Improvements in ischemia and angina common in INOCA, but not correlated

Reuters Health - 16/06/2021 - In ischemia with no obstructive coronary-artery disease (INOCA), both ischemia and angina often get better over time, but the improvements may not be linked, according to results of the CIAO-ISCHEMIA study.

"Severity of ischemia and angina were not correlated in the INOCA patients or in the obstructive coronary-artery disease (CAD) patients at enrollment, and the change in ischemia was not significantly correlated with the change in angina over one year," said Dr. Harmony R. Reynolds of New York University (NYU) Grossman School of Medicine in New York City.

Treatment for INOCA patients is highly variable, Dr. Reynolds and her colleagues note in a paper in Circulation, with guidelines focusing on managing symptoms. A better understanding of the link between ischemia, symptoms, physical functioning and quality of life is needed, they argue.

In the international CIAO-ISCHEMIA study, the team aimed to describe the natural history of symptoms and ischemia in INOCA patients with a history of angina. The study, lasting from 2014 to 2019, grew out of a trial called ISCHEMIA, including patients with moderate to severe ischemia who did not have obstructive CAD and thus did not meet the criteria for randomization in that trial.

Compared with the 865 ISCHEMIA participants, the 208 INOCA patients enrolled in CIAO were significantly younger (median age, 63 vs. 66 years) and more often female (66% vs. 26%). The magnitude of ischemia in the two groups was similar, with a median of four ischemic segments in each, and the degree of ischemia and angina were not significantly linked at enrollment in CIAO (P=0.46) or in ISCHEMIA stress echocardiography participants (P=0.35).

At one year, half of the CIAO participants had normal stress echocardiograms, with a median number of ischemic segments of 0; only 23% had moderate or severe ischemia (three or more ischemic segments).

"Despite the relatively large amount of ischemia on stress echocardiography at enrollment, half of patients with INOCA in this study had a normal stress echocardiogram at one year," Dr. Reynolds said. "This was surprising because of the relatively large amounts of ischemia the CIAO patients had at enrollment."

Also at one year, the Seattle Angina Questionnaire (SAQ) Angina Frequency subscale score had improved by 10 or more points in 43% of INOCA participants, with 59% reporting no angina in the prior month; angina frequency worsened in 27 (14%).

"Angina improved in nearly half of patients, again showing the variability in the clinical syndrome of INOCA over time," Dr. Reynolds said.

The change in ischemia over one year was not significantly linked with the change in angina (rho=0.029), the researchers report.

"Previous studies examining this relationship did not include blinded review of ischemia testing, were smaller in size, and included either one site or just a few sites. The international, multi-center design of ISCHEMIA and the requirement for moderate or severe ischemia provided an opportunity to learn more about INOCA on a global scale," Dr. Reynolds said.

She noted that the research team did not identify any medication classes linked with improved ischemia or angina. "We did not perform invasive testing to confirm the presence of coronary artery spasm or microvascular coronary disease, but stress tests were read at a core laboratory without knowledge of CAD status or whether the test was an enrollment or a follow-up," she said.

Dr. Erin D. Michos, director of Women's Cardiovascular Health at Johns Hopkins University School of Medicine in Baltimore, Maryland, said she was not surprised by the findings.

"They reflect inherent sex differences in the complex relationships between angina, atherosclerosis, and ischemia," Dr. Michos, who was not involved in the research, told Reuters Health by email.

"Of the approximately 10,000,000 patients presenting each year with stable chest pain in the United States, fewer than 12% reveal evidence of obstructive CAD," she added. "INOCA particularly affects women much more commonly than men, as more than 90% of women presenting with chest pain concerning of ischemia have no obstructive CAD on angiography. Importantly, women with INOCA have worse outcome than those without evidence of ischemia, leading to more frequent hospitalizations and procedures."

"Multiple factors likely contribute to INOCA," Dr. Michos said. "Ischemia in the absence of obstructive CAD is complex, and we need further research in this area to elucidate mechanisms and improve our understanding of optimal treatments."

SOURCE: https://bit.ly/3ildypv Circulation, online June 1, 2021.

By Lorraine L. Janeczko



Posted on 16 June 202128 June 2021