The risk of stent thrombosis in patients treated with a bare metal stent (BMS) is greatest in the first days to weeks after implantation. Cessation of dual antiplatelet therapy (DAPT) during this period, particularly in cases of patients undergoing surgery, is associated with an unacceptable rate of stent thrombosis, which is often catastrophic. Thus, a minimum duration of DAPT for 1 month is generally recommended in stable ischemic heart disease (SIHD) patients treated with a BMS.

The risk of stent thrombosis in SIHD patients treated with currently used drug eluting stents (DES) is greatest in the first 3 to 6 months after implantation. Accordingly, in SIHD patients with newer generation DES, the recommended minimum duration of DAPT is 6 months. This differs from previous recommendations of SIHD patients treated with first-generation DES where the recommended minimum duration of DAPT was 12 months. Since currently used newer-generation DES have a lower risk of stent thrombosis compared with first-generation DES they require a shorter minimum duration of DAPT. Randomized controlled trials of primarily low-risk (non-ACS) patients treated with DES comparing shorter duration (3 to 6 months) DAPT with 12 months of DAPT — as well as several meta-analyses — did not find an increased risk of stent thrombosis with shorter duration DAPT. Therefore, in patients with SIHD treated with currently used DES, the minimum recommended duration of DAPT has been decreased from 12 to 6 months.

DAPT beyond the minimum recommended duration of therapy is a tradeoff between decreasing ischemic risk (e.g., MI and stent thrombosis) and increasing bleeding risk. For example, prolonged or extended DAPT for an additional 18 to 36 months (in addition to an initial 6 months of DAPT) in patients treated with DES implantation results in a ≈1% to 2% absolute decrease in stent thrombosis and ischemic complications and ≈1% absolute increase in bleeding complications. Since newer generation stents, particularly everolimus-eluting stents, have lower rates of stent thrombosis, the absolute reduction in the rate of stent thrombosis with prolonged DAPT in patients treated with everolimus-eluting stents is modest, but the bleeding risk remains the same.

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References

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Keywords: Coronary Artery Disease, Drug-Eluting Stents, Hemorrhage, Risk, Stents, Thrombosis, Platelet Aggregation Inhibitors

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