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Two Year Results for TWENTE Published: Medtronic Resolute and Abbott Xience Stents Show Excellent Results and Safety
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Abbott Xience V and Medtronic Resolute Stents |
June 26, 2013 -- Two year results from the TWENTE clinical trial, which compared two second-generation drug-eluting stents, are reported in the current issue of the Journal of the American College of Cardiology. At one-year, the two stents, Medtronic's Resolute zotarolimus-eluting stent and Abbott's Xience V everolimus-eluting stent, had similar clinical outcomes in 1,391 "real-world" patients, randomized 1:1 to either stent.
Angioplasty.Org previously reported on the one year results of the TWENTE trial when it was published in JACC last February.
Slight Increase in Endpoint at End of Second Year for Both Stents
The two year results show an increase of about 3% for both stents in the primary endpoint of target vessel failure (TVF), a composite of cardiac death, target vessel–related myocardial infarction, and target vessel revascularization, with no significant difference between the two stents. At one year TVF had occurred in 8.2% of patients for the Resolute zotarolimus-eluting stent, and in 8.1% of patients for the Xience everolimus-eluting stent (p=0.94). One year later, TVF had occurred in 10.8% vs. 11.6% (p = 0.65). While there were more cases of clinically-indicated target lesion revascularization seen in the Resolute (4.9% vs 2.6%, p = 0.03) there was more cardiac death seen in the Xience, so the composite endpoints were statistically similar.
Real World Off-Label Patient Population and Only One Year of DAPT
TWENTE was an investigator-initiated single-center trial in which almost 80% of patients had complex lesions and other off-label indications for the use of DES. 21% of the patients were diabetic. The only major exclusion criterion was recent STEMI (ST-elevated myocardial infarction). Another interesting fact about the conduct of the TWENTE trial was that follow-up, both at one-year and two-years, was 100%.
The trial includes the phrase "stringent discontinuation of dual antiplatelet therapy after 12 months" because, in accordance with the European guidelines, DAPT was stopped at one year - only 5.4% of the patients continued with DAPT past that point, providing a real-world test for the longer-term efficacy and safety of these devices.
Safety of 2nd Generation DES Confirmed
Prof. Clemens von Birgelen |
One of the main concerns with 1st generation DES was the annually increasing risk of stent thrombosis. Very late stent thrombosis (after one year) continued to increase over time with Taxus and Cypher, most likely due to an inflammatory response to the polymer. But the newer stents, typified by Resolute and Xience, have thinner struts, and thinner more biocompatible polymers. Two-year rates of definite or probable stent thrombosis were 1.2% and 1.4%, respectively (p = 0.63). And, most importantly, very late definite or probable stent thrombosis occurred only in 2 patients in each study arm (0.3% vs. 0.3%, p = 1.00), leading principal investigator, Prof. Clemens von Birgelen to conclude: "...the TWENTE trial provides interesting safety information on stringent discontinuation of DAPT at 1 year after PCI in a study population with many complex patients and lesions treated with Resolute ZES and Xience V EES."
Newer Stents Have Provided Major Change in Outlook for PCI
Shortly after the one-year results of TWENTE were published last February, the Resolute Integrity stent was granted FDA approval, and was subsequently okayed specifically for use in diabetic patients. Along with the Xience and other newer generation devices, these stents have proven to be safe and efficacious in a wide spectrum of complex lesions. Compared with the landscape from seven years ago, when the safety of DES first came into question and usage dropped precipitously, the current crop of drug-eluting stents have fulfilled the original promise of this technology: to provide a safe and durable solution to revascularization via catheter-based procedures.
Reported by Burt Cohen, June 26, 2013
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