SAN FRANCISCO—There is added accumulation of neointima, or so-called late catch-up, after six to nine months in patients who received drug-eluting stents (DES), according to an analysis presented this week at the 2009 Transcatheter Cardiovascular Therapeutics scientific meeting.
Kyung Woo Park, MD, from the department of internal medicine at the Seoul National University Hospital in South Korea, said that recent studies have suggested the possibility of delayed occurrence of late loss, which is often called the late catch-up phenomenon, after DES implantations. This occurrence has been found to be more common in "limus" DES.
However, Park noted that there are limited data available on whether late catch-up exists in DES, such as sirolimus- (Cordis’ Cypher) or paclitaxel-eluting stents (Boston Scientific’s Taxus).
To address this issue, researchers performed a serial quantitative coronary angiographic analysis of lesions for which there were two or more angiographic follow ups available at least one year apart from one another after the implantation of DES. They routinely recommended that the first (early) angiographic follow up occur at six to nine months post PCI and the second (late) angiographic follow up be performed at 18 to 24 months post PCI.
The investigators excluded all lesions that received target lesion revascularization at first follow up. Also, they defined early luminal loss as the difference in minimal luminal diameter between the first angiographic follow up and immediate post PCI, while delayed luminal loss was defined in minimal luminal diameter between second and first angiographic follow up.
Park said that he and his colleagues indentified 412 lesions in 307 patients, 128 lesions in the Taxus group and 284 lesions in the Cypher group, whose PCI was performed from January 2004 to December 2006.
“As expected, the early luminal loss in-stent was significantly higher in the Taxus group compared with the Cypher group [0.56 vs. 0.20 mm],” according to Park.
However, the researchers found that the delayed luminal loss that occurred after the first angiographic follow up was significantly higher in the Cypher group (0.10 vs. 0.28 mm), suggesting that occurrence of delayed late loss was more prominent in Cypher stents.
On correlation analysis, in contrast with Taxus stents where early luminal loss showed the best correlation with total luminal loss (correlation coefficient 0.81 vs. 0.30 for early vs. late luminal loss), delayed luminal loss showed the best correlation with total luminal loss in Cypher stents (correlation coefficient 0.42 vs. 0.91 for early vs. delayed luminal loss).
These findings suggest that the luminal loss occurring after the first angiographic follow up “better explains” the total luminal loss in Cypher stents, according to Park.
Based on the researchers' observations, Park noted that late catch-up does seem to exist in the six to nine months following PCI with DES, and the occurrence of delayed late loss seems to be more prominent in Cypher compared with Taxus stents.