Effect of myocardial viability, percutaneous coronary intervention and functional recovery on clinical outcomes in the REVIVED-BCIS2 randomized trial
Reported from ACC/WCC 2023
Dejan Milasinovic provides his take on this clinical trial which was presented by Divaka Perera (London, United Kingdom), at the American College of Cardiology (ACC/WCC) 2023 Scientific Session.
Why this study? – the rationale/objective
This planned secondary study of the REVIVED-BCIS2 trial showed that performing viability testing to guide PCI in patients with heart failure (HF) and coronary artery disease (CAD) was not associated with improved outcomes.
How was it executed? – the methodology
Viability was assessed in two directions:
- as potential for recovery (normal vs. dysfunctional but viable vs. non-viable myocardium, n = 610),
- and as presence of scar tissue (n = 478).
What is the main result?
CMR was used in 78 % of the patients, and dobutamine stress echo in the rest. Whereas the presence of dysfunctional but viable myocardium was unrelated to clinical outcomes, the amount of scar burden did predict death and heart failure hospitalizations. Similarly, unlike dysfunctional but viable myocardium, the extent of scar tissue was associated with LV recovery at 6 months. Importantly, the overall neutral effect of PCI did not change respective to the presence of either scar tissue or dysfunctional but viable myocardium.
Critical reading and the relevance for clinical practice
These observations, although mainly hypothesis-generating, shed new light onto the complex interplay between coronary artery disease and heart failure.
First, the concept of hibernating myocardium may need to be reappraised, as both REVIVED and previously STICH trials indicated no clear link between the presence of viable myocardium and revascularization effects in patients with heart failure. Moreover, detecting areas of non-functioning myocardium that are deemed viable was not predictive of clinical events in the follow-up. This being said, the amount of scar tissue on CMR was a predictor of both LV functional recovery and clinical events in the follow-up, thus potentially shifting focus from the concept of hibernating myocardium towards understanding the sources and prognostic implications of scar tissue in patients with heart failure.
Second, recent trials in patients with chronic coronary disease, including ISCHEMIA and FAME 2 trials, although failing to show mortality benefit of revascularization, did signal a reduction in the rate of spontaneous myocardial infarction. The latter finding was replicated in the REVIVED trial. Given the above described prognostic relevance of scar tissue, preventing coronary events that may lead to formation of myocardial scarring seems to present an opportunity to improve patient prognosis.
Overall, the viability sub-study of the REVIVED trial seems to further challenge the concept of hibernating myocardium as a decision tool when considering revascularization in heart failure. On the other side, the extent of scar tissue did provide prognostic information.
Focusing on myocardial scarring in patients with HF and CAD may bring us back to two fundamental questions from the everyday practice of an interventional cardiologist:
- which patients with chronic coronary disease will benefit from PCI,
- and how can we reduce infarct size and post-infarct scar formation in the era of primary PCI.
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