麻豆传媒

The everolimus-eluting Xience stent continues to be the winner at two years in a pair of trials with head-to-head comparison with the paclitaxel-eluting Taxus stent, researchers affirmed.

The Xience stent was both more effective at preventing restenosis and safer in terms of thrombosis in longer-term follow-up with the second-generation stents in the SPIRIT IV and COMPARE trials reported online in the Journal of the American College of Cardiology.

These findings mirror the data presented from the trials at the Transcatheter Cardiovascular Therapeutics meeting last fall.

The late clinical follow-up also fits with the overall picture that has emerged from trials comparing everolimus- and paclitaxel-eluting stents, Fernando Alfonso, MD, PhD, and Cristina Fernandez, MD, PhD, both of Clinico San Carlos University Hospital in Madrid, wrote in an accompanying editorial.

Alfonso and Fernandez pooled the results of all four randomized clinical trials that have compared the two types of stents (SPIRIT II, III, and IV and COMPARE) and the results consistently favored everolimus-eluting stents:

• For total mortality, the risk ratio was 0.85 (95% confidence interval 0.63 to 1.14)
• For myocardial infarction, the risk ratio was 0.57 (95% CI 0.45 to 0.73)
• For combined cardiac death or MI, the risk ratio was 0.67 (95% CI 0.54 to 0.83)
• For ischemia-driven target lesion revascularization, the risk ratio was 0.59 (95% CI 0.47 to 0.73)
• For definite or probable stent thrombosis, the risk ratio was 0.35 (95% CI 0.21 to 0.60)

Cath labs have already moved on to newer generations than used in any of these trials -- with the Xience Prime, Promus Element, and Taxus Element taking over shelf space, the editorialists noted.

Despite such "overriding enthusiasm" for novel devices, interventional cardiologists should have learned their lesson from embracing first-generation devices before finding out about the late stent thrombosis risk, Alfonso and Fernandez suggested.

In such context, the longer-term follow-up from SPIRIT IV and COMPARE is valuable, they explained.

"Their findings demonstrate that second-generation DES help the field to move beyond momentum," the editorial concluded.

SPIRIT IV and COMPARE were similar in many regards but did differ in that the former was a large multicenter trial of relatively selected patients and lesions, whereas the latter was a single-center study that included complex patients in real-world practice.

SPIRIT IV included complete follow-up through two years for 3,578 of the original 3,687 patients with up to three noncomplex previously untreated native coronary artery lesions randomized to the Xience V versus Taxus Express stent.

In the results of the SPIRIT IV analysis, Gregg W. Stone, MD, of Columbia University Medical Center in New York City, and colleagues reported in JACC, the two-year results favored Xience as follows:

• Lower composite rates of cardiac death, target vessel MI, or ischemia-driven target lesion revascularization (6.9% versus 9.9%, P=0.003)
• Fewer overall MIs (2.5% versus 3.9%, P=0.02)
• Fewer Q-wave MIs (0.1% versus 0.8%, P=0.002)
• Less stent thrombosis (0.4% versus 1.2%, P=0.008)
• Less ischemia-driven target lesion revascularization (4.5% versus 6.9%, P=0.004)

There were no significant differences in rates of all-cause and cardiac mortality, nor did any significant differences in adverse event rates show up between years one and two.

The COMPARE trial reported by Pieter C. Smits, MD, PhD, of Maasstad Ziekenhuis in Rotterdam, the Netherlands, and colleagues included two-year follow-up for 1,795 of the original 1,800 patients randomized to the Xience V or Taxus Liberté stents with few exclusion criteria.

The two-year results again showed advantages to the Xience stent as follows:

• A lower rate of the composite of all death, nonfatal MI, and target vessel revascularization (9.0% versus 13.7%, relative risk 0.66, 95% CI 0.50 to 0.86)
• Less MI (3.9% versus 7.5%, RR 0.52, 95% CI 0.35 to 0.77)
• Less target vessel revascularization (3.2% versus 8.0%, RR 0.41, 95% CI 0.27 to 0.62)
• Less definite or probable stent thrombosis (0.9% versus 3.9%, RR 0.23, 95% CI 0.11 to 0.49)

COMPARE showed a significant divergence in favor of the Xience stent in the second year of follow-up compared with the first for the primary composite endpoint (P=0.04), target vessel revascularization (P=0.02), and stent thrombosis (P=0.02), whereas SPIRIT IV did not.

Another notable difference between the trials was that COMPARE showed a drastic drop-off in maintenance of dual antiplatelet therapy in the second year (13% versus 70% at one year) while SPIRIT IV did not (69% and 92%, respectively).

"Whether this may explain the differences beyond the first year that were detected in COMPARE despite its smaller size remains speculative," the editorialists wrote.

SPIRIT IV included more diabetes patients (32% versus 18% in COMPARE), but both trials showed a potential interaction with stent type such that everolimus-eluting stents were no better than paclitaxel-eluting stents in this population.