Stent thrombosis prevention


 * Associate Editors-In-Chief: Smita Kohli, M.D.; Varun Kumar, M.B.B.S.; Lakshmi Gopalakrishnan, M.B.B.S.

Overview
The main principle of the preventive treatment for stent thrombosis is to perform the best PCI possible, including good expansion and apposition of the stent. In this context, the role of intravascular ultrasound has been studied extensively and can be helpful.

Combined antiplatelet therapy for the preventive treatment has been extensively studied and are routinely recommended.
 * There are better outcomes noted with the use of aspirin plus ticlopidine or clopidogrel than with aspirin plus warfarin or aspirin alone.
 * Preliminary evidence suggests prasugrel resulted in fewer ischaemic outcomes including stent thrombosis than with standard clopidogrel.

Clinical trial data

 * In STARS trial, studying 1653 patients showed superiority of aspirin and ticlopidine over combination of aspirin and warfarin or aspirin alone for reducing subacute stent thrombosis, although there were more hemorrhagic complications than with aspirin alone.


 * A similar benefit for combined aspirin plus ticlopidine was noted in another randomized controlled trial.


 * Results from double blinded randomized studies- PCI-CURE trial, analyzing 2658 patients and CREDO trial , analyzing 2116 patients, revealed the benefit of clopidogrel therapy increased with time and provide evidence for at least one year therapy in patients with BMS. However both the studies did not evaluate DES.


 * TRITON TIMI-38 trial analyzing 12,844 patients who underwent stenting for ACS revealed intensive antiplatelet therapy with prasugrel resulted in fewer ischaemic outcomes including stent thrombosis than with standard clopidogrel.These findings were statistically robust irrespective of stent type, and the data affirm the importance of intensive platelet inhibition in patients with intracoronary stents.

Guidelines for Prevention
The 2008 American College of Chest Physician illustrates the following guidelines for primary and secondary prevention of coronary artery disease.

1. For patients after myocardial infarction, after ACS, and those with stable CAD and patients after percutaneous coronary intervention (PCI) with stent placed, we recommend daily aspirin (75–100 mg) as indefinite therapy. (Grade 1A).

2. For patients who undergo bare metal stent placement, we recommend the combination of aspirin and clopidogrel for at least 4 weeks (Grade 1A).

3. For patients undergoing PCI with BMS placement following ACS, we recommend 12 months of aspirin (75–100 mg/d) plus clopidogrel (75 mg/d) over aspirin alone (Grade 1A).

4. For patients undergoing PCI with a DES, we recommend aspirin (75–100 mg/d) plus clopidogrel (75 mg/d for at least 12 months) [Grade 1A for 3 to 4 months; Grade 1B for 4 to 12 months]. Beyond 1 year, we suggest continued treatment with aspirin plus clopidogrel indefinitely if no bleeding or other tolerability issues (Grade 2C).