rates are calculated by the Kaplan-Meier method and compared employing the log-rank test. For Kaplan-Meier analysis, we analyze all clinical events by time to first event. Hazard ratios with 95% confidence intervals are derived with the use of the Cox proportional hazards model.
Please refer to this study by its ClinicalTrials.gov identifier: NCT01406353
|Korea, Republic of|
|Asan Medical Center|
|Seoul, Korea, Republic of, 138-736|
|Samsung Medical Center|
|Seoul, Korea, Republic of|
|Yonsei University Severance Hospital|
|Seoul, Korea, Republic of|
|Principal Investigator:||Duk-Hyun Kang, MD, PhD||Asan Medical Center|