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Frequently Asked Questions
The trial design for RECHARGE is based on the premise that what matters most to patients is how long they live and how well they live. The win ratio gives the highest priority to how long patients live (survival time), and among survivors considers their quality of life.
Specifically, the win ratio method compares every patient in the CABG group to every patient in the PCI group. For each pairwise comparison, the patient who survives the longest is designated the winner. If neither patient dies, then the patient who had the most favorable change in quality of life after revascularization wins. When every patient in the CABG group has been compared to every patient in the PCI group, the number of wins for each group will be summed up. The ratio between the wins in the CABG group and the wins in the PCI group is the win ratio.
An important advantage of the win ratio is that it allows us to include both survival time and the time-averaged quality of life scores in a single composite endpoint, while prioritizing mortality as the more important component. The primary win ratio analysis will answer whether CABG can be expected to result in a more favorable outcome than PCI (or vice versa) in regards to mortality and average quality of life over 3-5 years.
The primary analysis will be supplemented by detailed analyses (using other methods) comparing differences in survival and quality of life over time after CABG versus PCI, which will further improve patients’ understanding of what to expect after each procedure. The frequent and detailed assessment of quality of life during the course of the trial will allow for uniquely detailed assessments of the relative impact of these procedures on short- and long-term quality of life.
In all prior studies, quality of life has been assessed at discrete time points, such as 30 days, 1 year, or 3 years. However, quality of life varies over time, especially after hospital procedures. RECHARGE thus believes it is important to assess quality of life over an extended period of time after both PCI and CABG to assess both the risks and benefits of each procedure. Therefore, we will be measuring "time-averaged" quality of life. This means that the quality of life measured in every 1-month increment will count equally. Specifically, over a 5-year period the the quality of life will be assessed in 60 individual monthly periods and averaged over that total time.
Patients treated for heart disease want to "live longer and live better", the latter reflected in quality of life measurements. We will be using standard quality of life questionnaires, for example the "Short Form 12 survey" and the "Seattle Angina Questionnaire" that have been proven to be reproducible and strongly associated with survival and other prognostic outcomes.
Different physicians and indeed different healthcare systems have varying opinions as to the suitability of PCI and CABG for specific individual patients. RECHARGE is a large scale randomized clinical trial program that will enroll approximately 1200 patients from approximately 60 sites, both urban and rural, teaching and community-based, etc., that will reflect the real-world practice of revascularization in the US. At each site, a heart team consisting of a general cardiologist, interventional cardiologist, and cardiac surgeon will have to agree that there is equipoise that revascularization by both PCI and CABG can be safe and effective for each patient considered for randomization in RECHARGE.
Standard MACE outcomes will be assessed and adjudicated in RECHARGE. However, there is no agreement as to how to best define some of these events, such as peri-procedural myocardial infarction. In addition, not all events are equivalent: for example, nearly everyone would agree that strokes are more important that repeat revascularizations, but they are both counted equally in standard time to first event MACE outcomes. And even among the category of stroke, some are devastating while others are minor or even resolve completely within a few days - yet they are all counted equally. Finally, many outcomes that are prognostically important that may be affected by PCI and CABG are not counted in the classic MACE outcome, such as major bleeding, severe arrhythmias requiring treatment, vascular complications, rehospitalizations, acute and chronic kidney disease, cognitive decline, etc. The clinical impact (and duration) of all non-fatal outcomes will be reflected in the generic quality of life outcome. However, RECHARGE will collect, adjudicate and report more than 25 adverse events (MACE and beyond) so patients and physicians can appreciate the full range of outcomes after PCI and CABG.
More Detail on the Use of Win Ratio in RECHARGE
The primary endpoint in both RECHARGE: Women and RECHARGE: Minorities will be evaluated using the unmatched win ratio (WR) method and the Joint Rank Test proposed by Finkelstein and Schoenfeld (FS). Specifically, the primary efficacy endpoint is a hierarchical composite of the following outcomes through all available follow-up in descending order of priority:
- All-cause death
- Change from baseline in the physical SF-12v2 summary score*
- Change from baseline in the mental SF-12v2 summary score*
*To determine the time-averaged QOL, the change in QOL from baseline to each interval will be multiplied by a factor representing the number of months of QOL that the interval represents, summed and divided by the total number of months.
General principle behind the win ratio. | |
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Comparison of each potential patient pair (e.g., 1 from CABG group and 1 from PCI group) over the course of their common follow-up time |
Assessment |
Step 1. If one or both patients die: |
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CABG wins |
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PCI wins |
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Go to step 2 |
If neither of the patients die | Go to step 2 |
Step 2. If no ranking yet available: |
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CABG wins |
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PCI wins |
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Go to step 3 |
Step 3. If no ranking yet available: |
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CABG wins |
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PCI wins |
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Tie |
When every patient in the CABG group has been compared to every patient in the PCI group, the number of wins for each group will be summed up. The ratio between the wins in the CABG group and the wins in the PCI group is the win ratio.
References:
Finkelstein DM, Schoenfeld DA. Combining mortality and longitudinal measures in clinical trials. Stat Med. 1999 Jun 15;18(11):1341-54.
https://doi.org/10.1002/(SICI)1097-0258(19990615)18:11%3C1341::AID-SIM129%3E3.0.CO;2-7.
Pocock SJ, Ariti CA, Collier TJ, Wang D. The win ratio: a new approach to the analysis of composite endpoints in clinical trials based on clinical priorities. Eur Heart J. 2012 Jan;33(2):176-82.
https://doi.org/10.1093/eurheartj/ehr352 .