Prior Atherosclerosis Ups the Risk of Dying After Acute MI

Patients with preexisting atherosclerosis are at an increased risk of death in the years following an acute MI when compared with those lacking a previous manifestation of the disease, a new analysis shows.

Using data from the FAST-MI registry, investigators showed that acute MI patients with a prior diagnosis of atherosclerosis had an 80% higher risk of death at 3 years (P < 0.001).

The French study, led by Etienne Puymirat, MD (Hôpital Européen Georges Pompidou, Paris, France), also showed that individuals with a prior MI had a 32% increase in risk of death at 3 years following the index event versus those without a prior infarction (P = 0.048). The risk associated with this history was attenuated among patients on statin therapy at the time of the recurrent (index) event.

Ajay Kirtane, MD (Columbia University Medical Center, New York, NY), who was not involved in the present study, told TCTMD that patients with a prior manifestation of atherosclerotic cardiovascular disease represent a higher-risk group in whom the absolute risk reductions for secondary preventive strategies would be larger when compared with patients undergoing primary prevention.

“In a sense, these data validate the need to be more aggressive among patients with established atherosclerotic risk,” said Kirtane.

In the paper, which was published online December 2, 2016, in the American Journal of Cardiology, the researchers note that mortality following acute MI has declined significantly over the last two decades. For this analysis of FAST-MI, they identified 3,079 acute MI patients, including 1,062 with a history of cardiovascular atherosclerotic disease and 498 with a prior MI. Patients with atherosclerosis and/or prior MI were older, had higher cardiovascular risk profiles, and more comorbidities than those without a previous history.

Three years after the acute MI, survival rates were significantly higher in patients without known atherosclerotic disease compared with those with atherosclerosis and this survival difference was evident as early as 1 year. Among those who survived to hospital discharge after the index acute MI, the 3-year mortality rate was also higher among those with atherosclerotic disease. Again, this difference was evident at 1 year.   

For patients taking a statin prior to index MI, the 3-year survival rate was 79% for those with a history of MI and 83% for those without a prior event, a difference that was not statistically significant.

“Patients who have had an MI are at increased risk for recurrent ischemic events and mortality, which suggests that this population may derive particular benefit from intensive secondary prevention,” state Puymirat and colleagues. “Several methods can be considered to improve the outcome of patients with recurrent events of multiple territories involved by the atherosclerotic process. In particular, a stronger antiplatelet regimen, or a higher intensity lipid lowering treatment.”

The researchers note that the IMPROVE-IT study showed the addition of ezetimibe (Zetia, Merck/Schering-Plough) to statin therapy significantly decreased the risk of major cardiovascular events compared with statin monotherapy in ACS patients. Subgroup analyses performed by the IMPROVE-IT researchers did not address whether those with a prior MI or previous manifestations of atherosclerosis had a benefit with more aggressive LDL lowering. 

Regarding the PCSK9 inhibitors, two large cardiovascular studies—FOURIER and ODYSSEY-Outcomes—are also testing whether additional LDL-lowering reduces the risk of cardiovascular morbidity and mortality after ACS, although whether the effect will differ in patients with or without a previous MI/atherosclerosis is only speculative at this point, write Puymirat and colleagues.