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More sophisticated imaging does not necessarily mean better outcomes in ischemic heart failure

NEW ORLEANS — Advanced imaging fell short overall in heart failure (HF) patients who needed further definition of ischemia or viability, although select patients appeared to see some benefit, according to the AIMI-HF study.

The study’s primary endpoint — a composite of cardiac death, myocardial infarction (MI), resuscitated cardiac arrest, or cardiac hospitalization — occurred in a similar 31% of patients who underwent expanded imaging and 35% in the group who underwent standard single care had undergone. Photon emission CT (SPECT) imaging (HR 0.95, 95% CI 0.71-1.25), reported Lisa Mielniczuk, MD, of the University of Ottawa Heart Institute in Canada.

Also, advanced imaging, which consisted of cardiac MRI (CMR) or PET, did not result in a lower incidence of the primary endpoint in patients evaluated for ischemia (HR 0.86, 95% CI 0.61-1.21 ), she explained in a presentation at the annual meeting of the American College of Cardiology (ACC).

However, within the ischemia cohort, “there was a marginally significant reduction in cardiac death in patients with PET imaging compared to SPECT,” said Mielniczuk, at 11% versus 18.6% (HR 0.61, 95% CI 0.38 -1.00, P=0.049).

And more patients with CMR or PET received early revascularization compared to those who underwent SPECT (32% vs. 12%, P<0.0001).

For “Patients with symptomatic heart failure and reduced left ventricular function, if you look for ischemia or signs of viability and then respond to revascularization, you can improve outcomes,” Edward Fry, MD, of Ascension Health’s Cardiovascular Service Line in Indianapolis and ACC President 2022-2023, explained MedPage today.

“The question in this study is, when you compare advanced imaging to what is considered standard imaging with SPECT, are the results superior?” Fry noted. Given that advanced imaging offers better resolution and more high-level information, it’s reasonable to assume that the results would affect outcomes, he noted.

“Because this study failed to meet some of the statistical endpoints, I’m not sure it will transform clinical practice,” said Fry, who was not involved with the study. He added that “some of the subgroup analyzes are consistent with what many people would believe” that advanced imaging leads to earlier revascularization, so the study shows trends, if not statistical significance.

For example, in the ischemia cohort, the cumulative incidence of the primary endpoint was not significantly lower in those who underwent early revascularization:

  • Early revascularization: HR 0.52 (95% CI 0.23-1.15)
  • No early revascularization: HR 0.93 (95% CI 0.64-1.36)

“If you had ischemia and had advanced imaging, you did better, but the total number of events was low,” Fry said. “It’s about finding the patients who have heart failure due to ischemic disease and finding the patients who would benefit from revascularization — that’s an age-old question.”

The Alternative Imaging Modalities in Ischemic Heart Failure (AIMI-HF) study was conducted at 15 international sites, most of them in Canada, but also in Finland, South America and one site in the United States

A total of 1,069 patients underwent enhanced imaging with CMR or PET and 312 underwent standard imaging with SPECT. About 85% were males, the median age was 66-68 years, and over 60% were smokers.

Eligible patients had known or suspected coronary artery disease documented by angiography, prior MI, moderate ischemia, or scar with New York Heart Association (NYHA) class II-IV symptoms and an ejection fraction below 45%, or NYHA class I symptoms and a Ejection fraction below 30%.

A total of 271 patients were randomized, while patients who met the study inclusion criteria but were not randomized due to clinical management decisions and still received imaging were enrolled in one registry arm. Propensity score matching was used to adjust for differences in baseline characteristics, study location, and randomization compared to the registry. The patients were followed for 36 months.

Notably, the prescription rates for mineralocorticoid receptor antagonists and ACE inhibitors/angiotensin receptor blockers were low in the study, which began recruiting in 2011 and ended in 2020. As a result, the medical therapy was not representative of current clinical practice, Mielniczuk said. This and the small number of patients in the randomized group were noted as limitations of the study.

disclosure

Mielniczuk and Fry disclosed no industry ties.

Main source

American College of Cardiology

Citation: Mielniczuk L, et al “Ischemia and viability imaging in heart failure: The alternative imaging modalities in the Ischemic Heart Failure Study (AIMI-HF): IMAGE-HF Project 1A” ACC 2023.

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