Angioscopy study from a large patient population comparing sirolimus-eluting stent with biodegradable versus durable polymer.

AIMS: This study aimed to compare the neointimal coverage (NIC), subclinical thrombus, color of plaque underneath the stent at 9-month after implantation of sirolimus-eluting stent (SES) either with durable or with biodegradable polymer (BDPM).

METHODS: A total of 175 patients were assigned as Cypher (n = 81, 97 stents with durable polymer) and Excel (n = 94, 112 stents with BDPM) stent at 9-month after indexed procedure. NIC was classified from grade 0-3. Color of plaque was divided into white, light-yellow, yellow, and dark yellow. Thrombus was diagnosed as white or red material with cotton-like or ragged appearance. Incomplete NIC (grade 0/1) circled by a blush was termed by "inflaming."

RESULTS: There were significant differences in unstable angina (90.5 vs. 52.4%, P = 0.015), previous myocardial infarction (33.3 vs. 4.0%, P = 0.045) and left ventricular eject fraction (55.2 ± 7.8 vs. 62.6 ± 6.3%, P = 0.021) between the Excel and Cypher groups. The minimal- and maximal-NIC grades in the Cypher group were 0.67 ± 0.58 and 2.29 ± 0.46, respectively, when compared with 1.45 ± 0.67 (P < 0.001) and 2.64 ± 0.49 (P = 0.023) in the Excel group. The percentage of yellow plaque, thrombus, "inflaming" and NIC grade of 0 in the Excel and Cypher groups, respectively, were as follows: 8.0 vs. 26.8% (P = 0.031), 9.8 vs. 32.9% (P = 0.024), 8.0 vs. 38.1% (P = 0.017), and 38.1 vs. 0% (P < 0.001). Of the stents with "inflaming," 63.6% had thrombus when compared with 20.1% of the non-erosion stents (P < 0.001). Overlapping segments had the lowest NIC grades and more "inflaming" demonstrating a significant difference between Cypher vs. Excel stents. NIC grade was positively correlated with thrombus.

CONCLUSIONS: SES with BDPM has improved NIC resulting in less yellow plaque, thrombus, and "inflaming." Overlapping segments had the lowest NIC grade and more "inflaming."