Can you describe the TC-WYRE study?
The TC-WYRE (TAXUS® Stent-Cypher® Stent What's Your Real World Experience) study is a large, retrospective clinical evaluation of one-year outcomes among 1,558 patients who received either a TAXUS Stent or Cypher Stent at 19 centers throughout the United States. TC-WYRE is a real-world study of drug-eluting stents (DES). In other words, it evaluated the real, complex, diverse patient population we treat every day in our cath labs. The primary endpoint of the study was target vessel revascularization (TVR) at one year. This study is sponsored by Boston Scientific Corporation.
What were the major findings of the TC-WYRE study?
Both the TAXUS Stent and the Cypher Stent performed very well in this real-world setting. Both DES reported comparable safety and efficacy data, with TVR rates at one year of 3.2 percent for the TAXUS Stent versus 4.4 percent for the Cypher Stent (p=0.23, Figure 1).
These TVR rates are extremely low, especially compared to bare-metal stents (BMS), which generally have TVR rates of 20 to 30 percent one year after implantation. However, it should be noted that BMS were not evaluated in TC-WYRE. Lower TVR rates mean that patients have a better chance of avoiding a repeat procedure, and therefore potential complications associated with a re-intervention. Patients in TC-WYRE also had low and comparable Major Adverse Cardiac Event (MACE) rates of 7.2 percent for the TAXUS Stent compared to 7.3 percent for the Cypher Stent (p=0.99).
Importantly in light of the recent safety issues highlighted in the media and at scientific events both groups had low thrombosis rates at one year (0.9 percent for the TAXUS Stent versus 0.8 percent for the Cypher Stent, p>0.99). This is important because the study involved more than 1,500 real-world patients; thus, it closely reflects everyday experience. These data are reassuring for both interventionalists and patients, as they reaffirm that DES are associated with a low risk of thrombosis, at least up to 12 months.
Were there any significant differences between stent groups in the TC-WYRE study?
It is interesting to note that the TAXUS Stent was associated with a statistically significant lower rate of target vessel revascularization (TVR) among diabetics than was the Cypher Stent (Figure 2). This is an important finding in this population, which is very difficult to treat and often requires repeat procedures.
What is the significance of the TC-WYRE study?
TC-WYRE is significant because it represents the patients we treat on a daily basis and therefore offers us a snapshot of DES in real-world use. Unlike clinical trials, which often exclude the most complex patient populations, TC-WYRE evaluated patients of all ages and different comorbidities.
How do the results from TC-WYRE compare to previous studies?
The positive findings of TC-WYRE are consistent with those from other major studies such as the REALITY and the S.T.E.N.T. trial, the two largest studies of their kind to compare the TAXUS Stent and the Cypher Stent. As for the smaller, single-center studies that suggest differences in DES, it is very hard to compare findings from these studies to findings from large, multi-center trials like TC-WYRE, REALITY and S.T.E.N.T. It's like comparing apples and oranges.
Recently, safety in DES has been a hot topic. What best practices do you employ to achieve the best outcomes with stents?
First, it is important to note that the results of TC-WYRE reinforce the safety and efficacy of DES.
To achieve the best possible outcomes, I use both pre- and post-dilatation techniques. In addition, proper sizing of the stent is critical. If the stent is oversized, it can cause edge dissections, which may be a source of sub-acute thrombosis. I sometimes use intravascular ultrasound (IVUS) to determine if there are characteristics of the stenosis that may hinder proper stent deployment, such as severe calcification. Prior to the procedure, IVUS can also help determine the size of the vessel. After the procedure, IVUS can be used to confirm that you have deployed the stent properly, especially if something doesn't seem right angiographically.
Another important issue to consider is the patient's dual anti-platelet regimen. Right now, I support the ACC/AHA guidelines of prescribing Plavix® and aspirin for at least a year after stent implantation. However, the final decision must be based on individual patient characteristics and risk factors and under strict guidance from his or her physician.
Plavix is a trademark of Sanofi-Aventis.
Cypher is a trademark of Cordis Corporation.
Sponsored by Boston Scientific Corporation.