Patients with acute coronary syndrome (ACS) and diabetes who have thin-cap fibroatheromas  ≥1 had a higher rate of major adverse cardiac events (MACE) caused by medically-treated non-culprit lesions after 3 years, according to an analysis of the PROSPECT (Providing Regional Observations Study Predictors of Events in the Coronary Tree) study.

Elvin Kedhi, MD, PhD, of Isala Klinieken in Zwolle, Netherlands, and colleagues conducted the analysis to investigate the relationship between thin-cap fibroatheromas. The results were published in JACC: Cardiovascular Imaging.

Using 3-vessel radiofrequency intravascular ultrasound, the researchers discovered that lesions have features consistent with vulnerable plaques, including thin-cap fibroatheromas. Therefore, the researchers measured the incidence of non-culprit lesion-MACE in 2 prospectively-matched groups according to the presence of  thin-cap fibroatheromas and diabetes.


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A total of 697 patients were included in the study, 17.7% had diabetes. The 3-year MACE rate was 29.4% in patients with diabetes compared with 18.8% in patients without diabetes (P=.01). The non-culprit lesion-MACE rate was also significantly higher among patients with diabetes compared with those without (18.7% vs 10.4%; P=.02).

Propensity score matching created 2 balanced groups, consisting of 82 patients each, with and without diabetes. Among the patients with diabetes, thin-cap fibroatheromas ≥1 was associated with higher non-culprit lesion–MACE at 3 years compared with patients without  thin-cap fibroatheromas (27.8% vs 8.9%; hazard ratio [HR]: 3.56; 95% confidence interval [CI]: 0.98-12.96; P=.04).

In addition, patients with diabetes without thin-cap fibroatheromas  had a similar 3-year rate of NCL-MACE as patients without diabetes (8.9% vs 8.9%; HR: 1.09; 95% CI: 0.27-4.41; P=.90).

“The present study has potential implications for the therapeutic approach to patients with DM [diabetes mellitus],” the authors wrote. “In the setting of complex multivessel disease, CABG is an excellent option as it bypasses many untreated vulnerable non-culprit lesionss in the same territories as the ischemic culprit lesions. CABG is not an optimal solution, however, for vessels with only non-ischemic but otherwise high-risk non-culprit lesions, due to the high risk of graft occlusion from competitive flow.”

The authors noted that based on the results of the analysis, the presence of an untreated thin-cap fibroatheroma is associated with a very high MACE rate after 3 years, which would explain the poor prognosis of the high-risk diabetic cohort.

“Considering the increasing global prevalence of DM, further studies are warranted to determine whether identification of vulnerable plaques by either intravascular or noninvasive imaging in high-risk DM patients might inform more accurate prognosis and improved decision-making as regards potent medical therapies and strategies for revascularization,” they stated.

Reference

Kedhi E, Kennedy MW, Maehara, et al. Impact on thin-cap fibroatheromas on unanticipated ischemic events in medically-treated patients with diabetes mellitus: insights from the PROSPECT study. JACC Cardiovasc Imag. 2016. doi:10.1016/j.jcmg.2015.12.023.