Post-MPI statin use prevents MACE in patients with elevated coronary artery calcium score

Use of moderate- to high-intensity statins (MHIS) after myocardial perfusion imaging (MPI) leads to significantly fewer major adverse cardiovascular events (MACE) and is an independent negative predictor for 24-months MACE among patients with normal MPI and coronary artery calcium (CAC) score >300, a Singapore study has shown.

“Physicians should be proactive in starting MHIS in these patients, despite the apparently reassuring stress MPI results,” the researchers said.

Between 1 March 2016 and 31 January 2017, Yi Hui To and colleagues from National University Singapore, Tan Tock Seng Hospital, and Yangon General Hospital conducted a retrospective review of normal MPI with CAC score >300 in a Singapore tertiary hospital.

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

Of the 311 eligible patients (median age 71 years, 56.3 percent male), 65.0 percent were on MHIS following MPI. Participants in the post-MPI group had significantly lower MACE (3.5 percent vs 9.2 percent; p=0.035). [Singapore Med J 2022;doi:10.11622/smedj.2022018]

Univariate analysis showed post-MPI use of MHIS as 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 even after multivariate adjustment (adjusted OR, 0.363, 95 percent CI, 0.134‒0.984; p=0.046).

“The benefits of intensive statin therapy in patients with stable coronary disease are already well known,” the researchers said. “This is likely related to multiple 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]

Another important observation in the current study was the fact that MACE only correlated with post-MPI, and not pre-MPI, status. MACE decrease due to preventive therapy initiation after knowledge of scan results, however, was not a novel finding.

For instance, a post hoc analysis of the Scottish Computed Tomography of the Heart trial revealed that MACE reduction was attributed to the start of preventive therapies in patients with nonobstructive plaque. [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-e350]

Antiplatelet medications are frequently prescribed for primary prevention. In the present study, however, neither baseline nor post-MPI antiplatelet use was a significant factor affecting MACE.

The current findings are consistent with those of recent primary prevention trials, which show the lack of benefit with antiplatelets, and support the latest guidelines in recommending against routine aspirin use. [J Am Coll Cardiol 2019;74:e177-e232]