Peripheral Artery Disease: Incidence and Outcomes of Myocardial Infarction

Myocardial infarction (MI) was associated with an increased risk of hospitalization for acute limb ischemia events and cardiovascular death, and 4.9% of patients with peripheral artery disease (PAD) experienced MI within a median follow-up time period of 30 months, according to a study published in JAMA Cardiology.

The current study is a secondary analysis of the randomized, double-blind, clinical trial Study Comparing Cardiovascular Effects of Ticagrelor and Clopidogrel in Patients With Peripheral Artery Disease (EUCLID, ClinicalTrials.gov Identifier: NCT01732822). The EUCLID trial followed 13,885 participants (72.0% male, median age 66 [60-73] years) on clopidogrel or ticagrelor monotherapy for a median follow-up period of 30 months.

For the current analysis, researchers evaluated the incidence and type of MI among these patients during follow-up to determine the association of MI with acute limb ischemia and cardiovascular mortality.

MI events were classified as types 1, 2, 3, 4a, 4b, or 5 (spontaneous, secondary, sudden cardiac death, <48 hours after percutaneous coronary intervention, definite stent thrombosis, and <72 hours after coronary artery bypass graft, respectively).

Stepwise selection was used to develop a multivariate regression model identifying factors associated with MI, and a multivariate, time-dependent Cox regression analysis was used to identify the associations of MI with acute limb ischemia hospitalizations and cardiovascular death.

Of the total patient population, 683 (4.9%) experienced MI during the follow-up period, for an average of 2.4 events per 100 patient-years. 

These patients were older (median age 69 [62-75] years vs 66 [60-72] years) and more likely to have a previous lower extremity revascularization (68.2% [466 of 683] vs 56.1% [7409 of 13,202]) or diabetes (51.1% [349 of 683] vs 37.8% [4996 of 13,202]) than patients who did not experience MI.

Most events were type 1 (59.3%, n=405), followed by type 2 (34.6%, n=236). Few events were types 3, 4a, 4b, or 5 (1.8%, 2.0%, 1.6%, and 0.7%, respectively).

After randomization, MI was independently associated with hospitalizations for acute limb ischemia (adjusted hazard ratio [HR], 2.5; 95% CI, 1.3-5.0; P =.008) and cardiovascular death (adjusted HR, 9.0; 95% CI, 7.3-11.2; P <.001).

“More research is needed to identify therapies to reduce the risk of MI in patients with PAD and to improve management of type 2 MI,” the study authors concluded.

Reference

Olivier CB, Mulder H, Hiatt WR, et al. Incidence, characteristics, and outcomes of myocardial infarction in patients with peripheral artery disease insights from the EUCLID trial [published online December 12, 2018]. JAMA Cardiol. doi: 10.1001/jamacardio.2018.4171