The ISCHEMIA study keeps providing scientific news. This work in patients with stable coronary artery disease had already shown (to our surprise) that ischemic burden does not predict 4-year mortality.
Now, this new analysis suggests that anatomic severity can predict events. However (surprisingly, once more), altering this severity through angioplasty does not change the prognosis for hard points such as death or infarction (referring to 4 years of follow-up).
Perhaps only the subgroup with greater anatomical severity somewhat benefits from angioplasty in terms of a reduction in death and infarction rates.
A total of 5179 patients with moderate to severe ischemia were randomized to an initial invasive strategy vs. a conservative strategy. An independent, blinded laboratory interpreted the extent and severity of coronary artery disease on computerized tomography (CT).
When comparing patients with no ischemia or mild ischemia vs. those with moderate or severe ischemia, no mortality increase was observed among the latter (moderate ischemia hazard ratio [HR]: 0.89; 95% confidence interval [CI]: 0.61 to 1.30; severe ischemia HR: 0.83; 95% CI: 0.57 to 1.21; p = 0.33).
The rate of non-fatal infarction increased with ischemia severity, although this is only a trend that becomes non-significant when adjusting for all variables.
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This is very different from what was observed with the burden of coronary disease, given that, when comparing the extremes (no disease or mild disease vs. moderate or severe disease) there was almost a 3-fold increase in mortality (HR: 2.72; 95% CI: 1.06 to 6.98), and an almost 4-fold increase in infarction (HR: 3.78; 95% CI: 1.63 to 8.78).
The ischemic burden was not an indicator to select patients who might benefit from revascularization. In contrast, those with more severe anatomic disease (n = 659) who underwent revascularization showed a decrease in cardiovascular death and infarction at 4 years of follow-up (a difference of 6.3%; CI 95%: 0.2% to 12.4%). The difference only affected cardiovascular death, since all-cause death rates were similar.
Conclusion
Ischemia severity was not associated with increased risk, in contrast to what occurred with anatomy, where greater disease severity did translate into increased risk.
The initial invasive strategy did not decrease events across the spectrum of ischemic burden severity after 4 years of follow-up.
CIRCULATIONAHA-120-049755Original Title: Outcomes in the ISCHEMIA Trial Based on Coronary Artery Disease and Ischemia Severity.
Reference: Harmony R. Reynolds et al. Circulation. 2021 Sep 28;144(13):1024-1038. doi: 10.1161/CIRCULATIONAHA.120.049755+.
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