May 14, 2020
ISCHEMIA Substudy Evaluates Patients With Intermediate Left Main CAD
May 14, 2020—Findings from a substudy of the ISCHEMIA trial showed that patients with intermediate left main disease (LMD) have a greater risk of cardiovascular events compared with patients without intermediate LMD. The Society for Cardiovascular Angiography and Interventions (SCAI) announced that the study was presented as featured clinical research during the SCAI 2020 Scientific Sessions Virtual Conference held May 14–16.
According to SCAI, the presence of LMD provokes both emotional and evidence-based concerns that have resulted in patients with LMD being excluded from trials of revascularization versus medical therapy (excepting trials done in the 1980s). ISCHEMIA also excluded patients with LMD but allowed patients with intermediate LMD (25%–49%). The outcomes of these patients and the effect of invasive versus conservative strategy previously has not been explored before.
SCAI summarized the study in the announcement. Randomized ISCHEMIA trial participants who underwent coronary CTA (CCTA) at baseline were categorized into those with (25%–49%) and without (< 25%) intermediate LMD as determined by a core lab. The study excluded patients with LMD ≥ 50%, those with previous coronary artery bypass graft surgery, and those with nonevaluable or missing data on LM stenosis. Both clinical and quality-of-life outcomes in those with and without intermediate LMD were compared, as well as outcomes of participants randomized to an initial invasive versus conservative strategy.
ISCHEMIA randomized 5,179 participants to an initial invasive or conservative strategy. Those patients who underwent CCTA composed the LMD substudy cohort.
Among the 3,913 participants who underwent CCTA, 3,699 satisfied the inclusion criteria. Of these participants, 962 (26%) had intermediate LMD, and 2,737 (74%) did not. Among invasive-strategy participants with intermediate LMD, 7% had significant LM stenosis on invasive angiography.
The investigators reported that the primary outcome event rate was significantly higher in those with intermediate LMD versus those without intermediate LMD (adjusted hazard ratio, 1.31; 95% CI, 1.06–1.61; P = .0123).
“Our study showed that when compared with patients without intermediate LMD, those with intermediate LMD had worse outcomes,” commented lead author Sripal Bangalore, MD, in the SCAI announcement. “However, there was no treatment interaction such that the outcomes with invasive versus conservative were similar whether or not the patient had intermediate LMD on CCTA.”