Cypher/Taxus: No Increase in Thrombosis
In single de novo native coronary lesions 2.5 mm to 3.5 mm in diameter and 30 mm or less in length, polymer-based sirolimus-eluting stents result in no significant increase in stent thrombosis compared to otherwise equivalent bare-metal stents. Similar results were demonstrated for paclitaxel-eluting stents.
Meta-analyses of data out to four years from independent trials of the Cypher (RAVEL, SIRIUS, E-SIRIUS and C-SIRIUS) and Taxus stents (TAXUS II, TAXUS II, TAXUS IV, TAXUS V and TAXUS VI) were carried out by researchers from the Cardiovascular Research Foundation.
The results were presented yesterday afternoon by Martin Leon, MD, CRF founder and Professor of Medicine at Columbia University Medical Center, and Gregg W. Stone, MD, CRF Chairman and also a Professor of Medicine at Columbia.
Analyses
The researchers examined freedom from all events at four years among patients receiving the Cypher (Cordis/Johnson & Johnson) stent vs. a bare-metal stent.
They found nonsignificant differences in the number of events between the groups, including freedom from stent thrombosis (five events with bare-metal stents vs. 10 events with Cypher; P = 0.20); myocardial infarction (53 events vs. 55 events; P = 0.86); all-cause mortality (44 vs. 57; P = 0.19); cardiac death (22 vs. 29; P = 0.32); and noncardiac death (22 vs. 28; P = 0.40).
As early as one year, the rate of events was not equivalent, with five events in the Cypher group vs. zero in the bare-metal group (P = .025). By four years, however, the difference disappeared.
In the composite of freedom from death or Q-wave MI, there were 53 events among bare-metal stent recipients vs. 70 events with Cypher (P = 0.12). An insignificant difference in events was also found in freedom from cardiac death or MI at four years (69 with bare-metal stents vs. 75 with Cypher; P = 0.63).
In the Taxus (Boston Scientific Corp.) meta-analysis, rates of freedom from stent thrombosis diverged between one and two years; however, stent thrombosis events at four years were not significantly different (20 with Taxus vs. 14 with bare metal stent; P = 0.29).
Curves for freedom from MI out to four years were “superimposable,” Leon said, and were not significantly different (110 events with Taxus vs. 104 events with bare-metal stents; P = .64).
This also held true for freedom from all-cause mortality (86, Taxus vs. 92, bare metal stent; P = .70), cardiac death (36 vs. 42; P = .52), noncardiac death (50 vs. 50; P = .96), death or MI (186 vs. 182; P = .77), cardiac death or MI (138 vs. 135; P = .80), or death or Q-wave MI (105 vs. 107; P = .95).
Any differences in overall rates of stent thrombosis at four years between the two stents were “nothing even approaching statistical significance, not even the shred of a signal suggesting there is a difference,” Leon said.
TLR and TVR rates
“There is a dramatic difference in terms of improvement or reduction in the frequency of ischemic TLR or TVR at highly significant levels,” Leon said (164 ischemic TLR with Taxus vs. 337 with bare metal; P<.0001; 268 ischemic TVR vs. 408; P < .0001).
“It can be concluded that in single de novo native coronary lesions with vessel diameters of 2.25 mm to 4.0 mm that are <46 mm in length, polymer-based paclitaxel-eluting stents compared to otherwise equivalent bare-metal stents resulted in no significant increase in stent thrombosis, and a small but significant increase in late-stent thrombus between one and four years of approximately 0.5%, or approximately 0.15% per year,” Leon said.