Non-fibroatheroma lesion phenotype and long-term clinical outcomes: a substudy analysis from the PROSPECT study.

OBJECTIVES

The purpose of this study was to determine the clinical impact of non-fibroatheroma lesion phenotype in patients presenting with an acute coronary syndrome (ACS).

BACKGROUND

Although fibroatheromas (FAs) are known to be clinically unstable, the impact of non-FA lesion phenotype on clinical outcomes has not been studied.

METHODS

In the PROSPECT (Providing Regional Observations to Study Predictors of Events in the Coronary Tree) study, patients presenting with an ACS underwent 3-vessel grayscale and virtual histology intravascular ultrasound (VH-IVUS) after successful percutaneous intervention for all culprit lesions and were followed for 3 years. Patients were divided into those who had only the non-FA phenotype (pathological intimal thickening or fibrotic and/or fibrocalcific lesions) versus those who had at least 1 nonculprit FA.

RESULTS

Among 2,880 nonculprit lesions identified by VH-IVUS, 39.8% were non-FAs (1,042 pathological intimal thickening, 72 fibrotic, and 33 fibrocalcific). Nonculprit major adverse cardiac events (MACE) (death, myocardial infarction, or urgent rehospitalization for progressive or unstable angina) were attributed to only 7 non-FA lesions (0.7%) versus 43 FA lesions (2.7%, p < 0.001) during 3 years follow-up. Of 609 patients, 67 (11.0%) patients had only non-FA lesion phenotypes. Patients with only non-FAs tended to be younger and more often female, have fewer nonculprit lesions and less overall plaque burden and necrotic core, and fewer nonculprit lesion MACE compared with patients with at least 1 FA. In the adjusted Cox proportional hazards model, absence of a FA was a significant predictive of a lower 3-year nonculprit MACE rate (hazard ratio: 0.23; 95% confidence interval: 0.06 to 0.95).

CONCLUSIONS

Non-FA lesions were clinically stable and were rarely associated with clinical events during 3 years of follow-up. The intermediate-term prognosis in patients presenting with ACS in whom all nonculprit lesions are non-FAs is favorable. (

PROSPECT: An Imaging Study in Patients With Unstable Atherosclerotic Lesions; NCT00180466).