Histologic atherosclerotic plaque characteristics are associated with restenosis rates after endarterectomy of the common and superficial femoral arteries

Objectives

This study assessed the predictive value of histologic plaque characteristics for the occurrence of restenosis after femoral artery endarterectomy.

Background

It would be advantageous if patients at increased risk for restenosis after arterial endarterectomy could be identified by histologic characteristics of the dissected plaque. Differences in atherosclerotic plaque composition of the carotid artery have been associated with restenosis rates after surgical endarterectomy. However, whether atherosclerotic plaque characteristics are also predictive for restenosis in other vascular territories is unknown.

Methods

Atherosclerotic plaques of 217 patients who underwent a common femoral artery endarterectomy (CFAE; n = 124) or remote superficial femoral artery endarterectomy (RSFAE; n = 93) were examined and scored microscopically for the presence of collagen, macrophages, smooth muscle cells, lipid core, intraplaque hemorrhage, and calcifications. The 12-month restenosis rate was assessed using duplex ultrasound imaging (peak systolic velocity [PSV] ratio ≥2.5).

Results

The 1-year restenosis rate was 66% (61 of 93) after RSFAE compared to 21% (26 of 124) after CFAE. Plaque with characteristics of high collagen and smooth muscle cell content were positively associated with the occurrence of restenosis, with odds ratios (ORs) of 2.90 (95% confidence interval [CI], 1.82-4.68) and 2.20 (1.50-3.20) for superficial femoral artery (SFA) and common femoral artery (CFA), respectively. SFA plaques showed significantly heavier staining for collagen (69% vs 31% for CFA; P < .001) and smooth muscle cells (64% vs 36% for CFA; P < .001). After multivariate analysis, the operation type (CFAE or RSFAE), gender, and the presence of collagen were independent predictive variables for restenosis after endarterectomy of the CFA and SFA.

Conclusion

Plaque composition of the CFA and SFA differs. Furthermore, the dissection of a fibrous collagen-rich plaque is an independent predictive variable for restenosis after endarterectomy of the CFA and SFA.