There has been an increase in the diagnosis of patients with proven ischemia who did not present obstructive coronary lesions (defined as the absence of stenosis ≥50%), called ischemia with non-obstructive coronary arteries (INOCA). These patients are at a higher risk for major adverse cardiac events (MACE) compared with the rest of the population.
The ISCHEMIA trial, one of the most relevant trials in recent years, enrolled patients with moderate to severe ischemia as evidenced in functional testing and randomized them to clinical treatment vs. angioplasty. However, 21% of enrolled patients did not present obstructive coronary disease in the baseline computed tomography angiography and, therefore, were not included in the final randomization.
The aim of this analysis of the ISCHEMIA trial was to characterize patients with INOCA in terms of clinical characteristics and ischemia degree.
The ischemia-evoking methods used were myocardial perfusion study (PET), stress echocardiogram, and magnetic resonance imaging. Ischemia severity was determined in an independent central lab (Core Lab). Patients who did not undergo computed tomography angiography or who had undergone prior myocardial reperfusion surgery or coronary angioplasty were excluded.
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Out of the 4211 initial participants, 688 did not have coronary obstruction ≥50% detected with tomography (16.3% INOCA). Additionally, 212 patients with mild or no ischemia were excluded, so the final analyzed cohort included 476 patients. Among patients with INOCA, 27.3% had normal coronary arteries, and the rest presented some degree of stenosis.
When comparing patients with significant coronary obstruction, patients with INOCA and moderate to severe ischemia were younger (mean age: 60 vs. 63 years old; p < 0.001) and most of them were female (53.6% vs. 20.6%; p < 0.001). The highest proportion of patients with INOCA was found among those with moderate ischemic burden.
The INOCA diagnosis odds ratio between female patients compared with male patients was 4.2 (95% confidence interval: 3.4-5.2; p < 0.001). When analyzing the differences in non-obstructive disease in terms of sex, the number of segments and the involvement score were higher in male subjects (p < 0.001).
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A multivariate analysis was conducted. A diagnosis of non-obstructive disease was associated with younger, female, non-diabetic patients, with no prior AMI and lower severe ischemia index.
Conclusions
In this analysis of patients enrolled in the ISCHEMIA trial, INOCA was observed in 13% of them, meaning that, when evaluating patients with moderate to severe ischemia, it is paramount to consider ischemia-causing variables other than clear atherosclerosis, namely microvascular dysfunction, reduced flow reserve, coronary spasms, etc.
Dr. Omar Tupayachi.
Member of the Editorial Board of SOLACI.org.
Original Title: Ischemia With Non obstructive Coronary Arteries.
Font: Reynolds HR, Diaz A, Cyr DD, Shaw LJ, Mancini GBJ, Leipsic J, Budoff MJ, Min JK, Hague CJ, Berman DS, Chaitman BR, Picard MH, Hayes SW, Scherrer-Crosbie M, Kwong RY, Lopes RD, Senior R, Dwivedi SK, Miller TD, Chow BJW, de Silva R, Stone GW, Boden WE, Bangalore S, O’Brien SM, Hochman JS, Maron DJ; ISCHEMIA Research Group. Ischemia With Nonobstructive Coronary Arteries: Insights From the ISCHEMIA Trial. JACC Cardiovasc Imaging. 2022 Sep 13:S1936-878X (22)00406-5. doi: 10.1016/j.jcmg.2022.06.015. Epub ahead of print. PMID: 36115814.
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