Introduction: Previous studies have suggested that angiographically detected peri-stent contrast staining (PSS) after stent implantation is a strong predictor of subsequent target lesion revascularization (TLR) and very late stent thrombosis (VLST). However, the natural history of PSS, and its clinical significance remains unknown.
Methods: The study sample comprised 8,720 de novo lesions that were treated with coronary stents and were evaluated by follow-up angiography within 2 years after stent implantation in a single center. Late acquired PSS was observed in 267 lesions (3.1%), and of those, 103 lesions that underwent second follow-up angiography were enrolled in the analysis. PSS was defined as contrast staining outside the stent contour extending to >20% of the stent diameter measured by quantitative coronary angiography. Morphological features of PSS were classified into 3 groups as follows: monofocal, multifocal, or segmental. The natural history of PSS can be classified into 4 categories based on the serial change of PSS size; enlarged, reduced, unchanged, and resolved.
Results: At the second angiographic follow-up study, the size of PSS enlarged in 23 (22%), reduced in 25 (24%), unchanged in 25 (24%), and resolved in 30 (29%) lesions, respectively. The average follow-up period after the index angiographic follow-up study was 83±32 months. The cumulative incidence of TLR was significantly higher in the resolved group than in the enlarged, reduced, and unchanged groups (37%, 13%, 16%, and 24%, respectively, p=0.04). The overall incidence of VLST was 4%, and most VLST occurred in lesions with multifocal PSS at the index follow-up study compared to those with monofocal and segmental PSS (14%, 2%, and 0%, respectively, p=0.04). However, the cumulative incidence of VLST was similar among each category for serial change of PSS.
Conclusions: Most PSS observed within 2 years after stenting tended to reduce in size, and seemed to be associated with subsequent TLR especially, when it was resolved. The multifocal appearance of PSS appeared to be associated with a higher risk for subsequent VLST. This easily assessable angiographic morphology is useful in clinical risk stratification for patients who underwent stent implantation.