Statins reduce MACE in patients with normal MPI, elevated CAC score

Use of moderate to high-intensity statin (MHIS) following myocardial perfusion imaging (MPI) results in fewer major adverse cardiovascular events (MACE) and is independently predictive of 24-month MACE among patients with normal stress MPI and coronary artery calcium (CAC) score >300, a Singapore study has shown.

“[P]atients with CAC >300 are at significant risk of MACE at 24 months after normal stress MPI,” the researchers said. “Physicians should be proactive in starting MHIS in these patients, despite the apparently reassuring stress MPI results.”

The research team performed a retrospective review of normal MPI with CAC score >300 between 1 March 2016 and 31 January 2017 in a Singapore tertiary hospital. They did not include patients with known atherosclerotic cardiovascular disease or left ventricular ejection fraction <50 percent on MPI.

Using electronic records, the researchers assessed patient demographics, prescriptions, and MACE (ie, cardiac death, nonfatal myocardial infarction, and/or ischaemic stroke) at 24 months after MPI. They also examined the independent predictors of MACE using binary logistic regression.

A total of 311 patients (median age 71 years, 56.3 percent male) were included, of whom 65.0 percent were on MHIS after MPI. Rates of MACE were significantly lower in the post-MPI MHIS group (3.5 percent vs 9.2 percent; p=0.035). [Singapore Med J 2023;64:109-114]

On univariate analysis, post-MPI use of MHIS turned out to be the only significant predictor for MACE (odds ratio [OR], 0.355, 95 percent confidence interval [CI], 0.131‒0.962; p=0.042). This finding persisted after multivariate adjustment (adjusted OR, 0.363, 95 percent CI, 0.134‒0.984; p=0.046).

“Our data showed that patients on MHIS after MPI have a lower 24-month MACE than those without MHIS,” the researchers said. “Post-MPI MHIS use also emerged as the only significant predictor of 24-month MACE.”

Statin actions

Earlier studies have reported the benefits of intensive statin therapy in patients with stable coronary disease, which are likely associated with several statin actions such as reduced arterial inflammation, decreased plaque volume, and overall increase in atherosclerotic plaque stability. [N Engl J Med 2005;352:1425-1435; Heart 2019;105:567-578]

“The fact that MACE is only related to the post-MPI (and not the pre-MPI) MHIS status in our study is an important observation, although MACE reduction owing to preventive therapy being started after knowledge of scan results is not a new finding,” the researchers said.

In a previous trial, MACE reduction in the computed tomography angiography group was believed to be the result of preventive therapy initiation in patients with nonobstructive plaque since the rates of invasive coronary angiography did not differ between groups. [J Am Coll Cardiol 2016;67:1759-1768]

“Our results underscore the importance of starting MHIS in response to elevated CAC, even when the stress MPI is normal,” the researchers said.

“These findings add to the wealth of data behind the use of CAC in guiding statin use, consistent with the most recent guidelines recommending CAC measurement when a decision about statin therapy is uncertain and initiation of statins when CAC is at least 100,” they added. [J Am Coll Cardiol 2019;73:e285-350]