TCT: Differences in outcomes of Cypher vs. PTCA still not CRISTAL clear

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The use of a Cypher Select stent (Cordis) compared to percutaneous transluminal coronary angioplasty (PTCA) produced similar results in regard to late lumen loss in patients treated for restenosis; however, the Cypher stent trumped PTCA for levels of follow-up minimum lumen diameter (MLD), acute gain and net gain, according to the results of the late-breaking CRISTAL trial presented Sept. 25 at the 22nd annual Transcatheter Cardiovascular Therapeutics (TCT) scientific symposium.

The CRISTAL trial, a prospective randomized clinical trial, compared balloon angioplasty to the use of the Cypher Select sirolimus-eluting stent in patients who developed restenosis after implantation of a Cordis Cypher stent (n=120) or a Boston Scientific Taxus stent (n=120), according to the study’s principal investigator, Bernard R. Chevalier, MD, of the Institut Cardiovasculaire Paris Sud.

The patients within Cypher group were then randomized at a 2:1 ratio to receive a Cypher stent (n=80) or PTCA (n=40)—the same number of patients in the Taxus group were randomized to recieve either Cypher or PTCA. The researchers also evaluated 80 patients who developed restenosis in a bare-metal stent—all 80 received the Cypher Select.

According to Chevalier, the researchers hypothesized that Cypher Select stent placement would have a lower late lumen level than PTCA for the treatment of a restenosed Cypher or Taxus stent, which the researchers evaluated in a pooled analysis.

There were 197 patients in the Cypher/Taxus pooled analysis in which 136 received the Cypher Select and 61 received repeat PTCA.

Chevalier and colleagues used angiographic endpoints including pre-procedural MLD, post-procedural MLD, follow-up MLD and late lumen loss in the pooled study cohort.

"We saw that pre-procedural MLD was no different between the two groups [Cypher and PTCA]; however post-procedural MLD was much higher in the Cypher arm compared with PTCA –2.51 versus 2.12,” Chevalier noted.

“The surprising results came from the PTCA group, which had a late lumen loss of 0.41 compared with 0.37 in the Cypher arm.” Chevalier noted that the follow-up MLD levels during the trial were recorded to be higher in the Cypher group as compared with the PTCA group, 2.14 versus 1.71, respectively.

“There was no difference between Cypher treatment and PTCA in the primary endpoint of late lumen loss, but significant differences in follow-up MLD, acute gain and net gain, all in favor of the Cypher stent treated group.”

Chevalier speculated that the reasoning for these differences is the likely fact that post-balloon recoil acted as a factor in the primary endpoint analysis.

Additionally, he said that “there was no significant difference between the two groups regarding cardiac death, non-cardiac death and Q-Wave MI. However, he did report that there were clinically significant differences in the rates of target lesion revascularization (TLR). These rates were 5.9 percent in the Cypher stent arm compared with 13.1 percent in the PTCA arm—a relatively low rate of TLR for primary angioplasty, he noted.

Additionally, Chevalier said that there was no statistically significant difference in target vessel revascularization (TVR) between the two groups; however, there was one reported case of stent thrombosis in the Cypher group.

The researchers also compared the angiographic endpoints for initial stenting with Cypher, Taxus and BMS groups. “We saw no significant differences between the Cypher and Taxus stents; however, we did see that there were lower rates of pre-procedural MLD when a bare-metal stent was used,” he noted.

The authors found that the rates of post-procedural MLD were 2.42, 2.36 and 2.51 for the Cypher, Taxus and BMS groups, respectively. Additionally follow-up MLD rates were higher in the BMS group compared to the Cypher and Taxus groups, 2.27, 2.02 and 2.00, respectively.

“The performance of Cypher seems superior in BMS restenosis than in DES restenosis with the limitation of differences in baseline characteristics,” he concluded.