Symptoms and stress test results change over time in patients with ischemia with no obstructive coronary artery disease (INOCA), according to results from the CIAO-ISCHEMIA study presented March 30 during a Late-Breaking Clinical Trial session during ACC.20/WCC.

"The results suggest the disease activity ebbs and flows – there may be periods of time when symptoms are more active and times when they are absent," says Harmony R. Reynolds, MD, FACC, the study's lead author.

Reynolds and colleagues enrolled 208 people who were screened for the ISCHEMIA trial and were found to have a blockage of less than 50% on coronary angiography, making them ineligible for the large international trial.

The researchers assessed participants' symptoms and stress test results at one year and compared CIAO patients' baseline findings with those of 1,079 patients enrolled in ISCHEMIA who had a stress echocardiogram.

At baseline, the two groups of patients had similar amounts of ischemia on their stress tests, even though patients in CIAO did not have obstructive CAD.

CIAO participants with INOCA had more frequent angina; 17% of these patients had angina weekly or more often, compared with 4% among those in ISCHEMIA. CIAO patients were also more likely to have angina in the previous month; 41% of CIAO patients with INOCA reported no angina in the last month compared to 62% of ISCHEMIA patients with CAD.

At one year, in patients in CIAO, stress echocardiograms became normal in about half of patients and in 45% they were the same as at baseline or worse. Angina symptoms improved in 42% and worsened in 14%, and the number of medications to control angina on average remained the same. The change in stress test findings over one year and the change in symptoms over one year were not related.

Notably, in CIAO 66% of patients are women, compared with only 26% in ISCHEMIA. Previous studies have also found that women are more likely to experience chest pain symptoms and have abnormal stress test results than men despite showing less extensive plaque buildup in the arteries.

"This could relate to fundamental differences in how heart disease develops in women and men," Reynolds says. For example, prior studies have suggested women are more likely to experience small vessel disease, in which the smaller blood vessels restrict blood flow to the heart even if the main arteries are clear.

"The worry is that patients with INOCA will get the brush-off from doctors, who might believe patients are fine because their arteries are open," Reynolds adds. "However, they cannot be ignored. Prior studies show that these patients are at higher risk than people without angina, although they are generally at lower risk than those with obstructive CAD."

Further research is needed to determine the factors that contribute to such symptoms in the absence of CAD and determine appropriate treatment approaches, she says. The researchers plan to compare different heart disease assessment strategies to clarify how less invasive tests can be used to identify patients at higher risk.

Clinical Topics: Diabetes and Cardiometabolic Disease, Dyslipidemia, Heart Failure and Cardiomyopathies, Invasive Cardiovascular Angiography and Intervention, Noninvasive Imaging, Prevention, Stable Ischemic Heart Disease, Acute Heart Failure, Interventions and Imaging, Echocardiography/Ultrasound, Chronic Angina

Keywords: ACC Annual Scientific Session, acc20, Echocardiography, Stress, Ischemia, Angina, Stable, Percutaneous Coronary Intervention, Dyslipidemias, Primary Prevention, Heart Failure

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