STEMI, DES, and Stent Thrombosis: Much Ado about Nothing? | CardioSource WorldNews Interventions

JACC in a Flash | While newer drug-eluting stents (DES) in patients with acute ST-elevation myocardial infarction (STEMI) have been shown to significantly reduce the rate of restenosis and target lesion revascularization, concerns about stent thrombosis (ST) rates in the longer term remain. The most recent ACCF/AHA guidelines for STEMI management recommend stents in primary percutaneous coronary intervention (PCI), but do not distinguish between bare-metal stent (BMS) or DES usage. Longer-term, 3-year results from an evaluation of the Swedish Coronary Angiography and Angioplasty Registry (SCAAR), performed by Giovanna Sarno, MD, PhD, and colleagues, comparing newer- and older-generation DES and BMS, however, could leave a mark on future guidelines.

During the study period, 34,147 patients with STEMI were treated by PCI with newer DES (n = 4,811), older DES (n = 4,271), or BMS (n = 25,065). At 3 years, the total number of events of definite ST was 544. The cumulative rates of ST up to 3 years in all three groups are shown in the TABLE. As seen in the TABLE, the ST rates deviate after the first days of follow-up with an early ST rate (up to 30 days) at 0.5% and 0.6% in the newer DES and older DES groups, respectively, versus 0.9% in the BMS group.

TABLE. Cumulative Stent Thrombosis Rate over Time

That trend continued somewhat during the first year post-PCI, but the rates seen with the DES groups started to truly diverge after that, with a definite step-up seen with older-generation DES. The ST rates in the BMS group increased constantly up to 3 years, at which point the older-generation DES carried a higher risk when compared to BMS; there was a similar risk recorded between BMS and newer-generation DES.

At 3 years, the total number of deaths was 3,579; the risk of death was significantly and constantly lower in the newer DES (adjusted HR = 0.55; 95% CI 0.48-0.62) and older DES (adjusted HR = 0.58; 95% CI 0.52-0.65) groups compared with BMS. Each DES performed similarly, with no significant differences between them (adjusted HR = 1.05; 95% CI 0.89-1.24).

The finding that the older DES group carried a higher risk of very-late ST versus the BMS group "confirms the concerns on the use of older DES in the STEMI setting, which have led to a Class IIA recommendation for the use of DES in the current STEMI guidelines," Dr. Sarno and investigators wrote. In light of the results of this study—a lower rate of ST with newer-generation stents and the constantly significant higher mortality in the BMS group—they noted that the current guidelines on STEMI might require an update.

While the guidelines state that first-generation DES do not increase early or late ST, controversy still persists regarding increased very-late ST rates; newer-generation DES, like the cobalt chromium everolimus-eluting stents studied in the paper by Sarno et al., may quiet these concerns. "As our daily practices evolve with this new knowledge, we expect that future STEMI guidelines for DES also will need to be updated," Bradley Strauss, MD, PhD, and Mony Shuvy, MD, wrote in an accompanying editorial.

One issue not answered by SCAAR: duration of dual antiplatelet therapy (DAPT). While the investigators felt it was "unlikely" DAPT duration affected very-late ST results, Dr. Strauss pointed to the lack of those data as a study limitation and felt that differences in antiplatelet agents and procedural anticoagulation also may have contributed to the outcomes seen.

Overall, he called the SCAAR results reassuring and felt they "should mitigate concerns about late and very-late ST with second-generation DES in STEMI patients." Data suggesting that patients receiving a second-generation DES require a shorter (3-month) duration of DAPT, in particular, "may even further extend the use of these DES in STEMI patients, since current guidelines require that DES must not be implanted in patients unable to tolerate or comply with a 1-year course of DAPT."

Sarno G, Lagerqvist B, Nilsson J, et al. J Am Coll Cardiol. 2014;64:16-24.
Strauss BH, Shuvy M. J Am Coll Cardiol. 2014;64:25-27.

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